淋水扰动下大倾角软煤综放面“支架—围岩”系统稳定性控制研究
发布时间：2018-12-15 12:04
【摘要】：顶板淋水事故易于引发大倾角软煤综放面“支架—围岩”系统失稳。针对长山子煤矿1125大倾角软煤综放面开采初期遭遇顶板淋水后引发的中下部支架倾倒事故,通过分析工作面覆岩结构及水文地质资料,确定了工作面顶板淋水原因;运用理论分析和建立物理力学模型,阐明了顶板淋水对支架稳定性和顶底板稳定性影响,研究了淋水扰动下顶板岩层的破坏机理及特征;根据煤层赋存条件,采用FLAC3D建立流固耦合数值模型研究了大倾角软煤综放面在顶板水作用下的围岩应力、位移及塑性破坏分布规律;最后制定了支架稳固方案及倾倒支架安全扶稳方案并付诸实施。具体研究结果如下:(1)1125工作面顶板淋水来源为其顶板侏罗纪新河组砂砾岩含水层孔隙裂隙水,淋水原因为软弱顶板岩层受开采扰动影响产生由下向上扩展的纵向裂隙,裂隙贯通至顶板砂砾岩含水层时形成导水通道,继而致使局部集聚的顶板水下淋。(2)顶板淋水对支架稳定性的扰动主要表现为淋水侵蚀软弱破碎顶板造成顶板抽冒;底板受淋水浸泡软化变形致使支架底座下陷,二者综合导致支架大范围空顶。支架底座间的浮煤与淋水作用形成煤泥,造成工作面底板湿滑,加剧了支架向下滑移的趋势。(3)顶板淋水扰动下1125工作面顶板岩层破坏机理为:采动裂隙随着工作面的推进不断发育在顶板岩层形成松动带,顶板淋水削弱了顶板岩层颗粒间的黏聚力,降低了顶板岩层的抗剪切强度,溶解了顶板岩层部分胶结物,泥化了破碎顶煤,降低了工作面顶板强度及稳定性。顶板水对松动带裂隙施加的裂隙水压力使其发生垂直变形、切向变形以及位移,打破了顶板岩层原有平衡,最终导致其出现贯穿性破坏面并引发失稳。(4)FLAC3D数值模拟结果表明,顶板水扰动下其顶板垂直应力呈不均匀无规则分布,应力扰动范围较大,顶板变形程度及顶板塑性破坏区较无水干涉条件下均显著增大,增加了大倾角软煤综放面顶板岩层失稳趋势。(5)支架稳固方案和倾倒支架动态扶稳方案有效控制了工作面水患,扶稳了受淋水影响倾倒的支架,确保了大倾角软煤综放面“支架—围岩”系统的稳定性。本论文研究结果对于解决水文条件相对简单的大倾角软煤综放面突发顶板淋水事故后引发“支架—围岩”系统失稳及推进缓慢问题具有借鉴意义,所确定的支架稳固方案及倾倒支架扶稳方案为大倾角软煤综放面安全通过淋水区域提供了保障。
[Abstract]:Roof flooding accidents are apt to lead to instability of "support-surrounding rock" system in fully mechanized coal caving face with large dip angle. In view of the caving accident of the middle and lower part of the fully mechanized caving face of Changshanzi coal mine during the initial stage of mining, the overburden structure and hydrogeological data of the working face are analyzed, and the reason of roof flooding is determined. Based on the theoretical analysis and the establishment of physical and mechanical models, the effects of roof water on the stability of the support and the roof and floor are expounded, and the failure mechanism and characteristics of the roof strata under the disturbance of water flooding are studied. According to the condition of coal seam occurrence, the numerical model of fluid-solid coupling is established by FLAC3D to study the distribution of surrounding rock stress, displacement and plastic failure of fully mechanized caving face with large dip angle under the action of roof water. Finally, the scheme of support stability and the safety support scheme of toppling bracket are worked out and put into practice. The concrete results are as follows: (1) the source of roof water in 1125 working face is pore fissure water of sandy gravel aquifer of Xinhe formation in the roof of Jurassic, which is caused by the influence of mining disturbance on weak roof strata, which is caused by the vertical fracture extending from the bottom up. When the fissure passes through to the sand and gravel aquifer of the roof, a water conduction channel is formed, which leads to the local accumulated roof underwater leaching. (2) the disturbance of roof water to the stability of the support is mainly caused by water erosion and weak broken roof, which results in the roof caving; The bottom plate is softened and deformed by drenching water, which results in the collapse of the base of the support, and the combination of the two causes the large-range hollow roof of the support. The floating coal between the base of the support and the dripping water form the coal slime, which causes the floor of the working face to be wet and slippery. (3) under the roof water disturbance, the failure mechanism of roof strata in 1125 working face is as follows: the mining fissure develops continuously in the loose zone of roof rock with the advance of working face. Roof flooding weakens the cohesion between roof rock particles, reduces the shear strength of roof rock, dissolves some cementing matter of roof rock, muddies broken top coal, and reduces the strength and stability of working face roof. The crack water pressure exerted by roof water on the crack in the loose zone causes the vertical deformation, tangential deformation and displacement, thus breaking the original balance of the roof rock layer. The results of FLAC3D numerical simulation show that the vertical stress of the roof is uneven and irregular, and the range of the stress disturbance is large. The degree of roof deformation and the plastic failure zone of roof are significantly increased compared with those under the condition of no water interference. The trend of instability of roof strata of soft coal caving face with large dip angle is increased. (5) the support stabilization scheme and the dynamic support scheme can effectively control the flood hazard of the working face and stabilize the support which is affected by the pouring water. It ensures the stability of the support-surrounding rock system of the fully mechanized top coal caving face with large dip angle. The results of this paper can be used for reference to solve the problem of "support surrounding rock" system instability and slow advance caused by sudden roof sprinkling accident in soft coal caving face with large dip angle, which is relatively simple in hydrological condition. The fixed support scheme and the toppling support scheme provide a guarantee for the safety of fully mechanized top-coal caving face with large dip angle through the flooded area.
【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】：TD355.4
[Abstract]:Roof flooding accidents are apt to lead to instability of "support-surrounding rock" system in fully mechanized coal caving face with large dip angle. In view of the caving accident of the middle and lower part of the fully mechanized caving face of Changshanzi coal mine during the initial stage of mining, the overburden structure and hydrogeological data of the working face are analyzed, and the reason of roof flooding is determined. Based on the theoretical analysis and the establishment of physical and mechanical models, the effects of roof water on the stability of the support and the roof and floor are expounded, and the failure mechanism and characteristics of the roof strata under the disturbance of water flooding are studied. According to the condition of coal seam occurrence, the numerical model of fluid-solid coupling is established by FLAC3D to study the distribution of surrounding rock stress, displacement and plastic failure of fully mechanized caving face with large dip angle under the action of roof water. Finally, the scheme of support stability and the safety support scheme of toppling bracket are worked out and put into practice. The concrete results are as follows: (1) the source of roof water in 1125 working face is pore fissure water of sandy gravel aquifer of Xinhe formation in the roof of Jurassic, which is caused by the influence of mining disturbance on weak roof strata, which is caused by the vertical fracture extending from the bottom up. When the fissure passes through to the sand and gravel aquifer of the roof, a water conduction channel is formed, which leads to the local accumulated roof underwater leaching. (2) the disturbance of roof water to the stability of the support is mainly caused by water erosion and weak broken roof, which results in the roof caving; The bottom plate is softened and deformed by drenching water, which results in the collapse of the base of the support, and the combination of the two causes the large-range hollow roof of the support. The floating coal between the base of the support and the dripping water form the coal slime, which causes the floor of the working face to be wet and slippery. (3) under the roof water disturbance, the failure mechanism of roof strata in 1125 working face is as follows: the mining fissure develops continuously in the loose zone of roof rock with the advance of working face. Roof flooding weakens the cohesion between roof rock particles, reduces the shear strength of roof rock, dissolves some cementing matter of roof rock, muddies broken top coal, and reduces the strength and stability of working face roof. The crack water pressure exerted by roof water on the crack in the loose zone causes the vertical deformation, tangential deformation and displacement, thus breaking the original balance of the roof rock layer. The results of FLAC3D numerical simulation show that the vertical stress of the roof is uneven and irregular, and the range of the stress disturbance is large. The degree of roof deformation and the plastic failure zone of roof are significantly increased compared with those under the condition of no water interference. The trend of instability of roof strata of soft coal caving face with large dip angle is increased. (5) the support stabilization scheme and the dynamic support scheme can effectively control the flood hazard of the working face and stabilize the support which is affected by the pouring water. It ensures the stability of the support-surrounding rock system of the fully mechanized top coal caving face with large dip angle. The results of this paper can be used for reference to solve the problem of "support surrounding rock" system instability and slow advance caused by sudden roof sprinkling accident in soft coal caving face with large dip angle, which is relatively simple in hydrological condition. The fixed support scheme and the toppling support scheme provide a guarantee for the safety of fully mechanized top-coal caving face with large dip angle through the flooded area.
【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】：TD355.4
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