CONSOLIDATION TESTS OF HOLLOW CYLINDRICAL SATURATED SILTY CLAY SUBJECTED TO DIFFERENT HEATING-COOLING PATHS

Laboratory tests were conducted to investigate the thermal consolidation behavior of saturated silty clay soils using an axial thermal consolidation test apparatus suitable for saturated hollow cylindrical specimens. Using this apparatus, thermal loadings can be applied on both the inner and outer surfaces of specimens. The temperature paths include isothermal (inner and outer boundaries) single-stage and multistage heating-cooling processes and a non-isothermal (inner and outer boundaries) multistage heating-cooling process. The temperature ranges from 25℃ to 75℃, and the confining pressures are 50 kPa, 100 kPa, 150 kPa and 200 kPa. The evolution of the normalized pore water pressure and consolidation volumetric strain of specimens under different temperature paths and confining pressures are studied. Also the test results under different temperature paths are compared. The results show that the peak normalized pore water pressure (absolute value) induced by heating or cooling decreases as the confining pressure increases under the same temperature path. The consolidation volumetric strain is not a monotonic function of the confining pressure. Both the normalized pore water pressure (absolute value) and consolidation volumetric strain increase with the increase of heating or cooling magnitude under the same confining pressure. Heating or cooling to the same temperature by different temperature paths, the consolidation volumetric strain increases with the increase of temperature grades. The volumetric strain of isothermal multistage process is larger than that of non-isothermal multistage process under the same temperature grades.