Soil stratigraphy from seismic piezocone data and multivariate clustering in alluvial soil deposits: Experience in the Lower Tagus Valley region

Abstract

The identification of soil stratigraphy at a given site is crucial for geotechnical analysis and design. This study addresses the delineation of soil stratigraphy from seismic piezocone penetration test (SCPTu) measurements. For this purpose, SCPTu data from an experimental site in the Lower Tagus Valley region (close to Lisbon) were compiled. Soil stratigraphy was obtained by applying a multivariate clustering approach using the direct measurements reported by SCPTu. The hierarchical clustering results were compared against the soil behaviour index profile. Moreover, the differences/similitudes obtained from multivariate clustering were validated by contrasting statistical results against the visual description of samples collected in the experimental site at Lower Tagus Valley using advanced sampling techniques; namely, Gel-Push sampler. The main findings showed that the clustering approach implemented herein detects and groups soil layers with similar soil behaviour types, allowing delineating the soil stratigraphy in multilayer alluvial soil deposits. (c) 2022 the Author(s).