隧道开挖的双重介质水力耦合模型有限元分析

基于混合物理论孔隙-裂隙岩体的双重孔隙介质水力耦合计算的微分方程，利用伽辽金有限元法提出了相应的有限元公式，并基于岩体分类指标（RQD，RMR）提出了与岩体应变状态相关的渗透系数计算公式。编制了裂隙岩体双重介质流固耦合的2-D有限元程序，给出的验证算例表明，该程序是合理和实用的。同时将该程序用于隧道开挖的模拟计算，探讨渗流效应对开挖隧道围岩变形与渗流场的影响。计算结果表明，在隧道设计中不考虑渗流的影响是偏于不安全的。

Dual-porosity media hydromechanical analyses of tunnel excavation

Based on mixture theory and the double porosity hydromechanical coupling concept, a set of coupled governing differential equations of porous fissured media is derived. The finite element technique has been employed as the numerical methods for solving these equations by using Galerkin finite element methods. Relations relating to rock classification rating RQD and RMR are developed to define changes in effective porosity and hydraulic conductivity that result from the redistribution of strains in disturbed rock mass. A 2-D finite element program and software for solving the double porosity media coupling model is developed. Results obtained from a hypothetical example indicate that the program is reasonable and practical. The program is also used to simulate tunnel excavation; the influence of seepage effect on tunnel ground deformation and seepage field is discussed. The results of numerical calculation show that tunnel liner design is unsafe without considering hydromechanical coupling effect.