Characteristics of deformation of retaining wall due to deep excavation in Nanjing

Based on a linear foundation pit in Jiangbei, Region of Nanjing, a database of 35 case histories was collected. The characteristics of lateral displacement in Nanjing due to deep excavation are studied systematically. The research shows that the maximum lateral displacement increases with the excavation depth, which ranges from 0.05%H_e to 0.69%H_e, with an average value of 0.24%H_e. The maximum lateral wall displacements along depth occur within the range from H_e-8 to H_e+2 and most are above the excavation surface. The effects of time-space characteristics are found remarkable in lateral displacement of excavation in Nanjing. Hence, the time of exposure of the pit bottom should be as short as possible in construction. The SMW engineering method is relatively weaker in restraining lateral displacement than diaphragm wall and bored pile wall. In addition, the insertion ratio and length-width ratio can both affect the lateral displacement.