双重介质温度场-渗流场-应力场耦合模型及三维数值研究

DUAL MEDIA MODEL FOR THERMO-HYDRO-MECHANICAL COUPLING AND 3D NUMERICAL SIMULATION

在建立双重介质温度场-渗流场-应力场耦合微分控制方程基础上,提出研究裂隙岩体温度场-渗流场-应力场耦合的双重介质模型,对不同介质分别建立以节点位移、水压力和温度为求解量的三维有限元格式,提出该数学模型的求解策略与方法,开发双重介质流固热耦合分析的计算程序,通过模拟地下2200m的高温岩体地热开发系统的算例发现,注入井附近温度场-渗流场-应力场三场耦合作用十分明显的,主干裂隙对渗流场、温度场和应力场的整体分布具显著影响。与渗流场-应力场耦合,应力场-温度场耦合进行比较,探讨各场耦合效应的强弱,可以得出,在一定空间、时间域内,往往存在着起主导控制作用的双场耦合系统,变温条件下温度场对裂隙渗流场具显著耦合作用,从而论证了存在温度变化梯度的岩土工程中进行三场耦合分析的重要性。

Based on the differential control equations of the coupled thermo-hydro-mechanical(THM) processes of dual media,this paper presented three-dimensional coupled model of dual media to research coupled THM of fractured rock masses. In the coupling model,the values of nodal displacement,water pressure and temperature were solved in different media. Strategy and methods to solve this mathematical model also were discussed. A three-dimensional FE codes for analysis of coupled THM processes of dual media were developed tentatively. Through the numerical computation for a coupling THM phenomenon in the heat exploitation of deep-seated HDR 2 200 m under the surface,it was shown:(1) coupling THM processes was obvious in the rock mass near injection wall;(2) trunk fractures will influence the distribution of seepage field,temperature field and stress field remarkably. Compared with hydro-mechanical coupled model and thermo-mechanical coupled model,the remarkable or unremarkable interactions between three fields were studied. It is also displayed:(1) dominant double coupling system occurs in the certain space time;(2) temperature field remarkably has effects on fracture seepage field under changeable temperature condition. The importance of coupled THM processes was highlighted.