Analysis on the Law of Mine Pressure and the Adaptability of Supports in Filling Coal Mining under the Condition of Repeated Mining

Abstract Based on the 31205 filling face in Northern Shaanxi, China, this paper uses the combination of numerical simulation, field measurement and data analysis to analyze the law of overburden stress distribution, the behavior law of periodic pressure and the stress characteristics of support in the process of filling coal mining under repeated mining conditions. Affected by the arch forming effect of the upper working face, the stress of the surrounding rock under the upper coal pillar is obviously concentrated.The roof of the lower coal seam presents the stress characteristics of plate structure, which leads to the obvious increase of the vertical stress of the surrounding rock at the boundary of the lower goaf. However, affected by the upper goaf, the roof support point moves below the upper coal pillar. Under the load transfer action of the upper coal pillar, the lower surrounding rock is prone to plastic failure, resulting in violent movement of the surrounding rock. Compared with the surrounding rock under the goaf, the movement of overburden under the coal pillar is more intense. The periodic pressure law of the working face below the upper coal pillar is different from that of the working face below the upper goaf. Affected by the upper coal seam, the support resistance is asymmetrically distributed, and its maximum support resistance is located below the upper coal pillar.