圆形巷道围岩蠕变位移解析解及支护反力影响分析

The rheological characteristics of rock mass are important factors causing deformation of tunnel surrounding rock. In order to describe the rheological characteristics of circular tunnel surrounding rock, the constitutive model of rock mass is assumed to be a visco-elasto-plastic model combining the Burgers model and the unified strength criterion. Considering the influence of intermediate principal stress coefficient and support force, the creep displacement analytical solution of tunnel surrounding rock is derived through the elastic strain equation, with the introduction of time characteristics. Combined with the numerical analysis, the influence of intermediate principal stress and support force on the plastic zone radius of tunnel surrounding rock, as well as the stress and displacement fields, is analyzed. The variation law of displacement field with time is also studied. The results show that increasing the intermediate principal stress and support force can reduce the plastic zone radius and rock mass displacement, and improve the stability of tunnel surrounding rock. With the increase of time, the deformation of rock mass gradually increases. However, by increasing the support force, the deformation rate of rock mass can be effectively suppressed, which alleviates the deformations to a certain extent.