Experimental Study On Tangential Frost-heave Forces Of Frozen Soil/Foundation In Cold Regions

In this paper, we set freezing soil and structure interaction as engineering background and abstract permafrost-permafrost and frozen soil-structure heaving shear specimens tests. We select two kinds of frost sensitive soil and present a systematical research on the temperature, frost heave, frozen heaving force, additional water amount of the soil samples under different constraint conditions of frost and water content dynamic of samples of different heights after tests.The test results of frozen soil structure and frozen heaving force with different cold junction temperature and different structural plane roughness show that the whole curve that the temperature of the whole soil column varies with the freezing time can be divided into four stages: rapid cooling phase I, transition stage II, quasi stable stage III and stable stage IV, and each stage duration is mainly decided by the cold end temperature boundary. Replenishment quantity, the amount of frost heaving, frost heaving shear stress variation can be divided into different stages through dividing time point according to the temperature, and different magnitude shows good regularity in each time. With increase of structural plane roughness and decrease of the cold end temperature, the final replenishment quantity becomes more and more, and the frost heave qualitative results and replenishment quantity are same. We build the relationships between replenishment quantity and frost heave in horizonal range that chosen by test factor and cold end temperature and structural plane roughness. Frost heaving shear force reach peak after forming stable temperature field, then it has been frozen soil and structure interaction stage, whose development has a connection with cold end temperature and structural plane roughness. Cold end temperature is higher, and the peak after the cut to frost heaving force showed a stable trend of decrease. With the decrease of the cold end temperature,-15℃ showed the basic stability of the change, and-20℃ presented a stable, reduced trendency. The larger the roughness is, the more obvious the fluctuations are,and the larger the frost heaving shear stress is, which showed a nonlinear growth relationship. The tangential frost heaving force showed relaxation phenomonon or stable change in stage v.Different cold end temperature of frozen soil structure frost heaving shear test results show that in the stage I, II, III that the soil samples hasn’t form a stable temperature field, two kinds of soil’s frost heave shear stress also showed a growth trendency. The frozen heaving force of silt showed a rising tendency in stage I, II, and III. In stage IV, cold end temperature of-15、-20℃ under heave shear stress occurs obvious attenuation, and cold end temperature of 10℃ powder soil frost heave shear stress at this stage continues to increase, but the increasing slope decreases. Heave clay shear stress increased rapidly in the first phase, the growth rate decreased with the prolonging of time. In stage IV, clay’s frozen heaving force under-20℃ presents linear attenuation while the frozen heaving force under-10℃ and-15℃presents linear increase.