A 5 m thick doubly drained normally consolidated clay layer at a site has e_o = 0.95, C_c = 0.54, and c_v = 4.0 m²/year. The effective overburden pressure at the middle of the clay layer is 70.0 kN/m². Some proposed construction work is expected to impose a 60.0 kN/m² load at the ground level.

a. Determine the primary consolidation settlement.

b. Noting that the expected primary consolidation settlement is high, it is proposed to apply a surcharge over a period of one year. What should the magnitude of this temporary surcharge be so there will be no postconstruction consolidation settlement?