小纪汗煤矿含水煤层巷道变形机理研究

发布时间：2018-07-09 16:40

本文选题：含水煤层 + 底板强度弱化　；参考：《中国矿业大学》2015年硕士论文

【摘要】：水害一直是制约煤矿安全生产的重大隐患之一,矿井在巷道掘进时期,围岩因吸水膨胀其强度弱化、变形加剧,而井下疏排水引起巷道断面尺寸变化更会加剧巷道围岩变形。小纪汗煤矿首次发现煤层为含水层且为主要承压含水层,在此特殊水文地质工程背景下,开展含水煤层巷道变形机理研究,对指导矿井安全生产具有重要的理论与实际意义。论文主要研究内容及成果如下:(1)针对该矿井巷道底板条件,现场取样对底板岩石矿物组成成分、岩石膨胀性、水作用下岩石强度弱化规律进行系统的试验研究。发现岩石中含蒙脱石、伊利石等膨胀性矿物质是围岩膨胀变形的微观影响因素,底板岩石遇水后产生的高膨胀应力、较大变形量宏观表象为围岩变形。给出巷道底板粉砂质泥岩抗拉强度、单轴抗压强度及弹性模量随含水率、不同浸水时间变化而弱化规律函数,为数值模拟研究提供参数依据。(2)运用岩体弹塑性力学知识,考虑围岩体强度衰减和应变软化特点,对巷道围岩塑性区半径及变形特征展开理论研究,给出围岩塑性区半径、围岩内任意一点应力和巷道表面围岩位移量的解析式。发现相比无水作用下,水作用后巷道塑性区半径明显增大,巷道围岩表面位移量随岩石软化程度增加而增大。(3)建立不同含水率状态下巷道围岩数值计算模型,FLAC3D数值分析巷道开挖过程围岩强度特性随含水量增大而弱化特征,模拟研究巷道围岩应力应变、塑性区分布及围岩表面变形量,发现围岩变形量随岩石含水率增加而增大,从而揭示含水煤层巷道围岩变形基本原理及规律。(4)结合小纪汗煤矿巷道围岩破坏特征工程实际,分析围岩变形影响因素为地下水对底板岩层强度的软化及围岩遇水膨胀。统计分析巷道围岩各点变形量,结果表明数值计算分析与现场实测规律一致。本文以小纪汗煤矿含水煤层巷道为研究对象,研究成果应用于现场工程设计及施工,表明开展含水煤层巷道变形机理研究对矿井安全生产具有重要意义。
[Abstract]:Water hazard has always been one of the major hidden dangers restricting the safe production of coal mine. In the period of roadway excavation, the strength of surrounding rock is weakened due to water absorption and swelling, and the deformation is aggravated, while the change of tunnel section size caused by underground drainage will aggravate the deformation of roadway surrounding rock. It is the first time that coal seam is found as aquifer and main confined aquifer in Xiaojihan coal mine. Under this special hydrogeological engineering background, it is of great theoretical and practical significance to study the mechanism of roadway deformation in water-bearing coal seam. The main contents and achievements of this paper are as follows: (1) according to the conditions of the mine roadway floor, the rock mineral composition, rock expansion and the weakening law of rock strength under the action of water are systematically studied by field sampling. It is found that the swelling minerals such as montmorillonite and Illite are the microcosmic factors influencing the swelling deformation of the surrounding rock. The high expansion stress of the bottom rock and the macroscopic appearance of the large amount of deformation are the deformation of the surrounding rock. The function of weakening law of tensile strength, uniaxial compressive strength and elastic modulus of silty mudstone in roadway floor with water content and different soaking time is given, which provides parameter basis for numerical simulation. (2) using elastoplastic mechanics knowledge of rock mass. Considering the characteristics of strength attenuation and strain softening of surrounding rock mass, the radius and deformation characteristics of surrounding rock plastic zone of roadway are studied theoretically. The analytical formulas of radius of plastic zone of surrounding rock, stress of any point in surrounding rock and displacement of surrounding rock surface of roadway are given. It is found that the radius of the plastic zone of the roadway increases obviously after the action of water compared with that under the action of no water. The displacement of surrounding rock surface increases with the increase of rock softening degree. (3) the numerical calculation model of surrounding rock in different water content is established and FLAC3D numerical analysis shows that the strength characteristic of surrounding rock weakens with the increase of water content in roadway excavation process. The stress and strain of surrounding rock, the distribution of plastic zone and the amount of deformation of surrounding rock surface are simulated. It is found that the deformation of surrounding rock increases with the increase of water content of rock. Therefore, the basic principle and law of surrounding rock deformation in water-bearing coal seam roadway are revealed. (4) in combination with the engineering practice of surrounding rock failure characteristics of roadway in Xiaojihan coal mine, the influencing factors of surrounding rock deformation are the softening of underground water to the strength of floor rock and the swelling of surrounding rock in water. The results show that the numerical analysis is consistent with the field measurement. This paper takes the water-bearing coal seam roadway of Xiaojihan coal mine as the research object, and the research results are applied to the field engineering design and construction, which indicates that the research on the deformation mechanism of the water-bearing coal seam roadway is of great significance to the mine safety production.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD322

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