ABSTRACT
The Cone Penetration Test (CPT) is a useful tool for soil profiling due to its near continuous data measurements, low cost and repeatability. When conducting designs or safety evaluations of slopes, it is often of interest to understand the undrained response of the soil at large strains. This behaviour can be defined in terms of the Undrained Brittleness Index (IB ) which relates the yield undrained shear strength to the steady state undrained shear strength. Over time, a number of field case histories where strain softening during undrained shear was deemed to have occurred have been assessed, and a relationship between corrected tip resistance and IB was proposed (Sadrekarimi, 2014). A quick clay test site and a silt test site in Norway included in a recently published open access geotechnical database were assessed. It was found that the method proposed by Sadrekarimi (2014) underestimated the IB for both the quick clay and silt test sites. It was also noted that there are some limitations with a popular screening method for identifying soils susceptible to strength loss during undrained shear.
