Deformation Characteristics Analysis of Supporting Structure Caused by Deep Excavation of Large-Span Subway Parking Lot in Deep Silt Stratum

Abstract

With the rapid development of China’s economy and the continuous improvements in urban modernization, the high-rise buildings, subways, civil defense fortifications, underground substations, underground storage, and other projects have increased, and the subsequent foundation pit projects, especially deep foundation pit engineering, have grown as well. Concurrently, the technical challenges and construction risks faced by deep foundation pit engineering have increased, especially in the coastal soft soil areas along rivers, due to the extremely fragile and sensitive geological environment. For this purpose, the ABAQUS finite element simulation software was used for numerical simulation analysis to study the influencing factors and the deformation rate of the diaphragm wall and aimed at different failure mechanisms of instability of deep foundation pit projects in the Yitian Parking Lot of Shenzhen Metro Line 10. Moreover, preventive measures for the deformation of supporting structures were proposed. The results showed that: (1) In the engineering mechanical properties of marine soft soil, deformation of the diaphragm wall is sensitive to the changes in the e-lnp rebound curve slope $$ \upkappa $$ and Poisson’s ratio v; moreover, the maximum surface settlement behind the wall is sensitive to changes in the critical state parameter M and Poisson’s ratio v. (2) A mechanical analysis model for diaphragm wall was established. All the external conditions are regarded as generalized loads or foundations. Furthermore, the interaction between the diaphragm wall and the soil is considered, which is closer to the actual situation. (3) The elasto-viscoplastic model of soft soil by Borja was established, and the deformation rate formula of the diaphragm wall was proposed.