Assessment of stability and operability of skidder on slopes of thawing soil mass during its interaction with a wheeled forest machine

Abstract

In the Russian Federation, a significant part of the forest fund is located on permafrost. Permafrost forests play a global ecological role by de-populating large amounts of carbon. However, when a forest reaches the age of obsolescence, this carbon is released into the atmosphere when the plantation decays. Therefore, from the ecological point of view, permafrost forests should be cut down when they reach the age of ripeness, in compliance with the requirements for their restoration. Many of the above-mentioned regions have large reserves of mature and overmature production forests, and a significant part of these reserves are located in hard-to-reach places, not only in relation to the development of the road network, but also by terrain relief. Currently, the vast majority of timber harvesting in Russia is done with modern machinery complexes, mainly including wheeled forest machines of different layout and purpose (harvesters, forwarders, skidders, etc.). With the help of special technical solutions, such as winches integrated into the transmission, or self-propelled winches (T-winch, ROB, Winch Assist), these machines can be successfully operated even on fairly steep slopes. The problem of negative effect of wheeled forest machines and skidding systems based on them not only stays actual, but also becomes even more urgent, as the ecosystems of mountain forests, forests on the slopes of hills, etc. are the most vulnerable and exposed to water and wind erosion. This article presents a mathematical model for reliable forecasting of rut depth and stability of a hairpin section during dynamic interaction of a forest machine with the soil on slopes, taking into account geometric parameters of the slope, the laws of the oscillating process of a forest machine with given values of speed and amortization characteristics of wheel-pair elements, the profile of the hairpin section and physical and mechanical properties of the soil in its boundaries, the weight of forest machines and the pressure in tires of wheel-pairs.