Research On The Complex Disaster Of Roadway Rock Burst And Roadway Roof Falling

In the coal mining,rock burst and roof falling disasters are often occur.However,sometimes two kinds of disasters often affect each other and cause disaster,which are manifested in a complex form,causing more serious damage.Therefore,this paper proposes the concept of rock burst and roof falling complex disasters,through field investigation,theoretical analysis and numerical simulation methods,the damage characteristics,occurrence mechanism and influencing factors of complex disaster is researched,using to provide reference for the prevention of complex disaster.Firstly,the classification of rock burst and roof falling are described.The characteristics of single disaster and complex disaster damage are researched from the perspective of mutual comparison,and the conclusions of the damaged parts in the roadway,the throwing characteristics,the damage characteristics of the support and the release of energy sources are obtained.Then the disturbance response instability mechanism of rock burst and the discriminant criterion are described,and obtained that therock burst will occur when the critical softening zone depth or critical load is reached.By analyzing the radius of the critical softening zone and the variation law of the critical load with E/?,it is easy to occer rock burst when E/? is small.And the greater the value of E/?,the greater the influence of the support on the critical load,and the increase of the support resistance can increase the critical load.Then the elastoplastic zone calculation and analysis of the roadway roof falling is carried out,and the radius of the plastic easy-rising zone and the influence of various parameters on the roof falling are obtained.The influence of geology and mining technology on the roof falling are analyzed.Then the concept of complex disaster in deep roadway is proposed and the criterion is obtained.By deriving the roadway considering the residual strength,the critical displacement,critical softening zone depth and critical load of the complex disaster are obtained.The classification of complex disaster can be divided into two types: rock burst dominated roof falling type and roof falling dominated rock burst type.Then the theoretical research on the occurrence of complex disaster is carried out,and the critical displacement,the critical softening zone depth and the critical load formula K of the complex disaster are analyzed,and the influence of the value of K on the complex disaster is obtained.Combined with the destruction phenomenon of complex disaster in mine roadways in Shandong,Xinjiang and Shanxi,the lack of support strength is the main cause of complex disaster.Then it is researched the influence of support on the occurrence of complex disaster,and the K in the critical displacement and the critical softening zone depth formula are analyzed,and the influence of the value of K on the complex disaster is obtained.Combined with the destruction phenomenon of complex disasters in mine roadway in Shandong,Xinjiang and Shanxi,the lack of support strength is the root cause of complex disaster.Finally,the numerical simulation of a mine roadway in Shandong with complex disaster is carried out,and combined with the theory of complex disaster,the effects of excavation speed,support density,top coal thickness and excavation distance on the occurrence of complex disaster are obtained.The paper has 57 figures,9 tables and 67 references.