Contrastive Study on Permeability Characteristics of Angolan Red Sand and Chinese Malan Loess

The permeability coefficients of Luanda red sand in Angola is measured by laboratory variable head permeability test and double-ring water infiltration test. Based on the test data and references, the permeability characteristics of Angola red sand and Chinese Malan loess were compared and analyzed. The results show that the permeability coefficient of natural red sand in laboratory test is 1/8 of that in field test, and the permeability coefficient of compacted red sand in laboratory test is close to that in field test. The logarithm of the permeability coefficient of red sand is positively correlated with the void ratio, and increases linearly with the increase of void ratio. The permeability coefficient of red sand can be estimated according to the void ratio in engineering construction. The permeability coefficient of red sand in natural state is about 10 times that of Malan loess, and the field test results are greater than the laboratory test results. Both red sand and Malan loess have horizontal infiltration and vertical infiltration, but the infiltration distance of red sand is larger than Malan loess. The infiltration process of red sand is mainly unsaturated, while that of Malan loess is mainly saturated. The research results can provide reference for engineering construction in red sand area.