Test on fracture toughness of saline red clay in severe cold areas

Abstract There are a large number of red clay in the Gobi area which can be used as engineering construction materials. However, the red clay in the cold region is relatively unstable. To the influence of existing cracks in saline red clay on the structure of raw soil in severe cold areas, uniaxial unconfined loading tests with initial cracks were carried out on red clay under different conditions by using a uniaxial compression test system. The results show the saline red clay’s K IC increases first and then decreases with the increase of water content. As the water content continues to increase, the change of K IC tends to ease. When the salt content is low, the change of K IC with water content is relatively gentle. With the increase in salt content, the changing trend of K IC is also increasing. With the increase in salt content, the overall trend of K IC is on the rise; before the precipitation of salt and ice crystals reaches saturation, the fracture toughness K IC of saline red clay increases with the decrease of temperature. The higher the salt content of saline red clay, the greater the growth rate of fracture toughness K IC with the decrease in temperature. the saline red clay with a moisture content of 25% ∼ 28% not only has a larger K IC but also has better ductility.