Effectiveness of Cross-Walls in Reducing Wall Deflections in Deep Excavations

Three cross-walls were installed to brace the diaphragm walls prior to excavation for a cross-over tunnel of the Taipei Metro in front of the South Gate of the old Taipei City and has now been a National Heritage. The tunnel had the maximum excavation depth of 20.1 m. Three-dimensional finite element analyses have been performed to evaluate the effectiveness and the influence of the cross-walls in reducing the wall deflections. The nonlinear Hardening-Soil model has been adopted in the analyses. The results of the analyses indicate that the maximum wall deflections are much reduced as a result and the effectiveness of cross-walls is thus proved.