Study On Rock Friction Sliding Instability Mechanism And Acoustic Emission Evolution Characteristics

Friction sliding was one of the main characteristics of deformation and failure of rock with discontinuities plane.Engineering disasters caused by friction sliding instability of rock with discontinuities plane frequently,which was greatly threatened to geotechnical engineering construction such as transportation,mining,water resources and hydropower engineering.In this paper,experimental method and numerical method were used to analyze the evolution characteristics of deformation field and acoustic emission index during rock friction sliding.The mechanism of rock friction sliding instability and the evolution characteristics of acoustic emission were summarized to provide reference for the prediction,early warning and prevention of geotechnical engineering disasters.The paper of experimental method was rock double-sided shear friction model.The experimental observation systems were composed of digital speckle correlation methods and acoustic emission systems to study deformation field of in different stages of rock frictional sliding.The evolution characteristics of rock friction sliding displacement field,interface sliding displacement and interface sliding rate,and the deformation energy density of the rock were studied.The displacement contours characteristic of sliding rock blocks in sliding area and locking area were obtained.With the increase of occurrence times of stick-slip,the sliding velocity curve showed obvious multi-peak evolution characteristics.In the shear stress linear increase middle and late stage,the accumulation period and release period of rock deformation energy were alternately evolved.The viewpoint that the interface inhomogeneous deformation caused rock frictional sliding instability was proposed.The rationality of this viewpoint was verified by analysing evolution characteristics of the rock friction sliding deformation inhomogeneous index.Theoretical analysis was carried out systematically to study mechanism of rock friction sliding instability by spring-block model.It was founded that the value of shear force drop in the stick-slip stage and the duration of locking stage and the value of interface friction force in the time of interface micro-slip start-up were correlated with the interface inhomogeneous.The evolution characteristics of acoustic emission ringing count,acoustic emission cumulative energy and acoustic emission b-value under different loading rates were analyzed in this paper.The result show that,the acoustic emission ringing count was influenced by rock interface frictional sliding velocity.The acoustic emission cumulative energy was related to the rock interface sliding displacement.The evolution stage of acoustic emission b value and the evolution stage of deformation energy density were corresponding to each other.