a) b) c) Explain how you can represent the distribution of pore water pressure in an oedometer sample at any given time after an increase in external loading. Give the definition of the over-consolidation ratio and explain its importance to civil engineering applications. The results obtained from an oedometer test on a sample of clay are given in Table 2 below: Table 2 o'v (kPa) 160 200 320 640 480 320 Void ratio e 1.138 1.089 0.983 0.830 0.842 0.857 i) Plot a graph of the specific volume against the natural logarithm of the vertical effective stress. Indicate the one-dimensional normal compression line on the graph. ii) Calculate the pre-consolidation pressure and determine the slopes of the one-dimensional normal compression and unloading/reloading lines. iii) A 12m thick layer of this clay lies below a layer of sand of 10m depth from the ground surface. The water table is at the ground surface. The saturated unit weight of both soil layers is 20kN/m³. A new office building will be constructed at this site. The building will have a raft foundation which will increase the vertical effective stress in the clay layer by (40+4-X) kPa throughout its depth. A soil sample with an initial height of 20mm was taken from the mid-depth of the clay layer (i.e. 16m below ground level) and was tested in the oedometer apparatus; the results obtained are given in Table 2. Assuming the unit weight of water is equal to 10kN/m³, determine the final settlement due to the consolidation of the clay.