Mechanism And Application On Rock Burst Protected And Controlled By Composite Weak Structure

Rock burst is one of the most serious dynamic disasters during the process of deep mining.The prevention and control technology of rock burst play an important role in moden mining safety.This paper is based on physical and mechanical properties of composite weak structure and makes use of theoretical calculation,laboratory test,numerical simulation and field practice.At the same time,the protect and control technology of rock burst by composite weak structure is fully studied,according to the analysis of deformation characteristics,stress condition and energy evolution law.According to the different proportions of soft and hard stratum,the composite degree is put forward.The deformation and failure characteristics and mechanical behavior of the different combination forms of composite weak structure are studied.The differently composite degree changes the creep and unloading.The hard stratum mainly controls the short-time strain.The soft stratum mainly adjusts the time of strain.Under the extermal influence,the strength and thickness of soft and hard stratum are the direct factors for stress condition of overall structure.The control mechanism of elastic energy index and impat energy index by composite weak structure shows the composite weak structure play an important role in the absorption and dissipation of impact energy.This paper reveals that the composite degree is in propotion to transfer and dissipation of impact energy.The theoretical basis on the controllability of rock burst by composite weak structure is put forward.From the perspectives of energy releasing and dissipation,the main factors,by which the composite weak structure can control impact energy,are strength index,soft media,location and structure size.Through the numerical simulation,the relationship between the near and far field and roadway and the evolution laws of impact energy by different size are studied.This paper reveals that the enegy accumulation degree around the roadway is in proportion to the distance between roadway and composite weak structure and in inverse proportion to the size of composite weak structure.Through the evolution laws of impact energy by composite weak structure,the failure mode and impact behaviors of different coal and rock mass are explained.From the difference of composite degree,the rock burst formd by the roadway and different roof and floor is elaborated.Base on the energy of rock burst protected and controlled by composite weak structure,the control model of impact energy is established.The theories of classified protect and control and application are analyzed.The spatial and temporal mechanism and dynamic improvement are raised.The technology systm of controllability is formed in the end.Combining the mechanism of rock burst protected and controlled by composite weak structure,the engineering application is carried out in Tangshan coal mine,which verifies the protect and control effect by composite weak structure and make great contribution to high energy impact disasters.