本文關鍵詞：淺埋薄基巖采煤工作面覆巖縱向貫通裂隙演化規(guī)律研究　出處：《中國礦業(yè)大學(北京)》2016年博士論文　論文類型：學位論文

  更多相關文章： 淺埋 薄基巖 縱向貫通裂隙 裂隙張開 裂隙閉合

【摘要】：我國西部地區(qū)蘊藏著十分豐富的煤炭資源,神東煤田是中國已探明的最大煤田,位于內蒙古自治區(qū)南部地區(qū)與陜西省西北部地區(qū),煤田總面積達22860km2。該區(qū)域的煤炭資源為我國的國民經濟發(fā)展做出了突出貢獻,由于煤層賦存條件簡單且厚度大等優(yōu)勢,為煤炭的機械化、高強度開采提供了得天獨厚的條件,但在實際的開采中又由于煤層的埋深淺、基巖薄、上覆松散層厚度大,使得工作面在回采過程中上覆巖層產生的裂隙形成了溝通工作面與上覆松散層的裂隙,裂隙甚至能直達地表,若覆松散層富含潛水就會造成潰水潰砂災害,對礦井的安全生產造成了極大的隱患。所以掌握神東礦區(qū)這種淺埋深、基巖薄的條件下產生的縱向裂隙演化規(guī)律,并采取相應的對策預防潰水潰砂災害的發(fā)生對神東礦區(qū)礦井的安全高效綠色開采將具有重要意義。本文以昌漢溝礦為工程背景,掌握了開采煤層覆巖特征、煤巖物理力學性質、含煤巖系巖石學特征和原始沉積環(huán)境覆巖穩(wěn)定性,通過相似模擬和數值模擬手段分析了淺埋薄基巖工作面縱向貫通裂隙演變規(guī)律,建立了上覆巖層力學模型,掌握了工作面縱向貫通裂隙的演化過程,并通過對縱向貫通裂隙的現場實測研究,最終提出了潰水潰砂的控制技術。本文主要結論如下:(1)掌握了昌漢溝礦4煤組覆巖結構特征與穩(wěn)定性昌漢溝礦區(qū)4煤組沉積環(huán)境主要為河流中下游泛濫平原沉積環(huán)境;從昌漢溝礦圍巖顯微組分可以觀測出,昌漢溝礦砂巖膠結類型為泥質膠結,固結成巖作用弱,導致巖石強度較低,同時由于粘土成分含量高,遇水會出現膨脹和崩解,會成分頂板穩(wěn)定性帶來不良影響;依據研究區(qū)內成煤環(huán)境內砂泥比不同取值范圍,劃分出Ⅰ~Ⅴ級五類沉積相巖層穩(wěn)定性分區(qū)。昌漢溝礦4煤組煤Ⅰ~Ⅴ級分區(qū)均有分布,且以Ⅲ~Ⅴ級分區(qū)為主;計算出不同分區(qū)的沉積相巖層穩(wěn)定性影響因素,Ⅰ級取1.00、Ⅱ級0.83、Ⅲ級0.65、Ⅳ級取0.60和Ⅴ級取0.58。此沉積相巖層穩(wěn)定性系數可用于頂板巖層穩(wěn)定性分類計算中,量化了各區(qū)原始沉積環(huán)境差異。(2)揭示了淺埋薄基巖工作面縱向貫通裂隙演變規(guī)律采用相似模擬分析,獲取了工作面的縱向貫通裂隙演化過程初步得到裂隙的演化的四個階段,分別為:(1)裂隙孕育階段:在此階段過程中,基本頂發(fā)生初次垮落,隨著工作面繼續(xù)向前開采,前方的一定區(qū)域內開始出現縱向裂隙,而且隨著開采的進行,裂隙呈現逐漸擴展的狀態(tài),擴展的最終結果貫通工作面與載荷層,在此期間,開始出現第一次周期來壓。(2)裂隙張開階段:當發(fā)生第一次周期來壓時,上覆基巖發(fā)生回轉,回轉過程以縱向貫通裂隙為軸線,向采空區(qū)方向回轉,上覆基巖的回轉使得本已存在的縱向裂隙逐漸張開,當覆巖回轉至極限時,裂隙不再繼續(xù)張大。(3)裂隙迅速閉合階段:當工作面采高較大時,隨著工作面的繼續(xù)推進,第一次周期來壓所形成的巖塊在支架后方發(fā)生整體切落,覆巖反向回轉,巖塊垮落后的產生碎脹,而且跨落后裂隙結構面不平整,導致縱向貫通裂隙迅速閉合。(4)裂隙壓實階段:當第二次周期來壓時,相鄰覆巖發(fā)生回轉運動,對已垮落巖塊產生擠壓作用力,使得已經閉合縱向貫通裂隙被進一步壓實。采用數值模擬的方法進行淺埋薄基巖工作面上覆巖層的縱向貫通裂隙張開、閉合過程研究,進一步細致分析了采動影響下工作面縱向貫通裂隙動態(tài)發(fā)育現象,即張開閉合現象:基本頂在工作面推進過程中所形成的結構狀態(tài)及其破斷失穩(wěn)決定了工作面縱向貫通裂隙的發(fā)育擴展過程。周期來壓過程中,由于基本頂巖塊的回轉造成覆巖縱向裂隙尺寸不斷增大,隨著破斷覆巖的整體切落與反向回轉,出現縱向貫通裂隙的分離單元體之間又開始重新接觸,由此可知縱向貫通裂隙已經閉合;當第二次周期來壓時,相鄰覆巖發(fā)生回轉運動,對已垮落巖塊產生擠壓作用力,使得已經閉合縱向貫通裂隙被進一步壓實。通過數值計算,工作面縱向貫通裂隙的整個動態(tài)發(fā)育狀態(tài)與相似模擬結果基本相同。(3)從力學機制上闡述了工作面潰砂潰水原因針對神東煤炭集團昌漢溝煤礦這一典型淺埋薄基巖采煤工作面進行了縱向貫通裂隙演化過程力學分析,在淺埋薄基巖的條件下,由于工作面持續(xù)推進,靠后的周期來壓會使前一次周期來壓產生的關鍵巖塊出現切落現象,此時關鍵巖塊的前段角在受到向下的剪切力和水平力的共同作用,會形成近似的“臺階巖梁”結構,從而建立了淺埋博基巖采煤工作面縱向貫通裂隙演化過程的力學模型。由于工作面的持續(xù)推進造成頂板關鍵巖塊的周期性破斷,從而產生了淺埋薄基巖的頂板縱向貫通裂隙,其裂隙尺寸受實際地質條件影響巨大,與破斷巖塊間的塊度、相互間的錯位量和其所受的水平力大小、工作面采高、直接頂厚度等密切相關,當裂隙由于關鍵巖塊的回轉而擴展到一定的程度時,就會使主導周期來壓產生的關鍵巖塊發(fā)生切落,并使得上一周期來壓產生的縱向貫通裂隙發(fā)生閉合,隨后這次周期來壓產生的縱向貫通裂隙經歷張開擴展后又會由于下一個周期來壓產生的縱向貫通裂隙而閉合,周而復始。(4)提出了工作面潰砂潰水的控制方法①合理安排工作面推進速度工作面的推進速度對覆巖移動特征和裂隙發(fā)育程度影響較明顯。工作面推進速度越快相應的覆巖的下沉量越是平緩,所以其整體性就越強,相應的導水裂隙發(fā)育程度越小,對潰水潰砂的防治起一定的促進作用。一方面,快速推進的工作面使動態(tài)變形過程相應縮短,上覆巖層越近整體連續(xù)變形的壓實效果越好。另一方面,工作面的快速推進使破斷巖塊間的裂隙發(fā)育時間短并且快速發(fā)生結構性閉合,從而阻止了導水通道的形成,也阻止了潰水潰砂的發(fā)生。破斷巖塊回轉角的大小一般受基本頂周期來壓步距的長短直接控制,即周期來壓步距越小就會使回轉角就越大,導致工作面縱向貫通裂隙發(fā)育程度也越高。一般情況下淺埋薄基巖工作面周期來壓步距相對較小,縱向貫通裂隙不貫通的情況基本不存在,工作面推進速度一定得控制好。周期來壓來臨前,采用注漿等手段“堵”住縱向貫通裂隙,避免水砂通道的形成;來壓之后,縱向貫通裂隙即刻開始發(fā)生結構性閉合,可不做處理。所以,工作面推進速度一定得控制好,尤其是在基巖周期來壓來前,適當加快推進,避免間歇性停頓,以減小潰砂潰水事故隱患。②增大液壓支架支撐力現場工作中要減小基巖切落前巖塊的回轉角度就必須保證液壓支架工作阻力和作用面積,這樣就會使得縱向貫通裂隙在產生小的尺寸后直接被快速切落,縱向貫通裂隙迅速閉合。同時,在裂隙閉合階段進行再進行工作面暫停推進的檢修、注漿等工序以便將安全隱患降到最低。此外,從工作面頂板和支架頂梁的幾何關系看,應注重支架頂梁支撐力的發(fā)揮,加強支架頂梁的支撐力,弱化支架掩護梁的作用。盡量減小頂板暴露時間和面積,弱化薄基巖的頂板承載能力低的缺點。③富水區(qū)域限厚開采基巖破斷塊體的回轉變形空間主要受采空區(qū)的充填程度影響,較大的懫空空間使得采空區(qū)充填程度較低,直接導致破斷巖塊回轉角變大,進而,加大了工作面縱向貫通裂隙發(fā)育程度。因此,富水區(qū)域可適當降低采高,增加直接頂厚度相應的直接增加采后矸石在采空區(qū)的充填程度,以降低破斷巖塊回轉角,限厚開采的同時也加快了工作面推進速度,有利于覆巖縱向貫通裂隙的快速閉合,減小潰砂潰水事故隱患。(5)形成了工作面潰水潰砂控制方法,并進行了工程實踐對于淺埋薄基巖煤層而言,隨著煤層的開采,其上覆巖層裂隙導通松散含水松散層,上部水體便會沿導水裂隙滲流。可靠的初撐阻力,保證工作面在斷裂巖塊下不至于產生較大的貫通裂縫;而推進速度的加快,可使破斷巖塊盡快與工作面一側未斷巖層在斷面下端鉸接并擠壓發(fā)生結構性閉合,并在上覆垂直載荷作用下得到壓實,從而有效控制了巖層的裂隙率、滲透性、導水性。據此在開采昌漢溝礦201工作面時,對工作不同區(qū)域的周期來壓位置、來壓位置附近是否出現潰砂潰水事故或潰水潰砂跡象進行了統(tǒng)計,統(tǒng)計結果表明,采用以合理安排工作面推進速度、增大液壓支架支撐力為主的潰砂潰水綜合防治方法,工作面推進期間,未出現潰水潰砂隱患,實現了礦井的安全、高效開采。
[Abstract]:The western region of China is rich in coal resources, Shendong coalfield is the largest coal Chinese proven, northwest of the southern region is located in the the Inner Mongolia Autonomous Region coalfield and Shaanxi Province, a total area of 22860km2. in the area of coal resources for the development of China's national economy has made outstanding contributions, the occurrence condition of coal seam thickness and simple the big advantages, for the mechanization of coal mining, high strength provides richly endowed by nature, but in the actual mining because the coal seam buried depth, thin bedrock and overlying loose layer thickness is large, the work surface strata in the mining process of the cracks formed communication working surface and the overlying loose layer crack, crack can even reach the ground, if the overburden layer is rich in water and sand burst diving will cause disaster to the safety production of mine caused great hidden danger. So the god east this area A shallow buried depth, longitudinal cracks and thin bedrock under the condition of evolution, and take corresponding measures to prevent collapse of water and sand disaster safe and efficient green mining of mine in Shendong mining area will have important significance. In this paper, Chang Han Gou mine as the engineering background, the characteristics of coal mining overburden rock physical mechanics. Coal properties, coal bearing strata and petrological characteristics of original sedimentary environment of overlying rock stability, through the simulation and numerical simulation analysis of the shallow buried thin bedrock surface longitudinal through cracks evolution, established overburden mechanics model, the evolution process of the master working face longitudinal through cracks, and through the field test research the longitudinal through cracks, finally put forward the control technology of water and sand burst. The main conclusions of this paper are as follows: (1) Master Chang Han Gou coal mine 4 group overburden structure characteristics and stability of Chang Han Gou mine 4 Coal Group The sedimentary environment is mainly in the middle and lower reaches of the river flood plain sedimentary environment; from Chang Han Gou rock macerals can be observed, Chang Han Gou mine sandstone cementation type is clay cementation, consolidation of weak diagenesis, the rock strength is low, and because the clay content is high, water will swell and collapse. It has negative effects on roof stability of components in the study area; on the basis of coal forming environment in different sand shale ratio range, Division I ~ V grade five types of sedimentary rock facies stability zoning. Chang Han Gou coal mine 4 Coal Group I ~ V grade partition were distributed, and III ~ V grade partition; calculate rock facies factors in different areas of stability, grade 1, grade 0.83, grade 0.65, grade 0.60 and grade V 0.58. of this sedimentary facies strata stability coefficient can be used for classification of roof strata stability calculation, quantitative appraisethe original sedimentary environment Difference. (2) revealed a shallow buried thin bedrock working surface longitudinal through cracks evolution with simulation analysis, four stages of working face were obtained through the longitudinal crack evolution process of the fracture evolution obtained were: (1) crack incubation stage: in this stage in the process of the basic roof first caving occurred with the face, to continue mining, began to appear a certain area in front of the longitudinal cracks, and with the exploitation of the fissure, gradually expanded state of the final results through the extended working surface and the load layer, in the meantime, begin the first periodic press. (2) fracture occurs when the first stage: the cycle pressure when the overlying bedrock occurs in the longitudinal rotary rotary process through cracks for the axis, to the goaf overlying bedrock of the direction of rotation, the rotary vertical cracks of the existing open gradually, when the rock back to The limit, no longer continue to crack big. (3) crack rapid closing stage: when the mining height is large, with the continued progress of working face, the rock first cycle pressure formed in the bracket behind the whole cutting, overburden rock fall reversal, have broken, and cross behind the fissure structural plane is not flat, causing longitudinal through cracks quickly closed. (4) the stage of crack compaction: when the second cycle pressure when the overburden occurs adjacent rotary motion, squeezing force to have caving rock, which has been closed through the longitudinal fissure. Further compaction of overlying strata in using numerical simulation method the shallow buried thin bedrock face vertical fracture, closed process research, further detailed analysis of the working face under the influence of vertical dynamic development of mining fissure phenomenon, namely open close phenomenon: the basic roof in the working face advancing Structure formed in the process of breaking and instability determines the working face through vertical fissure propagation process. The periodic weighting process, because the basic roof rock strata caused by rotary vertical fissure size increasing, with the overall breaking rock cut down and reverse turn, between the separation unit longitudinal through cracks began to contact the longitudinal through cracks have been closed; when the second cycle pressure when the overburden occurs adjacent rotary motion, squeezing force to have caving rock, which has been closed through further longitudinal cracks are compacted. Through numerical calculation, the dynamic development of working face the longitudinal through cracks and similar simulation results are basically the same. (3) from the mechanical mechanism described the working face water inrush of sand break reason for Shendong Coal Group Chang Han Gou coal mine is a typical shallow thin base Rock coal face are analyzed through vertical crack evolution mechanics in shallow buried thin bedrock under the condition, because of the continued advance of working face, the key rock block cycle by the pressure to make a periodic pressure resulting from the emergence of the cut phenomenon, at this time the key rock block front angle in the interaction by the downward shear force and horizontal force, will form an approximate "step beam" structure, which established the mechanical model of shallow bedrock mining work Bo longitudinal through cracks evolution. Due to the continued advance caused by periodic roof breaking key rock block, resulting in the roof of shallow thin bedrock the longitudinal through cracks, the crack size is affected by the actual geological condition is huge, and broken rock blocks between the block, offset each other and the horizontal force of the size of the mining height, the thickness of immediate roof closely related, when crack The key block of rotary gap and extended to a certain extent, it will make the key rock leading periodical pressure generated block cutting, and the longitudinal through cracks a closed cycle pressure generated by the vertical fracture experienced open expansion again because of the next cycle pressure generated the longitudinal through cracks and closed cycle, then the cycle pressure generated. (4) put forward the control method of working face water inrush of sand break the reasonable arrangement of the advancing speed of working face advancing speed of overburden movement characteristics and the degree of fracture effect is obvious. To promote the faster the corresponding rock face the subsidence is more gentle, so the greater degree of water flowing fractured development corresponding smaller, certain promotion on the prevention and control of water inrush and sand play a role. On the one hand, the rapid advance of the working face of the dynamic deformation process Shortened, the better compaction effect of overlying strata is nearly the whole continuous deformation. On the other hand, the rapid advance of the broken rock between the fractured time and rapid structural closure, thereby preventing the formation of water channel, also prevents the collapse of water and sand the occurrence of broken rock. Back to the angle of the general basic roof periodic weighting step length of direct control, namely the periodic weighting step distance will make more small rotation angle is greater, resulting in working face through the longitudinal crack growth degree is higher. The thin bedrock shallow generally face periodic weighting is relatively small the longitudinal through cracks not through the basic does not exist, the speed of working face must have good control. The cycle pressure before, by means of grouting blocking live through vertical fissures, avoid the formation of water channel sand; pressure, vertical fracture Immediately start a structural closure, can not do. So, the speed of working face must have good control, especially in the bedrock cycle pressure, appropriate to accelerate, avoid intermittent pauses, to reduce the inrush of sand water inrush accidents. The increase of supporting force of hydraulic support field work to reduce rock cutting the rotation angle before the rock must be ensured and the support function of hydraulic resistance area, this causes the longitudinal through cracks in small size directly after fast cutting, longitudinal through cracks quickly closed. At the same time, in the stage of crack closure and suspension working face advance grouting process for maintenance, security risks to a minimum. In addition, the geometric relationship between the roof and the support beam, should to pay great attention to the support support force, strengthen the supporting force of support beam, weakening the shield for Use. To reduce the exposure time and area of the roof, roof weakening thin bedrock bearing capacity low. The water rich area mining thick limit bedrock breaking block rotary deformation space is mainly affected by the degree of filling the goaf, the larger Zhi empty space makes the goaf filling degree is relatively low, directly lead to broken broken rock rotating angle becomes larger, thus, increase the working face through vertical fissures. Therefore, water rich area may be appropriate to reduce the mining height, increase the thickness of immediate roof corresponding directly increase postharvest gangue filling degree of goaf, in order to reduce the broken rock turning, mining thick limit at the same time also accelerate the speed of working face, there is conducive to rapid closure of overburden longitudinal through cracks, reduce the inrush of sand water bursting accidents. (5) the formation of working face water inrush and sand control method, and the engineering practice for shallow buried thin bedrock coal seam, with the Coal mining, overlying rock fissure conducting loose water bearing alluvium, upper water will be along with the water seepage. Reliable setting resistance, ensure working face in broken rock blocks under not large crack; and to promote the speed of the broken rock and as soon as possible the working side not broken rock in the cross section is hinged with the lower end of structural and squeeze the closed, and compacted in overburden under vertical load, so as to effectively control the rock fracture rate, permeability, water conductivity. The exploitation of Chang Han Gou mine 201 working face, the cycle in different regions to work pressure position whether there is pressure, near the inrush of sand water bursting or collapse of water and sand signs for the statistics, statistical results show that the speed of the reasonable arrangement of work, comprehensive prevention and control of water inrush of sand crushing method to increase hydraulic support force, advancing working face During the period, the hidden danger of sand break and sand break was not appeared, which realized the safety and efficient mining of the mine.

【學位授予單位】：中國礦業(yè)大學(北京)
【學位級別】：博士
【學位授予年份】：2016
【分類號】：TD32

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