An Exploratory Study on the Effects of Liquefaction-Induced Sand Ejecta on Foundation Settlements Based on Moderate-Scale Shake Table Tests

Estimating the extent of sand ejecta effects on building settlements during earthquake, liquefaction is an important research question. Engineers currently need to rely on their judgment and relevant case history data because there is no available methodology that can be used, and details of the mechanism and correlations are unknown. This paper attempts to provide insight on the significance of ejecta by first reviewing literature on liquefaction-induced ejecta including case histories, geotechnical reconnaissance reports, and results from centrifuge tests. Second source of information consists of observations of ejecta occurrences near shallow foundations in a series of nine 1 g shake table experiments conducted at the University of Nevada, Reno, in which a particular attention was paid to the location, distance, and volume of ejecta occurrence in the experiments. Measurements of ejecta dimensions such as height and area were taken, and from those, the volume of ejecta was calculated assuming a conical geometry. The distribution of ejecta based on their volume is compared to measured foundation movements such as overall settlement and tilt. Preliminary conclusions of ejecta correlating with tilt and settlement of foundations are presented in this paper based on the experimental results.