Cone Penetration Testing: A Sound Method for Urban Archaeological Prospection

Abstract

Cone Penetration Testing (CPT) is a geotechnical in situ site investigation method and is widely applied in urbanized areas of the Netherlands. Approximately 20,000 CPTs are conducted in the Netherlands each year. The frequency of such testing, and the presence of archaeological deposits within the subsurface, results in a relatively high probability that archaeological deposits could be encountered during sounding. A significant amount of the results of these CPTs are freely available and are easily accessible in a national database. This combination of frequency and accessibility suggests that CPT could potentially be a very attractive tool for archaeological prospection. However, in practice, the integration of CPT in archaeology is poor. This is largely the result of the lack of a general overview of characteristics concerning the recognition of archaeological deposits in CPT data. This study explores the potential of CPTs for archaeological prospection in urbanized areas by characterizing archaeological deposits in CPT log data, with a special focus on the historical city centre of Amsterdam. In total, seven CPTs conducted at two archaeological sites in Amsterdam were analysed. A characterization based on the examined CPTs was subsequently used to identify archaeological deposits in 407 CPTs conducted in Amsterdam, deriving from the national database. This resulted in a map depicting the spatial distribution and thickness of archaeological deposits in the city centre of Amsterdam, solely based on CPTs. The map was validated using data from previously published archaeological reports.