In the case of compression oy bulldozer. The soil is not compacted by in impact-force, but by the weight of the machine and vibrations. As the contact pressures caused by a bulldozer are smaller than that by the standard compaction test, the effects of the lower pressure on soils must be examined.
The auther has performed a few experiments uni-axial confined compression test, and the results so far are as follows:
(1) In the case of a contact pressure smaller than 2. 0 kg/cm2, the concave features are seen on Proctor's curve, i. e. the minimum value of γ_d is confirmed.
(2) The moisture ratio at the minimum value of γ_d is nearly equal to the value of Proctor's wopt.
(3) The soil behavior in these compactions may be discussed from the point of view of the bulkingtheory concerned with the capillary forces of soil water