Experimental study on cyclic loading and unloading of remolded loess under different stress paths

Aiming at the development characteristics of cumulative plastic strain of loess under different stress paths, this article takes reshaped loess as the research object, and conducts round-trip loading and unloading tests under different stress paths using a true tri-axial apparatus to explore the influence of different stress paths and stress amplitudes on the dynamic stress time history curve, hysteresis curve, backbone curve, and cumulative plastic strain curve of loess. The results reveal the effect of stress paths on the mechanical properties of remolded loess, and described the correlation between each principal stress and the ratio b of the middle principal stress, as well as the stress amplitude, and propose that the hysteresis curve of remolded loess is approximately elliptical, with the slope of the major axis increasing with the increase of the medium principal stress ratio b and decreasing with the increase of stress amplitude. As the value of the principal stress ratio b increasing, the stress-strain backbone curve increasing, and the cumulative plastic strain curve decreasing in sequence, and the cumulative plastic strain develops faster and enters a gentle stage. The research results provide a reference for solving relevant loess engineering problems.