深井软岩巷道底板卸压钢丝绳网锚注支护技术研究

针对平顶山天安煤业股份有限公司一矿深井软岩回风上山巷道工程地质条件和围岩变形特征,采用数值计算方法,研究了底板卸压槽卸压前后巷道围岩应力场、塑性区的变化规律,分析了底板卸压槽卸压机理,提出了钢丝绳网锚注支护技术,并进行了工业性试验。研究结果表明:(1)巷道底板开掘卸压槽卸压后,底板围岩垂直应力和水平应力的高应力区及其峰值应力均向底板深部转移。卸压后底板同一深度的围岩应力均小于卸压前的围岩应力;卸压后巷道顶底板和两帮围岩的塑性区范围均增大,底板卸压效果明显。(2)深井巷道围岩的破碎区和部分塑性区是支护的重点。回风上山巷道采取开挖底板卸压槽、钢丝绳网锚杆支护和围岩注浆加固等支护措施后,在围岩中形成了锚注体支护圈,提高了围岩的强度和自身承载能力。巷道围岩经历加速变形阶段、减速变形阶段和稳定变形阶段后,一直处于稳定变形状态。卸压槽+钢丝绳网锚注支护在回风上山巷道的支护试验取得成功,可为深井软岩巷道支护提供参考依据。     

浅埋深工作面冲击地压切顶卸压效果监测分析

为检验宽沟煤矿浅埋深工作面采用切顶卸压的措施治理冲击地压的效果,采用钻屑、电磁辐射仪、微震监测、PASAT-M便携式微震等4种监测检验手段对W1143工作面全断面切顶卸压治理冲击地压效果进行检验.结果表明,4种监测手段检验结果一致,全断面切顶能够改变顶板应力重新分布及有效地防止工作面冲击地压事故的发生,能够最大限度地缓解和消除冲击地压危害.     

深埋薄基岩综放工作面切顶卸压沿空留巷围岩协同控制技术研究

为解决深埋薄基岩切顶卸压沿空留巷巷道受采动影响支护困难的问题,以焦作煤业集团赵固(新乡)能源有限责任公司赵固一矿18060综放工作面切顶卸压沿空留巷巷道为工程背景,基于留巷围岩结构运动和覆岩力学传递特征,提出深埋薄基岩切顶卸压沿空留巷巷道围岩协同控制技术。研究结果表明:采用定向预裂爆破技术能够切断留巷顶板下位关键岩层,并形成短壁梁结构;与未切顶相比,切顶后巷道侧向支承压力减小14.17 MPa(降低37.67%),顶板竖向应力峰值减小5.22 MPa(降低22.5%);切顶侧矿压较未切顶侧明显降低,切顶影响范围约30 m;留巷两帮收缩量最大为471 mm,顶底板移近量最大为717 mm,工作面后方约200 m开始稳定。提出的深埋薄基岩切顶卸压沿空留巷围岩协同控制技术现场应用效果较好,可为类似地质条件下的切顶卸压沿空留提供参考。     

“三软”煤层回采巷道钻孔卸压参数研究

回采巷道围岩控制一直是"三软"煤层开采高产高效的制约因素之一.根据永华一矿的地质条件,针对传统支护方式无法解决"三软"煤层回采巷道支护的难题,采用理论分析、现场试验的方法,提出了钻孔卸压与U型钢支架耦合支护技术.即通过在巷道U型钢支架之间打卸压钻孔,为巷道围岩变形留设变形空间,降低围岩应力,达到巷道稳定的目的.试验表明,U型钢支架耦合支护和钻孔卸压能够有效地控制巷道围岩变形,支护效果良好,为"三软"煤层回采巷道围岩控制提供了实践和理论依据.     

直接顶厚度对回采巷道稳定性影响的数值模拟研究

当回采巷道沿煤层顶板或底板布置时,由于煤层一般较顶底板软弱,因此,巷道围岩的矿压显现特征主要表现为两帮煤体的变形、破坏等现象,巷道易发生两帮煤体沿层理向巷道空间挤出的现象,并进而产生破碎、松动等现象.这与巷道上覆岩层的应力有着密切的关系.本文运用RFPA软件,分析了回采巷道上覆软弱直接顶厚度对巷道稳定性、巷道围岩应力分布与破坏情况、巷道围岩破裂部位与破裂范围的影响.通过对不同直接顶厚度影响下的巷道围岩稳定性分析,得出直接顶厚度与巷道围岩稳定性之间的数值关系,并分析了直接顶厚度对回采巷道稳定性的影响因素,这为煤矿回采巷道的开挖与支护提供一定的理论基础.     

直接顶厚度对回采巷道稳定性影响的数值模拟研究

当回采巷道沿煤层顶板或底板布置时,由于煤层一般较顶底板软弱,因此,巷道围岩的矿压显现特征主要表现为两帮煤体的变形、破坏等现象,巷道易发生两帮煤体沿层理向巷道空间挤出的现象,并进而产生破碎、松动等现象.这与巷道上覆岩层的应力有着密切的关系.本文运用RFPA软件,分析了回采巷道上覆软弱直接顶厚度对巷道稳定性、巷道围岩应力分布与破坏情况、巷道围岩破裂部位与破裂范围的影响.通过对不同直接顶厚度影响下的巷道围岩稳定性分析,得出直接顶厚度与巷道围岩稳定性之间的数值关系,并分析了直接顶厚度对回采巷道稳定性的影响因素,这为煤矿回采巷道的开挖与支护提供一定的理论基础.     

近直立特厚煤层应力调控防冲方法及机制

近直立特厚煤层的地质与开采条件与一般煤层差异较大,冲击地压防治形势严峻.本文综合采用理论分析、数值模拟、现场监测等方法,研究了近直立特厚煤层动静载力源分布特征,提出了应力调控防冲方法,揭示了其防冲机制,并进行了工程应用.结果表明：近直立特厚煤层主要受水平构造应力作用,水平应力通过工作面两侧的顶底板岩层传递至煤层中,并在巷道上下方形成静载集中区;近直立特厚煤层顶底板岩层难以发生破断,然而顶底板岩层破裂释放能量可形成强动载扰动;动载扰动作用于巷道上下方静载集中区并与集中静载叠加可诱发冲击地压.据此,提出了弱化工作面两侧顶底板岩层和下方煤体的应力调控防冲方法,其防冲机制为：弱化顶底板一方面可弱化岩体传递水平应力的能力进而降低巷道上下方的静载集中,另一方面可降低岩体静载集中进而减弱岩体破裂导致的动载强度;弱化煤体可进一步降低巷道下方静载集中并将静载集中区向深部转移.对近直立特厚煤层现场实施的防冲措施进行了优化设计并确定了关键参数,应用表明,工作面高能级微震事件减少了143～178起、微震事件总能量降幅达90%,未发生冲击显现,工作面冲击危险性显著降低,证实了方法的有效性.研究成果可为近直立特厚...     

深部巷道底板开槽卸压数值模拟分析

以登封市告成矿南翼副井深部水平轨道运输大巷发生严重底鼓问题为工程背景,采用底板开卸压槽的方案,转移巷道附近的高应力至更深部的岩体中,以此达到卸压的目的。利用FLAC3D数值模拟软件对卸压槽不同深度与宽度进行模拟,对中巷道周围塑性区面积、水平应力变化以及最大底鼓量综合分析。结果表明:过小的宽度与深度卸压效果不明显,过大的宽度与深度反而会削弱自身的卸压效果;当卸压槽深度为75.0%巷道高度、宽度为6.0%巷道宽度时,高水平应力场向围岩深部转移,最大底鼓量明显减少,综合卸压效果最好。     

N-J水电站岩爆区卸压技术的能量耗散率分析

为研究岩爆区卸压技术的能量耗散率,对巴基斯坦N-J水电站引水隧洞TBM施工的岩爆区进行钻孔卸压和爆破卸压分析,主要对108 mm直径钻孔的卸压应力释放、预裂爆破等情况进行数值模拟,模拟钻孔间距分别为0.5、1.0、1.5、2.0、2.5 m时的孔内钻孔卸压和预裂爆破情况。分析结果表明:预裂爆破卸压法的能量耗散率最高可达到27%,而单纯的钻孔卸压法的能量耗散率最大仅为5.9%,因此预裂爆破卸压的卸压效果远好于单纯的钻孔卸压方法的卸压效果;对于预裂爆破法来说,能量耗散率随卸压孔间距的增加而增大,基本呈指数型增长趋势,对于单纯的钻孔卸压法来说,能量耗散率随卸压孔间距的增加而减小,因此在生产现场应根据不同卸压方法布置合理的钻孔间距。     

沿空掘巷卸压支护技术研究

根据凤凰山煤矿现场实际情况 ,在矿压观测的基础上 ,分析了沿空巷围岩变形及支架载荷特征 ,结合卸压支护的维护原则 ,阐述了围岩蠕变卸压支护方式的原理 ,成功地在2 32 2工作面回风巷进行沿空掘巷卸压支护 ,实现了该巷道在服务期限内无维修 ,节约了维护费用 ,减少了优质煤炭资源的损失 ,提高了煤炭资源回采率和矿井的经济效益 .该种支护方式工艺简单、费用低、便于推广 .     

Floor heave in the west wing track haulage roadway of the Tingnan Coal Mine: Mechanism and control

Floor heave of a roadway is a dynamic phenomenon that often happens in the roadways of coal mines. It seriously affects safe production in the coal mine. Floor heave has long been one of the most difficult problems to be resolved during coal mining. An analysis of floor heave in the soft rock surrounding the roadway, and the factors influencing it, allowed the deformation mechanism in the west wing double track haulage roadway of the Tingnan Coal Mine to be deduced. Three types of floor heave are observed there: intumescent floor heave, extrusion and mobility floor heave, and compound floor heave. Control measures are proposed that have been adopted during a recent repair engineering project. Control of the floor heave in the west wing track haulage roadway was demonstrated. The reliability and rationality of a combined support technology including floor anchors, an inverted arch, and anchoring of both sides was verified by mine pressure data and the field observations. Waterproofing measures were also undertaken to assist in the control of floor heave.     

Support technology for mine roadways in extreme weakly cemented strata and its application简

For the engineering geology conditions of bad mine roadway roof and floor lithology in extremely weak cemented strata, the best section shape of the roadway is determined from the study of tunnel surrounding rock displacement, plastic zone and stress distribution in rectangular, circle arch and arch wall sections, respectively. Based on the mining depth and thickness of the coal seam, roadway support technology solutions with different buried depth and thickness of coal seam are proposed. Support schemes are amended and optimized in time through monitoring data of the deformation of roadway, roof separation, I-beam bracket, bolt and anchor cable force to ensure the long-term stability and security of the roadway surrounding rock and support structure. The monitoring results show that mine roadway support schemes for different buried depth and section can be adapted to the characteristics of ground pressure and deformation of the surrounding rock in different depth well, effectively control the roadway surrounding rock deformation and the floor heave and guarantee the safety of construction and basic stability of surrounding rock and support structure.     

构造应力区巷道变形破坏特征及控制技术研究

水平构造应力对巷道围岩稳定有重要的影响,针对鹤壁九矿东总回风巷在锚网索喷＋u型钢支护难以保证巷道稳定的情况,通过相似材料模拟试验研究不同水平应力作用下锚注支护巷道围岩变形破坏和位移变化特征．试验表明,随着水平应力的增大,底板加强后,水平应力对顶板的作用明显,当水平载荷达到49MPa时有少量浆皮脱落,左肩部出现块状冒落,底板比较稳定,没有发生明显臌起,只出现少量横向裂隙,锚注支护结构能控制围岩变形．将试验结果在现场应用后,通过矿压观测,两帮的最大移近量为144mm,顶底板最大移近量为105mm,锚注支护提高了围岩的自承能力,能够维持巷道稳定,为类似地质条件下的巷道支护提供借鉴．     

Effect of faulting on coal burst——A numerical modelling study

Coal burst occurrence on roadways has always been a major concern in deep underground coal mines,especially under complex geological conditions. To evaluate the effect of faulting on coal burst, the stress concentration in the vicinity a reverse fault was analysed considering the geological history of the fault formation where high horizontal stresses led to the initiation and propagation of the reverse fault.Various in situ stresses and mechanical parameters of the fault, including the ratio of horizontal stress to vertical stress were used to analyse the state of fault. Numerical modelling was conducted using two and three dimensional distinct element models(UDEC and 3 DEC) based on a geotechnical conditions of an Australian underground coal mine. The formation process of reverse fault was simulated to evaluate the stress characteristics in the coal seam and the immediate roof and floor near the fault. The results show that, both the horizontal and vertical stress in footwall were higher than those in hanging wall after the formation of the reverse fault. The stress condition near fault was complicated due to complex geology in the coal measures, and the vertical stress peaked in the footwall at a distance of about 160 m from the fault. When a roadway was excavated, stress concentration occurred at both the roadway face and ribs, which reached as high as 38 MPa in the ribs at a depth of 500 m. This will significantly elevate the risk of dynamic instability of the roadway such as coal burst. The stress concentration zone in the footwall can be considered as a hazardous zone near the reverse fault. This study provides a general reference for analysis of roadway stability affected by faults.     

古汉山煤矿软岩巷道底臌原因分析及防治措施

通过对处于软弱破碎带及构造应力集中区之中的古汉山煤矿井底车场巷道的长期观测研究 ,提出了软岩巷道底臌的形式 ,并结合该矿实际情况 ,分析了底臌形成的原因 ,提出了防治底臌的措施 ,有效地解决了巷道中底臌事故 .     

Numerical simulation study on hard-thick roof inducing rock burst in coal mine

In order to reveal the dynamic process of hard-thick roof inducing rock burst, one of the most common and strongest dynamic disasters in coal mine, the numerical simulation is conducted to study the dynamic loading effect of roof vibration on roadway surrounding rocks as well as the impact on stability. The results show that, on one hand, hard-thick roof will result in high stress concentration on mining surrounding rocks; on the other hand, the breaking of hard-thick roof will lead to mining seismicity, causing dynamic loading effect on coal and rock mass. High stress concentration and dynamic loading combination reaches to the mechanical conditions for the occurrence of rock burst, which will induce rock burst. The mining induced seismic events occurring in the roof breaking act on the mining surrounding rocks in the form of stress wave. The stress wave then has a reflection on the free surface of roadway and the tensile stress will be generated around the free surface. Horizontal vibration of roadway surrounding particles will cause instant changes of horizontal stress of roadway surrounding rocks; the horizontal displacement is directly related to the horizontal stress but is not significantly correlated with the vertical stress; the increase of horizontal stress of roadway near surface surrounding rocks and the release of elastic deformation energy of deep surrounding coal and rock mass are immanent causes that lead to the impact instability of roadway surrounding rocks. The most significant measures for rock burst prevention are controlling of horizontal stress and vibration strength.     

Numerical simulation research on dynamical variation of permeability of coal around roadway based on gas-solid coupling model for gassy coal

Due to the change of initial stress state caused by roadway excavation, the permeability of the coal body may be changed during the excavation process. In this paper, according to the different stress states, the coal around the roadway was divided into the seepage open zone, seepage orientation zone, seepage decay zone and original seepage zone along the radial direction of the roadway. The loaded gassy coal was treated as a viscoelastic and plastic softened medium, and the mechanical behaviors of the viscoelastic zone, plastic softened zone and broken zone around the roadway were analyzed with the consideration of the loading creep, softening and expansion effect of the gassy coal. According to the law of conservation of mass and the Darcy law, the flow-solid coupled model for the gas transportation of the coal around the roadway was established considering the dynamic evolution of the adsorption characteristics, porosity and permeability of the coal, and the simulation software COMSOL was utilized to numerically simulate the stress state and gas flow regularity around the coal, which provided meaningful reference for investigating the stability of the coal and rock around the roadway.     

综放面底板采动应力场的矿压显现规律

综采放顶煤开采一次采出厚度与覆岩运动范围成倍增加,采动应力大．以井下实测资料为依据,研究了综放面底板采动应力场对跨采巷道的作用,揭示了综放面底板采动应力场的基本特征及其跨采巷道矿山压力显现规律．     

Control mechanism and technique of floor heave with reinforcing solid coal side and floor corner in gob-side coal entry retaining

Floor heave is the most common convergence in gob-side entry retaining. The paper analyzes the form, process and characteristics of gob-side entry retaining with the comprehensive methods of theoretical analysis, numerical simulation and the field trial. Research results present that bending and folding floor heave is the main factor in the stage of the first panel mining; squeezing and fluidity floor heave plays a great role in the stable stage of gob-side entry retaining; the combination of the former two factors affects mainly the stage of the second mining ahead; abutment pressure is a fundamental contribution to the serious floor heave of gob-side entry retaining, and sides corners of solid coal body are key part in the case of floor heave controlling of gob-side entry retaining. Floor heave of gob-side entry retaining can be significantly controlled by reinforcing sides and corners of solid coal body, and influence rules on the floor heave of gob side entry retaining of sides supporting strength and the bottom bolt orientation in solid coal side are obtained. Research results have been successfully applied in gob-side entry retaining of G20-F23070 face haulage roadway in #2 coal mine of Pingmei Group, and the field observation shows that the proposed technique is an effective way in controlling the floor heave of gob-side entry retaining.