Technical Study On Observational Method Applied To Superposed Dural Tunnel Of Shenzhen Metro

The fundamental characteristic of tunnel design is geological & environmental complexity and inadequate of basic information, the construction of tunnel works has great uncertainty and high risks. In home and aboard case history, it had mainly depended on the experience of technical staff concerned quite a long time; the development in areas of geo-techniques and measurement technique, database management technology and computer-aided design technology etc has pushed tunneling into "Observational Method (hereinafter referred to as OM) era".The OM is eminently well suited for tunneling. Tunnels are linear structures, allowing for modifications in design and construction during their excavation. It is inherently capable of solving uncertainties, hedging risks and establishing warning system against major failures or collapse, thus achieving the goal of security and economy.This paper takes design & implementation of construction measurement of superposed dual tunnel as its basis, investigating from measurement principles, data gathering & measurement design, data analysis and feedback with emphasis on data analysis and feedback. Based on the gathered data, especially displacement data, statistically analyzing and feed back according to various empirical methods, theoretical norm and FEM computation are conducted so as to grasp the rules of deformation and stress of ground and structure, assess the stability of ground and structure as well as determine reasonable support time and parameters, ultimately achieve safety without compromised safety. Finally, it concludes the feasibility and essentiality of various empirical methods, theoretical norm and FEM computation in OM as well as the achievements of this case works.