Effect of grading characteristics on the undrained shear strength of sand: review with new evidences

Abstract

In this paper, the shear strength of saturated pure sand and sand-silt mixture is evaluated by monotonic un- drained triaxial tests that were carried out on reconstituted specimens at same relative densities and a constant confin- ing pressure (σ30300 kPa). The test results were used to conclude on the effect of low non-plastic contents (0-20 %) and grading characteristics on the liquefaction resistance of the sand. The test results indicate that the undrained residual strength reduced with the increase of non-plastic fine con- tent. Also, shear strength of gap-graded sand mixed with low non-plastic fine content increases with decrease in ef- fective size (D50). In other words, in this state, we can use the D50 as a parameter to control of silty sand's undrained resistance. Besides, the undrained residual strength of pure sand specimens with same effective size increases due to increase of coefficient of uniformity (Cu).