Investigation of Lateral Displacement Mechanism in Layered and Uniform Soil Models Subjected to Liquefaction-Induced Lateral Spreading

The phenomenon of liquefaction-induced lateral spreading has been responsible for causing catastrophic damage during the past earthquakes. LEAP project was formed with an objective of developing a large centrifuge database using different centrifuge facilities in an effort to characterize the median response of a sloping ground during lateral spreading. Further these databases provide a unique opportunity to verify and validate numerical modeling and contribute to the further enhancement of constitutive modeling involving soil liquefaction. However, such centrifuge and numerical analysis did not consider the presence of a layered sloping ground, which is most likely to be encountered in an ideal scenario. At the same time, it is also important to assess the lateral displacement mechanism within different models having larger soil variability. This shortcoming hinders the development of a performance-based design involving liquefaction-induced lateral spreading considering larger variability in soil conditions. To overcome this, we developed a series of centrifuge experiments. In the centrifuge plan, tests were developed for a uniform loose sand model, a uniform dense sand model and a multi-layer soil model. The result portrays the significantly different deformation mechanism for the uniform denser soil model as compared to a multi-layer soil model and a uniform loose sand model. The lateral soil displacements were found to be largest near the center array for all the models. Due to the occurrence of liquefaction-induced lateral spreading within the loose sand layer, the above denser soil layer could be dragged alongside, resulting in significant mobilization of shear strains towards the ground surface.