2D Semimodel of Full-Section Anchorage in Thick Soft Rock Roadway

This paper focuses on the reinforcement effect of full-face anchorage in thick soft rock roadway. A 2D semimodel of full-face anchorage in roadway with thick surrounding soft rock was proposed firstly by transforming the confinement effect of the excavation face in the longitudinal direction as the virtual internal support force at the circumferential surface. Then, based on the theory of elasticity, the theoretical model of the coupling effect between surrounding rock and anchoring system was established, and the analytical solutions of stress and displacement were obtained employing superposition principle. Finally, the theoretical solution was verified by numerical simulation, and the distribution laws of stress release-anchor stock-surrounding rock coupling were analyzed in detail considering stress release. Results demonstrated that the stress field of the surrounding rock diverse widely with different stress release coefficients. With the increasing of stress release coefficient, the radial stress of the surrounding rock decreases, while the tangential stress increases. The supporting role of the bolt is mainly reflected in improving the radial stress of the anchorage zone. However, it has little effect on the tangential stress. What is more, the anchoring effect is more significant to soft rock stress than hard rock. In addition, the prestress of rock bolt has a certain matching relation with the bolt parameters, the surrounding rock parameters, and the initial stress. This study laid a theoretical foundation for further analysis of the interaction between surrounding rock and bolt supporting in plastic zone.