Effect of size and loading rate on the uniaxial compression characteristics of frozen cement soil

In order to reveal the influence law of the effect of size and loading rate on the mechanical properties of frozen modified soil, uniaxial compression tests with different sizes and loading rates are carried out on the frozen cement modified soil. The influence of height-diameter ratio and loading rate on the strength and deformation characteristics of the specimen is discussed by analyzing the test data. The results show that the high-diameter ratio affects the stress-strain curve type and the post-peak deformation characteristics of the sample. With the increasing high-diameter ratio, the stress-strain curve shows a significant elastic yield point, and the post-peak brittleness increases, and the failure mode of the sample changes from splitting failure to single shear failure. The compressive strength, tangent modulus, initial yield modulus and strain at failure of the specimen can be fitted by using a parabola with the change of height-diameter ratio. For the comprehensive consideration, the test specimen with high-diameter ratio of 1.62~2.02 should be used. Under the conditions of temperature and loading rate, the uniaxial compressive stress-strain relationship of the frozen cement soil is strain softening. The compressive strength and initial yield strength of the frozen cement soil, similar to that of the frozen soil, increase with the decreasing temperature and the increasing loading rate. The relationship between the compressive strength and loading rate of the frozen cement soil at different temperatures can be expressed by using a power function. The lower the temperature, the greater the influence of the loading rate on the initial yield strength. Temperature and loading rate also have a great influence on the tangential modulus of the frozen cement soil. The tangent modulus has a linear relationship with temperature under different loading rates. The failure strain of the frozen cement soil increases with the decreasing temperature and the increasing loading rate, which varies from 1.94% to 6.94%. Under different loading rates, the failure strain has a power function relationship with temperature.