Laserfiche WebLink
• consisted of 7 to 23 feet of clays soils underlain by claystone (clay shale) bedrock. <br />Boring logs are included in Appendix A and laboratory test data are presented in <br />Appendix B. <br />The clay soils were medium stiff to stiff in borings and pRs TH-3/TP-3 which <br />were located near the flow line in the lower portion of the valley. A clay sample <br />tested from this area exhibited an unconfined compressive strength of 3,460 pounds <br />per square foot (psf). Consolidated-undrained triaxial testing with pore pressure <br />measurements indicated an effective stress friction angle of 25 degrees and a <br />cohesion of 380 psf. <br />In the remaining borings the clay soils were stiff to very stiff. The results of <br />10 unconfined compressive strength tests on the clays from this area showed <br />• strengths ranging from 3,640 to 17,880 psf; typical values were 5,000 to 8,000 psf. <br />The clay samples tested had liquid limits of 43 to 44 percent, plasticity indices of 26 <br />and 30 percent, and 82 to 85 percent passing the No. 200 sieve. <br />The bedrock consisted of claystone with occasional layers of siltstone or <br />clayey sandstone. The bedrock was hard to very hard, slightly moist and dark gray, <br />brown and rust. Penetration resistance values ranged from 50 blows for 9 inches <br />of penetration to 25 blows for zero inches of penetration. Unconfined compression <br />testing of one sample of the bedrock indicated a strength of 16,220 psf. Recovery <br />of short samples limited the strength testing performed. Visual examination, <br />~ experience from previous projects and the results of the penetration testing confirm <br />a comparatively high strength for the bedrock as indicated by the unconfined test. <br /> <br />• <br />6 <br /> <br />