A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Civil Engineering

Thesis (M.Eng.) - Asian Institute of Technology, 1999

This research reviewed geotechnical aspects of underground works related to tunnelling and station construction of the Initial System MRT Project. Properties of subsoil through the tunnel alignment were summarized. Top-down method is performed in station construction. Station walls used diaphragm wall to support the surrounding soils. In tunnel works, eight EPB shields are adopted for excavation of the running tunnels. Tunnel lining consists of five and six regular precast concrete segments. The design method of segmental lining is of the Muir Wood (1975). Consolidation of the clay layer causes differential settlement of the underground structures founded on different foundation depths. The settlement prediction methods are based on the regression of land subsidence data and the consolidation compression/swelling characteristics of the clays. This research summarizes the results of differential settlement prediction that is expected between tunnel connections with other structures founded at a shallower or deeper depth. The evaluation of protection requirement followed damage classification given by Burland ( 1997) and Boscadin and Cording (1989). Pile foundations of canal bridge and overpass bridge obstructing the routes of bored tunnels, are underpinned with new piles. Ground treatment utilized in construction mainly consists of jet grouting in order to control the problems of soft ground.