College of Mining and Coal, Inner Mongolia University of Science and Technology, Baotou, China.
School of Mines, China University of Mining & Technology, Xuzhou, China.
PLoS One. 2022 Sep 27;17(9):e0274209. doi: 10.1371/journal.pone.0274209. eCollection 2022.
The problems of water scarcity and ecological fragility are common in the loess gully area. To research the distribution and evolution of the overburden fissures and quantitatively analyze them have certain theoretical and engineering significance for realizing the evaluation of overburden damage degree and safe and green mining. This paper takes the 6102 working face of Chuancao Gedan Coal Mine as the engineering background. The development law and distribution characteristics of overburden fissures caused by the mining of shallow coal seams in the loess gully area were studied by the combination of physical similarity simulation, numerical similarity simulation and fractal theory. The results show that the fractal dimension change of the overburden fissures caused by the shallow mining of coal seam groups in the loess gully area can be divided into three stages during the mining process of the working face. Repeated mining causes the activation and development of overburden fissures, the fractal dimension increases significantly, and the regularity of changes weakens. The magnitude of the stress near the working face and the fluctuation times of the stress in the goaf have an influence on the change of the fractal dimension of the overburden fissures. According to the development angle and the fractal dimension of the overburden fissures, the overburden rock above the goaf is divided into the collapse fissure area, the compaction fissure area, and the vertical fissure area. Overburden fissures develop violently in the vertical fissure area, the overburden fissures in the compaction fissure area are mostly transverse fissures, and the overburden fissures in the caving fissure area are irregular.
缺水和生态脆弱问题是黄土沟壑区的普遍问题。研究覆岩裂隙的分布和演化，并对其进行定量分析，对于实现覆岩破坏程度的评价和安全绿色开采具有重要的理论和工程意义。本文以串草疙瘩煤矿 6102 工作面为工程背景，采用物理相似模拟、数值相似模拟和分形理论相结合的方法，研究了黄土沟壑区浅埋煤层开采引起的覆岩裂隙的发育规律和分布特征。结果表明，在工作面开采过程中，黄土沟壑区浅埋煤层群开采引起的覆岩裂隙分形维数变化可分为三个阶段。重复开采导致覆岩裂隙的活化和发育，分形维数显著增加，变化规律减弱。工作面附近的应力大小和采空区应力的波动次数对覆岩裂隙分形维数的变化有影响。根据覆岩裂隙的发育角度和分形维数，将采空区上方的覆岩划分为垮落裂隙区、压实裂隙区和垂直裂隙区。垂直裂隙区覆岩裂隙发育剧烈，压实裂隙区覆岩裂隙多为横向裂隙，垮落裂隙区覆岩裂隙不规则。
