Sensitivity in volcaniclastic silts in North Island, New Zealand

Abstract

New Zealand soils of volcanic and volcaniclastic origin are often sensitive to remoulding, having a high ratio of peak to remoulded strength. This study has focused on silty, air-fall deposits related to the eruption of the Kidnappers ignimbrite. A field shear vane was used to measure shear strength at field exposures. Samples were taken to complete more detailed testing in a laboratory environment including Atterberg limits, drained and undrained triaxial strength, and ring shear testing. Samples were also collected for X-Ray diffraction and scanning electron microscopy to study the mineralogy and microstructure of the soils. Comparisons are drawn between New Zealand sensitive soils and those from Canada and Norway.