Investigation of the Consolidation Settlement Calculation of Bangkok Clay using the AJOP Function

Abstract

This article investigates the theoretical approaches for calculating non-linear one-dimensional consolidation settlement in both normally consolidated and overconsolidated clay. In this study, for normally consolidated clay, the effects of different equations are compared, including the traditional linear equation, a curved function, and the AJOP (Arc Joint via Optimum Parameters) equation, which combines a curved segment followed by a linear segment in a single formulation. For overconsolidated clay, the applicability of the AJOP equation is evaluated alongside a newly developed unloading-reloading equation and compared with the conventional linear method. The findings reveal that the linear function tends to overestimate settlement when the initial stress or depth is low, whereas the curved function overestimates settlement at greater depths or higher initial stress levels. However, the curved function exhibits lower error compared to the linear function. The AJOP approach effectively reduces errors across both shallow and deep layers. Additionally, for overconsolidated clay, the settlement predictions obtained from the conventional and newly proposed methods are found to be closely aligned. Therefore, the AJOP-based method proves to be an effective tool for accurately estimating the consolidation settlement of clayey soils.