Based on results of ground deformation monitored and the numerical simulation

the process of ground deformation is investigated in East Main Shaft of Chengchao Iron Mine; and then the characteristics and mechanism of ground deformation are given. Research results show that: When the underground mined-out area and the collapse pit form a certain scale

under the release and squeezing of horizontal tectonic stress in different directions

the surrounding rock cut columnar structure cut by geological in structures the surrounding rock toppled to collapse pit

then caused the ground deformation in the surface. Ground deformation is mainly dominated by horizontal displacement

and the vertical displacement is very little. With the constantly tilt of columnar structure

the ratio of vertical displacement to horizontal displacement is constantly increasing

and the funnel-shaped deformation curve forms in the surface.