Large strain liquefaction characteristics of Christchurch boiled sand in torsional shear test

Abstract

In the period between 2010 and 2011, a series of Christchurch earthquake hit Christchurch City, New Zealand. The occurrences of severe liquefaction were repeatedly observed during the earthquakes. In addition, liquefaction-induced lateral deformation ranging from centimeters to several meters was observed. In this paper, a series of large strain undrained cyclic torsional shear tests were conducted on Christchurch boiled sand to evaluate its liquefaction resistance and large liquefaction-induced deformation characteristics. The boiled sand sample was retrieved at the liquefaction site along the Avon River after the earthquakes in February 2011 and in June 2011. It is found that the liquefaction characteristics of Christchurch sand at the normal strain level is similar to Toyoura sand, while higher liquefaction resistance for Christchurch sand was observed at the large strain level.