Parametric analysis of failure modes and stability of muti-level retaining structure in deep excavations

The multi-level retaining methods such as two-level single-row retaining piles or two-level single-row retaining piles and gravity retaining wall are applied in some large area deep foundation excavation projects. By using the finite element method, the failure modes and stability of multi-level retaining structure composed of one level of double-row piles and the other level of single-row are studied. Parametric study is performed to further analyze the effects of the length of single-row piles, distance between the two-level retaining piles and depth of the two levels on the stability of multi-level retaining structure. The results show that the length of single-row retaining pile can produce significant effect on the overturning stability when the length is longer than a certain length. Only when the distance of the two-level retaining piles is small compared to the excavation depth, it can have a remarkable effect on the overturning stability. The effect of ratio of the depth of the two-level retaining piles on the overturning stability is related to their horizontal distance.