Answer Happy

Question 1 (15 marks) Safe bearing capacity - (qu(net)/F) + yz Terzaghi bearing capacity equations for circular and square footings: (Circular) qu(net) = 1.3cN+yz(N-1) + 0.3yBN, (B is the diameter) qu(net) = 1.3cN+yz(N-1) + 0.4YBN, (Square) INB: Obtain Terzaghi bearing capacity coefficients from the chart supplied] (a) Calculate the gross applied stress (Pgross) and net applied stress (Pnet) at the base of the foundation shown below for (i) bearing capacity analyses on the basis of total stress, and (ii) settlement analyses. (4 marks) Water table Weight - 25MN XXX 2m Ysat = 20 kN/m² Yw = 10 kN/m² 8m x 8m (b) (i) A 3 m square pad footing transfers a gross load (column, self-weight and backfill) of 3000 KN to the underlying soil. It is founded at a depth of I m in a dry sandy soil for which = 30⁰ and ya = 18 kN/m³. Calculate the gross and net applied pressure at the base of the footing, and hence the factor of safety (FoS) against a bearing capacity failure (NB: use the relevant Terzaghi equation). (ii) Briefly explain the procedure of determining the ultimate bearing capacity using the plate loading test results. (4+3-7 marks) (c) A water tank of diameter 10 m applies a total load of 20 MN at 2 m depth in a clay soil for which C₁ = 75 kN/m², 0 = 0° and y = 20 kN/m³. Calculate the gross and net applied pressure on the soil, and the factor of safety against a bearing capacity failure (NB: use the relevant Terzaghi equation and Skempton's chart to find Ne). (4 marks)