关键词: 桩?土接触面, 温控, 热力耦合, 三轴试验

Abstract: In order to study the influence of temperature on the mechanical properties of pile-soil interface, a setup of temperature-controlled pile-soil interface triaxial shear test system was developed. The new instrument improves the internal construction of the pressure chamber based on the conventional triaxial shearing instrument. A special structure named pile-soil interface was built in the soil sample and two independent temperature control systems were established for pile and soil, respectively. As a result, the mechanical characteristics of the pile-soil interface under non-isothermal conditions can be tested. A series of triaxial tests were carried out on the thermal-mechanical coupling characteristics of pile-soil interface of sand under different shear conditions and temperature levels. The temperature control accuracy of pile and soil, the shear stress of pile-soil interface, the pore water pressure variation under undrained conditions, and the volume change under drainage conditions were measured. The above results preliminarily verify the accuracy and reliability of the new temperature-controlled pile-soil interface shear test system. The new system has a simple structure and is easy to disassemble. It is also suitable for both temperature-controlled pile-soil interface shear test and conventional (temperature-controlled) triaxial shear test of soil samples. The relevant research results can provide technical support for understanding the thermal-mechanical coupling mechanism and constitutive modelling of the pile-soil interface.

Key words: pile-soil interface, temperature control, thermal-mechanical coupling, triaxial shear test