Study On The Evolution Process Of Fractures On Rock Slopes In Strong Seismic Areas Based On Fracture Mechanics

China is a country prone to earthquakes,and the slope instability caused by the impact of earthquakes poses a huge threat to people’s lives,property and safety.Because of the complex geological conditions,there are a large number of structural surfaces on the rock slope that affect their stability,and it is necessary to conduct targeted research especially in difficult and complex mountainous areas.Among the many methods for analyzing slope stability,although the most commonly used limit balance method has a good effect in calculating homogeneous soil slopes,due to the existence of a large number of structural surfaces inside the rock slopes,the calculation results cannot fully reflect the real engineering geological environment and rock mass structure characteristics.Based on the fracture network of the rock slope in the strong earthquake area,the relevant theory of fracture mechanics and the basic criterion of fracture propagation,this paper proposes a fracture propagation method that comprehensively considers the fracture propagation length,fracture propagation connection angle,energy gradient.In addition,a comprehensive study on the fracture propagation evolution process of the rock slope in the strong earthquake area is conducted,in order to provide an effective solution and necessary theoretical support for the stability analysis of the joint rock slope in the strong earthquake area.(1)Based on the Monte Carlo method,considering the factors such as fracture density,trace length and attitude,a two-dimensional discrete fracture network model of the slope that satisfies the engineering geological characteristics is established.The network model is imported into the finite element analysis software,and the stress intensity factor and J integral value of the crack tip of the complex network model are obtained by fracture mechanics.The fracture propagation method is established by considering the fracture propagation length,the fracture propagation connection angle,the energy gradient.Through the independent programming of secondary development,the fracture endpoints that meet the criterion are solved,and the cracks propagation in the rock slope under natural conditions are explored,and the potential slip surface is determined.(2)Based on the stability analysis results of the rock slope based on the strength reduction method,the potential slip surface in the rock slope is compared and analyzed,and the rationality of the crack propagation method established in this paper considering the crack propagation length,fracture expansion connection angle,energy gradient and other factors is verified.Acoording to the influence of seismic loads,an analysis model of crack propagation on the joint rocks slope in strong seismic zones based on fracture mechanics is established.(3)The crack propagation method based on fracture mechanics and the crack propagation analysis model of joint rock slope in the strong seismic area are applied to the Tangjiashan landslide,and the failure process is analyzed.This reserach provides a certain reference for the numerical calculation of rock slope stability under similar engineering geological conditions.