深部薄煤层双侧沿空留巷支护技术及巷旁支护材料研究

发布时间：2018-12-05 21:20

【摘要】：随着浅部资源的逐渐减少和枯竭,地下开采由浅到深已经成为必然趋势。但是,随着开采深度的增加,将面临地质环境趋于复杂、高瓦斯压力、高地应力、高温以及软岩控制等一系列技术难题等。在复杂生产环境下,传统的“U”型通风方式易造成工作面上隅角瓦斯积聚和超限问题,严重制约着矿井的高效、安全生产,很大程度上限制了深部开采的规模和速度。通过沿空留巷技术,实现采煤工作面“Y”型通风可有效解决上述瓦斯积聚和超限问题。目前据大多数矿井使用单侧的沿空留巷方案,即在巷道一侧留设支护体。如果在巷道两侧留设支护体,即双侧采空沿空留巷,两侧的工作面推进后,巷道可作为瓦斯抽采巷继续使用,将实现更大的经济价值。然而,目前针对深部薄煤层开采双侧采空沿空留巷技术尚不成熟,其应力复杂状态、围岩破坏特征、稳定性控制等是沿空留巷采矿亟待研究的问题。采用自行研制的可旋转平面应力试验台进行相似材料模拟试验,研究了两次采动影响下双侧采空沿空留巷上覆岩层运动规律、破断特征和支承压力分布特征;基于二次沿空留巷力学作用原理,提出了深部薄煤层双侧采空沿空留巷力学模型;然后,通过分析沿空留巷基本顶关键块B的受力情况、上覆岩层运动规律和沿空留巷稳定性控制因素,对煤矿巷内支护和巷旁支护进行了优化设计。由于巷内支护技术相对成熟,本文着重研究了巷旁支护材料选型及其在受载下的变形破坏规律,为巷旁支护现场试验材料的选择提供了可靠依据。主要获得如下研究结论:①通过相似材料模拟试验,获得了多次采动薄煤层开采条件下上覆岩层移动规律。与中厚煤层开采后的顶板变形及破断规律不同,薄煤层采空区直接顶垮落后能够充满采空区,使得上覆岩层的运动没有足够的空间。据此得到的岩层破断角以及最大离层高度等上覆岩层移动规律对薄煤层沿空留巷围岩控制、巷内和巷旁支护参数的选择具有重要的参考价值。②基本顶关键块的结构状态对沿空留巷的稳定性控制有着极其重要的影响,是确定该类开采条件下影响留巷稳定性的主要因素,由理论分析得知,不同阶段采动对关键块稳定性影响具有差异性。③通过分析现有沿空留巷巷内支护和巷旁支护的缺陷及其不足的原因,提出了具有刚度耦合、协同变形、可共同承担上覆岩层荷载等优点的巷旁支护和巷内支护技术。④对巷旁支护材料变形特征及力学响应的研究表明,“矸石袋+锚网”支护系统在前期具有一定的回缩量,能起到让压作用;随着矸石体进一步压缩,在后期能够提供较大的支撑力,满足深部薄煤层沿空留巷巷旁支护在材料变形和强度方面的要求。
[Abstract]:With the gradual reduction and depletion of shallow resources, underground mining from shallow to deep has become an inevitable trend. However, with the increase of mining depth, it will face a series of technical problems such as complex geological environment, high gas pressure, high ground stress, high temperature and soft rock control and so on. In the complex production environment, the traditional "U" ventilation method can easily cause gas accumulation and over-limit in the upper corner of the working face, which seriously restricts the high efficiency and safety production of the mine, and to a great extent limits the scale and speed of deep mining. Through the technology of retaining roadway along the gob, the problem of gas accumulation and over-limit can be effectively solved by realizing "Y" type ventilation in coal mining face. At present, most coal mines use one side along the roadway, that is, retaining the supporting body on the side of the roadway. If the supporting body is set up on both sides of the roadway, that is, the double-side goaf is left along the gob, the roadway can continue to be used as the gas drainage roadway after the face of both sides is pushed forward, which will realize greater economic value. However, in view of deep thin coal seam mining technology along the gob is not mature, its stress complex state, surrounding rock failure characteristics, stability control and so on are urgent problems to be studied. The similar material simulation test was carried out by using the self-developed rotating plane stress test rig. The movement law of overlying strata, fracture characteristics and supporting pressure distribution characteristics of the double side goaf along the goaf were studied under the influence of twice mining. Based on the mechanics principle of secondary gob retaining roadway, a mechanical model of deep thin coal seam with double goaf side gob retaining roadway is put forward. Then, through the analysis of the stress on the key block B of the basic roof along the gob, the movement law of the overlying rock and the controlling factors of the stability of the roadway along the gob, the optimum design of the support in the roadway and the support beside the roadway is carried out. Due to the relatively mature supporting technology in roadway, this paper mainly studies the selection of supporting materials and its deformation and failure law under load, which provides a reliable basis for the selection of field test materials for roadway side support. The main conclusions are as follows: 1 through the simulation test of similar materials, the overlying strata movement law under the condition of multiple mining thin coal seam is obtained. Different from the roof deformation and breaking law after mining in medium and thick coal seam, the direct roof collapse of the goaf in thin coal seam can be filled with goaf, so that there is not enough space for the movement of overlying strata. The overlying strata movement rules, such as breaking angle and maximum height of the separated strata, can control the surrounding rock around the roadway along the goaf of the thin coal seam. The selection of supporting parameters in and around the roadway has important reference value. 2 the structural state of the key block of the basic roof has an extremely important influence on the stability control of the roadway along the gob. Is the main factor to determine the stability of retaining roadway under this mining condition. The influence of mining at different stages on the stability of key blocks is different. (3) by analyzing the defects of existing roadway support and roadway side support along the goaf and the reasons for their shortcomings, the stiffness coupling and cooperative deformation are put forward. The research on deformation characteristics and mechanical response of roadway side support material shows that the support system of "gangue bag bolting net" has a certain amount of retraction in the early stage. Can play the role of pressure; With the further compression of gangue, a large supporting force can be provided in the later stage, which can meet the requirements of material deformation and strength in the side support and protection of roadway along goaf in deep thin coal seam.
【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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