Performance-based design optimization of embankments resting on soft soil improved with T-shaped and conventional DCM columns

This paper presents a parametric study of the optimization design for T-shaped deep cement mixing (TDM) and conventional deep cement mixing (DCM) columns improved soft soil for supporting embankments. The objective of the optimization was to find the best compromised solution for the cost effectiveness in conjunction with minimizing the serviceability limit state (SLS) requirements (i.e., settlements, differential settlements, and lateral movements) while maximizing the ultimate limit state (ULS) requirement (i.e., factor of safety against bending failure). A combination between a genetic algorithm and the response surface method was employed as an optimization approach for determining the optimal solution. The relations and interpretations between design column parameters and design requirements are presented and discussed through parametric studies. The optimization results indicate that the optimal TDM column can allow to permit a lower construction cost than the optimal DCM one.