多孔介质中化学–热–水力–力学耦合过程本构模型和数值模拟

A constitutive model and numerical simulation for coupled chemo-thermo-hydro-mechanical process in porous media

本文发展了一个多孔介质中的化学–热–水力–力学(CTHM)耦合本构模型。该模型基于文献[1]中多孔介质热–水力–力学(THM)本构模型、文献[2,3]中的污染物传输本构模型和文献[4]提出的化学–力学本构模型。在本构模型中引入化学软化函数以模拟孔隙水中有机污染物对多孔介质力学性质的影响。考虑了温度对污染物传输机制的影响。本文CTHM耦合本构模型已在多孔介质的热–水力–力学–污染物传输数学模型中建立。在CTHM本构模拟框架中对计及化学塑性效应、描述在热–水力–污染物传输耦合作用下多孔介质力学行为、在应力–吸力–温度四维空间中包含了五重屈服面的耦合本构模型发展了一致性切线模量矩阵。数值结果突出显示了污染物浓度在多孔介质化学–热–水力–力学(CTHM)耦合系统中的影响。

A coupled chemo-thermo-hydro-mechanical (CTHM) constitutive model of porous media is developed in this paper. The model is developed on the basis of the following existing component constitutive models for porous media, i.e., the thermo-hydro-mechanical (THM) constitutive model presented in Reference[1], the constitutive model of contaminant transport presented in References[2,3] and the chemo-mechanical constitutive model presented in Reference[4]. The chemo-softening function is introduced into the constitutive model to simulate the effects of organic contaminants in pore water on the mechanical properties of the porous media. The effect of temperature on the mechanism governing contaminant transport in porous media is considered. The present coupled CTHM constitutive model has been integrated into the coupled thermo-hydro-mechanical mathematical model including contaminant in porous media. Within the framework of CTHM constitutive model, a consistent tangent modulus matrix for the fivefold yield surfaces in the four dimensional stress-suction-temperature space, describing the mechanical behavior of porous media coupled with thermo-hydro process and contaminant transport and taking into account the chemo-plastic effect, is derived. The numerical results are illustrated to particularly emphasize the effects of the contaminant concentration on the coupled CTHM system in porous media.