增量荷载作用下深部煤巷冲击破坏规律模拟试验研究

Impact failure law of deep coal roadway under incremental load based on similar simulation test

为研究深部煤巷道围岩应力状态与围岩结构冲击破坏之间的关系,探索深部煤巷冲击地压发生机制,利用设计的可水平和垂直双向增量加载相似模拟试验平台,试验分析了巷道围岩全过程(自掘进至成巷)应力演化及宏观破坏特征,研究了增量荷载作用深部煤巷围岩冲击破坏规律。研究得到:(1)掘进成巷时,巷道围岩体为应力卸荷状态;成巷后,巷道围岩应力开始进入"缓增—快增—缓增"波动阶段;当巷道模型左侧和顶部载荷增加时,围岩变形增大、局部破坏明显,巷道围岩应力开始进入"快增—突变"阶段,巷道发生冲击破坏;冲击破坏后,巷道围岩应力进入"降低—稳定"阶段,与载荷增加前的围岩应力大小相比,顶底板岩层、左帮、右帮浅部等煤体应力基本恢复到冲击破坏前的大小,但巷道右帮煤体深部应力仍处于较高应力状态。(2)深部煤巷围岩冲击破坏与其应力状态呈正相关关系,静载作用下围岩应力呈波动缓增状态,围岩结构破坏不明显;增量荷载作用下,巷道围岩应力呈快增突变状态,局部围岩破坏明显、冲击破坏发生,围岩应力经历了从初始增加到波动增加、再到突变及平衡共7个演化阶段,试验再现了围岩冲击破坏发生的全过程,揭示了冲击破坏发生时的围岩应力突变特征。(3)在山东滕东煤矿3_(下)113综放工作面开展了工程实践研究,现场实测表明,试验结果基本符合现场实际,验证了本文试验方法及结果的可靠性。基于试验结果,提出优化调整巷道围岩应力时空变化和提高围岩整体性的围岩卸压与补强支护技术方案,为深部煤巷冲击地压防治提供了重要依据。

According to the conditions of deep high pressure coal roadway, a two-way incremental load similarity simulation test platform was designed and developed, and a similar model of coal roadway of deep mine was established, the incremental load simulation test was performed on the strata failure process of coal roadway(from excavation to formation of roadway).Also, the disaster mechanism of rockburst of coal roadway was discussed.The results show that(1) when the roadway is formed, the surrounding rock mass is in the state of stress unloading.After the roadway is formed, the surrounding rock pressure of the roadway begins to enter the fluctuating stage of "slow increase-fast increase-slow increase".When the load on the left and top of the roadway model increases, the deformation of surrounding rock increases and the local damage is obvious.The pressure of surrounding rock begins to enter the "quick-increase-mutation" stage, and the roadway rockburst occurs.After the impact failure, the surrounding rock pressure of the roadway enters the "reduced-stable" stage.Compared with the pressure of the surrounding rock before load increase, the pressure of roof and floor strata, the left side and the shallow part of the roadway right side basically returns to the size before rockburst, but the deep pressure of the right side of the roadway is still in a high stress state.(2) During the excavation, the strata of coal roadway enter the unloading state, and the pressure is in a state of gradual fluctuation and no sudden change.After the excavation, the unloading strata of the coal roadway is further damaged, and the pressure enters a "fast increase-slow increase" fluctuation stage, and the mutation is not obvious.By applying incremental load on both sides of the model, the damage of surrounding rock is more obvious, and the pressure enters the "rapid increase-sudden change-calm" stage.It is characterized by "rapid increase first and mutation later". When the incremental load is applied to the test model, the strata failure of coal roadway is characterized by increased local deformation, obvious failure deformation fluctuations, and surrounding rock instability impact in deep mine.(3) The engineering practice research has been carried out in the 3113 fully mechanized top-coal caving mining work face of Tengdong Coal Mine in Shandong Province.Field measurement shows that the test results are basically in line with the actual situation, which verifies the reliability of the test method and results in this study.According to the spatial structure model of strata of the deep roadway, it can be known that the development and adjustment of the surrounding rock structure and stress is actually an impact instability process from rock deformation, structure incubation to impact instability of the interaction of the roof structure, the roadway wedge wall structure and the floor swell structure under incremental load.The research shows that the simulation test better reveals the mechanics of impact disaster of rock burst in deep roadway.