Evaluation subgrade strength using dynamic cone penetrometer

The strength of the subgrade is an important consideration when designing working platforms for pavement structures. Furthermore, dynamic cone penetration tests are used to characterize the strength of the subgrade because determining the CBR value in the field requires the use of the equipment and is time-consuming. Instead, the CBR value of subgrade in the field can be predicted using other soil support tests, specifically the dynamic cone penetrometer index (DCPI), which has advanced as the most versatile rapid, in situ assessment device currently available for use in determining subgrade strength. The correlation of the DCPT index to CBR and its application in pavement performance assessment make it an appealing alternative to more expensive and time-consuming approaches. Internal friction angle and California bearing ratio values can be determined with great accuracy using correlation data of the dynamic cone resistance obtained from the instrumented DCP. This research implies that employing an instrumented DCP to determine subgrade strength could be a promising in-situ testing method. Therefore, field DCP tests were performed at six sites, each one kilometer away from the other, and a sample was taken for the laboratory’s tests of the California bearing ratio and the shear test. The results of the laboratory tests were close compared to the results of the DCP test, and therefore this examination is considered faster and easier to know the characteristics of the soil.