Study on the effects of a low amount of non-plastic fines on soil liquefaction by dynamic centrifuge modeling

This paper presents a new experimental campaign investigating the influence of non-plastic fines on soil liquefaction behavior by dynamic centrifuge model tests. Non-plastic fines C500 were added to clean Hostun HN31 sand based on the constant host sand matrix concept. The characteristics and behavior of both clean sand and sand with fines are analyzed, including CPT resistance, small strain shear modulus, liquefaction resistance, post-shake re-consolidation, and model surface settlement. The low quantity of non-plastic fines has very limited effects on the CPT resistance and slightly increases the small strain shear modulus. In terms of liquefaction resistance, the presence of non-plastic fines has a considerable impact on medium-dense sand. For the medium dense case, the presence of 5% non-plastic fines increases the liquefaction resistance. However, when subjected to the successive shaking, the medium dense sand mixture became less resistant to liquefaction. For the case of dense sand, the presence of non-plastic fines on the liquefaction resistance of is not pronounced. For both medium-dense and dense sands, the presence of non-plastic fines significantly reduces the re-consolidation coefficient and increases surface settlement.