Pot cover effect and its prevention: An experimental study in the field

Abstract Pot cover effect in this paper refers to the phenomenon that soil moisture accumulates underneath an impervious cover at ground surface, and may lead to engineering problems in cold region. This paper introduces a field test on the pot cover effect in Beijing New Airport. The field test consists of two cases: two impervious covers were set at ground surface with natural ground (case #1) and with an impervious layer placed at a depth of 44 cm (case #2). The soil moisture and temperature were measured and recorded from December 2015 to December 2018. The test results reveal that pot cover effect can be observed in the soil without the impervious layer (case #1) but can be prevented by placing an impervious layer at the depth slightly below the maximum freezing (such as case #2). The test results confirmed that the impervious layer set at suitable depth can effectively eliminate pot cover effect.