Laboratory Test On Thermal Properties Of Saturated Red Clay Under Temperature And Ambient Pressure

The effect of temperature on the properties of saturated clay is a popular research topic in the field of geotechnical engineering in recent years. It has practical value in energy storage, geothermal resources development, heating pipe design, nuclear waste disposal, soft reinforcement and other important areas. However, domestic researches are still rare in this area, and there are no targeted and systematic researches.This thesis utilize laboratory tests to study the thermal properties of saturated red clay under temperature and ambient pressure. The thermal consolidation test device including temperature control system developing, surrounding pressure systems, back-pressure control system and residual pore water pressure measurement system. Test scheme design drainage test and un-drainage test in two groups, the temperature ranges from20℃to80℃, and ambient pressure includes50kPa,100kPa,150kPa,200kPa. Based on results of this paper, the thesis has analysed the evolution of the temperature, pore pressure, and volumetric strain. Explained the residual pore water pressure and volume strain evolution law consolidation through the mechanism of thermal characteristics.Text results show that, Temperature change rate unrelated to the change of consolidation pressure, The temperature rising ratio of specimens decreases with the increases of temperature, however, the temperature dropping ratio of specimens decreases with the increases of temperature. For various confining pressures, the evolution patterns of whether pore pressure or volumetric strain is similar. In the process of temperature rising, the pore pressure increases continually with elapsed time, when the temperature reaches to a peak temperature, and the pore pressure also reaches to a peak pore pressure, similarly, in the process of temperature dropping, the pore pressure decreases continually with elapsed time, when the temperature decreases to a minimum temperature, and the pore pressure also decreases to a minimum pore pressure. This peak pore pressure increases as the confining pressure increases, but the normalized pore pressure decreases as the confining pressure increases. Higher temperature increases the variable quantity of both pore pressure and the consolidation volumetric strain. Besides, the consolidation volumetric strain by heating is greater than the volumetric strain by cooling, the specimen totally takes on a shrinkage effect after a complete process of heating and cooling.