Correlations between SPT, CPT, and Vs for Reclaimed Lands near Dubai

Artificial islands near Dubai were constructed with geomaterials of significant gravel content from other areas of the United Arab Emirates (UAE). The fills were dynamically compacted and their present geotechnical properties are unknown. Large development projects are being proposed on the islands that will require extensive field testing to characterize the fills because existing correlations developed for nearby natural soils are not representative. The main focus of this study is to develop correlations between Standard Penetration Test (SPT), Cone Penetration Tests (CPT), and shear wave velocity (Vs) measurements applicable to the compacted fills with high gravel content. More than fifty (50) SPT and similar number of CPT tests are performed on a large area of the island. A number of Multi-Channel Analysis of Surface Waves (MASW) and Downhole Seismic (DHS) tests are conducted to measure the distribution of Vs with depth and imaging. The data is analyzed to develop correlations between SPT and CPT and between SPT and Vs. The proposed correlation between SPT and CPT generally does not agree with existing correlations for coarse grained soils. This study predicts larger values of tip resistance (q_c) with N₆₀ values. The predicted Vs values as function of N₆₀; however, are comparable with some prediction equations in the literature. The Vs values from MASW and DHS for the fill are comparable on average; however, reliability of DHS increases with depth. The results from all tests reveal the inadequacy of earlier dynamic compaction in achieving consistent and uniform densification.