Study on the Adsorption Characteristics of Loess Influenced by Temperature Effects

Loess, a typical unsaturated soil, is a Quaternary sedimentary deposit widely distributed across arid and semi-arid regions worldwide. In recent years, global climate change has led to significant temperature fluctuations in Northwest China, impacting loess properties and soil–water characteristic curves (SWCCs). This study investigated typical loess deposits in Mizhi County, Shaanxi Province, systematically analyzing their basic physical properties and microstructure. The SWCCs of the loess were measured at three temperature gradients (15 °C, 20 °C, and 25 °C) using the dynamic dew-point isotherm method to investigate the impact of temperature on SWCC hysteresis. The results showed that with increasing temperature, the SWCC exhibited increasing divergence. The magnitude of the water content change and the corresponding suction forces along the wetting and drying paths increased, leading to an enlargement of the hysteresis loop area. These findings indicate that temperature significantly affects the hysteresis behavior of loess, providing a certain basis and ideas for the study of the soil–water characteristic curves of unsaturated soils such as loess under the influence of temperature.