Comparative research on the mechanical behaviour of underground parking constructed by Top-down and Semi-Top-down method: A case study of Tran Hung Dao underground parking (Hanoi)

Hanoi (Vietnam) has approximately 8.5 million inhabitants and suffers from severe traffic infrastructure insufficiency. The parking spaces in the city are lacking and have become one of the leading causes of traffic congestion. Underground parking facilities could be a solution. The Top-down, Bottom-up, and Semi-Top-down methods have been applied worldwide to construct shallow underground structures in soft soil. Comparative studies are needed to clarify their impacts on underground structures during construction. This paper presented the research on a shallow underground structure constructed by the Top-down and Semi-Top-down methods using numerical modelling. A model of 4-floor underground parking at the Tran Hung Dao station (Hanoi) was built, and the FEM analysis was realised. The behaviour of the parking structure, the diaphragm walls and the surrounding ground was investigated. The impact of the soil’s bulk modulus and the wall’s stiffness on the model’s responses was also studied. The obtained results show the clear influence of soil and the construction procedure on the behaviour of the numerical model. The research was hoped to enrich the knowledge on the construction of shallow social infrastructures in soft soil.