Evaluation of Cone Penetration Testing (CPT) for Use with Transportation Projects

Cone Penetration Testing (CPT) has many advantages as a means for subsurface investigation. CPT consists of pushing a steel cone into the ground and recording the penetration resistance using sensors. Pore pressure, shear wave velocity and other measurements can also be taken using CPT. Several states have incorporated CPT into their subsurface investigation programs and the Ohio Department of Transportation (ODOT) has funded this project as a first step toward routine use of CPT in Ohio. CPT soundings were completed at 20 sites throughout Ohio and the data were correlated with corresponding data obtained from standard penetration and laboratory testing. Clear correlation trends for the 17 different ODOT soil types were not obtained and a larger database is needed to improve the correlations. Guidelines for CPT machine operation and data analysis are presented. Existing correlations for engineering parameters are also discussed. CPT is expected to become a useful tool for ODOT subsurface exploration work and provide considerable cost savings over the long term.