In order to obtain a gas seepage law of deep mined coal seams, according to the properties of coalbed methane seepage in in-situ stress and geothermal temperature fields, the gas seepage equation of deep mined coal se...In order to obtain a gas seepage law of deep mined coal seams, according to the properties of coalbed methane seepage in in-situ stress and geothermal temperature fields, the gas seepage equation of deep mined coal seams with the Klinkenberg effect was obtained by confirming the coatbed methane permeability in in-situ stress and geothermal temperature fields. Aimed at the condition in which the coal seams have or do not have an outcrop and outlet on the ground, the application of the gas seepage equation of deep mined coal seams in in-situ stress and geothermal temperature fields on the gas pressure calculation of deep mined coal seams was investigated. The comparison between calculated and measured results indicates that the calculation method of gas pressure, based on the gas seepage equation of deep mined coal seams in in-situ stress and geothermal temperature fields can accu- rately be identical with the measured values and theoretically perfect the calculation method of gas pressure of deep mined coal seams.展开更多
针对双向非等压应力场上向长距离瓦斯抽采钻孔密封长度难以确定、现场封孔难度大的问题,以平煤六矿为工程背景,以弹塑性理论和Mohr-Coulomb准则为基础,得出圆形巷道非等压应力场下塑性区边界方程,通过FLAC3D数值模拟映证了理论分析结果...针对双向非等压应力场上向长距离瓦斯抽采钻孔密封长度难以确定、现场封孔难度大的问题,以平煤六矿为工程背景,以弹塑性理论和Mohr-Coulomb准则为基础,得出圆形巷道非等压应力场下塑性区边界方程,通过FLAC3D数值模拟映证了理论分析结果:当侧压系数不为1时,巷道围岩塑性区边界是对称的"蝴蝶形",不再是等压力应力场下的圆形,且巷道围岩应力呈非均匀分布,应力沿巷道径向变化的梯度和围岩应力降低区的范围沿不同角度时也存在明显差异;理论分析和数值模拟计算的塑性区深度偏差小于5%。结合塑性区的变化规律确定了不同角度上向穿层钻孔的密封长度,提出更具针对性的新型逐级注浆封孔技术。瓦斯抽采试验表明:按照本文确定的密封长度对上向穿层钻孔进行密封时,孔内抽采负压均在13 k Pa以上,最高瓦斯抽采浓度是传统等压应力场下对比试验孔的1.4倍,且其衰减速率较慢,瓦斯抽采效果可以满足长期高效抽采的要求。展开更多
以淮南煤矿典型工作面为例,采用离散元数值软件UDEC(universal distinct element code)对工作面回采过程中上下煤岩体内应力场的变化及直接顶冒落过程进行了模拟,分析了上覆煤岩体裂隙产生、发展的形成过程,得到了上覆煤岩裂隙演化规律...以淮南煤矿典型工作面为例,采用离散元数值软件UDEC(universal distinct element code)对工作面回采过程中上下煤岩体内应力场的变化及直接顶冒落过程进行了模拟,分析了上覆煤岩体裂隙产生、发展的形成过程,得到了上覆煤岩裂隙演化规律。研究结果表明,倾向方向工作面回采后,上覆煤岩体内产生冒落、裂隙带和离层带,在工作面内上角位置产生O型圈裂隙带,裂隙发育最大高度为45 m。煤层走向回采方向得到了初期来压步距约50 m,周期来压步距约20 m,上覆煤岩体裂隙在采空区上方约呈45°角发展,并随工作面的前进由下向上、由后往前依次演变。该结果对于煤与瓦斯共采中瓦斯抽放钻孔方位的布置具有工程指导意义。展开更多
基金support of the Open Fund of State Key Laboratory of Oil and Gas Reser-voir Geology and Exploitation (Southwest Petroleum University) (PLN0610)the Opening Project of He-nan Key Laboratory of Coal Mine Methane and Fire Prevention (HKLGF200706)+3 种基金 the National Natural Science Foundation of China (No. 50334060, 50474025, 50774106)the National Key Fundamental Research and Development Program of China (No. 2005CB221502)the Natural Science Innovation Group Foundation of China (No. 50621403)the Natural Science Foundation of Chongqing of China(No. CSTC, 2006BB7147, 2006AA7002).
文摘In order to obtain a gas seepage law of deep mined coal seams, according to the properties of coalbed methane seepage in in-situ stress and geothermal temperature fields, the gas seepage equation of deep mined coal seams with the Klinkenberg effect was obtained by confirming the coatbed methane permeability in in-situ stress and geothermal temperature fields. Aimed at the condition in which the coal seams have or do not have an outcrop and outlet on the ground, the application of the gas seepage equation of deep mined coal seams in in-situ stress and geothermal temperature fields on the gas pressure calculation of deep mined coal seams was investigated. The comparison between calculated and measured results indicates that the calculation method of gas pressure, based on the gas seepage equation of deep mined coal seams in in-situ stress and geothermal temperature fields can accu- rately be identical with the measured values and theoretically perfect the calculation method of gas pressure of deep mined coal seams.
文摘针对双向非等压应力场上向长距离瓦斯抽采钻孔密封长度难以确定、现场封孔难度大的问题,以平煤六矿为工程背景,以弹塑性理论和Mohr-Coulomb准则为基础,得出圆形巷道非等压应力场下塑性区边界方程,通过FLAC3D数值模拟映证了理论分析结果:当侧压系数不为1时,巷道围岩塑性区边界是对称的"蝴蝶形",不再是等压力应力场下的圆形,且巷道围岩应力呈非均匀分布,应力沿巷道径向变化的梯度和围岩应力降低区的范围沿不同角度时也存在明显差异;理论分析和数值模拟计算的塑性区深度偏差小于5%。结合塑性区的变化规律确定了不同角度上向穿层钻孔的密封长度,提出更具针对性的新型逐级注浆封孔技术。瓦斯抽采试验表明:按照本文确定的密封长度对上向穿层钻孔进行密封时,孔内抽采负压均在13 k Pa以上,最高瓦斯抽采浓度是传统等压应力场下对比试验孔的1.4倍,且其衰减速率较慢,瓦斯抽采效果可以满足长期高效抽采的要求。
