Abstract: In order to explore a green and economical solution for the small shallow basement excavations in thick soft soils, different types of deep excavation support methods are compared and analyzed in a single story basement foundation excavation project in Hanchuan. An economical and reasonable supporting system is designed by using the soil mixing wall (SMW) method as supporting structure and the soil-cement column reinforcement in the passive zone as the concealed bracing, which solves many problems in the design of the shallow foundation excavations in thick silty layers. In the process of the project implementation, the time history curves at the column top displacement and the surrounding settlement are presented through the real-time monitoring of the horizontal displacement of supporting column top and the surrounding ground settlement. The trend of deformation and settlement is consistent with the design, which proves the rationality of the design scheme. The smooth implementation of this project provides a feasible idea for the economical optimization of similar projects and solves the problem of poor economic efficiency caused by the previous excessive design of shallow small foundation excavations in the soft soil area.

Key words: Thick Soft Soil, SMW Method, Passive Zone Reinforcement, Concealed Bracing, Green Construction