共查询到20条相似文献，搜索用时 421 毫秒
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倾斜煤层沿空半煤岩巷由于围岩结构的非对称性和非均质性,受采掘扰动影响,巷道围岩呈现更严重的变形破坏。为揭示不同基本顶断裂形式对倾斜煤层沿空半煤岩巷围岩稳定性的影响规律,采用数值模拟方法针对该类巷道4种基本顶断裂形式下巷道围岩变形特征进行了研究。结果表明:基本顶断裂线位置对该类巷道围岩稳定性的影响程度由小到大依次为:采空区侧、煤柱上方、实体煤侧、巷道上方;基本顶断裂线位于采空区侧时,煤柱轴向、横向应力增速均小于其他情况,垂直位移也最小,煤柱变形在允许范围内,可保持后期对顶板的支承能力,对巷道维护最有利。在此基础上,以贵州某矿1511工作面回风巷为工程背景进行了工业试验,通过理论计算和现场钻孔探测综合分析得出,为避免基本顶断裂线位于煤柱上方靠巷道侧,下一步掘进时煤柱宽度应由3 m改为5 m。掘采期间断面检测结果显示,断面最大收缩率为23.3％,最大非对称变形率为5.2％,巷道整体均匀协调变形,进一步验证了研究成果的可靠性。 相似文献
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This study investigates the flow and caving characteristics of top coal and roof rock, as well as top coal loss pattern in the fully mechanized top coal caving mining of extra thick coal seams. The two dimensional discrete element numerical simulation software program, particle flow code (PFC), is used for the simulation of top coal caving and the inversion analysis. The original locations, distribution, and migration pattern of caved top coal and lost coal were obtained. The analysis shows that in the initial site of caving, the caved bodies are in the form of arc shaped strips in front of the working face. During the caving, caved bodies of different heights move towards the lower rear of the face at different speeds. The lost coal and caved roof rock are originally located at the interface between coal seam and roof, the lost coal is mainly distributed in the goaf on the floor. Behind the support, the caved top coal bodies originally are arc shaped strips, with the highest points located at the midline of the caving opening. The strips are more curved near the goaf than those near the support. During top coal caving, the strips successively cave, with the adjacent outer strip replacing the caved one. The variations of top coal loss and waste rock ratio with time reflect the different phases of top coal caving. In order to improve coal recovery and limit the amount of caved roof rock, the waste rock ratio should be controlled below 10 %. When the waste rock ratio reaches this value, the caving opening should be closed. This paper provides theoretical bases for the improvement of top coal recovery in the fully mechanized top coal caving mining of extra thick coal seams. 相似文献
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Continuous air leakage from ground mining-induced cracks is a significant cause of coal spontaneous combustion, low oxygen at the working face and other disasters in shallow coal seams. This paper studies mining-induced cracks and air leakage caused by the repeated mining of shallow coal seams at the Bulianta coal mine, Shendong Coalfield, China. A similar simulation experiment was carried out in the laboratory, and then the ground mining-induced cracks were observed and the crack air leakage was detected. The results showed that the surface air flowed into the composite goaf before the fractures redeveloped to the surface during the process of lower coal seam mining. Due to the different development processes of vertical fractures in various regions, the width of the vertical fractures in the boundary area of the overlying goaf increases significantly after the repeated mining of coal seams, while the vertical fractures in the central area of the overlying goaf experience almost no change. The distribution of the surface air leakage cracks is in the shape of “回”. Graben-type cracks and half-graben-type cracks are surface air leakage cracks, which are the focus of surface air leakage problems, especially the half-graben-type cracks. The results are important in engineering for reducing air leakage from surface mining-induced cracks. 相似文献
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鄂尔多斯盆地北部侏罗纪深埋区中生代地层以河流相沉积为主,呈分阶段的多旋回演化特点,导致煤层顶板含隔水层交替分布;由于地表大部分为毛乌素沙漠,降水入渗补给系数大,第四系松散层储水能力强,充足的补给水源造成煤层顶板直接充水含水层富水性较强,其中最主要的充水含水层为七里镇砂岩,以七里镇砂岩为关键层,将煤层至七里镇砂岩概化为一个直接充水含水层。承压水井大降深抽水时,当井中水位低于含水层顶板,井附近的含水层会出现无压水流区,形成承压–无压水井,采用分段法计算流向井的流量,包括无压水区和承压水区。实际工作面回采过程中,井中水位已降低至煤层底板;传统的承压–无压水井公式假设条件为井径较小(≤m级),而实际工作面回采过程中,随着覆岩导水裂隙带对七里镇砂岩关键充水含水层的破坏,导致整个煤层顶板形成巨大的采空区疏水井(102~103 m级),且该采空区疏水井半径逐渐增大,传统公式适用性不高。基于《地下水动力学》中的承压–无压水井公式,结合鄂尔多斯盆地北部深埋煤炭开采过程中采空区疏水井演化过程,建立适合于深埋区开采扰动下的采空区疏水井承压–无压水公式;以葫芦素煤矿首采工作面为研究对象,利用地质勘探和井下揭露获得的相关水文地质参数,计算葫芦素煤矿首采工作面回采过程中涌水量。结果表明:工作面回采初期,由于导水裂隙带未充分发育,尚未沟通七里镇砂岩,此阶段实际涌水量偏小;中后期导水裂隙带发育至七里镇砂岩,涌水量计算值与实际值较为接近,证明深埋煤层工作面涌水量计算公式可较准确地预测研究区工作面回采过程中的涌水量。本次建立的深埋工作面涌水量计算公式,广泛适用于我国西部侏罗纪煤田区,可为深埋煤田区煤炭资源安全开采提供科学的水害防治依据。 相似文献
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基于切顶卸压自动成巷技术原理,分析了沿空切顶巷道顶板结构演化过程,得出厚煤层快速回采切顶成巷围岩应力、位移传递机制,形成了人为主动构建“基本顶上位岩层-采空区碎胀矸石-巷道切顶短臂梁”围岩稳定结构的控制思路。提出厚煤层快速回采沿空切顶巷道围岩协同控制体系,以“恒阻大变形锚索+墩式单元支架”控制顶板,以“滑移式让位护帮结构+自移式动压防冲结构+波浪式多阻护帮锚杆”控制帮部,形成了应对顶板结构位态、碎石运动状态变化的针对性控制技术。以柠条塔煤矿S1201胶运顺槽为工程背景,完成了厚煤层快速回采条件下切顶卸压无煤柱自成巷现场工业性试验。研究表明,采高增大、采速加快后,基本顶上位岩层易引发少量不宜强制控制的回转变形,支护结构可控让位是构建围岩稳定结构的有效途径之一;巷内压力与采空区矸石运动状态密切相关,增强预裂效果有利于减少动压冲击;成巷过程中巷道顶压首先达到恒阻状态,而后位移趋于稳定,最后形成围岩稳定结构。所设计的配套支护结构可有效协同围岩运动,留巷效果良好。 相似文献
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蒙陕接壤区侏罗系深埋煤层开采过程中,掌握不同阶段矿井涌水量变化规律,是保障煤矿安全的关键。从含水层发育特征、巷道掘进进尺、采空区半径等方面开展了相关研究,结果表明:蒙陕接壤区煤层顶板导水裂缝带范围内的3层复合含水层,富水性差异较大,分别对巷道掘进阶段和工作面回采阶段涌水量影响较大。煤矿建井阶段,矿井涌水量随着巷道掘进进尺增加而增加,但单位进尺涌水量变化不大,平均涌水量为0.008 32 m3/（h·m）。工作面回采前将钻孔水量降至5.0 m3/h以下,水压降至1.0 MPa左右,实现了顶板含水层静储量充分疏放目标。首采面和接续面回采阶段,矿井涌水量呈"阶梯式"平稳增加,矿井涌水量与采空区半径呈线性正相关关系。通过对侏罗系深埋煤层开采过程中矿井涌水量变化规律和影响因素的研究,可以为其他矿井建设和工作面回采提供安全保障和科学依据。 相似文献
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为研究深部煤层开采底板破坏形态,提出考虑围岩应变软化和采空区接触的FLAC3D有限差分数值方法,以河北开平煤田林西矿2023工作面底板实测导水裂隙带为工程背景,结合朗肯土压力理论定性分析,研究深部煤层底板破坏特征。结果表明:采用应变软化本构关系代替常用摩尔–库伦本构关系能够对围岩塑性破坏后的力学状态更准确表述;采用“应变软化–空–弹性”模型转变的方法,达到模拟采空区顶板垮落后应力传递的效果,弥补了以往煤层开采模拟中采空区垮落后顶底板不接触的固有缺陷;通过采空区顶底板接触与否条件下应力、位移的对比,发现采空区是否接触对数值结果影响巨大,突出考虑采空区接触的必要性;根据模拟结果中塑性剪切应变率的变化,实现了底板滑移面的三维显示,形态为斜向采空区的半包围面状结构;结合朗肯土压力理论将底板塑性区与主动区、过渡区和被动区对应,3个区破坏形式分别为剪切破坏、剪切破坏、拉张与剪切的交互破坏。提出的考虑围岩应变软化及采空区接触的FLAC3D数值方法对煤层开采模拟实现了优化,并可为其他大变形后需考虑接触的工程模拟提供参考。 相似文献
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In order to master the tendency mining-fracture-evolution characteristics of overlying strata and coal seams above working face with large inclination angle and mining depth in mining process, the 1221 working face in Zhao mine is selected as the engineering background and a mathematical model is established. The displacement variation, stress and strain of overlying strata and coal seams are simulated by using ANSYS software. In the mining process, the movement characteristics, displacement variation laws and fracture evolution characteristics of overlying strata and coal seams above working face with large inclination angle and mining depth along inclination direction are discussed. Simulation results show that with the advance of working face, the fracture development of overlying strata and coal seams is larger and larger; the area of gob is gradually expanding and the transverse stress of overlying strata and coal seams is also expanding. Stress contour of overlying strata and coal seams at both ends of gob becomes denser and denser; the activity of the overlying strata and coal seams near the up-roadway side of the gob is violent. The pressure relief zone is formed in the upper part of the strata and the roof above the gob. Large inclination angle of coal seam results in larger supporting pressure in the underside of the gob and smaller supporting pressure in the upper side of the gob. Along the inclination direction of the working face, the pressure relief zone is mainly concentrated in the outlet roadway of the working face; the fracture development and strata separation are obvious, which offer good passage for gas flow and migration. 相似文献
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Solid backfill mining has apparent technical advantages in extracting coal resource under sensitive surface structures such as buildings and roads; meanwhile, as an effective method of disposing mining wastes, it works well in solving some environmental problems caused by mining activities. In addition, the controlling effect of solid backfill mining is directly related to the compaction characteristic of backfilling materials. The present study aims to modify the backfilling materials by assessing the effect of binders (cement, fly ash, and lime) on the compaction characteristic of granulated gangue backfilling materials. The compaction test was performed with rock mechanic test system equipped with a self-made circular cylinder apparatus. From the results obtained, cement is not the suitable binder for modifying the gangues backfilling materials, while fly ash or lime, when the dosage is up to 20 wt%, is beneficial to the compaction characteristic of backfilling materials. The relationship between strain behavior and micro-structure of backfilling materials was investigated by SEM and the effect of fly ash or lime on the strain behavior of backfilling materials could be associated with its cementation and gap-filling effect. 相似文献
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宁夏石嘴山矿区位于西部黄河流域,其煤矿采空区沉陷导致地表生态和环境问题频发,对其采煤沉陷分析将对西部黄河流域煤矿区的环境修复有一定的积极作用。为研究缓倾斜煤层采空区围岩应力与位移场演化特征,以宁夏石嘴山矿区为对象,基于FLAC3D数值模拟软件,建立缓斜煤层开采三维数值模型,计算分析采空区围岩应力、塑性区及位移变化规律,并基于两时相DEM叠加统计分析地表位移变化,与数值模拟结果进行相互验证。结果表明:地下开采引起应力重分布,采空区顶板及煤柱出现明显的应力集中现象,最大主应力呈现从煤层顶板向地表递减的变化趋势;越靠近采空区顶部的岩层垂直位移越大,随着远离采空区逐渐减少,开采完成后地表垂直位移最大值约12 m;随着采空区面积的不断增大,采空区四周及角隅处塑性区逐步延伸扩大,且以剪切破坏为主;地面沉陷盆地不对称,2个沉降中心均发生在沉陷盆地中部且偏下山方向,下山方向比上山方向影响范围更大;数值模拟计算的沉降量与两时相DEM叠加统计分析的变化量结果及趋势基本一致,研究成果可为煤炭安全开采提供参考依据,为地表沉降监测提供新方法。 相似文献
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为研究深部近距离煤层群下向卸压开采高应力演化的特征,根据潘二煤矿深部近距离煤层群8煤和6煤地质与开采技术条件,设计了下向卸压开采的二维相似材料模拟试验模型,对8煤和6煤开采引起的采动应力进行监测。系统分析了8煤下向开采与6煤开采后的采场围岩采动应力、岩层运移及不规则煤柱对采动应力演化的影响,获得了近距离煤层群8煤下向卸压开采的顶底板采动高应力演化特征及6煤回采期间覆岩运移、采动应力裂隙演化和来压特征,得出了下向卸压开采不规则煤柱对采动应力、裂隙分布的影响规律。研究不仅为以采动高应力演化为主导作用的煤岩动力灾害防治提供了理论基础,也为卸压开采采场参数设计与优化提供了技术支撑。 相似文献
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Jixiong Zhang Qiang Sun Nan Zhou Jiang Haiqiang Deon Germain Sami Abro 《Arabian Journal of Geosciences》2016,9(10):558
In China’s western coal mining area, the traditional room mining technology is facing coal pillar instability, mine earthquake, large-area roof subsidence in the goaf, surface subsidence, water and soil loss, vegetation deterioration, and other environmental problems. To solve the aforementioned problems and to improve coal recovery, the roadway backfill coal mining (RBCM) method was proposed as a solution and its technical principle and key equipment were presented in this paper. In addition, the microstructure and mechanical behavior (strain-stress relation in confined compressive test) of aeolian sand and loess backfill materials were studied for a rational backfill design for underground mines. Further, coal pillar stress, plastic zone change, and surface deformation of the RBCM schemes were studied using the FLAC3D numerical simulation software, and a reasonable mining scheme of “mining 7 m and leaving 3 m” was determined. The engineering application in Changxing Coal Mine shows that the RBCM method with loess and aeolian sand as backfill materials allows a stable recovery of coal pillars with a recovery ratio of more than 70 %. The maximum accumulated surface subsidence and the maximum horizontal deformation were measured to be 15 mm and 0.8 mm/m respectively, indicating that the targeted backfilling effect can help protect the environment and also control surface subsidence. 相似文献
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概率积分法是煤矿开采沉陷预测的重要方法,可适用于缓倾斜、倾斜煤层开采地表移动分布曲线符合正态分布规律的地表移动和变形计算。针对原方法对任意形状工作面存在的不足,在原有走向和倾向概率积分函数的基础上,以走向和倾向为基准划分积分函数区域,在该区域内剖分非结构化的三角形单元作为二重积分的基本单位;通过坐标旋转变换的二重积分换元法,转化为以直线为上、下限的二重积分,计算旋转后的影响半径,对新的二重积分采用复合辛普森数值积分公式,积分得出地表任意点在基本三角形开采单元下的积分下沉值;最后,通过叠加计算完成任意点、任意形状工作面概率积分法的沉陷预测计算。算法在GIS系统下实现,实例应用效果良好,可为“三下”采煤提供地表移动预测计算的支持。 相似文献
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采用理论分析与实践、实测相结合的方法,对急倾斜煤层工作面下端头区沿空留巷技术理论及系统工艺问题进行探讨,弄清了充填体受力的影响因素,提出了急倾斜煤层巷旁充填工艺系统。研究表明,急倾斜煤层巷旁充填体承载受采空区矸石有效充填长度、煤层赋存倾角、充填体筑设宽度以及煤岩赋存厚度的影响,受顶底板锚索安设的影响较小;单轴压缩条件下矸石碎块的承载变形规律呈阶段特征,且每一阶段内的应力-应变近似呈线性关系;充填体的承载与变形随着距离工作面位置的不同具有阶段特征,距离工作面煤壁越远,充填体承载变形率越小;以七台河新强煤矿生产实际为背景,现场实践证明,急倾斜煤层矸石混凝土充填工艺系统实施方便、操作简单,沿空留巷整体效果较为明显。 相似文献
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浅埋煤层上覆采空区水威胁着陕北地区诸多煤矿的安全生产。以陕北地区某煤矿为例,针对该类水害问题进行分析,通过经验公式、数值模拟等方法计算,开采3-1号煤层产生的覆岩导水裂缝带高度至少为66 m,运用类比法及经验公式预计,矿井正常涌水量为163 m3/h,最大涌水量203 m3/h,3-1号煤层上覆采空区积水量约为2.6×106 m3。根据各计算结果,提出"物探先行、钻探验排、先治后采、有掘必探"的安全开采技术方案和思路,为矿井后期制定合理有效的煤层顶板采空区水综合防治措施打好基础。 相似文献
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针对急倾斜软硬互层巷道围岩大变形控制难题,采用现场试验、理论分析和数值仿真等多种手段,研究急倾斜巷道围岩变形破坏机制,研究结果表明：急倾斜软硬互层巷道的变形与破坏具有非对称性,偏压作用明显,呈现顶板下滑,底板臌起的相互错动变形特征,底臌严重且易片帮冒顶。巷道断面与岩层倾斜方向的钝角部位受侧向约束小,因而剪切滑移变形较大,是产生非对称变形破坏的关键部位;下帮围岩变形破坏较上帮更为严重。基于急倾斜巷道的变形破坏特点,提出在锚- 网-索耦合支护的基础上利用锚索、底角锚杆等对产生差异变形破坏的关键部位进行加强支护的方法,巷道大变形得到了有效控制。 相似文献
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急倾斜厚大金属矿山地下开挖岩移发生机理 总被引：1，自引：0，他引：1
文章以金川二矿区的岩体移动为例,对急倾斜厚大金属矿山的岩体移动这一重大工程难题进行了探讨。分析了急倾斜金属矿山开挖引起岩体移动的概化传递模式及其地表岩移显现特征。结合数值模拟及GPS监测分析结果,对厚大急倾斜金属矿山岩移发生机理进行研究。结果表明,急倾斜金属矿的厚度对地表岩移的显现特征具明显的影响。当对厚大矿体进行薄层开采时,较大幅度的岩体移动主要发生在采空区顶、底板,开采引起岩体移动的地表显现特征类似于水平矿体的开采;而当采空区的高度大于整个矿体的厚度时,采空区两侧的岩体位移逐渐增大到占主导地位。岩体移动的地表显现特征开始表现为急倾斜矿体开挖的岩体移动特征。 相似文献