Application and research on prediction method for mining subsidence inshallow buried deep coal seam

The problem of surface subsidence caused by coal mining has always been one of the key technical problems to be solved urgently. In order to clarify the law of overburden strata and surface subsidence of the working face under the condition of shallow buried strata, the practical problems faced by No. 5 coal seam mining were taken as the research background, the combination of theoretical calculation, numerical simulation and field measurement were used to research the laws of surface subsidence rule and its influence on surface buildings protected areas in No.5-210 mining face and its influence on the buildings in the surface protection area were studied.Based on the relationship between the stress-swelling coefficient of the rock mass and the basic principle of mining subsidence,the surface subsidencemodel was established, and the surface subsidence law after mining was predicted theoretically, with the maximum subsidence of 2.604 m.Using FLAC3D numerical simulation software, the numerical calculation model of surface subsidence in the working face was established, and and the post-processing of simulation results is carried out by Tecplot software.The simulated maximum surface subsidence was 2.78 m,and the maximum subsidence point was located at the center of the working face. According to the ground surface subsidence control benchmark, the geometrical relationship is used to calculate the influence range of the surface subsidence and the reasonable boundary of the working surface layout.The No.5-210 working face was arranged at the southwing of +830 m working level in the mine field, andit is connected with the belt entry in the south of 830 level in the west and reaches the boundary of the mine field in the east. In addition, the field measurement of surface movement and subsidence during mining was carried out, and the GPS receiver was used to collect real-time RTK data. The monitoring results showed that the maximum surface subsidence was 2.69 m, and the surface subsidence area in the gob did not affect the safety of the buildings in the industrial square. Based on the combination of theoretical calculation and numerical simulation, the reasonable position and spatial layout of No.5-210 working face were designed, and good practical results were obtained, which provides a reliable basis for predicting surface subsidence of gob under similar geological conditions.