ABSTRACT
The north Irish Sea is earmarked for the development of several offshore wind farms. The complex Quaternary history of this area has resulted in a legacy of geotechnically challenging deposits, including heterogeneous glacial deposits, soft sediments and gas-charged sediments. Multichannel Analysis of Surface Waves (MASW) is commonly used onshore to produce shear wave velocity (Vs) profiles and is increasingly being used offshore (UMASW). When used in tandem with in-situ Cone Penetration Testing (CPTU) profiles it is a powerful tool for characterising offshore deposits. UMASW profiles were obtained from sites across the north Irish Sea coincident with CPTU profiles. Vs profiles from UMASW show good agreement with CPTU parameters in a range of geological settings. The purpose of this paper is to present a characterisation of geological deposits using a combined approach of CPTU and UMASW. By doing so the aim is to further develop classification charts that can give reliable characterisations of offshore deposits by combing non-invasive geophysical techniques and traditional CPTU.
