The Effect of Non-Plastic Fines on Pore Pressure Generation Characteristics in Saturated Sands

The generation of pore water pressure in a saturated soil beneath level ground during an earthquake is generally assumed to be due to the cyclic shear strains. This study presents the results of strain-controlled cyclic triaxial tests on silty sands. The tests were performed to evaluate pore pressure generation characteristics of silty sands under cyclic loading. The sand specimens were tested contains 0%, 10%, 20%, and 30% silt content. The results show that overall void ratio decreases during the saturation and consolidation process, this effect increases with increasing fines content. Also, excess pore water pressure decreases with increasing silt content up to 10%. At silt contents greater than 10% up to 30%, excess pore pressure increased because, the sand skeleton void ratio is greater than the maximum void ratio of the clean sand, thus the sand grain-to-grain contact is removed and the response is controlled by the silt matrix. Keywords: Cyclic triaxial, Liquefaction, Non-plastic fines, Pore water pressure, Volume compressibility, Strain-controlled tests, Threshold shear strain.