Simulation of sandy soil degradation due to static liquefaction along with the uncertainty in soil properties

Abstract

For loose saturated sand, when subjected to static loading in undrained condition, the pore water pressure inside the soil tends to increase and the effective stress tends to decrease to zero resulting in the degradation of the soil structure, this phenomenon is called static liquefaction. Although static liquefaction has been studied for decades, it is still necessary to have a better understanding about this kind of soil behavior and its effect on the structure safety. In this research paper, the NorSand model was used to evaluate the static liquefaction of Hostun sand RF. The input parameters of the model were determined based on the experimental data. After that, the triaxial paradigm was built to modelized the triaxial experimental test. And then, the modeling sample was subjected to static loading until reaching the axial strain of 30%. This process gives the clear observation of the degradation of the modeling sample with the variation of deviator stress, pore water pressure in function of deformation development. The results show that under static loading, the deviator stress of the modeling sample reaches the maximum at very small axial strain, after that, the deviator stress decreases to almost 0 corresponding to degradation of soil structure. The modeling sample was liquefied at the end of loading process with zero effective stress condition. The results also present the input parameters for NorSand model which give the suitable fitting between the modeling and experimental results. Thereafter, the effect of relative density uncertainties on the soil degradation was studied. The model predictions show that for fully saturated loose sandy soil, maybe there is a critical value for the relative density, and when the relative density is greater than this value, the degradation on the soil structure will not occur. Finally, NorSand model can provide a theoretical basis for the design of structures with considering the uncertainties on soil parameters.