Dynamic impact of wheeled skidders on forest soil in felling areas

Abstract

Soil compaction from wheeled vehicles poses a huge challenge for the forest ecosystems. Modeling the impact of skidding machines on the soil could help solve the problem. The present work seeks to construct a mathematical model of soil compaction under the cyclic dynamic loading of wheeled skidding machines using the vibration analysis method for elastic dynamic systems. The study found that 4 × 4, 6 × 6 and 8 × 8 forestry vehicles have similar amplitude-frequency characteristics regardless of driving speed and load. The analysis of soil compaction from dynamic loading revealed that loaded and unloaded skidder passes cause the least damage (21–31%) to forest roads compared to skid trails. As regards skid trails, 4 × 4 and 6 × 6 tractors were found to compact the soil by 23–50% in the first four passes. The subsequent passes will lead to 60–66% of compaction. Finally, 8 × 8 trucks cause 98–99% of soil compaction. The difference between the experimental and theoretical values of soil density does not exceed 12%. The unevenness coefficient of the soil compaction and the confidence interval fall within the acceptable range. The mathematical models are in good agreement with the experimental data and can be used to calculate the operating modes of wheeled forestry equipment.