Assignment # 1: Marks : 100

Q.1 The critical state line or steady state line for Sydney sand in *e**-log(*p*¢) is given by the following equation:

(1)

Using the concept of critical state concept, identify whether the following site would be liquefied due to cyclic instability. Plot the graph for y* vs depth with a y*=0 line. [Marks: 25]

Fig. 1: Soil profile for question 1

- 2: Based on “CPT modified data” estimate liquefaction potential and plot the three graphs as given in “Example liquefaction resistance SPT”. [Marks: 50]

Note, use Q and F for soil classification and show iterations for exponent “*n*” in *I _{c} *calculation.

Assume, g=20kN/m

^{3}, water table 1.0m below the surface, a

_{max}=0.10g and Mw=7.0

Any other parameter may be assumed as SPT example.

Q.3: Use Been et al. (1987) approach to calculate y from CPT data and estimate liquefaction potential under critical state soil mechanics. [Marks: 25]

Produce a plot as in Q.1.

What are current assumptions for this approach and how can be overcome?