Abstract: Based on the hardening-soil model, finile element analyzing method was carried out on supporting system of gravity retaining wall with embedded H-shaped steel through PLAXIS FEM software; and researches was conducted on the deformation and stability of the support system with the simulation results and on-site monitoring data. Researches show that (1) Gravity retaining wall with H-shaped steel shows good feasibility and engineering functions in the range of 7-8 m of local excavation of shallow foundation pit, which can be the supplementary means of gravity-style enclosure. (2) Good precision and results close to actual situations can be obtained by hardening-soil model(HS model for short) embedded in PLAXIS FEM software to simulate the foundation pit, and parameters of HS model can be obtained according to engineering experience. (3) On-site monitoring data of foundation pit shows that the displacement development of gravity retaining wall with H-shaped steel was controlled under the restriction of retaining wall on both ends, which is good for global stability; and that H-shaped steel can well improve the stiffness of supporting system and resist some of bending moment produced by soil mechanics, which to some extent controlled the support system’s displacement. (4) In actual engineering local excavating depth of gravity retaining wall with H-shaped steel should be carefully chosen, which is advisably used under the condition of loose requirement for surroundings’ protection, with a advisable excavating depth of 7-8 m in local foundation excavation and the global excavating depth of 5-6 m. Through the research of gravity retaining wall support with H-shaped steel in shallow foundation pit in soft soil area, more reliable technique supports can be offered for relevant supporting engineering of foundations.

Key words: cement-soil mixing pile, gravity retaining wall, soft soil foundation pit, deformation and stability, H-shaped steel, PLAXIS software