煤矿冲击地压发生风险判别公式及应用

Risk identification formula for coal burst occurrence and its application

针对传统冲击地压发生判别方法缺乏灾害全过程考虑的问题,以煤矿冲击地压发生物理过程分解为切入点,采用理论分析、数值模拟、力学推导、工程验证等方法,开展基于物理过程分解的煤矿冲击地压发生风险判别指数计算公式及其应用研究。结果表明,冲击地压发生物理过程中存在的空间序列为采动围岩极限平衡区—采动围岩近场弹、塑性区—采掘活动空间;依次对应的时间序列为冲击启动阶段—冲击能量传递阶段—冲击地压显现阶段。冲击地压完成物理过程必须同时满足冲击启动和克服阻抗2个力学条件;分别建立了动、静载荷加载型以及高静载荷叠加型冲击地压启动力学模型、冲击地压克服阻抗显现力学模型;得到了冲击地压启动能量判据公式、冲击地压显现能量判据公式;基于上述2项公式建立了既考虑动载荷源、又考虑静载荷源,兼顾冲击启动力学条件满足、冲击地压显现力学条件满足的冲击地压发生风险判别指数计算公式;依据判别指数计算公式,得到冲击地压发生风险性与煤岩体静、动载能之和成正比,与支护及围岩阻抗能成反比的关系;建立了基于冲击地压发生风险判别指数的巷道降载荷−增阻抗耦合防冲工程结构力学模型,并进行了工程应用,实践表明达到了防治冲击地压目的。

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 im-pedance 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.