采动影响下覆岩应变—孔隙率—渗透率演化模型开发及应用

发布时间：2018-07-10 05:17

本文选题：岩层移动模型 + 地表沉陷观测　；参考：《中国矿业大学》2017年硕士论文

【摘要】：采场覆岩会随着工作面的推进发生移动、变形和破断等运动,纵向上形成“竖三带”,不同区域内的岩层受扰动后的渗透率变化也不同。因此,采动覆岩渗透率分布的研究对掌握瓦斯在采动覆岩中的运移规律进而提高井下抽采瓦斯效率均有重要意义。本文首先引入应用于地表沉陷计算的影响函数法,推广建立了分区情况下的工作面上覆岩层移动模型,对关键参数选取进行讨论并合理地优化。为了验证移动模型的可靠性,通过在工作面上方地表设立地表沉陷观测站以及利用数值模拟方法对其地表的观测结果、覆岩层运动的模拟结果与模型的理论计算结果进行了双向对比验证。基于前述覆岩层移动计算模型,进一步开发了描述采动岩层应变-孔隙率-渗透率之间的模型。通过分析覆岩移动、垮落规律,在纵向上按覆岩发育“竖三带”分别发展了岩层渗透率计算方法,主要取得以下成果:(1)开发了基于影响函数法的岩层移动模型,依据“竖三带”分区建立不同区域内岩层的移动模型,并对其中涉及到的关键参数进行讨论与优化。(2)基于“竖三带”不同区域内采空区上覆岩层的移动特性,分别建立了岩层应变-孔隙率-渗透率模型,可对冒落带岩层(孔隙发育为主)、裂隙带以及弯曲下沉带岩层(裂隙发育为主)的渗透率分别进行计算。(3)以阳煤五矿8133工作面为工程背景,将上述模型的理论结果分别与地表沉陷观测和3DEC数值模拟进行了对比,结果表明所建立的岩层移动数值模型的计算结果和实测吻合程度较高;同时,模拟结果表明垮落带最终发育高度为57.3m,岩层移动模型计算结果则为55.87m,二者之间的偏差较小。(4)利用开发的岩层应变-孔隙率-渗透率模型对阳煤五矿8133工作面覆岩进行了渗透率分布变化的计算,计算结果表明:采空区上方55.87m附近的岩层受采动影响,裂隙较发育,渗透率变化大。结合矿方瓦斯治理的需求,提出了高抽巷层位高度设计的优化方案,在实际工程效果中对工作面瓦斯抽采效果良好,其中高抽巷的瓦斯抽采量占到了工作面瓦斯总抽采量的96.76%以上。本文建立了一套分区计算岩层移动模型,以及相应的岩层应变-孔隙率-渗透率模型,利用现场观测、模拟分析验证模型可靠性,也取得了一定的工程效果。结果证明,理论计算结果具有良好的可靠性及实用性。通过本文的研究,针对采动覆岩建立的岩层移动模型以及应变-孔隙率-渗透率计算模型不但有利于井下瓦斯抽采,而且可以进一步推广应用于治理地层水涌出、设计地表保水开采方案等。
[Abstract]:The overburden rock of stope will move, deform and break with the advance of the working face, and form vertical "vertical three zones", and the permeability changes of rock strata in different areas are also different after disturbance. Therefore, the study of permeability distribution of mining overburden rock is of great significance for mastering the migration law of gas in mining overburden rock and improving the efficiency of underground gas extraction. In this paper, the influence function method which is applied to the calculation of surface subsidence is introduced, and the model of overlying strata movement is established in the case of subdivision. The selection of key parameters is discussed and optimized reasonably. In order to verify the reliability of the moving model, the surface subsidence observation station is set up above the working face and the observation results of the surface are obtained by using numerical simulation method. The simulation results of overlying strata are compared with the theoretical results of the model. Based on the above calculation model of overlying strata movement, a model describing the strain-porosity permeability of mining strata is developed. Based on the analysis of overburden movement and collapse law, the calculation method of strata permeability is developed according to the vertical three zones of overburden rock in longitudinal direction. The main achievements are as follows: (1) the model of strata movement based on influence function method is developed. According to the division of "vertical three zones", the movement model of strata in different regions is established, and the key parameters involved in it are discussed and optimized. (2) based on the characteristics of the movement of overlying strata in different goaf areas in "vertical three zones", Strain, porosity and permeability models are established respectively. The permeability of rock strata in caving zone (mainly pore development), fracture zone and bending subsidence zone (mainly crack development) can be calculated separately. (3) the engineering background is 8133 face of Yang-coal No. 5 Mine. The theoretical results of the above models are compared with the surface subsidence observation and the 3DEC numerical simulation, respectively. The results show that the calculated results of the established numerical model are in good agreement with the measured ones, and at the same time, The simulation results show that the final development height of caving zone is 57.3 m, and the calculation result of strata movement model is 55.87 m.The deviation between them is relatively small. (4) the overburden rock of No. 8133 face of No. 8133 coal mine is affected by the developed strain-porosity permeability model. The change of permeability distribution is calculated. The results show that the strata near 55.87m above the goaf are affected by mining movement, the fractures are more developed, and the permeability changes greatly. Combined with the demand of gas treatment in coal mine, the optimization scheme of height design of high drainage roadway is put forward, which has a good effect on gas drainage in working face in actual engineering effect. The amount of gas drainage in high drainage roadway accounts for more than 96.76% of the total amount of gas drainage in working face. In this paper, a set of zonal calculation model of strata movement and the corresponding model of strain, porosity and permeability of strata are established. The reliability of the model is verified by field observation, simulation and analysis, and some engineering results are obtained. The results show that the theoretical results have good reliability and practicability. Through the research in this paper, the strata movement model and the strain-porosity permeability calculation model established for mining overburden rock are not only beneficial to underground gas drainage, but also can be further applied to control formation water gushing. Design surface water conservation mining plan, etc.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD325;TD712.6

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