ABSTRACT
The interaction between heat and soil is very common in geotechnical engineering, such as subterraneous storage of highly radioactive nuclear waste, directly buried high voltage cable engineering, subterraneous storage and transmission of thermal power, and road subgrade engineering, etc. The effect of atmospheric temperature on subgrade soil is not exhibited by thermal expansion/shrinkage phenomenon simply; instead, it is indirectly reflected in the form ofmoisture content change under temperature effect. The thermal expansion/shrinkage phenomenon caused by temperature fluctuation is not obvious. By now, a great deal of studies on the effect of temperature fluctuation on soil has been carried out, and rich payoffs have been obtained. Rose (1968) studied the pattern of moisture transfer under the action of temperature gradient, suction gradient, and gravity. Preece & Hitchcock (1970) simulated one-dimensional diffusion of heat andmoisture in soil by test. Baladi&Ayers (1981) simulated transient moisture and heat transfer in infinite porous media by heating with a point source. Mitchell et al. (1981) simulated the field situation of directly buried high voltage cables by outdoor cable backfill test. Ewen & Thomas (1989) designed an apparatus composed of a horizontal glass tube and a heating rod mounted in the glass tube to simulate the process of temperature effect. It is seen that above tests employed heating rods to heat the soil directly, which may cause vaporization ofmoisture content in the contact part between heating rod and soil, especially under high temperature condition. Utilizing appropriate test means to study the heat transfer pattern in soil is of far
reaching significance to further reveal the mechanism of action of moisture content on subgrade soil.
