NEW PROBABILISTIC APPROACH FOR LIQUEFACTION RESISTANCE OF SAND-SILT MIXTURES USING LABORATORYBASED SHEAR WAVE VELOCITY

This paper presents probabilistic diagrams for assessing liquefaction resistance of Firoozkooh clean sand and sand-silt mixtures with silt content up to 60% based on laboratory shear wave velocity results. In the work described herein, at first cyclic triaxial and resonant column tests were conducted on specimens with different densities. Then, laboratory results are compared to liquefaction criteria derived from seismic field measurements by Andrus and Stokoe-2000. At last, a data base consisting of laboratory shear wave velocity measurements is analyzed with probabilistic 30 method. The laboratory results indicated that using the existing field-based correlations will over estimate the cyclic resistance of the Firoozkooh sand-silt mixtures when silt content is 60%. Also, analyses based on 30 method showed that probability curve PL=0.32 agree with deterministic curves in Fc~5% and Fc=20% fines content. With increasing fines content up to 60%, probability curve PL=O.99 agree with field measurements by Andrus and Stokoe-2000.