MODIFICATION OF A CONSTITUTIVE MODEL IN THE FRAMEWORK OF A MULTILAMINATE METHOD FOR POST-LIQUEFACTION SAND

Abstract

THE ESTIMATION OF THE VALUE AND DIRECTION OF POST-LIQUEFACTION DEFORMATIONS IS ONE OF THE MOST CHALLENGING ISSUES IN THE MODELLING OF LIQUEFACTION SOIL, DUE TO THE INHERENT AND INDUCED ANISOTROPY. IT IS VERY IMPORTANT IN THE SCIENCE OF SOIL-CONSTITUTIVE MODELS TO PRESENT A SIMPLE AND COMPREHENSIVE MODEL FOR THE PREDICTION OF FABRIC ANISOTROPY EFFECTS IN PRE- AND POST-LIQUEFACTION BEHAVIOUR IN GRANULAR SOIL. IN THE FRAMEWORK OF THE MULTILAMINATE METHOD, 17 PLANES WITH PRE-DETERMINED DIRECTIONS ARE DEFINED ,INSTEAD OF DEFINING ALL OCCURRENCES DEPENDING ON THE DIRECTION IN THREE PLANES PERPENDICULAR TO EACH OTHER IN A CARTESIAN COORDINATE SYSTEM. AS A RESULT, CALCULATION ACCURACY IS INCREASED IN THE POINT DUE TO THE EFFECTIVENESS OF THE BEHAVIOURS IN DIFFERENT DIRECTIONS. IN THE PRESENT STUDY, AFTER MODIFYING AN ADVANCED MODEL BY REMOVING CONSTANTS RELATED TO THE FABRIC EFFECT AND USING LOWER CONSTANTS, THE PRECISION OF MODEL PERFORMANCE AFTER THE REMOVAL OF CONSTANTS WAS STUDIED AND COMPARED WITH EXPERIMENTAL RESULTS IN DIFFERENT MONOTONIC, CYCLIC, DRAINED, AND UNDRAINED LOADING CONDITIONS. AFTER THIS, THE FORMATION OF STRESS AND STRAIN IN 17 PLANES WAS EVALUATED IN TERMS OF PRE- AND POST-LIQUEFACTION, WITH MONOTONIC AND CYCLIC LOADINGS. THE STUDY OF THE CURVES SHOWS INDUCED ANISOTROPY IN DIFFERENT DIRECTIONS OF SANDY SOIL AND THUS PROVES THE CAPABILITY OF THE MODEL IN THIS REGARD.