Analysis of consolidation settlement of normally consolidated soil by layering under 3D conditions

Abstract

This study analyzed the effects of conventional practice of calculating consolidation settlement of soft ground by dividing the ground into one or more layers. Based on a numerical analysis of the accuracy of the calculation and the settlement behavior resulting from layering, this study found that the existing settlement calculation method always underestimates settlement, and that the smaller the number of dividing layers, the smaller the calculated settlement is observed. In addition, when the ground is divided into an infinite number of layers, the settlement is 1.2 to 50 times larger than the case when the ground is considered as a single layer, and the difference grows larger at the lower ratio of an applied pressure to an effective stress (A0), the higher ratio of a layer thickness to a footing width (H/B), and the lower ratio of the length to width of a footing (L/B). The exact settlement can also be obtained under a single-layer condition, even when using the existing settlement calculation method, if the representative depth of calculation of the effective stress is set at a depth of approximately 10-38% from the top of the clay layer.