8th International Conference on Earthquake Geotechnical Engineering (ICEGE), 2024, Osaka
Following the September 4th 2010 Mw7.1 and February 22nd 2011 Mw6.2 Earthquakes in Canterbury, New Zealand, liquefaction-induced lateral spreading was observed along the Avon and Heathcote rivers. Detailed field measurements following the events provide a benchmark to evaluate the efficacy of lateral spreading prediction models under real world conditions. Show more…This paper presents the development of 2D effective stress finite difference models in FLAC2D of two transects along the rivers, and compares numerical results to observed displacements for the two major seismic events. The liquefiable soil was modelled with the PM4Sand model, and an automated calibration procedure was developed to determine the model inputs based on CPT results. The displacements during the earthquake excitation and post-shaking during pore pressure dissipation were quantified. Overall the simulations show reasonably consistent ground displacements at the channel free-face for both events and both transects, though recognising significant uncertainties in the simulations and field measurements. The results of the numerical simulations highlight the importance of both geometric (notably the channel width) and soil properties as key factors that influence lateral spreading displacements. The simulation results provide some confidence that detailed finite difference models can reasonably capture the expected level of ground movement during a lateral spreading event. Show less…
