Because of global climate change, drought occurs in increasing intensity and frequency across the world. Drought-induced evaporation can reduce soil water content and cause progressive desiccation cracking, which is responsible for various geotechnical and geo-environmental problems. This study aims to develop an ERM with a high spatial resolution and study the ERM performance in the characterization of soil water content dynamics from a quantitative point of view in small-scale evaporation tests, in order to support the future study of desiccation cracking in field investigations. An environmental chamber filled with initially saturated sand was designed for the evaporation test. As the chamber was subjected to drying, the evolutions of soil electrical resistance and water content at different depths were monitored continuously by the installed sixty electrodes and six time domain reflectometers (TDR) sensors, respectively. Experimental results indicate the good correlation between the measured soil electrical resistance and the water content. As evaporation continues, soil electrical resistance increases exponentially with decreasing water content. The variations of soil electrical resistance present an evidentially delayed effect along with the depth. A calibration relationship between the recorded soil electrical resistance by ERM and the water content measured by the oven drying method was established. Afterwards, the variations of soil water content at different depths were estimated based on the developed calibration relationship and compared with the TDR results. Besides, a numerical approach combining a soil-atmosphere interaction model and a coupled hydro-thermal model was employed to study the evaporation-induced variations of soil water content. The estimated soil water contents by ERM were further compared with the results obtained using the numerical method. The evaporation process with the movement of the evaporation front in the studied soil sample was also discussed in depth. This study presents that the developed ERM is effective to record soil moisture dynamics, especially in the near-surface zone, in small-scale evaporation tests. It also provides insights on the potential of ERM in field applications to characterize soil hydraulic responses to drought climate.

由于全球气候变化，干旱在世界范围内的强度和频率都在增加。干旱引起的蒸发会降低土壤中的水分含量，并导致逐渐发生的干燥开裂，这是造成各种岩土和地球环境问题的原因。这项研究旨在开发一种具有高空间分辨率的ERM，并在小规模蒸发测试中从定量的角度研究ERM在表征土壤水分动力学方面的性能，以支持将来在田间进行干燥裂纹研究。调查。设计一个装有最初饱和沙子的环境室进行蒸发测试。当腔室干燥后，分别通过安装的六十个电极和六个时域反射计（TDR）传感器连续监测不同深度的土壤电阻和水含量的变化。实验结果表明，测得的土壤电阻与含水量之间具有良好的相关性。随着蒸发的继续，土壤电阻随着水含量的降低呈指数增加。土壤电阻的变化随着深度的增加而表现出明显的延迟效应。建立了通过ERM记录的土壤电阻与通过烤箱干燥法测量的水含量之间的校准关系。之后，根据建立的标定关系估算不同深度土壤水分含量的变化，并与TDR结果进行比较。此外，还采用了一种结合土壤-大气相互作用模型和耦合水热模型的数值方法来研究蒸发引起的土壤含水量变化。将通过ERM估算的土壤含水量进一步与使用数值方法获得的结果进行比较。还深入讨论了在所研究的土壤样品中随着蒸发前沿的移动而产生的蒸发过程。这项研究表明，开发的ERM在小规模蒸发试验中可有效记录土壤水分动力学，尤其是在近地表区域。