Abstract: This paper presents a case history of the impact of a large deep excavation in Suzhou soft soils on the adjacent operational tunnels. The remediation measures are optimized in both design and construction. The soil parameters used in the analytical model were determined by the back analysis and the calibrated parameters were used in the performance of the operational tunnel during the entire deep excavation process. The numerical analysis results indicate that, the remediation measures used in the construction is effective and the impact of the deep excavation on the adjacent operational tunnel is acceptable.

Key words: Soft Soils, Large Deep Excavation, Tunnels, Finite Element Analysis