层状岩体渗透特性多尺度演化模型研究

考虑层状岩体内部微裂纹、层面等不同尺度结构特征,采用两步均匀化方法,建立了层状岩体细观损伤模型与渗透特性多尺度演化模型。两步均匀化过程分别考虑了层状岩体内部细观结构与宏观结构对渗透特性的影响。层状岩体渗透特性演化模型可同时考虑微裂纹损伤扩展、滑移剪胀,层理面滑移磨损、剪胀演化特性以及微裂纹与层理面相互作用等特征,较好地反映了内部不同尺度微结构变化对其渗透特性演化的影响以及渗透特性的各向异性特征。基于该模型,通过数值模拟层状岩体中地下洞室开挖扰动过程,研究了层面倾角以及岩体强度各向异性特征对洞周围岩损伤与渗透特性演化规律的影响。研究成果对于深部层状岩体水–力耦合特性研究具有一定参考意义。

Multi-scale permeability evolution model for layered rocks

A damage constitutive model and a multi-scale permeability tensor model for layered rocks based on a two-step homogenization technique are proposed considering the characteristics of multi-scale structures (i.e., bedding planes and microcracks). With the homogenization technique, the proposed models wells account for the influences of anisotropic damage growth and mobilized dilatancy behavior of microcracks, mobilized degradation and shear dilatancy of bedding planes, and interaction between bedding planes and microcracks. The effects of structures with different scales on the variation of permeability are better addressed. Numerical simulations are performed on an underground cavern in layered rock masses to investigate the changes in multi-scale hydraulic conductivities under excavation, which are influenced by the anisotropic strength characteristics of layered rocks and inclination angles of bedding planes. The results may provide a helpful reference for better understanding the coupled hydro-mechanical behaviours of deep rocks.