LABORATORY TESTS FOR TEMPERATURE EFFECTS OF CLAYEY SOIL PERMEABILITY

Due to many reasons such as the global warming,urban heat island effect and the geological concerns of nuclear waste disposal,temperature effects on the engineering properties of the clayey soils have being paid more and more attention. This paper uses the falling head permeability test to measure the permeability of clayey soils directly at various temperatures from 5 to 45℃. The soil samples are made from Nanjing Xiashu soil and silt clay. The results show that the temperature has significant impact on the permeability of the soil specimens. Firstly,the permeability increases upon heating; secondly,as the dry density of the clayey soil increases,the variation of permeability with temperature decreases correspondingly； thirdly,the mixed soil shows greater permeability than either silt clay or Nanjing Xiashu soil,and the silt clays permeability is a bit higher than that of Nanjing Xiashu soil within the experimental temperature range from 5 to 45℃. Finally,the mechanism of temperature effects on the permeability of clayey soils is discussed in terms of the viscosity of water,the double layer and micromeso structure change with temperature.