Question

The proposed new railway line is shown in Figure 1. The ground in the construction site consists of an expansive clay layer underline by the proposed 2m thick embankment fill (designed in Part A). A coarse-grained sand layer sitting on a hard rock could be found below the clay layer. Some physical properties of the soil layers available in the ground are given in Table 1. With considering potential extreme seasonal change in this area;

Q) Calculate the possible vertical settlements at points A, B, C and D (along the railway line) with considering the potential extreme seasonal change from the wettest to the driest (please note that each soil layer is extensively long (≥ 20 km) and thus lateral movement of the soil has been restricted by the surrounding soil)

Answer 1