Su Hengyu, Luo Chang, Jia Yichao, Wang Ziyi
Guizhou Minzu University, Guiyang, 550025, Guizhou, China.
Guizhou University, Guiyang, 550025, Guizhou, China.
Sci Rep. 2023 Sep 7;13(1):14715. doi: 10.1038/s41598-023-41505-7.
The strip structure filling mining technology is suggested in response to the environmental issues such as surface subsidence and landslides brought on by the mining of 11,071 working faces in a mine in Guizhou. The mining technology system is studied through indoor testing, numerical simulation, and engineering monitoring. According to theoretical study, the filling strip can be steadily loaded and its value doesn't exceed 10 m when the width of the filling strip and the width of the filling interval are set to be equal. According to laboratory testing, fly ash can replace some of the cement in the cement mixture as a binder to maintain strength while cutting costs. The degree of crystallization gradually distributed into the network in the filling paste of various ages corresponds to its strength when combined with the findings of scanning electron microscopy; The numerical simulation results show that the maximum subsidence of the immediate roof is reduced from 340 to 3 mm from the filling rate of 0 to 100%, the filling effect is remarkable, and the shape of the settlement curve is changed from 'U' to 'basin', then to 'W'; during the local filling mining, the settlement curve of the immediate roof presents a 'wave' shape, and the stress curve of the immediate roof in the middle of the stope is also changed. The peak tension of the coal wall falls synchronously with filling spacing on both sides of the stope. The overall vertical stress below the mountain is larger, and the vertical stress at the top of the filling body eventually shifts from a "saddle" shape to a "inverted U" shape without zero support stress. In conjunction with the plastic zone, it is discovered that the stable bearing of the "filling strip-direct roof" composite structure increases with decreasing tensile and shear damage range of the hollow roof area and both sides of the top of the "filling 3 m interval 3 m" scheme; engineering measurement also reveals that the higher the position of the survey line is, the smaller the displacement is. However, the overall displacement of the strata directly above is negligible, and the greatest displacement is only 10.9 mm, which is consistent with the numerical simulation. At the same time, the displacement beneath the mountain area is too great.
针对贵州某矿11071个工作面开采引发的地表沉陷、山体滑坡等环境问题，提出条带结构充填开采技术。通过室内试验、数值模拟和工程监测对该开采技术体系进行研究。理论研究表明，当充填条带宽度与充填间隔宽度相等时，充填条带可稳定承载，其值不超过10m。室内试验表明，粉煤灰可作为胶凝材料替代水泥混合料中的部分水泥，在降低成本的同时保持强度。结合扫描电子显微镜的结果发现，不同龄期充填膏体中逐渐分布成网络状的结晶程度与其强度相对应；数值模拟结果表明，随着充填率从0%提高到100%，直接顶的最大下沉量从340mm减小到3mm，充填效果显著，沉降曲线形状从“U”形变为“盆”形，再变为“W”形；在局部充填开采时，直接顶的沉降曲线呈“波浪”形，采场中部直接顶的应力曲线也发生变化。煤壁的峰值拉力与采场两侧的充填间距同步下降。山体下方的整体垂直应力较大，充填体顶部的垂直应力最终从“马鞍”形转变为“倒U”形，不存在零支撑应力。结合塑性区发现，“充填条带-直接顶”复合结构的稳定承载能力随着“充填3m间隔3m”方案中空顶区及顶部两侧拉伸和剪切破坏范围的减小而增加；工程测量还表明，测量线位置越高，位移越小。然而，上方地层的整体位移可忽略不计，最大位移仅为10.9mm，与数值模拟结果一致。同时，山体下方区域的位移过大。
