ML20137C370
| ML20137C370 | |
| Person / Time | |
|---|---|
| Issue date: | 10/24/1985 |
| From: | Jaggennath B NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Rager R JACOBS ENGINEERING GROUP, INC. |
| References | |
| REF-WM-39 NUDOCS 8601160297 | |
| Download: ML20137C370 (41) | |
Text
DISTRIBUTION: M WM r/f WM-39 NMSS r/f
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OCT 2 41985 WMEG r/f i
REBrowning MBell WM-39/BJ/10/22/85 JGreeves
-I-BJagannath MTokar MNataraja TJohnson Ron Rager, Geotechnical Manager Miller Jacobs Engineering Group, Inc.
LHigginbotham 5301 Central Avenue, Suite 1700 JBunting Albuquerque, NM 87108
~
MKnapp PDR Dear Ron; In accordance with your request of October 4,1985, the final draft! of the Slope Stability section of the DOE's UMTRA Design Manual has been reviewed.
The attached copy has the review coments in the margin; there are no major comments. Also attached are copies of site characterization, ground settlement, and liquefaction sections of the final draft of the Design Manual with review comments in the margins.
Please call me at FTS 427-4629 if you would like to discuss the review coments with me.
Sincerely, f
f BanadJagannath,ProjectManager[
Engineering Section Division of Waste Management, NMSS
Enclosure:
As stated I
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LPDR 8601160297 851024 Distribution:
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PAE:4MINARY DRAFT SLOPE STABILITY y fi Alabildy du MM
1.0 INTRODUCTION
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In order to assure the long term stability of the stabilized' tailings hiles, the long term static and earthquake loading conditions aredete-Med.
In addit on,fshort term static and seismic loading conditions of the embankment slopes and si constructfbi gnificant cut slopes will be required in order to assure ity of the proposed designs. SWlW 4 667 Mb a l 'V ? "
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-Wienal,/ lope stability analyses are performed for UMTRA sites using d
conventional slope stability analyse These methods of analyses include circular and non-circularflimiting equilibrium analyses, wedge analyses, and infinite slope analyses. The method of analysis used will depend on the aswal site conditions analyzed.
Various computer programs are available for conducting these analyses, and seismic conditions can be analyzed by using a pseudo-static approach. For small slopes or slopes' he g p ~
having a simple statigraphy, the use of slope stability charts may be y
iJppropri ate.
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.h hh',For the pseud tic analysis [a seismic coefficient (k) is selected M
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/ yF,@i l based on the
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The minimum
> value of k u/erived site acceleration (see Chapter sed at any site is 0.10.
Above this value, k is derived by taking two-thirds of the derived site acceleration.
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2
O 3.0 ANALYSIS 3.1 SELECTION OF CROSS SECTIONS Selection of the cross section(s) to be analyzed are based solely on engineering judgement backed by reviews of the site characterization da-ta. Several cross sections based on actual site stratigraphy and proposed pile configuration may be evaluated or a composite cross section combined web the highest embankment section and the most critical layering configura-tion may be used.
Typical c-iteH ' """"^'- hen developing profiles include:
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Embankmentandfoundationstratigraphy.
o o Proposed slope configuration (typically five horizontal to one verticalslope(forthetailingsembankment).
o Identification of weaker soil layers.
o Selection of material properties for all soll layers (see Section 3.2).
o Seepage and ground water conditions.
3
gyha4304 f used 3.2 DAT/i REDUCTION
~
Existing and new laboratory est data ill be evaluated in order to determine impiet strength parameter inte e stability analyses. All data available will be considered in the,aealy:;s.
A discussion of the deriva-
.N tion of strength parameters will be &redff'or each sTte and wit 1 be-9 "* *
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presented in the RAP document. Appropriate density, moisture content, triaxial compression, direct shear, cone pentrometer and standard penetra-tion test data will be reviewed.
Engineering judgement will figure strong-p ly in derivir:g input values. Whenever possible, published data will be reviewed to verify themr= ter election.
NAVFAC DM7.1 (1983), Lambe
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and Whitman (1969) andlVick (1983), will be used along with other texts, if required, to perform verification.~
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S Suitable strength parameters will be selected for input into total j
and effective stress analysgs. The following table will t~..el, be used as a guide in the selection of design strength parameters (Lambe &
Whi tman, 1969).
Table 3.1 Choice of total versus effective stress method of stability analysis Situation Preferred method
- 1. End-of-construction w'th satur-5.-analysis with p= 0 and c= s.
ated soil; construction period short compared to consolidation time
- 2. Long-term stability :nd i. ring c,f-analysiswithporepressures
-cewaettetivu nau s i N.y given by equilibrium ground water canditiont
- 3. End-of-construction with Either method: Co.,f(fromUUtests i
partially saturated soil; or2,pplusestimatedporepressures construction period short compared to consolidation time i
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e 3.3 CONDITIONS ANALYZED Slope stability analyses are performed on major cuts and fills associated with the tailings pile, appurtenant earth structures (both temporary and pemanent), and surrounding natural slopes which may impact, or be impacted, by construction of the embankment.
Table 3.2 presents the criteria used for judging acceptable slopes analyzed using conventional slope stability analysis.
Table 3.2 Guioelines for minimum slope stability safety factors Design Minimum acceptable Situation factor of safety During construction stability 1.3 End of construction static stability 1.3 a
End of construction seismic stability 1.0 Long term static stability 1.5 L
staHe P t Longterm {floodstability 1.2 a
a Long term seismic stability 1,1
. b e., d4Aig n e.l O A' See Section 3 for a discussion of seismic design coefficients. d, g 70ther conditions not typically found on UMTRA projects,,but may arise in the design of appurtenant structures will teep 5iGihonly accepted minimum f actors of safety (e.g., earth dams may require sudden drawdown or partial pool analyses as recommended by COE, 1970).
For slopes subjected to high accelerations (design accelerations greater than 0.30g) other methods of dynamic analyses may be used in order to verify slope stability. Slopes not meeting the minimum safety factors are appropriately redesigned in order to meet these standards.
5
t COE (U.S. Amy Corp of Engineers),1970. Engineering Manual, EM 1110-2-1902, Stability of Earth and Rockfill Dams, Washington, D.C.
Lambe and Whitman, 1969. Soil Mechanics, Massachusetts Institute of Technology, Boston, Massachusetts.
NAVFAC (U.S. Department of Navy, Naval Facilities Command), 1982.
DM - 7.1, Alexandria, Virginia.
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i FINAL DRAFT SITE CHARACTERIZATION - GE0 TECHNICAL
1.0 INTRODUCTION
The purpose of geotechnical characterization of UMTRA sites is to define the geotechnical conditions of existing tailings piles, foundation soils and proposed borrow sources. The stratigraphy and physical properties of materials composing the stratigraphic units are characterized. Stratigraphy is determined usihs so(ew I'1N by h;;"; ::::M:h from boreholes, and test pits, and static-cone penetration tests.
Piezocone or other field and laboratory testing may also te used to define stratigraphy. Material properties are determined by laboratory tests and field tests. The nature and extent of investigations will vary from site to site. This chapter describes exploration methods and tests used for processing sites, disposal sites and borrow areas.
ound wate characterization, which is closely related to geotechnical s*We characterization is described in matert.I, Chapter Determination {of radon barrierlac site soil and tailings tenuation and emanation coeffic is described in Chapter _.
C'etailed procedures used in conducting the geotechnical field investigations are contained in the Jacobs' Albuquerque Operations Manual, Volume 3.
These standard operating procedures are compiled into a Field Technical Representative Manual which is provided to each field engineer or geologist prior to connencing field investigations.
1
The programs outlined in~ this Chapter are the minimum effort considered a
sik ch rnh<sg.4 m necessary to define site characteristics.
Each d * "' ; program must be designed to fit the data needs and characteristics of individual sites.
/
4 2
2.0 ARCHIVED DATA In order to assess the data needed at a specific site and to avoid duplication of efforts, available data for the particular site wi11 b AvadaMC e reviewed.
This will include review offinformation on existing boreholes and t est pits, site and regional geology, laboratory test data and any other app which may influence site characterization.
ata These and other data will be presented in a summary of site characterization efforts S
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3.0 ALTERNATE SITE SELECT 10N A Sean*
@ alternate sitesse&estmen ee will be conducted for UMTRA sites.
The purpose of this is to identify alternate sites for disposal of tailings if stabilization in place is technically unsuitable or too costly. The culmination of this and other studies will, as part of the NEPA process, result in the selection of the preferred alternative.
In order to provide preliminary subsurf ace information to evaluate alternate sites, at least three borings will be completed at the processing site and the alternate sites.
If subsurf ace information exists for a site, no drilling will be performed. Testing and sampling will consist of SPT's at five foot on center. Rock cores will be obtained if bedrock is encountered.
Borehole depths will be determined on a site specific basis, but will probablpe not exceed 100 feet. Standpipes will be installed in each boring.
4
4.0 STABILIZATION IN PLACE SITES 4.1 FIELD STUDIES The nature and material properties of the tailings piles must be determined in order to decide if stabilization in place can be accomplished without reconpacting the pile.
In addition, the behavior and stratigraphy of the foundation soils must be determined in order to assess the stability of the pile. A series of piezocone penetration tests similar to the static cone penetration test described in the ASTM D3441 will be performed at a minimum density of one (1) per acre to cover the Each test will penetrate the entire depth of the pile and tailings pile.
extend into the foundation soils until stiff or dense soils are Output from thhse tests is a continuous profile of the encountered.
stratigraphy (as shown on Figure 1) and a digital tape of the data 1)
Interpretation of data from these probes is used to:
collected.
define the stratigrapy of the pile in detail, thus locating all significant layers, zones, and pockets of slimes within the embankment;
- 2) determine the rate of dissipation of induced pore pressures (Figure 2) fx
- the rate of pore water pressure dissipation is used to estimate,in-situ
-tes hydraulic conductivity and consolidation parameters of the materials;
- 3) obtain the penetration resistance of the tailings and hence their strength and bearing capacity, and 4) determine the ground water level, W
f The stratigraphyl e interpreted from the piezocone is considered, g
These and[Sygge the location of additional boreholes is specified.
5
4 and d4SM borings are performed in order to obtain undisturbed [ samples for laboratory testing and to verify the stratigraphy defined 6[yomthe piezocone data.
Sufficient borings are conducted to verify the information derived from the piezocone. An appropriate sample interval is ond{of selected to assure that an adequate number of Shelby tube [ split barrel e
l (ASTM 03550) and/or SPT (ASTM 01586) samples of each material type are u
obtained. The Shelby tube and split barrel samples provide cadf-tut-d samples for laboratory testing. The standard penetration tests provide a basis for correlating data with other published or unpublished data,and are "Ead "ith the pie cccae d:t:
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Ground water ia t
levels at the time of drilling are determined, but piezometers are not necessarily installed. These borings extend a minimum of 20 feet below the tailings-natural soil interf ace. At least one of the borings is taken up to 20 feet into bedrock or up to 250 feet below the interface if
- # undation stratigraphy and material properties require definition.
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On small piles where piezoconing may be uneconomical, borings Iv1i#(cd:,*
conducted on a similar grid as described above will nevertheless be Y
advanced.
In such instances, continuous sampling, using the previously mentioned sampling techniques, will be performed through the tailings.
Test pits are excavated on the pile to obtain representative sand, sand-slime and slime tailings samples for laboratory testing. This data is used to determine the eotechnical properties of fill soils.
6
Af ter the evaluation of the first two stages of drilling, additional field work, including borings may be required to further define and characterize specific soil layers, zones of weakness, etc.
4.2 LABORATORY TESTING When the first phase of on-site drilling is conplete, the field data and samples are examined by the site geotechnical engineer and a laboratory testing program is specified. Laboratory testing of undisturbed and SPT samples for correlating material properties is undertaken. A listing and partial description of laboratory tests which may be assigned is shown as Attachment A.
In addition, strength (triaxial I
compression) compressibility (one-dimensional consolidation),
/
permeability, capillary moisture, and other tests may be conducted on the undisturbed soil samples.
The results of this testing are correlated with the piezocone data.
7
5.0 RELOCATED SITES (INCLUDING STABILIZATION ON SITE) 5.1 FIELD STUDIES 5.1.1.
Disposal area
( BoMota In order to determine the foundation soil and/or bedrock characteristics at the disposal sites, bcringi oie ieyuirett.
The density of borings is approximately one (1) boring for every three m,%m 4 p exb ac res. A sufficient area is covered to allow repositioning of the
'A pile within the general area of interest. Shelby tube (2-1/2 inch diamete split barrel and standard penetration test (SPT) samples
/
are collected to classify the soils, correlate data, and test in h
the laboratory. Ground water levels at the time of drilling are determined but generally piezometers are not installed. Field packer tests may be conducted, where applicable, in order to determine in-si tu hydraulic conductivity. These borings extend at least 20 feet below grade, with at least two borings extending up to 50 feet below grade or a minimum of 20 feet into bedrock.
One of the borings may extend as deep as 250 feet if the soil at the site i.s deep.
8
While the approximate number of borings has been indicated the location and depth of these borings depends upon the site conditions.
A grid pattern may be desirable at one location, but inappropriate at another.
The layout and position of holes should be defined for each site on the basis of site specific condition 9
6.0 BORROW AREA SITES 6.1 GENERAL Borrow areas are identified by performing a preliminary borrow asses sment. This study is performed by a TAC geologist or geotechnical engineer and consists of a review of pertinent data and a site visit.
Local materials contractors are contacted in order to obtain information on the availability of local borrow sources. Other sources of useful I
information include the Soil Conservation Service, Forest Service and state and local road departments, etc.
Ii i
6.2 PRELIMINARY STUDY 6.2.1 Radon cover Field program Af ter the preliminary borrow assessment, a if mited number of areas are investigated by excavating eight to 12 test pits at each area. The test pits are spaced so as to define the limits of suitable borrow material.
Both large and small bulk samples are obtained in order to perform classification and material properties tests. A field log of each test pit is compiled.
Water levels are recorded if water is encountered.
10
4 Mapping of the limits of suitable borrow areas is performed during the field studies.
Laboratory testing From visual examination of the soil samples and a review of test pit logs, the most suitable borrow area is selected and samples from this area are tested in a laboratory. More than one area may be tested if the most suitable source cannot be identified prior to testing.
Selected samples obtained from the field program are tested for their physical and mechanical properties, strength, conpressibility, hydraulic conductivity, capillarity, radon dif fusion, and erodability. Depending on the nature of the borrow source individual or mixed samples are tested.
In addition, soll amendments may be added to certain soils in order to alter their behavior.
6.2.2 Rock armoring Field program Following the preliminary borrow assessment one or more areas are investigated in order to define the limits and quality of Rock Armor borrow material.
For gravel sites, six to eight test pits are at each area. Both large and small bulk sagles y _.._, -y 11
i obtained in order to perform classification and material properties tests. A field log of each test pit is compiled. For bedrock sites, samples are obtained from rock outcrop areas.
Blasting to obtain samples may be required.
t.aboratory testing From visual examination of the gravel or rock from the field program and a review of the test pit logs, the most suitable borrow area is selected.for further testing.
If this cannot be done, several areas may ba tested.
Samples from the test pits are tested for minimal durability and soundness testing as outlined in the section on erosion barrier design criteria.
6.3 FINAL STUDY Field program After evaluating the field and laboratory test results from the preliminary study, a final field investigation is performed to verify the quantity and quality of available borrow material. The nature of this program depends upon the borrow site characteristics. This may involve drilling of borings as close as 100 foot on center, until sufficient 12
quantity is verified. Again, if encountered, water levels should be recorded. Samples or cores are obtained at approximately five foot on center.
Laboratory testing program A laboratory testing program consisting of gradation, Atterberg limits, and moisture and density determinations are performed in order to verify the correlation of the desirable material types in soils,Nr j
bedrock borrow sites, petrographic analysis of the rock core may be conducted as a verification of material types.
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Ff JACC8S ENGINEERING GROUP I( d ADV CONTRACT AS3-34-67C3-5-S'-0525 ExH!5fT A REVISION C
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Ot.TED 5/28/55 500DE OF WORK Basic Orderino Acreement for Geotechnical Laboratory Testing Inc. (Jacobs) requires the Subcontractor to Jacobs Engineering Groupprovide the services and supplies required fo soils in support of Jacobs' prime contract to the U.S.
of Energy under the Uranism Mill Tailings Remedial Action testing of Department (UMTRA) Project.
this progra will provide a cetailed evaluation of 20 to 30 potential borrow sites, about 10 uranium mill It is intenced tnat tne UUU Proje:t and as many as the soils at tailings sites to be reclairred under5 selected disposal si'.es sncaid pla:e prove impractical.
The following outlines the proposed scope of servic Sa ple collection ano celi,ery ill ce cone by otners.
m ater i al s.
Soil Samole Containers and Lateling 1.
in large an d s?.a ll pi astic bags, Snelby sa ples contained sa?ples will be pro-Soil 2 to 3 inch dia*eter tuce (ring)
Tne sa oles will tabes, and Obs' Technical Rep-esentative (TR).adecsate identification as vided by Ja:
be independently laceled by tne TR f or m
deptn, etc.
to site, location, sample ns ber, 2.
Laboratory Testing All Laboratory testing of retained soil samples will b i
of tne appropriate ASTM Standard or otne-specified standard.
Tests whien are anticipated to be required, but for whicn no stan-to present, in writ-dard esists, will require tne SubcontractorTnese methods will then ce ing, his test procedures to the TR. approved with modification to the satis-and the Subcontractor prior to perfoming any approved, disapproved or f action of the TRTests which may be ne:essary on eacn site include, bat testing.
are not limited to, tne following:
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n JACOBS ENGINEERING GROUP INC. **
ADVANCED SYSTEMS DIVISION, ALBUQUERGUE OPER ATIONS is
{( 4 Steve analysis with0J hytromiter (a5TM Cl36)
Sieve analysis witn nydrometer (ASTM 0422)
Atterberg limits (ASTM 0431S)
Moisture content (ASTM 02216)
Moisture density (ASTM 0698)
Moisture density (ASTM 01557)
Capillary moisture relationships (ASTv 03152 and ASTM 02325)
Specific gravity (ASTM 0554) 1110-2-1906)
Triaxial pe-meability (EM Constant head permeability ( Anty Corp of Enginee s EM 1110 1906)
Falling head permeability ( Army Corp of Engineers EM 1110 1906)
Tnree point sets Triaxial (R) ( Arry Corp of Engineers EM 1110-2-1906)
Tnree point sets Triaxial (Q) ( Arry Cers o' Enginee-s EM 1110-2-1906)
Three point direct snear test (CD) (ASTM 03030)
Tnree point direct snear test (CU)
Three point direct shear test (UU)
Ory density Slake duracility(International society for rock mecnanics, suggested matnod for cetermination of tne slake-durnoility index)
Three point sets California Bearing Ratio ( ASTM 01883)
One-dimensional consolidation (a5TM 02435)
Increments of seconcary consolidation (pe-macnine day)
Crumb tests (85TM Proceedings STP623)
Pinnole ( ASTM Proceedings STD623)
Double hydrometer (ASTM 0422)
Agg egate specific gravity and absorption (a5TM-Cl27)
Aggregate soundness (ASTM CSS)
Los Angeles abrasion ( ASTM C131 and C535)
Remol:ing of samp'es per test sample Rock crushing in preparation of samples per bulk sample tests that may be requested from time to time include:
Other Unconfined compression (ASTM 02166)
Relative density ( ASTM 04253 & 04254)
Snrinkage limit Percent passing No. 200 sieve Expansion, shrinkage and uplif t ( ASTM 03877)
Falling head permeacility conducted in association with consolidation tests (per load increment)
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6 F lF JACOPA ENGINEERING GROUP INC. **'
i(, ADVANCED SYSTEMS DIVISION, Al.BUGUERQUE OPER ATIONS 3.
Testinc Procedures a.
General All testing shall be perfomed in conformance witn the latest edition of the appropriate ASTM Str. cards or otner standara as
~
indicated by the type of test performed.
b.
Compacting Samples of Conesive Soil Samples of compa:ted soil shall be prepared in a split mold having inside dimensions equal to tne dimensions of the de-sired sample.
Tne method of Compacting inis soil into tne mold should duplicate as closely as possible the field com.pa:-
tion method.
Tne soil should be compatted into the mold in 6 equal layers using a pressing or kneading a:ti:n of a tamper having a contatt area with the soil of less than one-sixth the area of tne mold.
Tne surf ace of the layer shoald be tno -
oughly scarified before pla:ing the next layer. Uncer no cir-cumstan:es snall st an dard impa:t types of compaction be acceptable.
The sample shall be p-epa ed a::ording to the ASTM D-693 test procedure using an appropriate amount of water to produ:e tne desired water content.
Tne desired density snall be preda:ed by eithe-kneading or tamping each layer until this accumalated weignt of tne soil placed in tne mold is compa:ted to a known v:lume or by adjust-ing the number of tamps per layer and the force per tamp. For tne latter method of con t r ol, special constant force ta pers are necessary.
After each sample has been com;1:ted to fin-isned dimensions and removed f rom the meld, the appropriate lacoratory test may be performed.
Incat parameters such as moisture content at compaction, etc., will be provided Dy the TR.
Preparation of compa:ted granular soils should be performed as outlined in the U.S. Army Corp of Engineers' " Laboratory soil Testing," publication EM1110-2-1906.
c.
Consolidation Testing Consolidation tests must include time-rate of settlement plots of all load increments.
Tnese plots will be eitner log-time or square root of time plots, whichever best defines tne en:
of primary consolidation.
Falling head permeability tests may be required on certain consolidation tests.
N JACOP,S ENGINEERING GROUP INC,"'"
~
. (y F3w ADVANCED SYSTEMS DIVISION, ALBUQUERQUE OPER ATIONS i
d.
Falling Head pemeability Tests Testing procedures for f alling head perme a::i li ty tests sna'l be conducted accceding to EM ll10-2-19i6.
Input pa-a eters such as confining pressures will be provioed by tne T:1.
c.
least 95% saturation of tne samples is expected.
In acdition, f alling head tests, conda:tec during consolidation testing raj be required.
e.
Constant Head Permeacility Tests Testing procedures for constant Head Permeability Tests shall be performed according to EM 1110-2 1906.
Input para ete-s such as confining pressa es will be provided by Ja::cs Engineering Group Inc.
A: least 95% saturation of tne samoles is expected.
Pressure can be ao: lied to achieve sataeatice, but snall not exceed an e;Livalent position naad of 15 feet of
- water, f.
Triaxial Testing Triaxial testing of select undisturbed or compa:ted sam:les t
may include cermeability tests, unconsolidated undrained tests (0), consolidated undrained tests with pare pressure mea-surements (R).
All testing shall be conducted according to procedures outlined in EM 1110-2-1963.
's "S"
paraneter of 0.97 or higher is expected on all test samples prior to shearing, unless otnerwise indicated.
Input parameters such as confining pressures, etc., will be provided by the TR.
Photographs of tne sa ple shall be 19tladed in the test data, showing the condition of each sample at failure.
These shoul::
show an external vie *(s) and a cross se: tion view of tne sample.
g.
Capillary Moisture Relationships Capillary Moisture relationships shall be determined for a specific soil sample using a combination of ASTM D3152 and ASTM D2325 test methods to produce a series of moisture con-tents at tension values ranging from 0.1 to 15 bars.
The in-crements used shculd be 0.1, 0.3, 0.5, 0. 7, 1.0, 2.0, 4.0, 7.0, 10.0 and 15.0 bars.
4.
Project Schedule A site specific workplan (Delivery Order) will be sent to the Subcontractor along with the samples to be tested.
All analyses for each phase must be completed within four weeks af ter receipt of the samples unless otnerwise specified in the Delivery Oraer as issued.
For selected specific gravity, moisture density grada-tion and Atterberg Limits tests a two week completion will be required.
~
ri% JACOBS ENC,1NEERING GROUP INC. *
,,(p 0k ADVANCED SYSTEMS DIVISION, ALBUGUEROUE OPERATIONS 1
5.
Quality Assurance All laboratory testing shall ce perfomed by exoerienced and gaa'.
ified personnel in conf omance witn the apolicable ASTM test pro e-dures.
Any deviation froin these procedares or any analytical pro-ceda-es that are not available from ASTM snall be su bmi t ted in writing to the Jacobs Contract Representative (CR), who, after consulting Jacobs' Ouality Assurance M an age-will provide ao-proval of any such procedure, prior to perfoming the test.
Tnese deviations snall be carefully docu: ented and included on tne typed laboratory repc-t, Tne lacoratory which is to perforn-tne testing, including equipment, snall be available to t'ie 0AM's rep.
resentative prior to and during tne testing for inspe: tion.
The laboratory must have a Jacobs' approved Qua'ity Assu-ance (QA) Prog-a. in affect to assare tnat tne data t ans,itted is correct and tnat the lab tests were ran a: ording to tne required standard.
The Subcontractor's OA pr:g ar sna11 provide a des-ignated person as the primary contact person should any ques-tions arise as to the reliability of trans.mitted data.
6.
Cortract Performance All testing is subje:t to review and acceptance by Jacobs.
Acceptance or non-a:ceotance of a deliverable, will be made by tne TR within 14 days af ter receipt of test cata.
Tests improperly or inadequately performed will be retested at no cost to Jacobs.
All testing must be pe-formed by the Subcontractor.
No tests are to be furtnee sub:ontracted without prior apo oval by tne Jacobs CR.
If different tests are to be run at various laborato-ry's within tne same company, the tests which will be run at ea:n lac must be specifiec on Attachments to Exhibit C, and the rea-son given for more than one lac. Snipment of samples will only be paid by Jacobs to tne Subcontractor's laboratory nearest Albuquerque, New Mexico.
Any discrepancies in data must be identified and explaired on the
" Comments" section of the foms attached under Exhibit C; as to tne unusual nature or reason for apparent invalio test results.
7.
Deliverable Quality Assurance Results of all analyses shall be submitted on the specified report-ing forms (Exhibit C) and accompanied by legible copies of all as-Sociated laboratory work sheets.
Reporting forms shall be typewritten with all lines on the form being completed.
The let-ter designation "N/A' for not applicable or "N/K" for not known
6 h JACOBS ENGINEERING GROUP INC. **
='
ADVANCED SYSTEMS DIVISION, ALBUQUERQUE OPER ATIONS will be used in all blank spaces.
If some steps or procedures were not perfomed as specified by delivery order requirements, the reasons must be stated on the appropriate reporting fom or submitted as an attachment thereto.
All laboratory worksheets shall provide objective evidence that the data has been checked by qualified personnel other than those perfoming the tests.
8.
Sample Storace and Shipment Any remaining portions of samples shall be retained until dire:-
tion for disposal is received from Jacobs.
Bor ing and snipping will be the responsioility of tne Sub: ant-actor.
Snipping Charges when authorized by Jacobs, will De billable to Ja:oos.
Snipping cnarges will be paid at cost only.
Once testing of samples are co pleted they shall be re-sealed and stored for up to a period of six months, at an::n time tne TR snall be notified before tne samples are disposeo of.
9.
Health and Safety Recuirements Some of tne samples received will be uraniaa mill tailings. These samples shall be handled in accorcance witn OSH", 00T and any otn-er applicable safety standa-ds, such tnat conta.iqation of eaalp-ment and personnel is minimized.
Uraniun mill tailings are a lea- !evel na:n-doas aaste.
PRELIMINARY DRAFT GROUND SETTLEMENT
1.0 INTRODUCTION
Ground settlement at UMTRA sites is assessed in order to evaluate the long term stability of the tailings piles.
Settlement, especially differential settlement, can lead to flow concentrations.
If these flow concentrations exceed those calculated during design, erosion of the pile cover could occur.
In addition, severe differential settlement could lead to cracking of the radon cover.
Settlement can occur within the reclaimed tailings embankment and in the foundation soils upon which the em..inkment is constructed.
The absolute and A
differential settlement depend on:
12tr the distribution of different types of materials; the compressibility of each soil type; and the stresses on specific
.E Q soil layers.
35 t*
{a'linsi
$'k A tailings pile is a heterogeneous deposit of[ sands (<30 percent passing "g
t***"
l9" M **7'_l
/ kutad folhe95 y
the #200 sieve),4 slimes (EJpercent ret: = 4the #200 sieve) and[ sand-slimes m
1 1
mixtures]. Usually the sand tailings are found on a " beach" close to the
+
4perimeterofthepiles.
Slimes which are settle in the decant pond, are distant "i
from the discharge points. The sand slimes mixture is generally located between
)
u d
the te. The position of the pond and slimes may vary widely as a result of spigotting from different discharge points. Layers of sand tailings may be y
deposited over layers of slimes and vice versa.
Slime lenses may be close to o
E 45.
the beach due to local pools. Tailings will consist of interlayered and interfilled sand and slime stringer lenses and layers ranging from several microns thick up to many feet. Material size varies both vertically and horizontally due to the shif ting and braiding of the discharge flow over previously[depositedtailings.
For settlement analyses, only the gross stratigraphy of a tailings pile can be considered. 1.arge areas of sand, slime,and sand-slime mixtures (including s
interlayered sands and slimes as sed-slimes mixtures) are identified for use in analyzing settlement of the tailings.
If the tailings pile is relocated, the absolute and differential settlement of the embankment are reduced since the tailings are compacted. Differential settlement is difficult to predict, however, because a uniform distribution of
~
material types may not be achieved.
2
2.0 DATA COLLECTION Data collection begins with characterization of the tailings pile and the foundation soils at the preferred alternative disposal area. Emphasis is placed on defining areas of sands, slimes, and sand-slime mixtures within the tailings.
Zones of soft soil are delineated in the foundation soils. The ground water table is defined, as are zones of partially saturated soils above the water table.
M fs}v m.e d griws tes45 Materials compressibility is def t..ed ) SPT[h =u.its, the piezocone peu%N 4ed i,e,ia, under (including pore pressure decay), and tests on samples from Shelby tubes or ring lined split barrel samplers. Consolidation tests may be performed on saturated soil, or at the natural moisture content of the soil depending on the location of the sample in relation to the water table and the degree of saturation of the strata from which the sample is obtained.
3
4 3.0 ANALYSES The method of analysis depends on the material type, the dat'a collected for that material, and the condition of the material in-place. Calculations based on elastic analyses are used for nonplastic soils. Consolidation theory as described by Lambe and Whitman (1969) is used for clays. Other methods of analysis such as those based on finite strain may be used if appropriate.
The instantaneous settlement of the embankment and the foundation soils is calculated. Short-term (primary) settlement of the embankment and the foundation soils is calculated. Long-term settlement based on secondary consolidation is evaluated and if substantial, is calculated for the embankment and the foundation soils.
Total combined settlement (excluding instantaneous settlement) is plotted as a surf ace contour map in order to evaluate differential settlement, cover cracking and flow concentrations. Cover cracking is evaluated using the Shen approach described by Lee and Swen (1969).
Some theories that may be used to calculate settlements:
o Elastic theories as presented in Lambe and Whitman (1969), and NAVFAC pp de'#
DM-7 (1983).
g o Conventional consolidation theory as presented in -tambe and Whitman pg W (1969), and Duncan and Buchignani,1976.
4
Multi layered analyses using conventional consolidation theory as Wo bU presented by f4 G79 -
fe%Rwm y[
o Finite strain settlement techniques as developed by E'-^rt :aa (1984 ).
o Cone penetration techniques as presented by Robertson and Companella (1984), 6nd Schmertmann (1976i.
[o Analysis of secondary consolidation as presented by Holty and Kovacs (1981).
psa, aii,
,g,t. W p r h (*
- fM S *'p
@ph fMs pa* f 5
4.0 FINAL. CONDITION The size of the tailings embankment the complexity of the subsurface stratigraphy bolt within tailings piles and foundation soils, and the limited data frosi which to derive design parameters, make the prediction of total and differential settlements inexact.
In order to reduce the uncertainty and raise the reliability of long-term stabilization, several construction and design features may required:
o Monitor the embankment settlement to note when settlement is complete.
Place the radon cover material only when settlement is complete. This will lessen the chances of cover cracking due to differential settlement.
Monitor for cortpletion of settlement af ter placing but before final o
grading of the radon cover. This lessens the chance of unanticipated flow concentrations due to storm water runoff.
o Place cover material at two to three percent above the optimum-moisture content. This makes the material more pliable and less likely to crack due to settlement.
load 8^1 O
h heit; C ifh, g
f u n k,,p.
f hent 4 constdei Atk ms+ h sur -.
trd~ path romank Adh J,
gue,a s n s
al inplaw Ak61/9d.m SA, po,blul3 6
~ - -
REFERENCES t.ambe and Whi tman,1969. Soil Mechanics, Massachusetts Institute of Technology, Boston, Massacnusetts.
t.ee, K.t..,
and C.K. Shen.
" Horizontal Movements Related to Subsidence,"
Journal of the Soil Mechanics and Foundation Division, ASCE, Vol. 95, SM.1, pp. 138-166.
1 ha %
7 I
1 FINAL DRAFT LIQUEFACTION POTENTIAL
1.0 INTRODUCTION
In order to evaluate the long term stability of tailings piles at UMTRA sites, the liquefaction potential of the pile under Design Earthquake conditions will be assessed.
(See Chapter _ for definition of the Design Earthquake).
Liquefaction and/or cyclic mobility can occur only in saturated, cohesionless soils (sands and silts) due to cyclic loading, which is usually caused by earthquake induced ground motions. Liquefaction occurs when the effective stress in the soil is reduced to zero by the earthquake induced buildup of pore water pressure. When this occurs, the shearing resistance of the soil reduces and the soll becomes essentially a viscous fluid. Cyclic mobility, on the other hand, occurs in denser soils. Af ter the earthquake the pore pressures reduce, and the shear strength resistance increases.
1
r The most important factors used to assess the liquefaction or cyclic mobility potential at a site are:
- 1) the ratio of earthquake induced shear stresses in the soil to the vertical effective stress; and 2) the relative density (D ) of the soil or tailings mass.
r There is a practical maximum earthquake induced ground acceleration, and thus a maximum shear stress that can be produced in a soil or tailings mass by the large earthquakes. This means that as tne soil or tallings mass in question gets deeper, the ratio of the maximum possible shear stress to effective stress reduces. This generally precludes liquefaction and/or cyclic mobility at depths greater than approximately 50 feet below the ground or soil mass upper surf ace.
Most researchers agree that there is a relative density above which liquef action cannot occur. Liquefaction can occur in soils with a relative density (D ) less than 40 percent (Seed,1976). Generally, above a D of 70 r
r percent, neither liquefaction nor cyclic mobility can occur (Casagrande,1975).
o 2
o 2.1 GENERAL Because most UMTRA sites involve unsaturated tailings piles, the potential for liquef action f ailure are minimal.
Each site will, however, be evaluated on its own merits. The design methods outlined below will be used for this evaluation.
2.2 ANALYSIS The method of analysis selected to assess liquefaction potential is that developed by Seed and Idriss (1982).
This analyses, assumes that no liquefaction will occur above the water table.
It should be noted that this assumption may not be valid if there is an extensive saturated zone above the perched water table. These cases will be analyzed for liquefaction.
The method further assumes that only sands (SP,5W), silty sands (SM), and low plasticity silts (ML) are capable of liquefying.
The Seed and Idriss simplified method is based on empirical correlation of documented cases of liquefaction, measured earthquake Richter magnitudes (M), maximum horizontal ground acceleration at the site, and the standard penetration test (SPT) blow count (N) (determined according to ASTM D1586) or the cone penetration resistance (Robertson and Campanella,1984) of the soil prior to liquef action.
3
I In order to determine the design horizontal ground acceleration at the site, it -is necessary first to determine the acceleration in the bedrock below the site. This is achieved by establishing the design
- earthquake and the distance to the causative fault.
Using an attenuation curve developed in the seismic position paper (Chapter _) the bedrock acceleration is established.
Since this motion will be either attenuated or amplified by the foundation soils at the site, the appropriate curve, as presented in the paper by Seed and Idriss, is used to estimate the design horizontal ground acceleration at the surface of the site. This acceleration is used to determine the shear stresses developed by the earthquake in the various soil layers of the site.
The shear stresses developed by the earthquake are compared to the shear stress required to cause liquef action in a particular layer.
The shear stress required to cause liquefaction is found from a f amily of curves (Seed and Idriss,1982), relating the given magnitude and the SPT blow count or cone penetration resistance appropriate to the layer. These curves enable full account to be taken of the soil or tallings grain size distribution.
Seed and Idriss state.that a f actor of safety against liquefaction in a given soil or tailings layer may be calculated by dividing the shear stress required to cause liquefaction in the layer by the shear stress generated in that layer by the design earthquake. They state that a factor of safety between 1.25 and and 1.5 should be taken as the minimum.
4
In addition to analyzing potential liquefaction the consequences of failure are evaluated. Typically, the minimum f actor of safety considered acceptable for UMTRA sites is 1.5.
Should the consequences of f ailure be found to be minor (i.e. localized swamping and cracking of the cover),
having a liquefaction potential may be considered acceptable for design.
If site specific conditions are such that the consequences of failure are significant and the simplified analyses produce safety f actors below 1.5, then more detailed site specific analyses using measured dynamic soil parameters, etc., will be undertaken.
5
e 1
Casagrande, A.,1975, " Liquefaction and Cyclic Deformation of Sands - A Critical Review", Harvard Soil Mechanics Series No. 88, paper presented at the Fif th Pan American Conference on Soil Mechanics and Foundation Engineering, Buenos Aires, Argentina.
Robertson, P.K. and R.G. Campanella,1984.
Guideline for Use and Interpretation of the Electronic Cove Penetration Test, The University of British Columbia, Vancouver, B.C., Canada.
Seed, H.B.,1975, "Some Aspects of Sand Liquefaction Under Earthquake loading",
in Proceedings of the International Conference on Behavior of Off-Shore Structures, August 25, 1976, Trondheim, Norway.
Seed, H.B., and I.M. Idriss,1982, Ground Motions and Soil liquefaction During Earthquakes, Earthquake Engineering Institute, Berkeley, California.
6