Hydro-Mechanical Constraints and Deformations in Road Embankments Using Unsaturated Low-Swelling Soil

Abstract

In this paper, we present the results of a simulation of the evolution of stresses and deformations in a road embankment using unsaturated low-swelling soil under hydro-mechanical pressures, modeled with the finite element code Code_Bright. We assume that this embankment, which supports asphalt, follows the Barcelona Thermo-Elasto-Plastic model (BBM-TEP). This model describes the Thermo-Hydro-Mechanical (THM) behavior of unsaturated fine soils based on variations in net stress and suction. Through this simulation, the analysis focuses on the collapse of road structures, which is generally due to the poor quality of materials used but also to natural phenomena such as capillary rise and anthropogenic factors such as overloading. It was found that capillary rise leads to an increase in the degree of saturation by more than 50% at the edges of the structure and deformations of up to one centimeter when additional loads are applied to the embankment surface. The behavior of unsaturated soils is also highlighted, such as the decrease in void ratio with increasing effective stress or suction and the increase in suction with effective stress.