12. Sample Disturbance in Deep Clay Samples

A large part of the uncertainty in geotechnical design originates from the soil properties, which are assessed through the site investigation. The use of high-quality soil block sampling may reduce these uncertainties, but such methods are only available for comparably shallow soil layers. Deeper soil layers are of interest for analysis of large progressive landslides, where the slide surface can reach a significant depth (>20 m), and where the assessment of the stability requires information about the strength, and in some cases the compressibility, of the soil. A case study of sample disturbance in such deep layers of clay is therefore discussed to highlight how sample disturbance can be detected in different types of measurements from a site investigation.