MODEL TEST STUDY ON STEAM DIFFUSION LAW OF UNSATURATED LOESS

The moisture content of loess have a significant influence on the strength of the soil. It changes with the cyclic change of moisture content, which leads to a series of diseases. In order to study the diffusion and migration law of water vapor and temperature in unsaturated loess, we analyze the water vapor and temperature diffusion migration in unsaturated remolded loess through the indoor filling model test. We inject the high temperature and high pressure water vapor into the remolded loess. The experimental results show that in unsaturated remolded loess, the range of water vapor diffusion is approximately ellipsoid. The water vapor diffusion rate decreases gradually along the radial direction. The vapor diffusion rate, diffusion range and humidification degree can increase with the vapor pressure increase. Vapor pressure accelerates water diffusion and also the temperature migration. The heating rate of soil is about 0.75 ℃ ·min^-1 when the pressure is 50 kPa and 1.12 ℃ ·min^-1 when the pressure is 200 kPa. The greater the soil particle hinders the water vapor diffusion when the density of the soil is more larger. The hindrance is more obvious and the larger the water content decreases with the increase of the radial diffusion distance of the water vapor.