Risk identification formula for coal burst occurrence and its application

Abstract

Aiming at the problem that the traditional discrimination method of rock burst generation lacks the consideration of the whole disaster process and has some defects, taking the decomposition of the physical process of coal mine rock burst generation as the starting point, the calculation formula and application of the discrimination index of coal mine rock burst generation based on the decomposition of physical process are investigated by using the methods of theoretical analysis, numerical simulation, mechanical derivation and engineering verification. The results show that the spatial sequence in the physical process of rock burst is the limit equilibrium zone of mining surrounding rock-near-field elastic and plastic zone of mining surrounding rock-mining activity space. The corresponding time series are burst initiation stage, burst energy transmission stage and burst ground pressure manifestation stage. To complete the whole physical process of rock burst, two mechanical conditions must be met at the same time: impact start-up and overcoming impedance. The dynamic and static load type and high static load superposition type rock burst start-up mechanical models and rock burst impedance overcoming mechanical models are established respectively. The starting energy criterion formula of rock burst and the apparent energy criterion formula of rock burst are obtained. Based on the above two formulas, the calculation formula of rock burst occurrence discrimination index has been derived considering both dynamic load sources and static load sources, and taking into account that the mechanical conditions of rock burst initiation and rock burst appearance are satisfied. According to the discriminant index formula, it is obtained that the possibility of rock burst is directly proportional to the sum of static and dynamic loads of coal and rock mass, and inversely proportional to the impedance energy of support and surrounding rock. The structural mechanics model of roadway load-reduction impedance-increase coupling anti-burst engineering based on the occurrence discrimination index of rock burst is established and applied in engineering. The practice shows that the purpose of preventing rock burst is achieved.

Keywords

• coal burst
• all process
• risk
• discriminant index
• increasing impedance
• energy criterion