綜采放頂煤采煤工作面深部開采發(fā)生事故時巖爆危險性分析外文文獻(xiàn)翻譯

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Analysis on rock burst danger when fully-mechanized caving coal face passed faultwith deep mining Chen Xuehua a, Li Weiqing b, Yan Xianyang b aCollege of Resources and Environment Engineering, Liaoning Technical University, Fuxin, China bDongtan coal Mine, Yanzhou Coal Mining Company Limited, Zoucheng, China Abstract When fully-mechanized caving face passed fault, rock burst accidence easily occurred. The SOS microseismmonitoring system was applied to monitor the microseismic activities all time occurred in the coaland rock mass near the fault area. Variation features of microseismic energy releasing and microseismicfrequency were analyzed. Numerical simulation method was used to research the abutment stress distributionwhen coal face passed fault, which was compared with microseism occurrence rules. When thecoal face approached to fault, the abutment stress increases gradually, so the high stress would accumulatenear the fault region. When the coal face left fault, the abutment stress decreased. The SOS microseismmonitoring results showed that microseismic activity in the fault area had a high instability.When the coal face neared to the fault, total energy value and frequency released by the microseism steadilyincreased. The maximum energy peak value also had the tendency to rapidly increase. Before thestrong shock occurred, there was a period of weak seismic activity. The weak seismic activity showedenergy accumulation for strong shock, which can be used to forecast the danger of rock burst. Keywords:Rock burst;Microseism monitoring system;Fault;Numerical simulation  1.Introduction The equipment will be damaged, and people will be injuredwhen rock burst occurs, which is one of the biggest disasters tomine safety. With the expansion of mining and tunneling, the conditionof mining face will be complex, the mining activity in thecoal pillar and adjacent to coal pillar is inescapability. During themining progress in deep coal seam, influenced by the fault structure,the mine pressure appears very violently around the excavationface, the sound of mine quake becomes larger, and the numberof mine quake becomes more and more. Research on the rock burstoccurrence rule under the complex geological structure is verynecessary to safety production. The domestic and oversea scholars (Su and Li, 2008; Lu et al.,2008; Li et al., 2008a,b,c; Lu et al., 2007; Gou et al., 2007; Jianget al., 2006; Dou and He, 2004; Song et al., 2004; Caim Kaiserand Martin, 2001; Meng et al., 2001; Huang and Gao, 2001; Panet al., 1998) have studied the mechanism of fault activity inducingrock burst, and the microseismic law of rock burst portent. Theslide destabilization characteristic of surrounding rock, the stressdistribution and change rules, and rock burst occurrence mechanismwere researched by the viewpoint of the fault upper walland lower wall, coal seam roof and floor, and fault fractured zoneand coal mechanics character in the relevant document. The researchon rock burst danger of fully-mechanized caving coal facepassed fault is relevantly less.The No. 14310 coal face passing the No. NF6 fault in the Dongtanmine was acted as research object. The relevant mathematicalmodel was used to research the rock burst mechanism induced bythe activity of regional surrounding rock. Microseismic law of coalface passed fault was explored, which can guide the forecast andprevention of rock burst. 2.Microseismic activity monitoring and change rules in faultregion when coal face excavated 2.1. Change rules of microseismic hypocenter The Polish SOS microseismic monitoring system was used in theDongtan mine, and the microseismic activity was monitored andlocated in real time. The change of microseismic hypocenter positionand energy was recorded when the coal face passed the No.NF6 fault. The monitoring result about concentrative and violentdistribution of microseismic hypocenter was analyzed. Illustrated as Fig. 1, all kinds of the points showed microseismichypocenter position, the different shapes showed different microseismicgrades, and the black short line showed the excavationposition of coal face. According to the monitoring result, the microseismichypocenter changed along with the excavation progress. Inthe vertical section, the hypocenter changed obviously. When thecoal face was far from the fault, the excavation was little influenceon fault activity, and the microseismic hypocenter mainly distributedin the front of coal face and on the goaf. In July 26, 2010, the distance of coal face far from fault was62 m, the mine pressure emergence near coal face enhanced, thetimes of microseismic occurrence increased obviously, but themicroseismic grade was small. At this time, microseismic beganto appear near fault, which showed the fault activity was influencedby the coal face excavation (see Fig. 1a). Fig. 1. Distribution change of microseismic hypocenter along with coal face excavation in vertical section. Along with coal face excavation, microseismic activity wasmore and more obvious, hypocenter point concentrated on thehard rock seams above the main roof and near the fault (seeFig. 1c and d). In August 25, 2010, the distance that coal face leftfault was 80 m, microseismic occurrence was not influenced byfault, microseismic times reduced, microseismic position still beganto distribute in the front and goaf of coal face. According tothe microseismic monitoring result, there was rock burst dangerin the region near the fault under the excavation disturbance. 2.2. Changes of microseismic total energy and microseismic times According to the excavation progress, changes of microseismictotal energy and microseismic times were drawn as Fig. 2 duringthe period of coal face passing the fault. Since July 25, when the distance of coal face far from fault wasabove 60 m, microseismic times obviously increased. But microseismictotal energy little changed, and microseismic grade wasmainly small. After August 5, 6, high energy microseismic beganto appear, energy changed violently, which presented two rules:Firstly, microseismic energy undulated on a special level, but theamplitude difference between maximum energy and minimum energywas big. Secondly, before strong shock occurred, the frequencyand grade of microseismic activity had the decreasetendency. After strong shock occurred, microseismic usuallyturned to low energy shock. So the low energy shock showed thetendency of energy accumulation for strong shock occurrence.After August 24, the changes of microseismic energy were notinfluenced by the fault structure. (a) Changes of microseismic total energy (b) Changes of microseismic times Fig. 2. Changes histogram of microseismic energy and times during the coal face passing fault. 3.Mine pressure emergency near the fault under the influenceof excavation 3.1. Numerical simulation model The mining depth was above 600 m, so the uniformly distributionload acted on the upper boundary of model was 12.86 Mpa(Zhu et al., 2007). X direct displacement of model left and rightwas 0, and X direct displacement and Y displacement of model bottomwas 0 (see Fig. 3). Material constitutive relation was Mohr–Coulomb. The rock seam properties (see Table 1) referred to theNo. 49 geological borehole of the No. 14310 coal face in Dongtanmine. The fault mechanics property was referred to the relevantdocument (Zhou et al., 2006; Wang et al., 2003; Li et al., 2008a,b, c). Fig. 3. Numerical simulation model. 3.2. Fault influence on abutment stress The coal face excavated from fault lower wall to fault upperwall, when the different distance between coal face and faultrespectively were 80 m, 65 m, 40 m, 20 m, _5m, _30 m, _70 m,_100 m, the different abutment stresses distribution was illustratedas Fig. 4, and the peak value of different abutment stresseswas listed in Table 2. Table 1Rock seam properties of model. Table 2Peak value of abutment stress. When the distance between coal face and fault was 80 m and65 m, the two curve of abutment stress ahead of coal face werebasically superposition, so fault influence on abutment stress wasvery small. Numerical simulation results showed that in the coalbody ahead of coal face, stress peak value reached to 53.37 MPa,stress concentration factor reached to 3.42, the distance of stresspeak value far from coal wall of coal face was 24.2 m, and the stressinfluence scope was above 50 m. On-situ observation results indicatedthat the distance of stress peak value far from coal wall ofcoal face was more than 2–3.5 times of excavation coal height,the stress influence scope was 40–60 m, and stress concentrationfactor was 2.5–3 (Qian and Shi, 2003). The above two researchresults were similar, which explained that numerical simulationmodel was reasonable. Fig. 4. Distribution of abutment stress. Along with the coal face approached to fault, the fault influenceon abutment stress enhanced, and the stress peak value graduallyincreased. When the distance between coal face and fault was40 m, stress peak value reached to 70.84 MPa, stress concentrationfactor reached to 4.54, the distance of stress peak value far fromcoal wall of coal face was 25.2 m. When the distance between coalface and fault was 20 m, stress peak value rapidly reached to90.21 MPa, stress concentration factor reached to 5.78, the distanceof stress peak value far from coal wall of coal face was20.12 m. After the coal face left fault, the stress in the coal bodygradually decreased, for example, the distance of coal face left faultwas 30 m, stress peak value decreased to 74.81 MPa, and when thedistance was 50 m, peak value was 52.03 MPa, which was similarto normal excavation. Fig. 5 illustrated distribution nephogram of abutment stresswhen there were different distances between coal face and fault.When the distance of coal face approached fault was 15 m, therewas obviously stress concentration (see Fig. 5a) near the fault.When the distance of coal face left fault was 20 m (see Fig. 5c), rockseams near the fault were mostly destroyed, so the stress was little. Fig. 5. Distribution nephogram of abutment stress with different distances between coal face and fault. 4.Conclusions (1) When the fully-mechanized caving coal face with deep miningand big excavation height passed fault, several strongshocks occurred, which indicated that the great scope of rockand coal seams fractured and destroyed under the action ofabutment stress and fault tectonic stress, there was rockburst danger near the fault region. (2) Microseismic activity had obviously rule. When the coal faceexcavated normally, microseismic energy undulated on aspecial level. On the special conditions, before strong shockoccurred, the frequency and grade of microseismic activityhad the decrease tendency. After strong shock occurred,microseismic usually turned to low energy shock. So thelow energy shock showed the tendency of energy accumulationfor strong shock occurrence. (3) When coal face approached to fault, the abutment stress onthe front of coal face obviously increased, so the rock burstdanger near the fault was bigger. (4) Under the influence of coal face excavation, fault had thepossibility of instability and slippage, which was becausein the fault region, microseismic intensity obviouslyincreased, and most of microseismics occurred in the roofof coal seam. These rules can be used to forecast rock burstdanger.  綜采放頂煤采煤工作面深部開采發(fā)生事故時巖爆危險性分析 Chen Xuehua a, Li Weiqing b, Yan Xianyang b a 資源與環(huán)境工程學(xué)院，遼寧工程技術(shù)大學(xué)，阜新，中國 b東灘煤礦，兗州煤業(yè)股份有限公司，山東鄒城，中國 摘要 綜放工作面采煤通過斷層時，容易出現(xiàn)巖爆事故。 SOS微震監(jiān)測系統(tǒng)用于監(jiān)視所有的時間在煤巖體和斷層附近地區(qū)發(fā)生的微震活動，對微震能量釋放和微震頻率的變化特征進(jìn)行了分析。數(shù)值模擬方法被用來研究當(dāng)采煤工作面支承壓力分布通過故障時的模擬數(shù)據(jù)，這是與微震的發(fā)生規(guī)律相比較。當(dāng)工作面將要發(fā)生事故，支承壓力逐漸增大，因此，此時高應(yīng)力會積累斷層附近地區(qū)。當(dāng)采煤工作面經(jīng)過斷層，支承壓力下降。 SOS微震監(jiān)測結(jié)果表明，在故障區(qū)的微震活動有一個高的不穩(wěn)定階段。當(dāng)工作面接近斷層，微震釋放的總能量值和頻率不斷增加，支架支撐強(qiáng)度的最大能量峰值也有迅速增加的趨勢。強(qiáng)烈的沖擊發(fā)生之前，有一個微弱的地震活動期。弱地震活動表現(xiàn)出強(qiáng)烈的沖擊能量積累，它可以用來預(yù)測巖爆的危險。 關(guān)鍵詞：巖爆，微震監(jiān)測系統(tǒng);故障;數(shù)值模擬  1 介紹 巖爆發(fā)生時，采煤設(shè)備將被破壞，工作人員容易受到傷害，這是煤礦安全的最大的災(zāi)害之一。采礦和隧道的逐步擴(kuò)大，采煤工作面的條件將是復(fù)雜的，在煤柱附近的采礦活動是不可避免的。在深部煤層斷裂構(gòu)造的影響，開采進(jìn)度，礦山壓力出現(xiàn)非常猛烈的開挖面周圍，礦震的聲音變得更大，礦震的數(shù)量越來越多。復(fù)雜的地質(zhì)結(jié)構(gòu)下的巖爆的發(fā)生規(guī)律的研究對于安全生產(chǎn)是非常必要的。 國內(nèi)和海外的學(xué)者研究了斷層活動誘發(fā)巖石的機(jī)制爆裂，叫做巖爆前兆微震法。圍巖的應(yīng)力分布和變化規(guī)律，從而對巖爆的發(fā)生機(jī)制的不穩(wěn)定的特點進(jìn)行了研究，由于斷層高度較低，由煤層頂板和地板的角度來看，就斷層破碎帶和煤力學(xué)性質(zhì)有關(guān)文件，研究巖爆通過綜放采煤工作面相關(guān)的相關(guān)。充當(dāng)研究對象的第14310號NF6故障在東灘煤礦的采煤工作面?zhèn)鬟f。相關(guān)的數(shù)學(xué)模型，用于研究區(qū)域圍巖活動誘發(fā)的巖爆機(jī)制。通過對采煤工作面的微震事故進(jìn)行探討，可以引導(dǎo)巖爆預(yù)測和預(yù)防。 2 工作面采煤時微震活動的監(jiān)測和故障區(qū)域的變化規(guī)律 2.1微震震源變化規(guī)律 波蘭SOS微震監(jiān)測系統(tǒng)在東灘礦進(jìn)行對采煤工作面通過No.NF6時記錄的微震震源位置、能量的變化和微震活動的實時監(jiān)測。對微震震源分布集中和爆力有關(guān)的監(jiān)測結(jié)果進(jìn)行了分析。 如圖1，各點顯示微震震源位置，不同形狀的具有不同微震成績，短黑線表明開挖工作面的位置。根據(jù)監(jiān)測結(jié)果，微震震源改變沿開挖進(jìn)度。在垂直剖面，震源發(fā)生了明顯變化。當(dāng)工作面從斷層遠(yuǎn)，開挖斷層活動的影響不大，微震震源主要分布在前面的采煤工作面和采空區(qū)。 2010年7月26日，采煤工作面故障的距離是在62米，增強(qiáng)附近采煤工作面礦山壓力出現(xiàn)，微震發(fā)生的時間明顯增加，但微震等級小。在這個時候，的微震開始出現(xiàn)斷層附近，這表明斷層活動是由采煤工作面開挖的影響（參見圖1a）。 隨著采煤工作面開挖，微震活動是越來越明顯，震源集中點以上的主要斷層附近的屋頂和堅硬的巖石縫（見圖1C和D）。在2010年8月25日，采煤工作面故障是80米的距離，發(fā)生微震沒有故障的影響，減少微震倍的，微震位置仍然在前面和采煤工作面采空區(qū)開始分發(fā)。據(jù)微震監(jiān)測結(jié)果，預(yù)測和防治有斷層附近地區(qū)開挖擾動下巖爆的危險。 2.2變化的微震總能量和微震倍 根據(jù)開挖進(jìn)度，微震的總能量和微震時代的變化繪制成圖2。在采煤工作面，通過故障期間。 自7月25日，采煤工作面的距離遠(yuǎn)從故障是在60米以上時，微震次數(shù)明顯增加。但微震的總能量變化不大，微震等級，主要是小。之后，8月5、6日，高能量微震開始出現(xiàn)，能源劇烈變化，這提出了兩個原則：首先，微震能量一個特殊的水平上波動，但之間的最大能量和最小能量的幅度差異大。其次，強(qiáng)烈的沖擊發(fā)生之前，微震活動的頻率和檔次有下降的趨勢。強(qiáng)震發(fā)生后，微震通常轉(zhuǎn)向低能量沖擊。因此，低能量沖擊能量積聚的傾向強(qiáng)烈的震撼事故.8月24日之后，微震能量的變化并沒有斷裂構(gòu)造的影響。 3 緊急開挖的影響下斷層附近的礦壓 3.1數(shù)值模擬模型 開采深度為600米以上，均勻分布載荷作用于模型上邊界12.86兆帕（朱等，2007）。 X直接位移模型左邊和右邊是0，X直接位移和Y位移模型底部為0（見圖3）。材料本構(gòu)關(guān)系的Mohr-Coulomb。巖層屬性（見表1），簡稱49號14310號在東灘煤礦的采煤工作面地質(zhì)鉆孔。被稱為故障力學(xué)性能的有關(guān)文件（周等，2006。王等，2003;李等人，2008A，B，C）。 3.2支承壓力故障影響 采煤工作面從故障低墻開挖到故障上墻，當(dāng)采煤工作面和故障之間的不同距離分別為80米，65米，40米，20米，5m 30， 70米， 100米，不同壩肩應(yīng)力分布如圖4所示。表2列出了不同支承應(yīng)力峰值。 面對采煤工作面和故障之間的距離是80米和65米，兩個支承壓力曲線煤提前基本上重合，所以故障支承壓力的影響是非常小的。數(shù)值模擬結(jié)果表明，在采煤工作面煤體應(yīng)力峰值達(dá)到53.37兆帕，應(yīng)力集中系數(shù)達(dá)到3.42，距離遠(yuǎn)采煤工作面煤壁的應(yīng)力峰值為24.2米，應(yīng)力的影響范圍是50米以上。原位觀察結(jié)果表明，應(yīng)力峰值的距離，遠(yuǎn)離面對煤煤壁開挖煤炭高度超過2-3.5倍，應(yīng)力影響范圍為40-60米，應(yīng)力集中系數(shù)為2.5-3。上述兩項研究結(jié)果相似，這解釋了數(shù)值模擬模型是合理的。 隨著采煤工作面接近故障，增強(qiáng)對基牙應(yīng)力故障的影響，應(yīng)力峰值逐漸增加。當(dāng)采煤工作面和故障之間的距離是40米，應(yīng)力峰值達(dá)到70.84兆帕，應(yīng)力集中系數(shù)達(dá)到4.54，距離遠(yuǎn)采煤工作面煤壁的應(yīng)力峰值為25.2中號。當(dāng)采煤工作面和故障之間的距離為20米，應(yīng)力峰值迅速達(dá)到90.21兆帕，應(yīng)力集中系數(shù)達(dá)到5.78，距離遠(yuǎn)采煤工作面煤壁的應(yīng)力峰值為20.12中號。采煤工作面左故障后，在煤體的應(yīng)力逐漸下降，例如，采煤工作面左故障的距離是30米，應(yīng)力峰值下降至74.81兆帕，當(dāng)距離為50米，最高值是52.03兆帕，這是正常開挖。 圖5所示支承壓力分布云圖時有采煤工作面和故障之間的不同距離。當(dāng)采煤工作面的距離接近故障是15米，有明顯的應(yīng)力集中（見圖5a）的斷層附近。當(dāng)采煤工作面左故障的距離是20米（圖5c），斷層附近的巖石縫大多被毀，所以壓力不大。 4 結(jié)論 （1）當(dāng)與深部開采和大開挖高度的綜放工作面通過故障發(fā)生幾個強(qiáng)烈沖擊，這表明，破碎的巖石和煤層范圍和支承應(yīng)力作用下破壞和斷裂構(gòu)造應(yīng)力有斷層附近地區(qū)的巖石爆裂的危險。 （2）微震活動明顯排除。當(dāng)采煤工作面正常出土，微震能量波動在一個特殊的水平。在特殊條件下，強(qiáng)烈的沖擊發(fā)生之前，微震活動的頻率和檔次有下降的趨勢。強(qiáng)震發(fā)生后，微震通常轉(zhuǎn)向低能量沖擊。因此，低能量沖擊，表現(xiàn)出強(qiáng)烈的沖擊發(fā)生的能量積累的趨勢。 （3）當(dāng)工作面接近斷層，煤炭戰(zhàn)線上的支承面對壓力明顯增加，所以附近的斷層巖爆危險更大。 （4）采煤工作面開挖的影響下，事故的不穩(wěn)定性和滑移的可能性，這是因為在事故區(qū)域，微震強(qiáng)度明顯增加，大多由煤層頂板的微震引起。這些規(guī)則可以用來預(yù)測巖爆的危險。 圖1隨著煤炭在垂直剖面斷面開挖微震震源分布的變化 （a）總能量微震的變化（b）微震倍的變化 圖2在的微震能源和采煤工作面通過故障時間直方圖的變化 圖3 數(shù)值模擬模型 表1模型的巖層性質(zhì) 表2支承壓力峰值 圖4 支承壓力分布 圖5 支承壓力分布云圖與采煤工作面和故障之間的不同距離