Thermal Contraction of Saturated Normally Consolidated Clay Based on Thermo-Hydro-Mechanical Numerical Simulation

Abstract:

Many experimental studies on the thermal consolidation of saturated normal-consolidated soil show that the volume change of the soil has a thermal compression behavior when the temperature increases， which is contrary to the principle of thermal expansion and contraction. To solve this problem， a numerical simulation of the thermal consolidation test of saturated normally consolidated soil was conducted by the thermal-hydro-mechanical （THM） fully coupled finite element program in this paper. Because the thermal conductivity and permeability of clay are relatively small， in the heating process， a temperature difference will occur inside the sample， which will cause excess pore water pressure， and finally the soil will show thermal contraction with the dissipation of the excess pore water pressure. When the permeability coefficient of the soil is increased， the excess pore water pressure is not generated inside the soil， and the soil exhibits thermal expansion. Therefore， the thermal contraction phenomenon of saturated normally consolidated soil caused by the increase of temperature is not the basic mechanical property of the soil， but a boundary value problem.

Key words:heating test;thermo-hydro-mechanical numerical simulation;normally consolidated clay;thermo-elasto-viscoplastic constitutive model