Study On The Crack Evolution Of Coal-rock Interface When Combined Body Is Fractured Under Load

As many coal mines in China gradually enter the stage of deep high-strength mining,many gas dynamic disasters seriously restrict the safety of mine production.In this paper,four types of coal and rock combination models were designed to make the combination,and combined with digital image analysis and energ theory,mechanical and acoustic emission characteristics experiments of coal and rock combinalion under uniaxial load were carried out,and the following preliminary results were obtained:(1)The use of independent research and develop ment of square specimen mold and its supporting type of coal and rock malerial specimen quantitative combination production of coal and rock specimen preparation system,carried out under the condition of different combinations of coal rock characteristics of the combination of uniaxial compression experiment,the different coal and rock combination whole stress-strain curves of the specimens,the compressive strength,peak strain and elastic modulus etc.Characteristics.(2)XTDIC system was used to analyze the behavior of fracture formation,expansion,development and connection in the process of full stress and strain of coal and rock mass under different combination conditions,and the evolution law of strain field and displacement field and the evolution law of displacement field in the process of full stress and strain of specimens of different types of combined mass was obtained.(3)The high-defnition monitoring system is used to monitor the whole stretch stress-strain process of coal-like rock assemblage.Combined with the whole stress-strain process,the evolution law of interface cracks in the static loading failure process of the assemblage specimen is analyzed,and the evolution characterstics of interface cracks in the whole process of failure and deformation are obtained.(4)The acoustic emission signal acquisition system was used to monitor the acoustic emission behavior during the deformation and failure process of coal and rock mass under different combination conditions.The relationship between the fracture evolution process at the interface of coal and rock mass and the acoustic emission parameters was further analyzed based on the fracture image evolution law of coal and rock mass specimen.Through the above research,this paper analyzes the different types of coal and rock under dead load combination rupture characteristics of the interface crack in the process of evolution,the evolution characteristics of strain field,displacement field in the process of the evolution of crack and evolution characteristics of acoustic emission parameters and the evolution of energy law,to explore coal and rock fracture network development law laid a solid foundation,which provides the theoretical basis of pressure relief gas extraction.