| On the basis of the existing researches about the fully coupled thermal field and moisture movement in unsarurated loess soils, this paper gives the finite element module of thermal field after consideration of various natural elements such as wind speed, radiation, evaporation, and meanwhile put forwards the finite element module of moisture movement on saturated-unsaturated loess soils. Furthermore, The paper also probes into the thermal and moisture transferring and coupled theory, and gives finite element module of fully coupled thermal field and moisture movement in unsarurated loess soils. Taking the unsarurated loess soil sample, the water content distribution of the soil with various density and moisture content is tested in various thermal gradients. The test data indicates that the water content distribution of the soil sample changes obviously after taking a thermal gradient on the soil. The water content in the soil with lower temperature is added, and with higher temperature is lowed. The water content gradient of the soil is related to the soil water content and density and temperature gradient. The more is the temperature gradient, and the less is the soil density, the more is the water content gradient. If the soil water content is gradually added from very little value, the value of water content gradient resulted from temperature gradient first is lower, then bigger and finally lower. Based on the test data, a linear regression equation about temperature and water content is got. After deciding the temperature and moisture distribution of the soil samples, the problem of coupled thermal and moisture is discussed, the temperature distributions show that the heat-conducting coefficient is related to the density and water content. The more is the density, the more is the heat-conducting coefficient .If the soil water content is gradually added from very little value, the heat-conducting coefficient first is lower, then bigger and finally lower.
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