Creep Fracture Characteristics of Fractured Rock Mass Strengthened with Toughened Epoxy Resin

Abstract

For improving the toughness and long-term strength of the fractured rock mass reinforced with epoxy resin and reducing the opening displacement of the crack tip, three types of converging cracks are established according to the deformation and failure characteristics of the rock mass, structural planes, and epoxy resin composite structure. The stress intensity factor of the type II compound crack and the analytical formula of the crack surface tip opening displacement are obtained. An improved Kelvin nonlinear creep model is proposed. Through the creep isochronous curve, the time and long-term strength of accelerated creep failure are obtained, as well as creep rupture coupling characteristics. The ductile plastic deformation is used to characterize the toughness, and the toughness of epoxy resin is enhanced by adding mud powder, and the relationship between toughness and long-term strength is established. Combined with experimental verification, when the drying mud powder content is 20%, the toughness of the epoxy resin has a good correlation with the long-term strength; when the mud powder content exceeds 30%, its ductility and long-term strength decrease, and at the same time the toughness effect is significantly weakened. The research results can provide a useful reference for toughened epoxy resin to strengthen fractured rock mass engineering.