沿空巷道服务周期长,矿压显现强烈,一次采动后往往造成巷内围岩大变形,难以为下区段工作面开采继续服务。以丁集煤矿1452(1)工作面一次采动结束后留巷修复治理和重新加强支护为工程背景,现场测试留巷断面收缩程度,将其划分为3个不同变形特征的待修复治理区域。理论分析巷内围岩变形机理:切顶高度内的顶板破断、回转及采空区垮落矸石的反复压实造成了顶板的非对称变形;采动引起的高支承压力对煤帮破碎区挤压是造成巷帮变形的主要原因;上覆岩层载荷以实体煤帮和采空区矸石帮为媒介传递到底板引起巷道底板变形破坏。利用极小势能原理得到底鼓随应力集中程度的增加而线性增大的结论,并结合数值模拟分析一次采动后顶底板的最小主应力分布状况,以此反映顶底板的应力集中程度。确定留巷修复治理的最佳时机与修复工艺,基于对留巷围岩变形的分析,提出“围岩结构分级分区主被动协同支护”技术。现场监测结果表明,下区段工作面回采时,巷内围岩变形及恒阻锚索受力稳定,该控制技术能够有效控制巷道围岩变形,所留巷道能够满足复用要求。

The service cycle of gob-side entry retaining is extended, characterized by intense mine pres- sure that often leads to significant deformation of the surrounding rocks in the entry post-mining. This de- formation poses challenges for supporting the mining activities of the lower section working face. Based upon the engineering background of the 1452(1) working face of Dingji Coal Mine for the repair and control of gob-side entry retaining after the first mining operation and re-reinforced support, the shrinkage degree of the entry section was tested on-site and divided into three areas to be repaired with different deformation characteristics. Through theoretical analysis, the deformation mechanism of sur-rounding rocks in entry was analyzed, which was founded that the asymmetric roof deformation was caused by roof breaking, rotation, and repeated compaction of collapsed gangue in the goaf area within the roof-cutting height. Deformation on the coal side was primarily due to high support pressure from mining activities. The load of overlying rocks was transmitted to floor through the solid coal side and the gangue side in the goaf area, resulting in deformation and damage to the floor of the roadway. Based on the principle of minimum potential energy, heaving floor was found to increase linearly with stress con- centration increasing. The minimum main stress distribution of roof and floor was analyzed with numeri- cal simulation after a mining operation to reflect the stress concentration of roof and floor. Optimal time and repair process were determined for repairing entry. The deformation of surrounding rocks in entry was analyzed to propose collaborative support for the hierarchical zoning of the surrounding rock struc- ture. The on-site monitoring results showed that the deformation of the surrounding rocks in entry and the force of the constant-resistance anchor cable were stable when the working face of the lower section was mined. The control technology can control the deformation of the surrounding rocks of the roadway, and allow for the reuse of entry retaining