Laserfiche WebLink
Geotechnical Data Report Bruca Park Dam <br /> Bowie Resources, Limitetl <br /> Apri12001 <br />5.7 Triaxial Shear <br />Triaxial shear tests with pore pressure measurements (ASTM D-4767) were performed on <br />samples of "new" embankment fill, "old" embankment fill, and foundation materials. Test <br />results were used to evaluate shear strength. The testing was performed on undisturbed <br />Shelby samples collected from the "old" and "new" embankment fills. Testing was <br />performed on one HQ core sample collected from the foundation materials below the main <br />dam. Plots of the effective stress paths (P-q plots) and undrained shear strength as a function <br />of consolidation stress aze presented on Figures C.1 through C.6 in Appendix C. <br />The sample from the "new" embankment fill has a measured effective cohesion of zero and <br />an effective friction angle of 39 degrees. The undrained shear strength vanes according to <br />the consolidation stress. For consolidation stresses up to 1,500 psf, the approximate <br />undrained sheaz strength is 1,100 psf as shown on the plot on figure C.2 in Appendix C. <br />The sample of "old" embankment fill has a measured effective cohesion of 380 pounds per <br />square foot (psf) and an effective friction angle of 35 degrees. The approximate undrained <br />sheaz strength is 1,900 psf for consolidation stresses up to 2,200 psf as shown on the plot on <br />figure C.4 in Appendix C. <br />The sample of foundation material has a measured effective cohesion of 390 psf and an <br />effective friction angle of 26 degrees. The approximate undrained sheaz strength is 2,000 psf <br />for consolidation stresses to 3,000 psf as shown on the plot on figure C.6 in Appendix C. <br />5.8 Consolidation <br />Consolidation tests (ASTM D-243) were performed to assist in evaluating the behavior of <br />embankment and foundation soils under additional loading and the degree of consolidation of <br />in-place soils. The testing was performed on dry core sampler collected from the "old" and <br />"new" embankment fills and on HQ core samples collected from the foundation materials <br />below the main dam. Consolidation test results provide data to determine preconsolidation <br />pressure, overconsolidation ratio, compression index, and recompression index. <br />The preconsolidation pressure (aP') indicates the maximum stress to which the soil has been <br />loaded during its lifetime. The overconsolidation ratio (OCR) is the ratio of the <br />preconsolidation pressure to the existing overburden pressure. The recompression index (CR) <br />is an indication of the behavior of the soil as it is being reloaded below the preconsolidation <br />pressure, 6~'. The compression index (C~) is an indication of the behavior of the soil as it is <br />being loaded above the preconsolidation pressure. <br />GEI Consultan[s, Inc. 1 t 9929201-~e-t5 Geo~ecM~C21 Daa Repm <br />