ML20206L058
| ML20206L058 | |
| Person / Time | |
|---|---|
| Site: | PROJ0734 |
| Issue date: | 01/18/2012 |
| From: | Nothdurft D Office of Nuclear Material Safety and Safeguards |
| To: | |
| Desotell L | |
| Shared Package | |
| ML20206K862 | List: |
| References | |
| K-CLC-Z-00020, Rev 0 | |
| Download: ML20206L058 (28) | |
Text
K-CLC-Z-00020, Rev. 0 Sheet 2
- 1. INTRODUCTION This calculation identifies engineering stratigraphic layers for SPT and CPTU soundings performed for the Saltstone Vault No. 1. Engineering stratigraphic layers and nomenclature were based on previous subsurface investigations performed within Z Area generally, and the Vault No. 1 area particularly, by Mueser Rutledge Consulting Engineers (MRCE) (Ref 1) and SRS (Ref 2). Figure 1 depicts the location of Vault 1 within Z Area.
- 2. INPUT DATA Recent subsurface data acquired for the Saltstone Vault No. 1 investigation included four (4) seismic piezocone penetration test (SCPTU) soundings and six (6) piezocone penetration test soundings (CPTU) (Ref. 4). In addition seven (7) borings were drilled in two previous explorations in 1986 (Ref 1) and 1992 (Ref 2). These locations are depicted in Figure 1.
- 3. METHOD FOR DETERMINATION OF ENGINEERING LAYERS Engineering layers developed for the Saltstone Vault No. 1 area followed a scheme previously used by other investigations in Z Area. Using this same layering scheme provided a means to compare subsurface conditions between investigation sites. An S or C designation was used to divide layers into predominantly sand and clay units, respectively. The upper layer S1/2 consists of the Upland Formation, Tobacco Road Formation, and the upper portion of the Dry Branch Formation; layer S1/2 extends from the surface to the C2 layer. The C2 layer corresponds to what has commonly been termed the "tan clay" layer which occurs within the Dry Branch Formation as a facies of the Irwinton Sand. The S3 layer is the lower portion of the Dry Branch Formation and occurs between the C2 layer and the S4 layer. The S4 layer corresponds to the Santee/Tinker units of the Lisbon Formation. The Congaree formation is denoted as M1 because it typically occurs as a predominately silty layer.
CPT and SCPT explorations and SPT boring data were used to determine the thickness and presence of the engineering layers. Patterns in tip stress, sleeve stress, ratio of tip stress to sleeve stress, and pore pressure responses were used in differentiating the soil layers. Soil properties exhibited in the CPT and SCPT soundings were compared to descriptions of soil samples collected from SPT borings advanced in 1986 and 1992, and information published from previous Saltstone vault studies (Ref 3) was used to correlate engineering soil layers at the site to regional geologic units and soil stratigraphy at the SRS.
Two engineering layers, C2 and S4, were identified as critical surfaces from a review of the existing data. These layers were developed from previous geotechnical studies performed in the area. The first layer, C2, was historically identified on boring logs from low N-value measurements and visually from field procedures on split-spoon contents. This layer is easily identifiable in CPT logs from a sudden drastic decrease in tip resistance accompanied by a sudden drastic increase in sleeve friction and pore pressure. Field and laboratory data suggest this layer contains considerable fines. The second layer, S4, has been identified as the Santee/Tinker surface.
K-CLC-Z-00020, Rev. 0 Sheet 3 Geologic stratigraphy (specifically the top of the Santee/Tinker interval) was determined from the ten CPT pushes advanced as part of this investigation, and coordinated with that reported in the two previous SPT investigations. The top of the Santee/Tinker Formation (designated S4) was determined solely for the purpose of the liquefaction potential analysis. The Upland, Tobacco Road and Dry Branch (except for C2) formations overlying the Santee/Tinker Formation were not differentiated as part of this study. Copies of the CPT logs are provided in the Attachment.
The top of the Santee/Tinker interval was visually determined in previous borings from soil samples as a marked change in the gradation, color, mineralogy, and reaction to dilute hydrochloric acid (HCl) solution. The gradational change from Dry Branch to Santee/Tinker was noted as becoming more fine grained while the color became more greenish and the mineralogy transitioned from an abundance of manganese oxide to the presence of calcite (positive HCl reaction) and glauconite.
Table 1 summarizes the contacts between stratigraphic layers based on the SPT boring logs conducted in 1986 and 1992.
Table 1 - Engineering Stratigraphy Based on Previous (1986 & 1992) SPT Borings Ground Total Congaree Boring ID C2 S3 S4 SRS_N SRS_E Elevation Depth (M1)
Z-215 294.7 161.5 - 217 172 141 75,987 66,275 Z-216 294.5 146.5 217 207 167 142 75,797 66,337 Z-217 295.5 167.5 223 217 182 137 75,608 66,400 ZB-1 283 142 214 205 176 141 76,105 66,342 ZB-3 285 147 220 197 181 138 75,911 66,406 ZB-5 284.5 142 218 195 178 143 75,717 66,469 ZB-7 285 142 216 210 180 145 75,523 66,533 Tops of Stratigraphic Layers in feet msl.
The Congaree Formation (M1), which consists of dense, variably clayey coarse sands, was identified in the borings and on a few CPT signatures. This formation appears to be relatively flat across the site and exists at an elevation of approximately 142 ft, msl. CPTs Z-V1-C-01, Z-V1-C-03, and Z-V1-C-04 refused on (did not penetrate) the top of the Congaree Formation. The remaining CPTs refused within the Dry Branch Formation.
- 4. SOFT ZONES Since the early 1950s, numerous subsurface and geotechnical studies at SRS have determined that the soils within 200 feet of the surface consist mainly of sands, clayey sands, and silty sands. Several SRS geotechnical explorations have encountered weak zones within stronger materials in the lower Dry Branch and the upper Santee/Tinker interval. Low tip resistance and SPT values and drilling rod drops are common indicators of these weak zones, which are referred to as "soft zones". With regard to CPT penetration, soft zones are defined as soils with a continuous corrected tip stress of 15 tons per square foot (tsf) or less over elevation intervals of at least 1.5 feet within the lower Dry Branch or the Santee/Tinker interval Formations (engineering layers S3 and S4 respectively).
K-CLC-Z-00020, Rev. 0 Sheet 4
- 5. RESULTS AND CONCLUSIONS Engineering stratigraphy for Saltstone Vault No. 1 SPT borings and CPT soundings is summarized in Tables 1 and 2 respectively. The elevations shown for the top of S3 are also the elevations for the bottom of C2.
Table 2 - Engineering Stratigraphy Based on CPTs Ground Total CPT ID C2 S3 S4 M1 SRS_N SRS_E Elevation Depth Z-V1-C01 284.1 152.1 210 201 194 142 76084.0 66243.0 Z-V1-C02 285.7 126.7 217 205 199 NDE 76005.0 66333.1 Z-V1-C03 285.7 156.7 214 NP 195 145 75895.5 66369.2 Z-V1-C04 285.7 156.5 220 208 195 138 75750.1 66417.3 Z-V1-C05 285.4 110.2 222 212 198 NDE 75620.0 66459.9 Z-V1-C06 283.7 123.3 216 202 198 NDE 75488.0 66441.9 Z-V1-C07 283.5 109.9 221 210 196 NDE 75574.8 66346.5 Z-V1-C08 283.5 119.2 219 206 194 NDE 75688.8 66308.7 Z-V1-C09 283.4 134.7 215 - 195 NDE 75832.6 66261.2 Z-V1-C10 283.5 122.9 216 201 195 NDE 75960.9 66218.0 Tops of Stratigraphic Layers in feet msl.
NDE - Not Deep Enough NP - Not Present
- 6. REFERENCES
- 1. Mueser Rutledge Consulting Engineers (MRCE), Report: Saltstone Disposal Investigation, 1986, File Z-SDF-2
- 2. Bechtel Savannah River, Inc. (BSRI), Report: Z-Area Vault No. 2 Geotechnical Investigations Report, C-ESR-Z-00001, BSRI, 1992, File Z-SDF-9
- 3. K-CLC-Z-00003, Subsurface Stratigraphy for the Saltstone Vault No. 4, Rev 0.
- 4. LanKelma, Inc.; SRNS Strategic Agreement SAQ003; Purchase Order AC76230N; Task Order 03; SOW 4T5310, July 27, 2010
- 7. LIST OF FIGURES Figure 1: Vault 1 Location Map with Geotechnical Investigation Locations Figure 2: Section 1-1 from 1986 Geotechnical Investigation (ref. 1)
Figure 3: Cross-section from Bechtel Vault 2 Geotechnical Rpt C-ESR-Z-00001 Z-SDF-9 (ref.2)
- 8. ATTACHMENTS Attachment 1: CPT Data Curves (engineering strata indicated)
K-CLC-Z-00020, Rev. 0 Sheet 5 Figure 1: Vault 1 Location Map with Geotechnical Investigation Locations
K-CLC-Z-00020, Rev. 0 Sheet 6 Figure 2: Section 1-1 from 1986 Geotechnical Investigation (ref. 1)
K-CLC-Z-00020, Rev. 0 Sheet 7 Figure 3: Cross-section from Bechtel Vault 2 Geotechnical Rpt C-ESR-Z-00001 Z-SDF-9 (ref.2)
K-CLC-Z-00020, Rev. 0 Sheet 8
Attachment:
CPT Data Curves with engineering strata indicated
S1 S2 C2 - Tan Clay
S3 S4 - Santee M1 - Congaree indicates 15 tsf
S1 S2 C2 - Tan Clay
S3 S4 - Santee indicates 15 tsf
S1 S2 C2 - Tan Clay
S4 - Santee 2-ft soft zone 0.7-ft soft zone 0.3-ft soft zone M1 - Congaree indicates 15 tsf
S1 S2 - TR/
Upper DB C2 - Tan Clay
S4 - Lower Dry Branch S4 - Santee 1.6-ft soft zone indicates 15 tsf M1 - Congaree
S1 S2 C2 - Tan Clay S3
S4 - Santee 1.6-ft soft zone indicates 15 tsf
S1 S2 C2 - Tan Clay
S3 S4 - Santee 3-ft thick soft zone indicates 15 tsf
S1 S2 C2 - Tan Clay S3
S4 - Santee indicates 15 tsf
S1 S2 C2 - Tan Clay
S3 S4 - Santee indicates 15 tsf
S1 S2 C2 - Tan Clay
S4 - Santee indicates 15 tsf
S1 S2 C2 - Tan Clay
S3 S4 - Santee indicates 15 tsf