覆岩分次垮落时留巷顶板离层形成机制

Bed separation mechanism under sequential roof collapse condition in a gob-side entry retaining

从采场侧向覆岩活动的阶段特征入手,结合数值模拟分析了顶板离层的形成过程,建立了顶板岩梁受力模型,推导得出了顶板下沉与离层数值的影响因素和算式.在采动期间,巷道顶板同期破断的岩层组间不会发生离层,分次垮落岩层组间的离层值取决于各岩层组力学性质与层厚的差异,并受顶板岩梁旋转基点深度和采空区侧向悬臂长度的影响.提供合理的顶板支护阻力可以约束锚固区内的离层,以高初撑力锚杆索和单体支柱为基础的刚性主动支护,能够扩散和均化支护应力,满足控顶载荷需求并有效控制离层.

The stages of activity in the lateral strata overlying the goal were studied. Roof sepa- ration initiation and propagation processes were analyzed by numerical simulation. A mechanical model of the rock roof was proposed for beam analysis and the subsequent source terms for subsidence and bed separation were identified. Bed separation between layers is not predicted during mining when fracture failure occurs. Mechanical properties of the strata and difference in layer thickness affect the amount of bed separation between layers during sequential collapse. The rotation point of the roof beam and the lateral cantilever length will also affect this as well. Bed separation may be restrained with appropriate roof supporting force. A rigid, active support from a single hydraulic prop that provides pre-stress can diffuse forces and give a uniform stress. This meets the requirement for roof support and effectively controls bed sepa- ration.