Behaviour of weak soils reinforced with soil cement columns formed by the deep mixing method: Rigid and flexible footings

This paper presents a comparison of the failure behaviour of the Deep Mixing (DM) method under models of rigid and flexible foundations. A series of physical model tests at 1 g were performed in this study consisting of unreinforced and fully and partially penetrated soil–cement columns. For the improvement case, the columns of 23.5 mm diameter and lengths of 200 and 100 mm were installed in the ground model with an improvement area ratio, ap, of 26.0%. The failure mechanism was measured using close range photogrammetry and Particle Image Velocimetry (PIV). For verification, the bearing capacity performance and failure mechanisms were then compared with the Ultimate Limit State numerical analysis and the existing analytical solution proposed by Boussida. The results show a good agreement between the bearing capacity value obtained from the experiment and the numerical software.