This paper aims at the study of 3D numerical simulation of the groundwater flow field of the Changzhou-Wujin district

for revealing the main cause of the depression of the ground surface. First

the hydro-geological conditions of this area are analyzed. Based on this

a 3D numerical model of the groundwater flow field of the second confined aquifer is established. Then the numerical solution of this model is found using the 3D finite difference method. And finally

the 3D dynamic visualization of the groundwater flow field is realized using the hybrid rendering algorithm of the volume rendering combined with the techniques of computer animation. Through this study

it has been found that the main mined layer is the second confined aquifer of this district and its long term over exploitation is the main reason for giving birth to the cones of depression of the groundwater and the depression of the ground surface; the centers of the cones of depression of the groundwater are mainly distributed along the Shanghai-Nanjing railway where the industry and agriculture are flourishing and is heavily populated; the range of the depression of the ground surface and that of the cones of depression of the groundwater are basically identical

and the depression intensity and the depression rate of the ground surface are much related to the falling extent and the falling rate of the groundwater level. However

the phenomenon of the rebound of the ground surface is not prominent

when the groundwater level rises to great extent

that means the process of the depression of the ground surface is basically irreversible. Therefore

it is absolutely necessary to strictly control the mining amount of the groundwater of the second confined aquifer of this district

so as to avoid the further deterioration of the environmental geological catastrophes.