深部厚顶煤巷道围岩破坏机理及稳定控制试验研究

The existing problems of deep roadway with thick top coal are that the cracking zone is large, and strength of coal in roof is low, and bed separation takes place easily, and roof accidents happen frequently. The basic reasons for the problems are that the failure mechanism of roadway, which is in the deep complex geological condition, is indefinite, and the control concept and methods have differences. Based on the engineering background of Juye coalfield, typical surrounding rock failure modes of deep roadway with thick top coal are researched, and the corresponding geological models are built. On the basis, three dimensional geomechanical model test system is developed, and failure mechanism of surrounding rock is researched by contrast model test. The mechanical model of roof failure in deep roadway with thick top coal is built, and mechanical criteria of roof failure is obtained by principle of minimum dissipation of energy, and roof failure mechanism is researched. Based on the failure mechanism of surrounding rock and its influencing factors, the surrounding rock control concept and method of deep roadway with thick top coal is proposed, and pressure relief anchor box beam support system is developed, and quantitative evaluating indicator of support system coupling efficiency is built. Surrounding rock controlling effect and mechanical behaviour of support system are analyzed by the contrast of model test and field test, by which the support system is optimized. The research results of local project provide theoretical basis and technical guidance for surrounding rock control problem of deep roadway with thick top coal.

深部厚顶煤巷道围岩的破裂范围大，顶板煤体整体强度低，极易出现离层，顶板事故频发。造成上述问题的根本原因在于深部复杂地质条件下该类巷道的破坏机理不明确，控制理念与方法存在分歧。本项目拟以巨野矿区为工程背景，研究深部厚顶煤巷道围岩典型破坏模式，建立不同失稳破坏模式所对应的地质模型。在此基础上，研发大型三维地质力学模型试验系统，通过地质模型对比试验，研究围岩失稳破坏机理。同时，建立深部厚顶煤巷道顶板失稳破坏的理论分析力学模型，运用能量耗散最小原理，得出顶板失稳的力学判据，研究顶板围岩破坏机制。基于围岩失稳破坏机理及关键影响因素，提出深部厚顶煤巷道围岩控制理念，改进自主研发的让压型锚索箱梁支护系统，建立支护系统耦合性能定量评价指标，并通过模型试验与现场对比试验，完善深部厚顶煤巷道失稳破坏理论，优化支护系统。本项目研究成果将为解决深部厚顶煤巷道的围岩控制难题提供理论依据与技术指导。

本项目以巨野矿区典型的深井煤矿-赵楼煤矿为工程背景，针对深部高地应力作用下厚顶煤巷道支护难题，通过现场实测、理论分析、材料研发、数值分析、模型试验及现场试验等手段相结合的方法，对深部厚顶煤巷道的变形破坏及围岩控制机理进行研究。.项目主要对通过深部厚顶煤巷道变形破坏规律现场实测研究，得到了赵楼煤矿深部厚顶煤巷道顶板围岩不可控的主要原因及机制。基于塑性力学的极限分析理论，采用广义Hoek-Brown经验强度准则，推导出了巷道顶板冒落的迹线方程，讨论了不同岩体力学参数、围岩应力水平与支护荷载大小对顶板冒落范围的影响。提出了深部厚顶煤巷道“先控后让再抗”的耦合让压强力支护理念，改进了自主研发的让压型锚索箱梁支护系统。研制了新型柔性均布压力加载装置，基于赵楼煤矿3302工作面顺槽地质条件，针对让压型锚索箱梁支护系统两种典型支护方案（纵梁支护方案和横梁支护方案）下的开挖支护过程进行了地质力学模型试验研究，得到了不同支护方案的巷道围岩应力演化规律、围岩变形规律及支护构件的受力特性。建立了锚索梁支护系统对顶板围岩作用的三维力学模型，对锚索梁支护系统不同布置方式作用下的顶板围岩应力状态进行了分析，结果显示：纵横组合方案在顶板围岩中形成的围压状态最佳，其次为纵向单梁方案。在典型工程赵楼煤矿设计并实施了让压型锚索箱梁支护系统、工字钢锚索梁支护系统及T型钢带锚索梁支护系统、U型钢带锚索梁支护系统4大类14种数值试验和3大类11种方案的现场试验。研究表明：让压型锚索箱梁支护系统各方案比原支护方案效果显著提高；让压型锚索箱梁支护系统围岩控制效果整体优于工字钢锚索梁支护系统且经济性高；让压型锚索箱梁4种支护方案中，巷道围岩控制效果最好的为纵横组合方案，其次为纵向单梁方案，再次为纵向双梁方案，最后为横梁方案。.通过理论计算、数值试验与现场试验结果综合分析，最终得到了深部厚顶煤巷道围岩变形破坏机理及让压型锚索箱梁控制机制。