Study On The Mechanical Response Regularity Of Media Properties Of Surrounding Rock In Stope

Under the effect of mining pressure,the properties of surrounding rock media gradually transformed from continuous bodies without mining disturbances to discrete bodies that are damaged by severe mining disturbances,the key issues related to the surrounding rock media properties need further study.Therefore,the comprehensive research methods like laboratory tests,theoretical analysis,numerical simulation and field measurement are adopted in this dissertation to study specifically on the transformation regularities and mechanical features of media property of surrounding rock,prevention and control technology of dynamic disaster of gassy coal.The main research results are as follows:The relations between damage state and sound speed of coal and rock are obtained through the test of acoustic properties of loaded coal and rock.Media property transformation factor K is defined,and it is put forward to use the media property transformation factor as the indicators of identifying the media property.The transformation regularities of media property are described,and the thresholds for quantitatively dividing media properties are given.For different damaged states of coal,based on the transformation regularities of media properties and the evolution features of crack distribution,the coal-rock constitutive relations of different media properties are theoretically deduced.The theoretical description of coal-rock stress-strain relationship of different media properties is realized,and the response regularities of damaged coal rock in different stress environments are clarified.By adopting the discrete element method that based on continuum mechanics,and by combining the coal-rock constitutive relations of different media properties and the transformation regularities of media properties,the three-dimensional stress distribution features of surrounding rock of the stope based on the transformation of media properties are studied.The essential connection and evolution regularities between characteristic zone of surrounding rock stress and the state of media properties of surrounding rock are revealed.Through field test and theoretical analysis,the correlation and regularity of the mining stress,gas pressure distribution and media properties of coal body in front of the panel which contains coal gas are discovered.The dynamic disaster prevention and control technology based on the media properties is proposed,and by applying to the engineering,it has been effectively verifiedFigure[68]Table[8]Reference[149]...