Abstract: In light of the issues on frequent destruction derived from slump and shallow landslide of loess slope after rainfall, the study mainly focuses on revealing internal moisture-heat change process of unsaturated loess slope under rainfall infiltration and sunshine evaporation. This research employed a laboratory loess slope model, regulated the rainfall-insolation cycle, and monitored the temperature, moisture and surface displacement. The results show that the depth affected by internal temperature and water infiltration of unsaturated loess slope is limited; in the range of 30~40 cm, under conditions of rainfall and sunshine. These show that, generally, the destruction depth of loess slope with slump and instability is limited, which mostly is a shallow slump. With the change of rainfall and sunlight, the slope surface displacement in the model occur a slight deformation on expansion or contraction.

Key words: unsaturated loess, model test, slope, temperature, volumetric water content