Analysis and Design of a Complex Underground Structure with Economic Comparison of Top-Down and Diaphragm Wall Construction Methods

Abstract

Analysis and design of an underground structure often brings with it, challenging technical issues. This study deals with the design of a subway station located in Tabriz city of Iran. Large dimensions of structure and relatively high level of underground water table and proximity of the project to the residential zone require the careful and precise analysis and design of soil–structure interaction. This study aims at comparing two top-down construction methods. In one case, the structure is comprised of steel frame with concrete diaphragm wall which is built from top to bottom story by story (top-down method). For the other one, the structure is comprised of reinforced concrete members and diaphragm walls are completely cast at the first stage of construction (diaphragm wall method) and then the structure is built from top to the bottom. To this aim, the soil–structure interaction is modeled by 3-D Abaqus and 2-D Plaxis models. A 3-D SAP model is also used to analyze and design the structure. The results indicate that the diaphragm wall method is superior to the top-down method in terms of economy and practical aspects.