Dynamic properties of sand with different contents of clay

In this study, a series of dynamic triaxial tests and corresponding simulations using discrete element method (DEM) were conducted on sand with different clay particle contents. The development of pore pressure, axial strain, stress path, and stress-strain curve were analyzed. The contact and pore structure characteristics were further examined through electron microscopy. Subsequently, the concept of a contact-to-particle ratio is proposed to describe the connection behavior. The results show that the influence of the clay particle content on the liquefaction resistance is not monotonous. With an increase in clay particle content, the effective stress of sand cannot reach zero. However, the increase in clay particles reduced the permeability coefficient of the sand, which resulted in weak liquefaction resistance of sand. When clay particle content reached 30-35%, the stress-strain curve failed at an early stage. The contact-to-particle ratio was the smallest when the clay particle content was 35%, that effective contact of the particles is only 15% of that in the pure sand sample. When clay content reached 40-50%, the sand sample gradually exhibited the characteristics of clay.