冲击地压严重威胁煤炭安全高效开采,研究冲击地压发生机制具有重要意义｡首先对矿井回采巷道冲击地压显现特征进行了归纳和总结,认为坚硬顶板和坚硬煤体是回采巷道发生冲击地压的关键地质特征,水平应力是冲击地压力源,巷帮煤体滑脱是回采巷道冲击的破坏特征｡基于弹性地基理论,分析了坚硬顶板条件下回采工作面前方和临空侧顶板向上挠曲､导致煤层竖直压力卸载的特性,并与现场监测工程实践进行对比验证｡在此基础上,以巷帮煤体为研究对象,建立了顶板-煤层-底板复合结构体的卸载滑移力学模型,通过分析煤块所受水平应力､煤体拉力及煤-顶板和煤-底板结构面摩擦力之间的力学平衡关系,建立了巷帮煤体冲击启动的临界方程,并对各变量的取值进行了讨论｡结果显示,开采过程中,悬顶使坚硬顶板向下弯沉,坚硬煤体导致工作面前方和侧方顶板向上挠曲,从而使工作面前方或者侧向煤层垂直压力降低,使得顶底板对煤层夹持作用减弱,巷帮煤体在水平应力作用下,克服顶､底板摩擦力及煤体抗拉力后冲入巷道,形成冲击地压｡基于建立的模型,分析了开采深度､顶板强度､弹模和厚度､煤层强度和弹模等控制要素的影响和作用｡最后,以唐山矿“8·2”冲击地压和红阳三矿“11·11” 冲击地压为例,应用提出的模型解释了坚硬顶板挠曲､巷帮煤体卸载滑脱的冲击地压发生机制,对提出的模型进行了验证｡

Rock burst seriously threatens the safety and economy of coal mining industry. The causality mechanism research of rock burst is of great significance. The occurrence of roadway rock burst accounts for 86.8% of the total rock bursts. Based on the phenomena of rock burst occurred in roadway，this paper considered that hard roof and hard coal are the key geological characteristics of rock burst，and the sliding instability of rib coal mass is their specific failure attribute. Based on the elastic foundation theory，the upward deflection characteristics of the front and lateral roof of the working face under the condition of hard roof are analyzed and compared with the engineering practice of roof rebounding. Taking the roadway coal mass as the object，the unloading sliding mechanical model of roof coal floor composite structure is established. By analyzing the relationship between horizontal stress of coal mass，friction force of coal roof and coal floor and tensile resistance of coal mass，the critical equilibrium equation of rock burst is established. It is proposed that the vertical pressure of coal seam is reduced due to the upward deflection of roof，the underneath coal mass loses its clamping forces and moves into the roadway after overcoming the friction between roof and floor and the tensile strength of coal mass under the action of horizontal stress. This is the unloading and slippage mechanism of rock burst in hard roof mining roadway. The model rationally explains the internal causes of rock burst behavior in hard roof mining roadway. Based on the unloading slippage model，the principles of influencing factors of rock burst，including the depth，roof strength，roof elastic modulus and roof thickness，coal mass strength and elastic modulus are discussed. Finally，two rock burst events，the “8·2” rock burst in Tangshan coal mine and the “11·11” rock burst in Hongyang mine are analyzed and the unloading slippage mechanism is the reason in the two events.

1 冲击地压显现规律

   1.1 冲击地压发生地点

   1.2 冲击地压破坏特征

   1.3 冲击地压发生的条件

2 工作面坚硬顶板挠曲与破断

   2.1 理论分析

   2.2 现场观测

3 回采巷道冲击地压的卸载滑脱机制

   3.1 回采巷道煤层的力学模型

   3.2 基于拜尔利定律的计算

   3.3 煤层滑脱冲击时顶板挠曲量计算

   3.4 冲击地压机理及相关控制因素

4 讨论

   4.1 冲击地压显现位置的原因分析

   4.2 冲击地压破坏形式的原因分析

5 应用实例

   5.1 唐山矿“8·2”冲击地压发生机制

   5.2 红阳三矿“11·11”冲击地压发生机制

6 结论