Correlation between the Standard Penetration Test and the Dynamic Cone Penetration Test for Sandy Soil

ABSTRACT: In geotechnical engineering, in-situ penetration tests have been widely used for site investigation in support of analysis and design. The Standard Penetration Test (SPT) is the most common in situ test for soil investigations in sandy soils. On the other hand, The Dynamic Cone Penetration Tests (DCPT) is a rapid inexpensive field test that can be used to assess the engineering properties of soils. However, correlation between the results of DCPT and soil properties or any other trusted field test is not well established yet. This study presents an evaluation of predictions SPT blow counts (NSPT) using Dynamic Cone Penetrometer Test. Data consisting SPT and DCPT was utilized to develop a correlation. Data of this study was drawn from 14 different sites located in north costal of Libya (City of Tripoli), served as the subject of SPT-DCPT correlations. The soil investigation program for each site included SPT borehole and adjacent DCPT tests. The validity of the proposed correlation was verified using test results on similar soils from five new sites. The developed correlation indicates that the relationship between the results of the two penetration tests is linear for sandy soils. Positive linear relationships were found between NSPT and NDCPT for sandy soils. To demonstrate the differences between the proposed and previous deterministic equations, comparative studies were performed. The suggested correlations may guide future more detailed correlations between these two in situ tests. NSPT predicted versus NSPT actual showed high correlation coefficients of 0.70.In summary, direct correlations between SPT and DCPT were produced, showed that the light DCPT is suitable for sandy soils with low density NSPT 30 blows/3.0 m or less, and allowing estimation of NSPT from DCPT.