Study on the Influence of Overlying Coal Seam Mining on the Deformation of Floor Roadway Surrounding Rock

The roadway is the lifeline of the underground production system of the coal mine. Once deformation and damage occur, it can easily lead to mining disasters. After the coal seam is mined, the distribution of the original stress field is changed, and a new mining stress field is generated, which causes the surrounding rock of the roadway at the bottom of the coal seam to be affected to varying degrees. This paper takes the Lu Ling coal mine in China as the research object, and uses the method of combining similarity simulation test and numerical simulation to study the surrounding stress and deformation damage of the floor roadway with the mining of the main coal seam in Luling Coal Mine. The results show that under the action of tectonic stress, with the mining of the overlying main coal seam, the stress concentration and plastic damage of the roof and floor of the roadway in the coal seam floor are relatively small, while the pressure relief and plastic damage of the two sides are relatively large in Luling Coal Mine. To verify the influence of different mining dynamic stresses on the deformation and damage of roadway, mining simulations were conducted under both structural stress and self weight stress conditions. The results showed that the collapse shape of the roof was significantly different under different stress fields, and the stress evolution law of the mining floor was also different. Under the main control of structural stress, the total body of the floor was mainly under compressive stress, while under the main control of self weight stress, it was significantly affected by the unloading of the overlying goaf, mainly under tensile stress, resulting in significantly different forms of roadway failure. This study can provide reference for the stability analysis and support of surrounding rock in mine roadway with different geostress.