基于FLAC3D的煤矿开采诱发地表沉降研究

Study on Surface Subsidence Induced by Coal Mining Based on FLAC3D

摘要: 煤矿开采会导致周边岩体的初始应力状态被打破，从而诱发地表及其上覆岩层的沉降。基于FLAC3D对河南某煤矿开采过程进行模拟。分析了煤炭开采引起地表及上覆岩层的沉降变化规律。煤矿开采后，初始应力状态发生变化，在竖直方向上主要是压应力，在开采区域顶部和底板出现应力降低区，而在左右煤壁和后壁处出现压应力集中。沉降量始终关于模型中轴线即采空区中心呈对称分布，沉降量最大值始终处于采空区中心以上，距采空区中心距离越远，沉降量越小。分步开挖的整个过程中，随着开采长度的增加，除了底部隆起之外，其他部位的沉降量都在增大，而底部隆起量也在增加。开采完成后，区域内最大沉降量达到354.94 mm，地表最大沉降量为42.1 mm。

Abstract: Coal mining disrupts the initial stress state of the surrounding rock mass, thereby inducing subsidence in the surface and overlying strata. Based on FLAC3D, the mining process of a coal mine in Henan Province was simulated. This study analyzes the patterns of surface and overlying strata subsidence caused by coal extraction. After mining, the initial stress field is redistributed, characterized primarily by compressive stress in the vertical direction. A stress reduction zone appears at the roof and floor of the mined-out area, while stress concentration zones with high compressive stress emerge at the left/right coal walls and the rear wall. The subsidence profile is always symmetrically distributed about the central axis of the model, i.e., the center of the goaf. The maximum subsidence value consistently occurs directly above the center of the goaf, and the magnitude of subsidence decreases with increasing distance from this center. Throughout the sequential excavation process, as the mining length increases, the subsidence values increase in all areas except for the heave (upward movement) at the base, although the magnitude of this basal heave also increases. Upon completion of mining, the maximum subsidence within the domain reached 354.94 mm, and the maximum surface subsidence was 42.1 mm.