The Peacock diagram (Fig. 12.11) has been used to predict the pore pressure response of...

The Peacock diagram (Fig. 12.11) has been used to predict the pore pressure response of undrained tests on sand, based on the volume changes observed at failure in drained tests. At a given void ratio a sample consolidated at an effective confining pressure less than would be expected to offer more resistance to liquefaction (since it should have a dilative tendency and therefore develop negative pore water pressure) than a sample consolidated at a confining pressure higher than (as this one should tend to decrease in volume during shear).This is contrary to what has been found in the laboratory in cyclic triaxial tests. Explain the apparent contradiction.

Reference: Fig. 12.11