保護層開采過程中卸載煤體損傷及滲透性演化特征研究
發(fā)布時間：2018-08-30 07:33
【摘要】：保護層開采及卸壓瓦斯抽采是目前首選的區(qū)域性瓦斯治理措施。雖然近年來對保護層開采理論的研究取得了很大突破，然而理論研究還存在不足，目前的研究成果多偏重于宏觀的現象與規(guī)律。本文運用巖石力學、卸荷巖體力學、損傷力學、滲流力學等理論，采用理論研究、實驗室實驗、數值模擬與工程實踐相結合的方法，深入研究了保護層開采過程中被保護層卸載煤體的細觀損傷與滲透性演化特征及被保護層滲透率的分布特征，最后，將研究成果應用于淮南礦區(qū)潘一礦被保護層瓦斯抽采鉆孔的優(yōu)化。本論文的主要研究結論如下： （1）依據被保護層煤體先經歷加載而后三向應力同時被卸載的受力過程，選擇固定軸向位移卸圍壓、固定差應力卸圍壓作為實驗室研究的力學路徑，采用離散性小且力學性質與原煤樣相近的型煤試樣，應用有效應力原理和等效力學路徑的方法通過耦合CT實時檢測實驗與滲透性實驗的結果分析了卸載過程中煤體損傷對滲透性的影響，同一卸載力學路徑下兩不同實驗獲得的應力-應變曲線特征的一致性驗證了把CT實時檢測實驗與滲透性實驗的結果耦合起來分析試樣損傷對滲透性的影響的合理性。 （2）CT檢測實驗結果表明，卸載初期損傷發(fā)育緩慢，隨著損傷的累積，在本論文的實驗條件下，從圍壓卸載至5MPa開始，損傷增長速度加快；試樣最終破壞時內部裂紋呈錐形，且試樣首先從低密度端發(fā)生破壞，進而向高密度端發(fā)展；同一試樣，密度越小的層位，損傷發(fā)展越快，同時，固定差應力卸圍壓應力路徑對試樣造成的損傷更大。 （3）卸載過程中滲透性實驗結果表明，隨著初始圍壓的增大，固定軸向位移卸圍壓與固定差應力兩種卸載力學路徑下，差應力減小速率增大處的圍壓值升高；卸載力學路徑下，卸載點前加載階段，滲透率與軸向應變的關系為k A B11e（A1、B1為擬合系數）；卸載點后卸載階段，滲透率與軸向應變的關系為k AB2e2（A2、B2為擬合系數）。 （4）推導出了用根據CT值表示的損傷變量，獲得了卸載過程中損傷變量的變化，結合等效力學路徑下滲透性實驗的結果，獲得了卸載煤體損傷對滲透性的影響，即卸載初期損傷與滲透率增加均較小，隨著繼續(xù)卸載，，在本論文的實驗條件下，兩種卸載路徑下有效圍壓均卸載至5MPa左右后，損傷和滲透率的增加速度均加快。 （5）依據被保護層的膨脹變形情況與實驗室獲得的滲透率與軸向應變的關系，利用Matlab軟件的Surf函數得出了被保護層滲透率的分布特征，即被保護層可分為原始滲透性區(qū)、滲透性減小區(qū)、滲透性增大區(qū)1、滲透性增大區(qū)2，基于此，從被保護層切眼和收作線附近區(qū)域至工作面內部，瓦斯抽采鉆孔的布孔間距依次設計為5m×5m，10m×10m，40m×40m，被保護層工作面掘進、回采期間的瓦斯參數驗證了瓦斯抽采鉆孔布孔方式優(yōu)化的合理性。
[Abstract]:Protection layer mining and pressure relief gas drainage is the first choice of regional gas control measures. Although great breakthrough has been made in the research of the mining theory of protective layer in recent years, there are still some deficiencies in the theoretical research, and the current research results are mostly focused on the macroscopic phenomena and laws. In this paper, the theories of rock mechanics, unloading rock mass mechanics, damage mechanics, seepage mechanics and so on are used, and the methods of combining theoretical research, laboratory experiments, numerical simulation and engineering practice are adopted. The evolution characteristics of meso-damage and permeability and the distribution characteristics of permeability of protected layer are studied in detail. The research results are applied to the optimization of gas drainage boreholes in Panyi Mine, Huainan Mining area. The main conclusions of this paper are as follows: (1) according to the loading and unloading process of the coal body in the protected layer, the fixed axial displacement unloading pressure is selected. Fixed differential stress unloading confining pressure is used as the mechanical path of laboratory research. Briquette samples with small dispersion and similar mechanical properties to raw coal samples are used. The effect of coal damage on permeability during unloading is analyzed by using effective stress principle and equivalent mechanical path method through coupled CT real-time detection experiment and permeability experiment. The consistency of stress-strain curves obtained from two different experiments under the same unloading mechanics path verifies the rationality of coupling the results of CT real-time detection experiment and permeability experiment to analyze the effect of specimen damage on permeability. (2) the results of CT test showed that, At the initial stage of unloading, the damage develops slowly, and with the accumulation of damage, the damage growth rate is accelerated from confining pressure to 5MPa under the experimental conditions in this paper, and the internal crack is conical when the specimen is finally destroyed. At the same time, the smaller the density of the sample, the faster the damage development, and at the same time, The damage caused by the confining stress path of fixed differential stress unloading is greater. (3) the experimental results of permeability during unloading show that with the increase of initial confining pressure, Under the two unloading mechanical paths of fixed axial displacement unloading pressure and fixed differential stress, the confining pressure increases at the increase of the decreasing rate of the differential stress, and under the unloading mechanics path, the loading stage of the unloading point before loading, The relationship between permeability and axial strain is k A B 11e (A 1B 1 is the fitting coefficient), the relation between permeability and axial strain is k AB2e2 (A 2 B 2 is fitting coefficient). (4) after unloading point, and the damage variable expressed according to CT value is derived. The change of damage variables during unloading is obtained. Combined with the experimental results of permeability under equivalent mechanical path, the influence of unloading coal damage on permeability is obtained, that is, the damage and permeability increase in the initial stage of unloading are small, and with the further unloading, Under the experimental conditions in this thesis, the effective confining pressures under two unloading paths are unloaded to 5MPa or so. Both damage and permeability increase faster. (5) according to the relationship between the expansion deformation of the protected layer and the permeability obtained in the laboratory and axial strain, the distribution characteristics of the permeability of the protected layer are obtained by using the Surf function of Matlab software. That is, the protected layer can be divided into the original permeability area, the permeability decreasing area, the permeability increasing area 1, the permeability increasing area 2. Based on this, from the area near the protected layer cutting and closing line to the working face, The spacing of the gas drainage boreholes is designed as 5 m 脳 5 m 10 m 40 m 脳 40 m, and the gas parameters during the mining process verify the rationality of the optimization of the distribution mode of the gas drainage boreholes.
【學位授予單位】：中國礦業(yè)大學
【學位級別】：博士
【學位授予年份】：2013
【分類號】：TD712
本文編號：2212366
[Abstract]:Protection layer mining and pressure relief gas drainage is the first choice of regional gas control measures. Although great breakthrough has been made in the research of the mining theory of protective layer in recent years, there are still some deficiencies in the theoretical research, and the current research results are mostly focused on the macroscopic phenomena and laws. In this paper, the theories of rock mechanics, unloading rock mass mechanics, damage mechanics, seepage mechanics and so on are used, and the methods of combining theoretical research, laboratory experiments, numerical simulation and engineering practice are adopted. The evolution characteristics of meso-damage and permeability and the distribution characteristics of permeability of protected layer are studied in detail. The research results are applied to the optimization of gas drainage boreholes in Panyi Mine, Huainan Mining area. The main conclusions of this paper are as follows: (1) according to the loading and unloading process of the coal body in the protected layer, the fixed axial displacement unloading pressure is selected. Fixed differential stress unloading confining pressure is used as the mechanical path of laboratory research. Briquette samples with small dispersion and similar mechanical properties to raw coal samples are used. The effect of coal damage on permeability during unloading is analyzed by using effective stress principle and equivalent mechanical path method through coupled CT real-time detection experiment and permeability experiment. The consistency of stress-strain curves obtained from two different experiments under the same unloading mechanics path verifies the rationality of coupling the results of CT real-time detection experiment and permeability experiment to analyze the effect of specimen damage on permeability. (2) the results of CT test showed that, At the initial stage of unloading, the damage develops slowly, and with the accumulation of damage, the damage growth rate is accelerated from confining pressure to 5MPa under the experimental conditions in this paper, and the internal crack is conical when the specimen is finally destroyed. At the same time, the smaller the density of the sample, the faster the damage development, and at the same time, The damage caused by the confining stress path of fixed differential stress unloading is greater. (3) the experimental results of permeability during unloading show that with the increase of initial confining pressure, Under the two unloading mechanical paths of fixed axial displacement unloading pressure and fixed differential stress, the confining pressure increases at the increase of the decreasing rate of the differential stress, and under the unloading mechanics path, the loading stage of the unloading point before loading, The relationship between permeability and axial strain is k A B 11e (A 1B 1 is the fitting coefficient), the relation between permeability and axial strain is k AB2e2 (A 2 B 2 is fitting coefficient). (4) after unloading point, and the damage variable expressed according to CT value is derived. The change of damage variables during unloading is obtained. Combined with the experimental results of permeability under equivalent mechanical path, the influence of unloading coal damage on permeability is obtained, that is, the damage and permeability increase in the initial stage of unloading are small, and with the further unloading, Under the experimental conditions in this thesis, the effective confining pressures under two unloading paths are unloaded to 5MPa or so. Both damage and permeability increase faster. (5) according to the relationship between the expansion deformation of the protected layer and the permeability obtained in the laboratory and axial strain, the distribution characteristics of the permeability of the protected layer are obtained by using the Surf function of Matlab software. That is, the protected layer can be divided into the original permeability area, the permeability decreasing area, the permeability increasing area 1, the permeability increasing area 2. Based on this, from the area near the protected layer cutting and closing line to the working face, The spacing of the gas drainage boreholes is designed as 5 m 脳 5 m 10 m 40 m 脳 40 m, and the gas parameters during the mining process verify the rationality of the optimization of the distribution mode of the gas drainage boreholes.
【學位授予單位】：中國礦業(yè)大學
【學位級別】：博士
【學位授予年份】：2013
【分類號】：TD712
【參考文獻】
相關期刊論文 前10條
1 任建喜,羅英,劉文剛,李新虎;CT檢測技術在巖石加卸載破壞機理研究中的應用[J];冰川凍土;2002年05期
2 劉小紅;晏鄂川;朱杰兵;汪斌;;三軸加卸載條件下巖石損傷破壞機理CT試驗分析[J];長江科學院院報;2010年12期
3 程展林;左永振;丁紅順;;CT技術在巖土試驗中的應用研究[J];長江科學院院報;2011年03期
4 楊天鴻,徐濤,馮啟言,唐春安;脆性巖石破裂過程滲透性演化試驗[J];東北大學學報;2003年10期
5 唐春安,黃明利,張國民,焦明若;巖石介質中多裂紋擴展相互作用及其貫通機制的數值模擬[J];地震;2001年02期
6 黃潤秋;黃達;;卸荷條件下巖石變形特征及本構模型研究[J];地球科學進展;2008年05期
7 尤明慶;巖樣三軸壓縮的破壞形式和Coulomb強度準則[J];地質力學學報;2002年02期
8 毛靈濤;安里千;王志剛;石鵬;商雅楠;;煤樣力學特性與內部裂隙演化關系CT實驗研究[J];遼寧工程技術大學學報(自然科學版);2010年03期
9 劉向峰;汪有剛;;聲發(fā)射能量累積與煤巖損傷演化關系初探[J];遼寧工程技術大學學報(自然科學版);2011年01期
10 吳剛;工程巖體卸荷破壞機制研究的現狀及展望[J];工程地質學報;2001年02期
相關博士學位論文 前5條
1 劉豆豆;高地應力下巖石卸載破壞機理及其應用研究[D];山東大學;2008年
2 王海鋒;采場下伏煤巖體卸壓作用原理及在被保護層卸壓瓦斯抽采中的應用[D];中國礦業(yè)大學;2008年
3 王亮;巨厚火成巖下遠程卸壓煤巖體裂隙演化與滲流特征及在瓦斯抽采中的應用[D];中國礦業(yè)大學;2009年
4 高保彬;采動煤巖裂隙演化及其透氣性能試驗研究[D];北京交通大學;2010年
5 劉洪永;遠程采動煤巖體變形與卸壓瓦斯流動氣固耦合動力學模型及其應用研究[D];中國礦業(yè)大學;2010年
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