An experimental investigation of the pile-soil interface characteristics in cold region under varying exposure temperature and accumulated permanent deformation under freezing-thawing cycles

Abstract

The creep behavior of the frozen soil-structure interface as the research point in this paper subjected to mechanism theory principles of water-thermal coupling cycle was exhibited. There are mainly three situations, one is pile uplifting in the freezing heave period owing to frost heave force, then soil melt, and the pile would keep stable which the skin friction supported the pile at interface, three is both cases acting as stated above, the positive frozen cohesive is not enough to support the pile in frozen soil combined the negative friction at the same time. The frost heave with creep effect analysis was given the mainly concern. The emphasis of the frost heave phenomenon considering inner shear behavior under different geometric parameters in Freezing-Thawing cycle pointed that creep effect of the soil-pile interface played a domain role in the total deformation of interface due to common source of the settlement and uplift in cold regions. It reveals that the actual strain rate was sensitive at deeper soil layer by layer towards ground, according to the good agreement between the relaxation data and secondary creep conditions. The best fit regression was occurred in the period of approximate 65 th day to 200 th day accordingly. The strain mainly presents promoted when the temperature are below-2℃ in freezing transmission period, while it shows reduction trend with water content increase to ice-rich soil. It is taken for that with flow rate varying with stress conditions which exceed a yield stress level. And it shown the relationship of stress and strain at various depths with diminished lay-up character distribution. The numerical calculated result was shown that the high cohesion concentration zone be in the position of-2m depths of pile. And the mechanism model can be described by Kelvin-Voigt model, with validating by experimental simulation and published literature. Above all, it can be seen the temperature and moisture were the most significant effects for interface frost heave, which is indicated by the shear creep response analyzing. The combination of factors closely associated with the cohesion leading the pile continuously uplifting. The creep effect worked on the interface separated by three stage of primary creep stage, secondary creep stage and tertiary creep stage in frozen and thawing period by different cohesion force. So the characteristics of creep combined the Kelvin Voigt model was presented in this paper.