Strength and stiffness characterizations of geo-materials composing unpaved roads using LFWD, DCP, and CDP tests

초록

To assess the condition of the geomaterials composing unpaved roads subjected to cyclic wheel loads by moving vehicles, it is necessary to evaluate the variations in mechanical properties with depth. In this study, a crossholetype dynamic cone penetrometer (CDP) was applied to characterize the stiffness of unpaved soil along its depth. In addition, light falling weight deflectometer (LFWD) and dynamic cone penetrometer (DCP) tests were conducted for a comparative analysis. The LFWD, DCP, and CDP tests were conducted on a newly constructed unpaved road after the application of 0, 200, and 400 cycles of wheel loads by a moving vehicle. From the experimental results, the strength and stiffness properties such as Evd, NDCP, and Vs, were obtained, and their incremental ratios were investigated according to the number of cyclic wheel loads. In addition, the improved relationships between Evd, NDCP, and Vs were constructed considering the strain influence factors with depth. This study demonstrates that CDP can be an efficient testing method to profile the stiffness of unpaved roads, and the relationships considering the strain influence factors may be used effectively for reasonably estimating the engineering properties.

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