Description of a field test involving cracking in a drying soil

Abstract

The analysis of cracking in desiccating soils is a research topic that can be addressed by using concepts of Unsaturated Soil Mechanics. In this context, the use of physical models constitutes a promising tool to understand the mechanisms involved in this problem. In fact, previous works by the authors included the use of a laboratory environmental chamber controlling temperature and relative humidity. This paper, however, describes a field experiment consisting of a large container (3 m by 3 m and 0.5 m height) with a soil mass undergoing desiccation in an open environment near Barcelona. The container is continuously weighed to monitor the water loss evolution (or water uptake in case of rain). Basic soil variables are monitored as well: suction, water content, temperature and heat flux at different points inside the soil mass. Environmental variables, including temperature, relative humidity and wind speed close to the soil surface are also recorded. The test started early in January 2015 and the paper presents the preliminary results corresponding to the first few months. Due to the weather regime, the soil has undergone desiccation and some single rainy events. Crack patterns change dramatically when applying suction cycles to the soil.