Total stress method1
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This document describes calculating the factor of safety for a two-layer sloped soil using the total stress method. The slope has Soil A and Soil B with different cohesion and friction angle properties. The method involves calculating the slope angles for each soil layer. The total resisting and driving forces are then used to calculate the factor of safety, which is found to be 1.59 and indicates the slope is stable.
Total stress method1
- 1. Haspina Sulaiman |CC502 (Slope Stability) 1 Total Stress Method Figure S5 shows a slope with two layer of soil. The bulk density of Soil A and B are 20.5kN/m2 . If Cu=24 kN/m2 , ?u = 0 for soil A and Cu=20 kN/m2 , ?u = 0 for soil B, find the factor of safety using Total Stress Method. ( 25 marks ) Solutions: Tan ?1 = 15 91.3 ?1 = tan-1 ? ? ? ? ? ? 15 91.3 = 14.60 ( 3 markah ) 15.5 3.91 15 ?1 O Tanah A Tanah B Luas Tanah A + Tanah B = 48 m2 15.5m 6m 5m 4m 2m2.5m W 450 450
- 2. Haspina Sulaiman |CC502 (Slope Stability) 2 kos ?2 = 5.15 11 ?2 = kos-1 ? ? ? ? ? ? 5.15 11 = 44.80 ( 3 markah ) kos ( ?2 + ?3 ) = 5.15 6 44.80 + ?3 = kos-1 ? ? ? ? ? ? 5.15 6 ?3 = 67.20 ¨C 44.80 = 22.40 ( 4 markah ) W = Luas x ? = 48 x 20.5 = 984 m2 ( 3 markah ) ?A = ?3 = 22.40 ( 1 markah ) ?B = ?2 + ?1 = 44.80 + 14.60 = 59.40 ( 2 markah ) Faktor keselamatan, F.K : F.K = Wd ¦ÈRC¦ÈRC B 2 BA 2 A ? ( 2 markah ) = )5.4(984 ) 180 4.59()5.15(20) 180 4.22()5.15(22 22 ? ? ? ? ? ? ??? ?? ( 5 markah) = 4428 47.498139.2066 ? = 1.59 > 1 (SELAMAT) ( 2 markah) ?2 11 15.5 ?3 6 15.5