Experimental study on dynamic characteristics of Qingyang loess under different water contents

Abstract

The complex cyclic stress state such as traffic load and seismic load effects proposes a new challenge for seismic design in the loess area. This paper presents an analysis of the dynamic characteristics and physical and chemical properties of Q3 loess in Qingyang of Gansu Province, China. The dynamic modulus, damping ratio, dynamic strength, and residual strain characteristics of the samples of intact loess under different water content and the saturated compacted loess under different dry densities and different confining pressures were studied through the dynamic triaxial tests. The experimental results show that under the same conditions, the dynamic modulus and dynamic strength of the intact loess sample decrease with the increase of water content, and the residual strain increases with the increase of water content. The intact sample under the natural water content has a large maximum modulus (315.3 MPa) and dynamic strength (325 kPa, using yield criteria) and smaller residual strain. The dynamic modulus and dynamic strength of the compacted sample increase with the increase of dry density and confining pressure, and the residual strain decreases with the increase of dry density. Compared with other regions, the dynamic modulus and dynamic strength of Q3 loess in the Qingyang area are relatively large, indicating that the structure of Qingyang loess is very strong, and the sand content is higher than other areas. Particle analysis shows that Q3 loess in Qingyang belongs to sandy loess and sand content reached 51.4%. Under the action of dynamic stress, the Qingyang loess shows strong elasticity.