A 15 m thick normally consolidated clay layer is shown in Figure 13.63. The liquid limit and

Question:

A 15 m thick normally consolidated clay layer is shown in Figure 13.63. The liquid limit and plastic limit of the soil are 39 and 20, respectively.
a. Using Eq. (13.53) given by Skempton (1957), estimate the undrained cohesion at a depth of 11 m below the ground surface as would be obtained by conducting a vane shear test.

b. Using Bjerrum’s (1974) correction factor [Eqs. (13.71) and (13.72)], estimate the design value of the undrained shear strength determined in Part a.

c. If the clay has the potential of becoming overconsolidated up to OCR 5 3.0 due to future ground improvement activities, what would be the new undrained cohesion? Use Eq. (13.54) given by Ladd et al. (1977).