A footblock is inclined 1.5 on 1 horizontal with height D = 3 ft. Assume the soil has undrained shear strength Cu only (=0), and negligible self-weight.

Estimate the ultimate load Pult, assuming a long strip footing, by using:

(a) any upper bound estimate (circular arc or straight line failure)

(b) any lower bound solution. Note that it is possible to obtain an exact lower bound estimate by starting with 45 wedges of soil below ground surface to the right of the footblock and another one directly below the footblack and rotating the corresponding Mohr circles from region to the other.

(c) A practitioner has proposed an empirical allowable Pall for this footblock of 94 kips where his block is 4 ft long in the out-of plane direction. Assume Cu = 95.8 kPa (appropriate for a stiff clay) Comment on your values compared to his.

Note that the practitioner's Pall is an allowable load, not an ultimate load. 1 kip = 1000 lb force = 4.448 kN and 1 kip/ft2 = 47.88 kPa.