Evaluation of Highway Subgrade Compaction by Dynamic Cone Penetrometer

doi: 10.14456/mijet.2015.3

Abstract

This study established correlations between the number of blows from Dynamic Cone Penetrometer (DCP) tests and the compaction of the material that complied with the standard for soil subgrade set by Department of Highways, Thailand.

Soil samples from 12 construction sites were compacted to achieve various densities in the laboratory. The DCP tests were conducted at the center of the pits. A series of tests were then performed to determine soil classification and measure the trial compaction. The relationships between the number of DCP blows and compaction can be modeled as y = a ln(x)+b, where y is the compaction and x is the number of DCP blows. The model parameters were derived for four types of soil: A-2-4, A-3, A-4 and A-7-5.

The model was validated by comparing the predicted compaction with the measurements at three actual sites using a traditional sand cone method. The study sites were compacted by heavy machines. The predicted values agreed with the actual field measurements with the difference less than 5% and were obtained faster than using a typical current method.