3D Numerical Analyses for Optimization of Deep-Mixing Columns Combined by Raft Foundations

Abstract

In some cases, because of weak soil, the raft cannot provide sufficient bearing capacity. In these conditions, piles could be applied to enhance the bearing capacity and to reduce the settlements. In this regard, the deep-mixing method is one of the practical ground treatment methods. In this research, the raft foundation modeling combined with deep-mixing columns is performed using FLAC3D with the mixing parameters obtained using experimental uniaxial and triaxial tests. Several parameters such as the effective length, diameter, and distance of the columns and the optimum area ratio of the column group to the raft are investigated in the Firouzkouh loose sand. Then, column group optimization, including length and arrangement, is investigated. Finally, a comparison between using concrete piles and deep-mixing columns in raft foundations is performed.