Abstract:In order to better study the overall stability of surrounding rock under non-uniform stress field, the stress around surrounding rock is divided into two parts for superposition according to the model characteristics of surrounding rock under non-uniform stress field.Based on the d-p criterion and the ideal elastic-plastic constitutive relation, the analytical expression of surrounding rock stress in the elastic zone of circular tunnel under non-uniform stress field is derived by using the biharmonic equation and the semi-inverse solution method, and the theoretical analysis results are verified by Flac3D numerical simulation.The results show that when considering the influence of intermediate principal stress coefficient, the larger the intermediate principal stress coefficient is, the smaller the range of lateral pressure coefficient is.The larger the lateral pressure coefficient, the lower the concentrated stress of the tunnel, the higher the concentrated stress of the arch.At the same time, the theoretical analysis results are basically consistent with the numerical simulation results.The mechanical model considering the non-uniform stress field distribution more accurately reflects the stress distribution characteristics of surrounding rock and has certain reference value for the supporting scheme of surrounding rock.