基于渗透非线性的黏土岩热–水–力耦合效应研究

Coupled thermo-hydro-mechanical response of argillite rock based on nonlinear seepage behavoir

在多孔介质的热–水–力耦合分析中,孔隙率和孔隙水的黏滞性是影响渗透性的主要因素。通过研究孔隙率和孔隙水黏滞性的改变规律,在数值分析时,引入了孔隙率随应力改变和孔隙水黏滞性随温度改变的渗透非线性分析方法。同时研究了数值分析中温度荷载作用下应力边界条件和位移边界条件对温度应力的影响。研究结果表明:温度荷载作用下,数值分析时采用应力约束边界比位移约束边界更合理;考虑渗透非线性情况下得到的孔隙压力计算值与实测值更接近。

During the coupled thermal-hydro-mechanical analysis of porous media, the porosity and viscosity of porous water are the main factors affecting the permeability of the rock mass. Based on the variation law of porosity and viscosity of porous water undertaking loads, a method of stress-dependent porosity and temperature-dependent viscosity of porous water is developed during the numerical analysis. To investigate the influence of mechanical boundary conditions on the thermal stress, a comparison of the results between displacement boundary and stress boundary is made. The study indicates that the values of thermal stress and pore pressure obtained by stress boundary are smaller than those by displacement boundary.The calculated values of pore pressure taking nonlinear seepage behavior into account are closer to the measured ones.