Experimental Study on Creep Characteristics of Interface between Warm Frozen Silt and Concrete with Different Roughness
In order to investigate the creep characteristics of the interface between high-temperature frozen soil and concrete,graded loading creep tests are conducted by using a self-developed large-scale creep shear apparatus under-1℃conditions.The frozen soil had a freezing temperature of-1℃,and the concrete surfaces have roughness values of 0,0.538,0.775 and 1.225 mm respectively.The graded loading conditions are analyzed for the creep curve patterns and failure characteristics of the interface.The graded loading curves are converted into individual loading curves to study the variation of creep rate with time.A shear stress-stable creep rate function is established to obtain the long-term strength values of the interface.Furthermore,a functional relationship between the long-term strength of interface and the surface roughness is developed to explore the mechanism by which roughness resists creep.The result shows that(1)there is a linear positive correlation between the graded loading strength and shear failure time of the high-temperature frozen soil-concrete interface with surface roughness,as the roughness increases,the shear failure interface shifts towards the interior of the soil,transitioning from interface slip failure to internal soil failure;(2)by using Chen's method,the graded loading curves are transformed into the respective loading curves,and the respective loading creep curves have the characteristics of decay and non-decay creep;(3)the relationship between stable creep rate and shear stress follow the Arrhenius equation,indicating that the long-term strength of the interface is only approximately 20%of the graded loading strength,which suggests a significant rheological effect in the high-temperature frozen soil-concrete interface;(4)the long-term strength of the interface increased linearly with increasing roughness,reaching a 220%increase in long-term strength when the roughness of the interface increased from 0 mm to 1.225 mm.Thus,increasing the roughness of the contact surface is an effective method to enhance the long-term strength of the interface between high-temperature frozen soil and concrete.
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