K0-determination by stress path triaxial apparatus with bender element

The coefficient of lateral earth pressure at rest K0 of Shanghai soft clay is measured by the GDS stress path triaxial device. The shear wave velocity and the corresponding small strain shear stiffness at K0 state are also determined by the bender elements planned in the triaxial apparatus. The functional relationship between the maximum shear modulus G0 and the isotropic confining pressure is established, and then the functional relationship between G0 and K0 is deduced. The possibility of using G0 to calculate K0 is investigated. Meanwhile, the value of G0 at isotropic stress state is also measured and that of K0 is back calculated based on the values of G0 at isotropic stress state and K0 stress state. The results indicate that the dissipation of the excessive pore water pressure during the K0-measurement is very important to obtain the reliable value of K0. Meanwhile, the back calculated values of K0 based on the G0-measurement agree well with the directly measured ones, which indicates the feasibility of K0-determination based on the field shear wave velocity.