深部软岩巷道围岩变形分析与控制

针对某深部软岩巷道支护困难问题,首先对围岩进行力学性能试验,然后利用有限元分析方法,在基于不同埋深软岩巷道围岩变形特征研究的基础上,从巷道开挖和围岩支护两方面对深部高地应力软岩巷道围岩变形与控制进行深入研究.结果表明:随软岩巷道埋深增大,巷道围岩变形呈线性增大趋势;在深部高地应力下掘进巷道时,全断面开挖法围岩变形最大,台阶法次之,CD法最小;支护时采用柔性与刚性联合支护,围岩变形最小.联合支护技术能充分释放软岩巷道围岩变形能,发挥围岩自承能力并与支护体系共同作用,可以有效控制深部软岩巷道围岩变形,从而保证深部软岩巷道围岩的稳定性.     

千米深井软岩巷道破坏机理及支护技术研究

基于矿井开采逐渐向深部发展,巷道围岩呈现高地压、大变形、难支护的特点,常规锚网支护已难以控制巷道围岩变形的情况.通过对华丰煤矿-1?100水平巷道破坏机理的研究,提出了采用马蹄形巷道支护断面和全封闭支护的理念,加强底板承载能力和巷道抗蠕变能力;根据千米深井巷道围岩流变特性,研究得出了围岩地压得到合理释放趋于稳定时进行永久支护的时机和距离,并在永久支护中实施锚注加固,使松散破碎岩块胶结成整体提高了围岩的内聚力和内摩擦角,使围岩由“软”变“硬”,使无支护作用的围岩体变为支护结构,同时锚注锚杆成为全长锚固锚杆,加强了围岩的加固效果,达到安全永久支护巷道的目的.     

软岩巷道锚喷支护破坏分析与对策

软岩巷道锚喷支护破坏原因主要有巷道底板无支护或支护的强度不够,底板流变极易发展,形成了围岩体的流变通道;大部分锚杆支护为低工作阻力值,支护作用没有得到有效发挥;混凝土喷层和围岩体变形不匹配,导致喷层体离层、剪切破坏;钢笆网抵抗破坏和变形的能力弱,降低了网喷层的强度和抗变形能力.采取的支护对策有底板反拱加强支护,避免局部围岩体的整体移动,实现巷道周边岩体的均匀收敛变形;选用长锚杆,更好地控制巷道围岩的变形;初喷混凝土为厚度20mm薄喷层,实现初喷层与巷道围岩体的同步变形;用直径4mm冷拔钢丝编织金属网替代钢笆网,提高网喷层支护体的强度与抗变形能力;二次锚杆支护在复喷混凝土后进行,防止网喷层与围岩体离层现象的发生.     

软岩巷道锚喷支护破坏分析与对策

软岩巷道锚喷支护破坏原因主要有:巷道底板无支护或支护的强度不够,底板流变极易发展,形成了围岩体的流变通道;大部分锚杆支护为低工作阻力值,支护作用没有得到有效发挥;混凝土喷层和围岩体变形不匹配,导致喷层体离层、剪切破坏;钢笆网抵抗破坏和变形的能力弱,降低了网喷层的强度和抗变形能力.采取的支护对策有:底板反拱加强支护,避免局部围岩体的整体移动,实现巷道周边岩体的均匀收敛变形;选用长锚杆,更好地控制巷道围岩的变形;初喷混凝土为厚度20 mm薄喷层,实现初喷层与巷道围岩体的同步变形;用直径4 mm冷拔钢丝编织金属网替代钢笆网,提高网喷层支护体的强度与抗变形能力;二次锚杆支护在复喷混凝土后进行,防止网喷层与围岩体离层现象的发生.     

数值模拟软岩巷道支护技术研究

软岩巷道多具有高应力、变形大、难支护等工程特征,单一支护方式难以控制围岩变形.通过对围岩变形机理、破坏过程分析研究,利用模拟围岩变形破坏的RFPA计算软件,建立了数值计算力学模型.对软岩巷道围岩变形破坏、应力转移过程进行模拟分析,为软岩巷道支护方案设计提供了依据.     

数值模拟软岩巷道支护技术研究

软岩巷道多具有高应力、变形大、难支护等工程特征,单一支护方式难以控制围岩变形.通过对围岩变形机理、破坏过程分析研究,利用模拟围岩变形破坏的RFPA计算软件,建立了数值计算力学模型.对软岩巷道围岩变形破坏、应力转移过程进行模拟分析,为软岩巷道支护方案设计提供了依据.     

软岩隧道(巷道)实用控制技术研究

软岩、极软岩巷道具有高地压、难支护和持续变形破坏工程特征，实践表明，现有支护难以耦合控制．文章通过对软岩工程特征、变形破坏机理分析研究，提出了软岩控制和复合型软岩向单一型转化控制的技术方法和实用支护对策．经工业性试验、应力监测表明，控制了围岩的强烈变形、保证了巷道的稳定，具有显著的技术经济效益．     

软岩巷道交叉点锚杆支护数值模拟分析

以云南恩洪煤矿软岩巷道为背景,应用数值模拟对软岩巷道交叉点3种支护方案进行分析研究.结果表明,全断面预应力锚杆支护改善了交叉点的应力集中程度,起到一定卸压作用,并控制了围岩的变形量,保证了软岩巷道交叉点的稳定.     

软岩巷道支护荷载的确定方法

通过分析巷道围岩与支护的相互作用原理 ,得出了软岩巷道失稳的原因是由于围岩自承力与支护力不足的结果 .认为一个优化的软岩巷道支护设计应在确保支护稳定的前提下 ,最大限度地释放围岩的能量 ,使以变形形式转化的工程力达到最大 ,同时最大限度地发挥围岩的自承能力 ,使工程支护力达到最小 ,而其关键是确定变形能释放时间和最佳支护时间 .软岩巷道开挖后 ,通常在巷道周围形成塑性软化区和塑性流动区 ,实施支护力就是要控制塑性流动区的范围与发展 ,达到最佳支护时间时的支护荷载为最小支护荷载 ,可以通过塑性软化区和塑性流动区内岩石的重力求得     

高应力区域煤层巷道耦合支护数值模拟试验研究

为了研究耦合支护控制巷道变形的效果,根据耦合支护原理,使用FLAC3D有限差分数值模拟软件对某矿11010工作面回风巷在不同支护参数下巷道的顶板、底板、左帮和右帮深部基点位移与围岩最大位移进行了研究.结果表明,当支护体与围岩以及支护体之间在强度、刚度、结构满足耦合支护时,巷道深部基点位移与围岩最大位移均较小,且巷道处于稳定状态所需时间较短.通过工程实例进一步说明了耦合支护能有效地控制巷道围岩变形,维护巷道稳定.     

Bolt-grouting combined support technology in deep soft rock roadway

Analyzing the mineral composition, mechanical properties and ground stress testing in surrounding rock,the study investigated the failure mechanism of deep soft rock roadway with high stress. The boltgrouting combined support system was proposed to prevent such failures. By means of FLAC3D numerical simulation and similar material simulation, the feasibility of the support design and the effectiveness of support parameters were discussed. According to the monitoring the surface and deep displacement in surrounding rock as well as bolt axial load, this paper analyzed the deformation of surrounding rock and the stress condition of the support structure. The monitor results were used to optimize the proposed support scheme. The results of field monitors demonstrate that the bolt-grouting combined support technology could improve the surround rock strength and bearing capacity of support structure, which controlled the great deformation failure and rheological property effectively in deep soft rock roadway with high stress. As a result, the long term stability and safety are guaranteed.     

Numerical simulation of the effect of coupling support of bolt-mesh-anchor in deep tunnel

The mechanical effects of bolt-mesh-anchor coupling support in deep tunnels were studied by using a numerical method, based on deep tunnel coupling supporting techniques and non-linear deformation mechanical theory of rock mass at great depths. It is shown that the potential of a rigid bolt support can be efficiently activated through the coupling effect between a bolt-net support and the surrounding rock. It is found that the accumulated plastic energy in the surrounding rock can be sufficiently transformed by the coupling effect of a bolt-mesh-tray support. The strength of the surrounding rock mass can be mobilized to control the deformation of the surrounding rock by a pre-stress and time-space effect of the anchor support. The high stress transformation effect can be realized by the mechanical coupling effect of the bolt-mesh-anchor support, whereby the force of the support and deformation of the surrounding rock tends to become uniform, leading to a sustained stability of the tunnel.     

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.     

Cable-truss supporting system for gob-side entry driving in deep mine and its application

In order to solve the large deformation controlling problem for surrounding rock of gob-side entry driving under common cable anchor support in deep mine, site survey, physical modeling experiment, numerical simulation and field measurement were synthetically used to analyze the deformation and failure characteristics of surrounding rock. Besides, applicability analysis, prestress field distribution characteristics of surrounding rock and the control effect on large deformation of surrounding rock were also further studied for the gob-side entry driving in deep mine using the cable-truss supporting system. The results show that, first, compared with no support and traditional bolt anchor support, roof cable-truss system can effectively restrain the initiation and propagation of tensile cracks in the roof surrounding rock and arc shear cracks in the two sides, moreover, the broken development of surrounding rock, roof separation and extrusion deformation between the two sides of the roadway are all controlled; second, a prestressed belt of trapezoidal shape is generated in the surrounding rock by the cable-truss supporting system, and the prestress field range is wide. Especially, the prestress concentration belt in the shallow surrounding rock can greatly improve the anchoring strength and deformation resisting capability of the rock stratum;third, an optimized support system of ‘‘roof and side anchor net beam, roof cable-truss supporting system and anchor cable of the narrow coal pillar" was put forward, and the support optimization design and field industrial test were conducted for the gob-side entry driving of the working face 5302 in Tangkou Mine, from which a good supporting effect was obtained.     

Non-destructive testing and pre-warning analysis on the quality of bolt support in deep roadways of mining districts

The bolt support quality of coal roadways is one of the important factors for the efficiency and security of coal production. By means of a self-developed technique and equipment of random non-destructive testing, non-destructive detection and pre-warning analysis on the quality of bolt support in deep roadways of mining districts were performed in a number of mining areas. The measured data were obtained in the detection instances of abnormal in-situ stress and support invalidation etc. The corresponding relation between axial bolt load variation and roadway surrounding rock deformation and stability was summarized in different mining service stages. Pre-warning technology of roadway surrounding rock stability is proposed based on the detection of axial bolt load. Meanwhile, pre-warning indicators of axial bolt load in different mining service stages are offered and some successful pre-warning cases are also illustrated.The research results show that the change rules of axial bolt load in different mining service stages are quite similar in different mining areas. The change of axial bolt load is in accord with the adjustment of surrounding rock stress, which can consequently reflect the deformation and stability state of roadway surrounding rock. Through the detection of axial bolt load in different sections of roadways, the status of real-time bolt support quality can be reflected; meanwhile, the rationality of bolt support design can be evaluated which provides reference for bolting parameters optimization.     

回采巷道锚杆支护两帮稳定性分析

根据巷道围岩应力变化特点结合锚固体变形破坏的相似材料模拟试验, 分析了巷道两帮锚固体的变形破坏特征, 指出锚杆支护巷道两帮表面主要发生张性破坏, 锚固体内部发生剪切破坏, 据此建立起回采巷道锚杆支护两帮稳定的分析模型, 提出了两帮稳定的判别准则, 即锚固体中锚杆的拉应变必须小于锚杆的允许拉应变, 在巷道两帮围岩较松软时, 还必须满足巷道周边位移值的要求     

Principle and practice of coupling support of double yielding shell of soft rock roadway under high stress

In order to ensure the safety and stability of the soft rock roadway under high stress, based on the characteristics of the surrounding rock deformation and failure, this paper presented the support technology “coupling support of double yielding shell”, then gave the design method of inner and outer shells and analyzed the principle and requirements of the support technology by taking the −850 m east belt roadway of Qujiang coal mine as the background. The field application results show that the support technology can control the soft rock roadway deformation better under high stress. The displacement between roadway sides was 851 mm, the displacement of the roof was 430 mm, and the displacement of the floor was 510 mm.     

深部沿空切顶成巷围岩稳定性控制对策

基于沿空切顶成巷技术原理,以城郊煤矿深部工作面无煤柱开采为背景,综合运用力学分析﹑模拟计算和现场试验等方法,对深部切顶成巷围岩控制关键对策进行深入研究。结果显示：切顶留巷顶板在侧向形成短臂梁结构,降低了巷旁支护体所受压力,切缝范围内岩层垮落后碎胀充填采空区,使留巷顶板下沉量降低了约50%。采空区侧顶板为切顶巷道围岩变形的关键部位,需进行加强支护;深部切顶巷道实体煤帮塑性区范围大,通过煤帮锚索支护技术可将浅部锚杆承载层锚固在弹性区稳定煤体中;深部切顶成巷来压速度快、强度大,巷内单体支柱易造成冲击破断,采用高阻力液压支架巷内临时支护时可较好地抵抗深部强动压;巷旁刚性挡矸装置因无法适应深部围岩大变形而受压弯曲破坏,深部切顶巷道巷旁挡矸结构需实现一定的竖向让位卸压方可与顶底板协调变形。在研究的基础上提出恒阻锚索关键部位支护+可缩性U型钢柔性让位挡矸+巷内液压支架临时支护+实体煤帮锚索补强的深部切顶成巷联合支护技术,并进行现场工业性试验。现场监测结果表明：留巷围岩在滞后工作面约290 m时基本稳定,且稳定后各项指标满足下一工作面使用要求。