Experimental Study On Roof Collapse Caused By Rockburst In Deep Driving Coal Roadway Based On Multi-source Information

In recent years,rockburst accidents are becoming more and more serious in deep driving coal roadways.Supported by the Key Project National Natural Science Foundation "deep mining and tunnel surrounding rock structure stability control information theory(51734009)" and National Natural Science Foundation of China "deep heading coal roadway impact roof falling multi-scale effect disaster mechanism research(52074259)",taking the roof collapse of the deep excavation coal roadway as the background,this paper firstly adopted the integrated “acoustic-electrical-wave” testing device to measure the multi-parameter precursory information during the failure and instability of the coal and rock.Then,the large-scale 3D physical simulation system was used to reveal the impact disaster mechanism and failure mode of deep heading coal roadway under the dynamic and static load.Finally,the discrete element numerical soft is used to reveal the evolution law of crack propagation and the formation and evolution mechanism of anchorage bearing structure.The main research contents and achievements are as follows:(1)The acoustic emission,resistivity,wave velocity and other multi-source information in the process of deformation and failure of different coal and rock mass under uniaxial load are synchronously collected through the self-designed“acoustic-electrical-wave” testing device.The internal relationship of acoustic emission ringing count,b-value,ultrasonic wave velocity,apparent resistivity and other precursor information was deeply analyzed.Based on multi-source information such as acoustic emission,ultrasonic and apparent resistivity,an early warning model of damage and instability of coal and rock is proposed.(2)A large-scale 3D simulation test system for researching the rockburst evolution and instability mechanism of roadway was independently developed.The test system can apply static and impact loads on the roadway through the hydraulic device and the explosion,respectively.Meanwhile,a variety of monitoring methods are integrated to realize the synchronous collection and joint supplement of various physical information in the loading process of physical models.The test system can be used for studying the mechanism of rockburst in the deep roadway and revealing the relationship between the strength of rockburst and the amount of surrounding rock that was thrown out,which can play a guiding role in the study of failure test of the different supporting roadway under dynamic and static load.(3)The response characteristics of stress field,deformation field and geoelectric field in the process of rockburst failure of different anchored roadways under the combined action of dynamic and static loads were studied by using the large-scale three-dimensional physical simulation test system.The mechanism and failure mode of rockburst failure of roadways with different supporting structures under the dynamic and static loads were revealed,and the instability criterion of roof anchorage structure of roadway under dynamic and static loads was proposed.(4)On the basis of the UDEC block discrete element numerical calculation method,the macro-and microfracture evolution mechanism of deep coal roadway under dynamic and static load is studied.The microdamage cracks are recorded and tracked by the compiled FISH program.The microcrack propagation and evolution law of surrounding rock of roadway under impact load is obtained,revealing the formation and evolution of anchorage bearing structure of surrounding rock of roadway under dynamic load.The influence of support mode,initial ground stress and dynamic load strength on impacting instability of roadway is analyzed systematically.The evolution laws of stress field,displacement field and crack field in impacting instability of roadway under different working conditions are compared and analyzed,and the impacting instability mechanism of deep driving coal roadway is revealed from the micro-level.(5)The comprehensive prevention and control strategy of "monitoring and early warning + active prevention and control" is put forward for safety control of the deep driving coal roadway.In order to provide a reference for the prevention and control of rockburst disaster in deep driving coal roadway,multi coupling analysis is used to comprehensively evaluate the risk degree of rockburst instability in deep driving coal roadway,and according to the risk degree of rockburst,classified anti-impact support measures are taken for different driving coal roadway.