深部煤系软岩大巷全断面锚注修复技术研究

Research on full section anchor grouting repair technology for soft rock roadways in deep coal measures

为解决深部煤系软岩大巷变形剧烈、持续时间长且支护困难的问题,以王洼煤矿8煤层南深部集中运输大巷为工程背景,采用现场勘查、矿物组分分析、围岩应力测试、数值模拟分析等方式,揭示了造成深部煤系软岩大巷产生强烈变形的主要原因,得出加强深部煤系软岩大巷支护的控制思路,并在此基础上根据煤系软岩的劣化程度和支护失效特征,提出了基于全断面高强锚索支护+喷浆+全断面注浆锚索锚注支护+钢棚支护的主被动联合补强修复支护方案,并建立了修复支护的“三个阶段、四个步骤”工艺体系。研究结果表明:8煤层南深部集中运输大巷围岩成分复杂、质地软弱、遇水易膨胀崩解,且处于高地应力环境,应力集中系数达到1.46,总体表现出变形速率快、持续时间长、变形量大的特点;原支护设计存在支护强度不足、未针对软岩特性采取有效措施的缺陷,导致顶板、巷帮部分锚杆锚索破断失效;进行全断面锚注修复支护后,形成高强度、范围大、连续性强的预应力场,预应力场有效影响深度增大至原支护的1.5倍。现场试验监测显示:补强修复支护后,大巷巷帮及顶底板变形趋于稳定,表明全断面锚注修复支护工艺对深部煤系软岩大巷的稳定性控制效果显著。

To address the issue of severe deformation,prolonged duration,and difficult support in deep coal measures soft rock tunnels,this paper takes the south deep centralized transportation roadway of No.8 coal seam in Wangwa Coal Mine as the engineering background.Using methods such as field investigation,mineral composition analysis,surrounding rock stress testing,and numerical simulation analysis,the main causes of the intense deformation in soft rock roadways in deep coal measures are summarized and revealed.Based on this,a control strategy for strengthening the support of soft rock roadways in deep coal measures is derived.Furthermore,a active passive joint reinforcement repair support scheme is proposed based on full section high-strength anchor cable support+grouting+full section grouting anchor cable anchor grouting support+steel shed support,considering the deterioration degree of soft rock in deep coal measures and the characteristics of support failure.A“three stages,four steps”technical system for repair support is established.The results show that the surrounding rock of the south centralized transportation tunnel of No.8 coal seam is complex in composition,soft in texture,and prone to expansion and disintegration upon contact with water.It is situated in a high-geostress environment,with a stress concentration coefficient reaching 1.46,exhibiting fast deformation rate,long duration,and large deformation amount.The original support design had deficiencies such as insufficient support strength and lack of effective measures for soft rock characteristics,leading to the failure of some anchor cables in the roof and rib.After implementing full section anchor grouting repair support,a high-strength,wide-range,and continuous prestress field is formed,with the effective influence depth of the prestress field increased to 1.5 times that of the original support.Field test monitoring shows that after the reinforcement repair support,the deformation of the rib and roof and floor plates of roadway tends to stabilize,indicating that the full section grouting repair support technique has a significant effect on controlling the stability of soft rock roadways in deep coal measures.