Abstract:

The main task of shield tunneling method at urban areas under centerline of existing roads is to evaluate the adverse influence and protecting effects of viaduct foundations on existing road. This paper uses two dimensional finite element program PLAXIS to analyze a case at Kaohsiung area, where the distance between the outline of the shield tunnel and the foundation piles ranges from 1.4 m to 3.0 m. Comparison is made between the analysis results and the monitoring results. The output reveals that the influence of the stratum loss rate is more significant than other parameters and that the monitoring data coincide with the analyses results. It is recommended that good back grouting should be executed to reduce the stratum loss rate so as to reduce the adverse influences.

Key words: micro pile, shield tunnel method, viaduct foundation protection