大断面强采动综放煤巷顶板非对称破坏机制与控制对策

 针对大断面强采动综放煤巷开掘过程中出现的顶板非对称变形破坏现象，以王家岭煤矿为工程背景，通过现场调研、室内试验、理论分析、数值模拟和井下试验等手段，对变形破坏机制与控制对策进行研究。得出如下结论：(1) 综放煤巷顶板呈现非对称变形破坏特征，表现为煤柱侧顶板严重下沉、剧烈水平滑移变形及肩角部位顶板错位、嵌入、台阶下沉等；(2) 侧向基本顶于煤柱上方距采空区边缘6～7 m处发生破断，基本顶的破断和回转下沉运动引起的不均衡支承压力q和回转变形压力?是沿空巷道不对称变形破坏的根本力源，靠煤柱侧顶板及肩角部位是巷道变形破坏的关键部位；(3) 受采空区不稳定覆岩运动和巷道开挖影响，巷道围岩结构和应力分布以巷道中心线为轴呈非对称性分布，而原有支护未能对煤柱侧顶板及肩角等部位加强支护且无法适应顶板剧烈水平运动，巷道掘出后呈现出非对称矿压显现，后期受到本工作面回采影响，非对称变形破坏进一步加剧。(4) 分析该类巷道支护原理，提出集高强锚梁网、非对称锚梁桁架结构、预应力锚索桁架的非对称控制体系，阐述其控制机制，并进行方案设计和工程应用。数值模拟和工程实践表明，该技术可有效减弱顶板应力和位移分布的非对称性，控制围岩非对称变形破坏。

Asymmetric failure and control measures of large cross-section entry roof with strong mining disturbance and fully-mechanized caving mining

Asymmetric deformation failure during the process of excavating and supporting of large cross-section entry roof with strong mining disturbance and fully-mechanized caving mining at Wangjialing coal mine was studied systematically through field investigation，laboratory test，analytical analysis，numerical simulation and in-sit test. The mechanism of deformation failure and the controlling measures were investigated. The roof of gob-side entry was found to display the asymmetric deformation failure characteristics，which included sever subsidence of roof near the pillar sides，radical horizontal dislocation deformation and dislocation，embedding，step convergence at the roof-wall corner，et al. The lateral main roof broke at a distance of 6–7 m away from the gob-edge above the pillar. Unbalanced side abutment q and rotary deformation pressure ? induced by the broken and rotation of main roof are the fundamental cause causing the asymmetric deformation failure characteristics. The deformation failure was significantly influenced by a key position of roof near the pillar side and roof-wall corner surrounding rocks. Due to the movement of the unstable overlying strata and the entry excavation，the surrounding rock structure and stress distribution were asymmetric evidently on the axis of roadway，but the original supporting systems did not provide the reinforced support to key position and adjust to the strongly horizontal dislocation，which resulted in the asymmetric strata behaviors shortly after the development of entry. The asymmetric failure tended to be more severe later affected by the extraction of the present panel. The control principle of the entry was analyzed and an asymmetric supporting system was proposed composed of cable- beam-net，asymmetric cable-beam and cable-truss. And the support scheme was put into field application. The numerical simulations and engineering applications demonstrated that the support weakened the asymmetric of stress and displacement of the roof and controlled the asymmetric deformation failure.