Influences of 3D Effects, Wall Deflection Process and Wall Deflection Mode in Retaining Wall Problems

Abstract

Two-dimensional (2D) and three-dimensional (3D) model tests and the corresponding elastoplasticˆnite element analyses were carried out to investigate the in‰uences of 3D eŠects, wall de‰ection process and wall de‰ection mode on the earth pressures and the ground movements in retaining wall problems. Aluminum rod mass were used in 2D model tests, and alumina balls were used in 3D model tests. The stress-strain behavior of these materials is similar to that of dense sands with positive dilatancy. In theˆnite element analyses, a recently developed elastoplastic constitutive model, named subloading tij model, were used. This model can describe typical stress deformation and strength characteristics of soils such as the in‰uence of intermediate principal stress, the stress path dependency of plastic ‰ow and the in‰uence of density and/or conˆning pressure properly. The test results show that the earth pressures on the retaining wall in 3D condition are much smaller than those in 2D condition, and these distributions of earth pressure are more in‰uenced by the wall de‰ection process than by the wall de‰ection mode. Observed surface settlements at the backˆll just behind the wall in 3D condition are larger than those in 2D condition, but 3D surface settlements occur more locally. These 2D and 3D surface settlements are in‰uenced by the wall de‰ection process more than the wall de‰ection mode. However, at the same wall de‰ection process and the same wall de‰ection mode, there is not much diŠerence in the shapes of the earth pressure distributions and the surface settlement troughs between 2D and 3D conditions. These diŠerences and similarities of the earth pressures and the surface settlements are simulated not only qualitatively but also quantitatively in the analyses using the above constitutive model.

Model experiment and numerical analysis of horizontal subgrade reactions acting on flexible walls

“…The shear deformation δs was calculated from Equation (2) using the shear strain for each element and the height δH of each element. The ratio y' was calculated using Equation (3).…”

“…In this model, the subgrade reaction at a given depth is assumed to be determined only by the depth and displacement of the pile. However, the behavior of the subgrade reaction acting on a wall is known to vary with its deformation mode [3,4].…”