ABSTRACT
Pumice-rich soils originating from volcanic eruptions are deposited in various parts of the world, such as in the central part of North Island, NZ. Since they are often encountered in engineering projects, their geotechnical characterisation is very important. Due to the highly crushable nature of pumice sands, there are concerns on the applicability of current empirical correlations, derived primarily from hard-grained sands, to pumice-rich soils. To understand their liquefaction characteristics, undisturbed soil samples were obtained from various pumice-rich sites in North Island using diverse sampling techniques. The samples were tested in the laboratory using cyclic triaxial apparatus and bender elements. At the same time, various field tests, such as CPT and Vs profiling, were conducted at the same sampling sites. The results clearly showed that crushable volcanic soils do not fit existing frameworks for liquefaction assessment and alternate methods are necessary to characterise them.
