安装参数与掘进参数对滚刀破岩阻力的影响

为获得不同切削顺序下盘形滚刀安装参数与掘进参数对其破岩阻力的影响,通过建立多滚刀破岩数值模型,研究不同切削顺序下滚刀贯入度、刀间距、安装半径与刀盘转速等参数对滚刀破岩阻力的影响规律,采用多因素正交实验法分析各因素对破岩阻力的影响显著性,并通过滚刀破岩试验验证数值分析结果的正确性.研究结果表明：滚刀破岩阻力总体上随贯入度、切削速度、刀间距与安装半径的增加而增大;不同切削顺序下,滚刀破岩阻力各不相同,其差异性随贯入度增加以及刀间距减小而逐渐增大;3种不同切削顺序下,贯入度对滚刀破岩阻力影响均为非常显著,刀盘转速和滚刀安装半径对破岩阻力影响较小,刀间距对破岩阻力的影响随切削顺序变化而有明显差异,破岩试验结果与仿真基本一致.     

近浅埋大采高工作面关键层破断规律研究

以三道沟煤矿大采高综采工作面地质条件为原型,进行了相似材料物理模型实验研究.通过百分表、全站仪以及底板压力传感器构建实验的覆岩移动的监测系统和方法.结果表明:主关键层破断距与亚关键层破断距不成整数倍关系时,主关键层破断前,采场矿压显现较为平均,相邻周期来压间动载系数基本在1.40左右;主关键层破断后,由于主、亚关键层周期性协同破断的影响,矿压显现呈现大小交替变化,且来压步距与矿压显现强度呈现相反的规律,具体表现为:大周期来压时动载系数平均为1.61,来压步距集中在12~20 m;小周期来压时动载系数平均为1.39,来压步距集中在20~28m.     

下承式拱桥吊杆的破损安全研究

为研究吊杆破断对下承式拱桥静力响应的影响以及是否是破损安全的。以新建铁路马道口下承式拱桥为背景,采用桥梁专业软件MIDAS/CIVIL,运用准静力法对吊杆破断进行模拟。分析计算了单根吊杆破断和多根吊杆破断对桥梁结构的影响。结果表明:单根吊杆破断对下承式系杆拱桥静力响应影响较小,吊杆破断是破损安全的;当有连续的3对吊杆破断时,其相邻吊杆的安全系数严重降低,应力幅增量很大,会引起吊杆的连锁破断,对桥梁结构造成严重的损伤。     

采场上覆岩层平衡条件的模型研究

本文主要在实验室,用砌块模型的方法对采场上覆坚硬岩层已破断岩块的平衡及失稳条件进行了研究。由破断岩块形成的砌体梁可能出现三种失稳。并研究了三种失稳与砌体梁的跨距、高度及其承受载荷的关系。     

离层注浆控制冲击矿压危险机理探讨

煤层上覆坚硬厚层岩层组成的主关键层对冲击矿压的发生具有强烈的影响,主关键层岩层的剧烈活动是冲击矿压发生的集中区域,而且震级也高;冲击矿压的发生需要煤层及其周围岩层中聚集大量的弹性能外,还需要主关键层破裂等释放的外部能量;该外部能量与岩层厚度的平方、抗拉强度的2．5次方成正比;破断中心距巷道工作面越近、释放的能量越大,传播到巷道工作面处的能量越大,越容易引发冲击矿压。因此,可采用覆岩离层注浆等技术手段保证覆岩主关键层的长期稳定,消除主关键层岩层破断引发的冲击矿压危险。     

基于FLAC~(3D)对含软硬岩互层边坡的变形分析

以南京地区采矿形成的边坡为背景,研究含有硬岩的软硬岩互层边坡的稳定性。运用FLAC~(3D)基于有限元强度折减法,模拟不同硬岩岩层的倾角和厚度对顺向坡和反向坡变形的影响,分析对比上述因素对边坡变形影响的大小。研究结果表明,顺向坡中硬岩的倾角越大,厚度越大,变形越小,并且变形有趋于稳定的趋势;反向坡中硬岩的倾角越大,厚度越大,变形先减小后增大,说明上述因素越大,反向坡越容易产生倾倒变形。     

自锚式悬索桥断索动力冲击效应模型试验研究

为探讨自锚式悬索桥在吊索瞬时破断作用下的动力冲击效应,以某在役自锚式悬索桥为背景,基于刚度相似理论建立1：80的缩尺试验模型,进行不同区段内吊索的断索动力冲击效应模型试验。试验结果表明：不同区段吊索破断引起的冲击效应不同;断索会引起与破断吊索同侧同跨的相邻吊索区域内的动态内力重分布且动力冲击效应明显;与瞬断吊索紧邻的两根吊索中,较长吊索的动力冲击系数（DIF）和动力放大系数（DAF）均较大,其动力冲击效应和冲击作用敏感性更高;瞬断工况下的吊索拉力动态响应峰值较断索前普遍达到2倍以上,吊索的安全储备明显较低。相邻吊索在断索作用下的动力冲击效应显著,若相邻吊索存在腐蚀等缺陷,极易导致桥梁连续性断索,严重影响桥梁安全。     

牙轮钻头喷嘴射流破岩机理研究

本文以喷嘴射流冲蚀岩石为依据，对牙轮钻头的破岩方式、喷嘴射流的水力破岩和水力辅助破岩机理以及破岩的基本作用和影响因素进行了分析研究。结果表明，在现有机泵条件下牙轮钻头喷嘴射流对泥岩、页岩和粗粒砂岩具有直接水力破岩作用，对石灰岩、细粒砂岩有较好的水力辅助破岩作用。喷嘴射流冲击压力、射流的脉动特性、岩石的孔隙度和裂缝发育条件是影响水力破岩和水力辅助破岩的三个重要因素     

顶板隔水层关键层耦合作用规律研究

在煤矿开采过程中，如果覆岩裂隙扩展至贯穿隔水层，则会诱发地下水或地表水大量涌向采场，导致煤矿淹井事故．利用RFPA^2D-Flow软件建立了隔水层关键层耦合的采场推进模型，计算并分析了裂隙场的发育和分布，绘制了顶板水渗流量曲线．讨论了与裂隙发育密切相关的覆岩支承压力与中间岩层厚度、关键层厚度及破断闻的关系．结果表明：关键层未破断时，中问岩层厚度对隔水层裂隙发育作用不明显；厚关键层对隔水层能起较好的保护作用．     

巨厚煤层顶板离层水致灾机理研究

为探讨巨厚煤层顶板离层水的致灾机理,以陕西焦坪矿区某矿1418工作面为研究对象,分析其突水特征及突水地质条件,并基于"拱梁平衡理论",对可致灾离层发育层位进行了判别,对离层水发育的周期进行了计算,采用UDEC数值模拟软件,对覆岩离层及导水裂缝带的发育过程进行了模拟。结果表明:可致灾的"空腔型"离层发育在直罗组泥岩和宜君组粗砾岩之间,主关键层破断周期间隔距离为190 m;导水裂缝带发育高度约245 m,导通至洛河组下段砂岩裂隙潜水含水层;顶板离层突水具有动态周期性特点,当"空腔型"离层形成稳定"储水体"后,随着顶板覆岩破坏程度的增加以及主关键层的破断,稳定"储水体"被打破,沿导水裂缝带涌入矿井,造成突水事故;随顶板覆岩的周期性破断,离层突水周期性发生。     

采场覆岩中复合关键层的形成条件与判别方法

在采场覆岩运动中起主要控制作用的岩层为关键层，而有时关键层是由2层或2层以上岩层形成的复合岩层所组成，我们称其为复合关键层．本文在深入揭示复合岩层形成机理的基础上，给出了形成复合岩层的力学条件与数学表达式，进而建立了采场覆岩中复合关键层的判别方法，并编写了复合关键层的判别程序．实例分析表明，复合关键层在岩层运动中是客观存在的，比同组岩层分开后的单一岩层的控制作用的线性叠加要大得多．本项研究是岩层控制的关键层理论研究的深入和发展，将有力促进岩层控制理论和技术的发展．     

Analysis of Water Insulating Effect of Compound Water-Resisting Key Strata in Deep Mining

The problem of water preservation in mining and the prevention of water-bursts has been one of the more important issues in deep mining. Based on the concept of water-resisting key strata, the mechanics model of the key strata is established given the structural characteristics and the mechanical properties of the roof rock layers of the working face in a particular coal mine. Four other models were derived from this model by re-arranging the order of the layers in the key strata. The distribution characteristics of stress, deformation, pore pressure and the flow vector of all the models are computed using the analytical module of fluid-structure interaction in the FLAC software and the corre- sponding risks of a water-burst are analyzed. The results indicate that the water-insulating ability of the key strata is related to the arrangement of soft and hard rocks. The water-insulating ability of the compound water-resisting key strata （CWKS） with a hard-hard-soft-hard-soft compounding order is the best under the five given simulated conditions.     

岩层移动模拟研究中加载问题的探讨

基于岩层控制关键层理论,通过相似材料模拟实验及UDEC与FLAC数值模拟计算,对岩层移动模拟研究中将部分岩层省略,而代之以均布载荷作用在模型上部边界的作法所存在的问题及应遵循的原则进行了研究。结果表明,当简化为均布载荷的岩层中包含关键层时,将引起岩层载荷分布特征的改变,从而导致岩层破断距模拟结果的失真;只有主关键层上部的岩层可以简化为均布载荷,包含关键层时不能简化为均布载荷,其等值载荷与被省略岩体中关键层的位置及其破断特征有关。     

采动岩体的关键层理论研究新进展

在分析关键层理论的基本原理的基础上,详细介绍了有关键层复合效应对采场矿压与岩层移动的影响,以及综述了关键层理论在采矿压控制、岩层移动与地表沉陷控制和煤层瓦斯抽放等应用研究方面的最新进展。     

Relationship between water inrush from coal seam floors and main roof weighting

A water-resistant key strata model of a goaf floor prior to main roof weighting was developed to explore the relationship between water inrush from the floor and main roof weighting. The stress distribution,broken characteristics, and the risk area for water inrush of the water-resistant key strata were analysed using elastic thin plate theory. The formula of the maximum water pressure tolerated by the waterresistant key strata was deduced. The effects of the caved load of the goaf, the goaf size prior to main roof weighting, the advancing distance of the workface or weighting step, and the thickness of the waterresistant key strata on the breaking and instability of the water-resistant key strata were analysed.The results indicate that the water inrush from the floor can be predicted and prevented by controlling the initial or periodic weighting step with measures such as artificial forced caving, thus achieving safe mining conditions above confined aquifers. The findings provide an important theoretical basis for determining water inrush from the floor when mining above confined aquifers.     

充填开采时上覆岩层的活动规律和稳定性分析

采空区充填开采为“三下”煤炭的合理开采创造了条件，本结合现场地质条件，分析了采空区全部充填条件下，充填体压缩率对上覆岩层活动的影响规律，分析了该条件下关键层的稳定性及其对上覆岩层活动的影响，提出了保持岩层移动在合理范围的充填体允许压缩率，研究结果可为采空区充填开采的有效实施提供参考。     

F-structure model of overlying strata for dynamic disaster prevention in coal mine

The rupture and movement scope of overlying strata upon the longwall mining face increased sharply as the exploitation scale and degree growing recently, and the spatial structure formed by fractured strata became much more complex. The overlying strata above the working face and adjacent gobs would affect each other and move cooperatively because small pillar can hardly separate the connection of overlying strata between two workfaces, which leads to mining seismicity in the gob and induces rockburst disaster that named spatial structure instability rockburst in this paper. Based on the key stratum theory, the F-structure model was established to describe the overlying strata characteristic and rockburst mechanism of workface with one side of gob and the other side un-mined solid coal seam. The results show that F-structure in the gob will re-active and loss stability under the influence of neighboring mining, and fracture and shear slipping in the process of instability is the mechanism of the seismicity in the gob. The F-structure was divided into two categories that short-arm F and long-arm F structure based on the state of strata above the gob. We studied the underground pressure rules of different F-structure and instability mechanism, thus provide the guide for prevention and control of the F-structure spatial instability rockburst. The micro-seismic system is used for on-site monitoring and researching the distribution rules of seismic events, the results confirmed the existence and correct of F-spatial structure. At last specialized methods for prevention seismicity and rockburst induced by F-structure instability are proposed and applied in Huating Coal Mine.     

覆岩注浆减沉钻孔布置的试验研究

基于岩移关键层理论,通过试验与理论研究证明了采动覆岩离层主要出现在关键层下,并揭示了离层分布的动态规律．在此基础上论述了覆岩离层注浆减沉钻孔布置的原则,为注浆减沉钻孔设计提供了理论依据．     

Investigation on fracture models and ground pressure distribution of thick hard rock strata including weak interlayer

Dynamic disasters, such as rock burst due to the breaking of large area stiff roof strata, are known to occur in the hard rock strata of coal mines. In this paper, mechanical models of the fracturing processes of thick hard rock strata were established based on the thick plate theory and numerical simulations. The results demonstrated that, based on the fracture characteristics of the thick hard rock strata, four fracture models could be analyzed in detail, and the corresponding theoretical failure criteria were determined in detail. In addition, the influence of weak interlayer position on the fracture models and ground pressure of rock strata is deeply analyzed, and six numerical simulation schemes have been implemented. The results showed that the working face pressure caused by the independent movement of the lower layer is relatively low. The different fracture type of the thick hard rock strata had different demands on the working resistance of the hydraulic powered supports. The working resistance of the hydraulic powered supports required by the stratified movements was lower than that of the non-stratified movements.     

Mechanism of rock burst caused by fracture of key strata during irregular working face mining and its prevention methods

To study the occurrence mechanism of rock burst during mining the irregular working face, the study took irregular panel 7447 near fault tectonic as an engineering background. The spatial fracture characteristic of overlying strata was analyzed by Winkler elastic foundation beam theory. Furthermore, the influence law of panel width to suspended width and limit breaking span of key strata were also analyzed by thin plate theory. Through micro-seismic monitoring, theoretical analysis, numerical simulation and working resistance of support of field measurement, this study investigated the fracture characteristic of overlying strata and mechanism of rock burst in irregular working face. The results show that the fracture characteristic of overlying strata shows a spatial trapezoid structure, with the main roof being as an undersurface. The fracture form changes from vertical “O-X” type to transverse “O-X” type with the increase of trapezoidal height. From the narrow mining face to the wide mining face, the suspended width of key strata is greater than its limit breaking width, and a strong dynamic load is produced by the fracture of key strata. The numerical simulation and micro-seismic monitoring results show that the initial fracture position of key strata is close to tailgate 7447. Also there is a high static load caused by fault tectonic. The dynamic and static combined load induce rock burst. Accordingly, a cooperative control technology was proposed, which can weaken dynamic load by hard roof directional hydraulic fracture and enhance surrounding rock by supporting system.