DEVELOPMENT OF RELATIONSHIP BETWEEN SPT AND DCPT BASED ON THE RELATIVE DENSITY OF SOILS (A CASE STUDY FROM THE KINGDOM OF SAUDI ARABIA)

In-situ penetration tests such as standard penetration tests (SPT) and dynamic cone penetration tests (DCPT) have been widely used in geotechnical engineering for site investigation studies to identify the strength characteristics of investigated soil deposits. Both tests are performed by dropping a hammer from a certain fall height and measuring a penetration depth per blow for the relevant depths. SPT is typically performed at depth intervals of about 1.50m and it has a wide range of well-known defined relationships for parameter acquisition of the soils. DCPT, on the other hand, is a rapid and inexpensive alternative for the penetration tests and obtains continuous data for the investigated soil depths. Considering the advantage of DCPT in providing continuous data compared to SPT, developing correlations between SPT and DCPT can provide a relatively more comprehensive data set to perform data collection for geotechnical design. In this study, a site-specific correlation was developed with comprehensive SPT and DCPT results from renewable energy fields in the Kingdom of Saudi Arabia (KSA). Furthermore, a sitespecific relative density class is derived from the SPT and DCPT results, in contrast to the relative density classes given in the literature. The relationship obtained for SPT and DCPT was found to be consistent with similar studies in the literature. The derived relationship can be used to obtain equivalent mechanical and physical soil properties for similar lithological conditions.