Abstract
Abstract
In order to study the dynamic evolution law of ground fissures in shallow coal seam mining under ditch，taking the 14210 working face of a mine in northern Shaanxi as an example, this paper analyzes the dynamic development law of ground fissures in the process of mining under ditch through similar material simulation combined with the VIC-3D monitoring system. The results show that there are 20 ground fissures in the 14210 working face. The development width of ground fissures increases first, then decreases rapidly, and finally closes at the bottom of the ditch. The ground uplifts with a height of 1.5 m. The development width of ground fissures increases first, then decreases slightly, and finally tends to stabilize on the left and the right slopes, resulting in staggered steps with a height of 1.6 m and 0.7 m respectively. This change process is consistent with that of the strain of the underlying overburden obtained by VIC-3D strain analysis. According to their development positions and strain changes, the ground fissures are divided into three categories: tensile ground fissures on the left slope T1-T8, squeeze ground fissures at the bottom of the ditch T9-T13, and tensile ground fissures on the right slope T14-T20. Finally the safety analysis of mining under ditch in the 14210 working face is carried out.