寨崖底矿下位煤层巷道围岩变形机理及加固技术研究

发布时间：2018-10-10 16:16

【摘要】：煤层开采引起采场周围岩体应力的重新分布,在回采空间前后方及两侧的煤体和煤柱上出现应力增高区,在回采空间边缘出现应力降低区。充分利用开采引起的围岩应力的分布规律,将下煤层回采巷道布置在采空区下方,使巷道位于应力降低区内,但是下煤层回采巷道与回采空间位置和采掘时间关系的不同,引起巷道围岩应力变化和围岩变形的不同,下煤层回采巷道受邻近上煤层工作面回采时,又受到上煤层邻近工作面回采动压影响。本文针对寨崖底矿下煤层巷道变形严重的问题,运用理论分析、数值模拟、现场调查和工业性试验相结合的方法,对受邻近上煤层工作面采动影响的下煤层巷道的围岩破坏机理进行了分析,研究了寨崖底矿下煤层回采巷道变形原因并提出了可靠的加固技术,主要内容如下:(1)失稳机理:通过理论计算、数值模拟、现场实测分析了下煤层3905回风顺槽的破坏原因;得出下煤层回采巷道失稳的根本原因在于邻近上煤层工作面回采动压影响导致煤柱附近采空区下水平应力相对变化远远大于垂直应力的相对变化,水平应力峰值是垂直应力峰值的5倍,整个巷道承受较大的水平应力,顶底板剪切破坏严重。(2)加固技术:提出“大直径高预应力锚索+单体液压支柱辅助支护”技术,很好地控制在采动动压影响下导致的水平应力过大而致使巷道剪切变形严重问题。预应力锚索使巷道顶板在原支护系统下的顶板保持整体性,发挥原支护系统性能,防止锚杆锚索破断连锁反应。单体液压支柱辅助支护,能够有效的应对采动过程中顶板应力的急剧调整。“预应力锚索+单体液压支柱辅助支护”从根本上控制了巷道变形破坏,保证了巷道顶板的安全有效使用。(3)工业实践:提出了寨崖底矿下煤层受邻近上煤层工作面采动及煤柱集中应力影响下的巷道控制围岩的加固技术并成功进行了工业性试验。寨崖底矿下煤层动压回采巷道采用“大直径高预紧力锚索+单体液压支柱辅助支护”加固支护技术,有效控制了巷道围岩强烈变形,并取得良好的支护效果,为类似条件的巷道支护提供了参考价值。
[Abstract]:Because of the redistribution of rock stress around the stope caused by coal seam mining, the stress increasing area appears in the coal body and pillar before and after the mining space and on both sides, and the stress decreasing area appears at the edge of the mining space. In order to make full use of the distribution law of surrounding rock stress caused by mining, the mining roadway of the lower coal seam is arranged under the goaf to make the roadway located in the stress reduction area, but the relationship between the space position and the mining time of the mining roadway in the lower coal seam is different. The change of surrounding rock stress and the deformation of surrounding rock of roadway are different. When the roadway of lower coal seam is mined by the adjacent upper coal face, it is also affected by the dynamic pressure of mining near the upper coal seam. In this paper, aiming at the serious problem of roadway deformation under Ziya coal mine, the method of combining theoretical analysis, numerical simulation, field investigation and industrial test is used. In this paper, the failure mechanism of surrounding rock of roadway in lower coal seam affected by mining movement of adjacent upper coal face is analyzed, the reason of deformation of mining roadway under coal seam under Zhaiya coal mine is studied, and the reliable reinforcement technology is put forward. The main contents are as follows: (1) the mechanism of instability: through theoretical calculation, numerical simulation and field measurement, the failure reasons of the 3905 return air trench in the lower coal seam are analyzed; It is concluded that the fundamental reason for the instability of mining roadway in the lower coal seam is that the influence of the mining dynamic pressure on the adjacent upper coal face results in the relative variation of horizontal stress in the goaf near the coal pillar far greater than the relative change of the vertical stress. The peak value of horizontal stress is 5 times of the peak value of vertical stress. The whole roadway bears large horizontal stress, and the roof and floor shear damage is serious. (2) strengthening technology: the technique of "large diameter and high prestressed anchor single hydraulic support" is put forward. Under the influence of mining dynamic pressure, the horizontal stress is too large, which leads to the serious problem of shear deformation of roadway. The prestressed anchor cable keeps the roof of the roadway roof intact under the original support system, exerts the performance of the original support system, and prevents the chain reaction of bolt and anchor cable breaking. Single hydraulic prop support can effectively cope with the sharp adjustment of roof stress in mining process. "Pre-stressed Anchorage cable single hydraulic prop auxiliary support" has fundamentally controlled the roadway deformation and destruction, It ensures the safe and effective use of roadway roof. (3) Industrial practice: the reinforcement technology of roadway controlling surrounding rock under the influence of mining movement of adjacent upper coal face and coal pillar concentration stress under the coal seam under Zhaiya coal mine is put forward and the industrial test is carried out successfully. Under the coal seam dynamic pressure mining roadway of Zhaiya coal mine, the "large diameter and high pretension anchor cable single hydraulic prop auxiliary support" is used to strengthen and support the roadway, which effectively controls the strong deformation of the surrounding rock of the roadway, and obtains good supporting effect. It provides reference value for roadway support under similar conditions.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TD353

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