چكيده به لاتين
Liquefaction-induced horizontal displacements of soil layers, which are called here “Lateral Spreading”, have induced several damages to engineering infrastructures such as buildings, bridges, abutments, earth dams, ports, roads, and lifelines. Thus, many researchers have been attracted to study lateral spreading and its effects during past years. Using the displacement-based methods such as the p-y method for analyzing and designing the structures and buildings with a good estimation of displacements, one can design resistant buildings and infrastructure against liquefaction-induced displacements. Complex nature of lateral spreading and its dependence on several factors have made it difficult to study this phenomenon and to predict its displacements. In this study, it is tried to simulate the liquefaction-induced lateral spreading using finite element modeling in OpenSees software, and study the effects of various parameters on the permanent horizontal displacements of the lateral spreading. Additionally, regarding the different behavior of the near-fault and far-fault seismicity, estimating and calculating the horizontal displacements in near-fault sites have faced uncertainty. Therefore, the near-fault effects of earthquakes such as directivity pulses in velocity-time histories are considered in this study. First, by using PDMY02 constitutive model in OpenSees program, two case study sites in 1987 Superstition Hills and 1995 Kobe earthquakes that experienced lateral spreading and have available downhole and surface accelerographs and pore pressure data has been modeled and calibrated, and then, a parametric study has been done to evaluate the effects of the parameters on lateral spreading using this approach. The study showed that using the PDMY02 model in OpensSees program is a good method for studying the lateral spreading and its parameters. But it needs to be noted that according to the modeling of pore pressure build-up issues during the seismic loading in numerical models, further research must be conducted to evaluate the exact ability of the numerical methods to simulate the pore pressure build-up and liquefaction in near-fault sites with directivity pulses.
