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用西原模型描述双重孔隙-裂隙介质的流变特性,但其中的瞬弹、粘弹及粘塑性元件由岩块和节理的成分构成,建立了该模型的平面有限元求解格式并引入已开发的计算程序中.针对一个矩形地下洞室围岩中无、有成组正交或斜交裂隙的四种计算方案,进行数值模拟,分析、对比了围岩中的位移、应力及塑性区.其结果显示:多组裂隙的作用一是降低了完整岩体的抗剪强度,二是改变了围岩中的应力分布及量值;与单一介质相比,双重介质围岩中位移的方向有所变化,其随时间发展的量值明显增大,并且应力场的分布也有相应的改观;随裂隙组倾角的改变,双重介质围岩中的塑性区范围可能比单一介质围岩中的大或小.
The Nishihara model is used to describe the rheological properties of the double porosity-fractured media. However, the instantaneous shells, viscoelastic and visco-plastic elements are composed of rock masses and joints. The planar finite element solution format of the model is established and introduced In the calculation program, four kinds of calculation schemes such as no group of groups of orthogonal or skewed cracks in a rectangular underground cavern are simulated and analyzed, and the displacement, stress and plastic zone in surrounding rock are compared. The results show that the effect of multiple sets of fractures is to reduce the shear strength of intact rock mass and to change the stress distribution and magnitude in surrounding rock. Compared with single medium, the direction of displacement in double medium surrounding rock is different The magnitude of its development over time significantly increases and the distribution of stress field also changes accordingly. With the change of dip angle of the fracture group, the plastic zone in the double medium surrounding rock may be larger or smaller than the single medium wall rock .