Freeze–Thaw Cycle Effects on the Energy Dissipation and Strength Characteristics of Alkali Metakaolin-Modified Cement Soil under Impact Loading

Abstract

To investigate freeze–thaw cycle effects on the energy dissipation and strength characteristics of cement soils under impact loading, impact compression tests were carried out using a split Hopkinson pressure bar on cement soils under various freeze–thaw cycles (0, 1, 3, 6 and 10 times). The Zhu–Wang–Tang (ZWT) model was modified to predict the relationship between deformation and strength in cement soils under various test conditions. The obtained test results revealed that the freeze–thaw cycle number and impact pressure had significant effects on the fractal dimension, strength and absorbed energy of cement soils and there existed a critical freeze–thaw cycle number. It was found that the increase of the freeze–thaw cycle number gradually decreased strength and absorbed energy and increased the fractal dimension. When freeze–thaw cycle number was between 0–6, strength, fractal dimension and absorbed energy were significantly changed. For freeze–thaw cycle numbers greater than 6, the effects of the above factors were gradually alleviated. A modified constitutive model was able to accurately describe cement soil mechanical responses under high strain rate conditions, and the relative error between the predicted and experimental results was in the range of ±7%.