孙疃煤矿7_211工作面基岩风化带特征

煤层顶板基岩风化带特性决定了其隔水能力的强弱。通过分析孙疃煤矿7211工作面72煤层顶板基岩风化带的岩性特征、矿物成分、水理性质及物理力学性质、风化带分布特征等因素,表明:该工作面基岩风化带岩屑矿物主要为石英和长石;古地形对风化带的发育厚度变化影响较明显;风化带具有一定的隔水能力,具有抑制冒落带与导水裂隙带向上发育的作用,这对缩小防水煤岩柱、合理留设安全煤岩柱高度和回采上限十分有利。     

“四含”水体下留设防砂煤岩柱开采可行性研究

通过对童亭煤矿水文地质条件分析,证实“四含”属弱含水层,以静储量为主,补给水源不足,而矿井为防止“四含”水进入矿坑,留设了厚层防水煤岩柱,使大量的煤炭资源被压,造成资源的浪费。为解放防水煤柱,提高回采上限,达到提高资源的回采率,根据童亭煤矿开采的地质条件与水文地质条件,计算出冒落带高度、保护层厚度、防砂煤岩柱厚度、以及工作面回采时的最大涌水量,从而确定回采上限标高为-235m,将回采上限提高了30m。340工作面留设防砂煤岩柱开采的实验成功,为工作面上提开采提供了可靠的地质依据。     

巨厚松散层下采煤防砂煤岩柱留设的实践

两淮地区的大多煤系被巨厚松散层覆盖,而松散层底部的第四含水层直接覆于煤系之上,威胁煤矿安全生产。为防止“四含”水进入矿井,矿井留设了厚层防水煤岩柱,这使过多的浅部煤炭资源积压。通过淮北地区童亭、桃园、祁东等矿井开采实践,认为巨厚松散层下采煤煤岩柱的留设原则为:初期以防水为主,后期以防砂为主。      

巨厚松散层下防水煤柱合理留设及其数值模拟

防水煤柱合理留设是巨厚松散层下煤炭开采设计的基本参数。通过对东欢坨矿第四系巨厚松散层地质特征分析,揭示了本区第四系巨厚松散层中的含、隔水层厚度及其结构分布特征和对煤炭开采充水的影响,建立了巨厚松散含水层下防水安全煤柱计算模型和理论,提出了在巨厚松散层下的防水煤柱留设的非线性计算方法,计算东欢坨矿8煤层防水煤岩柱的高度为65.62 m。根据流-固耦合理论,应用FLAC3D数值模拟计算软件,模拟了东欢坨矿 8煤层开采过程中上覆岩层变形破坏规律,揭示了煤层顶板岩体冒落带、导水裂隙带和弯曲下沉带的分布规律,获得了防水煤柱高度及相关工程技术参数,验证了巨厚松散层下防水煤柱留设的非线性设计方法和计算模型的可靠性,为巨厚松散层下防水煤柱合理留设探索了可行途径。      

小槽煤重复采动条件下断层防水煤柱宽度的数值模拟研究

为了合理确定断层防水煤柱宽度,利用FLAC数值模拟技术,根据小槽煤(太原组12下煤和16煤)重复开采的条件,对断层煤柱宽度进行数值模拟。结果表明,上、下两层煤开采时,围岩应力、塑性区分布及其变化特征不同,所需的断层防水煤柱宽度变化较大,12下煤开采时断层防水煤柱宽度为20 m;16煤重复采动条件所需的煤柱宽度为50 m左右。重复采动条件的断层煤柱留设宽度模拟结果能形象地刻画断层受采动影响程度,指导性更强,比《煤矿防治水规定》中的计算方法更具有一定的优越性,更能有效指导矿井16煤的断层防治水工作。     

孙疃煤矿102采区防水煤岩柱留设技术研究

依据准北孙疃煤矿102采区资料,通过分析研究矿区第四系、基岩风化带及10煤层顶板水文地质及工程地质条件,利用规程计算、FLAC3D数值模计算以及临近许疃、桃园两矿的实测资料,最终得出采区的冒落带高度为14m,裂隙带高度为45.6m,从而确定该采区的防水煤岩柱为30m,并对其可靠性进行分析论证。该项研究可以使采区10煤层防水煤柱的留设从90m降低到30m,解放煤炭资源量42万t,产生直接经济效益10500万元。     

开采覆岩破坏工程地质力学模型实验研究

在对工程地质力学模型材料配比研究的基础上，以太平煤矿8301工作面近风化带开采为工程地质原型，建立了工程地质力学试验模型，模拟了不同开采方案的覆岩及松散层底部粘土层的变形破坏状况，为防水煤岩柱留设高度决策提供了依据。     

潘谢矿区水文地质特征与缩小防水煤柱机理

淮南潘谢矿区年总设计生产能力为 2 10 0× 10 4t。区内第四系松散层厚 16 9～ 437m ,为巨厚松散强含水层 ,设计留设80m防水煤岩柱 ,防水煤柱储量达 6× 10 8t。通过开展缩小防水煤柱试采研究工作 ,将原设计留设的 80m防水煤柱减小到6 0m左右 ,局部仅 40m。本文通过总结潘谢矿区 10年来缩小防水煤柱工作面成功的开采实践 ,比较系统地阐述了潘谢矿区水文地质特征、覆岩破坏规律及缩小防水煤柱机理。     

金乡矿区深厚土层工程地质特性初步研究

矿区深厚土层的工程地质性质对建井和开采有着重要的影响．本文根据金乡矿区详查阶段工程地质勘察成果，对厚松散层进行了工程地质层组划分，研究了各层组的矿物成分、物理性质、水理性质、力学性质和水文地质特征等在平面上和剖面上的变化规律，为该区的建井、防水煤岩柱留设和地表沉陷预计等提供依据。     

三维工程地质模型在防水煤岩柱留设研究中的应用展望

在第四纪厚松散含水层下采煤。留设防水煤岩柱是预防顶板水的有效方法。本文从该研究的现状及存在的问题出发,提出运用三维工程地质模型方法探讨导水裂隙带,含水层,保护层的三维形态,进而通过空间分析并结合生产实际确定合理的防水煤岩柱尺寸,实现水体下煤炭资源的充分开发。     

急倾斜煤柱开采后对巷道影响的数值模拟

为提高煤炭的回收率和经济效益,针对长沟峪煤矿4槽煤柱,应用ANSYS有限元软件对-230～-310水平的煤柱开采前后进行数值模拟,得出:(1)煤柱开采以后,煤岩体总体下沉,但对-140水平巷道影响较小。(2)开采后,煤柱的中间部位是转折区,煤柱中部以上主应力减小,属于安全区域;煤柱中部以下主应力增大,随深度的增加,主应力增大;-320水平附近煤柱采后的主应力是采前的2倍多,是煤柱开采后主应力最大的地方,所以开采此区域为相对重点注意区域。(3)煤柱开采后-140水平的煤柱附近主应力增大,是没开采前的1.6倍,也是煤柱开采后主应力较大的地方,开采前要适当对-140水平煤柱附近进行加固。数值模拟得出结果和实际开采吻合较好,因此急倾斜煤柱开采后对巷道影响的数值模拟对开采有一定的指导意义。     

榆神矿区保水采煤的工程地质背景

论述了榆神矿区煤层上覆红土、风化带基岩、未风化基岩的工程地质特征,认为红土层具有较好的隔水性能,风化带基岩中粘土矿物的含量增加,隔水性能明显增强。2-2煤层上覆基岩为中硬岩石,而且有较多的软弱岩石夹层,煤层开采的冒裂带发育高度相对较小,影响不到第四系萨拉乌苏组含水层底部,具有较好的保水采煤工程地质条件。      

大采高综放面区段煤柱合理留设研究

侧向支承压力分布、资源回收率以及煤柱和巷道的稳定性是大采高综放面区段煤柱宽度留设要兼顾的因素,为了确定大采高综放面区段煤柱宽度,以某矿8103面为工程背景,首先,采用理论计算和现场应力监测等方法确定大采高综放工作面倾向支承压力分布规律,得出应力降低区宽度约为8 m,原岩应力区为巷帮侧28 m外。其次,采用工程类比方法确定大采高综放工作面巷帮外侧煤体严重破裂区宽度约为4 m。最后,采用FLAC3D数值软件分析了下区段工作面回采时窄煤柱（6、8 m）和宽煤柱（28、30 m）的应力场、位移场及塑性区特征,获得不同煤柱宽度时巷道和煤柱力学特征。研究表明：当煤柱宽度6 m和8 m时,在采动支承压力下煤柱几乎无承载能力,且巷道变形量较大;当煤柱宽度28 m和30 m时,在采动支承压力下煤柱中央仍有一定的弹性核,煤柱保持稳定且巷道变形量较小。综合考虑资源回收、巷道稳定性、次生灾害控制等因素,确定大采高综放工作面区段煤柱宽度为28 m。     

Influence of Coal Extraction Operation on Shaft Lining Stability in Eastern Chinese Coal Mines

In order to find the relationship between the shaft lining stability and the coal extraction operation, a 3D numerical model of strata layers and shaft lining was established for simulating the influence of coal extraction operation on shaft lining. Certain factors including mining depth, safety pillar width, mining width and mining height were taken as the influence factors in the simulation. The results indicated that the coal extraction could lead to the initiation of the failure in the aquifer and rock layers. As the mining depth increases, the shear strain increment in aquifer becomes small. In this case, the distance between mining panel and aquifer should be larger than 220 m and the safety pillar width should not <70 m. The maximum principal stress in aquifer had a little relation to mining operations. The mining panel width should not exceed 50 m without any support.     

A study of surface subsidence and coal pillar safety for strip mining in a deep mine

Some villages and bridges are located on the ground surface of the working district no. 7 in the Wanglou Coal Mine. If longwall mining is adopted, the maximum deformation of the ground surface will exceed the safety value. Strip mining is employed for the working district no. 7 which is widely used to reduce surface subsidence and the consequent damage of buildings on the ground surface. To ensure the safety of coal pillars and improve the recovery coefficient, theoretical analysis and numerical simulation (FLAC 3D) were adopted to determine the coal pillar and mining widths and to discuss the coal pillar stress distribution and surface subsidence for different mining scenarios. The results revealed that the width of coal pillars should be larger than 162 m, and the optimized mining width varies from 150 to 260 m. As the coal seam is exploited, vertical stress is mainly applied on the coal pillar, inducing stress changes on its ribs. The coefficient of mining-induced stress varies from 2.02 to 2.62 for different mining scenarios. The maximum surface subsidence and horizontal movement increase as the mining width increases. However, when the mining width increases to a certain value, increasing the pillar width cannot significantly decrease the maximum subsidence. To ensure the surface subsidence less than 500 mm, the mining width should not be larger than 200 m. Considering the recovery coefficient and safety of the coal pillar, a pillar width of 165 m is suggested.     

Numerical Investigation of the Dynamic Mechanical State of a Coal Pillar During Longwall Mining Panel Extraction

This study presents a numerical investigation on the dynamic mechanical state of a coal pillar and the assessment of the coal bump risk during extraction using the longwall mining method. The present research indicates that there is an intact core, even when the peak pillar strength has been exceeded under uniaxial compression. This central portion of the coal pillar plays a significant role in its loading capacity. In this study, the intact core of the coal pillar is defined as an elastic core. Based on the geological conditions of a typical longwall panel from the Tangshan coal mine in the City of Tangshan, China, a numerical fast Lagrangian analysis of continua in three dimensions (FLAC^3D) model was created to understand the relationship between the volume of the elastic core in a coal pillar and the vertical stress, which is considered to be an important precursor to the development of a coal bump. The numerical results suggest that, the wider the coal pillar, the greater the volume of the elastic core. Therefore, a coal pillar with large width may form a large elastic core as the panel is mined, and the vertical stress is expected to be greater in magnitude. Because of the high stresses and the associated stored elastic energy, the risk of coal bumps in a coal pillar with large width is greater than for a coal pillar with small width. The results of the model also predict that the peak abutment stress occurs near the intersection between the mining face and the roadways at a distance of 7.5 m from the mining face. It is revealed that the bump-prone zones around the longwall panel are within 7–10 m ahead of the mining face and near the edge of the roadway during panel extraction.     

矿井初步设计中边界防隔水煤岩柱留设探讨

针对一些矿井初步设计中留设边界防隔水煤岩柱不合理而引发矿井老空水矿难的现实,探讨了影响矿井间边界防隔水煤岩柱安全稳定性的因素,提出应充分考虑煤岩柱受覆岩应力破坏变形、覆岩受采动影响产生岩移破坏等,综合分析计算煤柱有效稳定性弹性核区宽度、覆岩导水裂缝带上限岩柱宽度及其抗静水压能力等,择优选取留设矿井边界防隔水煤岩柱。以济宁煤田济宁二矿与三矿边界煤柱的留设为例,计算其边界煤柱留设尺寸为99.56m,较原设计的40m有较大出入,据此对两矿井边界隔离煤柱进行了相应调整,确保了矿井的安全生产。该方法也可用于矿井留设采区、区段隔离煤柱的计算。     

基于巨厚岩层-煤柱协同变形的煤柱稳定性

采前煤柱稳定性研究是工作面冲击危险性评估和开采方案设计的关键。以山东某矿深井巨厚砾岩条件工作面开采遗留煤柱为背景,采用案例调研、理论分析、数值模拟和工程实践等方法,对巨厚岩层-煤柱协同变形机制及其煤柱稳定性进行了研究,建立了巨厚岩层-煤柱协同变形的简化力学模型,探讨了引起煤柱变形的主要应力来源和变形形式,推导了在协同变形条件下煤柱的应力-应变关系。以此为基础,综合煤柱煤体应力、围岩稳定性和变形特征等条件,提出了煤柱整体失稳的力学判据。研究结果表明：巨厚岩层-煤柱失稳诱发冲击与煤柱的位置、尺寸和上覆岩层运动或变形关系密切,上覆岩层运动或变形是诱发煤柱失稳的动力因素;巨厚岩层-煤柱的变形主要包括受集中力F压迫的协同挠曲压缩变形和受集中力G作用的重力沉降变形,二者保持内在协调性;巨厚岩层下煤柱整体失稳的工程判据为煤柱煤体平均支承应力p超过其平均极限支承强度Rc（p≥Rc）;评估得到遗留的50 m煤柱具有强冲击危险性,并通过优化开采设计,取得了良好的效果。该研究成果对相似条件煤柱留设及其稳定性分析具有参考意义。     

平煤八矿己15-13030工作面煤层顶板突水溃砂可能性评价

煤矿突水溃砂灾害的发生与煤层上履含水层性质、岩性特征及破坏程度等诸多因素有关。通过研究己15煤层顶板基岩与第四系底部的含、隔水性能及顶板覆岩岩性组合特征,计算出一次全部开采3．6m煤层时,其导水裂缝带最小发育高度为38．46m,最大为47．95m,确定了采煤活动导致的上覆顶板含水层发生水力联系的范围,认为己15—13030工作面煤层开采时发生顶板突水的可能性不大;计算一次全部开采3．6m煤层时,防砂安全垂高最大为23．5m．防塌安全煤岩柱最大垂高为12．5m,结合煤层顶板基岩及第四系底部岩层的水文地质特征,认为工作面回采时顶板溃砂的可能性也不大。强调在生产过程中,要加强顶板涌水的观测,同时增加现有排水系统的排水能力,从而为工作面安全回采提供支持。     

Pressure-Relief Mining of the Working Face Under the Coal Pillar in the Close Distance Coal Seams

Intensive strata behaviors are generated when the No. 8707 working face of the 8# coal seam in a coal mine is advanced by way of the pillars left over of the upper part of 7# close distance coal seam. The theoretical analysis, numerical simulation and filed measurement were utilized to obtain the rule of the stress change when the 8707 working face of the 8# coal seam passes the pillars left over of the 7# coal seam. Meanwhile, a pressure-relief mining (PRM) technology was put forward. According to the research results, when the 8707 working face in the 8# coal seam was advanced to the position that was 20 m in front of the pillar left over, the abutment pressure reached the maximum for 26 MPa and the stress concentration factor was 3.25, which was likely to give rise to the rock burst. With the advance of the working face, the abutment pressure was reduced slowly. As the 8707 working face advanced 15 m away the pillar left over, the transfixed shear failure region of 45° was found in the bedrocks of the upper and lower coal seams, which was readily to give rise to the shear rupture, leading to the rock burst. Based on the aforementioned research, this research carried out the PRM by applying the hydraulic fracturing technology on the coal roof and pillar, which can ensure the safety and efficient mining of working faces.