Numerical Modeling of Water Transfer in Geomaterials: Application to a Concrete Tunnel Subjected to Both Drying and Liquid Overpressure

Abstract

Concrete structures can go through cycles of drying and saturation during their lifetime. In special cases, such as tunnels, dams, and piles, this phenomenon may occur frequently. Drying and saturation cycles should be considered because they adversely affect the short-term and long-term behavior of the structure. In this paper, a water transfer model is proposed to predict the moisture migration and water content field within the studied porous material. The switching between saturated and unsaturated states is done continuously, without resorting to a classical three state variables model, but using liquid pressure as a single state variable in the governing water transport equation. First, the hydric transfer model is presented. The underground structure subjected to drying and resaturation is then simulated in order to demonstrate the capacity and performance of the hydric model to consider simultaneously negative and positive liquid water pressure, which was not previously the case, for instance, in the classical Richards formulation. This example demonstrates the potential of the model to describe water transfer by smoothly transitioning from a drying condition to a saturated condition.