Two-dimensional parametric study of geosynthetic-reinforced column-supported embankments by coupled hydraulic and mechanical modeling

Geosynthetic-reinforced column-supported (GRCS) embankments have been increasingly constructed over soft soil. Current design methods were developed based on different assumptions and simplifications, which lead to great variations among them. Numerical studies have been conducted to improve the understanding of the GRCS embankment system. Most of the past numerical studies were limited to mechanical modeling only (i.e., not coupled with hydraulic modeling), which can be used to evaluate long-term or short-term behavior by using appropriate mechanical properties. However, the generation and dissipation of excess pore water pressure under GRCS embankments during and after construction make their behavior time-dependent. A two-dimensional (2D) parametric study based on coupled hydraulic and mechanical modeling was conducted to study the time-dependent behavior of GRCS embankments under various conditions. Special attention was paid to the influence of several key factors on the performance of the embankments indicated by maximum and differential settlements, tension in the geosynthetic, and degree of consolidation. The investigated key factors include modulus and permeability of the soft soil, modulus and spacing of columns, tensile stiffness of the geosynthetic, and average construction rate. The influence of these factors are compared and rated in terms of the degree of importance in this study.