北京新机场"锅盖效应"一维现场试验

'Pot cover effect'in this paper refers to the phenomenon whereby moisture accumulates underneath an impervious cover. 'Pot cover effect' may lead to a high moisture rate in soil under covering and thus induce engineering disasters. At present, the main researching methods of 'Pot cover effect' are limited at case study, laboratory test and numerical simulation. However, there are few reports regarding on the field test of 'Pot cover effect'. This paper introduces a one-dimensional field test of 'Pot cover effect' in Beijing New Airport. Two contrasting conditions, with or without an impervious layer at the depth of 45cm, are tested. The test data from December 2016 to April 2017 are collected. The test results reveal that the 'Pot cover effect' appears in the test soil without the impervious layer. It is verified that 'Pot cover effect' is caused by water vapor migration in soil. The test data of the test soil with the impervious layer show that the impervious layer can effectively suppress 'Pot cover effect'.