Research on overburden failure and land subsidence characteristics of double coal seam mining in Yushenfu Mining Area

Abstract

In order to study the overburden failure characteristics and surface subsidence law of shallow buried coal seam under the condition of double coal seam mining, based on the geological conditions of typical shallow buried coal seam in Yushenfu Mining Area, the numerical simulation method was used to analyze the overburden failure and surface subsidence characteristics under six different working conditions, and the physical similarity simulation experiment was used to verify. The results show that the failure mode of shallow buried coal seam is full-thickness cutting, and the mining-induced failure in the water-resisting layer in the retained coal pillar mining presents the “mud cover effect”. When the coal pillar is not retained, the two sides of the goaf form the development zone of separated cracks, and the cracks develop about 45° above the two sides of the goaf. The surface subsidence is stepped when the coal seam is mined. With the advance of the working face, the surface subsidence center moves forward continuously, and the influence of the weight of the aquifer on the surface subsidence is gradually reduced. The thickness of the coal seam is positively correlated with the surface subsidence value. There is stress concentration in the process of coal seam mining. The vertical stress in the overlying strata appears stress concentration area, stress relief area and stress concentration area successively along the direction of coal seam mining.

Keywords

• shallow buried coal seam
• numerical simulation
• overburden failure
• surface subsidence
• physical similarity simulation