Parametric Analysis of Stone Column Reinforcement for Settlement Reduction of Quay Structures: A Case Study in Northern Morocco

Driven by the strategic development of maritime infrastructure in Morocco and the expansion of port systems in the world, settlement control of quay structures founded on soft soils remains a critical geotechnical challenge affecting serviceability and long-term performance. In the context of one of the largest ongoing maritime projects in Northern Morocco, this study investigates the effect of stone column reinforcement on settlement reduction of caisson-supported quay structures. The present research introduces a comprehensive parametric framework integrating three key design variables: mesh arrangement (triangular, rectangular and hexagonal), column diameter (D), and spacing (d), the latter being widely investigated in recent research, within the analytical formulation of the Priebe method. A representative geotechnical model was developed based on in situ investigation data, including soil stratigraphy, mechanical properties, and applied loading conditions. Initial settlements were evaluated using both Elastic and Oedometric approaches, and subsequently improved through the computation of the settlement reduction factor (β) for multiple design scenarios. The results demonstrate that settlement reduction is governed by geometric parameters and spatial configuration. The triangular mesh arrangement provides the highest improvement efficiency. Increasing stone column diameter significantly enhances the reduction factor, while excessive spacing reduces column interaction and limits performance gains. These findings provide a scalable and cost-effective design approach for ground improvement in coastal regions, where port infrastructure is frequently constructed on soft soils under increasing operational demands.