On July 20, 2021, over 2000 ground subsidence events and collapses occurred in Zhengzhou, China, after a heavy rainstorm. These events were mostly caused by the reduced mechanical properties of loess under moistening and repeated dynamic loading. After the conducted dynamic triaxial tests considering varying moisture content, envelope pressure and 10,000 vibrations, the dynamic properties evolution of undisturbed loess under moistening has been clarified. The experimental results showed that the dynamic strain of undisturbed loess under moistening conditions increases gradually with increasing dynamic stress, following the Hardin-Drnevich hyperbolic model. The initial dynamic shear modulus, maximum dynamic shear stress, and dynamic strength decrease linearly with increasing moisture, while the dynamic strain is the opposite, and the damping ratio is less affected by the increased moisture. The dynamic strain rises with increasing dynamic stress and moisture content considering the same vibrations. Increased vibrations and greater moisture content under identical dynamic stress cause a faster accumulation of dynamic strain in undisturbed loess, making it more susceptible to damage. The results are of guiding significance for the evaluation and analysis of the dynamic properties of loess and provide technical support for disaster prevention and mitigation in Zhengzhou.
来源平台：BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT
