THE STUDY OF THE DESTRUCTION PROCESS OF FROZEN AND THAWING SOILS EXPOSED TO THE SKIDDING SYSTEM

Wood logging in the forests of the cryolithozone is growing more urgent for the Russian Federation due to the depletion of available reserves of mature commercial forests in southern and Central Siberia, the Republic of Buryatia, and Khabarovsk Krai, while the development of woodworking enterprises in the Far Eastern Federal District. During the operation of modern forest machines, for instance wheeled forwarders, the issues of their efficiency, first of all, mobility and technological productivity in the specific production and geotechnical conditions are now becoming ever more relevant. These circumstances together with the necessity to minimize the anthropogenic load on the environment put forward the problem of optimizing the number of passes of the skidding system by one run into the most pressing ones. Special conditions for the operation of skidding systems take place in logging operations on frozen and thawing soils. In the first case, there is a sufficiently large volume of ice in the soil massif. The ice has a great impact on increasing the bearing capacity of the soil under the influence of the initial vertical load of the skidding system. In the second case, frozen soil is oversaturated with water when thawing; therefore, the natural bonds between the solid particles grow week, and the physical and mechanical properties of the soil lose their original values. The forwarder forms a rut in the immediate area of contact of the wheel with the soil. The larger the size of the area, the higher the force transferred to the soil for implementation of the necessary traction. We have developed the mathematical model of calculation of parameters of the destruction process of the thawing soil massif on the border with the permafrost zone. The model allows to make an assessment of hypothetical values of depth of the formed rut including engineering capabilities of forwarders and their maneuvering in the work environment at the design stage.