煤层巷道围岩破断失稳演化特征和分区支护研究

发布时间：2018-08-11 11:43

【摘要】：为研究煤层巷道围岩失稳过程及裂隙演化特征,并对支护方式选择提出建议,通过数值模拟获得工作面附近围岩应力分布特征,并将围岩受力状态简化成平面应变问题、准平面应变问题和三维复杂应力问题3种。采用自行研制的相似材料模拟试验台及煤岩体细观力学试验装置,分别针对平面应变和准平面应变2种应力状态下煤岩体的破坏过程及裂隙演化特征进行试验研究。结果表明:1)层状围岩梯形巷道受载失稳存在3个阶段,即楔形破坏阶段、滑移失稳阶段、顶底板大挠度断裂阶段。高垂直应力条件下,顶、底板初始变形造成两帮出现明显剪切滑移后,直接顶、底板分别出现"三铰拱"形态冒落及鼓胀断裂。2)准平面应变条件下,煤体自由端首先出现张拉破裂失稳,造成上覆直接顶砂岩受力不均,并出现一次弯曲断裂;随载荷增大,煤体出现滑移失稳并呈现出"弧线"压出形态,顶板砂岩发生断裂;裂隙煤体与砂岩反复作用形成多对贯通裂隙,说明顶板断裂位置、形态与煤体失稳过程具有显著的对应关系。结合压剪和拉伸破坏机理,对单一煤层巷道和沿空留巷煤层巷道围岩的支护进行分区研究,并提出相应的支护建议。
[Abstract]:In order to study the instability process and fracture evolution characteristics of surrounding rock in coal seam roadway, and put forward some suggestions on the selection of supporting mode, the stress distribution characteristics of surrounding rock near face are obtained by numerical simulation, and the stress state of surrounding rock is simplified to plane strain problem. There are three kinds of quasi-plane strain problems and three dimensional complex stress problems. The fracture process and fracture evolution characteristics of coal and rock mass under plane strain and quasi plane strain were studied by using a similar material simulation test-bed and a meso-mechanical test device developed by ourselves. The results show that there are three stages of load-failure in trapezoidal roadway of layered rock, namely, wedge failure stage, slip instability stage and large deflection fracture stage of roof and bottom slab. Under the condition of high vertical stress, when the initial deformation of the top and bottom leads to obvious shear slip of the two sides, the "three hinged arch" shape caving and bulging fracture (.2) quasi plane strain appear in the direct roof and the bottom plate, respectively. At the free end of the coal body, the tension fracture instability first appears, which causes the overburden direct top sandstone to be unevenly loaded, and a bending fracture occurs; with the increase of the load, the coal body appears slippage instability and presents the shape of "arc line" pressing out, and the roof sandstone is fractured. The repeated interaction between fractured coal and sandstone leads to the formation of multiple pairs of fractures, which indicates that the position and shape of roof fracture have a significant corresponding relationship with the process of coal body instability. Combined with the mechanism of compressive shear and tensile failure, the surrounding rock support of single coal seam roadway and coal seam roadway along goaf is studied, and the corresponding supporting suggestions are put forward.
【作者单位】：河北工程大学矿业与测绘工程学院河北省煤炭矿井建设工程技术研究中心;重庆大学煤矿灾害动力学与控制国家重点实验室;中煤科工集团重庆研究院有限公司;
【基金】：国家自然科学基金项目(51474039,51404046) 河北省教育厅高等学校科学研究计划项目(QN2015069) 邯郸市科学技术研究与发展计划项目(1521109072-7)
【分类号】：TD322.4;TD353

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