高水材料充填沿空留巷应力控制与围岩强化机理及应用

Stress control and surrounding rock strengthening mechanism of gob-side entry retaining with high-water content material filling and its application

高水材料被广泛应用于不同条件下的薄及中厚煤层沿空留巷、部分条件较好的厚煤层沿空留巷,形成了丰富的高水材料充填沿空留巷围岩控制实践。基于高水材料充填沿空留巷理论研究和现场实践,以应力控制与围岩强化为主线,分析了充填留巷围岩在巷道掘进、工作面超前采动影响、留巷围岩调整稳定和邻近工作面复用4个阶段的应力与变形特征,提出了“基本顶二次破断”的覆岩顶板运动特征。以青龙同昌煤矿15102工作面沿空留巷为背景,数值模拟研究了留巷过程中围岩应力和塑性区分布特征,揭示了充填留巷覆岩基本顶的旋转下沉是留巷巷道所受外力的主要来源;在此基础上,提出了充填留巷围岩控制的关键区域,根据高水材料固结体的较强塑性变形特性,提出了高水材料充填沿空留巷围岩分时分区强化机理,确定了合理的高水材料充填体支护阻力计算式、留巷顶板离层计算式和实体煤帮的支护强度计算式,给出了高水材料充填沿空留巷围岩控制关键参数设计方法,关键参数包括充填体支护阻力(充填体宽度和强度)、顶板支护强度(巷内支护和临时支护)、实体煤帮支护强度。介绍了山西高平青龙同昌煤业15号煤层和赵庄煤业9号煤层高水充填沿空留巷围岩控制2个应用实例,留巷围岩变形控制效果良好。最后,提出了高水充填沿空留巷围岩控制技术的发展方向。

High-water content materials were widely used in gob-side entry retaining(GER)in thin and medium-thick coal seams under different conditions and some thick coal seams with good conditions,forming a rich practice of surrounding rock control for GER.Based on the theoretical analysis and field practice of GER filled with high-water content materials,with stress control and surrounding rock strengthening as the main lines,the effects of filling and surrounding rock on roadway excavation,advance mining of the working face,adjustment and stability of the surrounding rock and surrounding rock were analyzed.The stress and deformation characteristics of the four stages were reused in the adjacent working face,and the movement characteristics of the overlying rock roof with“secondary breaking of the basic roof”were proposed.Taking the gob-side entry retaining at the 15102 working face of Qinglong Tongchang Coal Mine as the background,the distribution characteristics of surrounding rock stress and plastic zone in the process of roadway retention were studied by numerical simulations,and it was revealed that the rotation subsidence of overburden main roof of the retained entry was the main source of external force on retained entry combined with numerical simulation.On this basis,the key areas of surrounding rock control of the retained entry were put forward.According to the strong plastic deformation characteristics of the consolidated body of high-water content materials,strengthening mechanism of the surrounding rock by time periods and zones for the retained entry was put forward,reasonable supporting resistance calculation formula of high water material filling body,roof separation calculation formula of roadway retention and supporting strength calculation formula of solid coal seam were determined,and the key parameters calculation of the surrounding rock control for the retained entry filled with high-water content materials was given.The key parameters include the backfill support resistance(backfill width and strength),the strength of the roof support(support in the roadway and temporary support),and support strength of solid coal rib.This paper also introduced two application examples of surrounding rock control of GER filled with high-water content materials in the No.15 coal seam of Tongchang Coal Mine and in the No.9 coal seam in Zhaozhuang Coal Mine of Gaoping City,Shanxi Province.The control effect of surrounding rock deformation of retained entry was good.Finally,the future development of surrounding rock control technology of GER filled with high-water content materials was proposed.