单裂隙水流对岩体裂隙法向刚度的影响研究

Influence of Single Fracture Flow on the Rock Fissures Normal Stiffness

岩体边坡工程与地下工程稳定性主要依赖岩体中的节理、裂隙、软弱夹层等结构面的力学性态。基于岩体低渗透性与结构面导水性,采用广义双重介质模型,对孔隙空间建立非饱和渗流HM耦合方程。对饱水/干燥裂隙空间建立裂隙受压体积变化的HM耦合方程。通过考虑孔隙和裂隙界面处压力连续,实现两处模型在应力边界上的耦合。对开口裂隙、封闭裂隙、半开半闭裂隙岩体的非饱和渗流过程进行了数值模拟计算。由计算结果得知:裂隙的闭合程度影响裂隙水向孔隙消散,从而影响裂隙刚度;在正应力作用下,裂隙受压逐渐分段闭合,由于裂隙的不同位置具有不同的刚度特征,整条裂隙不具同步性,甚至由于裂隙面性质不同,刚度变化甚至出现反复性。

The stability of rock slope engineering and underground engineering mainly depends on the mechanical behavior of joint,fissure and weak intercalated layer in rock mass structure. Based on the low permeability of rock and the water conductivity of structural surface,unsaturated seepage HM coupled equations of the pore space were created using generalized double medium model. HM coupled equations of saturated / dry cracks space on the changing volume of cracks under pressure were also created. Considering the continuous pressure of the pores and cracks at the interface,coupling of the two models on the stress boundary was achieved. Numerical simulation of mass unsaturated seepage process of opening fracture,closed fracture,and half opening-half closed fracture rock was conducted. It can be known from the calculation results： The closure degree of fracture affects the crack stiffness because it influences the dissipation of pore-water; Fractures gradually piecewise close under normal stress; Because of the different stiffness characteristics in the different position of fracture,the fracture is not synchronous; Changing of stiffness even repeats due to the different fracture properties.