2024 Volume 10 Issue 12 Pages 350-354
Liquefaction has been often observed in sand deposits with fines particles during earthquakes. However, the effect of particle size ratio on the cyclic liquefaction of sand-fines mixtures is not extensively investigated. In this study, a series of undrained cyclic triaxial numerical tests were carried out emulating Toyoura sand mixed with non-plastic fines of different particle sizes using the discrete element method, to study the effects of fines content and particle size ratio on the cyclic liquefaction resistance of sand-fines binary mixtures at both the macroscopic and microscopic levels. The macroscopic behaviors, including the generation of excess pore water pressure and liquefaction resistance, and the microscopic behaviors, including the mechanical coordination number (MCN) and the mechanical redundancy index (IR), were investigated. Results show that initial liquefaction occurs when MCN is smaller than 3.0 or IR is smaller than 1.0. The liquefaction resistance decreases with the increase of fines content at a given void ratio. Both equivalent skeleton void ratio e* and initial mechanical coordination number (MCN0) can well characterize the liquefaction resistance of sand-fines mixtures for various fines contents and particle size ratios, which demonstrates the applicability of macroscopic parameter e* in characterizing effective inter-particle contacts in sand-fines mixtures.
