Experimental Study on Rock Failure Characteristics of Ejective Rock Burst Based on Energy Compensation

Rock burst is a typical type of dynamic geological disaster in the process of underground engineering excavation under high in-situ stress. Based on the understanding of the principle of elastic strain energy accumulation and release in the process of rock burst, the uniaxial load rock burst test is carried out using the self-designed rock burst process experiment system. In addition, the simulation of rock burst with different strength levels is realised. The distribution characteristics of rock burst debris, intensity of rock burst, acoustic emission characteristics, failure mode and energy characteristics of rock burst fracture surface were analysed using statistics and effective kinetic energy theory. According to the test results, the whole process of rock burst is divided into three stages: static incubation stage, dynamic burst stage and comprehensive rock burst development stage. A more severe degree of rock burst indicates larger mass proportion of rock burst fragments, more broken rock burst fragments, farther ejection and throwing distance of fragments and greater effective kinetic energy of fragments. The weaker degree of rock burst indicates smaller mass proportion of rock burst fragments, larger mass of damaged blocks, closer ejection and throwing distance of blocks and smaller effective kinetic energy of fragments. In the load process, many tensile cracks and a certain amount of shear cracks are generated. When more cracks are generated in the load process, the acoustic emission activity becomes more intense. The detritus produced are mostly lumpy, flaky and lamellar.

Automated summary

Rock burst is a dynamic geological disaster that occurs during underground engineering excavation under high in-situ stress. The process of rock burst can be divided into three stages: static incubation, dynamic burst, and comprehensive development. The severity of rock burst is determined by the mass proportion, ejection distance, and effective kinetic energy of rock burst fragments.