ML20038B879

Containment Vessel Pile Driving Operations for 50 Mwe BWR at Genoa,Wi

ML20038B879
Person / Time
Site:	La Crosse File:Dairyland Power Cooperative icon.png
Issue date:	02/25/1963
From:	Palesch W, Weider J SARGENT & LUNDY, INC.
To:
Shared Package
ML20038B874	List: ML20038B873 ML20038B879
References
SL-2003, NUDOCS 8112090221
Download: ML20038B879 (4)

Text

~ -,-.. c-

,_,,. _ _..,_,,.,,,,,., mmay,ggg CONTAINMENT VESSEL i

PILE DRIVING OPERATIONS FOR 50MWe BOILING WATER REACTOR AT GENOA, WISCONSIN REPORT PREPARED FOR

~

ALLIS-CHALMERS MANUFACTURING COMPANY NUCLEAR POWER DEPARTMENT, WASHINGTON, D.C.

FEBRUARY 25, 1963 REPORT SL-2003 SARGENT & LUNDY ENGINEERS j

8112090221 811202 CHICAGO DR ADOCK 05000

3n_

ru?

x.:. m. w ni m ta--._n,rz w-m,.

~ m m e, m,a-,. m w e...

c- -

~

SARGENT & LUNDY E N G I N E E R f4 CHICAGO CONTAINMENT VESSEL PILE DRIVING OPERATIONS FOR 50 MWe BOILING WATER REACTOR AT GENOA, WISCONSIN ALLIS-CHALMERS MANUFACTURING COMPANY NUCLEAR POWER DEPARTMENT I.

INTRODUCTION Sargent & Lundy was authorized by the Washington D. C. office of Allis-Chalmers Manufacturing Company in accordance with Purchase Order No. DCl2100-4396 dated December 6,1962 to provide field supervision and inspection services for the reactor plant pile driving operations and pouring of the concrete for erection foundations and mud slab. Maxon Construction Company, Inc. poured the ten concrete foundations for the temporary support of the containment vessel and the 3 inch thick con-crete mud slab. Carl Bolander & Sons Company was retained by Maxon Construction Company to drive the piling shells and to place the concrete fill in the piles. The concrete was supplied to Maxon Construction Company and Carl Bolander & Sons Company by the Lacrosse Concrete Company of Lacrosse, Wisconsin.

II. SPECIFICATION REQUIREMENTS The piles were specified to be closed-end steel shells, driven to a final penetration of at least six blows per inch for the final 12 to 18 blows using a pile hammer having a striking energy of 15,000 foot pounds. The concrete fill was specified to have a minimum compressive strength of 3,500 psi in 28 days. Laboratory reports of concrete samples taken I

indicated that all concrete met the specification requirements.

The piles were arranged on a grid to provide for ease of layout and to facilitate the spotting of the piles.

1 III. DESCRIPTION OF PILES DETAILS The approved pile section was Union Metal Company mono-tube, cold-rolled, 7 gage steel piles. The bottom section had a tip diameter of 8 inches, was tapered 0,14 inches per foot and had a total length of 30 feet. The butt diameter was 12 inches. The final length of the pile JOB 3055 SL-2003

- m.n - c,.maarce =. nm ~x~mm se mg~ :

aew.=--

- mmrzery_~w.m. 7:<mm 1

SARGENT & LUNDY ENG1NEERS CHICAGO l

was attained by adding a cylindrical section hereinafter referred to as an extension. The extension had a constant diameter of 12 inches and the same gage as the bottom section of piling. The extension was pro-vided with a 6 inch long tapered section for inserting into the bottom section of the pile at the splice point.

The pile splice was accomplished by seating the extension into the partially driven pile, forcing it into place with the weight of the hammer.

A two pass fillet weld was then applied at the top of the bottom section of the pile.

The volume of concrete for the piles was 0.55 cubic yards for the 30 foot long tapered' bottom section and O. 77 cubic yards for a 30 foot long extension section.

IV. DRIVING EQUIPMENT DATA The piling was driven with a McKiernan-Terry C-5 double acting hammer with a rated striking energy of 16,000 foot pounds. The driving head (anvil), modified by the piling subcontractor from a H bearing pile head, performed very satisfactorily. The piles were driven directly without the use of a core or mandrel. Compressed air was used, rather than steam, for the energy source to drive the pile hammer. The full rated number of blows per minute and length of stroke. was obtained during the driving operations.

V.

DRIVING PROCEDURE Grade in the excavation averaged elevation 609'-0".

The dewatering system maintained ground water level at elevation 607'-0" + throughout l

the driving period. Due to the lack of resistance through the loose l

upper strata, (above elevation 600'-0"), it was found unnecessary to jet or pre-bore the first several feet of piling. The first 18 to 24 inches were driven by the weight of the hammer resting on the pile. The appropriate resistance in driving to develop a 50 ton capacity pile was generally encountered between elevations 581' to 577'.

In a few isolated cases, it l

was necessary to drive below elevation 577. See Exhibit 2 for tip elevations.

4 f

I l S L-200 3 l

.n,-

r

4

__d a

A SARGENT & LUNDY ENGlNEERS CHIC Alto VI. SCHEDULE OF PILE DRIVING.OF;EnATION Twenty-three working days were required to complete driving of a ;

1 piles, pouring of erection foundations and ppuring the mud slab. Pile driving work started on November 8, 1962 with the. unloading of piles and staking locations of the first piles to be driven. The final concrete was placed on December 6,1962.

VII.

SUMMARY

AND CONCLUSIONS No difficulty or unusual circumstances were encountered in any phase of the driving operation. As anticipated in report SL-1957, the required resistance to penetration for a 50 ton capacity pile was obtained with a pile tip elevation near 580'-0".

The pile driving operations were completed in full compliance with the specifications.

SARGENT & LUNDY w.

PM SL-2003

(ATTACHMENT 2)

,g i

ik:

l c

LI E

1

]

LIQUEFACTION POTENTIAL AT LA CROSSE BOILING WATER REACTOR (LACBWR) SITE

]

NEAR GEN 0A, VERNON COUNTY, WISCONSIN 1

1 Prepared by 041ES & MOORE 7101 Wisconsin Avenue Wasnington, D.C.

20014 1

Prepared for Dairyland Power Cooperative La Crosse, Wisconsin 54601 1

M W

Centract Number l

11166-003-27 September 23, 1979 g

u

-; +

+

J

4

..-f...s

..u...e s

..c..

m.... e.,

--~'

~ ~ "

LOneDOse T E se n.se

)*

C es *{.C.O 8 f ee tt.N8 A

..o.o so..o

c. c...., e 3..,....

c...

DAM ES 8 MOORE

-u - -~c o ~o

..,......m.

et sv u vasecovvg.

OE ws se S.

e. sim wne.es a taamaass a g g{.. vg L CO*e suLfAh f 5 tes f ut tesv*mosome ENTAL AseD a**Lito *=etM SCIE *sCE S q

-o..6v.w s..mi j

-ov., o.,

... u o~ o.c.

g, L g a,s.c f Cpee,..

w. C '4 * * *8 5 1-6 Su tT E 700. 7401 WISCON SIN AVENUE - WASHIN GTO N, D. C. 2OOf 4

• 43011 652-2265 TW X:

780-824-9 613

,il September 28,1979 h

9 Lacrosse Boiling Water Reactor Dairyland Power Cooperative I,.J Post Office Box 135 Genoa, Wisconsin 54632 i

0, Attention: Mr. R.E. Shimshak Plant Superintendent Gentlemen:

We submit herewith six copies of our report, " Liquefaction Potential at La Crosse Boiling Water Reactor (LACBWR) Site, Near' Genoa, Vernon County, Wisconsin" for your use. This report includes:

a) Brief sumaries of all previous liquefaction analyses

[

perfomed at LACBWR Site and related background studies; Details of field, laboratory and analytical investiga-b) f tions that were performed to verify the earlier find-d ings regarding liquefaction potential at LACBWR Site; and h

c) Our conclusions based on analyses and testing perfomed on undisturbed samples obtained by utilizing state-of-the-art techniques.

We have concluded in our study that a threshold liquefaction resistance level for the LACBWR site corresponds to an SSE producing an acceleration between 0.18 g and 0.20 g at the ground surface.

The scope of services for this report was prepared by us af ter discussions with Mr. Richard Shimshak of Dairyland Power Co-I operative. Three draft copies of this report were submitted to you on August 10, 1979, for your review and comment.

• f C

'!c!

D A F,1 G G C M O O r2 2 s

l-r Dairyland Power Cooperative l

September 26, 1979 Page Two It has been a pleasure to work on this very interesting

~

and challenging project. We look forward to a continued association l_

with Dairyland Power Cooperative in any of their ventures involving geotechnical and environmental studies.

l i

~

Very truly yours, DAMES & MOORE I

(pra #=h~ *M g

Harcharan Singh, Ph.D.

t Partner t-ysore Nataraja,"P

.D., P.E.

Project Engineer l-HS/MN:amc Enclosures 6

f L

T l

f

(

6 m

--w

4 I,I.

CONTENTS y

Page t

List of Figures.........................

iii List.of Tables iii

1.0 INTRODUCTION

1 1.1 General 1

1.2 Purpose and Scope

'2 2.0

SUMMARY

OF DAMES & MOORE GE0 TECHNICAL INVESTIGATION 0F 1973 3

2.1 Geology 3

j 2.2 Seismology..........................

4

~

2.3 Liquefaction Potential...................

4 1

{

3.0

SUMMARY

OF WES REPOR f 0F 1978 6

l 3.1 Background.........................

6

[

3.2 Scope and Purpose of Report 6

~

3.3 Conclusions by WES.....................

6

[

3.4 Sumary 7

~

4.0 BRIEF REVIEW AND DISCUSSION OF WES REPORT 8

5.0 REEVALUATION OF DAMES & MOORE REPORT OF 1973........

9 6.0 DAMES & MOORE RECOMMENCATIONS OF MARCH 1979 10 7.0 NRC/WES COMMENTS ON DAMES & MOORE RECOMMENDATIONS 11 8.0 TEST BORING PROGRAM 12 8.1 General 12 8.2 Drilling and Sampling Procedures..............

12 1

8.2.1 Standard Penetration Tests................

12 8.2.2 Undisturbed Sampling...................

14 8.3 Handling of Undisturbed Samples 16 9.0 LABORATORY TESTING PROGRAM.................

17 9.1 General 17 9.2 Specific Gravity......................

17 9.3 Particle Size Analyses..................,

17 9.4 Minimum and Maximum Densities 17 9.5 Dry Density of Undisturbed Samples.............

21

~-

9.6 Cyclic Triaxial Tests 21 9.6.1 Sample Preparation....................

21 9.6.2 Testing 22 i

L

h.'

CONTENTS (cont'd)

Page 10.0 LIQUEFACTION ANALYSES...................

26 10.1 General..........................

26 10.2 Liquefaction Potential 26 10.3 Evaluation of Liquefaction Potential, Approach 1 27

)

27 10.3.1 Simplified Procedure 35 10.3.2 Japanese Procedure 10.4 Evaluation of Liquefaction Potential, Approach 2 46

}

10.4.1 Soil Medei Used in the Response Analysis 46 10.4.2 Soil Properties Used in the Response Analysis......

46 10.4.3 Design Earthquake Used in the Response Analysis.....

48 10.4.4 One-Dimensional Wave Propagation Analysis........

52 10.4.5 Cyclic Shear Strength................

52 10.4.6 Conversion of Irregular Stress History Into Equivalent h

Uniform Cyclic Stress Series 52 59 10.4.7 Correction Factor, Cr..................

60 10.4.8 Factor of Safety Computation

';}

10.4.9 Discussion and Conclusions 60 11.0

SUMMARY

OF LIQUEFACTION ANALYSES AT THE LACBWR SITE....

65

]

66 REFERENCES...........................

APPENDIX:

BORING LOGS

-T O

e 6

d M

ii Ad

' i

o.

2 TABLES Number Page 1

Particle Size Characteristics..............

20 m

2 Sumary of Cyclic Triaxial Test Results.........

24 e

3 Sumary of Liquefaction Analysis, Approach 1, Procedure 1 36 o

m 4

Sumary of liquefaction Analysis, Approach 1, Procedure 2 44 5

Generalized Soil Profile and Model for One-Dimensional Wave Propagation Analysis 47 6

Sumary of Liquefaction Analysis, Approach 2 62

=.

O FIGURES 1

Plot Plan........................

13 a

2 Variation of SPT N-Values with Depth 15 3

Particle Size Analysis--Range for Sands Encountered at Site 18 4

Particle Size Analysis--Range for Gravels Encountered at Site 19 7

5 Variation of Dry Density with-Depth...........

25 6

Correlation Between Field Liquefaction Behavior of Sands for Level Ground Conditions and Penetration Resistance

]

(a,3x = 0.10 g)....................

29 7

Correlation Between Field Liquefaction Behavior of Sands for I

Level Ground Conditions and Penetration Resistance A

( a,

= 0.12 g) 30 E

8 Correlation Between Field Liquefaction Behavior of Sands for Level Ground Conditions and Penetration Resistance (a

= 0.14 g)....................

~31 max

~

9 Correlation Between Field Liquefaction Behavior of Sards for Level Ground Conditions and Penetration Resistance (a

=

max I

0.16 g)....................

32 e

g 10 Correlation Between Field Liquefaction Behavior of Sands for i

Level Ground Conditions and Penetration Resistance (a

= 0.18 g)....................

33 max iii

m FIGURES (Cont'd)

Number Page i

11 Correlation Between Fiela Liquefaction Behavior of Sands for Level Ground Conditions and Penetration Resistance 34 (a

= 0.20 g)....................

max 12 Comparison of Cyclic Shear Stress and Strength-Approach 1, Procedure 1 (a

= 0.10 g)..............

37 max 13 Comparison of Cyclic Shear Stress and Strength-Approach 1, Procedure 1 (a

= 0.12 g)..............

38 max 14 Comparison of Cyclic Shear Stress and Strength-Approach 1, Procedure 1 (a

= 0.14 g )..............

39 x

15 Comparison of Cyclic Shear Stress and Strength-Approach 1, Procedure 1 (a,

= 0.16 g)..............

40 16 Comparison of Cyclic Shear Stress and Strength-Approach 1, 41 Procedure 1 (a

= 0.18 g)..............

max 17 Comparison of Cyclic Shear Stress and Strength-Approach 1, 42 Procedure 1 (a

=0.20g)..............

max 18 Comparison of Cyclic Shear Stress and Strength-Approach 1, Procedure 2 (a

= 0.10 g to 0.20 g).........

45 mu 49 19 Typical Reduction of Shear Modulus with Shear Strain r

[

50 20 Damping Ratio for Saturated Sands............

{

L 21 SSE Horizontal Component (digitized time history )....

51

[

22 Comparison of Cyclic Shear Stress and Strength-Approach 2 53 L

(a

= 0.10 g to 0.20 g),..............

max I

23 Cyclic Shear Stress Ratio vs Number of Cycles for Initial 54 Liquefaction, Test No. 1, Depth 16 to 20 Feet.

i l

Cyclic Shear Stress Ratio vs Number of Cycles for Initial 24 55 f

Liquefaction, Test No. 2, Depth 31 to 37 Feet.

Cyclic Shear Stress Ratio vs Number of Cycles for Initial 25 56 Liquefaction, Test No. 3, Depth 41 to 52 Feet.

_[

E L

iv E

L

l ql il-FIGURES (Cont'd)

Number Page

'~

26 Cyclic Shear Stress Ratio vs Number of Cycles for Initial Liquefaction, Test No. 4, Depth 87 to 92 Feet.

57 27 Sumnary Curve Showing Effects of Density and Soil Fabric on Number of Cycles to Initial Liquefaction......

58 28 Relation Between Cyclic Shear Strength and Confiring Pressure Based On

}

Cyclic Triaxial Tests..................

61 6

3 1

d 1

d 1

N I

N V

MII

1.0 INTRODUCTION

1.1 General In 1973, Dames & Moore (D&M) performed a Geotechnical Investigation of Geology, Seismology, and Liquefaction Potential at the Lacrosse Boiling Water Reactor (LACBWR) site (Ref. 1). This study was conducted for Gulf United Nuclear Fuels Corporation.

D&M's report was submitted to the U.S. Nuclear Regulatory Conmission (NRC) in 1974, as part of the application for an operating license for the LACBWR plant (Ref. 2).

,j In the study, D&M concluded that the LACBWR plant had adequate factors of safety against potential for liquefaction under the design Safe Shutdown Earthquake (SSF) of.12 g.

NRC initiated a review of the LACBWR site and plant under its j

Systematic Evaluation Prograa (SEP) in 1978. As a part of SEP, the U.S. Army Engineer Waterways Experiment Station (WES) was requested After reviewing by NRC to review the 1973 D&M soils investigation.

the data and analyses presented by D&M, WES performed its own analyses based on interpretations of the same data. The WES report submitted to NRC, and made public in 1978 (Ref. 3), concluded that the factors of safety against liquefaction potential were considerably lower than those calculated by D&M.

Upon request of the Dairyland Power Cooperative (DPC), D&M reviewed k

the WES report and reevaluated its 1973 report in view of the WES analyses.

Based on this effort, D&M presented to NRC a position which'was essentially g

consistent with its 1973 study.

It was decided during the meeting U

with NRC on February 9, 1979, that a written raport should be prepared

[

summarizing the meeting, the reviews m3de, and the various analyses on liquef action potential for the LACBWR site.

Accordingly, a report (Ref. 4) was submitted to NRC in which D&M reiterated its earlier stan j

that the LACBWR site had adequate factors of safety against potential for liquefaction under the design SSE. However, certain questions raised by NRC regarding the lack of test data on undisturbed samples and the lack of continuous standard penetration test results could Therefore, not be satisfactorily answered with the existing data.

DPC agreed to perform modest field and laboratory investigations and limited analyses to verify the earlier findings on liquefaction potential.

i j

_l' In its March 1979 report (Ref. 4), D&M recommended a modest program consisting of a minimum of four test borings, undisturbed samplin9, and cyclic triaxial testi.,9 and analyses. After review of the D&M report, NRC approved the proposed geotechnical program and suggested minor modifica-tions.

1.2 Purpose and Scope

The purpose of this report is to sumarize all of the liquefaction analyses performed at the LACBWR site--(a) D&M (1973), (Ref.1); (b) WES (1978), (Ref. 3); (c) D&M (1979), (Ref. 4); and (d) NRC/WES (April 1979),

(Ref. 5).

Additionally, new analytical investigations have been conducted to verify prior findings on liquefaction potential.

The report is organ-ized as detailed below:

Brief sumary of the Dames & Moore soils investigation of 1973 a.

(Section 2.0).

b.

Brief sumary of the WES analysis of 1978 (Section 3.0).

}

Brief review of the WES report and discussions on the approach c.

taken by NRC (represented by WES), (Section 4.0).

d.

Sumary of the reevaluation of the report of 1973 (Section 5.0).

Conclusions 1,d recommendations for further work presented by D&M e.

in March 1979 (Section 6.0).

f.

Review coments by NRC/WES on D&M conclusions and recomendations (Section 7.0).

g.

Details of the current field, laboratory, and analytical investi-p gations performed by D&M to verify earlier findings on liquefac-L tion analyses at the LACBWR site (Sections 8.0, 9.0, and 10.0).

u 11m k

0 L

c.

l 2

F J

o.

2.0

SUMMARY

OF DAMES & MOORE GE0 TECHNICAL

}_

INVESTIGATION OF 1973

'Two studies were performed by Dames & Moore in 1973--a study of ge-ology and engineering seismology, and an investigation of static and dy-namic soil properties and evaluation of liquefaction potential.

A report containing the results of these studies was prepared in 1973 (Ref. 1)-and was presented to NRC as a part of the application for an operating license for the LACBWR plant. The conclusions of this report are discussed in Sections 2.1, 2.2, and 2.3.

2.1 Geology LACBWR is situated within the Central Stable Region of the North American continent. This region includes the dense igneous and meta-morphic rocks of the Canadian Shield and adjacent early Paleozoic sedi-

.L mentary strata.

The geologic structure of the Central Stable Region is t

relatively simple. Other than uplift and subsidence, very little struc-i tural activity has occurred in this quiescent area since Proterozoic time.

~

The region is characterized by a system of broad, circular-to-eliip-tical erosional uplifts--the Wisconsin and Ozark Domes, and three sedi-The site mentary basins--the Forest City, Michigan, and Illinois Basins.

[

is located on the western flank of the Wisconsin Arch, a southern extension of the Wisconsin Dome.

Minor structures, consisting primarily of syaclines and anticlines of low relief, :how no preferred orientation.

They are superimposed on the j

broader features in the region.

Faults in the region are believed to have been dormant since late Paleozoic time, i.e., for at least 200 million The Paleozoic strata and a/erlying unconsolidated sediments are j

years.

essentially undeformed within about 50 miles of the site.

LACBWR is located within the Wisconsin Driftless section of the Cent-

}

ral Lowland physiographic province.

This section is characterized by

~

flat-lying,. maturely dicsected sedimentary rocks of early Paleozoic age.

I Moderate-to-strong relief has been produced on the unglaciated landscape which has been modified only slightly by a mantle of loess and glacial

._f outwash in the larger stream valleys of the area.

L 3

t

~.

3 The LACBWR facilities are situated on about 20 feet of hydraulic fill overlying 100 to 130 feet of glacial outwash and fluvial deposits on the

]

east flood plain of the Mississippi River Valley.

The surface configura-tion of the underlying bedrock is unknown because of the relative paucity

~

'l cf borehole data.

The bedrock below the site consists of nearly flat-lying 1

sandstone and shales of the Dresbach Group (Upper Cambrian).

Dense Pre-cambrian crystalline rock underlying these sedimentary rocks is estimated a

d to be at a depth of 650 feet.

2.2 Seismology Based on the seismic history and the tectonics of the region, D&M concluded that the site will not experience any significant earthquake-l induced ground motion during the remaining economic life of the nuclear facility.

Historically, there is no basis for expecting ground motion of more than a few percent of gravity at the LACBWR plant site. However, three possible sources of earthquake motion at the site were considered:

The nearest zone of repeated earthquake activity, which is in a.

northerr. Illinois-southern Wisconsin.

b.

The effect of a series of events such as those which occurred in 1811-1812 near New Madrid, Missouri.

The effect of several shocks in the region which have not been l_

c.

related to any currently identifiable geologic structure or tec-tonic feature.

Af ter a careful evaluation of these possible sources of earthquake T

I motion and their possible ef fect on the LACBWR site, it was concluded that the SSE should be considered as the occurrence of an MM Intensity VI shock LJ with its epicenter close to the site.

It was estimated that the maximum horizontal ground acceleration induced by such an event would be 12 per-cent of gravity at the ground surface.

2.3 Liquefaction Potential The liquefaction potential of the granular soils underlying the ex-isting plant was analyzed by comparing the anticipated shear stresses due to the SSE with the shear stresses required to produce liquefaction at various depths.

The analysis was confined to the upper strata (from the ground surface to a depth of 100 feet) of the zone of potential liquefac-tion.

To provide pertinent subsurface data for this analysis, a field exploration and laboratory program of index properties tests and dynamic tests was conducted.

I The factors of safety against liquefaction were calculated for vari-ous depths.

The calculations were based on 10 significant stress cycles, following the engineering practice of 1973. The results of the analysis.

indicated that the calculated minimum factor of safety against liquefac-tion under the SSE was 1.47.

1 f

ein j

i f 4

4

'B

.I 6

l 1

'O 6

l h

o l

5

7.,.

3 Ti 3.0

SUMMARY

OF WES REPORT OF 1978

[

l

3.1 Background

{

The NRC requested that WES review the foundation conditions at the LACBWR site and prepare a report (Ref. 3) specifically examining

{

the earthquake safety of the pile foundation which supports the contain-i ment vessel.

I f

3.2 Scope and Purpose of Report L

l The scope of WES's report included the following:

[

a.

Review of Chapter 3, Soil Engineering Properties, in the DPC's 1

Application for Operating License for the Lacrosse Boiling Water Reactor (Ref. 2), including portions of Appendix A, entitled

" Field Exploration and Laboratory Tests," and associated design drawings.

(

b.

Performance of a liquefaction analysis using the Seed-Idriss Sim-plified Procedure (Ref. 6), assuming peak ground surface accelera-tions of 0.12 g and 0.20 g.

c.

Performance of a liquefaction analysis using Seed's empirical method (Ref. 7), assuming both the 0.12-g and 0.20-g earthquakes,

[

and comparison with a " rule of thumb" based on the Japanese ex-I perience at Niigata in 1964 (Ref. 8).

3.3 Conclusions by WES The liquefaction potential was evaluated for two earthquakes--an SSE with a peak ground acceleration of 0.12 g and an SSE with a peak l

ground acceleration of 0.20 g.

Two methods were employed in the analysis--

the Seed-Idriss Simplified Procedure and an empirical procedure.

Also, a Japanese " rule of thumb" based on blowcounts from standard penetration F

tests was used to predict liquefaction.

The following were the conclu-I sions:

a.

Liquefaction was predicted between depths of 32 and 48 feet by Seed-Idriss calculations for 0.12 g ground acceleration.

b.

Liquefaction was predicted between depths of 24 and 35 feet c

by the empirical procedure for 0.12 g ground acceleration.

c.

Liquefaction was predicted below a depth of 25 feet by Seed-Idriss calculations for 0.20 g ground acceleration.

d.

Liquefaction was predicted between depths of 25 and 60 feet and 85 and 105 feet by the empirical procedure for 0.20-g ground acceleration.

e.

Japanese experience, based on the Niigata earhquake of 1964, also indicated liquefaction potential below a depth of 15 feet (for both cases of 0.12 g and 0.20 g).

6

1-f i

f.

If lateral support was lost at the depths indicated above, piles would be in danger of failure due to buckling.

3.4 Summary Based on judgements concerning the density and strength data and on

{

analyses presented in the WES report, the soils below the reactor at the LACBWR site were predicted to strain " badly" under an SSE which produces

[

0.12 g acceleration at the ground surface. The soils benetth the reactor

~

vessel at the site were predicted to experience excessive strains and

[

liquefaction under an SSE with a peak acceleration at the ground surface of 0.20 g.

According to the WES report, because of limitations and the limited data available, it was concluded that the reactor vessel foundation was unsafe under the 0.20 g SSE, but no conclusion was reached on whether the reactor vessel foundation was safe under the 0.12 g

[

SSE.

I am, M

O M

M 6

a 7

r; 4.0 BRIEF REVIEW AND DISCUSSION OF WES REPORT The WES report, Liquefaction Analysis for Lacrosse Nuclear Power Sta-

~

tion (Ref. 3), now a public document, was discussed for the first time at a meeting with NRC on January 9, 1979.

DPC took exception to the contents of the WES report and requested that NRC arrange another meeting for discus-sion of the report after D&M had an opporcunity to review it.

As a result, a second meeting was held at NRC on February 9, 1979, during which D&M presented its review of the report to NRC.

Dr. W. F. Marcuson, the principal author of the WES report, was present at the meeting.

The details of the February 9,1979, meeting are presented in Ref. 4.

The following review coments were expressed by D&M and DPC:

In general, WES adopted a very conservative approach in inter-a.

T preting the available data.

b.

WES postulated an earthquake of MM Intensity IX as a design SSE for the LACBWR site; this was considered unrealistic.

The report consistently reflected conservatisrr in selection c.

of soil parameters, selection of cyclic shear stress ratio, and selection of stress reduction factor, which resulted in a cumulative underestimation of safety factors.

~

d.

WES performed empirical analysis based on standard penetration results and compared the LACBWR site with sites which have a

experienced much higher seismic activity.

A Japanese " rule of thumb" developed after the experiences e.

of the 1964 Niigata earthquake and based on standard penetration test results was applied to the LACBWR site; such a direct application was considered inappropriate.

}

In sumary, D&M felt that the ccnservative approach tcken by WES in f

each individual step of the analysis resulted in low factors of safety against liquefaction.

L l

r h

1 8

5.0 REEVALUATION OF DAMES & MOORE REPORT OF 1973 After the January 9, 1979, meeting with NRC, D&M reevaluated its 1973 report (Ref.1) in light of the conments and concerns raised in the 1978 WES report (Ref. 3).

In general, the D&M approach was found to be consis-tent with the state-of-the-art in 1973.

The obvious limitation of the 1973 study was the lack of liquefaction test data on " undisturbed" samples.

This limitation was indeed realized in the D&M analysis of 1973 and, therefore, a conservative approach was followed.

Two possible modifications to the D&M analysis of 1973 were consid-ered:

a.

Redrawing of the strength curves based on densities, rather than relative densities, in a manner similar to the procedure used in the WES report of 1978.

m d

b.

Selecting the design shear stress ratio corresponding to five equivalent cycles to represent more realistically the postulated design SSE.

Based on these modifications, factors of safety against liquefaction were 7

recomputed and found to be essentially similar to thnse cited by D&M in 5

1973.

]

J

[

rs um8 J

9

g:

6.0 DAMES & MOORE RECOMMENDATIONS OF MARCH 1979 all 1

The 1973 data and the analyses indicated that the factors of safety

.2 against liquefaction under the design SSE were adequate at the LACBWR site.

However, two basic issues needed to be addressed to further

},;

verify the results obtained--better definition of in situ densities at the LACBWR site, and development of continuous standard penetration test data at the site. Also, it was necessary to have better estimates of cyclic shear stresses that would result from the design SSE, and

[l better estimates of shear strength data from test results on relatively undisturbed samples.

f To address the above so.cerns, D&M recommended a testing and analysis program for the LACBWR site, consisting of a test boring program with a minimum of four borings, a modest laboratory testing program, and modest analyses.

Details on the procedures and the actual program are discussed in Ref. 4.

}

. J El m

MI

=

m M'

• 4

~

10 L

7.0 NRC/WES COMMENTS ON DAMES & MOORE RECOMMENDATIONS The March 1979 D&M recommendations (Ref. 4) were reviewed by the authors of the WES report and NRC staff and approved by NRC subject i

to WES comments.

The following are the main points of the review as b

outlined in Ref. 5:

[

a.

The program outlined by D&M is acceptable for determining i

the potential for liquefaction in the immediate vicinity of the containment building of the LACBWR plant.

i b.

i Additional borings may be required near the turbine building and the cribhouse, c.

State-of-the-art techniques should be employed to obtain undis-turbed samples in cohesionless soils, d.

Comercial transportation of samples should be avoided.

_J A sufficient number of cyclic triaxial tests should be perfcrmed e.

to cover all the depths and confining pressures of interest and to obtain a good definition of strength at different con-I fining pressures and at different significant stress cycles.

f.

Analyses should be performed to cover a range of assumed peak ground acceleration levels between 0.12 g and 0.20 g, so that a threshold liquefaction resistance level can be estimated for the LACBWR plant site.

The remaining sections of this report describe the actual test boring program, the laboratory testing program, and the analyses performed to estimate a threshold liquefaction resistance level for the LACBWR

]

plant site.

1 i

k 3

7c w

11

8.0 TEST BORING PROGRAM 8.1 General Five additional borings were drilled at the LACBWR site to obtain 7

more complete data for verification of the earlier liquefaction analyses.

I Two borings were drilled on each side of the reactor building near 1973 borings DM-1 and DM-3, and a fifth hole was drilled near the cribhouse iL near boring DM-5.

Approximate locations of the new borings (DM-7 through DM-11) are shown along with the earlier borings on Figure 1.

Detailed

[

descriptions of the soils that were encountered are presented on boring logs in the Appendix.

Three of the borings (DM-8, DM-10, and DM-11) provided standard penetration test (SPT) blow cou,nt, at 5-foot intervals throughout the

}

depth of the holes; continuous blow counts had been precluded in previous borings by the use of several types of samplers in each hole.

Borings DM-7* and DM-9 yielded relatively undisturbed samples suitable for density determinations and laboratory cyclic triaxial strength testing.

]

The split-spoon samples from the SPT holes were used for field classifica-tion and laboratory confirmation of index properties.

~

8.2 Drilling and Sampling Procedures Drilling operations were performed by Raymond International of 5

Chicago, using a Mobile 8-61 truck-mounted rotary wash drill rig.

d The rig was leveled before beginning each hole to ensure vertical drilling.

Drilling to the specified sampling depths was done with a 41/8-inch i

tri-cone roller bit attached to A-size drill rods, with side discharge of drilling fluid to minimize disturbance to soil below the bit. Casing was advanced at intervals to keep the hole open as drilling progressed, j

and a thick drilling mud was mixed and maintainec above the grcundwater 9

level in the hole at all times.

When completed, each hole was grouted LAF without pressure with a thick cement slurry to prevent caving.

N 8.2.1 Standard Penetration Tests.

The standard penetration tests (SPT) were performed at 5-foot intervals in borings DM-8, DM-10, and P

DM-11 to provide blow-count values for all depths to be considered b

• In DM-7 samples were taken alternately every 5 feet by the Osterberg piston sampler and the SPT split-spoon.

12

o a

e r

l A.

,u f * " " " *t ( 4) 0 0.. s.t. 1 O.aAf g

v em cm. r

- __J 9

m.,

m

,7*

4,...

c V

5P h 00

/

)

s.oce.:v a tDam A

W 1L t?'

Domitas. 0g.,

e T

'l St DG g

.~.

g y

acais Du.o s* >.$ *

/

4.7

/,, $

w

.ac,

- e..

"I e..c e

~

.4...,,

8 m

-)

=

o,...,

OFFICES 4,

b m

-c.d..

.g.,,,,,,, g...

4...

m,

s,.,/rf ~NO.,

g~

(

(

+ - + -

,/

} g

,j

)!

b

/

F t

l m

i s

/

i u

\\_

J P

.o.e-a'

...c w v.

c.y~e'_

3

. - ~,

m sj

_. y s

4.o..

3

{

l.-

o,, o 7

i Da l

PLOT PLAN q"

4 TEST BOR!NG FOR D&M INVESTIG ATION IN 1973 l

l j'* TEST BORING BY R AYMOND a

r-

~'

N INT *L IN JULY 1962

,s m esi 6" mau"""-

4 y

TEST BORING FOR D&M 4v 1NVESTIGAT10N IN 1979

!1+

L DAh.ESS eOO a 1

FIGURE 1 13 l

k. '

in the analysis, and to provide samples for field classification and laboratory verification of index properties.

Sampling was done in accordance with ASTM 0-1586-67 (Standard Penetration Test) specifications, using a calibrated 140-pound pin-held hommer dropping 30 inches.

The pull rope used was old and flexible, wrapped two turns around the cathead, and was oiled frequently to minimize friction and approach as free a fall of the hanmer as possible. The 2-inch split-spoon was driven 18 inches into the soil, and blow counts were recorded in 6-inch incre-ments. The split-spoon was then slowly withdrawn and the disturbed sample was preserved for classification and testing after field iden-tification.

Figure 2 shows N-values plotted with depth for all borings; 7

j these values represent blow counts for the last 12 inches of each sample.

j_

8.2.2 Undisturbed Sampling. Relatively ur. disturbed samples were obtained at 5-foot intervals in boring DM-9 and at 10-foot intervals in DM-7.

Samples were taken in thinwall tubes by means of an Osterberg piston i

sampler. The tubes were coated with polyurethane to minimize frictional disturbance.

Before each sampling operation, the piston sampler was cleaned and oiled and extended by hydraulic pressure applied by the rig to ascertain that grit would not hinder its even extension into the soil once it was lowered to sampling depth. When clean, the sampler was lowered n rest on the bottom of the hole, and the tube was extended I

30 inches into the soil by even hydraulic pressure.

The rig was chained down during the sampling to prevent uplif t of the rig and uneven pressure l

application on the sampler.

}

The sampler was then slowly withdrawn from the hole, maintaining the mud level near the top of the hole.

When the sampler cleared the

}'

top of the casing, a small amount of soil was removed fror the bottom j

of the tube (and dimensions recorded) to permit insertion of a solid cap in the end of the tube.

The purpose of the end cap was to prevent c

loss of sample material and moisture during removal from the sampler.

The sample tube was then severed at the top of the sample with a pipe cutter to release any vacuum within the tube and minimize disturbance while disengaging the tube from the sampler. The tube was capped on f

top, while maintaining its vertical orientation, and carried by a D&M I

field engineer to the onsite laboratory for measurement and storage.

14

N(blows / foot) o

' LT W I

oOt+ 0 1

01 A AkOO 20-ex

{

&O g

KEY

\\

C DM-7 40-

@A

+ DM-8 d'

O A

M

s O DM it

+0 s

-- DESIGN N VALUES

+ N NOTE: ONLY D&M 1979 RESULTS ARE PRESENTED HERE so-A O r '-O

+

0

\\

.5 AD\\

h h+

o-

\\

8

+

A

\\

O

\\

so-OA Os\\

}

\\A O

+

\\O O +

A

.i mi

+

.J 100-O

\\ A e

g O

\\

D-0 O \\

+

A

\\ OA G-ll 120-O

\\ O

+

A m

\\

A iso-

.I.

VARI ATION OF SPT N. VALUES WITH DEPTH 15 FIGURE 2

t j

i 8.3 Handling of Undisturbed Samples

~

Field density measurements were made in an onsite temperature-controlled laboratory accessible only to the site security chief and D&M personnel.

Upon arrival in the laboratory, a sample tube was imme-diately measured and weighed, using appropriate tare weights, to deter-l mine a field density.

A small amount of soil was then removed from the top and bottom of the sample to determine moisture content. A drainage cap, consisting of two perforated metal disks separated by l

a rubber grommet, was installed in the bottom of each sample tube to

~

prevent displacement of the soil as drainage occurred. The rubber grommet could be tightened or loosened by means of a wing nut.

The sample was covered with a non-airtight cap and allowed to drain at least 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> in a vertical tube rack.

It was anticipated that, after drainage of the free water, freezing of the remaining capillary moisture would create minimal, if any, disturbance of the structure of the sand

]

samples. This freezing technique currently is considered the best means of preserving the structure of clean, loose sands below the water table for transport and testing (Ref. 9).

Af ter draining, the samples were placed in vertical racks in 55-gal-lon drums and packed with dry ice surrounded by shredded insulation.

The samples were allowed several hours to freeze, checked by a short length of tube filled with water (which froze completely within a half

~

hour).

The drums were then transported to a commercial cold-storage

]

plant in Lacrosse, where they were stcred at -20 F for the duration d

of the field operations. Upon completion of the drilling program, the samples were repacked in dry ice and insulation ano driven to Chicago J

for laboratory testirg, where they were unloaded and stored in a freezer maintained at about -10 F.

The sample transport was performed by a I

D&M field engineer to ensure careful handling.

W W

w 16

9.0 LABORATORY TESTING PROGRAM 9.1 General The purpose of the testing program was to provide additional strength data from undisturbed samples for the liquefaction analysis, and to make a limited number of confirmations of index properties.

In addition to 15 stress-controlled cyclic triaxial tests, testing included specific

_j gravity determinations, particle size analyses, minimum and maximum density determinations, and measurements of dry density of the undis-turbed samples.

9.2 Specific Gravity Determinations of specific gravity of sands at the site were made in the D&M laboratory in accordance wth ASTM D-854-58 (Specific Gravity of Soils).

Tests of four samples from depths of 31 to 47 feet yielded

~'

specific gravity values ranging from 2.60 to 2.65.

These results cor-

~'

relate with expected values for such soils and with 1973 results.

~

9.3 Particle Size Analyses Particle size analyses were performed on 25 samples from boring DM-10 by a D&M laboratory according to ASTM D-422-63 (Particle Size Analysis of Soils). Results are shown as ranges for the sandy and a

gravelly soils respectively, on Figures 3 and 4.

The coefficient of uniformity, Cu (Table 1), or ratio of D60 IO, provides a useful

• to D comparison of grain-size distribution at various depths and can be used in relative density calculations.

_1 9.4 Minimum and Maximum Densities Minimum and maximum densities for a composite of samples between 31 and 47 feet were determined in the laboratory by using equipment and methods similar to those specified by ASTM D-2049-69 (Relative Density of Cohesionless Soils). These tests produced an average minimum dry density of 97.2 pounds per cubic foot (pcf) and an average maximum of 114.3.pcf. Relative density, D, could then be calculated by compar-r ing these densities with measured in situ densities.

~

• D refers to the grain size which is coarser than 60 percent of the 60 sample by weight.

0 is defined similarly as coarser than 10 percent 10 of the sample

~~

17 7

0

lll l

J-1 0

l 0

O J

l!

{,

l l

l 1

Y A

l-l l

j i

i L

i l

j C

l 1

R

^

0 f

0 O

I l

!i 1

I 0

lj.I I!

0 i

I i

l iil

l lJ f

2

-I]I,

1,jj}!

lI j

l

i. }

~

N 8

N 0

R E

0 I

g 1 Q S

T

t 01

(

l E

I R

I S

N t

E F

1 0

TM " y T

N A

T 6

k I

E

{)*

4 3.

- c M

SD

(

0 1

}

i' l

7 l

S E 1

i'!I I

E 4 I

I 1}

D\\

l jl IL D

YR k](

I S V AT L

N 1

Z k

A M L E

+

S 0 I

s'

0. M l

N N O

h 2

1 N

A U I

E

)

E Q

Z I

M O

V E C l

E S 0 lIP I

l y_h O

1 Z

E I N

{l I

ll i

E l

ll(p'

[

. I SE I

S

\\

S R

ES

[

D A

LD R

N A 4 l!U' f3 g,

I I

j I [

I l

l I

I I

Il CN N

C I

N A

T A i

D

~

'2 R

R S

)

Nt

\\

A8 G

E AR I

~

T/

1 e

o I

PO N

S 3 F 1-F n

. N.

'5 i

d t

F f

n W

S. 4 0

h ga L

E 1

1 ntins E

G e wieys l

I l

I I

VI N

t U/

l l

l j

l I

a e 3

l r

r r A

gd a a e - nvol R

A v ya e

G E R

N

,cv Q

1 a a s l f r r a

S t

g gmiog R

r 5

I g r s

A uf s n oiot e

O 1

id n d nn C

es uf i

1 l

w mc o N

u e

d 3

lij,'Ji c o I

l l

l lI x

oramn,h r

aa, 0

Q Bt t

0 (e 1 '0 N:

II 0

1 M2 O D1 I

S

- T

0 I

G : PI E

L NHR 8

I T C B

OE E

,b_

RP S O

i C

DDD t

~

[

~

~

[!

0

~

[

0 0

0 o0 i

N 4

2 1

i FI9 h b x$g F[

E 1

t t

O3Il a 0il

'w i

2smm W 1

l r r,-

8 l

i 6

t I

i I

e 4__.4 j.

..4 j

f

.2 f

M.-_4 4

.S j

j 4..

J 4-__<- -..

l._-

s

)

U s

2 L.._

4, 4,

,.i O

cc

[.. - 4_

-. + - - -.. _

s

.s..

O O

I 6

I b

_t--. {

i.

[

} j 1'

E i

I

{

. _ _p.-

4 5

.t j.

i

.__ j.

-.1.

j. _

p p.

l

.._..l..

4 L

.t 7

g2. g.,_ 4. _

. j_

_4_

i g

I '1._-... g... -..

{!.Qf g

4 i

j o

H 8

__d 4

i i

I m

m l

w E

Z 1

O W

C 4

"l i

F W

o W

m i

O

-.d:- :

2

]

Gg

- a ::::- -

2 wT

>m e

L 4

5. L _

s z

-I k N

mO

--t -

2 m 2 z -)

r1 a 2 (Z

o

<o w*

j [/',

.--) _., _-i. -- -d _--=l (

y w o l

1 I

z l

N 2

=

w l

i l

W

- f--__---

W G)

EO

.=-

_ _ - - _. e N

w u

i i

t i

us Wg O

l

.., _.._. j_.

I..

u) ct aw I

_1 (

5 5:!><

_.. _ _______._/__ t_ __ s z

27 a

_y ozY WW 4 co

+/,/

i -

E 40 o

w a

Hs g

m{..

o o

2 m9 g

'1'/

3 u.

- z i

s

m. -

D w

LLI m 'g -

T I

si e

3g 4__.-

4 l

z

/_

$ 3 =U z

w j,

y o - =t9 E

E 8.E M

l E

at

• • C O

U 1".

}

. y 7 ;; 3 g ;

i r.2 8

i<

28o O - ;-

g 44 a.g j

.J

-Hu

__c a m e

m omw o

eaa

_.J.

..__ j_.._ p_.__

p.. g_ t.

drdr

-i. nk-i~.

!...1

~

g 8

8 8

R Po S

V 2

8 9

1H913M A8 H3 NI.d I N '3 W H P'

onu ms a e.coosem 19 FIGURE 4

.]'

TABLE 1 PARTICLE SIZE CHARACTERISTICS Depth 0

• D 0

u 10 50 60

=D

/0 (ft)

(am)

(mm)

(mm) 60 10 10 0.12 0.40 0.42 3.5 20 0.20 0.42 0.43 2.2 1

30 0.15 0.44 0.51 3.4 40

• 0.15 0.41 0.49 3.3 50 0.16 0.39 0.42 2.6 60 0.16 0.54 0.67 4.2 70 0.18 0.39 0.43 2.4

}

80 0.18 0.41 0.43 2.4 90 0.20 0.66 0.72 3.6 100 0.19 0.62 0.71 3.7 c

)

i 1

h li Y

l L,

• D refers to the grain size which is coarser than 10 percent of the 10 sample by weight. 0 and D are defined similarly, i.e., they are 50 60 coarser than 50 percent and 60 percent, respectively.

F 20 c

e

i i

_6*

~

=

Relative densities were also calculated by means of an expression developed by Meyerhof in 1957 (Ref. 10) which relates relative density to blow counts and overburden stress at a particular depth.

These values were used in the Japanese analysis (Ref. 8) and in the shear modulus calculations for the one-dimensional analysis.

Another check of relative densities was made by means of the Marcu-son /Bieganousky (Ref. 11) expression involving uniformity coefficients, blow counts, and overburden stresses.

These values compared satisfactor-ily with those used in the analysis.

9.5 Dry Density of Undisturbed Samples As described previously, field densities were calculated by measuring and weighing the undisturbed samples immediately on extraction from the boring.

We believe that these values are fairly accurate because the measurements were made for the entire sample and as soon as possible after sampling.

Dry density values were derived after field moisture contents were taken from each end of a sample.

Densities were also measured on the frozen samples in the laboratory.

Sample tubes were cut into smaller sections and accurately measured, and the weight of soil solids was determined by drying the sample.

Dry densities were calculated by dividing this weight of solids by the frozen volume.

9.6 Cyclic Triaxial Tests

(

Fifteen stress-controlled cyclic triaxial tests were performed

(

on undisturbed samples in the laboratory of the University of Illinois at Chicago Circle by Professor Marshall Silver.

Samples for testing were chosen in the depth ranges of 10 to 20 feet (hydraulic fill),

30 to 40 feet, 40 to 50 feet, and 80 to 90 feet.

~

9.6.1 Sample Preparation.

In preparation for testing, sample tubes were removed from the freezer and cut into sections with a tube cutter to produce test specimens. An inch of possibly disturbed material was wasted from the bottom of each tube. A vertical band-saw was then used to split one side of the tube, which allowed the frozen sample to be extruded vertically into a split brass cyclinder for trimming and transporting.

The specimen was placed in the triaxial cell in a membrane with filter paper at top and bottom, and a small vacuum 21

of minus 5 inches of mercury was applied while thawing the specimen.

The sample was then corsolidated under a pressure slightly greater than the in situ effective confining pressure.

Specimen dimensions

~

were recorded before and after thawing and after consolidation.

9.6.2 Testing. Cyclic triaxial testing of the specimens was performed according to procedures outlined by Silver (Ref.12).

Samples were placed in a triaxial cell capable of being loaded with a periodic cyclic stress of constant amplitude.

Cyclic loading was begun and continued until double amplitude strains exceeded 10 percent, axial compressive or extensive strains exceeded 20 percent, or the predetermined number of load cycles was achieved.

These test results were evaluated with respect to the magnitude of cyclic axial stress and the number of cycles required to produce double amplitude, compressive or extensive strains of 5 percent and 10 percent. Also recorded was the first cycle at which the induced excess pore pressure became equal to the cell pressure, which is referred to as initial liquefaction. Ranges of stress ratios at failure ~were selected to obtain relationships between stress ratios and number of cycles required to cause liquefaction.

Using the weight of the solid particles, determined by drying and weighing the sand particles after completion of the triaxial test, three density calculations were made for the tested specimens. The density calculated using the frozen dimensions was called the frozen density.

After the sample was allowed to thaw for 2 or 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> in the laboratory under vacuum confinement, new diameter values were measured with the Pi tape at three locations on the specimen. The change in height in the vertical dial gage was noted. A new volume calculation for the specimen was made with the new height and diameter.

By dividing m

the new volume into the weight of the solid particles of the specimen, a

a second density was determined.

This density was called the thawed density.

The cell was then assembled around the specimen and the specimen was saturated and consolidated.

Vertical dial readings and volume

(

change readings were made and used to calculate the consolidated volume of the specimen.

By dividing the dry weight of the solids by the consoli-

[

dated volume, a third density, the consolidated density, was determined.

L l

22 l

\\

ll A suninary of densities and the triaxial test results is given in Table 2, and the variation of dry density with depth is shown in Figure 5.

T' 1

f m

m 7

_I o

f_

]

h n

l 23 1

u u

s; am um asseus

=

y a

i n.,... ]

g...i g

g g,,

g g

J TABLE 2 SUMt1ARY OF CYCLIC TRIAXIAL TEST RESULTS*

tJumter of Cycles Dry Density (pcf)

Effw tive Saturation to Liquefaction Seple/

It. awed and Confining Stress Details ta tJ tJ Test Sprimen Depth Frozen Thawed Consolidated Presst:re Itatio

'B' g

g 10 t2tnber ritnbcr (ft) Condition Condition Condition o WI I!"c (5% m (10t m c

(Initial) Strain) Strain) Pemarks 5/?

21.5 102.2 104.6 105.4 2,000 0.22 0.97 5

5 5

1 4/3 16.0 101.8 103.5 104.1 2,000 0.18 0.98 11 10 11 4/2 16.5 103.9 105.4 106.4 2,000 0.32 0.97 3

2 3

7/2 31.5 99.7 101.0 101.4 2,500 0.20 0.86 10 10 14 Icw ~B" value 2

7/3 31.0 102.0 103.7 104.2 2,500 0.28 0.99 10 12 16 8/1 37.0 104.1 105.4 105.7 2,500 0.39 0.96 6

11 25 8/3 36.5 102.9 104.3 104.8 2,500 0.12 0.99

> 1,000 > 1,000 > 1,000 Did not l i m i,. fy 10/1 47.0 in1. 6 103.1 103.7 4,000 0.32 0.95 4

3 5

10/2 46.5 103.0 104.7 105.4 4,000 0.23 0.97 5

4 7

3 9/2 41.5 103.0 104.8 106.1 4,000 0.43 0.96 5

3 6

10/3 46.0 103.5 104.8 105.5 4,000 0.18 0.99 8

8 11 11/2 52.0 103.0 104.5 105.1 4,000 0.13 0.98 84 86 92 18/1 87.0 104.7 105.8 107.8 8,000 0.35 1.00 7

8 16 4

10/2 86.5 103.6 104.6 105.6 8,000 0.26 0.96 14 16 18 19/1 92.0 103.2 104.8 106.0 8,000 0.45 0.99 3

2 3

• All tests were performtd on Soil type SP from boring no. DM-9.

B t.4 Y (PCF) d 11 100 110 120 130 140 80 90 o

I 0

J.:

O io-

{

O I

O O

20-e O

O 3

0 s..

O KEY:

o 0 1973 OSTERBERG SAMPLES F

O 1979 OSTERBERG SAMPLES (frozen) g g

l J

40-et ee

~

O r

{

O O

h gw

. eee O

O I

F o

O e

I l

70 O

1 OO 80-e L

oO 1

00 O

.e 100-l VARIATION OF DRY DENSITY WITH DEPTH ommes a moone 25 FIGURE 5

[:

10.0 LIQUEFACTION ANALYSES 10.1 General The liquefaction analyses performed for the LAC 8WR site in the past were based on test borings and laboratory data from the D&M investigations of 1973 (Ref. 1). As mentioned in earlier sections of this report, the findings of the 1973 studies were evaluated by NRC in 1978 under its Safety j

Evaluation Program, and several questions were raised regarding the fac-I tors of safety under the design SSE.

D&M also reevaluated its earlier j

fincings as a result of the NRC review usir; a rrent state-of-the-art methods. Although D&M concluded that the fact >rs of safety against lique-7 faction under the design SSE remained unchanged, there was agreement among NRC, WES, D&M, and DPC in the following:

l a.

" Undisturbed" sampling in the cohesionless soils was necessary.

b.

In situ dry censities must be estimated with greater accuracy l

using " undisturbed" samples.

~

There was a need for development of continuous standard penetra-c.

tion "N" values under carefully controlled conditions.

d.

Cyclic shear strength parameters of the liquefiable soils had to be obtained by performing cyclic triaxial tests on " undisturbed" samples.

e.

Estimates of the cyclic shear stresses resulting from the design SSE must be made by performing a one-dimensional wave propagation analysis.

f.

The seismicity of the LACBWR plant site and the potential for liquefaction under an acceleration level wnich realistically rep-7 resents the seismicity of the site must be analyzed.

~

With consideration of these requirements, a limited but carefully con-trolled field and laboratory investigations program was undertaken.

Using the data developed in these investigations, detailed liquefaction analyses were performed.

~

10.2 Liquefaction Potential There are two basic approaches for evaluating the liquefaction poten-tial of a deposit of saturated sand when it is subjected to earthquake loading.

The first approach uses the information available on the perform-ance of various sand deposits during past earthquakes.

This approach is essentially empirical, and the response of soil to earthquake loading is O

26

Y l

not evaluated by any direct means.

Simplified methods of analysis, with known limitations, have been proposed by various investigators.

Also, a large number of factors that significantly affect the liquefac-tion characteristics of a givea sand have been recognized and may be studied in detail to confirm the conclusions of such an' analysis, f

In the second approach, stress conditions in the field are evaluated 3

by using an analytical technique, such as the one-dimensional wave A

propagation analysis.

Laboratory investigations are conducted to deter-mine the cyclic sSear stresses required to cause liquefaction at various d

depths. At a given depth, a factor of safety against liquefaction can be evaluated by dividing the cyclic shear stress required to cause liquefaction by the cyclic shear stress induced during the design earth-quak e.

T

_fj Methods based on these two approaches were used to assess the liquefaction potential of the granular soils at the LACBWR site.

l

.:)

10.3 Evaluation of Liquef action Potential, Approach 1 10.3.1 Simolified Procedure (Procedure 1).

In the first approach,

]

the procedure recomended by Seed (Ref. 7) was used to estimate the cyclic shear stress required to cause liquefaction.

The cyclic shear stress induced during shaking was computed by the Seed and Idriss Simpli-fied Procedure (Ref. 6). The following steps are used in Procedure 1:

~

Convert the "N"* values from the Standard Penetration Tests to N) a.

values (N) is the penetration resistance, corrected to an effec-2

~

tive overburden pressure of 1 ton /ft ) using the relationship:

~

Ny=CN (")

where:

~

C = 1 - 1.25 log 6 /5 N

c 1 2

&c = effective overburden pressure (tons /ft )

2 51 = a constant equal to 1 ton /f t.

• N = number of blows required to advance a standard split-spoon 12 inches into the ground, when driven by a hammer weighing 140 pounds dropping a distance of 30 inches.

27

b.

Based on a collection of data from actual field performance

~~

and a few additional site studies, the lower bounds for the cyclic shear stress ratios that cause liquefaction in the

}

field and which correspond to different N values and magnitudes y

of earthquakes have been established (Ref. 7).

Using this 7

relationship, the N values can then be converted to the cyclic y

d shear stress ratios, T/d, required to cause liquefaction for the design earthquake.

cl c.

Compute the cyclic shear stress ratio at any depth in the ground that is induced by the design earthquake (Ref. 6) using the relationship:

av/#c = 0.65 (amax/9) I"o/#c) r T

d l

where:

}

Oc

= effective overburdea pressure on sand layer l

a

= maximum acceleration at the max ground surface 2

(ft/sec )

o

= total ir.itial overburden pressure on 2

sand layer under consideration (tons /ft )

i r

= a stress reduction factor varying from d

a value of 1.0 at the ground surface to a value of 0.9 at a depth of about 30 feet.

T av

= average cyclic shear stress in the sand 2

layer under consideration (tons /ft )

2 g

= acceleration due to gravity (ft/sec ),

d.

The lower bound cyclic shear strength values that are obtained from Step "b" can then be compared with the average cyclic shear stresses obtained in Step "c," and the liquefacthon

~

potential at various depths can be evaluated.

SPT(N) values from the recent O&M investigations were plotted as a function of depth (Figure 2). Average design N values were chosen

}

for different depths and were converted to corrected blow counts (N ).

y Relative boundaries between " liquefaction" and "no liquefaction" condi-tions for variou's magnitudes of earthquakes corresponding to ground y

1 surface acceleration levels between 0.10 g and 0.20 g were drawn using the data and principles presented by Seed (Ref. 7).

Figures 6 through 11 28 l

ll-I f

I:

_T 0.6

[

Z em tiU u

I 0,5

$b 3C 4

• Y Jw

.}

5a b$

0.4 Z

T es

.j

-o

/

~

z 0.3 og

• D" d

9 h 0.2 i

Es

/

max.10g

=

a

=

EE

'l tis og o

ds U

i 0

10 20 30 40 50

=

l.

MODIFIED PENETRATION RESISTANCE Ng - blowshoot l

!I_

T CORRELATION BETWEEN FIELD LIQUEFACTION BEHAVIOR OF SANDS FOR LEVEL GROUND CONDITIONS AND PENETRATION RESISTANCE 1

l6P I

g FIGURE 6 29

S e

.I.'

d

.i 0.6 em O

[

$5 7

o.s O,.

O toj O

a a m b.J

=

F<

0.4 l

8s ae 5g o3 l

l 0 4 lb*E 9 h 0.2 l

55 f

=g

...i2 w

h b3 A

]

O O

a t-Y5 0

00 10 20 30 40 50 MODIFIED PENETRATION RESISTANCE Ng - blows / foot 3

I CORRELATION BETWEEN FIELD LIQUEFACTION BEHAVIOR OF SANDS FOR LEVEL GROUND CONDITIONS AND PENETRATION RESISTANCE I

}

i D A M E S B M O OftM 30 FIGURE 7

~.

e 5

2 3

0.6 I

z i

9m a

uU Y

+

<n g

O.5 i

1

$d De a8 d

0.4 at i

ce J

Eo 5'z l

P 0.3

)

/

i L

og f

c D"$

L E

t e L

e 5 0.2 H-

< C; c:@

ma x" 149 a

u

+

• +

0.1 p

I F

J 00 10 20 30 40 so I

MODIFIED PENETRATION RESISTANCE Ng blows / foot L

w

[

CORRELATION BETWEEN FIELD LIQUEFACTION BEHAVIOR OF SANDS FOR LEVEL GROUND CONDITIONS AND PENETRATION RESISTANCE 1

t ommes a moons l

FIGURE 8

[

31

-~

1 m

0.6

]

z i

O u.

H m

o

$5

~

w 0.5 3

• C D 3@E s

~

N 0.4 zez cw I

o m

~

$mz 0.3 UE

/

e b**a

=-

sw e 9 h 0.2 r<G E

~

{O A

smax.16g

=

3 0

]

0.1 3

~

6 es a-

$5 0

to 20 30 40 50 MODIFIED PENETRATION RESISTANCE Ng Wwh l

tJ H

CORRELATION BETWEEN FIELD LIQUEFACTION BEHAVIOR OF SANDS FOR LEVEL GROUND CONDITIONS AND PENETRATION RESISTANCE m

e m

o I

un = = = a m oo = =

32 FIGURE 9

+

L.

O I

1 1

i 0.6 2

i O u.

hN

[

0.5

~

o*

38 pm l-E N 0.4

~z>

cb 3

5E

@z 0.3 UE

/

• • w w e 9 h 0.2 x

y m3 X

~

x max.18g

=

a

$t g

~

55 0.1 Y

mJ uz Ub og h

a 0

lb 20 30 40 50 MODIFIED PENETRATION RESISTANCE N1 blows / foot

_I i

l" CORRELATION BETWEEN FIELD LiOUEFACTION BEHAVIOR OF SANDS FOR LEVEL GROUND CONDITIONS AND PENETRATION RESISTANCE I

t T_

g 33 FIGURE 10

L C-lL

~

PL J

IL i

i l

1 0.6 2

9 u.

30 Y

.7 m"

0.5 D

• L oC 3C a?

N o.4

~

EE ew H5 gm

<2 0.3 uq

/

l efE a-s m

% e 9#

0.2 w

n-sa o o ]

hh

.o[]

amax.20g m@

=

C c,

\\

]

95 E

U l

o 0

10 20 30 40 50 MODIFIED PENETRATION RESISTANCE Ni hs#wt CORRELATION BETWEEN FIELD LIQUEFACTION BEHAVIOR OF SANDS FOR LEVEL GROUND CONDITIONS AND PENETRATION RESISTANCE I

I i

DAM EES 8 MOOR E 34 FIGURE 11

[.

F show such boundaries on which are plotted LACBWR plant site data of N values corresponding to certain cyclic shear stress ratios induced

+

y by the respective earthquakes of different magnitudes.

The SPT(N)

~

values, the corresponding N values used to compute the strength, the y

cyclic shear strengths, and the cyclic shear stresses cog uted using s

the Simplified Procedure, and the resulting factors of safety at different

[

depths for various acceleration levels are presented in Table 3.

The stresses and strengths are presented as functions of depth for the

~

six acceleraion levels in Figures 12 through 17.

f.

Data in Figures 12 through 17 and Table 3 show that the site does not liquefy at acceleration levels less than or equal to 0.12 g at any depth.

As the acceleration level increases from 0.14 g to 0.20 g,

~

the capths susceptible to liquefaction increase from 20 to 30 feet to 10 to 40 feet.

10.3.2 Japanese Procedure (Procedure 2). A procedure being used in Japan (Ref. 8) also falls under the general category of Approach 1.

The procedure for cog uting the cyclic shear stresses is the same as

{

described in Step "c" above using Seed and Idriss (Ref. 6) simplifications.

~

The estimation of the cyclic shear strength is as follows:

l-Estimate the relative density of the liquefiable soil using the a.

relation developed by Meyerhof (Ref. 10) based on laboratory tests performed by Gibbs and Holtz (Ref. 13):

D * = 21 N/(F + 0.7)

[

r y

f where:

D*

= estimated relative density r

1-N

= blow count from SPT

~

d

= effective overburden pressure at the y

2 depth of interest (kg/cm ).

{

b.

Estimate the cyclic shear.

?n,th using the appropriate equation:

O f - 0.225 log 10 (050/0.35)

R(

+; 01 l

for..m5 0 5 0.6 m

[

50 or l_

R

= 0.0042 D * - 0.05 r

50 5 1. 5 m for 0.6 m 1 0

[

35

[

~

~

.- ~

m-m

+-a u.__,

m TABLE 3 SU" MARY OF LIQUEFACTION ANALYSIS APPROACH 1, PROCEDURE 1 Av.e g e Cyclic Shear Stresses, Cyclic Shear Strengths, and Factors of Safety for Various Accelerations

• 0.10 9 a

- 0.12 9 a,,,

- 0.14 9 a,,, - 0.16 9 a,,

- 0.18 g

a.,,,

0.20 g a,,,

m,

• • ston N/"I

'ov i

rs

'av i_,q,t n g i

rs

'av i

rs

'av i

rs

'av 1

rs

'av i

rS 10 6/H 73 138 1.89 88 138 1.57 102 127 1.23 118 127 1.08 132 127 0.96 147 127 0.36 20 6/6 145 167 1.15 174 174 1.00 203 140 0.73 232 148 0.64 261 148 0.57 290 148 0.51 10 10/9 213 317 1.49 255 317 1.24 298 292 0.98 341 292 0.86 383 292 0.76 426 292 0.69 40 14/tl 270 525 1.94 324 494 1.52 378 494 1.31 432 463 1.07 486 463 0.95 540 463 0.86 50 25/17 301 1,005 3.34 361 968 2.68 421 894 2.12 482 894 1.85 542 856 1.58 602 856 1.42 60 l t./ 2 0 328 1,371 4.18 194 1,327 3.30 459 1,283 2.80 525 1,239 2.36 590 1,239 2.10 656 1,239 1.89 70

.12/16 14 3 1,256 3.66 411 1,206 2.93 480 1,155 2.41 548 1,105 2.02 617 1,105 1.79 685 1,105 1.61 80 35/15 16 3 1,317 3.63 435 1,317 3.03 508 1,260 2.48 581 1,203 2.07 653 1,203 1.84 726 1,203 1.66 90 17/14 389 1,414 3.63 467 1,349 2.89 545 1,285 2.36 622 1,285 2.07 700 1,285 1.84 778 1.285 1.65 100 40/12 409 1,349 3.30 491 1,278 2.60 573 1,207 2.11 655 1,207 1.84 737 1,207 1.64 Blu 1,207 1.48

• T

= average cyclic shear stress from Seed & Idriss Simplified Procedure (Ref. 6).

3y cyclic shear strength based on corrected blow counts and recorded cyclic behavior during earthquakes.

T =

Factor of safety (FS) = (cyclic shear strength) + (average cyclic shear stress).

l l

CYCLIC SHEAR STRESS / STRENGTH (psf) 0 20,0 40,0 60,0 800 1000 1200 o

1400 i

's N

N3\\

\\

\\

20-A's N'A*s R

_ 40-A,~_'

~~,,'%

=

9 s%

h

• N O 60-g'N %p

/

/

/

R

\\

\\

\\

80-k

\\

\\

hI I

t 100-d i

l KEY:

l e--4 AVERAGE CYCLIC SHEAR STRESS (SIMPLIFIED PROCEDURE) 0-4 CYCLIC SHE AR STRENGTH BASED ON PENETR ATION RESISTANCE L

COMPARISON OF CYCLIC SHEAR STRENGTH APPROACH 1 PROCEDURE 1 (amax =0.10g)

I I

l oa==s e moon.

11._..-.------,

fMMM 9C 37 a

El '

=

I 1

CYCLIC SHEAR STRESS / STRENGTH (psf) o 200 400 soo 800 1000 1200 1400 o

's N3 b-.

s' P

M-s's s

N s N

F

_ 40-D-

,'~

L

~_'~~,

Y

% ~,'~

k[

w*

~,s

~ 'P so.

/

/

I N

80-

~

1

/

/

r soo_

d L

KEY:

E W AVER AGE CYCLIC SHEAR STRESS (SIMPUFIED PROCEDUREl t

O--O CYCLIC SHEAR STRENGTH BASED ON PENETRATION RESISTANCE 4

1 x

b COMPARISON OF CYCLIC SHEAR STRESS AND STRENGTH APPROACH 1 PROCEDURE 1 (a

=0.129) max s

DAM ES B MOORM 38 FIGURE 13 I

I..

il CYCLIC SHEAR STRESS / STRENGTH (psf)

E Y

Y

' N

'Y

[

0 s.N

\\

1 m

(

20-

's

'j N

N N

%'~~'~

40-

=:

~~'~s c

s 5

m'*%s 60-Y

/

/

(

s

's\\

80-

\\

\\

L b

/

/

d too-KEY:

9--e AVER AGE CYCLIC SHEAR STRESS (SIMPLIFIED PROCEDURE)

O--O CYCLIC SHFAR STRENGTH B ASED ON PENETR ATION RESISTANCE I

I h

I COMPARISON OF CYCLIC SHEAR STRESS AND STRENGTH i

APPROACH 1 PROCEDURE 1 (a

=0.14g) max l

DAMES B MOORE

(

39 FIGURE 14

=

~

f CYCLIC SHEAR STRESS / STRENGTH (psf)

'~

0 200 400 600 800 1000 1200 1400 0

~

\\

\\

1 20 A

=

ss N

'l M'N

_ 40-

~s E

w%'%~

=

'~g I

'w%

g g

'*ws ~~,

f 60-

/

'N

\\

80-S

}'

\\

\\

f

/

/

1 100-d 1

KEY:

g 9--e AVER AGE CYCLIC SHE AR STRESS (SIMPLIFIED PROCEDURE)

O---O CYLIC SHE AR STRENGTH BASED ON PENETRATION RESISTANCE w

4 lu E

L-COMPARISON OF CYCLIC SHEAR STRESS AND STRENGTH

)

APPROACH 1 PROCEDURE 1 (amax= 0.16g) l Y

Y u

j b

1 Y

l names a moosen e

40 FIGURE 15

I 1

CYCLIC SHEAR STRESS / STRENGTH (psf) 6@

800 1000 1200 o

14,00

\\

=

M-kN N

\\s s

N

_ 40-

'*%ss I

f if

'%s w

N o,

s~~,

/

,/

s

\\

N 80-k

~

\\

\\

/

/

100-KEY:

(

o----4 AVERAGE CYCLIC SHEAR STRESS (SIMPLIFIED PROCEDURE)

O---o CYCLIC SHEAR STRENGTH BASED ON PENETRATION RESISTANCE r

i 1

i COMPARISON OF CYCLIC SHEAR STRESS AND STRENGTH i

APPROACH 1 PROCEDURE 1 (a

=0.18g) l max i

l p.

l DAMas 8 MOOMM

(

41 FIGURE 16

[

[

i a

I CYCLIC SHE AR STRESS STRENGTH (psf) j 0

200 400 6p 8@

1000 1200 14,00

'N 2

\\

\\

N-k

^

N Nh

\\

_ 40-M~%

'*%s 3

'~~s

%~s'N I

%s'~

g s 7 60-

/

?

/

/

l k

\\

\\

9 k

t, 80-N

\\

,/

T g e,:-

KEY:

H AVERAGE CYCLIC SHEAR STRESS (SIMPLIFIED PROCEDUREl

<>--O CYCLIC SHE AR STRENGTH BASED ON PENETR ATION l*ESISTANCE 1

COMPARISON OF CYCLIC SHEAR STRESS AND STRENGTH APPROACH 1 PROCEDURE 1 (a

=0.20g) max

)

b FIGURE 17 I

42

i.

where D*

= estimated relative density from Step "a"

r 7

D

= particle size in m corresponding to SO

_I 50 percent on the grain size curve and l

R

= cyclic shear stress ratio required to L

cause liquefaction (triaxial test conditions).

c c.

Apply suitable corrections to R to obtain R, the corrected cyclic shear stress ratio required to cause liquefaction.

c R

= (C ) (C ) (C ) R 1

2 3

L 7.j where C

= 0.57 (to convert triaxial test conditions 1

to simple shear field condition) 1 C

= 1.3 to 1.5 (to account for N

= 5 rather 2

eq than N

= 20 used in Japanese study

,,,pq

_f C

= 1 (to account for differences in failure 3

strain criteria **).

By comparing the estimated values of cyclic shear strengths from the Japanese procedure (Ref. 8) and the average cyclic shear stresses

~

from the Seed and Idriss procedure (Ref. 6), factors of safety against potential for liquefaction can be estimated for different depths.

~

The cyclic shear stresses which were calculated under Procedure 1 were I

also used under Procedure 2.

The relative densities were estimated using SPT(N) values (Figure 2) and 0 values (Table 1).

Table 4 presents 50 1

the estimated relative densities, the estimated cyclic shear strengths, the calculated cyclic shear stresses, and the resulting factors of safety at various depths for different accelerations.

The stresses and strengths at differer.t depths for all the acceleration levels considered are plotted on Figure 18.

The data on Table 4 and Figure 18 suggest that there would be no liquefaction susceptibility under earthquakes producing ground surface accelerations of less than or equal to 0.16 g.

Under accelerations of 0.18 g and 0.20 g LACBWR site soils between depths of 20 to 40 feet may experience liquefaction.

I 1

• • The 5 to C percent double amplitude shear strain used in the Japanese studies w.s very close to the initial liquefaction criterion used in thi<,

D&M study.

Therefore C ~ 1 was used, 3

l l

43 l

1

~

-m ue~a tm-m-m m,

-w o - g-

,- w a --- '

TABLE 4

SUMMARY

OF LIQUEFACTI0tl AtiALYSIS APPROACH 1, PROCEDURE 2 Average Cyclic Shear Stresses and Factors of Safety for various Accelerations

• __

a,,,

= 0.10 g a,,, = 0.12 9 a,,, = 0.14 g a,,,

= 0.16 g a,,,

= 0.18 g a,,,

= 0.20 g i (psf)

'av fpsf[

FS

'ay f.S

'av fS

'av

[S

'av FS,

_' a v TS DenttL,{ft) 10 4h 161 73 2.21 88 1.83 103 1.57 118 1.37 132 1.22 147 1.10 20 41 222 145 1.53 174 1.28 203 1.09 232 0.96 261 0.85 290 0.77 10 44 165 213 1.72 255 1.43 290 1.23 341 1.07 383 0.95 426 0.86 40 53 494 270 1.83 324 1.52 378 1.31 432 1.14 486 1.02 540 0.91 50 66 745 301 2.47 361 2.06 421 1.77 482 1.54 542 1.37 602 1.24 60 75 885 328 2.70 394 2.25 459 1.93 525 1.69 590 1.50 656 1.35 h

70 67 1,005 343 2.93 411 2.44 480 2.09 548 1.83 617 1.63 685 1.47 80 66 1,145 163 3.16 435 2.63 508 2.25 581 1.97 653 1.75 726 1.58 90 65 1,092 389 2.81 467 2.34 545 2.00 622 1.76 700 1.56 778 1.40 100 64 1,349 409 3.30 491 2.75 573 2.35 655 2.06 737 1.83 818 1.65

• r

= average cyclic shear stress computed using Seed & Idriss Simplified Procedure (Ref. 6).

av

= cyclic shear strength estimated from relative density (Japanese procedure), (Ref. 8).

T Factor of safety (FS) = (cyclic shear strength) + (average cyclic shear stress).

0.5

• • D

= relative density based on D = 21 11/(d

+.7)

(Ref. 10).

r p

y

Il il CYCLIC SHEAR STRESUSTRENGTH (psf) 0 200 400 600 800 1000 1200 14p i

KEY:

AVERAGE CYCLIC SHEAR STRESS (SIMPLIFIED PROCEDURE) 20-CYCLIC SHEAR STRENGTH BASED N

0--<>

ON RELATIVE DENSITY AND GRAIN N

SIZE (JAPANESE PROCT: DURE)

N I

_ 40-h E

N 2

N s s.

I N N o.

s \\

o so-N N

sb N N

N 80-

/

I i

i i

I 5

d s I.

I.

+.

's s

2 Y

.1 I

Y

'N 300 y

l COMPARISON OF CYCLIC SHEAR STRESS AND STRENGTH APPROACH 1 PROCEDURE 2 (a

=0.10g to 0.20g) max l

l D M M EES B M O Ostur 45 FIGURE 18

[

10.4 Evaluation of Liquefaction Potential, Approach 2 Approach 2 uses more rigorous methods and site-specific data from sophisticated laboratory results. A seismic response analysis was

[

performed to estimate the stresses, strains, and accelerations at different depths within the soil profile resulting from SSE loadig at the LAC 8WR

[

site. Also, several liquefaction tests were performed on undisturbed samples to define their behavior under cyclic loading.

=

10.4.1 Soil Model Used in the Response Analysis.

Based on a review of the data from the most recent investigation, a representative, idealized

{

soil profile was established for the one-dimensional wave propagation analysis.

This idealized soil profile corresponds to an average surface elevation of +639 feet.

Table 5 presents the idealized soil profile and the soil properties that were used in the resoonse analysis.

The upper 135 feet of the soil deposit were divided into 12 sublay-ers.

Detailed descriptions of the soils encountered at the LACBWR site are presented in Table 5 and on the boring logs in the Appendix.

10.4.2 Soil Properties Used in the Response Analysis.

The soil properties

{

required for the wave propagation analysis are unit weight, shear modulus,

~

damping ratio, and coefficient of earth pressure at rest.

a.

Average values of unit weights based on field and laboratory test results were used in the analyses (Table 5).

b.

In general, the shear modulus of a soil is influenced by several I

variables, including effective confining pressure, veld ratio, stress history, degree of saturation, soil structure, amplitude of strain, and frequency of vibration (Ref.14).

The in situ f

shear modulus can be estimated by reviewing data from the geophysical survey.

to low strain levels (approximately 10 g modulus corresponds This value of shea y

percent).

Shear moduli corresponding to other strain levels can be determined r

from strain-controlled cyclic triaxial tests and resonant column tests.

The extensive field and laboratory investigations of different soils conducted by independent researchers have y

generally established shear modulus versus strain relationships

)-

of soils (Ref. 6).

The shear modulus versus strain relation-ships of sands at the LACBWR site were developed by considering the generalized trends from the published data, the results of strain-controlled cyclic triaxial tests performed on recon-stituted samples in 1973, and the relative density estimations based on SPT results.

l 46

[

F

s s__ m

- gw w

y a

M MN M

N O

TABLE 5 GENERALIZED S0ll PROFILE AND MODEL FOR ONE-DIMENSION?.L WAVE PROPAGATION ANALYSIS

\\

Elevation Depth Shear (ft)

(ft)

Design N Modulus valve T Wet (pcf).

D,,,

K y...

g gg,gy

+639 0

Cround surface elevation +619 Ilydraulic fills brown fine-115 376 to-medium sand with occasion.

6 45 43 al fine gravel, trace of sitt 120 1,162 619 20 Cround water +627 to +631 Cray-green fine-to-medium 121 sand with occasional fine 1,660 gravel, trace of sitt, 1.yers 6-14 48 45 of clayey sitt 12e 1,eso 599 40 (Dottom of reactor vessel +610 to +618)

Brown fine-to-medium sand 126 66 55 2,550 with occasional fine gravel /

coarse sand, crace of silt 14-36 133 2,795 579 60 (Bottom of piles a e x.

+580)

Btown f l ie-t o-med i um sa nd 559 80 with occasional fine gravel /

133 122 3,L37 3,325 coarst sand, trace of silt 30-40 132 533 100 3,537 130 69 57 3,738 Fine-to-coarse gravel and brown fine-to-medium sand 134 with little sitt 90 6,244 519 115 Brown fine-to-medium sand with occasional fine gravel /

134 90 70 5,273 coarse sand, trace of silt 499 135 Dedrock

• Based on field measurements.

0.7) 0.5 (Ref. 10); laboratory D

• • Based on D 21 ff/(5

=

+

tests, and Ref. 11.

r v

r o**From expression G = 1,000 K2 (U )0.5 based on data from Ref. 15.

m

,m, i

m,wo--

om

---m-w*-""

Based on the reported results in the literature (Ref. 15),

the shear modulus, at low strain levels of coarse grained soils, can be expressed by the equation G

= (1000) (K ) Ib )

2 m

2 G

= shear modulus (lb/ft )

2 6

= effective mean confining pressure (lb/ft )

m K

= constant for a given compactness of 2

soll.

The values of K used in the analysis are presented in Table 5.

s 7

The shear modulas varies nonlinearly with strain level. This variation was assumed to follow the pattern of average data

[

on the coarse-grained soils found in the literature (Ref. 15).

The nonlinear strain dependence of she r modulus that was used in this analysis is presented in Figure 19.

c.

Most of the parameters discussed in relation to shear modulus have an opposite effect' tin'the damping value, which increases with increasing strain amplitude, decreases slightly with 2

increasing ambient stress, and decreases with increasing void ratio.

Strain-controlled cyclic triaxial tests and resonant column tests on undisturbed samples are necessary to define experimentally the variation of the damping ratio with strain

~

level.

However, for the purposes of this study, it was con-l'-

soils at the LACBWR site, both in magnitude and in variation sidered satisfactory to assume that the damping ratio of the with strain level, were similar to the average results found in the literature (Ref. 15).

These values are the average values obtained from the experimental investigation performed by several independent researchers on typical sands. The strain-dependent values of the damp'ng ratios for typical sands which were used in this response analysis are presented

~

in Figure 20.

(The damping ratios measured experimentally in the laboratory during the 1973 D&M investigations were also reviewed before choosing the design values).

d.

A value of 0.45 was assigned for the coefficient of earth

[

pressure for all the granular soils.

r 10.4.3 Design Earthquake Used in the Response Analysis. The horizontal L

component of a digitized acceleration-time history was used as the

]!a input motion at the surface of the soil deposit.

The corresponding accelerogram is presented in Figure 21.

e The duration of the design earthquake was assumed to be 15 seconds, and a range of maximum ground surface accelerations of 10 to 20 percent of gravity was used, based on the recomendations of NRC.

{

48 I

\\

I

~

1.0 0.9 -

r L

L y

0.8-t'

=

0.7-g t

5 L

2 N

G 0.6 -

5 e

=

0. 5 -

.~

s w

S 0.4-I-

2 e

L.

z<

m W

0.3-0.2-r 1

L l

0.1-r lu 0

y 0.0001 0.001 0.01 0.10 1.00 10.00 I

l SHEAR STRAIN, / -PERCENT u

l 1

1 TYPICAL REDUCTION OF SHEAR MODULUS WITH SHEAR STRAIN L

(coarse grained soils) k L

(SEE D & IORISS.1970) ommes a mooses 49 FIGURE 19 i

l

'l\\1I

,I fl l

l

,l 1

0 7

9 1

S, S

t RD I

D E

E S

(

9 3

S 1

D NA S

D T

E N

i T

E g

C A

R R

j E

P UT A

N I

S A

R R

O T

F 7

S O

R I

A T

~

, R 2

E A

H S

R G

N

~

l P

MA D

1 3

n

, 0 1

3 w

4 n

0 1

w 5

0 5

0 5

0 5

0 1

3 3

2 2

1 565 a. i o E$ y n.

a3ImU O I0 35 I

2$Mg l

11llll1l

s Sog.xsm3 6 - NOl1VH3'1333V o

o o

o N

o N

o

.g

+

+

o L

i i

o 1

_Q l

w l

J l

o

'n D

= _ _ _ -

b y

9

a 4

]

e E

1 c

o

^^

2

.c

'.E o

U

• g

~

o w

_o o

s w

z Z

y 2

z p

O e

~

lEo

- um 0

_o g

h 4H 2

1 Og u

g O

o

_o I-e f

^^

w m

m w

N

m. -_

h w

o e

l o

I o

b b

o

• o I,

n 9

o*

o i

+

+

60t. xew,

6. NOl1VU 37 330V ommes a mooseu 51 FIGURE 21

3 10.4.4 One-Dimensional Wave Propagation Analysis. A mathematical F

model was used to evaluate the response of the soils at the LACBWR site when subjected to the SSE loading.

This model is based on one-u

{

dimensional strain-compatible shear wave propagation through a layered system.

Each layer in the system is assumed to be isotropic, homogeneous,

{

and of viscoelastic behavior (Ref. 16).

A computer program developed by Schnabel et al. (Ref. 16) was modified by D&M to include additional input and output. The nonlinearity of the shear modulus and damping ratio is accounted for in this program by the use of equivalent linear properties.

This computer program (Ref.17) was verified for various practical problems, certified in accordance with quality assurance requirements, and used to analyze the soils at the LACBWR site.

The average shear stress levels in the stress histories obtained by peforming one-dimensional analysis were computed assuming the ground water to be at 10 feet below ground surface.

This represents the average condition; the groundwater level actually fluctuates slightly.

The i,

average cyclic shear stresses computed by performing one-dimensional analyses are plotted as functions of depth for various acceleration levels on Figure 22.

10.4.5 Cyclic Shear Strength.

The next step in Approach 2 is to deter-mine the cyclic shear strength of undisturbed samples obtained from various potentially liquefiable layers.

Fifteen samples, representing four depths of the soil profile, were chosen for stress-controlled j

cyclic triaxial testing using standard procedures described in Section 9.6.

Figure 3 shows the envelope of particle size curves for the samples used.

The results of these tests are summarized in Table 2.

The test e

1 results were plotted on a semilogarithmic plot to define the relationship between stress ratio and number of cycles required to cause initial liquefaction (Figures 23 through 27).

10.4.6 Conversion of Irregular Stress History Into Equivalent Uniform Cyclic Stress Series.

In Approach 2, the calculated cyclic shear stresses are compared directly with those required to cause liquefaction of representative soil samples in the laboratory.

It is usually more convenient to perform laboratory tests using uniform cyclic stress 52

E D

I.

l.

L i

l CYCLIC SHE AR STRESS / STRENGTH (pif) r 0

~

I KEY:

i o--4 AVERAGE CYCLIC SHEAR STRESS (ONE-DIMENSIONAL ANALYSIS) l

~

N s

\\

0---O STRENGTHS BASED ON CYCLIC TRIAXI AL TESTS ON UNDISTURBED

\\

SAMPLES 40-I

's l

u

=

g N

=

F[

N I

w s

l

%s l

Q so-

's

%. 's i

p N '% 's 80-

's s r

y r

300-5 1.'n $.

1..

c

')

"g 120-2 o

140-F Il COMPARISON OF CYCLIC SHEAR STRESS AND STRENGTH APPROACH 2 (a

0.10g to 0.20g) max names e moos=

FIGURE 22 c7

r 000 I

0 I

1 i

I i

I i

I i

E N

O m

i f

I T

C sp A

C F

o i

0 E

0 f

2 ip U

4 E

6 QI R

0 1

L U

0 S

5 0

L S

0 t

I 0,

A i

1 E

r i

Rf :

I 1

I i

9 Y

I IT

- P1 i M 2 I 8

N T

G -

i D N 6S

I 1N I

m i

IRNP Y i

F i

GN: E I

R

^y NI HD O

=

F T T

3 OOER S E e

BCDD E

E E L F C

1 i

f Y

S 2

E C

L O

F 1

C T

Y O 6 C

R1 F

E 1

0 H

0 O

B T i

f 1

R MP u

i I

E UE I

B ND i

M i

I U

S 1

e I

N U.

SO t

e R N i

E i

I V T S

OE I

T T

i f

A R

SSE m

i 1

R 0

T i

\\

t A

i a

S m

i R

n u

i E

i jei%1116 5

H S

i CI a

L i

e C

i 2

Y 2

0 C

\\

=

t i

R i

S 1

0 8

6 4

2 i

1 0

0 0

Y" t

i e E '9H<1 NwK$

i b ]<

Q3ImW 3 goj, 2

lln 5 5, 3

ll j1llill il ll lj l'

i'll i

-[

p W

B TI 00 0,

0 1

Y H

DSS W

{

e TL ETAEEKTY WB T

ASI AU i

CSEOTED IEVT TIW N

P i

DRR ELO OI

,D RN AL N TUEA H ISC TVE T

i S

V E

E NE TEH C

f IT VN A

J' LT s

E GWI B p

VDISOTUA F

F 0

RllEH AO OE E

N U l

i 0

UAD

,V C 5

f C

NRCIEL U

O 2

s VRE E A T 'U A Q

p

R E

3ESS U

E 6

E OSAV I

TPEWON EC" L

C R

0 T UEB OPHOHON 1

NUTLCCIOB" 0

i U

1 0

L K

e S

0 1

S 0,

A 1

I i

E g

i 9 Rf :

T t

Y E

T I

E P7 E

i M 3 I N

~E e

D GS I

N1

I 3N R

i GN: E O

NI HD I F T F

M RNP Y T

p E E S

OOER L E

. BCDD F

CY7 C 3 S

M L

F O E

C O T Y

1 C

.R 3 0

F E

0 O

B H Q

E UE R

M T 1

P B

ND M

S M

U 2

N U S

O R

N E

D VT E E S

DU OE M

i RL

~

I C V T T A A A

S "B R

i IDT" S

W

~

S S

Eo E

TL o

\\

R 0

T i

N

' 1 S

R i

\\

A i

\\

E i

o H

\\

Il4 iIIiiIII 5

S i

N a

\\

C i

M i

\\

I L

\\

C i

s\\

0 Y

3 0

C

=

M i

SR M

1 0

8 6

4 2

0 0

0 0

0 0

1 8"

1 s e".9$c OwEU

• bd 0>Eae @ E oa' llIlll g,

jNS $

h M

0 M

i 1

0 i

0

' 0 i

i M

i N

i M

i O

f I

sp TC 0

A i

0 F

0 fs 4

p E

M 6

U E

R 0

U Q

1 S

4 0

LI i

S 0

0 i

E 0

L 1

t i

9Rf :

' 1 M

i DGS A

Y P2 I

T i

M 5 I T

I 4N NI N1 I

i GN:E R

M i

BCDD E E NI HD IF T i

RNPY O

OOER F T SE L F E

C 2

S Y5 C

L O

C F T Y

O W

1 C

1 R4 0

F

(

0 O

E H B T R

E MP

')

B U E M

N D i

U S 3 i

N O

i RN U

S O E

T VS 7

IO E T

TA f

R S

R S

E 0

R T

1 T

i o

S T

i R

i A

C i

o iliI 5

E H

S 7

C LI r

6 C

2 Y

0

=

C m

R S

c 1

o 0

8 6

4 2

0 1

0 0

0 0'

0 I

8

$'t" o'e a e 0 E t t

r "b 3 gNIa8 3 Io!.

l

)

I

g f

ne m

m I

0 i

0 i

0, I

"1 0

w i

l i

f N

sp O

I 00 T

0 C

b i

8 s

f p

A E

8 F

I R

0 E

1 U

U S

6 Q

S 0

E 9Rf :

0 L

I 1

E L

t 0

- P2 Y M

GN: E N

. M

' 0 A

9 T GI

. D 7S

' 1 I

IN T

8N I

INI HD I

F T RNPY OOER R

f_

BCDD F

O T

~L SE EE L F M

Y 9 C 2 S

E C O L

F C

1 T

Y O 7 C

R8 0

F E H 0

O B T v

1 R

MP n

B E

UE ND N

U M

U S 4 v

SO r

RN E

=

V T S

OE T

I T

A R

S S

E R

0 T

1 S

R o

A E

H

, IiIi1 l t \\ :s 1u!

5 S

C I

L C

_ 7

_ 3 Y

o C

_ n

_ s 0

8 6

4 2

0 1

1 0

0 0

O-0 Y"

t dE4cc het i

I3 t<

0II! a lj.

l l

ll1I1ll1 l

1 ll

00 0

0 1

R E

B M

U N

N 0

O 0

C 0,

I R

i 1

B A

F LI N OO SI T D C N A AF E

S Y

E TI Q U

L C

SI Y

NL C

E L 0

F D A 0

O 1

I F

T o

ER OI B

S IN M

T U

CO N

ET F S FE EL D

G C Y

O N

N N

I C N

OO U

U WF O

O B

B N

R H

R E

E S

P W

U, L, N fg P

c E

V 0

R 1

U C

/o x

R Y

L M

A L

M L

U IF o

C S

I LU

\\

A RD Y

H 1

0 8

6 4

2 0

1 0

0 0'

0 0

d" n E 6G; $sg

?]t<

O)I l aIoOI w

2' oEm l

lt l

m applications than to attempt to reproduce a representative field stress history.

Therefore, it is necessary to convert the irregular stress history that is actually developed during earthquakes into an equivalent uniform cyclic stress series.

l There are three basic methods by which this conversion can te accomplished. However, it has been shown that the procedures used 7

1 in this step of the analysis have little effect on the final analysis (Ref. 7). Based on the results of a statistical study of the representa-f tive numbers of cycles developed during a number of different earthquake motions, a convenient basis for selecting an equivalent uniform cyclic stress series for earthquakes of different m&gnitudes has been presented by Seed (Ref. 7). According to Seed, for earthquake magnitudes between 5 and 6, the number of equivalent cycles, Neg, is approximately 5, corresponding to an average cyclic shear stress, Tav, of 65 percent 7j of the maximum shear stresses.

Therefore, the maximum cyclic shear stresses that were obtained by performing a one-dimensional wave propaga-tion analysis were multiplied by 0.65 to obtain the average cyclic shear stress at any point.

10.4.7 Correction Factor.

The cyclic triaxial test does not directly 7

i simulate the simple shear conditions actually induced during an earth-quake. Also, the effect of multidirectional shaking is not included in this testing.

As a result, the stress ratio obtained in the cyclic l

triaxial test is higher, and a correction factor, C, is applied to r

modify these values.

For normally consolidated sands (K ~ 0.4), a g

j value of 0.57 is censidered appropriate for Cr (Ref. 7), and the stress ratio causing liquefaction in the laboratory is multiplied by 0.57 l

to account for the field conditions.

l Figure 22 repretents the summary of cyclic shear stress computation using the one-dimensional analysis and the cyclic shear strengths from the laboratory tests.

The stresses plotted are 65 percent of the maximum shear stresses to correspond to an average condition.

The cyclic shear d

strengths were obtained by following the procedures mentioned below.

Figure 27 is a summary of all liquefaction test results.

It can be j

seen that threc distinct liquefaction curves can be drawn on the various data points--an uppe 1ound and lower bound for natural materials below 1

i 59

E' I

the hydraulic fill material and an average for hydraulic fill material.

Three stress ratios corresponding to these three curves can be chosen for a given number of cycles, N For N f 5, the three possible eq.

eq relations between confining pressure and the cyclic. shear stress required to cause liquefaction (cyclic shear strength) are plotted on Figure 28.

The shaded zone shows the scatter of data for natural soils below the hydraulic fill. However, the nonlinear effects of the relationshlP between confining pressure and the cyclic shear strength can best be estimated by selecting the stress ratios from data on each indiviitual test presented on Figures 23,24, 25, and 26.

These four tests represent four different confining pressures ranging from 2,000 to 8,000 psf-A design strength curve was drawn on Figure 28 by selecting the four different stress ratius from Figures 23 through 27.

It can l'e seen that the design curve chosen represents a lower bound of strength to almost 4,000 psf of confining pressure.

(This range of confining pressure represents the crucial depths up to 50 feet where liqueraction q

potential is of primary concern.) A field strength curve corresp"nding 2

to 57 percent of the laboratory triaxial strength curve has been etrawn on Figure 28.

It is this curve that was used to determine the st,engths at various depths.

10.4.8 Factor of Safety Computation.

The cyclic shear stress re'luired L

to cause liquefaction at a particular depth is found from the field strength curve of Figure 28 by reading off the ordinate correspon, ling

)

to the confining pressure at that depth.

The variation of the cy,.lic shear strength, the induced average shear stress (obtained by the one-l dimensional wave propogation analysis), and their ratio (that is, the factor of safety against liquefaction) with depth are summarized in Table 6.

The cyclic shear stresses and strength are also presentnd as a function of depth on Figure 22.

Table 6 and Figure 22 show that even with a very conservative interpretation of strength data, no lique-faction is predicted up to an acceleration level of 0.20 g.

10.4.9 Discussion and Conclusions.

During the current investiga, ion, the liquefaction potential at the LACBWR site was studied using a simpli-a fied approach and a rigorous approach.

In the simplified approado stresses were computed using empirical equations and strengths we "

60 t

O ST E

S E

T L

A O

I O

1 l

I i 1

I i i I

l l

i l i I d

X O

S 8

A T

I SE R

)

T N

T M

O N

C I

O T

I R

I L

F WL D

OL N

0 C

D I

0 NEF O

'0 Y

L C

7 UBC C

O I

OSL N

L BDU E

O RNA L

IF EAR L

D S

WSD F E=

E I

T\\

ONY 7

C V

S S.

0 S

LOH I

R E

0 b

A L

['<//

U 0

T U

Cx 6

B E

M V

A H

R H T E

O R

T RWL U

Y G G R

D FOL C

DLF H

H N N U

I E

E S

E T

R S

NBC G S T

)

R T U

f E

I OSL N T S S 0

8 0

P R

BDU ECS IE D N d

NA R

G 5

P I

R LT L

c AR T

I C

ES ES E

F G

P D SY L I

A F

N PNY NCI D

UOH GMX l

E I

SO A R

N I

I ERR U

I F

DFT S

0 S N

M I

l 1 l

l I I I l

'0 E

0 O

R 4

C P

G D

N I

N IN A

F H

0 N T

0 O G

'0 C

N 3

E l

I l

I I

/

R l

i l l

TS R

0 A

l i

0 E

0 2

H S

C I

L CY 00 C

'0 N

1 E

E

/

W T

E B

0' O

~

0" N

0 0

0 0

0 n

0 o

O 0

5 0

3 2

2 0

s I

T A

L E3 IH 5C a 5$= o3 o E

R g

Eme @ lE" l

ll b

li 3

I I

E E

M E

O O

M M

M Q

g TABLE 6

SUMMARY

OF LIQUEFACTION AtiALYSIS APPROACli 2 Average _ Cyclic Shear Stresses and Factors of Safety for Various Accelerations

• a

= 0.10 g a

= 0.12 9a, = 0.14 g a,,,

= 0.16 g a,,,

= 0.18 g a,,,

= 0.20 g

.,lin f )

'av W"U D ep t h _(f_t ).

FS

'av FS

'av FS av FS

'av FS

'av FS 10 150 72 2.08 86 1.74 101 1.49 114 1.32 128 1.17 141 1.06 20 250 134 1.87 163 1.53 189 1.32 214 1.17 238 1.05 26 2 0.95 10 350 194 1.80 233 1.50 268 1.31 302 1.16 340 1.03 367 0.95 40 460 244 1.89 290 1.59 332 1.39 371 1.24 411 1.12 450 1.02 50 590 284 2.08 339 1.74 387 1.52 433 1.36 479 1.23 525 9.12 60 730 322 2.27 384 1.90 439 1.66 490 1.49 539 1.35 587 1.24 Q

70 060 356 2.42 420 2.05 478 1.80 532 1.62 5R5 1.47 639 1.35 no 1,090 381 2.76 449 2.34 512 2.05 573 1.83 633 1.66 695 1.51 90 1,240 407 3.05 482 2.57 550 2.25 620 2.00 684 1.81 750 1.65 l

• t

= average cyclic shear stress = (maximum cyclic shear stress from one-dimensional analysis) x (0.65).

av

= cyclic shear strength = (triaxial cyclic shear strength) x (0.S7).

T Factor of safety (FS) = (cyclic shear strength) i (average cyclic shear stress).

I estimated using past experience during earthquakes at various sites that liquefied and also using relative densities.

In the rigorous approach, stresses were computed using a one-dimensional model and wave propagation response analysis.

The strengths were measured by performing cyclic triaxial tests on undisturbed samples.

The following conclusions were based on these analyses:

Using Approach 1, Procedure 1 (Seed and Idriss stress and a.

strength based on SPT, N values), no liquefaction is predicted up to a maximum acceleration level of 0.12 g.

The potential I

for liquefaction is suggested for various maximum surface acceleration levels as stated below:

a depths prone to liquefaction max 0.10 g none 0.12 gnone 4

0.14 g 20 to 30 feet 0.16 g 20 to 30 feet o

0.18 g 10 to 40 feet 0.20 g 10 to 40 feet.

f b.

Using Approach 1, Procedure 2 (Seed and Idriss stress and strength based on relative densities), no liquefaction is predicted up to a maximum acceleration level of 0.16 g.

The potential for liquefaction is predicted for various maximum acceleration levels as stated below:

a depths prone to liquefaction g

max 2

0.10 g none 0.12 9 none l

0.14 g none 0.16 g 20 feet 0.18 g 20 to 30 feet 0.20 g 20 to 40 feet.

1 c.

Using Approach 2 (stresses from one-dimensional wave propagation analysis and strength from stress-controlled cyclic triaxial

]'

tests peformed in the laboratory on undisturbed samples),

no liquefaction is predicted up to a maximum acceleration level of 0.20 g as stated below:

a 63

?

~

a depths prone to liquefaction max 0.10 g none 0.12 g none u

0.14 g none 0.16 g none 0.18 g none 0.20 g 20 to 30 feet.

The rigorous analysis made duririg the current investigation is relatively more accurate than all other analyses made at the LACBWR

[

plant site. We believe that a high degree of confidence can be assigned to the rigorous analysis made during the current investigations for the following reasons:

a.

The test boring and sampling program was performed under care-fully controlled conditions using state-of-the-art techniques.

b.

The undisturbed samples were drained and frozen at the site before transporting for storage and were kept frozen until just before testing (practically eliminating sample disturbance at the site),

c.

The frozen samples were carefully packaged ano transported by D&M field engineers to minimize any possible sample disturb-ance during transport, d.

State-of-the-art testing techniques were used to determine the in situ densities and the cyclic shear strengths of samples.

e.

All the field and laboratory investigations were subject to stringent quality assurance and quality control requirements of D&M, DPC, and NRC.

In summary, given our present knowledge and understanding of the seismicity of the region and the behavior of soils under dynamic loading, it is our opinion that there is little threat of liquefaction at the LACBWR site under a maximum acceleration level corresponding to a realis-tic design SSE that can be assigned to the site.

64 i

l

Rt 8

11.0

SUMMARY

OF LIQUEFACTION ANALYSES AT THE LACBWR SITE The D&M analysis of 1973 (Ref.1) was conservative and concluded that the factors of safety against potential for liquefaction under the design SSE at various depths were adequate.

WES performed a very conservative analysis (Ref. 3) and concluded that the minimum factor of safety was close to unity under a 0.12 g ground acceleration. As a result of D&M's review of its past work and the WES report, and reevalua-tion of the various analyses, it was concluded that the factors of safety were indeed adequate.

However, there were certain questions that were raised by NRC regarding the lack of test data on undisturbed samples and the lack of continuous standard penetration test results.

I Since the existing data did not satisfy these new concerns, DPC decided to perform modest field and laboratory investigations and modest analyses to verify the earlier findings cn liquefaction potential.

As a result of the new state-of-the-art investigations performed at the LACBWR plant site, it is now concluded that the LAC 8WR plant site has an adequate factor of safety against potential for liquefaction under any realistic design SSE that can be assigned to the plant site.

However, in the absence of an NRC decisio' regarding a design SSE and n

l a corresponding design acceleration level, a range of acceleration between 0.10 g and 0.20 g was assumed and factors of safety were estimated.

l The minimum factors of safety are listed below for the different acceleration levels:

l

' max Depth (ft)

Factor of Safety 0.10 g 30 1.80 l

0.12 g 30 1.50 0.14 g 30 1.31 0.16 g 30 1.16 l

0.18 g 30 1.03 0.20 g 20-30 0.95 l

Based on these results, it can be concluded that the threshold liquefaction resistance at the LACBWR site occurs for a design SSE I

which yields a maximum ground surface acceleration greater than 0.18 g and less than 0.20 g.

65

I REFERENCES 1.

Dames & Moore, Geotechnical Investigation of Geology, Seismology, and Liquefaction Potential, Lacrosse Boiling Water Reactor (LACBWR)

Near Genoa, Vernon County, Wisconsin, October 1973 (prepared for I

Guif United Nuclear Fuels Corporation).

2.

Dairyland Power Cooperative, Application for Operating License I

for the Lacrosse Boilino Water Reactor, 1974 (submitted to the U.S. Nuclear Regulatory Commission).

I 3.

Marcuson, W. F. and W. A.

Bieganousky, liquefaction Analysis for Lacrosse Nuclear Power Station, U.S. Army Engineer Waterways Experiment Station, December 1978 (submitted to the U.S. Nuclear Regulatory Comission).

4.

Dames & Moore, Review of Liquefaction Potential, Lacrosse Boiling Water Reactor (LACBWR) Near Genoa, Vernon County, Wisconsin, March 1979 (submitted to the U.S. Nuclear Regulatory Commission).

5.

U.S. Nuclear Regulatory Commission, letter of April 30, 1979 (Docket No. 50-409), to Dairyland Power Cooperative's General Manager.

6.

Seed, H. B. and I. M. Idriss, " Simplified Procedure for Evaluating Soil Liquefaction Potential," Journal of the Soil Mechanics and

~

Foundations Division, ASCE, Vol. 97, No. SM9, Proceedings Paper 8371 (September 1971), pp.1249-1273.

7.

Seed, H. B., " Soil Liquefaction and Cyclic Mobility Evaluation For Level Ground During Earthquakes," Journal of the Geotechnical Engineering Division, ASCE, Vol. 105, No. GT2, Proc. Paper 14380 (February 1979), pp. 201-255.

8.

0hashi, M., T. Iwasaki, F. Tatsuoka, and K. lokida, "A Practical Procedure for Assesing Earthquake-Induced Liquefaction of Sandy Deposits," Proceedings--Tenth Joint Meeting U.S.-Japan Panel on l

Wind and Seismic Effects (Public Works Research Institute Ministry I

of Construction, 1978).

I 9.

Marcuson, W. F. and A. G. Franklin, " State of the Art of Undisturbed l

Sampling of Cohesionless Soils," Proceedings--International Symposium on Soil Sampling, Preprint, Singapore (July 1979).

10. Meyerhof, G. G., " Discussion of Gibbs and Holtz Paper," Proceedings g

of 4th International Conference of Soil Mechanics and Foundation y

Engineering, Vol. III, London (1957).

l

11. Marcuson, W. F. III and W. A. Bieganousky, "SPT and Relative Density in Coarse Sands," Journal of the Geotechnical Engineering Division, ASCE, Vol.103, No. GT11, Proc. Paper 13350 (November 1977), pp.1295-1309.

66 1i X

l

=

s d

12.

Silver, M.

L., Laboratory Triaxial Testing Prc.cecures to Determine the Cyclic Strength of Soils, NUREG-0031 (U.S. :'.aclear Regulatory Commission, June 1977).

~

13. Gibbs, H. S. and W. G. Holtz, "Research on Determining the Density of Sands by Spoon Penetration Tests," Proceedings of 4th International

[

Conference of Soil Mechanics and Foundation Engineering, Vol. I, London (1957).

0

14. Hardin, Bobby 0. and Vincent P. Drnevich, " Shear Modulus and Damping S

in Soils:

Design Equations and Curves," Journal of the Soil Mechanics and Foundations Division (American Society of Civil Engineers,

.l July 1972).

a 15.

SW-AJA (Shannon-Wilson and Agbabian-Jacobsen Associates), Soil Behavior Under Earthquake Loauing Conditions (Union Carbide Corpora-tion 1972), (submitted to U.S. Atomic Energy Commissior.).

r I

16.

Schnabel, B., J. Lysmer, and H. B. Seed, SHAKE, A Computer Program for Earthquake Response Analysis of Horizontal Layered Sites, Report No. EERC 72-12 (Earthquake Center, University of California, 1

1972).

17.

Dames & Moore, SHAKE--One-Dimensional Wave Propogation for Multi-Layered Soil System, Computer Program EP55 (1975).

f d

i 1l h

1 l

67 l

l

s F

l

+

L l

l I

l l

i APPENDIX l

BORING LOGS j

1J I

I l

I 4

I G

d

,,, 1 1

KEY T0_ LOG OF B0 RINGS LEGEND:

12 L1 INDICATES DEPTH OF STANDARD SPLIT SP0ON SAMPLE.

INDICATES NUMBER OF BLOWS REQUIRED TO DRIVE STANDARD SPLIT SPOON ONE FOOT IN STANDARD PENETRATION TEST.

INDICATES DEPTH OF SPT SAMPLIrlG ATTEMPT WITH NO RE-O C0VERY.

INDICATES DEPTH OF RELATIVELY UNDISTURBED SAMPLE 08-p TAINED WITH OSTERBERG PISTON SAMPLER.

I i

INDICATES THAT SAMPLE TUBE WAS PUSHED INTO S0Il BY I,

HYDRAULIC PRESSURE.

b INDILATES DEPTH OF DISTURBED SAMPLE OBTAINED WITH l

S OSTERBERG PISTON SAMPLER.

a b

l l

ELEVATIONS REFER 10 THE USGS MEAN SEA LEVEL DATUM.

APPR0XIt1 ATE LOCATIONS OF BORINGS ARE SHOWN ON PLOT PLAN.

CLASSIFICAT!0tl SYMBOLS REFER TO UNIFIED CLASSIFICATION SYSTEM, PLATE A-2.

DISCUSSION IN TEXT IS NECESSARY FOR C0f1PLETE UNDERSTANDING OF THE SUBSURFACE l1ATERI ALS.

n D A M ME S 8 M OO pt EE PMUTJ M.9

i i

SOIL CLASSlFICA E

GRAF MAJOR O/V/SIONS SYMBC 8

• e t *' '

g*4e G8Avil CLtam GaastLS e s t o,'

AND m'*se

• • ee GaavitLv E

5 0.L S C0 asst

,,s*

CR Atht L hN

$0at $

33,g gg g,,

,g s '.*'e'*g aos '...

e 8

, ee.a...e as,

e_e

e*

aste ca ee0@

et me e sd ot y

e e 'g'p.

s se SANO CL f A ss SAh3 amp west ce

.e O*85

$aNDY E

SCILS eest

• • a e es %

e*

ee'te et is i "

kJ! *111 **** *e e

see s.e es s at eest e ne e se%

$ANQ3 wiTM res(3,'

es rosest e s ec-.see s t. ass t seems p

e=

1. Ausa es eens s e

', ',,./,e*

• s a se rt

. :. p*:

, r MN F8ht g...,

g,,,,

A"O GR Atht0 Lgu v.a.

se CL AFS SOILS e...

ll' 1

sc a t T=**

se %

SILT 5 y

C s'

• • 't***

• s AND g,g

,,,,g L.ta.6LJ

'a==

=

CLAYS ese s.s et sJs

,s,,.,-

HIGMLY OR G ANIC SOILS a

N OT E S:

a cmA svmeoLs aat usto to soCatt e0 notated ctassar a a weita s=own oss te Soems Locs. TWC FOLLOWe8e ItEEe

• cms 71aCY OF CO9 tent sants asso tag attaftwt ComiseC**

CoatSrvt sOtts D

Iasesommatt swt anoss f *etioGT'= ps Fle) vtetsWT LisiU.23 Vf t

~

L8' ' '

I Leos soi f 02s TO O s et ends 8* '

l wtDeunt STrF 0 s To to Otost stFF to 70 2 0 wn Ot*t vtev sT7 toto 40 stand 6et arte imam 4 0

'4 fa l.

i

TION CHART I,

t/

LETTER GRADATION CHART TrPicAL DESCRIPTIONS t gyugot

' *. ~..... <.........

m re., 5 w o.;;

artem ser a.n o..~

• u**.."'

I u.e s ei.

. u...rie, u.t Sas.

I

~~

o.......

( '.

sp u.*

lO o..

. uao.

o.,

u ! u**

087

• • 0*

F*0

• .3

• 7 l...

,a GM

-o...

m-

,a e

r;r

<...s.

oc n-w r,.-

u..

.., v.. u..

sa sP i.

sM n...n.

no n. -o-n 0

PLASTICITY CHART SC u..s.

no.. pan.. -own uovo umr e

e

.m so ao w

so

'o e

e oo n.

m.......-

i l

n.e.u.n.... w. n.. <. n.

yg nn n.

m

. __ _J,..._,;.

n 1

..c. n...........n..

..e, r

i f

1'

...u.. u..

CH CL u.....

9 n. u.

u.

(

.v

_ a.-,

p 9

1 y

t O,-

,,u........nn,...

.o 6

a b

zu V --

MH

.. u..c..u n. =.*<*"."o**.

E1 g*

CL u

o

=

n N

f

.s l

.g s.

1 l

71 s-gn

..w e c... e. ~:=

l

'/

-~

k MH&OH

{E M

....c...,

r.,

n...

e re O

k g

,_--_y.

-a

~;

~

oH

• "***"..o*"...*.*.,u*n"

- E ML 8OL n..

l l',-

I

_____0 et..,

.v l

PT l

l MS O TD Of SCT S 08 Cat $so lf fait (g33 soit3

,9 0 t 55 10.L S T (St a.

f 4110,Os.1..M.LT se f ma.ss.4-D TC ed f.. Scal S.au*LE S.

O 5TKE, asso SOE D(e.5.TY fsoas rgr57-8-

CKYa t

1 UNIFIED s' OIL CLASSIFICATION SYSTEM t

t h; '

samese e neoosem l

FIGURE A 2 i

t l

BORING DM-7(CONT'D)

BORING DM-7

~

%m ?

SURFACE EL EVA TION

• ese rent 5 e, N u

3$ gg $g LOCAT/ONe cE=oA.wiscomsm

$ $g $g e gW 82l gWat a a svueol.s otscarrion 2

A 2

util at a 3 svueol.s o tscn w rio n 8~~

O,'JN"4 W O; ii.,i C 28-[8'

~

2 wttscA=i* #1 G M f [t[ caAv[L 1-27 -

SP l

-S

-90 caADIE W TH TBACI 0F F!ht

,3 p

(,

GRAY [L 2-a]

caAo:e utva linsts (* rist 28 -

sA43 Wifw 9FE slLT y

r]ng fg (CApst caArtt AmD ticaf SANt 1

Fist to MtCluM SAND WITH TaACE OF

• 9 3-

-10 caAcim wiru taACt or coAnst 29 -

' 93 '#S 3 utt

,, 3

,e, SP yyjif5L5 6' '"'

g,,

t a

4-30 P

q

-I5 p

~ 100 soon~ n gp S-h J/

I 'I

>94 6-

-20 32 -

' #03 '#3' ' ' D%

casal% caAr-catte ON CLAYET 5ILT cAADl% OUT CAaA cGA

((4 CLAv[T $tLi

• Ta TAACE

,8 8

ggy y

-25 11 0

1. ~

34 '

~

cAAr.catts fint sAto stia vaACt or siti

-30

'^

,3 3

caArts snow 4 blTH MEDIUM $A43 1003 3 10 -

36 -

E

' ##O

$P caAoiw wifn motum sA=0

-33 l

caso:w cuv.cartu w s 11 -

F l 37-

1. 1. ~

'20

-40 can:g run n 3 13 -

39

$ ' '3 0

-45 14 -

p 40 fcP Of DOCK S081% C39L(f(0 A7 A 0(PTM OF 15 - _gg ng.o rggr om s.n-1s 30 1 hAtta igvtt a[ConDf3 AT A CEPTM 1E OF 7.0 F[tf on 5 29-79 16 -

-55 a

3p l

17-r I

18 -

\\

-60 cacts.:T. taACt er (cAast 1

38 3

$Ag, f eat er Fist caA.[L.

5'El%En Os rat:As(xs ma'[at At

-65 l

l 20 -

f e

t1 21 -

I

-70 s:;T. reest sac. '/uti 3,

can:% cc 22-23-

~

24-R

.gg utAC % ;Ta 781!t CI St LL 33 e F ea:p{ 4Ti 25 -

E

-83 LOG OF BORING o....---

BORING DM-8 BORING DM-B (CONT'D)

~

$, ?

y

$URFACE EL EVA TION

• sne FEET Ns5 y

LOCATIONe GENOA.wsC0kseN f (g $g

$ fu $g

$$ gWoN d $

SYMBOLS DESCRIPTION A

2 g

sL W 2

NY $N $$

$YMBOLS DESCRIPTION o

o

. m s e,u r au n o nst gs

- 85 9 M BA0W4 Flti YO Mf DIUM $A40 1

27-5 cuer% wiin inAtt 0F Ft4t

-90 a 9 caAutt A=3 tinsts ce tt Art, s

SP 2

ssti 28-J

-to sp cuat=c w:T* ut F i=E cAAvu, 29-

-95 I

TRACE OF COAR5[ $A%D Fjg[ ig (033$[ ggAVEL AMO BR0b s Flat TO LL AVEl $!LT GRAtlE OUT q

MEDIUM 5AMD blTH TAACE OF $1LT A*

30-t.

-100,,n 3 6:p

-15 cuci% wtTis Occasim ca;nst 5

,4 GAAVEL

'5 s-

-20 Guain Gui-catte w Ta tuct 32-

-105

$I iin 3 5 3 0F 5tLT A_

DARs GRAY CL AY(T $1LT WITH $fpt Flh[ $AMS

(

I~

33-890W4 FINE TO MEDlUM $AND WlIN TRACE OF

-25

-110 GRADIC WITH ALT [RMA!!% L Av[R$

g, g

0F FimE 5A43 AN3 L Artes OF 34

$1LTT CLAY, WITH TRAC ( OF caGantC5 GAAY-GR(tu Flat TO MEDluM 5AkD WlIN TEAC[

OF 11LY 9~

-30 35-

- Ils 1C 3 gaafe 3 to -

3g.

-35

-12 0 Sp

'2 m

es s f,.

37, A$]%A

~

133 WDfE WT 6

14 3 g

3, 3

13 -

39-

[ 45

~ 130 14 -

40k

3 TR OF ROCn B3RIC COMPLET[0 AT A D(PTH OF 131.5 FEET 04 5-22-79 f 'a - -50

.ATER t[ vfl RECORDCD AT A D[PTH 29 3 0F 8.0 F((T 04 5-22-79 16 -

-55 17-M 3 sp 18 - -60 sat suMC af 8'

3 Gu :% m:Tm 'BA:t CF C3Aa5E 5AkC fg-gQ -

29 3 l

21-

-70 m: e sa:e

,, 3 22-J 23-

~

is a 24 -

~'

jg l

25 -

?)

- 85 LOG OF BORING om.... - oo-.

M

4 a

e F

9 BORING DM-10 BORING DM-10(CONT'D)

E ?

C SURFACE EL EVA TION. sn ute s E ?

O m

s ZQ fg g

LOCATION

• Genon w<sconsen

&Q fu $g y

4" AW 2

(b

$$ sw$$ o$$

SYMBOLS DESCRIPTION SYMBOLS DESCRIPTION 2

> ~..

ms.s a

s,s,~'

a. s 26 4' 00 O

O 3 m t

'S

.m I

27 I u

5 i 90 m,

2-28 -

3-90 29- - 95 SP i a:n.. w us e w, z.:

M m 7

uvi 4. v.t ua,i >

3p 4-30 -

-100,,

i aa.n to paq 4 t, as i w..

-15 anci% mit :=Att 'a u-n i W;0. it(C A51(AA1 P:l(tk <4 3,

y.

F i%t t. ras [t 1

I 32 4 -105 6-

-20 ung, una 3, 9

f tht to (fasst Lang[t aus grN, r ::;r T,

g W

4(Dltpt $AND >] f te t] Tilt %lg ?

,,f 7-te, c;a,.c.,tts r at sasa aso cta t, ut '

33-a gp h

- 110 soo,v s 4 :p-

.n..

5

-25 L

34 -

Et p q' '.

8-

' #L44 f l%E TO *[ Dita 'AND elTe is Act 4.4 CAAt GRith F !h[ 73 PifDlyM SAhD sif u TRACT til f u coasst saso, sAct or uit 9

35- - /IS 62 3 10 3 10 -

36-canDiv.ifie 0(Casic^at ts:vu I

-35 GsA01%..Tu MCA$1M fl[(Et

3 or rtut cnnutt g;.

3y.

SP h 125 toor,

1. 2 ~

3#~

-4O A:, e e:sst < 2v + o *

,,g ;,, si.,3 ute:S a7 it 1 i

fi I3 -

39 1

-45

' '30 ll 40il I4 -

II

'J Cs axe Brel% CDP' Pit'ic AT 4 DtPT* Of f3 50 132.5 firi 0% 5 30-19 22 1

.a![a g[ytt af tceDID AT A OtP?w of 12.0 f tti 09 5-33-79

-55 c.a.:..

17-N.

tut c8 ccmt 5.0 18 -

-60 se,

19 -

-65

.v( g-: (,u-5 1 20 -

22 1'

21 - ~70 33 9 22-8 1 - 75 23-4 21,

24 -

-80 so,

25 l

l 8

. g3 LOG OF BORING DAMES B MOORE PLATE A-6

4

.a f

BORING DM-ll(CONT'D)

BORING DM-Il

~

Em E O

SUR** ACE EL EVA TION

• s3e rnet EsN O

fQ fu $g LOCMION* ctuos.wesconsm (Q fu $g e

2 2

h gw $$

SYMBOLS DESCRIPTION oN b gWON $ $

SYMBOLS DESCRIPTION 0-

- 0 L

q ee, %.

.mm.

26 -

'83 cuois wiTn rout or Coast o 3 s

siw to more sano mTT* occasionat sana is.,

PIE!!5 Or Tit! CRAv[L I-f 27-I

~S

~**

e,

.s 2-28-3'

-10 29-

~95 y

4' 30-

-t5 3 0 34 3 5-31 6-

-20 32-

-105 caanis utT TaAct or cou$t

,, 3 5Ana

.1 Fin [ TO COAR5[ GAAV[L AND taw 4 Ilbt TO y-33-GS*

M[Djun 5AND WITM TRACE 03 SILT e

m.p

.g3

-110

-, tr 4 g

6-3# ~

PP1 GP 9- -30

1. ~

"I'0 si n e

to -

36-I*I "E8 '# I'" "' '" '"( t '

8*0"s'it t I

_y3 caAOIC Guf Gaith "I2O

,4 3

12 1 GRAVEL. CSAA$t $Ac GaA31=6 0UT 37 GRA01% Wifw $0Mt COAa5E $AND 12 -

38-

. gg5 1

_4g

,; 3 33 3 SP 13 -

sp 39-

-45 13 0 3'

14 -

40-IS -

41 4

.g33

. f ss

.g 23 3

• 6 808!% CMLETED AT A OCPTM OF I

136.0 FEET On 6-2 't

/6 -

waitt ((Vil B[CCRDED AT A DEPTM CF 12.0 Ftti ch 6-2-79

-55 su::v. c'*

uct a Ccust Sae,

• o 1

17-Tant er FN ;asett I

16 - -60 rtst cuvtt saa::u ocf 5

19 -

-65 snxat.. cut:w saca 21 -

-70 n,

22 -

I l

F 75 ast we cu: w a 24 -

-a0 25 -

l l s5 LOG OF BORING ommuns a moos==

PL ATE A'-7

_ - _ _ _ _ _ _ _ _