Investigation of in situ soil-atmosphere interaction with a hydro-thermal simulation approach: application to an instrumented site

Abstract

In this article, a simplified soil-atmosphere interaction analysis is proposed by using a simple mass/water balance equation and a thermal based energy balance approach which gives the infiltration rate and the soil surface temperature respectively. The deduced surface temperature is primarily validated by comparison with field measurements (Héricourt site) and secondly by comparing the derived net solar irradiance to seven net irradiance models. Finally, a hydro-thermal simulation approach established by relating the variations of the soil water content to the soil thermal conductivity, is applied to the Roaillan site, which was monitored since 2011 to investigate the hydro-thermal changes of the soil due to environmental stresses in the vicinity of the foundation of a damaged building. The simulation results provide the necessary data to determine the affected depth of the soil due to climatic conditions. Results show that the first layer (< 1.5 m depth) is mainly affected by climatic conditions in which the variations of water content and suction are less than those of temperature. Furthermore, the soil settlements are also compared to the extensometer measurements at three different depths. Although some differences exist but globally the proposed approach is able to consider the soil-atmosphere interaction in its framework.

Keywords:

• Soil-atmosphere interaction
• hydro-thermal simulation
• monitored site
• climatic data
• soil suction

Acknowledgments

The authors would like to acknowledge DETERMINANT Group for its financial support. The authors would also like to thank the IFSTTAR (The French institute of science and technology for transport, spatial planning, development and networks), the CEREMA (Center for Studies and Expertise on Risks, the Environment, Mobility and Development), the BRGM (French Geological Survey), the University of Bordeaux (I2M Laboratory) and Alain Franck Béchade for their support on collecting in situ field data and their collaboration in this research project.

Disclosure statement

The authors declare that they have no conflict of interests.

Additional information

Funding

This research was funded and supported by the French National Agency of Technological Research (ANRT) as an industrial based R&D program (CIFRE N° 2015/1157) on drought and climate change effect on natural clayey soils interaction with constructions.