Uncertainty quantification in the analysis of liquefied soil response through Fuzzy Finite Element method

Abstract

In the present study, a scheme based on fuzzy finite element method was provided for uncertainty quantification of liquefied saturated soil response under dynamic loading. In this respect, the coupled dynamic equations which are known as u-p equations were used, and instead of crisp values for input parameters, including permeability coefficient, specific mass of the soil, compressibility and shear modulus, their fuzzy numbers were used. At the end, displacements and pore water pressure created during earthquake were reported as fuzzy numbers. After verifying procedures of fuzzy analysis by experimental results from the centrifuge model test No. 1 from the VELACS project, several membership grades were considered. Firstly, the effect of fuzzification of each input soil parameter investigated individually, and then effect of considering all four input soil parameters as fuzzy numbers was analyzed by developed method. It was indicated that results of the analysis during the effective time of the earthquake were strongly influenced by the shear modulus and partially by compressibility modulus, and after this time, it was mainly affected by the permeability coefficient. Also considering uncertainty nature of specific mass of the soil had no significant effect on the results.