Evaluation of liquefaction strength of Japanese natural sandy soil using triaxial and simple shear tests

The aim of this note is to reexamine the stress and strain conditions of cyclic triaxial and cyclic simple shear tests for evaluating the liquefaction strength of natural sandy soil. The conventional method of determining the liquefaction strength relies on the shear stress components. However, the use of stress invariants eliminates the need to specify the stress components, thereby making it a more rational approach for determining the liquefaction strength. A comparison of the results using the conventional stress ratio and the stress invariant ratio is done in this study. A strong correlation is seen between the liquefaction strengths obtained from the triaxial and the simple shear tests when using the stress invariant ratio. Despite this strong correlation, large scattering still remains due to the effects of the soil fabric of the natural sandy soil. A torsional hollow cylindrical device is used here to perform simple shear tests on undisturbed natural sandy soil.