Pile group subjected to liquefaction (Numerical Modeling)

In the past earthquakes, deep foundations of structures (piles) in the loose saturated sand and susceptible to liquefaction have experienced major damages with the incurred costs. These damages become more considerable in coastal lands with moderate slope when experiencing lateral spreading. In this study, the effect of lateral spreading on deep foundations is studied by numerical simulation using OpenSees code. The results of a physical model test on shaking table are used in order to verify the numerical model. The physical model test was performed inside a rigid box with a 3x3 pile group. Three layers of soil placed with a slope of 7 percent (4 degrees) with the relative densities of 60%, 15%, and 80% respectively from top to the bottom in a way that the 1m think liquefiable layer was overlaid and underlaid with non-liquefiable layers of 0.25m thick. The results of numerical analysis confirmed that the prediction of excess pore water pressure in the soil and bending moment in the piles well agree with those of the experiment. However, the maximum displacement of the soil profile which was obtained from the numerical model at the end of the test was about 10% different from that of the measured value in the physical model.

Keywords:

Liquefaction , Lateral spreading , Deep foundation , Numerical simulation , OpenSees software