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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σ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。
Aiming at the unsymmetrical deformation and failure of the roof during the digging process of the large section and fully mechanized top coal caving mining roadway, taking the Wangjialing coal mine as the engineering background, through field investigation, laboratory test, theoretical analysis, numerical simulation and downhole test, Destruction mechanism and control strategy. The conclusions are as follows: (1) The roof of the fully mechanized top coal caving shows asymmetric deformation and failure characteristics, which are as follows: serious collapse of roof of coal pillar, drastic horizontal slip deformation and dislocation of top plate at shoulder corner, embedding, 2) Laterally almost at the top of the coal pillar breaks away from the edge of the goaf 6 ~ 7 m, the unbalanced support pressure q and the swivel deformation pressure σ caused by the rupture of the basic roof and the swivel sinking motion are the asymmetry along the gob-side entry Deformation and destruction of the fundamental source of force, by coal pillar side roof and shoulder corners of the key part of the deformation and destruction of the roadway; (3) by the goaf instability overburden movement and roadway excavation, tunnel surrounding rock structure and stress distribution The central axis of the roadway is asymmetric distribution of the axis, while the original support fails to strengthen the support to the roof and shoulder corners of the coal pillar and can not adapt to the drastic horizontal movement of the roof. After excavation of the roadway, the asymmetric rock pressure appears , Later by the face of the impact of mining, asymmetric deformation and destruction further intensified. (4) Analyze the principle of roadway support, put forward the asymmetric control system of high strength anchor beam network, asymmetric anchor beam truss structure and prestressed anchor cable trusses, explain its control mechanism, and carry out program design and engineering application. Numerical simulation and engineering practice show that this technique can effectively reduce the asymmetry of roof stress and displacement distribution and control the asymmetric deformation and failure of surrounding rock.