摘要
针对我国西部矿区浅埋厚煤层下采煤易出现矿压剧烈、地表沉陷破坏严重等现象,以西部某矿22021工作面为研究背景,提出了浅埋厚煤层下的“斜台阶切落体”结构力学模型,得到了结构失稳的条件方程和求解支护力大小的公式,通过PFC数值模拟和工程应用进行了验证,并分析了该结构对覆岩采动裂缝发育规律的影响。结果表明:影响“斜台阶切落体”结构稳定性的主要因素为岩块块度和回转角,该结构的稳定性会直接影响覆岩采动裂缝的发育情况。煤层开采过程中,覆岩采动裂缝发育表现为斜角度延伸及周期性横向扩展特征,“斜台阶切落体”结构失稳前,裂缝发育阶段处于缓慢增长期,结构失稳后会导致覆岩采动裂缝数量出现断崖式增长,发育阶段进入急剧增长期,结构稳定性直接影响了覆岩采动裂缝的发育情况,从而影响地表沉陷的破坏情况。覆岩采动裂缝数量先后经历了1个缓慢增长期和4个急剧增长期的动态发育过程。在缓慢增长期,裂缝数量表现为随工作面推进距离增长的指数变化关系;在急剧增长期,裂缝数量表现为随工作面推进距离增长的线性变化关系。研究结果可为采动损害防护及地表生态修复提供依据。
In view of the phenomenon that mining under shallow buried thick coal seam in western mining area of China is prone to severe mine pressure and serious surface subsidence damage, with the 22021 working face of a mine in western China as the research background, the structural mechanics model of “inclined step cutting body” under shallow buried thick coal seam was proposed, and the conditional equation of structural instability and the formula for solving the size of support force were obtained.The PFC numerical simulation and engineering application were verified, and the influence of this structure on the development law of overlying rock mining-induced cracks was analyzed.The results show that the main factors affecting the structural stability of the “inclined step cutting body” are rock block size and rotation angle, and the stability of the structure directly affects the development of overlying rock mining-induced cracks.In the process of coal seam mining, the development of overlying rock cracks is characterized by oblique angle extension and periodic lateral extension.Before the structural instability of “inclined step cutting body”,the development stage of the cracks is in a slow growth period.After the structural instability, the number of mining-induced cracks in weathered rock increases sharply, and the development stage enters a period of rapid growth.The structural stability directly affects the development of mining-induced cracks in weathered rock, thereby affecting the destruction of surface subsidence.The number of overlying rock mining-induced cracks has experienced a slow growth period and four rapid growth periods.In the slow growth period, the number of cracks shows an exponential relationship with the increase of working face advancing distance.In the rapid growth period, the number of cracks shows a linear relationship with the increase of working face advancing distance.The research results provide a basis for mining damage protection and surface ecological restoration.
作者
张琰君
阎跃观
朱元昊
孔嘉嫄
ZHANG Yanjun;YAN Yueguan;ZHU Yuanhao;KONG Jiayuan(School of Geoscience and Surveying Engineering,China University of Mining and Technology,Beijing 100083,China)
出处
《太原理工大学学报》
CAS
北大核心
2023年第1期91-97,共7页
Journal of Taiyuan University of Technology
基金
中央高校基本科研业务费专项资金资助项目(2022YJSDC20)。
关键词
浅埋厚煤层
斜台阶切落体
裂缝
颗粒流
shallow buried thick coal seam
inclined step cutting body
cracks
particle flow
