Small-strain shear modulus and liquefaction resistance of calcareous sand with non-plastic fines

Incorporation of nonplastic fines can dramatically affect the liquefaction resistance and stiffness of sands. This study aims to evaluate the influence of nonplastic fines on the liquefaction resistance and small-strain shear modulus of calcareous sand under cyclic loading. Forty-seven sets of undrained cyclic triaxial tests and companion bender element tests are conducted on reconstituted specimens. The cyclic behavior of clean sand and silty sand with varying fines content is examined with respect to the global void ratio, relative density, and granular skeleton void ratio. The findings demonstrate that the microscopic contacts between coarse and fine grains have a significant impact on the macroscopic behavior of sand-fines mixtures. The experimental findings are evaluated using the equivalent granular skeleton void ratio, which has been recognized as a suitable parameter to describe the overall effect of fines. The findings on calcareous sand with fines are supplemented and compared with published data in accordance with the semiempirical simplified approach for liquefaction triggering based on shear wave velocity.