Deformation characteristics of surrounding rock of broken and soft rock roadway

A similar material model and a numerical simulation were constructed and are described herein.The deformation and failure of surrounding rock of broken and soft roadway are studied by using these models.The deformation of the roof and floor,the relative deformation of the two sides and the deformation of the deep surrounding rock are predicted using the model.Measurements in a working mine are compared to the results of the models.The results show that the surrounding rock shows clear rheological features under high stress conditions.Deformation is unequally distributed across the whole section.The surrounding rock exhibited three deformation stages:displacement caused by stress concentration,rheological displacement after the digging effects had stabilized and displacement caused by supporting pressure of the roadway.Floor heave was serious,accounting for 65% of the total deformation of the roof and floor.Floor heave is the main reason for failure of the surrounding rock.The reasons for deformation of the surrounding rock are discussed based on the similar material and numerical simulations.

An experimental study of a yielding support for roadways constructed in deep broken soft rock under high stress

A rationally designed support for deep roadways excavated in broken soft rock under high stress was investigated. The deformation and failure characteristics and the mechanism of ''yielding support'' was studied for anchor bolts and cables. The rail roadway of the 2-501 working face in the Liyazhuang Mine of the Huozhou coal area located in Shanxi province was used for field trials. The geological conditions used there were used during the design phase. The new ''highly resistant, yielding'' support system has a core of high strength, yielding bolts and anchor cables. The field tests show that this support system adapts well to the deformation and pressure in the deep broken soft rock. The support system effectively controls damage to the roadway and ensures the long term stability of the wall rock and safe production in the coal mine. This provides a remarkable economic and social benefit and has broad prospects for fur- ther application.

Deformation mechanism of high-stress and broken-expansion surrounding rock and supporting optimization based on the gray correlation theory

Aiming at the large deformation and support problems of high-stress and broken-expansion surrounding rock, and taking 1 000 m level roadway of Mine II in Jinchuan as the research object, an investigation on the deformation and damage of roadway surrounding rock and an analysis of its mechanism were carried out. The gray correlation theory was used in support scheme optimization design. First, causes and mechanism of deformation of the 1 000 m horizontal transport channel were analyzed through field investigation, laboratory test and data processing methods. We arguued that poor engineering geological conditions and deep pressure increases were the main factors, and the deformation mechanism was mainly the ground deformation pressure. Second, the gray correlation theory was used to construct supporting optimization decision method in the deep roadway. This method more comprehensively considers various factors, including construction, costs, and supporting material functions. The combined support with pre-stressed anchor cables, shotcrete layer, bolt and metal net was put forward according to the actual roadway engineering characteristics. Finally, 4 support schemes were put forward for new roadways. The gray relational theory was applied to optimizing the supporting method, undertaking technical and economic comparison to obtain the correlation degree, and accordingly the schemes were evaluated. It was concluded as follows: the best was the flexible retaining scheme using the steel strand anchor; the second best was the one using plate anchors on the top and rigid common screw steel bolt on the two sides; the third was; the rigid common screw steel bolt in full section of roadway; and the worst is the planished steel rigid support. The optimized scheme was applied to the 1000 m level of new excavation roadway. The results show that the roadway surrounding rock can reach a stable state after 5 to 6 months monitoring, with a convergence rate less than 1 mm/d.

矿井破碎巷道围岩变形机理分析及支护技术研究

针对矿井破碎巷道在施工中易受围岩破碎、顶底板压力大等因素的影响,存在巷道围岩易变形,难支护安全生产隐患大的问题,以山西某矿10-208破碎巷道工程概况为例,结合巷道围岩变形机理,设计了具体的巷道围岩控制方案,并进行了应用测试,测试结果表明,通过给巷道进行注浆加固与采用锚杆索进行联合支护后,该巷道围岩变形得到了有效控制,该回采巷道过破碎段过程中顶底板最大累计变形量为49.5mm,巷道两帮最大累计变形量为64.6mm,取得了较好的围岩控制效果,可为类似工况下的矿井破碎巷道围岩的控制提供参考。

超前注浆加固技术在掘进工作面过破碎带中的应用

G煤矿在回采工作面5521-10回风巷掘进期间,受到褶曲、断层等地质构造及煤层赋存条件的影响,构造前后形成集中应力区,煤岩体处于松软破碎状态,原有锚网支护方式无法有效满足巷道围岩控制要求,巷道掘进期间易发生漏顶造成灾害。针对上述问题,结合掘进工作面实际情况,提出了解决思路,决定采用尤卡尼加固剂进行巷道煤岩体超前注浆加固的技术措施,并设计了相应的技术参数,注浆加固后使破碎煤岩体力学性质得到了有效改善;注浆加固技术方案实施后,选择合理的支护参数对巷道进行有效支护,并对巷道进行离层变形监测、锚杆锚索受力特征现场测试,其结果验证了该技术的合理性。

高海拔破碎围岩排水巷道锚索支护参数优化

合理的支护形式与支护参数是确保巷道围岩稳定的关键。巨龙铜矿排水巷道Ⅳ级围岩区域采用锚杆+金属网+喷浆进行联合支护效果较差。针对巨龙铜矿Ⅳ级围岩区域支护存在的问题,在现有支护基础上增加锚索和钢拱架支护,同时增加喷浆厚度。设计了不同锚索支护参数,利用有限元数值模拟软件进行了锚索支护参数优化。结果表明:巷道围岩顶板处存在明显应力集中现象。随着锚索支护参数增加,巷道顶板处最大应力值增加。随着锚索间排距增大,巷道顶板最大位移增加,锚杆间距由1.2 m增加至2.0 m,巷道顶板位移分别为4 mm、4.38 mm、4.82 mm。锚索最优支护参数为1.6 m×2.4 m。研究结果为类似巷道锚索支护参数选取提供了理论参考。

破碎顶板巷道围岩支护技术研究

山西某矿11302运输联巷受顶板岩体承载能力差、破碎等因素影响,围岩控制难度较高.结合现场条件对围岩变形控制中面临问题进行分析、提出控制策略,具体采用超前注浆方式提高顶板破碎岩体稳定性、承载能力,后通过锚网索方式控制围岩变形;对顶板注浆参数及锚杆索布置参数等进行详细设计.现场应用后,锚杆索锚固端稳定,监测锚杆、锚索锚固力分别在100 kN、150 kN以上;11302运输联巷围岩变形大问题得以较好控制,顶底板、巷帮变形量分别控制在59 mm、68 mm以内.

破碎软煤大变形回采巷道稳定性分析及支护技术研究

鸿兴煤业由于巷道煤层软弱、裂隙发育、围岩破裂变形不致密、支护参数不合理等问题,给矿井的安全开采带来了巨大的挑战。结合理论,分析了主动支护和被动支护对巷道稳定性的影响,提出了新的支护方案,并进行了现场试验。试验过程中,在29107巷道中实施了“螺栓、W钢带”+“锚索、锚索梁”+“工字钢棚”的主动式被动耦合支护方案,并对巷道两壁和顶板、底板位移收敛变形进行了实时监测,结果表明,该方案有效地控制了巷道围岩变形,保证了巷道的稳定性。

破碎顶板下回采巷道超前支护参数优化研究

为解决三交河矿10-205工作面正巷破碎顶板下超前支护区巷道变形大,劳动强度高等问题,开展了超前支护优化研究。通过现场实测和室内试验,获得煤岩力学参数,采用注浆锚索代替部分单体支柱,设计了3种排距超前支护优化方案。通过FLAC3D分析不同方案下巷道位移应力分布规律。最后在10-205正巷进行了现场试验,结果表明:注浆锚索优化方案下,超前30 m范围内单体立柱排距由0.8 m增加至1.6 m,减少16排立柱,显著减少了单体支柱数量,降低了劳动强度,增加了作业空间,为类似工况下回采巷道超前支护提供了借鉴。

近距离下煤层中空注浆锚索注浆前后周边剪应力作用机理

为解决近距离下煤层破碎巷道围岩难以控制的问题,基于理论分析和数值模拟研究中空注浆锚索注浆前后对破碎围岩的控制效果,即注浆前后中空注浆锚索与围岩的周边剪应力作用机理。结果表明:注浆前锚固段符合粘弹性本构模型,剪应力曲线呈现线性增加到非线性下降再到稳定的单峰值,注浆后巷道周围预应力场沿锚索形成一个渐变式的整体,使巷道围岩应力场重新分布,剪应力强度随之降低,应力曲线转变二次线性快速增加到非线性快速下降再到稳定的双峰值曲线,有效提高破碎围岩和软岩巷道的抗剪强度。

掘进工作面过顶板破碎区支护分析

在煤矿巷道掘进过程中,一些地质构造区域的顶板比较破碎,对掘进安全性产生了巨大的影响。结合A矿405工作面实际地质情况,探讨了其巷道掘进过顶板破碎区采取的支护方案。首先,针对顶板破碎区,制定了详细的岩性探测方案;然后,根据实际情况,进行了永久支护和临时支护设计;最后,分析了顶板破碎区支护的施工管理。可以为特殊地质条件下的巷道支护提供一定的技术参考。

近距离煤层采空区下巷道支护技术研究

3号煤层32501综采工作面位于2号煤层采空区下方4.3~7.9 m位置,采面回采巷道受上覆采空区影响,导致围岩变形控制难度较大.采用理论方法计算2号煤层回采后底板最大破坏深度,分析2号煤层回采会破碎3号煤层顶板完整性,导致顶板破碎,给采面回采巷道围岩控制带来制约.结合3号煤层埋深较浅、地应力显现不明显且回采区地质构造简单特点,提出采用锚网索方式支护围岩,顶板通过高强锚杆+短锚索支护,巷帮帮肩采用高强长锚杆补强、避免巷帮片帮,辅助采用金属网、W钢带提高护表强度.现场应用后,32501综采工作面围岩变形量在较小范围内,实现了近距离煤层采空区下破碎顶板回采巷道围岩变形有效控制.

综掘煤巷过断层支护分析

针对2315辅助进风巷掘进期间揭露断层问题,为确保巷道安全高效掘进并实现断层影响区围岩变形有效控制,结合现场条件提出顶板采用全锚索支护、巷帮采用全长自巩固锚杆支护、在断层破碎带采用注浆锚索补强;考虑2315辅助进风巷后期切顶留巷需要,针对性对顶锚索及巷帮锚杆布置方案进行设计.现场应用后,2315辅助进风巷在断层影响范围内围岩始终保持稳定,围岩变形量在允许范围内,现场采用的支护措施可满足巷道快速掘进以及破碎围岩变形有效控制需要.

沿空留巷复用巷道快速修复技术研究

煤矿开采中,沿空留巷经历采动,容易遭到变形破坏。本文以友众煤矿30106进风巷为研究对象,通过采用面内小煤柱沿空留巷工艺,30106进风巷留巷后作为30108运输巷使用的复用加固。通过30106进风巷的工业性试验,成功在巷道复用前加固1 800 m,并实现了30108工作面回采前作为30108运输巷的正常使用,从而保持巷道围岩的稳定,完成巷道复用的加固设计。此次工程实现沿空留巷的修复和加固,为相似条件工作面巷道维护提供一定的参考。

浅埋厚煤层软岩巷道支护参数设计及应用

目前煤矿常采用锚杆(索)对巷道两帮及顶板进行主动支护,但受巷道所处力学环境、地质条件等多种因素影响,针对软岩巷道锚杆支护参数设计及理论选择较为困难,使巷道支护环境较差。本文结合理论与现场工程地质条件,针对五举煤矿13207工作面软岩巷道中存在的顶板破碎严重问题,对两巷道支护参数进行设计及应用。参数选择为顶板及帮部均采用左旋无纵筋螺纹钢锚杆,规格分别为φ22 mm×2 800 mm、φ22 mm×2 400 mm,顶板及帮部分别采用φ21.8 mm×7 300 mm的1×19股高强度锚索与φ21.6 mm×5 300 mm的1×7股高强度锚索,锚杆预紧扭矩不小于300 N·m,锚索张拉力不小于200 k N。现场应用结果表明,巷道围岩变形得到有效控制,整体支护效果良好,为附近相似条件矿井提供借鉴。

北辛窑矿南翼回风大巷过断层支护技术分析

北辛窑矿南翼回风大巷通过断层破碎带时,因围岩裂隙较发育、夹带部分裂隙水,造成巷道稳定性差,岩巷若采用“锚网索喷”支护,不足以保证岩巷围岩稳定及其安全使用;决定采用“锚网索+U型棚+注浆+喷浆”联合支护技术方案,并通过实时矿压监测巷道围岩变形;实践表明,联合支护技术方案应用后巷道顶板未出现明显变形,巷道支护质量逐步趋于稳定,能满足巷道的正常施工和安全使用。

破碎软岩巷道支护的模拟分析与现场应用

针对破碎软岩巷道断面收缩快、频繁返修且随着返修频次增加巷道支护难度逐渐增大的问题,运用数值模拟软件FLAC对“帮顶锚杆支护、帮顶锚杆加全断面注浆支护以及全断面锚杆支护加注浆”三种不同的巷道修复方案进行模拟分析,并通过现场矿压监测巷道的变形量;注浆使破裂岩体固结后强度增强、抗变形性能明显提高,增强了巷道的稳定性;底板锚杆可使底板围岩形成良好的结构体,从而提高围岩强度、有效控制巷道底鼓的发生。

Study on Repairing Permanent Transportation Roadway in Deep Mining by Bolt-Shotcrete and Mesh Supporting

The roadway support in many places of Jiulongkou Colliery, Fengfeng Mining Bureau, such as in the Permanent transportation roadway, was failed or locally caved, which seriously affected the colliery’s coal production performance and safety. Based on analysis of supporting objects for roadway repairing, this paper proposes the supporting parameters and condruction technics. The industrial ted of 70m long roadway repairing shows that the proposed parameters and technics of bolt shotcrete and mesh support for roadway repairing are reasouable, bring good technical and economic results for the colliery, and the repairing is successful.

THE THEORY OF SUPPORTING BROKEN ZONE IN SURROUNDING ROCK

The first topic discussed in this paper is to evaluate the present supporting theories,among which the typical two are collapse arch and elasto-plastic theories. The former is rather limited in practical application,and the latter is built up on some assumptions which is inconsis-tent with the reality,for it is of no need to support a roadway of which the surrounding rock is in elasto-plastic state. The second topic is to prove the objective existence of the broken zone in surrounding rock(BZSR) by a series of laboratory experiments and field measurements. The paper indicates that the object to be supported mainly is the bulking or expanding force resulted from the development of BZSR. This is remarkably different from the existing points of view which have been generally recognized nowadays. So far ,this theory has been tested in supporting more than ten thousand meters roadways located in various strata and has proved itself to have a great technoeconomical benefit.

Convergent mechanism of roadway driven along with strong roof of special thick stratum and its controlled measures

The trapezoidal cross-section roadway, driven along with its medium and fine grain sandstone roof in special thick stratum, was situated in shale strata. Rock-lining wall was employed in roadway, which its roof is in the free situation. Under the action of virgin stress, the surrounding rock of roadway was in stability. While under the action of fixed abutment pressure arisen from protection pillar of roadway, which its two sides?seams were extracted, free strong roof of roadway was in the stability. But its two sides?rock-lining walls was fractured, partially broken into pieces, and its floor heave was ob-vious. The velocity of floor heave is 0.4～0.8 mm/d. The size of broken zone of sur-rounding rock of roadway increases doubly. An effective load coefficient of surrounding rock to was quoted illustrate these phenomena. The main reasons of roadway conver-gence are that, rock property of surrounding rock is inferior, protection pillar affects its stability, and supporting pattern employed is improper. At last, effective measures to control roadway convergence should be bolting and grouting lining, which mainly con-solidates surrounding rock of roadway.