Том 19, № 3 (2022)

In many countries around the world quite large reserves of forest resources are located on mountain slopes. Logging operations in mountainous areas significantly reduce productivity and increase risks for people and machinery. In many industrialized countries of the world machine logging methods dominate including harvesting operations on mountain slopes. Wheeled forest machines operating on mountain slopes are primarily equipped with special tracks. Ecosystems of mountainous forests are very vulnerable and violation of standard operations might result in excessive negative impact on soil, water and wind erosion processes. Especially dangerous for forest ecosystems on slopes is the process of rut formation under the influence of forest machine track driver. It is the track ruts that are concentrators of water and wind erosion. Besides, exceeding the load bearing capacity of the soil might lead to landslides and sliding of the machine down the slope. The article presents theoretical substantiation of permissible average pressure of the forest machine mover on a slope when the depth of the formed rut is limited. The authors present new dependences allowing in practice, without iterations, to calculate: the bearing capacity of the soil under the influence of the track mover, depending on the physical and mechanical properties of the soil. They take into account the angle of the slope; the depth of the rut formed under the influence of the track mover of the forest machine operating on the slope; admissible average pressure of a track vehicle on the subsoil, limited by the depth of the rut formed; coefficient of resistance to movement of a track vehicle moving along a slope; coefficient of traction of a track vehicle with the subsoil surface taking into account sliced subsoil weakening.

The objective of the research was to determine lateral reactions on tractor wheels from the side of the support surface in the "entrance to the turn" and "steady turn" sections of the circular loop-free turn. The objects of research included a mounted combined broad-cut unit KRSH-8,1+NP-5,4+LTZ-155+SST–18 and kinematic ways of turning the tractor (front steerable wheels; front and rear steerable wheels when turning relative to the frame in different directions). The calculation was performed by using a mathematical model of the curvilinear motion of a machine-tractor unit in an interactive programming environment Matlab/Simulink. It was assumed that the transition from rectilinear motion to a trajectory of great curvature followed the same law of uniform rotation of the steering wheel and, consequently, the same law of rotation of the steering wheels. The authors have established the negative effect of turning the rear wheels on the controllability and stability of the movement of the machine-tractor unit. When turning four controlled wheels, the instantaneous turning radius decreases, but the intensity and magnitude of its deviation from the specified trajectory of movement increase. The lateral force also increases with an increase in the speed of movement due to an increase in the centrifugal force of inertia and the moment of resistance to rotation due to a more intense dynamic effect of the micro profile of the support surface. In the simplest case, when the wheels of the front axle are the guides, the magnitude of the lateral reaction occurring on its wheels when entering a turn at a speed of 0.68 m / s is 6.6...8.8 times higher than on the wheels of the rear axle, and at a speed of 1.37 m / s it is 2.0... 2.3 times higher . With all steerable wheels the following results were obtained: at a speed of 0.68 m/s it was 1.16...1.20 times and at 1.37 m/s it was 1.50 ...1.52 times higher. The resulting character of the change in lateral reactions and their redistribution along the tractor axes is due to the values and ratios of tangential traction forces, rolling resistance forces and vertical forces on the wheels, their rolling conditions, changes in the position of the center of gravity of the machine-tractor unit, accelerations of vertical vibrations and geometric characteristics of turning. In all calculation options a more uniform distribution of lateral forces across the tractor axles when entering a turn with all controlled wheels obviously contributes to better controllability and stability of the unit, despite the fact that the vertical load on the front axle is 1.56...1.63 times higher than on the rear. At the same time the most favorable conditions of rolling wheels and realization of traction force occur. Thus, it is not advisable to control the tractor only with the front wheels when turning with frontal aggregation. Therefore, it is reasonable to use the method of turning the front and rear wheels at all stages of a circular loop-free turn to create the most favorable conditions for improving controllability and increasing the stability of movement on turns.

Modern road construction is performed by a flow method that ensures continuity of operation and requires timely and accurate center-control measurements and tracing. Therefore, the untimely restoration and fixing of destroyed center marks by inefficient methods, especially on the curves leads to a delay in the construction process. This might result in construction materials excess expenditure in case of road parameters violation or in machine hours and energy resources excess expenditure for defects removal by repeated poorly controlled movement of soil and building materials. Insufficient degree of detail in center marks distribution on the curves, as well as their unproductive or inaccurate restoration also leads to distortion of the designed curvilinear outlines of roads. Therefore it results in violations of the easement curve functions and in deterioration of their dynamic properties. In addition it leads to a decrease in visual clarity, riding quality and aesthetics of curves perception, thus negatively affecting drivers’ psychological status. All of the above leads to a decrease in technical and economic indicators and traffic safety. The purpose of the work is to improve the consistent analysis methodology and determination of standards of deviations from the design parameters of logging roads. Standards of deviations from design parameters in accordance with regulatory requirements are defined and recommendations are given for monitoring the construction of road curves. The results of studies using the theory of Markov random processes to predict the volume of control measurements for sequential analysis allowed the authors to determine the measurement intervals and to optimize their number and thus to reduce their total number by 4 times compared with the recommendations of the Construction Standards and Regulations (SNiP). The developed and researched decision engine of sequential analysis of logging roads allowed us to substantiate the proposed acceptance methodology of quality differentiated assessment of constructed logging roads geometric parameters.

Restoration of contaminated forest areas requires the use of cost-effective and environmentally friendly restoration methods due to natural and climatic conditions, the degree of damage and pollution, and the landscape and geochemical characteristics of disturbed lands. When developing measures for the restoration of used lands, including the disturbed ones, it is necessary to take into account the features of the northern regions: high vulnerability, long periods of self-restorability, inaccessibility of remote forest areas, a short period of positive temperatures, the need to restore the sanitary and hygienic state of disturbed territories to prevent the development of a negative impact on the environment. To determine the degree of pollution, a variant of mapping the site was considered and the degree of pollution was estimated. Water sampling in the contaminated zone testified to intensive processes of decomposition organic matter exceeding the MAC by 20-500 times. The death of vegetation and forest stands was noted. The penetration depth of pollution reached 95 cm. Herbaceous vegetation was fragmentarily preserved at a distance from the source of pollution. As the distance from the source of pollution increased, the projective cover degree with sedge also increased, and continuous thickets of beaked sedge (Carex Rostrata) appeared with some plants of string-rooted sedge (C. Chordorrhiza) and Magellanic sedge (C. Ppaupercula), marsh cinquefoil (Comarum Palustre) and cotton grass (Eriophorum Vaginatum). The authors considered three options for the reclamation of a polluted forest area: a mechanized method, a method including partial excavation and treatment of polluted matter in containers of various volume (from 9 to 40 cubic meters), and a two-stage treatment with microenzymes. The studies were performed in two modes: the natural process of biodegradation and additional aeration. Studies have confirmed the effectiveness of accelerating the process of decomposition of organic contaminants up to 9 days using the optimal dose of 15 g of the agent per 1 liter of contaminants. The treatment increased the pH of the medium from acidic to neutral one. The height of organic surface contamination layer was reduced to 0.3 mm in 9 days when the mixture was aerated. The second stage resulted in a decrease in the nitrogen concentration by 1.5–2 times. The effectiveness of the second agent was also confirmed by a decrease in the nitrogen concentration in the treated sample. The transparency of the solution increased by 2 - 2.5 times. According to the results of comparing three options for reclamation, the use of the new technology of two-stage biodegradation is 9 times cheaper than the use of a mechanized method, the time expenditure is 2 times less and amounts to 14 days.