摘要: |
In the past decades, expansion projects of port facilities in California, USA, have been completed by placing hydraulic fills. These loose man-made fills and even their subjacent natural estuarine and marine deposits, have shown to be susceptible to liquefaction. The case of study presented in this research, the Port of Long Beach (POLB), Pier S, which is located within a few miles of the Newport-Inglewood and the Palm Verdes faults, offers a unique opportunity to use advanced constitutive soil models to study liquefaction. This research is presented to develop the following specific objectives: i) to calibrate constitutive model parameters to reproduce laboratory tests following different stress paths and shear strain levels; ii) to assess the use of an advanced constitutive soil model (UBC3D-PLM) to predict the soil behavior at the POLB, Pier S when a seismic event induces liquefaction; iii) to provide recommendations related to the permanent deformations of soils which could compromise the resiliency of the port. A semi-empirical evaluation of the liquefaction triggering and settlements were developed. Then, numerical analyses using the UBC3D-PLM soil model were used to determine the onset of liquefaction and estimate ground-induced settlements based on post-liquefaction excess pore pressure dissipation. This work presents the results of boundary value element simulations of cyclic un-drained direct simple shear and monotonic triaxial compression. Numerical simulations are performed to study the free-field response and behavior of hypothetical structures when an Operating and Contingency Level Earthquakes occur. The assessment of liquefaction susceptibility based on semi-empirical methods showed that Unit B is the only liquefiable layer under both earthquake levels. Generally, large discrepancies were observed in the calculation of liquefaction-induced ground settlements using classical semi-empirical approaches. |