Dingee Reservoir Final Seismic Report - East Bay Municipal Utility ...

3.3 Laboratory Testing
Soil and rock samples obtained from the subsurface investigation were carefully packaged and
sealed to prevent disturbance and to reduce moisture loss. The soil and rock samples were
carefully inspected and reviewed for verification of the field classification by an engineer from
the Materials Engineering Section before representative samples from the various strata were
selected for laboratory testing. Appropriate tests were selected to assist in subsequent evaluation
of material properties for use in the stability evaluation. The tests performed are listed in Table
2A and 2B along with their ASTM designations.
Table 2A: Laboratory Index Tests and Results Location
Test Description ASTM Designation Results Location
In-situ moisture-density ASTM D2216, D2937 Plate B-1 & B-2 {App. B}
Sieve analysis ASTM D422 Plate B-1 & B-2 {App. B}
Hydrometer analysis ASTM D422 Plate B-1 & B-2 {App. B}
Atterberg limits ASTM D4318 Plate 7 & Plate B-2 {App. B}
Index tests were performed on all samples that were tested for shear strength determination. The
results of these index tests are also summarized together with the strength test results. All testing
was performed at the District’s Materials Testing Laboratory. The laboratory tests were
performed in general accordance with the noted ASTM standards. Consolidation pressures for
the Isotropically Consolidated Undrained (ICU) tests were selected based on the estimated
overburden pressure at each sample depth. Abbreviated test results for each sample are also
included in the boring logs at the appropriate depth. Plates 8, 9, 10, and 11 provide a summary
of the in-situ moisture contents, total and dry unit weights, and estimated void ratios for the
samples from borings XV-1 to XV-15.
Table 2B: Laboratory Shear Strength Tests and Results Location
ASTM
Test Description
Results on
Designation
Isotropically consolidated undrained
(ICU) triaxial compression test with
pore pressure measurements
Unconsolidated consolidated (UU)
triaxial compression test
Direct Shear Test (DS)
ASTM D2166
ASTM D2166
ASTM D3080
Plates B-3
& Appendix B
Plates B-4
& Appendix B
Plate B-5
& Appendix B
The results from the 1971 investigation program are included in Plates 8 through 11. As shown
on these plates, the in-situ moisture contents, unit weights, and void ratios (1971 lab data vs.
2006 lab data) are comparable. Table B-2 in Appendix B, provides a summary of the Atterberg
Limits tests for fine-grained soils and fine-grained fraction of coarse-grained soils. The
interpretation of the laboratory data is presented in Sections 5 and 6 of this report.
Seismic Stability Evaluation Report
Dingee Reservoir Dam
9
August 2008