Analysis of Deformation of Circular Roadway Considering Effects of Intermediate Principal Stress and Dilatancy

Abstract

Based on the unified strength theory and non-associated flow rule, with the consideration of the effects of intermediate principal stress and dilation characteristics, the analytical expressions of surrounding rock stress, displacement and plastic zone radius were obtained. Then the influences of the intermediate principal stresses and dilation angles on the surrounding rock stress, displacement and the plastic zone radius were analyzed by engineering example. The analysis shows that surrounding rock stress distribution and plastic zone radius have close relations with the intermediate principal stress. With the increase of the intermediate principal stress coefficient, the ultimate strength of surrounding rock increased, but the plastic zone radius shows a decreasing trend. The displacement of plastic zone is not only related to the intermediate principal stress coefficient, but also to the dilation angle. The displacement of plastic zone increased with the increase of dilation angle, and the displacement of plastic zone decreased with the increase of the intermediate principal stress coefficient.