Taking fully grouted rock bolt of underground caverns as research object, the load transfer mechanism of the bolt and surrounding rock was analyzed, and the basic differential equation of load transfer was deduced. The finite difference method was used to solve the equation combined with free deformation of the rock. Then the distributions for axial force and interfacial shear stress of anchorage body along the bolt length were obtained. The interfacial mechanical property of anchorage body was described by the two-line shear slip model. The stress of anchorage body was modified by constantly updating the displacement of the rock, considering transforming the excess interfacial shear stress into nodal load of the model after anchorage body slips. The pull-out test was simulated based on the bolt algorithm. The results show that the algorithm is reasonable and feasible. By analyzing the force of a characteristic bolt in a diversion tunnel, the influences of elastic modulus of the rock, interfacial shear stiffness, thickness of mortar, diameter and length of the bolt on the force of anchorage body were calculated. The results can provide theoretical basis for optimizing the layout of the bolts in underground caverns. © 2017, Editorial Board of Journal of Huazhong University of Science and Technology. All right reserved.
