Analyses of dilatancy characteristics of cemented soils based on triaxial test and numerical simulation

Abstract

In construction engineering, cement-treated soil, such as the column, is commonly applied to improve soft soil foundation. It is found that the dilatancy usually occurs in cemented soils when they are at failure by shear, and the dilatancy behavior shows nonlinear characteristics. However, the constant dilatancy angle model based on Mohr-Coulomb strength theory at present cannot correctly express the nonlinear volume change behavior. Thus, triaxial tests of cemented soils with different cement mixing ratios and confining pressure were carried out. A model of dilatancy angle was established using plastic mechanics theory, which could simultaneously consider the effect of uniaxial compressive strength, mean stress, and equivalent plastic strain. And then, the model of the dilatancy angle is verified by numerical simulation using finite element technology. The results show that the stress-strain curves of the cemented soils in the triaxial test are softening types, and the volume expansion phenomenon is observed when the cemented soils are damaged. The dilatancy behavior of cemented soils is usually quantified by the dilatancy angle. If the dilatancy angle is taken as a constant value, the dilatancy of cemented soils may be overestimated or underestimated, which cannot correctly reflect the nonlinear volume change law after the peak strength. The dilatancy angle model considering the influence of mean stress and equivalent plastic strain, can reasonably express the nonlinear volume change behavior of cemented soils after the peak strength, and the simulation results are in good agreement with the test results.