浅埋煤层开采岩层移动规律及地表沉陷预测研究
发布时间：2019-04-12 14:49
【摘要】：浅埋煤层开采常采用长壁式综采,全部垮落法管理顶板,这使得岩层移动剧烈,地表沉陷量较大。本文采用理论模型分析、地表沉陷观测及数值模拟的研究方法,对浅埋煤层开采后的岩层移动及地表沉陷进行了深入研究。浅埋煤层开采后岩层移动无弯曲下沉带,上覆岩土层呈“三带”(冒落带、裂隙带和松散层)分布。冒落带紧邻采空区,随着煤层开采后立即垮落,且破断块度较小。裂隙带位于冒落带上侧,岩层破断块度较大,且在破断后能保持层状分布。地表松散层颗粒介质较分散,移动具有随机介质移动的特点,并在地表形成沉陷盆地。在冒落带垮落前,将采空区简化为椭圆形洞室,分析得到冒落带岩层应力;随着煤层的开采,未垮落的冒落带岩层简化为悬臂梁,计算得到冒落带岩层应力,结合岩层破断条件得到冒落带岩层的破断机理。总结破碎岩石的碎胀系数,得到了岩层的沉陷经验值。岩层移动中关键层起着重要作用,通过简化建立了关键层弹性地基梁模型,并求解得到了关键层的弯矩、剪力、挠度和转角的解析解。结合岩梁破断条件,得到关键层初次破断距和周期破断距。将模型应用到实际工程中,结果表明关键层弹性地基量模型可较好估算关键层的破断距。应用随机介质理论得到了单元开采的地表沉陷曲线,并积分得到半无限开采地表沉陷预测公式。将有限开采视为两个无限开采之和的1/2,得到了有限开采的地表沉陷预测公式。对沉陷参数进行回归分析,得到岩性与沉陷参数的关系。对地表沉陷进行实际观测,获得了地表沉陷实测值。对比理论预测与观测结果,两者吻合程度较高,理论模型可较好应用在浅埋煤层地表沉陷预测中。建立了浅埋煤层开采UDEC模型,模拟分步开采过程,得到岩层移动动态规律。对比数值模拟和观测成果,两者的相对误差较小。这说明数值模拟可较好应用在浅埋煤层地表沉陷预测中。
[Abstract]:Long-wall fully mechanized mining is often used in shallow coal seam mining, and roof is managed by all caving method, which makes the rock strata move violently and the subsidence amount of the surface is large. In this paper, theoretical model analysis, surface subsidence observation and numerical simulation are used to study the strata movement and surface subsidence after mining in shallow coal seam. After mining in shallow coal seam, the strata move without bending subsidence zone, and the overlying rock layer is distributed as "three zones" (fall zone, fracture zone and loose layer). The caving zone is adjacent to the goaf, and it collapses immediately after coal seam mining, and the breaking block degree is smaller. The fracture zone is located on the upper side of the caving zone. The fracture block degree of the rock layer is large, and the layer distribution can be maintained after the fracture. The granular medium in the surface loose layer is dispersed and has the characteristics of random medium movement, and the subsidence basin is formed on the surface of the earth. Before the caving zone collapses, the goaf is simplified to an oval chamber, and the rock stress in the caving zone is analyzed. With the mining of coal seam, the rock layer of the uncollapsed caving zone is simplified to cantilever beam, the stress of the falling zone is calculated, and the breaking mechanism of the caving zone is obtained by combining the breaking conditions of the strata. The coefficient of crushing expansion of broken rock is summarized, and the experiential value of rock subsidence is obtained. The key layer plays an important role in rock movement. By simplifying the elastic foundation beam model of the key layer, the analytical solutions of bending moment, shear force, deflection and rotation angle of the key layer are obtained. Combined with the rock beam breaking conditions, the initial breaking distance and the periodic breaking distance of the key strata are obtained. The model is applied to practical engineering, and the results show that the elastic foundation model of the key layer can estimate the breaking distance of the critical layer well. The surface subsidence curve of unit mining is obtained by using random medium theory, and the prediction formula of semi-infinite mining surface subsidence is obtained by integral. The finite mining is regarded as the sum of two infinite mining, and the prediction formula of surface subsidence of limited mining is obtained. The relationship between lithology and subsidence parameters is obtained by regression analysis of subsidence parameters. The actual observation of the surface subsidence is carried out, and the measured value of the surface subsidence is obtained. The theoretical prediction and observation results are in good agreement with each other. The theoretical model can be applied to the prediction of surface subsidence in shallow coal seam. The UDEC model of shallow coal seam mining is established to simulate the step-by-step mining process and obtain the dynamic law of strata movement. Compared with the results of numerical simulation and observation, the relative error between them is relatively small. This shows that the numerical simulation can be applied to the prediction of surface subsidence in shallow coal seam.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD325
本文编号：2457113
[Abstract]:Long-wall fully mechanized mining is often used in shallow coal seam mining, and roof is managed by all caving method, which makes the rock strata move violently and the subsidence amount of the surface is large. In this paper, theoretical model analysis, surface subsidence observation and numerical simulation are used to study the strata movement and surface subsidence after mining in shallow coal seam. After mining in shallow coal seam, the strata move without bending subsidence zone, and the overlying rock layer is distributed as "three zones" (fall zone, fracture zone and loose layer). The caving zone is adjacent to the goaf, and it collapses immediately after coal seam mining, and the breaking block degree is smaller. The fracture zone is located on the upper side of the caving zone. The fracture block degree of the rock layer is large, and the layer distribution can be maintained after the fracture. The granular medium in the surface loose layer is dispersed and has the characteristics of random medium movement, and the subsidence basin is formed on the surface of the earth. Before the caving zone collapses, the goaf is simplified to an oval chamber, and the rock stress in the caving zone is analyzed. With the mining of coal seam, the rock layer of the uncollapsed caving zone is simplified to cantilever beam, the stress of the falling zone is calculated, and the breaking mechanism of the caving zone is obtained by combining the breaking conditions of the strata. The coefficient of crushing expansion of broken rock is summarized, and the experiential value of rock subsidence is obtained. The key layer plays an important role in rock movement. By simplifying the elastic foundation beam model of the key layer, the analytical solutions of bending moment, shear force, deflection and rotation angle of the key layer are obtained. Combined with the rock beam breaking conditions, the initial breaking distance and the periodic breaking distance of the key strata are obtained. The model is applied to practical engineering, and the results show that the elastic foundation model of the key layer can estimate the breaking distance of the critical layer well. The surface subsidence curve of unit mining is obtained by using random medium theory, and the prediction formula of semi-infinite mining surface subsidence is obtained by integral. The finite mining is regarded as the sum of two infinite mining, and the prediction formula of surface subsidence of limited mining is obtained. The relationship between lithology and subsidence parameters is obtained by regression analysis of subsidence parameters. The actual observation of the surface subsidence is carried out, and the measured value of the surface subsidence is obtained. The theoretical prediction and observation results are in good agreement with each other. The theoretical model can be applied to the prediction of surface subsidence in shallow coal seam. The UDEC model of shallow coal seam mining is established to simulate the step-by-step mining process and obtain the dynamic law of strata movement. Compared with the results of numerical simulation and observation, the relative error between them is relatively small. This shows that the numerical simulation can be applied to the prediction of surface subsidence in shallow coal seam.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD325
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