Behavior of Bored Tunnels in Egypt Soft Clays

Abstract

The primary objective of this research study is to investigate the behavior of a typical bored tunnel crossing Suez Canal at the south of Port-Said City, referred to as Port-Said Tunnel (PST). The tunnel is constructed in a deep very soft to firm clay deposit lying in El-Tina Plain and is known as Port-Said Clay. The Port-Said Clay characterization is based on the results of recent research studies. The available information on the bored tunnel was limited to the method of tunneling which is TBM with slurry support and compensation grouting through the tail, geometric configuration and boring diameter. No field measurements were available for use in this research study. The interaction between PST and Port-Said Clay is investigated by numerical analysis. The finite difference-based program FLAC 7.0 is utilized in the analyses. The constitutive behavior of Port-Said Clay is described using the modified cam clay (MCC) model. Due to the absence of field measurements for the typical bored tunnel under investigation, verification of the numerical model results is carried out by simulating the behavior of a bored tunnel in similar ground conditions in eastern Canada (Thunder Bay Tunnel) using the same numerical method and the same constitutive model. The numerical analysis results are compared with the available field measurements.