Bulldozer and Hydraulic Excavator Traffi c Effect on Soil Bulk Density, Rolling Project and Tree Root Response

Abstract

Measuring soil bulk density after road excavating by heavy equipments is a key element to determine rolling intensity and root response to compaction. In this study, soil bulk density in crawler bulldozer and hydraulic excavator construction area was measured at two depths (0-10 and 10-20 cm) of sandy clay soil. Results showed that the soil compaction caused by different number of bulldozer passes was more than the excavator. The mean of soil bulk density in bulldozer construction area was about 1.74 gr cm-3.Thus, fi rst pass of roller (5.5 tones) was suffi cient to access the Aashto standard (1.75 gr cm-3). In contrast, the mean of soil bulk density in hydraulic excavator construction area was about 1.62 gr cm-3 and 6 roller passes was need to access the standard bulk density. Also, according to USDA NRCS classifi cation the bulldozer has restricted the root growth, whereas hydraulic excavator only may affect root growth. Rolling and leveling of the soil materials in bulldozer construction area should be done with the lightest rollers available and using the fewest passes possible.