Rainfall infiltration laws of compacted loess based on laboratory model tests

Based on the high loess-filled embankment projects in north western regions of China, the model test apparatus is developed to investigate the water migration of compacted loess under different rainfall infiltrations. An electrical resistivity model versus saturation degree (named Archie model) and a matric suction model versus saturation degree (called Fredlund-Xing model) are established, and then the power exponent prediction formula for electrical resistivity versus matric suction is also obtained. The evolution laws of infiltration ratio, saturation degree and electrical resistivity of compacted loess with time and depth under different types of rainfall and compaction degrees are revealed through a large amount of laboratory experiments. The results show that: (1) The rainfall infiltration features of compacted loess are very different. The infiltration line exhibits “Y” shape under light rain (the maximal infiltration depth H_max is equal to 0.20~0.35 m ), it appears to be “D” shape under heavy rain (H_max=0.20~0.35 m ), and it is inverted “V” shaped under intense fall (H_max>0.8 m). (2) There is a positive correlation between the infiltration ratio and the rain capacity, negatively correlated with soil depth and compaction degree. (3) The electrical resistivity method for soils can provide a new way for exploring in depth the long-term deformation mechanism and stability prediction or disaster prevention of high loess-filled embankments.