本文選題：含瓦斯煤 + 力學屬性�。� 參考：《重慶大學》2014年博士論文

【摘要】：隨著我國煤炭需求量的逐年攀升,煤礦開采不斷地向深部延伸,面對“三高一低”(高地應力、高地溫、高瓦斯壓力和低滲透性)的煤炭資源,瓦斯災害日益嚴重,煤與瓦斯共采技術已成為了開采深部煤炭資源的首選和必然。人工采掘活動,改變了煤體的應力場和溫度場,進而又引起了煤體中的瓦斯運移,因此研究應力和溫度耦合作用下含瓦斯煤的變形特性和滲透特性、含瓦斯煤滲透特性的影響因素及煤層瓦斯抽采過程中的瓦斯?jié)B流規(guī)律都是深部煤炭資源開采的重點和難點。本文以貴州礦區(qū)玉舍煤礦1#煤層為主,兼有其他6個煤層煤樣為研究對象,采用實驗室測定、理論研究、數(shù)值模擬及工程應用相結合的方法,從含瓦斯煤的變形及滲流特性、滲透特性影響因素、煤層瓦斯抽采的物理模擬等角度出發(fā),系統(tǒng)開展了含瓦斯煤的基本物理力學屬性、熱流固耦合作用下煤的變形特性和滲透特性、含瓦斯煤滲透特性影響因素及瓦斯抽采條件下的物理模擬等試驗研究和理論分析,同時進行了煤層瓦斯抽采數(shù)值模擬分析,并結合滲流力學、巖石力學及彈性力學從理論層面上進行了一系列有益的探討。通過本文的研究,在以下方面取得了一些進展:1)分析了含瓦斯煤的內外部孔隙特征,并開展單軸抗壓強度、三軸抗壓強度及變形特性試驗,得到了煤的變質程度與其內外部孔、裂隙發(fā)育程度均呈正相關關系,煤層粒徑、堅固性系數(shù)和其基本力學參數(shù)的關系。對煤的吸附解吸特性進行了試驗研究,得到了不同溫度下的等溫吸附曲線及吸附常數(shù)a、b隨溫度的變化規(guī)律,與煤的內部孔隙特征關系。2)改進了現(xiàn)有偽三軸滲流設備,開展了不同溫度和圍壓條件下含瓦斯煤的三軸壓縮試驗,分析了溫度和圍壓對含瓦斯煤力學參數(shù)的影響。探討了含瓦斯煤破壞前的圍壓、溫度對滲透率及軸向應變的影響規(guī)律,含瓦斯煤在破壞過程中圍壓和溫度與滲透率特征值之間量化關系及隨其變化的趨勢,全面闡述了滲透率滯后效應的作用機理。3)開展了應力、溫度、含水率和粒徑條件下的三軸滲流試驗,分析了熱力多因素耦合作用下含瓦斯煤滲透特性的變化規(guī)律,推導了含水率和溫度、含水率和有效應力耦合作用下含瓦斯煤滲透率關系式,探討了滲透率的影響機理。開展了不同變質程度和不同堅固性系數(shù)含瓦斯煤的三軸滲流試驗,分析了煤的變質程度與其外部孔、裂隙發(fā)育程度關系,煤的堅固性系數(shù)與瓦斯放散初速度、三軸抗壓強度及滲透率關系。4)對三軸滲流設備的出口端增設了正壓調節(jié)閥,開展了出口正壓條件下的孔隙壓力試驗,得到含瓦斯煤滲透率與孔隙壓力關系,分析了孔隙壓力與溫度耦合作用下對含瓦斯煤滲透率的影響規(guī)律。定義了孔隙壓力敏感系數(shù),推導了孔隙壓力敏感系數(shù)與孔隙壓力之間關系,探討孔隙壓力對含瓦斯煤滲透率的響應程度。5)改進了現(xiàn)有的三軸滲流設備,開展出口正壓、出口大氣壓和出口負壓的三軸滲流試驗,分析了不同有效應力、溫度條件下含瓦斯煤的滲流規(guī)律,探討了含瓦斯煤瓦斯流速與熱應力、外荷載作用、孔隙壓力和煤骨架變形及吸附作用之間作用機理。6)開展了出口負壓的三軸滲流試驗,對比分析了三種出口負壓對瓦斯流速的影響,揭示了適當減小出口負壓有利于瓦斯流動的機理。在最佳出口負壓的基礎上,研究了抽采管徑和抽采管路長度對含瓦斯煤瓦斯流速影響,含瓦斯煤瓦斯流速隨管徑的增加而增大,隨溫度的增加而減小及隨管路長度的延長而降低的變化規(guī)律。7)建立了含瓦斯煤系統(tǒng)總應變方程,考慮滑脫效應的滲透率變化模型,并結合氣體流動的連續(xù)性方程、含瓦斯煤變形平衡方程及幾何方程,構建了包含應力場和滲流場并考慮氣體滑脫效應的含瓦斯煤系統(tǒng)流固耦合方程。通過數(shù)值模擬分析和物理模擬試驗對比,驗證了模型的正確性和適用性,對比分析了煤體內氣體壓力沿徑向分布和煤體內氣相滲透率的變化規(guī)律。以貴州玉舍煤礦1#煤層穿層鉆孔為工程計算實例,分析了計算區(qū)域、截面上瓦斯壓力隨抽采時間的變化規(guī)律,對比了計算區(qū)域在相同抽采時刻不同位置的瓦斯壓力變化趨勢,揭示了不同抽采負壓條件下計算模型瓦斯流量的演化規(guī)律,并就不同階段最佳抽采負壓進行了探討。
[Abstract]:With the increasing demand of coal in China, coal mining continues to extend to the deep. In the face of the coal resources of "three high and one low" (high ground stress, high ground temperature, high gas pressure and low permeability), the gas disaster is becoming more and more serious. Coal and Gas Co mining technology has become the first choice and necessity of mining deep coal resources. The stress field and temperature field of coal body are changed, and then the gas migration in coal body is caused. Therefore, the research on the deformation characteristics and permeability characteristics of coal containing gas under the coupling of stress and temperature, the influencing factors of the permeability characteristics of gas coal and the law of gas seepage in the process of coal seam gas extraction are the key points in the mining of deep coal resources. In this paper, based on the 1# coal seam in the Guizhou mining area of Yu she coal mine, and with 6 other coal seam samples as the research object, the method of combining the laboratory testing, theoretical research, numerical simulation and engineering application is used, from the angle of the deformation and seepage characteristics of the coal gas, the influence factors of the permeability, the physical simulation of the coal seam gas extraction, etc. The system has carried out the basic physical and mechanical properties of coal bearing coal, the deformation characteristics and permeability characteristics of the coal, the influence factors of the permeability of coal and the physical simulation under the condition of gas extraction, and the numerical simulation analysis of the coal seam gas extraction. A series of beneficial discussions have been carried out on the theoretical level of mechanics and elasticity. Through this study, some progress has been made in the following aspects: 1) the characteristics of the inner and outer pores of the coal containing gas are analyzed, and the uniaxial compression strength, the three axis compressive strength and the deformation characteristics are tested, and the metamorphism of coal and the holes in the inner and outer parts of the coal are obtained. The relationship between the gap development degree is positive correlation, the coal seam particle size, the strength coefficient and its basic mechanical parameters. The adsorption desorption characteristics of coal are studied. The isothermal adsorption curve and the adsorption constant a at different temperatures, the variation of B with the temperature and the internal pore characteristics of coal.2) have been obtained. The existing pseudo three axis seepage is improved. Three axial compression tests of coal containing gas under different temperature and confining pressure were carried out. The influence of temperature and confining pressure on the mechanical parameters of coal bearing coal was analyzed. The influence of confining pressure on coal bearing coal before failure, the influence of temperature on permeability and axial strain, and the characteristic value of peri pressure, temperature and permeability during the failure process were discussed. The quantitative relationship and the trend of its variation, the mechanism.3 of the permeability lag effect is fully expounded. The three axis seepage tests under the conditions of stress, temperature, water content and particle size are carried out. The variation rules of the permeability characteristics of gas coal under the coupling effect of thermal factors are analyzed, and water content and temperature, water content and effect are derived. The influence mechanism of permeability is discussed and the influence mechanism of permeability is discussed. The three axis percolation test of gas coal with different degree of metamorphism and different sturdy coefficient is carried out. The relationship between the degree of metamorphism of coal and its external pore, the degree of fracture development, the solid coefficient of coal and the initial velocity of gas discharge, and the anti pressure of the three axis are analyzed. A positive pressure regulating valve is added to the outlet of the three axis percolation equipment, and the pore pressure test under the positive pressure of the outlet is carried out. The relationship between the permeability of the gas coal and the pore pressure is obtained. The influence of the pore pressure and the temperature on the permeability of the coal bearing coal under the coupling of the pore pressure and the temperature is analyzed. The pore pressure sensitivity system is defined, and the pore pressure sensitivity system is defined. The relationship between pore pressure sensitivity coefficient and pore pressure is deduced, and the response degree of pore pressure to gas bearing coal permeability.5 is discussed. The existing three axis percolation equipment is improved, and the three axis seepage test of positive pressure, outlet pressure and outlet negative pressure is carried out, and the seepage flow of gas coal with different effective stress and temperature is analyzed. Law, the gas flow velocity and thermal stress, external load, pore pressure and coal skeleton deformation and adsorption mechanism.6) are discussed. The three axis seepage test of negative pressure of export is carried out. The effect of three kinds of negative pressure on gas flow velocity is compared and analyzed, and the mechanism to reduce the negative pressure of the outlet to the gas flow is revealed. On the basis of the optimum negative pressure of the outlet, the influence of the extraction pipe diameter and the length of the extraction pipe on the gas flow velocity of the gas coal is studied. The gas flow velocity of the gas coal increases with the increase of the pipe diameter. With the increase of the temperature and the change law.7 decreasing with the length of the pipeline, the total strain equation of the coal bearing coal system is established, and the slippage is considered. The permeability change model of the effect is combined with the continuity equation of gas flow, the equation of the gas coal deformation balance and the geometric equation. The fluid solid coupling equation containing the stress field and the seepage field and the gas slipping effect is constructed. The correctness of the model is verified by the comparison between the numerical simulation analysis and the physical simulation test. The variation law of gas pressure along the radial distribution and gas phase permeability in coal is compared and analyzed. The drilling of 1# coal seam in the 1# coal seam of Yu she coal mine is a practical example. The variation of gas pressure with the extraction time in the calculated area is analyzed, and the different position of the calculation area is different in the same pumping time. The change trend of gas pressure is revealed, and the evolution law of gas flow in the calculated model under different pumping negative pressure is revealed, and the optimum extraction negative pressure in different stages is discussed.
【學位授予單位】：重慶大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：TD712

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