Deformation Behavior of Retaining Walls in Deep Excavations in Suzhou Subway Line 1 of China

Data of wall deformation due to deep excavations of 23 stations in Suzhou subway line 1 was collected, and the deformation behavior of the three types of retaining walls (diaphragm wall, secant pile wall and soil mixing wall) was analyzed. The results show that the ratio of the maximum horizontal displacement of diaphragm wall to the excavation depth ranges from 0.11% to 0.33% with a mean value of 0.213%, and the ratio of the maximum horizontal displacement of secant pile wall and soil mixing wall to the excavation depth ranges from 0.23% to 0.40% with a mean value of 0.298%. The maximum horizontal displacement of the retaining wall occurs near the excavation bottom. The factors that influence the wall deformation were analyzed, including embedded depth ratio of the retaining wall, average vertical spacing between supports, ground improvement below the bottom of excavation, and the depth of the first level support.