Failure process of saturated granite residual soil slope: a 3D viscoelastic-plastic finite element modeling approach with nonstationary parameter creep

Accurately evaluating the failure process of soil slope can mitigate its negative influence on both human lives and economic loss. However, it is still a very difficult and important task. In this paper, a novel nonlinear rheological model with nonstationary parameter creep (NPCNRM) was proposed to represent the tertiary creep characteristics of slope soil. One-dimensional constitutive equations and three-dimensional (3D) model of NPCNRM were derived, and its 3D finite element program was developed in Fortran. The feasibility of the proposed model was partially verified by the uniaxial creep test of argillaceous slate. Through the application of Liangyeshan landslide located in Wuping county, Fujian province, China, the results show that using the proposed model can scientifically evaluate the creep failure mechanism of saturated granite residual soil slope; the accelerated creep of soil near the top of the slope is more significant than that at slope toe, which will aggravate the disintegration and loosening of soil and the continuous infiltration of rainfall, and then leads to further deterioration of soil strength.