Analytical Study On One-dimensional Thermal Consolidation Theory Of Saturated Soil

Thermal consolidation theory of saturated soil is one of the most important research topics in the field of geotechnical engineering. It bears the important significance in most engineering projects such as heat energy storage, geothermal energy exploration, nuclear waste disposal. To complement the research of thermal consolidation theory of saturated soil, this dissertation gives a systematically study on the analytical theory of one-dimensional thermal consolidation of saturated soil. The main original work are made as follows:(1) On the basis of reviewing the references about soil properties with temperature and thermal consolidation of soil, thermo-hydro-mechanical governing equations are developed by using traditional consolidation theory for saturated soil, thermoelasticity, seepage theory and heat conduction theory, three-dimensional thermal consolidation equations for saturated soil are constructed, and it can be reduced to the one for one-dimensional thermal consolidation problem.(2) For the simplist thermal consolidation problem with instantaneous constant surface temperature and uniform initial pore-pressure, analytical solutions of excess pore-water pressure and temperature are derived and compared in detail, respectively. The results show that the thermo-mechanical coupling item in the thermal consolidation equation can be ignored. Based on the above mentioned and considering different conditions, analytical solutions for one-dimensional thermal consolidation problems are derived, respectively. The all traditional one-dimensional consolidation theory without considering temperature so far available are the special case of these solutions.(3) By using the analytical solutions given herein, a variety of consolidation curves are prepared and the influence of various factors on the dissipation of pore water pressure and the development of settlement and degree of consolidation are dicussed. It has been shown that the main factors affecting thermal consolidation behaviour are: dimensionless parameter R (it indicates temperature increase.), the ratio of heat diffusion coefficient and consolidation coefficient F (it indicates velocity of heat conduction and consolidation.), loading time-factor T_V0 (it indicates loading time), half-period time-factor T_vc (it indicates period of temperature change), etc. Generally, in thermal consolidation, compared with traditional consolidation without temperature effect, excess pore-water pressure dissipates more quickly; settlement decreases; comparing with Terzaghi's one-dimensional consolidation theory, the influence of temperature on excess pore water pressure is smaller than on settlement; two consolidation degrees defined by stress and strain are of great difference in value.It is in this dissertation that the theoretical solutions for one-dimensional thermal consolidation problem is firstly derived under complicated conditions such as non-uniform initial pore-pressure, time-dependent loading, cycly changing surface temperature. This not only makes a good foundation for future study on the thermal consolidation of saturated soil, but also makes the analytical consolidation theory of saturated soil more perfect.