EXPERIMENTAL STUDY ON THE THERMAL CONSOLIDATION OF SATURATED CLAY UNDER CYCLIC HEATING AND COOLING

The thermal consolidation characteristics of saturated clay under cyclic heating and cooling are studied by laboratory tests. Test results show that the temperature rising ratio of specimens decreases with the increasing of temperature. However, the temperature dropping ratio is just contrary. Furthermore, the patterns of temperature variation of specimens during the period whether the processes of rising or cooling are independent of the cyclic number of thermal loading and confining pressure. An obvious pore pressure is generated by heating in undrained conditions. It should be pointed out that the pore pressure in the first number of cyclic thermal loading is much larger than that in the second number of cyclic thermal loading. On the other hand, a negative pore pressure is first induced by cooling in undrained conditions. Then, when the temperature is dropped to the required temperature value, the pore pressure begins to rise and subsequently becomes to be a positive pore pressure. Whether after the heating processes or after the cooling processes, a drainage effect of specimens is displayed generally in drained conditions. Furthermore, the volumetric strain induced by heating is much larger than that induced by cooling.