Layouts of measuring point and baseline of the surrounding rock convergence observation in complicated rock mass structure

The conventional layouts of measuring point and baseline of the surrounding rock convergence observation in complicated rock mass may not be very rational by reason that the monitoring data from unapparent, sites will not indicate the real deformation rules. A case study on a gypsum mine with low-angle and thin layers is conducted. Them typical failure pattern of surrounding rock mass structure is analyzed according to the investigation into the stope pollapse scene, then the main tasks of convergence observation are determined to understand the bending and separation rules of roof and floor and shear slipping rule of pillar. Discrete element method (DEM) is applied to choose the key sites with notable displacement feature as best ones of convergence point, which can reflect the initial failure zone of surrounding rock. Based on the deformation rule of selected points, the layout of baseline is further optimized and the displacement formula is also presented.