3D Numerical Analysis of Piled Raft Foundation on Soft Soil Improved by Stone Columns

• Published in: TRANSPORTATION INFRASTRUCTURE GEOTECHNOLOGY
• Main Authors: Jais, Ismacahyadi Bagus Mohamed; Rahman, Sharifah Nur Syafiqah Syed Abdul; Lat, Diana Che
• Format: Article
• Language: English
• Published: SPRINGERNATURE 2025
• Subjects: Engineering
• Online Access: https://www-webofscience-com.uitm.idm.oclc.org/wos/woscc/full-record/WOS:001406418700002
• ISSN: 2196-7202; 2196-7210
• DOI: 10.1007/s40515-025-00539-2

This study investigated the behavior of piled raft foundations in soft soil improved by stone columns of different lengths and diameters. Three-dimensional (3D) finite element analyses were conducted to evaluate the effects of area replacement ratio and slenderness ratio on settlement behavior under uniformly distributed vertical loads. In terms of settlement reduction, adding stone columns effectively reduced the total settlement of the piled raft system by 20.1 to 26.9%, thereby improving the raft-bearing capacity. Regarding foundation system behavior, the raft experienced maximum settlement at the middle of the raft, while piles at the side of the raft deformed laterally at the top of the pile, and the piles at the center of the raft settled vertically. Stone columns were observed to experience three modes of deformation: (1) lateral bulging; (2) short column penetrates clay and long column absorbs deformation along its length; and (3) slender column acts as laterally loaded pile. In terms of proposing optimization, settlement can be reduced by using a stone column of lower area replacement ratio (ARR) with a higher slenderness ratio (L/D).