A 3 × 4 pile group was constructed in layered saturated clay. The piles are 0.25 x 0.25 m in section, and are spaced at 0.75 m centre-to-centre. The ground consists of two layers. The characteristics of the clays are as follows: The upper soft clay layer: c = 50kPa, Yat=18kN/m³. The lower layer: c = 120kPa, Y = 20kN/m³. sal The ground water table is at ground surface. Determine the ultimate load bearing capacity of the pile group. 5 m Cu 50 kPa = Ysat 18 kN/m³ 15m Cu 120 kPa Ysat 20 kN/m³