Stability of Temporary Railway Trestle Crossing Deep Excavation

Ningbo high speed rail station located in the Southeast coastal area of china is one of the newest comprehensive transportation hub that integrates railway station, subway station and other transfer transportation tool. The foundation pit of the project stretches an area of 265m×124m and a depth of 24m. Soil in this area has unfavorable characteristics such as compressibility, sensitivity. A series of precautionary measures were adopted in design and construction which facilitated the unprecedented in china the non-phased massive excavation and building of the station house by temporarily adding a trestle spanning over the foundation pit. This creative technique not only saved nearly 1/3 of the construction period compared to the traditional way but also the project cost. In this article the impact on deformation, dynamic characteristic and the vehicle-bridge coupling vibration of the temporary trestle from soil upheaval due to unloading during excavation is studied.