低透高瓦斯煤层群安全开采关键技术研究

 针对低透高瓦斯煤层群安全高效开采技术难题,以淮南矿区为主要试验研究基地,研究应用岩石力学、岩层移动理论和“O”形圈理论,针对不同煤层和瓦斯地质条件,探索出一整套“开采煤层顶底板卸压瓦斯抽采工程技术方法”,建立卸压开采“抽采”瓦斯和煤与瓦斯共采工程技术体系。研究“采场岩层移动规律、卸压瓦斯运移规律、卸压瓦斯富集区、开采煤层卸压范围以及开采煤层增压范围”科学规律,研究“首采层卸压瓦斯、上向卸压层瓦斯、下向多重卸压层瓦斯以及地面钻孔卸压瓦斯”理论与技术,形成系统、成熟的瓦斯抽采理论与技术。创新卸压开采抽采瓦斯理论和技术,解决了煤与瓦斯共采重大工程技术难题。     

大采高综采工作面综合立体瓦斯治理技术研究与应用

袁店一井煤矿1033工作面具有煤层厚、采高大、本煤层及邻近层瓦斯含量高的特点,瓦斯治理难度较大。设计采用地面瓦斯井、上向拦截钻孔抽采上邻近层中组煤卸压瓦斯,采用高位钻孔、老塘埋管抽采采空区瓦斯,工作面最大抽采瓦斯纯流量为100.42 m3/min。在工作面回采期间,根据顶板周期来压规律预测瓦斯涌出量易增大时间段,重点加强瓦斯管理。     

伟峰煤矿6~#煤层瓦斯抽采技术研究

依据矿井在达产时瓦斯最大涌出量的预测,伟峰煤矿开采6#煤层时属于高瓦斯矿井。为了有效防范瓦斯事故并合理利用瓦斯资源,文章通过采用对本煤层预抽及边采边抽、邻近层高位钻孔抽采裂隙带、现采空区插管抽采和老采空区全密闭抽采的方法,从而达到煤与瓦斯安全高效共采的目的。     

大孔径顶板长钻孔瓦斯抽采技术的研究

针对潘三矿1311(3)采煤工作面的瓦斯涌出特性,为有效的治理瓦斯超限的难题并节约成本,采用φ89mm钻杆、ZDY-10000S系列钻机及配套钻具,成功施工了深度超过500m的走向抽采钻孔并以此代替传统的高抽巷瓦斯抽采技术。通过对大孔径顶板钻孔抽采瓦斯方法的抽采效果及经济效益的分析,表明利用大孔径钻孔顶板钻孔抽采瓦斯技术治理瓦斯效果是显著的,瓦斯抽采浓度达到50%以上,实现了采煤工作面安全高效回采。     

深孔爆破在综放开采坚硬顶煤预先弱化和瓦斯抽采中的应用

为解决坚硬特厚高瓦斯煤层采用综采放顶煤方法开采时,坚硬顶煤在矿山压力的作用下破坏不充分,从而造成煤炭资源的回采率低,同时使工作面呈现强烈的矿压显现和瓦斯浓度大而严重威胁工作面的安全等问题,提出深孔爆破顶煤预先弱化和瓦斯预抽技术。通过顺层钻孔煤层深孔爆破数值模拟和理论研究相结合的方法,揭示深孔爆破预裂顶煤和抽采卸压瓦斯机理。药柱在坚硬顶煤中爆破,爆破孔周边的煤体受爆轰应力波的作用产生裂隙并发生大幅度位移,使爆破孔周围的应力重新分布,厚层顶煤垮落;同时,在炮孔周围形成爆破松动破碎圈,瓦斯解吸沿着裂隙流动,提高瓦斯抽采效率。最后,在水帘洞煤矿3801工作面进行超前深孔爆破顶煤预先弱化和瓦斯抽采的现场应用,对类似条件下高瓦斯坚硬顶煤综放工作面特厚煤层开采具有很好的借鉴意义。     

底板岩巷穿层瓦斯抽采钻孔的优化布置

为了提高本煤层穿层钻孔的瓦斯抽采效果,采用COMSOL软件分别对阳泉矿区五矿8406工作面不同钻孔间距、钻孔直径、抽采负压条件下底板岩巷穿层钻孔的瓦斯抽采效果进行了数值模拟。结果表明:阳泉矿区五矿8406工作面穿层钻孔的合理布置间距为2~2.5m,并且钻孔间距对穿层钻孔的瓦斯抽采效果影响显著。研究结果为工程实践提供了理论参考依据。     

基于瓦斯抽放的顶板冒落规律模拟试验研究

为了给采空区瓦斯抽放高位长钻孔的设计提供依据，采用相似模拟试验与关键层理论分析采空区顶板产生裂隙、断裂、冒落和离层情况及其变化规律。随工作面的推进，关键层的弯曲变形经历从缓慢-剧烈-缓慢-破断的过程：亚关键层的弯曲下沉范围明显小于主关键层。关键层破断后，其下采空区两侧垫层的弹性变形得到恢复，下沉位移出现反弹。关键层的承载作用和岩层力学特性的差异使关键层间顶板的垮落角不同。覆岩关键层的破断使工作面顶板垮落角减小、周期垮落步距和来压强度都增大。依据覆岩关键层的破断形态、顶板的垮落角和周期来压（垮落）步距可以确定瓦斯抽放钻孔的终孔位置和钻场间钻孔的压茬距离，并预测钻孔的抽放瓦斯效果。     

冲击性顶板运动及其应力演化特征的3DEC 模拟研究

 采用三维离散元程序建立煤层综放开采模型，研究综放工作面推进过程中采场、采空区上覆顶板岩层的冲击性运动形式和分段性垮落形态，记录并且分析采场动态推进过程中，采动围岩中岩层块体垂直应力、水平应力的动态演化特征。研究结果表明，采空区基本顶的运动形式、来压周期、来压强度与直接顶的垮落厚度有关；支架后方的直接顶挤压成拱缓冲了基本顶的来压冲击强度，同时也改变了其来压步距。随着工作面向跟踪块体方向的推进，块体垂向应力、水平应力存在高低应力分区，并且不断地波动，岩层应力峰值位置随着岩层高度的增加稍向煤壁前方移动。     

三维应力条件下煤层底板采动破坏规律实验研究

以川煤集团白胶煤矿2481工作面地质资料为基础,利用自行研制的“多场耦合煤矿动力灾害大型模拟试验系统”,进行了三维采动应力条件下的三维模拟开采实验。通过应力监测、测量统计、色素示踪、照相素描等方法,对采动后的底板岩层破坏规律进行了研究。研究结果表明:底板岩层表现出“采前增压-采后卸压-压实回升”的动态受力特征;根据裂隙发育特征,可将底板裂隙带在走向上分为“开切眼裂隙发育区”、“采空区中部压实区”和“工作面裂隙发育区”,在竖直方向上分为“底板破断裂隙带”和“底板弯曲离层带”;确定底板最大破坏深度为14 m,为上保护层开采中被保护煤层瓦斯抽采的设计及优化提供了依据。     

大直径深孔钻进技术的应用

随着矿井往下延伸开采,瓦斯涌出量越来越大,瓦斯治理成为了开采的一大难题.一般的抽采方法无法达到工作面瓦斯治理的需要,从经济、安全、效果来考虑工作面的瓦斯治理.本文介绍了大直径深孔钻进在工作面的瓦斯治理应用,并总结了其在瓦斯治理方面的可行性.     

长壁工作面采空区见方形成异常来压的微震监测研究

上覆岩层的断裂失稳下沉是造成工作面矿压显现的根源。采用微震监测技术对长壁工作面见方期间围岩破坏的整个过程进行监测,研究长壁工作面见方期间微震事件动态信息与岩层运动及矿压显现间的关系,揭示大能量微震事件发生和工作面围岩异常矿压的物理力学机制。同时,统计研究采场煤壁片帮和支架工作阻力的动态变化规律。微震监测与宏观矿压观测综合对比研究表明,见方期间的开采影响范围比正常开采时大,围岩释放能量也达到极大值。研究结果证实了采空区见方期间工作面将发生异常矿压,能够为见方期间冲击地压、煤与瓦斯突出和底板突水等矿井动力灾害防治提供针对性的指导。     

Hydraulic conductivity changes and influencing factors in longwall overburden determined by slug tests in gob gas ventholes

This study presents the results of core-log analyses from the exploration boreholes, the analyses of face advance rates, and the results of downhole monitoring studies performed in gob gas ventholes for calculation of changes in hydraulic properties in the longwall overburden at a mine site in southwestern (SW) Pennsylvania section of Northern Appalachian Basin. In the first part of the study, coal measure rocks in overburden strata were analyzed and the locations where possible fractures and bedding plane separations would occur were evaluated. In the second part, the hydraulic conductivities were computed by two different slug test analyses methods using the water level changes measured in gob gas ventholes as longwall face approached. Hydraulic conductivities were analyzed with respect to the changes in overburden depth, the locations of the borehole, and mine face advance rates. These data were used to interpret the potential productivities of the gob gas ventholes as a result of fracturing and changes in hydraulic conductivities.The general results showed that the probability of fracturing and bedding plane separations in the overburden increase between strong and weak rock interfaces. Also, the probability of bedding plane separations increases as the interface is close to the extracted coal seam. Evaluation of slug tests showed that the hydraulic conductivity developments in the boreholes and their potential production performances are affected by the underground strata and the roof materials. In situations where the roof material is stiff and thick, the development of high permeability fractures around the borehole will be less. Results also indicated that borehole location with respect to face position affects the fracturing time and permeability evolution as well. Greater overburden depths generally cause earlier fracturing as longwall face approaches, but eventually result in lower hydraulic conductivities and potentially less effective boreholes. Increasing mining rates also resulted in generally lower hydraulic conductivities in the overburden. The results of this study were intended to improve the interpretation of gob gas venthole performance and to provide better siting of these boreholes.     

High quality and cost effective drilling system for prebored pressuremeter testing

A prebored pressuremeter test (PMT) requires a predrilled vertical smooth surface borehole of a constant diameter. Two methods for the preparation of predrilled boreholes are included in ASTM D4719. The first method is drilling a borehole using a rotary rig. While this method provides a constant diameter and a vertical borehole, it is costly and time consuming. The second method is the drilling of a borehole by a hand auger (Iwan type). While this is a low cost, rapid method, it may not provide a vertical borehole of constant diameter in a variety of soils.An innovative mechanical drilling system (MDS) has been developed for the preparation of vertical smooth surface borehole of constant diameter for the pressuremeter testing. The PMT was conducted in boreholes drilled by MDS, rotary rig (RR) and hand auger (HA) at a site that comprised clayey silt (CL-ML) and sandy silt (ML) deposits. The PMT curves thus obtained were compared in terms of quality, cost and time. The comparison indicates that good quality and cost effective PMT curves can be obtained by using MDS in broader strain range (up to 40%) for the stiffness and limit pressure determination.     

冲击钻钻速与隧道岩石力学参数的关系探讨

超前冲击钻钻探是岩石隧道中一种轻便、快捷、成本较低的直接地质预报方法,通过钻进数据可以判断掌子面前方地层的状况,降低地质事故的发生率.目前在地质钻预报方面主要是通过不在同一平面的三个钻孔来预测地层空间位置,对于地层性质的预测通常是定性的.作者以一种钻机为基础,进行了大量的现场实测,根据现场实测数据、实验室测试数据、现场的地质描述,分析了冲击钻钻速与岩石抗压强度、围岩类别的定量关系,建立了钻速与岩石BQ的统计关系式,这为隧道变更设计,预防事故提供了坚实的数据基础.     

Voussoir beam model for lower strong roof strata movement in longwall mining - Case study

The paper presents the influence of varying immediate roof thickness on the lower strong roof strata movement and failure pattern in longwall coal mining with large mining height. The investigation is based on 58 geological drill holes and hydraulic shield pressure measurements around the longwall Panel 42105 of the Buertai Mine in Inner Mongolia Autonomous Region, China. The longwall Panel 42105 is characterized by relatively soft immediate roof strata of varying thickness superposed by strong strata,herein defined as lower strong roof. A voussoir beam model is adopted to interpret the structural movement of the lower strong roof strata and shield pressure measurements. It is shown that when the immediate roof is relatively thick, the broken overlying lower strong roof tends to form a stable voussoir beam with previously broken layer, thus not exerting high pressure on the hydraulic shield and working face. When the immediate roof is relatively thin, the broken overlying lower strong roof tends to behave as a cantilever beam, thus exerting higher pressure on the hydraulic shield and working face. Comparison of model predictions with measured time-weighted average shield pressure(TWAP) shows good agreement.     

Influence of geotechnical factors on gas flow experienced in a UK longwall coal mine panel

Methane drainage has become an integral part of modern coal mining operations when gas emissions cannot be practically dealt with using conventional ventilation methods alone. Boreholes are often drilled above and below the caving zone and connected to a drainage range located along the return gate. This paper describes the construction and analysis of the results obtained from the two- and three- dimensional geomechanical and gas flow models experienced around an active deep UK longwall coal production panel. The models constructed using the commercial FLAC codes were undertaken to provide information to the ventilation engineers at the mine on the likely gas sources and gas flow paths into the face line areas and gate roads. This information allows for the correct design of the orientation, length and support of the boreholes to maximise gas capture. The paper describes the method adopted to derive the relevant rock mass parameters and the laboratory tests conducted to obtain the stress-dependent permeability of coal measure rock strata. A functional relationship is proposed whereby the intrinsic bulk permeability of a sheared coal measure rock may be predicted from the confining stress. A detailed discussion of the geomechanical modelling methodology and the derivation of the strata permeabilities and gas flow modelling adopted is presented. The output of the models is described and used to interpret the major potential gas sources and pathway into the workings.     

岩层移动的组合岩梁理论及其应用研究

提出了采场上覆岩层移动的组合岩梁模型，将岩层移动的关键层、岩层组合以及层间离层统一在组合岩梁模型的体系中，建立了关键层、岩层组合以及层间离层的统一判别准则，并进行了实例分析。对组合岩梁模型在岩层移动规律研究、地表沉陷控制以及在矿井瓦斯防治中的应用进行了深入地分析。组合岩梁模型的建立，为采场矿压和岩层移动的研究提供了一种新的思想和方法。     

地面钻孔并行三维电法探测煤矿灰岩导水通道

 提出利用地面钻孔并行三维电法探测煤矿灰岩导水通道,为煤矿灰岩水害防治提供新的物探手段。该方法在地面需布置3个钻孔,在各孔中置入一条电极电缆,电法测线需控制探测目标地层。将3钻孔电极电缆连成统一观测系统,利用并行电法仪采集AM法数据。将孔中各电极统一编辑坐标,对AM法数据进行三维电阻率层析成像,可得到3钻孔间三维电阻率变化情况。根据富水区与正常岩层间的电性差异情况,分析富水区可能的电阻率表现形式,再结合已有钻孔地层柱状、巷道涌水以及注浆资料等,得到灰岩地层中含水区及导水通道范围。将此方法应用于淮南矿业谢桥矿的探测,结果表明：该方法较准确地查明突水区灰岩地层导水通道,能很好地指导灰岩段注浆堵水工作,使得东风井车场涌水量大大减小,消除灰岩突水威胁。     

Sanierung der Drainage- und Kontrollbohrungen im Untergrund der Sorpetalsperre

Remediation of the underground drainage and control system of the Sorpe dam To ensure the structural stability of the Sorpe dam, the Ruhrverband is remediating the no longer fully functional underground drainage and control system. Built between 1926 and 1935, the 69 m high rockfill dam with a concrete core seal was damaged during the Second World War, which led to increased seepage water in the inspection gallery. In the 1950s the original drainage system was therefore grouted and a new system created. In the 2010s it was discovered that the boreholes in the bedrock were no longer at their original depth due to sediments containing iron and manganese. In the current remediation the existing drainage and monitoring boreholes are either being widened by drilling or filled with cement suspension and replaced with new borehole profiles. All boreholes will then be converted into measuring points for monitoring the water level, seepage water and pressure. The drilling work poses a particular challenge due to the limited space within the dam structure. In July 2022 the remediation work was temporarily halted due to the occurrence of chemical injection agents containing PAHs. The work is expected to continue in the first quarter of 2024 using strict separation of clean and contaminated areas with artificial ventilation as well as a flocculation and activated carbon filter system for the drilling fluid.     

全回转清障工艺在复杂环境条件下深基坑施工中的应用

介绍了上海世博北京西路～华夏西路电力电缆隧道工程的5^#工作井地下连续墙施工中,针对施工周边环境复杂、重大风险源较多和地下深层障碍物位置不明确的情况,选用了气动钻机进行探孔灌浆,以及钢套管钻进法的全回转钻机进行深层障碍物清除,既保证了障碍物区域地下连续墙的顺利完成,又保护了临近密集的地下管线和加油站,同时保证了盾构顺利进洞。