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深部岩体具有典型的不均匀、不连续的自应力块系等级构造结构。由于浅部巷道围岩应力场分析是基于连续介质力学理论,没有考虑岩体的块体特性,因而无法应用于深部巷道块系围岩的应力场分析。考虑到深部巷道块系围岩破坏类型主要表现为峰后岩块沿软弱接触面的剪切滑移破坏,通过建立深部巷道的平面应变块系围岩模型,得到了轴对称条件下岩块相互作用的解析解;分别假设岩块之间的接触满足刚塑性和Mohr-Coulomb屈服条件,推导得出上述两种屈服条件下的块系围岩模型和连续介质模型的围岩支护力的计算公式。对比分析表明:围岩块体构造特性对深部巷道施工和承载力设计计算有重要的影响;通过假设块体间剪应力与剪切滑移满足分段线性关系,得到了块系围岩径向位移,剪应力和剪切滑移量的解析表达式,引入无量纲化的深部巷道块系围岩稳定性参数λ,并得出当λ<1时块系围岩是稳定的,当λ>1时块系围岩是不稳定的。
Deep rock mass has a typical heterogeneous, discontinuous self-stress block hierarchy structure. As the stress field analysis of the surrounding rock of shallow roadway is based on the theory of continuum mechanics, it can not be applied to the stress field analysis of the surrounding rock of deep alluvium. Considering that the type of surrounding rock failure in deep alluvial blocks is mainly the shear slip damage along the weak contact surface of the post-peak rock mass, the rock mass is obtained under the axial symmetry condition by establishing the surrounding rock model of the plane strain block in the deep alleyway. Respectively. Assuming that the contact between the rock blocks satisfies the rigid plasticity and the Mohr-Coulomb yielding conditions respectively, the calculation of the surrounding rock supporting force for the bulk rock mass model and continuous medium model under the two yield conditions is derived formula. The comparative analysis shows that the structural characteristics of the surrounding rock mass have an important influence on the design and calculation of the construction and bearing capacity of the deep roadway. The linear relationship between the shear stress and the shear slip satisfies the piecewise linear relationship, Displacement, shear stress and shear slippage, the stability parameter λ of surrounding rock without block is introduced, and the result shows that the block surrounding rock is stable when λ <1, when λ> 1 block rock is unstable.