摘要
大采高开采技术是我国厚煤层开采的主要技术选择之一,大采高工作面一次割煤高度增大,煤壁稳定性降低,煤壁破坏成为制约该类工作面生产潜能释放的关键因素。为提高大采高工作面围岩稳定性,实现厚煤层高效开采,采用理论分析、室内试验和现场实测等综合手段分析了支架刚度对煤壁稳定性的影响。结果表明:大采高工作面存在3种常见煤壁破坏形式:硬煤劈裂式、中硬煤剪切式和软煤塑性流动式;定义煤壁稳定性系数为煤壁极限承载能力与作用在煤壁之上的顶板载荷之差同顶板载荷之比,得到顶板载荷对稳定性系数分布特征的影响;建立顶板冲击力学模型,基于能量原理,提出了作用于煤壁之上的顶板载荷确定方法;分析了支架刚度对煤壁稳定性系数的影响,随着支架刚度的增加,作用于煤壁之上的顶板载荷降低,煤壁稳定性升高,顶板载荷及煤壁稳定性对支架刚度的敏感性逐渐降低;开展不同支架刚度条件下煤壁稳定性相似模拟试验,支架刚度为1.0、1.5、2.0 MN/m的条件下,煤壁极限承载能力分别为17、19、20 kN,煤壁的最大横向变形量分别为40、30、25 mm,煤壁破坏面积分别为0.41、0.32、0.21 m^(2),试验数据验证了理论分析结果的正确性;最后将提高支架刚度措施应用于乌兰木伦31402大采高工作面,煤壁稳定性得到有效控制。
Longwall mining with large cutting height serves as one of main methods for extracting thick coal seam.Face failure gradually becomes a critical phenomenon due to significant increase of the cutting height,which drastically influences the mining efficiency in such longwall faces.In order to improve surrounding rock stability and mining efficiency of such faces,the influence of support stiffness on face stability is thoroughly investigated by using theoretical analysis,laboratory testing and field measurements.The results show that three kinds of face failure patterns commonly appear in longwall face with large cutting height,including splitting pattern of hard coal seam,shearing pattern of relatively hard coal seam and plastic flow pattern in soft coal seam.A safety factor is proposed for longwall face,which is defined as the ratio of the difference between load-bearing capacity of the face and roof load applied on the face to the referred roof load.The influence of roof load on distribution of the safety factor is obtained.A model is developed for roof impact phenomenon,determination method of the load exerting on the face by roof is deduced.The relation between support stiffness and face stability coefficient is achieved.With the increase in support stiffness,the load applied on the face decreases and the face stability is strengthened.However,the sensitivity of the load and face stability to support stiffness decreases gradually.Physical modeling of the influence provided by support stiffness on face stability is carried out.With the support stiffness of 1.0,1.5 and 2.0 MN/m,load-bearing capacity of the face increases from 17 to 19 and then to 20 kN.The largest horizontal displacement decreases from 40 to 30 and then to 25 mm.After failure,the broken areas are about 0.41,0.32 and 0.21 m^(2),respectively,in the referred scenarios.At last,the face stability of 31402 longwall face in Wulanmulun coal mine is effectively improved by increasing the support stiffness.
作者
韩宇峰
王兆会
唐岳松
HAN Yufeng;WANG Zhaohui;TANG Yuesong(School of Civil Engineering,Liaoning Technical University,Fuxin 123000,China;School of Energy and Mining Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China)
出处
《煤炭科学技术》
CAS
CSCD
北大核心
2023年第3期1-9,共9页
Coal Science and Technology
基金
国家自然科学基金青年基金资助项目(51904304)
国家重点研发计划资助项目(2017YFC0603002)。
关键词
大采高工作面
煤壁破坏
厚煤层开采
煤壁压力
支架刚度
longwall face with large cutting height
face failure
thick coal seam mining
face load
support stiffness