深部厚煤层巷道失稳破裂演化过程离散元模拟研究

为研究深部厚煤层巷道围岩失稳破裂演化过程,以某煤矿厚煤层巷道为工程背景,采用离散元中随机分布三角形单元块体集合模型研究巷道开挖失稳。对深部厚煤层巷道围岩失稳破裂过程中位移、应力演化规律分析发现:两帮围岩水平应力释放相对于顶底板剧烈,竖向应力反之;围岩竖向应力释放的主要部位是巷道中部。结果表明,深部厚煤层巷道失稳破裂演化的2个主要特征为:1)顶板出现"尖顶型"垮冒,巷中是围岩失稳的关键部位;2)顶底板离层破坏严重。并对其相应机制进行分析:顶底煤岩松散破碎,自稳能力差,顶底板径向应力释放相对剧烈,巷道矩形断面顶、底板受力能力差等因素,导致围岩顶底板离层变形。基于深部厚煤层巷道失稳破裂的演化规律,给出锚索悬吊组合支护方式,结果表明该支护方式可有效地控制厚煤层巷道变形。

Study on instability fracture evolution of deep thick coal seams based on discrete element simulation

To study the instability fracture evolution process of roadway surrounding rock in deep thick coal seam, taking some coal mine as the engineering background, based on the discrete element, this paper has used the random distribution of triangle model unit blocks to analyze the failure process dur-ing roadway excavation process. According to the displacement and stress evolution laws of instability fracture process of surrounding rock in deep thick coal seam, the horizontal stress release has been found to be more intense in two side coal-walls than that in roof and floor of the roadway, while the ver-tical stress is the opposite because the main vertical stress release part is in the middle of the roadway. Numerical simulation results have shown two mains instability fracture evolution characters of sur-rounding rock with thick coal seam roadway. Firstly, there exists "spire" catastrophic collapse in road-way roof, and the middle of roadway is key position of surrounding rock instability. Secondly, roof and floor of the roadway delaminate seriously. The failure mechanisms corresponding with the test results have also been analyzed including factors such as the soft and broken features of roof and floor coal pe-trography, poor stability, the radial stress relatively intense release in roof and floor of roadway, poorbearing capacity in roof and floor of roadway with rectangular cross section, all of which have caused roof and floor of surrounding rock delamination deformation. Based on the failure mechanism of deep buried roadway with thick coal seam, a supporting method consisting of anchor cables has also been given, which can be applied in roadway support, and simulation results have shown that the supporting method can effectively control deformation of thick coal seam roadway.