Compressive Creep Property and Model for Unsaturated Argillaceous Siltstone

Abstract:

In this paper， the tertiary argillaceous siltaceous soft rock was extracted from a subway station construction site in Nanning， China. Triaxial compression creep tests were conducted and influences of water content on creep properties of the unsaturated argillaceous siltstone were analyzed. Meanwhile， a nonlinear viscoplastic component was embedded into a five-component viscoelastic model and a seven-component unsaturated compression creep model for the argillaceous siltstone was built. Using this model， the variations of the creep parameters were analyzed. The results show that as water content increases， the creep deformation and creep rate of the argillaceous siltstone significantly increase， while the long-term creep strength obviously decreases， indicating that water has an important impact on the creep deformation of the argillaceous siltstone. The newly built seven-component nonlinear viscoelastoplastic model well simulates the whole creep process curves.

Key words:unsaturated muddy siltstone;triaxial compression creep test;creep deformation;creep rate;creep long-term strength;nonlinear seven-element creep model