Behavior of retaining wall during dewatering before soil excavation under layout of staggered wells

The dewatering conducted before soil excavation is an important stage in deep excavation. This dewatering construction is proved to be able to induce considerable deflection of retaining wall. However, how to control this type of deformation has not been proposed. A method called layout of staggered wells is proposed to control the dewatering-caused wall deformation. In this method, the uniformly-spaced and uniformly-buried layout of wells (i.e., the conventional layout of dewatering wells in practical engineering) is not advocated. It is recommended that (1) deeper wells should be employed near the retaining structures, and when the distance to the retaining structures increases, the wells depth should decrease gradually, and (2) smaller spacings of neighboring wells should adopted near the retaining structures, and when the distance to the retaining structures increases, the spacings of neighboring wells increase gradually. The numerical results show that the proposed method can lead to a smaller seepage flow velocity around the wall. Hence, the horizontal deformation of soil induced by seepage force will be relatively smaller, which eventually limit the deformation development of the retaining structures.