To determine the rational layout parameters of the lateral high drainage roadway(LHDR) serving for two adjacent working faces, a mechanical model of the LHDR under mining influence was established, and the overburden ...To determine the rational layout parameters of the lateral high drainage roadway(LHDR) serving for two adjacent working faces, a mechanical model of the LHDR under mining influence was established, and the overburden fissure, mining-induced stress distribution rules were analyzed. First, the development characteristics of mining-induced overburden fissure and the stress distribution law of the upper section of the working face were analyzed. Second, by analyzing the distribution law of vertical stress at different layers, the lateral distance of the LHDR was determined as 25 m. Third, by analyzing the surrounding rock deformation effect, stress distribution law, and overburden fissure distribution law of the LHDR at the heights of 20, 25, and 30 m away from the roof, the rational horizon of the LHDR was determined to be 25 m. Finally, an example of a LHDR located 25 m above the roof of the No. 2 coal seam and 25 m away from the No. 2-603 working face was presented. Results show that when the No. 2-603 coalface is being mined, the surrounding rocks lag 80 m or even further and the working face tends to be stable. The relative deformations of the roof and floor of the roadway and both of its walls were 583 and 450 mm,respectively. The reduction rate of the roadway section was 21.52%–25.32%. The section of the roadway was sufficient to extract the pressure relief gas in the overburden of the No. 2-605 working face. The average gas concentration and the pure volume at the branch pipeline were 24.8% and 22.3 m^3/min,respectively, showing that the position of high-level boreholes was reasonable.展开更多
The relatively high stress probably leads to generation of a fractured or even instable area around a working coalface. Also, the generated weak area often evolves into an easy-infiltrating field of water/gas to great...The relatively high stress probably leads to generation of a fractured or even instable area around a working coalface. Also, the generated weak area often evolves into an easy-infiltrating field of water/gas to greatly increase probability of accident occurrence. To reveal the distribution of high stress around working faces, we put forward the mode-I-crack compression model. In this model, the goaf following a working face is regarded as a mode-I crack in an infinite plate, and the self-gravity of overlaying strata is transformed into an uniform pressure applied normal to the upper edge of the model crack. Solving this problem is based on the Westergaard complex stress function. For comparison, the software RFPA-2D is also employed to simulate the same mining problem, and furthermore extendedly to calculate the stress interference induced by the simultaneous advances of two different working faces. The results show that, the area close to a working face or the goaf tail has the maximum stress, and the stress is distributed directly proportional to the square root of the advance and inversely proportional to the square root of the distance to the working face. The simultaneous advances of two neighboring working faces in different horizontals can lead to extremely high resultant stress in an interference area.展开更多
以提高瓦斯抽采效果为目标,某矿Ⅲ4423工作面为研究对象,采用理论分析、数值模拟、现场试验等研究方法,研究了顶板高位钻孔条件下瓦斯抽采的主要技术参数,数值模拟出高位钻孔抽采瓦斯前采空区的瓦斯分布情况与运移规律,以及负压分别为8...以提高瓦斯抽采效果为目标,某矿Ⅲ4423工作面为研究对象,采用理论分析、数值模拟、现场试验等研究方法,研究了顶板高位钻孔条件下瓦斯抽采的主要技术参数,数值模拟出高位钻孔抽采瓦斯前采空区的瓦斯分布情况与运移规律,以及负压分别为8、10 k Pa时的高位钻孔瓦斯抽采效果。依据瓦斯流动"O"型圈理论与FLUENT数值模拟分析,优化设计高位钻孔抽采瓦斯工艺参数并进行现场试验。结果表明:当高位钻孔抽采负压为8 k Pa、终孔位置调整到采空区裂隙带回风巷侧15~35 m范围内时,高位钻孔抽采瓦斯效果最佳,采空区内瓦斯最高浓度明显降低,单个钻场最大抽采瓦斯量为19 821.74 m^3,钻孔瓦斯浓度稳定在20%~30%之间,最大值达到50%,实现了工作面有效治理瓦斯和安全生产的目标。展开更多
基金National Key Basic Research Program of China (973 Program) (No. 2015CB251600)the National Natural Science Foundation of China (Nos. 51327007, 51174157, and 51104118) for their support of this project
文摘To determine the rational layout parameters of the lateral high drainage roadway(LHDR) serving for two adjacent working faces, a mechanical model of the LHDR under mining influence was established, and the overburden fissure, mining-induced stress distribution rules were analyzed. First, the development characteristics of mining-induced overburden fissure and the stress distribution law of the upper section of the working face were analyzed. Second, by analyzing the distribution law of vertical stress at different layers, the lateral distance of the LHDR was determined as 25 m. Third, by analyzing the surrounding rock deformation effect, stress distribution law, and overburden fissure distribution law of the LHDR at the heights of 20, 25, and 30 m away from the roof, the rational horizon of the LHDR was determined to be 25 m. Finally, an example of a LHDR located 25 m above the roof of the No. 2 coal seam and 25 m away from the No. 2-603 working face was presented. Results show that when the No. 2-603 coalface is being mined, the surrounding rocks lag 80 m or even further and the working face tends to be stable. The relative deformations of the roof and floor of the roadway and both of its walls were 583 and 450 mm,respectively. The reduction rate of the roadway section was 21.52%–25.32%. The section of the roadway was sufficient to extract the pressure relief gas in the overburden of the No. 2-605 working face. The average gas concentration and the pure volume at the branch pipeline were 24.8% and 22.3 m^3/min,respectively, showing that the position of high-level boreholes was reasonable.
基金Projects 50774083 and 40811120546 supported by the National Natural Science Foundation of ChinaNCET-07-0803 by the Program for New Century Ex-cellent Talents in University 2005CB221502 by the National Basic Research Program of China
文摘The relatively high stress probably leads to generation of a fractured or even instable area around a working coalface. Also, the generated weak area often evolves into an easy-infiltrating field of water/gas to greatly increase probability of accident occurrence. To reveal the distribution of high stress around working faces, we put forward the mode-I-crack compression model. In this model, the goaf following a working face is regarded as a mode-I crack in an infinite plate, and the self-gravity of overlaying strata is transformed into an uniform pressure applied normal to the upper edge of the model crack. Solving this problem is based on the Westergaard complex stress function. For comparison, the software RFPA-2D is also employed to simulate the same mining problem, and furthermore extendedly to calculate the stress interference induced by the simultaneous advances of two different working faces. The results show that, the area close to a working face or the goaf tail has the maximum stress, and the stress is distributed directly proportional to the square root of the advance and inversely proportional to the square root of the distance to the working face. The simultaneous advances of two neighboring working faces in different horizontals can lead to extremely high resultant stress in an interference area.
文摘以提高瓦斯抽采效果为目标,某矿Ⅲ4423工作面为研究对象,采用理论分析、数值模拟、现场试验等研究方法,研究了顶板高位钻孔条件下瓦斯抽采的主要技术参数,数值模拟出高位钻孔抽采瓦斯前采空区的瓦斯分布情况与运移规律,以及负压分别为8、10 k Pa时的高位钻孔瓦斯抽采效果。依据瓦斯流动"O"型圈理论与FLUENT数值模拟分析,优化设计高位钻孔抽采瓦斯工艺参数并进行现场试验。结果表明:当高位钻孔抽采负压为8 k Pa、终孔位置调整到采空区裂隙带回风巷侧15~35 m范围内时,高位钻孔抽采瓦斯效果最佳,采空区内瓦斯最高浓度明显降低,单个钻场最大抽采瓦斯量为19 821.74 m^3,钻孔瓦斯浓度稳定在20%~30%之间,最大值达到50%,实现了工作面有效治理瓦斯和安全生产的目标。
