Dynamic elastic modulus of Xianyang loess based on microscopic analysis: a qualitative evaluation

To explore the microscopic mechanism underpinning the dynamic characteristics of saturated loess, dynamic triaxial tests were conducted on saturated loess in Xianyang City, China. The tests were performed under dynamic loads of different waveforms, confining pressures, frequencies and amplitudes. Under each dynamic load, the test included two states: one stopped after 12 loading cycles, and the other is to vibrate to the failure state. Furthermore, a scanning electron microscope test was carried out on the undisturbed samples and the sheared dynamic triaxial samples. In this paper, the dynamic elastic modulus of samples is used to represent the dynamic characteristics, and parameters such as the diameter, average abundance, average fractal dimension, and directional probability entropy of the structural units and pores are selected to describe the microstructural characteristics of samples. The results show that the dynamic elastic modulus of samples decreases with increasing number of loading cycles or axial strain and finally stabilises when different types of dynamic loads are applied. The types of dynamic loads exert a significant influence on the microstructural parameters of structural units and pores.