Based on a deep foundation pit in water-rich silt stratum inside a subway station test section of Taiyuan, the numerical calculation software FLAC3D was adopted to simulate the bottom reinforcement, pit precipitation and excavation. The calculation results were compared and validated with the field measured data. It shows that the high-pressure jet grouting combined with double liquid grouting can effectively prevent groundwater from seepage into the pit, and the groundwater level around the foundation pit varies little during the whole construction process. During foundation pit excavation, the maximum settlement point nearby is located at about 5.m to 10.m away from the underground diaphragm wall, and the maximum influence range is less than twice of the excavation depth. In each excavation stage, the deformation of diaphragm wall presents a parabolic form of high in the middle and low on both ends and the maximum lateral displacement is 22.1.mm, located at 1/2 to 2/3 of the excavation depth. Increasing the elastic modulus of soil can significantly suppress the uplift deformation at the bottom of the pit, but has little influence on the surface settlement around the foundation pit and the horizontal displacement of the diaphragm wall. Therefore, it is not advisable to blindly increase the cement content to avoid waste in actual construction. Keywords: water-rich soft ground；deep foundation pit；combination grouting；groundwater seepage；FLAC3D；elasticity modulus 〖FL