Large test to study the role of soil-air interaction in soil cracking

Soil surfaces in contact with the atmosphere are interfaces where different processes play an important role in triggering the formation of cracks due to desiccation. Empirical evidence shows that variables such as solar radiation, wind speed or relative humidity have an impact on the amount of soil water evaporation. To study this subject, a new large-scale test facility has been built in the field, consisting of a 3×3×0.5 m (4.5 m3) container filled with silty clay soil. There are internal sensors embedded in the specimen, and external sensors to collect measurements from natural conditions. The field experiment had duration of one year including all seasons. The specimen was continuously monitored with a digital camera, recording automatically images of the ground surface that were later used to analyze the crack pattern evolution using image analysis techniques. This paper presents some results from collected data in natural conditions including soil and air variables that will contribute to the understanding of crack formation and propagation in soils under changes of environmental conditions. The analysis of the results provides insight on the boundary effects in the cracking process and the role that the soil-air interaction plays in this process.