In less than 50 words, state the principle of effective stress. The results for a consolidation test on an undisturbed sample of clayey soil are shown in Figures 4(a) and

4(b).The initial dimensions of the tested soil sample were 75 mm indiameter and 20 mm in height. i) From Figures 4A and 4B, and in less than 100 words, identify the method and select the plot that you should use for determining the consolidation rate for the soil. Justify your answer. ii) Determine the consolidation rate for the soil. In less than 200 words, explain the difference between drained,undrained and quick undrained triaxial tests. Which type of test would be better suited for determining the soil strength parameters necessary for the design of an earth dam? Justify your answer. The Mohr-Coulomb failure criterion is simple and useful but has some limitations in describing soil behaviour. An alternative approach was developed in the 1950s: "Critical State Soil Mechanics".