State Key Laboratory of Coal Resources and Safe Mining, China University of Mining & Technology, Xuzhou, Jiangsu 221116, China; School of Mines, China University of Mining & Technology, Xuzhou, Jiangsu 221116, China.
State Key Laboratory of Coal Resources and Safe Mining, China University of Mining & Technology, Xuzhou, Jiangsu 221116, China; School of Mines, China University of Mining & Technology, Xuzhou, Jiangsu 221116, China.
Sci Total Environ. 2023 Sep 15;891:164693. doi: 10.1016/j.scitotenv.2023.164693. Epub 2023 Jun 7.
Caving mining method could lead to massive waste rocks hauled to surface while leaving a large void in underground. This would eventually result in the surface subsidence and damage to the environment and surface infrastructures. In this study, we proposed three different backfilling methodologies to minimise the surface subsidence being 1) 100 % mining and 100 % backfilling (method 1); 2) leaving one slice of coal between two backfilled slices (method 2) and 3) leaving one slice of coal between one backfilled slice (method 3). The backfilling materials are made of waste rock, fly ash and cement and the optimal ratio has been found through the test program designed based on the orthogonal experiment design method. The strength of the backfilling paste is 3.22 MPa at the axial strain 0.033. The mine scale numerical simulation has also been conducted and it was concluded that the method 1 would lead to 0.098 m roof deformation in underground roadway whereas the method 2 and method 3 only induced a roof deformation around 32.7 % and 17.3 % of that induced by the method 1, respectively. All three methodologies have been approved to minimise the roof deformation and disturbance to the rock by mining operations. At last, the surface subsidence has been scientifically evaluated based on the probability integration method of surface movement. It indicated that the surface subsidence, horizontal movement, inclined movement and curvature of rock surrounding the panel void were all below the minimum value required by regulation. This confirmed that the selected backfilling mining is able to ensure the integrity of the surface infrastructures. This technology provides a new way to control the surface subsidence caused by coal mining.
地下开采会将大量废石运至地表，同时在地下留下一个巨大的空洞。这最终会导致地表沉降，破坏环境和地表基础设施。在这项研究中，我们提出了三种不同的充填方法，以最小化地表沉降，分别是 1）100%开采和 100%充填（方法 1）；2）在两个充填层之间留下一片煤（方法 2）；3）在一个充填层之间留下一片煤（方法 3）。充填材料由废石、粉煤灰和水泥组成，通过基于正交试验设计方法的试验方案，找到了最佳比例。充填浆体的强度在轴向应变为 0.033 时为 3.22 MPa。还进行了矿山规模的数值模拟，结果表明，方法 1 会导致地下巷道顶变形 0.098m，而方法 2 和方法 3 仅导致顶变形分别为方法 1 的 32.7%和 17.3%左右。所有三种方法都被批准用于最小化采矿作业对顶板变形和围岩的干扰。最后，基于地表移动概率积分法对地表沉降进行了科学评价。结果表明，面板空洞周围的地表沉降、水平移动、倾斜移动和曲率均低于法规要求的最小值。这证实了所选的充填开采能够确保地表基础设施的完整性。这项技术为控制采煤引起的地表沉降提供了一种新的方法。
