Effect of Non-Plastic Fines on Liquefaction Resistance and Pore Pressure Behavior of Fine Sand

The liquefaction behavior of sand-silt mixtures is highly debatable. Various conflicting opinions are prevalent in literature, as no unique test parameter exists that can be used to express the effect of non-plastic fines on liquefaction resistance of sand. Thus, the present study critically reviews and summarizes the effect of non-plastic fines on liquefaction resistance of sand along with the test parameter and the range of fines contents used to arrive at the given conclusion. In addition, several stress controlled cyclic triaxial tests were conducted on fine Yamuna sand with varying percentages of non-plastic silt. In the current study, relative density has been adopted as the standard test parameter, as it can be directly correlated to the standard penetration value in the field. Results shows that if non-plastic fines are added to sand, liquefaction resistance increases below the limiting silt content and then liquefaction resistance decreases as further addition of fines when relative density is constant. As long as the fines are non-plastic, the pore pressure behavior is similar to that of sands and can be represented with the simple models.