孤岛工作面柔模混凝土沿空掘巷围岩协同控制技术

Collaborative control technology for surrounding rock of flexible formwork concrete fully gob-side entry driving in island working face

为解决浅埋孤岛工作面无煤柱沿空掘巷围岩强烈变形难题,建立了沿空掘巷覆岩结构模型,分析了沿空掘巷覆岩结构、矿压特征及顶板结构断裂形态,确定了影响完全沿空掘巷围岩稳定性的影响因素。采用理论分析和数值计算方法,确定了支护体可缩量和充填体支护阻力,提出了强化锚固体系承载性能、加强顶帮结构和巷内柔性支护等围岩协同控制思路。研究结果表明:采用新型“三高”锚杆、大直径高预应力锚索及配件进行加强支护,有效控制巷道浅部和深部的变形破坏;要加强巷道帮顶协同控制,通过加强巷帮煤体的支护强度和范围,实现帮部对顶板有效的支撑作用;巷内超前临时支护能抵抗关键覆岩断裂下沉,避免巷道顶板强烈变形;三种支护方式在时空上相互协调,从而实现三种支护方式对沿空巷道的协同控制。现场工程验证表明,巷道围岩和墙体结构保持稳定,变形在可控范围内,巷道支护效果良好。

In order to solve the problem of strong deformation of surrounding rock in fully gob-side entry driving roadway without coal pillar in shallow buried island working face,the overburden structure model of the roadway is established,the overburden structure,ground pressure characteristics and roof structure fracture form of fully gob driving roadway are analyzed,and the influencing factors affecting the stability of surrounding rock of fully gob driving roadway are determined.Using theoretical analysis and numerical calculation methods,the compressibility of the support body,the width of the filling body beside the roadway and the support resistance of the filling body are determined,and the idea of coordinated control of surrounding rock such as strengthening the bearing performance of the anchorage system,strengthening the top wall structure and flexible support in the roadway is put forward.The results show that:firstly,the new“three high”bolt,large-diameter and high prestressed anchor cable and accessories are used to strengthen the support,so as to effectively control the deformation and failure of the shallow and deep parts of the roadway;meanwhile,it is necessary to strengthen the coordinated control of roadway roof,and effectively support the roof by strengthening the support strength and scope of roadway wall coal body;finally,the advance temporary support in the roadway can resist the fracture and subsidence of key overburden and avoid the strong deformation of roadway roof.The three support modes should coordinate with each other in time and space,to collaboratively control the three support modes on the gob-side roadway.The research results have been verified in the field.The surrounding rock and wall structure of the roadway remain stable,the deformation is controllable,and the roadway support effect is favorable.