Floor damage mechanism with cemented paste backfill mining method

Abstract

This paper aims to address the coal seam floor behavior after mining with CPB method. Firstly, the numerical model by using Midas/GTS-Flac3d method is developed on the basis of 2353 working face, Daizhuang Coal Mine; then, the slip line field theory of plastic mechanics is applied to calculate the floor damage depth. Furthermore, field observation is carried out by using water injection method. The results show that the floor deformation is well controlled by using CPB; the tensile zone reduces greatly to one-sixth of the size with traditional caving mining method; the coal seam excavation with CPB mining method is equivalent to reducing the original mining thickness; and the depth of the fracture floor is around 2 ~ 4 m. The numerical simulation and analytical calculation in terms of floor damage depth coincide with the in situ measurement. The proposed analytic model provides insight into the floor behavior with backfilling mining method.