Comparing Hydraulic Excavator and Bulldozer in Construction of Forest Road Standarad Cross Section in Different Slope Classes (Lattalar, Mazandaran Province)

Forest roads must be constructed according to technical standards and guidelines which have been published by the scientific and operational organizations. Recently, hydraulic excavators have been used beside the bulldozer for excavating the forest roads. Thus, it is necessary that their ability in construct of standard cross sections be compared. This study was conducted in Lattalar forest which is located south of Sari city (Mazandaran Province). 60 cross section samples were randomly selected for each machine in slope classes of 30-40, 40-50, 50-60 and 60-70%. Then, cross sections were taken by niveau and clinometer. The results in different slope classes showed that the hydraulic excavator and bulldozer had no significant effect on cut and fill slopes length and gradient. Roadbed width in bulldozer construction area was more than the hydraulic excavator at probability level of 1%. Also, there was a significant difference between the hydraulic excavator and bulldozer earthworking width in slope classes of 30-40 and 40-50% at probability level of 5 and 1%, respectively, whereas this difference was not significant in other slope classes. Finally, the average standard cross sections for hydraulic excavator and bulldozer were 89.96 and 84.81%, respectively.