Surrounding rock control of gob-side entry driving with narrow coal pillar and roadway side sealing technology in Yangliu Coal Mine

Gob-side entry driving can increase coal recovery ratio, and it is implied in many coal mines. Based on geological condition of 10416 working face tailentry in Yangliu Coal Mine, the surrounding rock deformation characteristics of gob-side entry driving with narrow coal pillar is analysed, reasonable size of coal pillar and reasonable roadway excavation time after mining are achieved. Surrounding rock control technology and effective roadway side sealing technology are proposed and are taken into field practice. The results showed that a safer and more efficient mining of working face can be achieved. In addition, results of this paper also have important theoretical significance and valuable reference for surrounding rock control technology of gob-side entry driving with narrow coal pillar under special geological condition.

Stability analysis and control technology of gob‑side entry retaining with double roadways by flling with high‑water material in gently inclined coal seam

To ameliorate the defects of insufcient support resistance of traditional roadside flling bodies for gob-side entry retaining(GER),overcome the inability to adapt to the deformation of surrounding rock,and isolate the goaf efectively,a new type of high-water material as a roadside flling body for GER technology with double roadways was proposed.The instability analysis and control technology of GER with double roadways by flling high-water material into a gently inclined coal seam were studied.The basic mechanical properties of the new high-water material were investigated through laboratory experiments,and their main advantages were identifed.The reasonable width of the roadside flling wall of a high-water material was obtained by combining ground pressure observation and theoretical calculations.The distribution characteristics of the stress and plastic zone of surrounding rock of GER after being stabilized by the disturbance of the working face were studied using numerical simulations,and the failure range of GER by flling with high-water material was revealed.Based on this,a coupling control technology of anchor cables and bolts+single props+metal mesh+anchor bolts is proposed.Through the coupling methods of arranging borehole peeping and observing the convergences of surrounding rock,the results demonstrate that GER with double roadways by flling with a 1.8-m-wide high-water material has a good control efect.The above research will play an active role in promoting the application of high-water materials in GER roadside flling.

Research on the width of filling body in gob-side entry retaining with high-water materials

To determine the filling body's width along the gob-side remained roadway which is underneath the gob,the authors analyzed the interaction mechanism between the roof and the supporting body along the remained roadway, based on the elastic thin plate theory of the stope roof. The stress state and mechanical response of the filling body along the remained roadway were studied. Specifically, firstly, the supporting pressure of the coal pillar which is on one side of the gob-side remained roadway was deduced.Also, an equation that is used to calculate the width of the balance area in the stress limit state was acquired. Then, an equation that is used to calculate the roof cutting force on one side of the supporting body was obtained. By using FLAC3D, the authors investigated the displacement field and stress field response laws of rock masses around the roadway with different filling body's widths. The results show that with the filling body's width increasing, the supporting ability of the filling body increases.Meanwhile, the rock mass displacement around the roadway and the filling body deformation decrease.The better the filling body's supporting effect is, the higher the roof cutting force will be. When the filling body's width is larger than 3.0 m, its internal bearing ability becomes stable and the filling body's deformation became non-apparent. Finally, analysis shows that the filling body's width should be 2.5 m.Furthermore, the authors conducted field tests in the supply roadway 1204, using high-water materials and acquired expected outcomes.

Analysis on distribution law of the abutment pressure of the integrated coal beside the road-in packing for gob-side entry retaining in fully-mechanized caving face

The three-dimensional damage constitutive relationship of coal is established and distribution law of the abutment pressure of the integrated coal beside the road-in packing for gob-side entry retaining in fully-mechanized caving face under the effect of given deformation of the main roof is analyzed by the damage mechanics theory. And the relationship between distribution of the abutment pressure and thickness of coal seam is explored. The presented result is of great theoretical significance and practical value to the study on stability control of the surrounding rock of road-in packing for gob-side entry retaining in fully-mechanized caving face.

沿空留巷技术在某矿中的应用

沿空留巷技术的应用,能够有效回收资源,防范煤体的损失,具有推广应用的价值。现针对煤矿中沿空留巷技术的应用,展开具体的论述,总结沿空留巷技术应用效果,以期为相关人员提供参考借鉴。

综采工作面上平巷沿空留巷巷帮充填技术

为减少综采工作面掘进准备巷道,提高回煤储量,实现2个临近综采工作面共用1条准备巷道,可对先采工作面上平巷沿空留巷巷帮进行充填,实现后采工作面继续应用此巷道。

长平矿大断面巷道耦合让均压支护技术研究

为了解决长平矿大采高工作面沿空留设巷道,在上一个工作面回采后变形严重,在下一个工作面回采前需要进行大规模巷修的问题,采用耦合让均压支护技术,通过理论分析、工程类比等研究手段,确定了长平矿大断面巷道沿空留巷支护方案,并进行了工业性试验。结果表明,选定的支护方案能够满足大断面巷道支护及留巷二次使用的目的,且能够保证巷道掘进速度,对相似条件下的巷道支护具有一定的指导意义。

带—网—栓式矸石袋巷旁充填支护体力学性能研究

针对沿空留巷中矸石充填体的大流变性和低支护强度等问题,提出带—网—栓式矸石袋巷旁支护技术方案。该技术选取钢带、锚网、锚栓等作为矸石袋的侧向支护材料,以此约束矸石袋的横向变形、增加矸石袋的围压,最终提升矸石充填体的支护性能。通过对矸石充填体的侧向分别添加钢带、锚网、锚栓进行承压力学试验后,矸石袋的最大承载能力提高了2～5倍。同时,该技术在山西左权天一煤业公司3102工作面进行了工业试验,结果表明其具有促使巷道围岩变形减小、巷旁支护效果显著等优点,取得了较好的经济技术效果。

某矿原切眼段切顶留巷围岩变形机理及防控技术

某煤矿21304工作面采用切顶沿空留巷技术,至安全回采留巷584 m时,为降低工作面排水成本,陆续对底板排水孔进行注浆封闭,从而导致原切眼段留巷迅速产生了较大变形。以上述问题为背景,对原切眼段切顶留巷围岩变形机理及防控技术进行了研究。结果表明:原切眼段留巷围岩变形受注浆封孔导致底板水压增大﹑积水导致底板吸水膨胀﹑支承压力降低区应力环境和巷道围岩完整性差等因素影响,其中底板排水孔注浆封闭导致底板水压升高是该段巷道变形的主要原因,巷道顶底板移近量以底鼓量为主,在此期间产生的底鼓量是顶板下沉量的2倍之多。提出了"重新疏通排水孔﹑加大支护强度﹑提高区域排水能力和矿压及排水量监测"等防控措施,有效控制了围岩变形,巷道卧底返修后能满足下一工作面使用要求。

矸石充填综采工作面沿空留巷技术

济宁三号煤矿6304工作面采用综合机械化固体充填采煤法,采空区采用矸石充填法管理顶板,为减少综采工作面掘进回采巷道,提高回采储量,实现2个临近工作面共用1条回采巷道,可对先采工作面运矸巷巷帮进行充填,实现后采工作面继续应用此巷道。结果表明:留巷稳定后,巷道平均宽度4.5m以上,巷道平均高度约为3m,满足了工作面安全生产的需要。

朱村矿膏体充填留巷技术

阐述了膏体充填开采留巷技术在焦作朱村煤矿回采过程中的应用,并通过矿压观测,总结得出留巷矿压显现规律,为煤矿充填开采生产提供了经验和方法。

深浅孔联合爆破切顶留巷围岩控制技术及应用

为解决淮南矿区深井砂岩直覆工作面切顶留巷后的围岩稳定性问题,首先,分析深浅孔联合爆破切顶留巷技术原理,采用深孔预裂爆破技术使基本顶断裂并垮落,同时采用聚能爆破技术对直接顶进行定向切割;然后,根据理论分析确定深浅孔联合爆破方案,并通过数值模拟方法分析未切顶、切直接顶及深浅孔联合爆破3种不同切顶工作面的应力分布特征;最后,在丁集矿1452(1)砂岩直覆工作面进行现场工业性试验。研究表明:深浅孔联合爆破切顶留巷围岩控制技术可以更好地阻断覆岩之间的应力传递,改善留巷顶板应力环境;在工作面推进方向,减小周期来压步距,来压强度平缓,在留巷巷道中,减小留巷上方悬顶长度,形成短壁梁,有效地降低了留巷围岩的应力,较好地控制了围岩变形。

软弱厚煤层“三沿”布置技术应用研究

软弱厚煤层工作面掘进回采巷道,通常采用沿底掘进,存在冒顶风险,且不易推广无煤柱开采。针对煤层厚度变化和煤层软弱的特点,提出一种“三沿”技术,即利用煤层顶板较为坚硬的特点,采用主动锚网索支护的方式进行回采巷道的“沿顶掘进”,使用定向预裂爆破技术实现切顶卸压“沿空留巷”,以及采用“主动锚网索+木垛+U型钢支架”的支护方式进行超前卧底形成超高巷道来实现煤炭最大程度的“沿底回采”。根据工作面开采动压影响和切顶卸压原理,在距离工作面不同距离范围内分别设计了6个阶段的动态支护参数。工程实践表明,沿顶掘进有利于巷道稳定和沿空留巷技术的应用,同时能够最大程度地回收煤炭资源。该技术解决了软弱厚煤层沿底掘进巷道支护困难、留设煤柱浪费资源等问题。

Technique of coal mining and gas extraction without coal pillar in multi-seam with low permeability

Aimed at the low mining efficiency in deep multi-seams because of high crustalstress,high gas content,low permeability,the compound 'three soft' roof and the trouble-somesafety situation encountered in deep level coal exploitation,proposed a new idea ofgob-side retaining without a coal-pillar and Y-style ventilation in the first-mined key pressure-relieved coal seam and a new method of coal mining and gas extraction.The followingwere discovered:the dynamic evolution law of the crannies in the roof is influenced bymining,the formative rule of 'the vertical cranny-abundant area' along the gob-side,thedistribution of air pressure field in the gob,and the flowing rule of pressure-relieved gas ina Y-style ventilation system.The study also established a theoretic basis for a new miningmethod of coal mining and gas extraction which is used to extract the pressure-relievedgas by roadway retaining boreholes instead of roadway boreholes.Studied and resolvedmany difficult key problems,such as,fast roadway retaining at the gob-side without a coalpillar,Y-style ventilation and extraction of pressure-relieved gas by roadway retainingboreholes,and so on.The study innovated and integrated a whole set of technical systemsfor coal and pressure relief gas extraction.The method of the pressure-relieved gasextraction by roadway retaining had been successfully applied in 6 typical working faces inthe Huainan and Huaibei mining areas.The research can provide a scientific and reliabletechnical support and a demonstration for coal mining and gas extraction in gaseous deepmulti-seams with low permeability.

基于安全高效支护结构体的堆喷技术研究与应用

针对煤矿井下作业环境的特殊性和现有支护技术的不足,提出了堆喷技术,确定了工艺参数,研发了堆喷外加剂(S2),揭示了S2强化堆喷料性能的作用机理,形成了一套完整的堆喷构筑矿用支护结构体的工艺方法,并应用于沿空留巷等工程实践。结果表明:(1)堆喷技术可以根据需要构筑支护结构体,不受空间断面限制,操作工远离危险区,安全高效控制围岩;(2)堆喷料潮拌及输料管路分段加水工艺,提前湿润物料,可以促进堆喷料水化作用、增强粘附性及和易性、降低粉尘和回弹率;(3)S2的促凝组分包括NaAlO_(2)、Al_(2)(SO_(4))_(3)、NaF、Al(OH)_(3)和快硬硫铝酸盐水泥(SAC-42.5),增粘抗裂组分为硅灰(GS)、聚丙烯纤维(JB),提高了支护结构材料的凝结速度和抗压强度,且具有微膨胀特性;(4)现场堆喷标准试件的单轴抗压强度测试结果为1天12.0 MPa,3天18.1 MPa,7天27.5 MPa,28天42.1 MPa,90天42.3 MPa,具有高强承载能力,且后期强度不倒缩,强度增长过程分为三个阶段:初期快速增长阶段(龄期0~14 d)、中期持续增长阶段(龄期14~28 d)、后期稳定阶段(龄期>28 d);(5)堆喷技术构筑巷旁隔离墙实现沿空留巷,拓展了矿用支护结构体的高效施工方法。

新型沿空留巷技术在综采工作面的研究与应用

介绍了新型沿空留巷技术在辛置煤矿的研究和应用,2-559工作面采用的新型沿空留巷技术,改变了以往预掘留巷方式,充分利用综采工艺,使用采煤机割煤留巷,减少了掘进巷道,解决了工作面生产衔接紧张局面,提高了资源回收率,经济效益显著,同时也为其他煤矿提供了借鉴。

采用沿空留巷新技术 提高矿井安全和效益

根据沿空留巷顶板岩层活动特点,采用水泥浇筑石墙与锚索支护技术维护巷道,不影响巷道的正常使用断面,不用再对巷道二次维修,极大降低了工人的劳动强度,提高了矿井安全和效益。

沿空留巷联合支护技术研究

基于巷旁支护前期的切顶作用以及后期支护体的高支撑力的要求,通过综合技术比较和经济比较,提出了一种将切顶支柱和间隔"编织袋"混凝土墙联合布置使用的方案。"编织袋"混凝土在充填采空区提供高强支撑力的同时可以有效防止采空区矸石冲击切顶支柱。工程实践表明,在采场顶板坚硬出现悬顶的中厚煤层中,该方案是一种理想的沿空留巷技术。

采煤工作面柔模混凝土沿空留巷实践

为了提升回采效率,结合高河煤矿实际情况,针对3号煤层E1302作业面开采情况,制定了柔模混凝土支护沿空留巷施工方案,可以显著提升煤柱回收率,具有较高的经济效益。

沿空留巷超前切顶加固技术及支护参数优化研究

为解决沿空留巷受到顶板上覆岩层分布不规律影响问题,提出了切顶卸压沿空留巷技术,利用数值模拟软件,对综采工作面切顶与未切顶情况下沿空留巷周边应力环境进行分析,确定了沿空留巷超前切顶加固技术方案。实践表明,切顶长锚索锚固力合格率超过95%,沿空留巷速度提高了10%~38%,工作效率大幅提升,达到了安全生产和降本增效的目标。