Hydro-Mechanical Interaction


Hydro-Mechanical Interaction in Permeable Pavement Structures in Partially Saturated Conditions

Logos of project participants   Schematic representation of roadway superstructures Copyright: © ISAC

Conventional pavements are designed to remain well sealed in order to avoid moisture penetration into their structure, preventing from damages. However, with the rapid expansion of sealed areas due to urban development and industrial activity, the natural water retention of soils experiences a significant decrease. To recover the natural hydrological cycle and diminish the urban flood risk, permeable pavements may be implemented, allowing the direct seeping of rainwater through the pavement surface. Therefore, during rain events, the water is able to infiltrate through the pavement structure and reach the subsoils, reducing the pressure in urban drainage and contributing to supply the natural cycle of water. However,their porous structure may induce moisture-related damages, a mechanism which is still not clear among the scientific knowledge. In fact, the hydro-mechanical interaction between pore-water and solid skeleton remains unknown upon traffic loads.

The aim of this research is to investigate the hydro-mechanical properties of fully permeable pavements using a porous polyurethane-bound (PU-bound) surface layer. Both surface and base layers will be studied by simulating several saturation and traffic conditions. Hydraulic and mechanical properties will be evaluated by building a pilot permeable pavement structure and embedding and instrumentation system, capable to quantify the hydro-mechanical characteristic of such solution. Based on the fundamental laboratory investigation, the project also aims to provide an improved hydro-mechanical model for the behavior of pavements under unsaturated condition in terms of vectors of pore-air pressure, pore-water pressure and soil matrix deformation. Based on the modified theoretical framework, the simulations will be carried out via a finite element approach and the results will be validated by comparing with field data. With the coupled hydro-mechanical model, the damage mechanism of porous pavement structures will be revealed.