Abstract: Undrained triaxial compression tests were performed on these reconstituted samples of Nanjing sands at three different relative densities and the results of an experimental study are presented. All tests were performed under monotonic loading. It is evaluated and analyzed to the stress-strain relationship and the probability of the static liquefaction. At low densities, samples exhibited typical strain-soften characteristics, in which peak strength arrived when the axial strain was below 1%; then deviator stress decreased rapidly. Moreover undrained triaxial tests showed static liquefaction ( zone stress difference) at the confining pressure of 50kPa and 100kPa. As confining pressure were increased, static liquefaction disappeared and the effective stress paths indicated increasing resistance to liquefaction. Compared with Nanjing fine sand, clean sand, which has no fine granular, didn’t exhibit the static liquefaction at low confining pressure. So it is hypothesized that the presence of fines (particles smaller than 0.075mm) in the soil structure doesn’t bring out the notable changes of and, but provides the highly compressibility. At media dense and dense Nanjing sand show the strain-harden characteristics, and the slope of critical stress path arrives 55°with high resistances of static liquefaction.

Key words: Nanjing sand, strength, consolidated-undrained triaxial test, static liquefaction