不同侧压系数下各向异性巷道围岩破坏模式研究

针对各向异性初始应力状态(不同的侧压力系数下)的岩体巷道开挖问题,利用复合材料的Hoffman强度准则考察各向异性对巷道周围应力、位移和塑性破坏区的影响.结果表明:巷道围岩的最大主应力与侧压系数无关,当θ=30°~60°时为最大,θ=0°,90°时为最小.随θ的增加,巷道围岩的水平位移增加,垂直位移减小.在各向异性岩体中强度较大的方向与最大应力方向一致时,破坏发生在此方向,塑性破坏区的范围为最大.

Influence of Anisotropy on Failure Mode of Tunnel Under Different Lateral Pressures

For the rock tunnel under anisotropic state of geo-stress(with different lateral pressure coefficients),the influence of the displacement,stress and plastic zone around tunnel were examined with Hoffman yield criterion used for composite material.The results showed that maximum principal stress around tunnel has a maximum value for θ=30°~60° and minimum one for θ=0° and 90°,being independent of lateral pressure coefficients.With the increase value of θ,the horizontal displacement around tunnel increases and vertical one decreases.When the lateral pressure coefficient is smaller than 1,both roof and bottom are mainly failed,independent of θ.In the anisotropic material,when the direction with respect to the largest strength is coincident with the direction of major principal stress,the failure occurs in this direction,with largest plastic zone area.