Abstract: In order to solve the floor heave problems in the east rail roadway of Tingnan coal mine, using in-site survey, the physical and chemical composition analysis of surrounding rock, the water softening experiments and numerical analysis methods, the soft rock characteristics, influence factors and deformation mechanics mechanism have been researched. It is concluded that the main reason for the floor heave is mainly due to the strata lithology with weak floor but strong expansibility. Main deformation of roadway and stress release will appear in the bottom when there is no supporting. And the soft rocks in base angle will have large plastic deformation under the stress transfer from both sides of roadway, then extrudes to the center of the floor, forming the floor heave. Hence, corresponding control technology including impermeable base, strengthening, and deformation control is put forward by using the concrete arch-metal welding net-base angle seam pipe bolt support forms. Field monitoring and numerical analysis show that the new support can improve the floor rock mass condition and reduce the base shear deformation.

Key words: floor heave, composite soft rock, deformation mechanism, anti-heave arch, numerical analysis