Equivalent granular void ratio and state parameters for loose clean sand with small amount of fines
Recent studies suggest that the undrained liquefaction behaviour of sand with finds is more complicated than clean sand, and their interpretation under Critical State Soil Mechanics (CSSM) is a challenge. It is also reported that void ratio is not a good state variable for sand with fines. The inactive contribution of fines to sand microstructure is responsible for the anomaly. To resolve this problem, it is proposed to use equivalent granular void ratio instead of void ratio. It is found that a unique Steady State Line (SSL) called equivalent granular SSL can be achieved for sand with fines by using of the equivalent granular void ratio. This equivalent granular SSL was used as the reference line to calculate state parameters. It is found that these state parameters can successfully predict stress path responses of sand with fines in undrained shearing.