A 2.0m-wide strip at a depth of 1 m in a stiff clay carries a wall load of 425 kN/m. The saturated unit weight of the caly is 20kN/m^3. TRiaixal tests give the following results: c'=10 kPa, phi'=28 degree, cu=105kPa, and phi_u = 0. EStimate the long-term safety factors.