Answer Happy

3. The plan view of a pile group is given in the figure (pile length = 16 m). (a) If the piles are embedded in sandy ground (’ = 30° and c’ = 0) with groundwater table at a depth of 3 m (for depth 3 m, = 17 kN/m3; for depth > 3 m, sat = 19 kN/m3), determine: (i) the ultimate point load Qp (10%) and (ii) the frictional resistance Qs (10%) of each single pile (neglect group efficiency). Take effective earth pressure coefficient K = 1.4, ’ = (1/2)’, critical depth of pile Lcr (for Qp) = d = 1000 mm D = 400 mm L’ (for Qs) = 20D, Nq* = 21. [* i.e. for Qp at a depth over critical depth, using effective overburden stress at critical depth to calculate ultimate point bearing capacity] (b) If the piles are embedded in saturated homogeneous clay (su = 50 kN/m2), determine the ultimate load-carrying capacity Qu of the pile group regarded (i) as individual piles (10%) and (ii) as a block (10%), respectively. Use method to determine Qs. Bearing capacity factor Nc* = 9 both for single pile and block. (c) Following (b), determine the allowable load-carrying capacity Qall of the pile group considering long-term loading condition (5%).
d> = 1000 mm D = 400 mm Su P. CE 3. The plan view of a pile group is given in the figure (pile length = 16 m). (a) If the piles are embedded in sandy ground (@'= 30° and c'= 0) with groundwater table at a depth of 3 m (for depth = 3 m, y= 17 kN/mº; for depth > 3 m, Ysat = 19 kN/mº), determine: (i) the ultimate point load Qp (10%) and (ii) the frictional resistance Qs (10%) of each single pile (neglect group efficiency). Take effective earth pressure coefficient K = 1.4, S'=(1/2)', critical depth of pile Ler (for Qp) = L’(for Qs) = 20D, No* = 21. [** Rete i.e. for Qp at a depth over critical depth, using effective overburden stress at critical depth to calculate ultimate point bearing capacity] (b) If the piles are embedded in saturated homogeneous clay (su = 50 kN/m²), determine the ultimate load-carrying capacity Qu of the pile group regarded (i) as individual piles (10%) and (ii) as a block (10%), respectively. Use a method to determine Qs. Bearing capacity factor Nc* = 9 both for single pile and block. (c) Following (b), determine the allowable load-carrying capacity Qall of the pile group considering long-term loading condition (5%). < 0.1 0.2 0.3 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.4 2.8 1.00 0.92 0.82 0.74 0.62 0.54 0.48 0.42 0.40 0.38 0.36 0.35 0.34 0.34 Note: Pa = atmospheric pressure 100 kN/m2