|dc.description.abstract||Recently, Japanese engineers developed a new ground improvement method, which is called grid-wall ground improvement. The method adopts underground walls to constrain the dynamic shear deformation of soil during earthquake to prevent soil liquefaction. This research uses a two-dimensional explicit finite difference program, FLAC2D to analyze the constraint effect of shear deformation of soil by the underground walls. The design parameters are the spacing, the thickness, the rigidity of the underground walls, and the bearing layer.
The result shows that only when the spacing of underground walls is smaller than 5 m, the constraint effect of the shear deformation of soil becomes obvious. The thicker the underground walls, the higher the rigidity of underground walls, the more the constraint effect. In the case of underground walls without top slab, the shear deformation of soil in shallow depth constrained by the walls is greater than the shear deformation of soil in the free field. The reason is the large deformation created at the top of walls which causes surrounding shallow soil having larger shear deformation. In the case of walls with top slab, the shear deformations of shallow soil is more or less the same as the shallow soil in the free field. This is because the top slab constrains the large deformation at the top of walls during shaking. In all the conditions, the underground walls can constrain the dynamic shear deformation of soil very well when the bottom of underground walls are in the bearing layer. If build a construction on the underground walls, it can decrease the settlement and the tilt of the building obviously.||en_US|