Analysis of road settlement on soft soil using 3D finite element method: A case study of the Amata Smart City construction project, Chonburi phase 2

The research explores the settlement patterns of road structures built on soft soil at the Amata Smart City Chonburi Phase 2 through evaluating the performance of soil cement column (SCC) support as a ground stabilizing strategy. Soft clay layers extending from 10 to 14 meters deep make up the project site and create substantial difficulties for bearing capacity and long-term subsurface movement. Although the effectiveness of SCC has been widely studied, limited research has addressed the feasibility of constructing roads without SCC by enhancing the strength of native soft soils. This study aims to fill this gap by evaluating alternative soil improvement techniques. A three-dimensional finite element method (3D-FEM) was analyzed to forecast settlements in two conditions involving road structures with or without SCC support. Predicted settlements received evaluations in construction time and the following 30-year operational span. The existing soil strength was evaluated through a parametric analysis to determine whether strengthening the soil would be a suitable alternative to SCC. Without SCC in road construction, maximum settlements amounted to five times higher than those built with it, specifically in the road center area. An Elastic Modulus of 600 MPa proved to be the most effective strength improvement of the original soil, resulting in a 12.28% reduction in differential settlement and a slight 1.75% reduction in total settlement. Applying suitable soil improvement methods allows road construction on soft soil to remain possible by omitting SCC procedures. SCC remains the most effective method for settlement control; however, road construction without SCC is also feasible when the soft soil subgrade is sufficiently improved. Research findings create knowledge that helps developers achieve better road designs, which balance performance quality and economical construction expenses on soft clay-dominated sites.