Design of Protection Measures for Deep Excavation of A New Underground Station Closely Adjacent to Viaduct of MRT System in Operation

Due to limited land space in urban area, interchange MRT stations have to be constructed closely adjacent to existing system. Geotechnical design of new station has to ensure the safe operation of existing line. This paper presents a new underground MRT station located within 1 m of the foundation of viaduct of MRT line in operation with ridership more than 200,000 persons per day. Deformations inducted by deep excavation have to be controlled Deformations induced by deep excavation have to be controlled carefully to meet the rigorous limit values set up by Regulation of Building Restrictions along MRT Facilities. Sophisticated 2D/3D finite element (hereafter FEM) analyses have been performed to simulate the sequence of diaphragm wall constructions and Bottom-up deep excavation with pre-stress strut system.