Abstract: This paper introduces the site geotechnical properties of a deep excavation project in Jiangan, Wuhan. Several common excavation supporting methods were compared and the gravity retaining walls consisting of cement mixed soil columns with the reinforcement of passive zone are selected. The results indicate that the design meet the code requirements. The project shows that the selected method has advantages of cost effective and safe construction. The construction recommendations are proposed in the paper.

Key words: Thick Soft Soils, Cement Mixed Column Retaining Wall, Passive , Strengthening, The construction technology；Monitoring