Abstract: The prefabricated recyclable support structure provides a new green support system with economic security, functional coordination and sustainable development for the development of underground space. The physical model test of the foundation pit of a pipe-jacking working well in Zhengzhou city is carried out based on the similarity theory. A three-dimensional fluid-solid coupling model that can differentiate the deformation difference between rigid and flexible components in the support system is established by using the ABAQUS software. The stress and deformation characteristics of support structure in the process of dewatering and excavation are analyzed. The influences of dewatering and excavation on the deformation characteristics of foundation pit are also studied. Results show that in the processes of dewatering and excavation, both the stress and deformation of the primary support structures are all less than those of the design values, while the steel panels are prone to local yield at the position connected with the waist beams. The increment mode of horizontal displacement of retaining pile varies greatly with the processes of dewatering and excavation. With the progress of the dewatering and excavation of the foundation pit, the deformation of the support structure is less affected by dewatering, and the main factor affecting the deformation of the support structure is gradually changing from foundation pit dewatering to foundation pit excavation. The influence of foundation pit dewatering on the surface settlement is greater than that of foundation pit excavation. The surface settlement increases rapidly during the first level of dewatering, with the maximum settlement increment accounting for 44.6%.

Key words: prefabricated recyclable support structure, foundation pit excavation, foundation pit dewatering, physical model test, finite element analysis