Assessing soil-water characteristic curves of sandy soils in Rakhine using the evaporation method with a simple device

The purpose of this study is to determine the Soil-Water Characteristic Curves (SWCCs) of silty sand and poorly-graded sand from Rakhine State, Myanmar. We used a simplified SWCC testing device with the evaporation method. This device enables simultaneous monitoring of soil water content and suction during both drying and wetting processes. We analyzed and compared the distributions of matric suction and gravimetric water content and fitted the SWCCs using appropriate models. Furthermore, we evaluated SWCC parameters, such as the air-entry values and fitted residual water contents, for the soil samples. During the drying process, the surrounding temperature had a significant influence on the experiment, resulting in fluctuations in temperature and water content over time. The novelty lies in validating its practical efficiency for sandy soils from Myanmar, for which no prior SWCC data exist, thereby contributing valuable regional reference data, including fitted SWCCs, and demonstrating its suitability for geotechnical applications in similar field conditions. The evaporation method using this device is efficient for sandy soils within its measurable suction range (0–90 kPa), reducing testing time while effectively capturing soil-water characteristics. However, there are limitations, including temperature fluctuations during the test and the tensiometer’s restricted readable limits. Continuous optimization of this method is necessary to assess soil-water characteristics accurately.