带压开采工作面长度对底板破坏规律的模拟研究

发布时间：2018-12-21 07:57

【摘要】：近年来，随着上组煤的资源逐步枯竭，部分矿井开始下组煤的延伸，开采时面临着地应力的不断增大、下组煤层受到太原组灰岩含水、奥陶纪灰岩承压水的威胁更加严重的问题，如何有效的预测和防治顶底板的突水问题迫在眉睫。本文主要针对工作面的长度进行了研究，在研究了国内外的研究现状后，依托首旺煤业的工程地质背景，对带压开采情况下底板突水的影响因素、采动支承压力的力学模型、固液耦合两相流的数值模型、等问题进行了研究，并取得了以下的成果：（1）分析了底板的突水原因，即底板含水性、富水性、岩性的组合、地质构造、工程采动和开采条件的共同作用，并且在底板破坏带的深度计算时把影响因子进行了量化，有助于现场对破坏带深度的计算。（2）依据上覆岩层载荷的分布特点，建立了均布载荷和集中载荷的特征力学分析模型，利用弹性力学理论，推导了沿煤层底板岩层内任意一点的应力表达式，为底板的破断位置提供理论计算。（3）根据土力学“位移滑移现场理论”和线性回归计算了底板的破坏带深度h1，，得出在450m埋深时破坏深度在8.5~9.5m；根据“薄板理论”计算了有效隔水带突水的极限水压力，通过反算得出隔水带的厚度h2；主要根据物探的手段去判断导升带的厚度h3。（4）运用数值模拟软件，对带压开采时不耦合和耦合计算时底板的应力分布、最大破坏深度、孔隙水压力进行了对比，得出了考虑耦合条件下底板的破坏深度和应力较大的结论，可能更容易发生突水。（5）根据现场地应力测量，确定了底板的采动破坏深度h1，与数值模拟接近，在此基础上预测不同工作面长度下底板的破坏深度。
[Abstract]:In recent years, with the gradual depletion of the coal resources in the upper group, some mines begin to extend the lower coal, and face increasing in-situ stress during mining. The coal bed of the lower formation is water-bearing by the limestone of Taiyuan formation. Ordovician limestone pressure water threat is more serious problem, how to effectively predict and prevent the roof and floor water inrush problem is urgent. In this paper, the length of the working face is studied. After studying the present research situation at home and abroad, based on the engineering geological background of Shouwang coal industry, the influence factors of water inrush on the floor under the condition of pressure mining, the mechanical model of the mining supporting pressure are analyzed. The numerical model of solid-liquid coupled two-phase flow is studied, and the following results are obtained: (1) the causes of water inrush of the bottom plate are analyzed, that is, the water-bearing, water-rich, lithologic combination, geological structure, and so on. The joint action of engineering mining and mining conditions and the quantification of the influence factors in the calculation of the depth of the floor failure zone are helpful to the calculation of the depth of the damage zone in the field. (2) according to the distribution characteristics of overburden load, the characteristic mechanical analysis model of uniform load and concentrated load is established, and the stress expression of any point along the seam floor is derived by using the theory of elasticity. It provides theoretical calculation for breaking position of bottom plate. (3) according to the "displacement and slip field theory" of soil mechanics and linear regression, the failure zone depth of bottom plate is calculated, and the failure depth is 8.5 ~ 9.5 m at 450 m depth. According to "thin plate theory", the limit water pressure of effective water barrier zone is calculated, and the thickness of water barrier zone h _ 2 is obtained by inverse calculation, and the thickness h _ 3 of conductivity belt is judged mainly by means of geophysical prospecting. (4) by using numerical simulation software, the stress distribution, maximum failure depth and pore water pressure of bottom plate in uncoupled and coupled calculation during mining with pressure are compared. It is concluded that water inrush is more likely to occur when the failure depth and stress of the bottom plate are large considering the coupling condition. (5) according to the in-situ stress measurement, the mining failure depth h _ 1 of the floor is determined, which is close to the numerical simulation. On this basis, the failure depth of the floor under different working face lengths is predicted.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD745

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