瓦斯灾害是煤矿安全生产的"第一杀手",瓦斯抽采是防治瓦斯事故的治本之策,而低透气性煤层是制约瓦斯抽采的关键因素.由于浅部资源逐渐枯竭,我国煤矿开采深度以每年10～30, m速度向深部延深,开采煤层表现出显著的"低煤层渗透性、高围岩地应力、高煤层瓦斯压力"特征.面对深部矿井煤岩复合动力灾害,单一采用地面井或者井下钻孔预抽等措施,在高地应力、低渗透性条件下难以取得较为理想的抽采效果,同时无法消除煤岩内部积聚的弹性应变能、降低采掘区域内地应力威胁,需结合有效的卸压增透措施才能满足复合动力灾害的治理需求.由此,研究一种既能满足煤层瓦斯快速抽采达标,又能达到降低煤层应力的技术手段,是煤矿科研工作者共同努力的方向.

为确定近水平层滑构造高侧压系数对上保护层开采保护范围的影响,以韩城矿区下峪口煤矿为工程背景,分析了不同侧压系数对被保护层垂直应力演化、弹性能分布的影响,理论分析得出保护层开采后在煤层走向上产生高地应力梯度,进而减小防突卸压保护角;采用数值模拟方法得出保护层开采条件下煤层走向防突卸压角随侧压系数增大而减小,工作面倾斜上、下方的防突卸压角基本不受侧压系数影响的规律.该研究可为矿井被保护层工作面布置及瓦斯治理提供符合矿井实际的科学依据,并对相似矿井保护层开采范围的确定具有借鉴意义.

为解决低渗透性中硬煤层顺层钻孔抽采半径影响范围较小、抽采效果较差等问题,研究了工作面顺层长钻孔超高压水力割缝技术.通过应力波效应研究了水射流破煤机理,分析了超高压水力割缝卸压增透原理,研制出工作压力达100 MPa的超高压水力割缝成套装置,实现了超高压状态下不退出钻杆的钻割一体化工艺和远程操作功能,考察了超高压水力割缝参数,形成了顺层钻孔超高压水力割缝工艺技术.现场试验得出:割缝钻孔平均单刀出煤量为0.32 t,等效割缝半径达1.51～2.08 m;割缝后钻孔瓦斯抽采浓度同比提高了1.44倍,瓦斯抽采纯流量提高了3倍,有效抽采半径为对比普通钻孔的3.6倍,钻孔施工时间缩短约30％,抽采达标时间缩短40％左右.应用表明,采用超高压水力割缝增透技术后,煤层的透气性明显改善,达到了快速卸压增透的目的.

为了研究深井无保护层开采条件的单一严重突出煤层煤巷条带区域瓦斯治理问题,运用FLAC3D模拟分析了底板巷道掘进时、工作面回采前后围岩应力分布特点,对采用底板巷穿层钻孔预抽煤层瓦斯时的巷道合理空间位置进行了研究,结果表明:预掘卸压底板巷布置在待掘煤巷正下方、法距8～15 m位置是合理、可行的.丰城矿区曲江煤矿213底板巷位于待掘煤巷正下方平均垂距9 m,巷道中心线两侧15 m范围煤层的钻孔瓦斯流量、透气性系数均有不同程度增加,缩短了抽采时间,有效的降低了煤与瓦斯突出危险;同时,穿层钻孔采用非等间距布置方式,节约大量钻孔工程、成本降低、缓解采掘接替紧张局面.

Coal and gas power risk was increased under the condition of high stress, high gas and low permeability of coal seam in deep mine, low permeability coal seam gas pre pumping was very difficult. Drilling enlarging by high-pressure water jet used high pressure water as the driving force to wash and peel the coal body in the drilling, it aimed to discharge the coal and release the gas in the coal seam quickly, the gas pumping efficiency was improved, the stress of coal seam was declined, and the goal of rapid pressure relief and permeability was achieved. It applied in some serious outburst rock cross-cut coal uncovering area, with drilling enlarging by high-pressure water jet technology, drilling equivalent get to 500~800mm after drilling enlarging, about 3~9 times of the original diameter, gas extraction concentration was 1~2 times higher than before, coal uncovering time was shortened by 1/3~1/2, the effect of field application was obvious.

The dynamic disasters of coal and gas outburst are serious in Fengcheng Coal Mining Area, the single B4 coal seam being mined is a gently inclined medium-thick seam featured by high gas pressure and content, loose and low gas permeability. In this paper statistical analysis was made on the characteristics and regularity of 186 coal and gas outbursts according to the gas occurrence features in this mining area; to counter to the increase of the dominant outbursts induced by stress with the increase of mining depth, the parting disaster treatment measures were proposed, the stereo gas drainage system was established and exploration was carried out on some new technological measures such as long-hole pre-splitting blast, long-hole drilling along roof strike, hydraulic reaming, hydraulic fracturing and so on, this thus provided theoretical guidance for the prevention and control of gas outbursts in this mining area.

In order to elininate the outburst danger of a mine seam gateway driving in the deep mine single serious outburst seam,the paper theoretically analyzed the outburst composite energy and mechanics features of the deep seam gateway and provided the pressure released and outburst prevention technology of the pre-heading floor rock roadway.The numerical simulation in combination with the actual Fengcheng Mining Area was applied to determine the pre-heading floor rock roadway should be located at 8 ～ 12 m underneath of the seam gateway to be driven.The practices showed that the pressure released and outburst prevention effect of the pre-heading floor rock roadway was remarkable,the max displacement of the surrounding rock was 4.1 cm,the partition cracking phenomenon occurred in the surrounding rock and there were four cracking zones generally.The initial gas flow of per meter borehole and the permeability coefficient of the seam could be 14.39 and 55.70 times higher than the insitu seam,the gas drainage density was improved by 5 times and the gas drainage volume of a single borehole was improved by 10 times.There was no over limit phenomenon occurred in the effective inspection index of the seam gateway,the driving speed of the seam gateway was improved from 40 m/month to 100 m/month,and the safety and rapid driving of the seam gateway was realized,and could provide important reference significances to the mines with the similar conditions.

In order to obtain coal and rock fracture behavior of different types crack under the compression state, this paper studied the influence of crack types to fracture resistance ability of coal and rock, and analyzed the initiation law of opening type crack and closed type crack based on fracture mechanics. The results show that the geometric parameters and load affect the initiation law of crack significantly. The characteristics of coal and rock fracture including different types of crack are different. The closer crack angle of coal and rock gets to 40 ~ 60 degree, the longer the length, and the smaller the coefficient of lateral pressure, the greater curvature radius of open type crack. The smaller crack surface friction coefficient of closed type crack, the smaller fracture stress of crack,and the easier the coal and rock burst. The method for estimating degree of coal and rock burst is put forward according to the types of crack based on the research results.

针对深部开采矿井冲击地压和煤与瓦斯突出复合型动力灾害愈发严峻的问题,分析了动力灾害发生条件及其属性分类.以千米深井口孜东矿为例,对其首采区13-1煤层同时开展突出和冲击两种动力灾害属性鉴定及111303工作面重点防冲区采前预测,按区域措施先行、局部措施补充原则试验了“瓦斯预抽达标、注水降冲有效”及支架工作阻力在线监测、钻屑指标法预测危险、强化支护、控制回采速度等综合防治措施,生产实践表明,这些措施有效防治了应力主导型动力灾害,研究成果对类似生产矿井具有指导与借鉴意义.

Study was carried out on the evolution and distribution regularity of floor stress field in the extraction of the medium-or large-interval upper protection seam by using theoretical and the numerical simulation method,it was found that the gob floor rock strata of the upper protective seam by long-wall mining assumed a concave pressure-relief shell in dip direction and an O-shaped pressure-relief shell on strike plane,the pressure-relief angle was the minimum at the corner angle near its starting cut or terminal line,the pressure-relief effect in the middle of the bottom protected seam was better than that on its two sides,i.e.the drainage radius in the middle of the protected seam was larger than that on its two sides;the pressure-relief zone of the protected seam in strike lagged a certain distance behind the working face of the protective seam,so this theoretical result can be used to guide the gas drainage from protective seam by boreholes.

Study was carried out on the evolution and distribution regularity of floor stress field in the extraction of the medium-or large-interval upper protection seam by using theoretical and the numerical simulation method,it was found that the gob floor rock strata of the upper protective seam by long-wall mining assumed a concave pressure-relief shell in dip direction and an "O"-shaped pressure-relief shell on strike plane,the pressure-relief angle was the minimum at the corner angle near its starting cut or terminal line,the pressure-relief effect in the middle of the bottom protected seam was better than that on its two sides,i.e.the drainage radius in the middle of the protected seam was larger than that on its two sides;the pressure-relief zone of the protected seam in strike lagged a certain distance behind the working face of the protective seam,so this theoretical result can be used to guide the gas drainage from protective seam by boreholes.

Mine into the deep mining, the power disaster occurs mechanism more complex features fuzzy disasters and hazards common. Outburst and rock burst and other disasters are common differences, the use of traditional coal seam outburst hazard identification method has limitations. According to the kilometers deep test area, the individual indicators law 13-1 coal seam the outburst hazard identification,13-1 coal seam first mining area were identified as non-prominent seam. While outburst identification test area seam burst tendency identification,13-1 coal seam has a strong burst tendentious. The test mine disaster prevention should also consider bumping prevention and control not only consider the gas control. Project research results have important reference conditions similar to mine.

To guarantee the drilling construction safety of floor and enhance the effect of relieved gas drainage in protected seam,based on the status of drilling construction and gas drainage of that the protective layer is in serious outburst danger during the mining process of the upper protective layer,taking Qidong Mine protective layer mining as an example,by using the rock pressure and elastic mechanics theory and combined with FLAC3D numerical simulation software,the reasonable drilling hole protected seam position and construction time are studied during the upper protective mining.The results show that the most reasonable and safety position of drilling hole in coal seam of protected No.9 coal is at the place that the delay plane distance is from the protected coal 16 to 26 m.

Test mine is a large modern mine, the 13-1 coal-seam original permeability coefficient was low, gas pressure and content were higher, coal seam outburst danger of serious, directly extracting coal gas is difficult. Using a new type of high pressure water jet reaming technology, can achieve the expansion of borehole diameter, increase coal seam exposed area and pressure relief range, thereby improving the coal seam permeability, increased coal seam drainage radius. Investigated on the basis of determination of the original coal seam gas pressure and content of the coal extraction radius after the hydraulic reaming. Provide the basis for the seam of the test area borehole design

The gas extraction radius by boreholes is mainly related to the factors such as the coal-seam gas content,the air permeability coefficient,the diameter and negative pressure of gas extraction borehole,the gas extraction purpose,time and so on.A certain results can be obtained for the coal seam having better permeability and pressure measuring condition with the traditional determination method for gas extraction radius,but its efficiency is rather low;when the coal seam has poor permeability,the success rate of the measurement is extremely low and its applicability is poor.For this reason,direct measuring method was used for the measurement of dynamic gas extraction flow from boreholes on the basis of the coal-seam gas content being known,the extraction rate was determined according to the extraction purpose,and then the extraction radius by the borehole at different extraction time was also determined.The practice indicated that this method is practical and easy to generalize.

In Xinji Coal Mine under complicated geological conditions, regional faults. Experimental zone for near coal seam group mining(6-1,7-1,7-2,8 seam), The objective conditions with protective layer . The minefield of soft broken coal seam, Soft layered coal firmness coefficient f = 0.18. In the test area of 210601,210603 6-1seam protective layer mining face during the period, there were 8 abnormal gas dynamic phenomenon, To the coal mine safety production brought hidden trouble. On the basis of dynamic phenomenon occurring phenomenon, analysis of the dynamic phenomena, combined with the test area actual situation, summed up the6-1coal power causes, for guiding the 6-1safety mining and provide a theoretical basis, has important significance.

The test mine is a large modern mine,its 13-1 coal seam has low original permeability coefficient,higher gas pressure and content,and serious outburst hazard,so the direct gas drainage from this seam is more difficult.The use of the new hole enlargement technology by high-pressure water jet can achieve the goal of enlarging the hole diameter,increasing the exposed area of the coal seam and pressure releasing range,and thereby improve the permeability of the coal seam and increase the gas extraction radius from the seam.On the basis of measuring the original gas pressure and content of the seam,investigation was made on the gas extraction radius from the seam after hole enlargement by using the reduction method of gas pressure and content,this thus provided a basis for the design of gas extraction holes in the test area.

In this paper, study was carried out on the control features of the regional and mine field structure based on the actual coal-bed gas geological data and by using the coal-bed gas geology theory; statistical analysis on the outburst data was made and the characteristics of coal and gas outburst in Pinghu Coal Mine were summarized; analysis was carried out on the influence and control effect of the regional evolution, the occurrence depth of coal seams, the lithological characters of roof anf floor rock, the coal seam thickness and its change, the nature of coal, the mine structure and mining factors upon coal and gas outburst. The analyzing results showed that the lithological characters of roof anf floor rock, the coal seam thickness and its change and the mining factors had significant influence on coal and gas outburst, and the fault structure controlled the occurrence and distribution rule of outburst. Therefore, the dangerios regions of outburst can be divided according to the coal-bed gas geological conditions, thus better directing the prevention work of coal and gas in a coal mine and providing an analyzing method for regional coal and gas outburst control in coal mines with similar conditions.

With gas coal based on different mechanical characteristics and stress state, the face of the scope of single -hole depth predicted peak stress and stress distribution non-unimodal outstanding drilling method based on prediction theory, combined with Huainan mining area of deep coal mining Xie yi C15, Xin zhuang-zi 134 coal, Ding ji 11-2 Coal Mine Gas Outburst Coal typical mechanical properties and stress field evolution, innovation and test drilling Outburst Prediction Methods and success indicators. The study of deep mine coal and gas power has an important reference for disaster prediction.

常用的最大钻屑量指标仅仅反映了某一点的应力情况,而动力灾害的发生主要是由于应力状态的突然改变产生的,也就是应力变化梯度的大小是决定灾害发生的主要原因.因此,提出了考察应力变化情况的新的钻屑量指标,即钻屑增量变化指标.结合采掘工作面支承压力的分区特点,在整体把握钻屑增量指标的前提下,着重把握2个拐点处量值的变化.理论分析和实践证明,采用钻屑增量指标,再辅以最大钻屑量指标,则可更好的反映工作面的应力变化情况,从而能够更为准确的预测工作面灾害发生的可能性.