Undrained Response and Liquefaction Behaviour of Non-Plastic Silty Sands Under Cyclic Loading

The undrained response and liquefaction behaviour of fine sand and silty sands consisting of 30% and 50% non-plastic fines were investigated in the present study. The effect of consolidation stress level, cyclic stress amplitude and amount of non-plastic fines on soil liquefaction have been studied through a systematically planned stress controlled cyclic triaxial tests. To examine the effect of consolidation pressure on liquefaction behaviour, the sand-silt specimens were prepared at 40% relative density and consolidated at pressures of 50, 100 and 200 kPa. To investigate the effect of fines content on liquefaction resistance of sands at constant postconsolidation void ratio, the sand-silt specimens were prepared at different relative densities of 20, 40 and 70%. The cyclic loading with CSR in the range of 0.075 to 0.275 was applied at a frequency of 1Hz in different tests. Test results show the influence of the addition of non-plastic fines to the sand on the reduction of liquefaction resistance. Soil specimens had exhibited higher resistance to liquefaction at low consolidation pressures and lower resistance at high consolidation pressures