Laboratory Tests On Overconsolidation Effect Of Saturated Silty Clay Under Thermal Loading

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 good application backgrounds in energy storage, geothermal resources development, nuclear waste disposal, heating pipe design, soft reinforcement and other engineering fields. Currently, there is a certain degree of researches on the thermal consolidation problem, but not related to the consolidation properties of over-consolidated soils at a temperature loads and equivalent over-consolidation ratio caused by temperature loads acting on soil samples.Based on the studies of thermal characteristics of normal consolidated silty clay this paper has a further laboratory test on the over-consolidated silty clay by using thermal consolidation experiment, the main contents and innovations are as follows:(1)Under the condition of initial temperature (25℃) determined the dissipation of pore water pressure, excretion of the soil pore water and the evolution of volume strain of saturated silty clay during consolidation.Ambient pressure is set to50kPa, lOOkPa,150kPa,200kPa.(2)After the initial consolidation, experiment the soil samples with heating and cooling cycle test. Heating and cooling under the undrained conditions, temperature class are25℃-75℃and75℃-25℃,drainage after the temperature stabilized.The pores water pressure and evolution of solidification volume strain of the saturated silty clay was measured over the temperature cycle.(3) Under the initial temperature conditions, complete the initial consolidation when the ambient pressure is brought to the specified pressure. Then unload to the designated ambient pressure to complete the consolidation process of absorption choosing the over consolidation ratio2,3,4respectively.Tested the over-consolidated soil samples with heating and cooling cycle experiment In accordance with the above-mentioned temperature levels and the test content in (2) andmeasuredthe dissipation of the sample pore water pressure and the evolution of consolidation volume strain in the entire consolidation process.Based on the test results of this paper, by usingthe professional drawing softwarefitting, revealed theevolution of pore water pressure and the consolidation deformation of saturated silty clay over the temperature cycle process, and explained the evolution of pore water pressure and volumetric strain consolidation by the study of thermal characteristicsmechanism. Comparedwith different soil’s relevant datasof over-consolidation ratio, analyzed the over consolidation effects which was caused bytemperature and ambient pressure acting on the soil.then obtained theequivalent over-consolidation ratio with the cyclic temperature loads acting on soil samples. The results of the papers has laid a good foundation in the depth study of saturated soil’s thermal consolidation problem, and also enriched and improved the thermal consolidationproblems of saturated soil.