锚杆支护条件下围岩应力及变形特点分析

本文采用数值模拟方法比较分析了有无锚杆作用下深部开采圆形和矩形巷道围岩应力、应变及变形随距巷道表面距离变化的不同特点。结果表明:锚杆随距巷道表面一定范围围岩应力、应变及变形减小,围岩应力、应变及变形随距巷道表面距离增加而衰减速度变缓;距巷道表面较远处围岩应力反而增加。锚杆作用下围岩整体移动趋势增加并将近处围岩较大应力传递到远处。     

深部高应力回采巷道支护技术研究

针对深部开采巷道围岩变形快、变形量大的重大难题,根据兴东矿2121工作面回采过程中巷道围岩的变形特征,通过普氏理论计算出锚杆(索)支护参数,提出了5种不同支护方案,利用FLAC3D数值模拟软件,依次计算出各种方案的顶板下沉量和两帮移近量。结果表明:(1)深部巷道在高应力作用下,巷道围岩变形总量较大,特别是在巷道变形初期,巷道围岩变形速率大,在此条件下采用锚杆索联合支护,可以有效控制围岩的变形和破坏;(2)通过加强两帮的支护,可提高深部巷道围岩整体的承载能力,减少顶板下沉,促进顶板形成稳定结构;(3)增加锚索的预紧力,使锚杆与锚索同步承载,可大大增加支护结构的稳定性,有效控制围岩变形。现场试验表明,锚杆索联合支护可有效提高巷道围岩的承载能力,减少围岩移动和变形,具有良好的支护效果。     

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.     

一种协调控制巷道围岩变形的新型支架

针对现有支护方式不能有效控制部分软岩巷道围岩变形的状况,提出一种协调控制围岩变形支架来提高巷道围岩支护力,进而减少巷道整体变形量.介绍了该新型支架的结构组成及工作原理,并进行了力学分析.该支架结构简单、操作方便、无材料消耗、可重复使用,可用于协调控制回采巷道、软岩巷道等大变形巷道的变形.随着深部矿井开采力度的加大,协调控制深部巷道围岩的新型支架将具有较好的推广应用价值.     

深部巷道围岩控制的有效途径

针对煤炭开采逐渐由浅部转向深部,提出在深部复杂的力学环境下,岩体力学行为和工程响应条件下深部巷道围岩控制的有效方法.文中确定了影响巷道围岩稳定性的因素,分析了各影响因素对巷道围岩稳定性的影响规律,认为改善巷道围岩应力状态及围岩力学性能、合理选择巷道支护形式和提高其支护阻力以及优化巷道断面等为深部巷道围岩控制的有效途径.现场应用结果表明:巷道首选在时空上避开高应力作用,底板掘卸压巷可使巷道变形量控制在20mm以内,上行开采改善了深部巷道应力环境,工作面推进速度由48 m/月提高到90m/月左右,巷道迎头超前钻孔卸压后巷道顶底板移近量减小了900mm;采用高强、高预紧力、高延伸率锚杆(索)支护系统配合合理的注浆加固参数,有效提高巷道围岩强度,巷道围岩变形量降低40%以上.另外,尽量选择弧形断面,壁后充填等措施,实现支护体均匀承载,提高支护阻力.     

深部巷道组合钢架合理支护间距数值模拟研究

为确定深部巷道组合钢架合理支护间距,有效控制深部巷道围岩变形,提高巷道施工机械化水平,以焦作煤业集团赵固(新乡)能源有限责任公司赵固二矿11071工作面回风巷为研究背景,采用三维有限差分软件对深部巷道6种支护方案的围岩变形、应力和塑性区分布进行对比分析.结果表明:深部巷道围岩变形和塑性区分布受围岩局部让压效应影响显著;在巷道拱顶、拱底以及两帮与底板交接部位均易出现应力集中现象;巷道开挖引起的岩体破坏以剪切破坏为主.根据数值模拟试验得出了深部巷道组合钢架合理支护间距,优选出的最佳支护方案可以减缓围岩变形,改善围岩应力状态,减少围岩塑性破坏范围,从而提高深部巷道围岩的稳定性.     

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.     

三软综放沿空锚网索支护巷道回采期间围岩变形特征

针对三软综放沿空巷道围岩大变形、难支护的特点,提出采用锚网索支护新技术,通过对试验巷道数值模拟以及表面位移、围岩深部位移和围岩应力的现场监测,分析了试验巷道矿压显现活动规律,掌握了试验巷道在锚网索支护下的围岩变形规律,这为锚网索支护在三软煤层巷道的推广应用和支护参数设计提供了科学依据.     

不同断面形式深埋巷道围岩破坏数值模拟分析

以Ⅲ级围岩为例,利用有限差分软件FLAC对不同埋深情况下不同断面形式的巷道进行数值模拟,分析矩形、直墙拱形和圆形断面巷道围岩应力应变、围岩塑性区随埋深的变化规律及特点。结果表明：拱形断面巷道的围岩变形、围岩塑性区最小,尤其是顶板下沉量较矩形和圆形断面巷道的要小得多;圆形断面巷道围岩水平向位移最小;矩形断面巷道围岩应力及变形随埋深增加幅度都要大于拱形和圆形断面巷道。     

深部巷道围岩控制的关键技术研究

针对深部煤炭赋存条件复杂、巷道矿压显现日趋激烈,相当一部分巷道布置在岩石松软、变形剧烈的岩体、煤体或半煤岩体中,深部巷道"失稳"普遍存在的突出难点进行研究.文中阐述了深部巷道围岩控制的两个突出难点:底鼓和蠕变,针对性地提出了相应的控制技术——通过加固底板和巷道帮角控制底鼓,采用合理的一次支护和二次支护来实现巷道的长期稳定.研究结果表明:依据深部巷道底鼓的"两点三区"变形特征,底板锚杆、注浆孔深度应深入底板岩层"零位移点"以下,配合帮角加固有效控制深部巷道底鼓;采用合理的一次支护和二次支护保证锚固端提供的径向应力大于巷道蠕变所需的径向应力,使巷道变形速度维持在0.02mm/d左右,保持了巷道围岩的长期稳定并取得良好的效果,对保证深部煤炭资源安全开采具有重大意义.     

深部巷道围岩变形试验与数值模拟研究

为了研究深部软岩巷道的变形破坏特性,以淮南矿区某煤矿13-1煤回采巷道为例,在现场调查回采巷道工程概况的基础上,开展了室内深部回采巷道围岩变形特性相似模拟试验,并基于块体离散元法,建立了深部回采巷道围岩的数值模型,模拟了开挖过程中围岩的变形特性。相似模拟试验和数值模拟试验结果表明,深部巷道围岩的典型特征为:巷道底臌量两帮移近量顶板下沉量,巷道不同围岩受开挖扰动的位移影响范围不同,底板为3.5 m,顶板为2.45 m,两帮为5.5 m。     

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.     

Influence of dynamic pressure on deep underground soft rock roadway support and its application

Due to high ground stress and mining disturbance, the deformation and failure of deep soft rock roadway is serious, and invalidation of the anchor net-anchor cable supporting structure occurs. The failure characteristics of roadways revealed with the help of the ground pressure monitoring. Theoretical analysis was adopted to analyze the influence of mining disturbance on stress distribution in surrounding rock,and the change of stress was also calculated. Considering the change of stress in surrounding rock of bottom extraction roadway, the displacement, plastic zone and distribution law of principal stress difference under different support schemes were studied by means of FLAC3D. The supporting scheme of U-shaped steel was proposed for bottom extraction roadway that underwent mining disturbance. We carried out a similarity model test to verify the effect of support in dynamic pressure. Monitoring results demonstrated the change rules of deformation and stress of surrounding rock in different supporting schemes. The supporting scheme of U-shaped steel had an effective control on deformation of surrounding rock. The scheme was successfully applied in underground engineering practice, and achieved good technical and economic benefits.     

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.     

Roadway deformation during riding mining in soft rock

“Riding mining” is a form of mining where the working face is located above the roadway and advances parallel to it. Riding mining in deep soft rock creates a particular set of problems in the roadway that include high stresses, large deformations, and support difficulties. Herein we describe a study of the rock deformation mechanism of a roadway as observed during riding mining in deep soft rock. Theoretical analysis, numerical simulations, and on site monitoring were used to examine this problem. The stress in the rock and the visco-elastic behavior of the rock are considered. Real time data, recorded over a period of 240 days, were taken from a 750 transportation roadway. Stress distributions in the rock surrounding the roadway were studied by comparing simulations to observations from the mine. The rock stress shows dynamic behavior as the working face advances. The pressure increases and then drops after peaking as the face advances. Both elastic and plastic deformation of the surrounding rock occurs. Plastic deformation provides a mechanism by which stress in the rock relaxes due to material flow. A way to rehabilitate the roadway is suggested that will help ensure mine safety.     

综放回采巷道围岩力学特征实测研究

通过对综放面回采巷道围岩的深部位移、表面位移、应力分布以及支架荷载的实测分析，得出综放面回采巷道围岩力学特征分布规律．研究表明，临近工作面巷道围岩处于支承压力降低区，支架荷载下降，但支架和围岩变形最剧烈，表明巷道围岩处于岩石峰后的力学状态．围岩变形主要发生支承压力影响区，合理的巷道支护应能控制采动影响剧烈阶段的围岩变形，顺槽支护设计理念应从载荷控制向变形控制转变．     

深井巷道围岩应力及变形规律的数值分析

采用非线性有限元法，对深井巷道围岩应力及变形状态进行了数值计算．分析了巷道埋深、围岩性质和断面形状对围岩变形的影响．结果表明：当巷道埋探小于某一临界深度时，巷道周边围岩移近量随巷道埋深增加呈线性增加；当超过临界深度时，巷道围岩移近量呈现指数规律增加趋势．围岩变形破坏的临界深度取决于围岩的力学性质及巷道断面形状等因素．     

Deformation control of asymmetric floor heave in a deep rock roadway: A case study

In order to control asymmetric floor heave in deep rock roadways and deformation around the surrounding rock mass after excavation, in this paper we discuss the failure mechanism and coupling control countermeasures using the finite difference method (FLAC^3D) combined with comparative analysis and typical engineering application at Xingcun coal mine. It is indicated by the analysis that the simple symmetric support systems used in the past led to destruction of the deep rock roadway from the key zone and resulted in the deformation of asymmetric floor heave in the roadway. Suitable reinforced support countermeasures are proposed to reduce the deformation of the floor heave and the potential risk during mining. The application shows that the present support technology can be used to better environmental conditions. The countermeasures of asymmetric coupling support can not only effectively reduce the discrepancy deformation at the key area of the surrounding rock mass, but also effectively control floor heave, which helps realize the integration of support and maintain the stability of the deep rock roadways at Xingcun coal mine.     

移动压力支承作用下底板巷道围岩变形与采深的关系

本文阐明了移动支承压力影响区与采深的关系，提出了用有效载荷系数来反映动压作用下底板巷道围岩变形量的大小，结合孙村煤矿实测资料，总结出在跨采期间，底板巷道围岩变形量与有效载荷系数之间的定量关系，为深井开采移动支承压力作用下，底板巷道围岩变形量预测预报提供了一种方法。     

护巷煤柱宽度与巷道围岩变形的关系

本文在分析研究大量受采动影响巷道的矿压显现规律和围岩变形的基础上,提出了巷道在采动期间的围岩变形量,以及采动稳定期间的围岩变形速度同护巷煤柱宽度之间的关系,并得出巷道服务期间的围岩变形总量与护巷煤柱宽度之间的关系式,为选择护巷煤柱宽度提供主要依据。