2022 Volume 78 Issue 3 Pages 225-234
In principle, the Japanese Industrial Standards call for soil compaction tests to be performed using a manual compactor. However, the use of an automatic compactor is also allowed if it can reproduce similar movements, and there are models that use various mechanisms to reproduce the lifting and rotational movements of rammers. Although automatic compactors are widely used, there is no way to evaluate their similarity to manual compactors, and the performance of various models is not known. Therefore, in this paper, we evaluate the performance of automatic compactors owned by 11 institutions and discuss their impact on soil dry density and the California Bearing Ratio (CBR). Although we find that the manual compactor provides uniform, ideal soil compaction, some automatic compactor models show large amounts of impact irregularity, greatly affecting density and CBR. Those effects can be summarized by the impact area, so we propose a simple method for measuring that area.
