Deformation Response of Soft Foundation Soils under Tall Embankments

Deformation Response of Soft Foundation Soils under Tall Embankments - A Numerical Analysis

Gizem Bozkurt, Merve / Fratta, Dante

The construction of tall embankments on soft soils requires staged construction, which leads to an increase in effective stress, reduction in void ratio, and gain in shear strength. Tall embankments are not fully constrained in lateral directions; hence, they contribute to the potential of global failure of the foundation soil and generation of lateral movements that may magnify vertical settlements of the embankments. This study systematically evaluates the relationship between lateral movements and the magnitude of vertical settlement on embankments using numerical analyses and analytical methods. PLAXIS, a finite element package, is used for modeling and analyzing deformation of soil embankments and foundations. Parametric studies were conducted to assess the contribution of lateral deflection to vertical settlement. The methods presented herein are validated using field data of a newly constructed interchange in Northeast Wisconsin. Results indicate that an increase in the effective stress due to staged construction leads to an increase in excess pore water pressure that highly depends on consolidation time and location of the soil under embankment. Also, the contribution of lateral displacements to vertical settlements is maximum for normally consolidated clays and decreases as the overconsolidation ratio increases, therefore the problem can be considered as a K_O- settlement condition for highly overconsolidated soils.