Liquefaction resistance of coarse sand-fine mixtures soil under two-way cyclic loading

Abstract

Soil liquefaction is one of the devastating consequences of earthquake hazards. Extensive study had been carried out to understand the factors affecting liquefaction resistance of sand and sand-fine mixtures, both in the laboratory and in-situ. However, the findings are still incomplete particularly in terms of particle size, grading characteristics and fines content of sand-fine mixtures. Hence, this paper aims to present the cyclic behaviour of coarse sandfine mixtures, in terms of liquefaction resistance under two-way cyclic triaxial loading tests. The cyclic loading tests under undrained condition had been performed with various percentage of kaolin as fines content. The sand-fine mixtures were prepared with 15% relative density and tested under 100 kPa of effective consolidation pressure. The cyclic triaxial loading tests were performed with a typical frequency of 1 Hz to simulate earthquake situation. The results showed that, with the increase of fines content in coarse sand-fine mixtures, the smaller the number of cycles required for the initiation of soil liquefaction. However, the number of cycles to initiate liquefaction increased back when fines content in the mixture was greater than 30%. As 30% fines content gave the lowest liquefaction resistance, this value is known as a threshold value in which it is the transition of sand domination to fines. The liquefaction resistance decreased with the increase of fines until it reached the threshold value but increased with fines content thereafter.