Previous papers have presented correlations among the dynamic cone penetrometer, the dynamic probing type a, the standard penetration test, and the in situ california bearing ratio (CBR) test. As is known, these penetration tests are intended to determine, among other things, the bearing capacity of subgrades or of existing pavements without requiring the digging of test pits. This paper presents validation for these correlations as recently tested in four bearing capacity evaluations of subgrades and pavements on existing israeli roads and airport runways. The analysis was made possible by simultaneously carrying out the above penetration tests in combination with the in situ CBR test after test pits had been dug. Results indicate that the existing correlations are valid for translating the values of the above penetration tests into in situ CBR values. In addition, the above investigations indicated the following: (a) the layer thicknesses obtained by means of the penetration tests plausibly correspond to the thickness obtained in the test pits, and (b) the friction that develops during penetration, or the effect due to the overburden pressure, does not significantly influence the final results. Finally, it should be noted that the experience that has accumulated until now regarding an evaluation method based entirely on the above penetration tests proves the feasibility of the method for regular use in other evaluation projects.
Abstract