Experimental study on the movement law of overlying rock non-pillar coal overhead mining

Pillarless coal mining technology is a new practical technology. Based on the compensating mechanical behavior of the Negative Poisson’s Ratio (NPR) anchor cable on the roof, the roadway was successfully retained by the top cutting and pressure relief technology. This study utilizes the Digital Speckle Monitoring (DIC monitoring), stress-strain monitoring, and infrared thermal imaging systems to conduct physical model experiment of similar materials from the displacement, stress-strain, and temperature fields to investigate in depth the fracture change law of the overlying rock. In addition, it uses FLAC3D numerical simulation to invert the surface displacement settlement. The results show that the non-pillar overhead mining under the 110 mining method has little influence on the rock crack in the middle of the coal seam, and the crack development area is mainly concentrated in the overlying rock mass of the upward coal seam. The compensatory mechanical behavior of NPR anchor cable and the dilatation characteristics of rock mass have a good effect of retaining roadway along goaf, and can also reduce surface settlement. The 110 mining method provides a scientific basis for ecological environment protection and the development of other kilometer deep soft rock high ground stress underground projects.