Laboratory Studies on the Sensitivity of Layer No.4 Soft Clay in Shanghai

Abstract:

The sensitivity of layer No.4 soft clay in Shanghai was investigated by unconfined compression test, laboratory mini vane shear test and field vane shear test. The thixotropy test lasting for about half one year was conducted to evaluate the effect of the thixotropy on the sensitivity for the soil. Results show that the sensitivities obtained by unconfined compression test is about 1.8 times that obtained by field vane shear test, smaller strength obtained by hand remolding method than the vane remolding method is the major reason that cause the huge difference between the results obtained by the two kinds of test. Therefore, the sensitivity measured by field vane shear test can’t be used directly to evaluate the sensitivity for the soil. The thixotropy test show the contribution of thixotropy on sensitivity of Shanghai soft clay can’t be neglected and the thixotropy contributes at least 1/3 on the sensitivity that measured by unconfined compression test.

Key words:soft clay; sensitivity; thixotropy; strength