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I ? r YEH AND ASSOCIATES, INC. I Project: Bowie Landslide Study I <br />GEOTECHNICAL ENGINEERING CONSULTANTS Project Number: 25-196 <br />Legend for Symbols Used on Borehole Logs <br />N-value (SPT Blows) <br />N The number of blows required to penetrate the last 12 inches. Thus, the N-value represents <br />the number of blows per foot <br />Practical Drill Rig Drive Refusal <br />R Represents 50 blows from a 140 pound hammer falling 30 inches could not drive the <br />sampler 12 inches. The sampler either "bounces" or just "chips away" at that particular <br />drive elevation. <br />Sample Types <br />Split Spoon Sampler. The symbol 15/12 indicates that 15 blows from a 140 pound hammer <br />falling 30 Inches was used to drive 1.375-inch I.D. sampler 12 inches. <br />? ModHied Carifomla Sampler. The symbol 16112 indicates that 16 blows from a 140 pound <br />hammer failing 30 inches was used to drive 24nch I.D. sampler 12 inches. <br />Soil Lithology <br />® CLAY, silty to sandy, slightly moist to moist, medium stiff to very stiff, brown, tan (CL, CH). <br />SAND, clayey, slightly moist to moist, medium dense to very dense, brown (SC). <br />CLAY, gravelly, occasional cobbles and boulders, dry to damp, very stiff to hand, brown <br />(Landslide Debris) <br />Bedrock Lithology <br />IT] SANDSTONE, slightly moist, hard to very hand, brown, tan, red-brown. <br />® INTERBEDDED CLAYSTONE (SHALE) / SANDSTONE, slightly moist, hard to very hard, <br />brown, gray, olive. <br />Lab Test Abbreviations <br />MC-Moisture Content <br />DD-Dry Density <br />#200-Percent Passing #200 Sieve <br />LL-Liquid Limit <br />PL-Plastic Limit <br />PI-Plastic Index <br />S-Sulfate Content <br />S/C-Swell/Consolidation <br />UCCS-Unconfined Compressive Strength <br />* Indicates that gradation analysis was performed, Atterberg limits were not performed, but the <br />USCS classification was applied assuming non plastic characteristics