Investigation of Liquefaction Potential and Seismic Response of Gravelly Soils Using Shaking Table Tests

ABSTRACT: Recent earthquake case histories have consistently reported the occurrence of liquefaction in gravelly sandy soils, as observed during the 2016 Kaikoura Earthquake in New Zealand, and the 2018 Hualien Offshore Earthquake in Taiwan. These events revealed that liquefaction in gravelly deposits resulted in surface cracking and significant settlement, with sand boils occurring in some areas where ground surface cracks formed. The ejected materials were predominantly sand-gravel composites. Evaluating the liquefaction potential of gravelly soils remains challenging due to the availability of large-scale laboratory apparatuses required to perform tests satisfactorily on specimens composed of gravel-sized particles. Consequently, dynamic behavior of gravelly soils remains insufficiently understood. This study investigated the complex liquefaction mechanisms, seismic responses, and dynamic properties of gravelly soils through a series of shaking table tests on remolded saturated sand-gravel composites (40% gravel and 60% sand) derived from in-situ soil collected at Hualien Port, Taiwan. For specimen preparation, a wet pluviation technique was developed to reach the in-situ condition of the gravelly soils as reported from the site investigation report. The experimental results demonstrated that sand-gravel composites exhibit pronounced dilative behaviors during earthquake loading. Under the seismic loading conditions where maximum ground acceleration greater than 0.2 g, the soil specimens reached liquefaction, followed by a rapid dissipation of excess pore water pressure. These findings contribute to a deeper understanding of the behaviors of gravelly soils under seismic conditions and provide valuable insights for assessing liquefaction potential in similar soil types.