Unformatted text preview: be based on an effective stress analysis using the drained strengths. o~ = LrH -u = (18.7 kN/m 3)(4.9 m) + (19.2 kN/m 3)(5.2 m) - (9.8 kN/m 3)(5.2 m) 140 kPa Long tenn F = !. = 69 kPa = 11 -Answer 1:" 60 kPa • .. s '" c' + 0' tancf>' " 18 kPa + (140 kPa) tan 20 0 69 k:Pa Comments Immediately after construction, the factor of safety at Point A is 1.7, which would usually be acceptable. However, once the negative excess pore water pressures have dissipated, F drops to only 1.1, which would generally not be acceptable. If the groundwater table rose, or if the actual c' and <p' values are slightly different than we think, failure could occur. The factors of safety in this example only represent the conditions at Point A, and are intended only to illustrate the effects of negative pore water pressure dissipation. Actual slope stability analyses require assessment of the factor of safety along the entire shear surface, as discussed in Chapter 14....
View Full Document
This note was uploaded on 09/23/2011 for the course CIVIL ENGI CE 3400 taught by Professor Rosenblad during the Spring '11 term at Missouri (Mizzou).
- Spring '11
- Geotechnical Engineering