Model test study of zonal disintegration phenomenon (ZDP) in deep rock mass under hydrostatic pressure

Abstract

The zonal disintegration phenomena (ZDP) will appear with the increasing of the depth of underground engineering which are different from shallow tunnel. In order to investigate the formation mechanism and influence factor of ZDP, taking the deep tunnel of Dingji coal mine with high geostress as background, the true 3D geomechanical model tests under hydrostatic pressure have been carried out by adopting model similar materials and numerical controlling true 3D loading model test system. The model test results show that: (1) Only when the geostress satisfies certain stress conditions, the ZDP will appear under hydrostatic pressure. (2) Geostress is an important influence factor for ZDP of rock mass under hydrostatic pressure. The radial displacements of surrounding rock increase obviously because of high geostress. The higher value of geostress is, the larger range of fractured zone is. (3) The changing laws of displacements of the surrounding rocks by means of advanced and exact measurement method are obtained. The results of displacements and the distribution of fractured areas are basically consistent. The model test results help to reveal the influence factor of ZDP, which lays a solid test foundation for further studying nonlinear deformation characteristics and failure mechanism of deep rock mass.