二次沿空留巷覆岩移动破坏规律及巷旁支护参数研究

发布时间：2018-03-30 18:13

本文选题：二次沿空留巷　切入点：巷旁支护　出处：《重庆大学》2015年硕士论文

【摘要】：传统的一次沿空留巷是在上区段工作面开采后,通过加强支护等方法,将原机巷保留下来,作为下区段工作面回风巷,即“一巷两用”。本文研究的二次沿空留巷是在一次沿空留巷的基础上,待下区段工作面开采后继续保留,作为采空区瓦斯抽采巷。采用理论分析、相似材料模拟、数值模拟等方法,对薄煤层二次沿空留巷巷旁支护技术进行了研究,主要成果如下:①通过MTS815型液压伺服系统对煤岩进行常规三轴压缩试验,获得了煤岩的基本物理力学性质;采用岛津试验机对煤岩进行了单轴压缩试验,同时对破坏过程中,煤岩声发射特征进行监测,获得了煤岩应力—应变曲线和声发射的关系。②根据相似材料及数值模拟试验,对采场围岩的应力、位移演化规律进行了研究。结果表明:1)大龙煤层二次沿空留巷后,两侧支护体均形成应力集中,其高帮应力峰值达53.92MPa,导致巷道变形急剧增加,维护困难;2)受上部大龙煤层的开采影响,围岩应力整体有所下降,羊子炭煤层二次沿空留巷后的应力峰值为37.92MPa,较大龙煤层下降了29.67%,为巷旁支护创造了有利条件。③通过理论分析,建立二次沿空留巷巷旁支护阻力力学模型,得到了巷旁支护阻力计算公式,并根据试验巷道工程地质条件,获得了二次留巷阶段两侧巷旁支护阻力与支护宽度的关系;在基本顶给定变形下,建立了二次沿空留巷顶板下沉量预计力学模型,通过位移变分原理及能量守恒,得出了二次沿空留巷顶板下沉量计算公式。④采用数值仿真方法,研究了不同巷旁支护参数对一次沿空留巷和二次沿空留巷附近的围岩应力及位移演化规律。结果表明:1)低强度支护体给巷道带来较小的应力分布,巷道承受的应力较小,但支护体本身承载性能低,易造成二次留巷变形较大,同理,高强度支护体引起了围岩整体应力升高,但巷道围岩变形减少;2)宽高比对围岩应力具有较明显的影响,小宽高比由于支护体本身失稳,造成围岩应力低,变形严重,宽高比大的支护体引起围岩应力增高,变形随之减少。因此,合理的支护宽高比和强度对维持巷道的稳定性有重要的作用。
[Abstract]:After mining in the upper section face, the traditional primary gob-side roadway is reserved by strengthening the support and so on, as the return air roadway of the lower section working face, That is, "one roadway dual use". The secondary gob-side retaining roadway studied in this paper is based on the primary gob-side retaining roadway, which will continue to be retained after mining in the next section face, as a gas drainage roadway in the goaf. Theoretical analysis and similar material simulation are used. Numerical simulation and other methods are used to study the supporting technology of secondary gob-side roadway in thin coal seam. The main results are as follows: 1. The basic physical and mechanical properties of coal and rock are obtained by routine triaxial compression test of coal and rock by MTS815 hydraulic servo system. Uniaxial compression test of coal and rock was carried out by using Shimadzu testing machine, and the characteristics of acoustic emission of coal and rock were monitored during the process of destruction. The relationship between stress-strain curve and acoustic emission of coal and rock was obtained according to similar materials and numerical simulation tests. The stress and displacement evolution of surrounding rock of stope is studied. The results show that after the second gob retaining roadway in Dalong coal seam, the stress concentration is formed on both sides of supporting body, and the peak value of high side stress is up to 53.92 MPa, which results in a sharp increase of roadway deformation. The stress of surrounding rock of Yangzi coal seam is decreased, the peak stress of Yangzi coal seam is 37.92MPa, and the larger coal seam is 29.677.Three favorable conditions are created for roadway side support by theoretical analysis, the stress of surrounding rock is decreased by the mining of the upper Dalong coal seam, and the peak value of stress is 37.92MPa after the secondary goaf in Yangzi coal seam. The mechanical model of side support resistance of secondary gob retaining roadway is established, and the formula of roadside support resistance is obtained. According to the engineering geological conditions of test roadway, the relation between side support resistance and supporting width is obtained in the stage of secondary retaining roadway. Under the given deformation of the basic roof, the prediction mechanical model of the roof subsidence of the secondary gob retaining roadway is established. By means of the displacement variational principle and energy conservation, the calculation formula of the secondary gob-side roadway roof subsidence is obtained by using the numerical simulation method. The evolution law of surrounding rock stress and displacement in the vicinity of primary and secondary goaf retaining roadways with different roadway side support parameters is studied. The results show that the low strength support brings smaller stress distribution to the roadway, and the stress of the roadway is smaller than that of the second gob retaining roadway. But the bearing capacity of the supporting body itself is low, and it is easy to cause large deformation of secondary retaining roadway. In the same way, the high strength support body causes the whole stress of surrounding rock to increase, but the ratio of width to height of roadway wall rock deformation decreases by 2) the ratio of width to height has obvious influence on the stress of surrounding rock. Due to the instability of the supporting body itself, the small aspect ratio causes the surrounding rock stress to be low, the deformation is serious, and the wall rock stress increases and the deformation decreases when the width to height ratio is large. Reasonable ratio of width to height and strength play an important role in maintaining the stability of roadway.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD353

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