综采工作面顶板突水的分析与控制外文文献翻译

英文原文Analysis and control on anomaly water inrush in roof of fully-mechanized mining fieldPeng Linjun a,b,c, Yang Xiaojie a,c, Sun Xiaoming a,ca School of Mechanics and Civil Engineering, China University of Mining & Technology, Beijing 100083,Chinab Academician Pioneering Park, Dalian University, Dalian 116622, Chinac State Key Laboratory of Geomechanics and Deep Underground Engineering, China University of Mining &Technology, Beijing 100083, ChinaAbstract: Caving of mine roofs from water inrush due to anomalous pressure is one of the major disasters and accidents that can occur in mines during production. Roof water inrush can trigger a wide range of roof collapse, causing major accidents from breaking roof supports while caving. These failures flood wells and do a great deal of damage to mines and endanger mine safety. Our objective is to analyze the anomalies of water inrush crushing the support at the #6301 working face in the Jisan Coal Mine of the Yanzhou Mining Group. Through information of water inrush to the roof, damage caused by tectonic movements, information on the damage caused by roof collapse and the theory about the distribution of pressure in mine abutments, we advice adjusting the length of the working face and the position of open-off cut relatively to the rich water area. In the case of anomalous roof pressure we should develop a state equation to estimate preventive measures with “transferring rock beam” theory. Simultaneously,we improve the capacity of drainage equipment and ensured adequate water retention at the storehouse.These are all major technologies to ensure the control and prevention against accidents caused by anomalous water inrush in roofs, thus ensuring safety in the production process of a coal mine. Keywords: Roof;Water inrush pressure;Anomaly;Analysis;Control;abstract;Caving1. IntroductionBoth domestic and foreign investigators pay considerable attention to coal mine pressure anomalies and obtained various results. However, because of the complexity of anomalous pressure, as well as the mutability of surrounding rock conditions caused by caving, a number of difficulties are encountered in building an exact and systematic mathematical mechanical model. Furthermore, because geological conditions differ considerably in various parts of a coalfield and the reality is very complex, we must therefore adopt a number of different measures and methods to predict and monitor geological conditions, given that many methods have their own limitations. The process of calculation for the support of the surrounding rock summarizes this mechanism, thus perfecting the method of forecasting and monitoring, forming a feasible and efficient system for safety in production, ensuring security and efficiency at coal mining faces. Coal mine pressure anomalies, showing up in fully-mechanized caving fields, as dynamic phenomena interfering with safe production in coal mines, refer to anomalous rock pressure occurring under special conditions. When the mechanical balance is broken in a coal (rock) body around a coal mining field, it usually shows up as damage to the support system, as a crushed or sinking roof level or as severe spalling, before the occurrence of risky leaks and ultimately coal and gas outbursts. When rock pressure appears as anomalies, it often results in damage to equipment, significant loss of coal resources and forming simultaneously significant security risks, which in coal mines may lead to devastating consequences. In recent years, a large number of mine pressure anomalies occurred in fully-mechanized caving mines in Chinas Yanzhou and Xuzhou mining areas, causing considerable economic losses to coal companies. Therefore, further systematic study of the structure and movement of the overlying rock in fully-mechanized caving mines, may reveal the behavior of mine pressure anomalies, discover the conditions under which these anomalies occur, find methods to forecast and prevent them, in order to achieve safety and efficient production. 2. Coal seam conditions and structure of overlying rockThe Jisan Coal Mine is located in a suburb of Jining city, where the mining area is about 110 km2. Geological reserves of 880 million tons, industrial reserves of 800 million tons, and recoverable reserves of 530 million tons have been confirmed. The #3 coal layer has 400 million tons of coal, accounting for 75.5% of recoverable reserves. These coal strata are part of the Permian Shanxi Formation and the Carboniferous Taiyuan, with eight layers of locally accessible coal and an average thickness of 10.44m. Themajor recoverable coal is found in the 3up, 3down layer with an average thickness of 6.21 m. The geological condition of the mining area is a simple middle structure. The main northesouth normal fault is apparently regular, with most of the east rising and the west falling. Also, there are faults showing the development of eastewest with the east and southeast dipping gently, generally at slopes less than 5, and gentle changes in their wrinkly trend. Deeper dips toward the west and southwest have slopes between 5 and 9. The mine is expected to discharge 516m3/h of coal water. The key layer, affecting anomalies in water inrush from the roof in the working faces, is the following layer of the second rock beam, i.e. M5 siltstone, 6.5 m thick, and a detailed roof rock structure is shown in Table 1.Table 1.Profile of cave mining face of a stope roof.No.LithologyThickness of layer(m)Depth（m）Roof structureThickness（m）StepC0 C。11.20639。4.20。3.80M5。6.50FollowinglayerThesecondrockbeam16.560 20M4。10.00Supportlayer。M3。9.00FollowinglayerThe firstrockbeam28.082 27。M2。19.00SupportlayerContinued Table 1。M17.00Immediateroof7.0M7.066853. Analysis of roof water inrush pressure causing anomalous crushing supportsThe main reasons for the five water inrush accidents which flooded the #6301 working face of Jisan are twofold: 1) the overlying stratum contains water; according to drilling data from the surface and audio-frequency electrical penetration at this working face, there are four water-rich areas above the face, located at both ends and the middle. Moreover, water-rich Jurassic strata are found at 193 m above the roof of 3down coal seam. 2) Large area of main roof caving, break lines extending to overlying aquifers, as well as faults in the working face; with the initial face exposed, water is showing up along the fault plane; with working face advancing, the exposed fault length also increases, resulting in a continuously increasing water inrush. Therefore, the break lines communicate faults to the water-rich fault zones as shown in Fig. 1.Fig. 1 #6301 working face flooding accident.3.1. Reasons of roof water inrush anomalies crushing support1) The support force resisting pressure is insufficient against roofconvergence (support is working under a given deformation status).2) Pressure on the roof rock beams is excessive; support load bearing capacity cannot meet the conditions to main roof convergence(to the given deformation status), i.e., roof convergence exceeds the maximum value of nominal yield of support.3.2. Conditions of occurrence of roof water inrush anomalies crushing supports1) With progressive face advance, the overlying rock layer is in communication with the water-rich sandstone layer which causes increase in the thickness of simultaneously moving main roof, decrease in main roof span length, and increase in roof pressure;2) The depth of roof break lines from the front wall increases, causing decrease in the thickness of immediate roof; 3) The immediate roof is thin which increases the roofefloor convergence; 4) The main roof is, in general, very thick, and it is easy to form a large cantilever beam space, causing an impact on the main roof dynamic pressure when roof caving.3.3. Structural model of roof water inrush caused by anomalies1) In a “given deformation” condition, the roof convergence is determined by the position of a free-falling rock beam contacting the floor in the gob shown in Fig. 2, i.e., hT=hA。Where (1) （2)Fig. 2 Structural model of a water inrush accident of a fully-mechanized caving mine.2) Relationship between roof water inrush and movement of overlying rock strataIn a case of a given open-off cut position and the length of the working face, the broken rock strata may reach to rock aquifer, especiallywater-rich region, with progressive face advance . When the aquifer is parallel to the seam, as in Fig. 3, the possibility of flooding and related parameters of the model can be determined.Where L is the advance step at the working face; Lo length of working face; LB water-rich area in rock stratum of water open-off cut location; Lh center of breaking rocks (breaking arch) cut from the bottom position; h height of broken rock stratum; H height of water in rock stratum; and B width of water-rich zone.Fig. 3 Forecasting graph of possible permeability.3.4. Support conditions in #6301 working face and the actual effects of roof control during floodAccording to the analysis of the first roof water inrush accident,the pressure crushed the support of the #6301 working face, when it advanced 613 m, increased the volume of the water at the face to 50m3/h, flooding the coal mine and the gob area. With the working advancing, a big bang above the face was heard (the sound of main roof breaking) and the volume of water at the face increased to 327 m3/h, with a maximum volume of 350 m3/h. This caused some of the temporary electrical stations to be inundated and work at the face was forced to stop. The roof suddenly broke and sunk, the supports of #11-67 were crushed at the face. Whenwater suddenly flooded the working face and the amount of water increased considerably, the capacity of the pump of the integrated drainage system was insufficient, resulting in an amount of water 2 m deep at the face. At the start, large volumes of water were discharged in the roadway. Slurry water, coal and other debris flooded into airtight wall, closed the outlet, and appeared dangerous situation due to high water pressure. Peak discharge lasted five days, the water inflow continued for seven days, and the entire water gushing process lasted 41 days. The position of water inflow is at the location of main roof periodic caving. In a given geo-mining condition in this case, structural parameters are calculated by using structural mechanic models to assess the support requirement inthe following.When the mining depth is about 700 m, the coal seam is 7 m, the length of the working face 200 m and after 200 m advance, the front distance of SM is about 20 m. From Eq. (3), we have the following results:The breaking distance from the front wall of face at the lowerrock beam is: (3)The lower limit of support capacity: (4)The upper limit of support capacity: (5)The lower limit of support resistance: (6)The upper limit of support resistance: (7)Under conditions of roof water inrush when the working face is stop, the largest roof convergence (hd = 0) (8)The current support working resistance is RT=6200 kN, maximum convergence is 3max ? 1000 mm. Obviously, the support resistance (RT=6200 kN) is less than the “given deformation” of the maximum resistance force (RT=9975 kN) required. As a result, the support system will work in a state of “given deformation”. If there is no floor coal left (hd=0) or no measures are taken to speed up the face advance, collapse of the face supports will occur and result in more serious flooding hazard. If the advance of face is fast, i.e., let S0 ? 0, the convergence of face is controlled in the range of hA=0.8M, collapse of the face supports can be avoided as long as the cutting height is adequate.4. ConclusionsThe anomalous pressure in the working face and water inrush ccurred, caused by geological factors first, the overburden aquifer s the main factor. Strengthening of forecast technology and accurate rediction of the “two zone” developed height is needed. ccording to a detailed hydro-geological report, a degree of ommunication between a working face and the amount of water n rock layers needs to be determined. We can draw the following onclusions:1) Before main roof periodic caving occurs, begin using no top coal aving advance method, until the main roof caving in order to ake sure that the main roof has enough cushions to reduce the height of the ultimate convergence.2) Before main roof caving, ensure the largest cutting height. Support must be maintained as long as possible at a high level collapse of the face supports in order to maintain the maximum leg convergence to reduce the possibility of support closure.3) In a case of given length of the face, the scope of the overlying strata, including the thickness of both the immediate and the main roof as well as the height of the permeable fracture zone. The span of main fall and periodic caving location may fall intothe fractured zone of the aquifer under the action of gravity.4) Information on the distribution of the abutment pressurefocused on the width caused by “internal stress field” around the walls of the working face.5) Reasonable selection and transformation of support. In order to prevent the collapse of supports due to roof caving, we can select proper support and increase the caliber of safety valves to adjust the rapid yield valve requirement for safe working of the support.In short, scientific management, overall arrangements, organizing highly efficient production and accelerating the speed of face advance are required. Rock strata failure and movement needs a time period, we can accelerate face advance where pressure anomalies may appear, then the roof falls may occur in the gob to avoid occurrence of pressure anomalies.中文译文综采工作面顶板突水的分析与控制彭林俊a,b,c 杨晓杰a,c 孙晓明a,ca 中国矿业大学（北京）力建学院， 中国 北京 100083；b 大连理工大学学者创业园，中国 大连 116622；c 中国矿业大学（北京）岩土力学地下工程国家重点实验室，中国 北京 100083；摘要：压力异常造成的顶板突水是煤矿生产个过程当中造成灾害的主要因素之一。顶板突水会引起大面积的顶板垮落，在顶板破碎支撑开采中会造成严重的灾害。突出的水会造成淹井事故并对矿井安全造成危害。本篇旨在分析兖州煤业集团济宁三号矿6301工作面的异常突水对支护的影响。通过对地质运动造成的顶板突水以及根据矿业理论顶板垮落的危害的信息分析，我们建议参考富水区调整工作面长度和开切眼的位置。若遇到顶板压力异常的情况，我们应该根据“砌体梁理论”建立。同时改善排水系统的排水能力并保证水仓有适当的存留量。通过这些，我们就能对顶板水突出做好防治的工作，进而确保煤矿的安全生产。关键词：顶板；突水压力；异常；分析；控制1. 引言国内外有诸多学者对矿压做了大量研究并得出了丰硕的成果。但是，矿压的的不规律性和由开采引起的围岩条件的多变性使得建立一个系统、科学、准确的力学模型变的非常困难。此外，现实中一块煤田的不同区域的地质条件也不尽相同，非常复杂。同时考虑到各种研究方法的局限性，所以我们必须用很多种不同的方法去预测和检测地质条件。对围岩支护数据的计算分析，完善了预测和检测方法，从而形成了一个能确保工作面安全，高效生产的合理的检测、预测系统。综采放顶煤工作面的矿压显现一般是在压力异常的情况下发生的，以动态的形式影响工作面正常、安全生产。围岩的力学平衡被破坏，从而导致支护系统失稳，顶板破碎坍塌，最终引发煤与瓦斯突出。矿压显现的不规律不仅破坏工作面设备，造成煤炭资源的损失，而且会威胁到人的生命安全，甚至有可能引发一场灾难。近些年，在兖州和徐州矿区的很多矿井出现冲击矿压，给煤矿企业造成了很大的经济损失。因此，对综采工作面围岩结构和运动的近一步研究，可以揭示矿压显现的规律性，从而找到在采煤过程中预防或防止冲击矿压的发生的方法，以达到安全高效生产的目的。2. 煤层地质条件以及上覆岩层结构在位于济宁市郊区济三煤矿，矿区面积约110平方公里，地质储量为8.8亿吨，工业储量8.00亿吨，可采储量5.3亿吨。3号煤层储量4亿吨，占整个矿井可采储量的75.5%。这些煤层是二叠系山西组和石炭系太原组的一部分，共有八层煤，平均厚度为10.44米。主要可收回煤炭是3上，3下层，平均厚度为6.21米。矿区中央是一条南北走向的大断层，造成东面地势上升，西面地势下降。另外还有一些东西走向的小断层。在煤田的东面和东南方向是比较平缓的，大部分煤层倾角小于5，在有褶皱的地方角度有比较平缓的变化。较深的向斜结构向西和西南方向延伸，角度在5到9之间。矿井预计排水量516m3/h。关键层是地表以下第二岩梁，即M5的粉砂岩，厚6.5m。影响着工作面顶板的突水，详细顶板岩石结构见表1。3. 水引起的主要支护系统破坏分析济三矿曾发生5次水淹6301工作面的事故，其主要原因分为两方面：（1）在上部岩层中有含水层；据钻井和工作面音频探测，发现地表有四个水积聚区，分别在煤层所对应地表的两端和中间。此外，在3下煤层顶板的上方193m处发现有含水丰富的侏罗纪地层。表1 工作面垮落岩层概况序号岩性岩层厚度（m）深度（m）顶板结构最大厚度（m）StepC0 C。11.20639。4.20。3.80M5。6.50底板第二关键层16.560 20M4。10.00顶板。M3。9.00底板第一关键层28.082 27。M2。19.00顶板。M17.00直接顶7.0M7.06685（2）大面积老顶冒落，裂隙带和工作面断层延伸到上覆含水层。当工作面推进过程中，刚刚接触断层时，水沿断层缓慢流下来。随着工作面的不断推进，断层暴露长度也随之增加，造成工作面持续突水。由此得出，裂隙带是连接富水断层和断层之间的纽带。如图1所示。图1 6301工作面突水事故3.1.顶板突水造成支架受损的原因（1）顶回转时，支架的工作阻力远远不够的（支架只能在一定变形范围内才能正常工作）。（2）板的压力过大，支架不能适应老顶的回转（在一定变形范围内），也就是说，老顶的回转是造成支架损坏最主要的原因。3.2.顶板突水损坏支架的条件（1）作面的不断推进，上覆岩层与含水砂岩导通，使得工作面整个的上覆岩层密度增加，顶板压力大幅增加，老顶垮落