Vol 20, No 1 (2023)
Articles
Calculation of the upgraded flat unit strength
Abstract
Timber floating on small and medium-sized rivers requires the improvement of flat-flow units characterized by high transport and performance indices. The authors present a modernized flat-flow unit which has high transport and performance indices. A simplified design of the unit allows its manufacturing in a flat-flow machine. This is achieved when rows of round timber are stacked between the lower and upper transverse stickers, where the upper transverse stickers previously pressed along the entire length to the round timber in the flat machine are connected to the lower transverse stickers with raft cables. The practical operation of the considered flat raft unit for the initial timber floating requires its key transport and performance indices calculation with the focus on the calculation of the raft unit strength. The calculation method substantiates the geometric parameters of the lower and upper transverse stickers, rings with a ribbed inner surface, chains and lanyards. The justification of the geometric parameters of the lower and upper transverse stickers was based on taking into account all types of stresses arising in the transverse stickers subjected to various external and internal forces, the maximum allowable stress of the wood of the stickers and a set of safety factors. To justify the parameters of the raft cables the authors took into account deformations occurring in rings with a ribbed inner surface, chains and lanyards subjected to maximum force, the maximum allowable stress of the raft cables material and the safety factor. Dependency for calculating the diameter in the upper section of the lower and upper transverse stickers is obtained. Dependencies for calculating the thickness of rings with a ribbed inner surface and the diameter of the welded chain are also obtained, the condition for choosing lanyards is determined. Timber floating based on a modernized flat raft unit implementation with the mandatory calculation of the geometric parameters of the lower and upper transverse stickers and raft cables according to the presented methodology will allow a trouble-free timber floating with high economic efficiency.
Resources and Technology. 2023;20(1):1-25
1-25
Classification of slopes with thawing soils according to the geotechnical conditions of their interaction with the forest machine movers
Abstract
Gradual depletion of stocks of ripe and overgrown forests in accessible forests necessitates the development of less accessible woodlands. Most of the forest fund in the Russian Federation is located in permafrost zone. The forests of the cryolithic zone, as well as the forests on the slopes of mountains and hills, are considered the most vulnerable ones in ecological terms. A significant part of the forests in the cryolithic zone is located on inconvenient terrain that is on the slopes of mountains and hills. But effective forest exploitation of such forests is important. Based on the particular complexity of work planning in the conditions under consideration, both from the point of view of operational and environmental efficiency, scientifically based methodological support for decision-making process is needed including the choice of machinery and equipment and the scheme of a specific cutting area exploitation. The article substantiates the classification of soil strength and its compliance with geotechnical conditions of logging on the slopes with thawing soils. The classification allows us to assess the operability of the skidding track (technological corridor) and its effectiveness when using various forest machines and skidding systems.
Resources and Technology. 2023;20(1):26-41
26-41
Prospects for further research on the improvement of tracked forest vehicles
Abstract
The analysis of the current situation in the domestic forestry science and forestry engineering allowed the authors to describe the prospects for expanding the production and use of tracked forest vehicles in logging production and forestry. The advantages and disadvantages of wheeled and tracked forest vehicles are analyzed, both from the point of view of their operational and environmental efficiency, including operating conditions in forests in the permafrost zone. It is shown that domestic forestry machines based on tracked chassis have good prospects for wide application in forestry and in logging production. These machines, compared with the wheeled ones, are much more environmentally friendly, much cheaper to manufacture and operate. Moreover, Russian machine-building plants have extensive experience in the production of such machines. A simpler design of tracked machines ensures 100% manufacture of components within our country. The authors claim the necessity of regulatory control of the ecological environmental impact of forest machines operation, in particular, permissible pressure on the soil, the depth of the track left, the degree of soil compaction.
Resources and Technology. 2023;20(1):42-86
42-86
The effect of the chipping log sections length on the fractional composition of wooden chips
Abstract
It was noticed that in the course of actual manufacturing process the length of the pulpwood fed into the disk chipper affects the fractional composition of the chips. A theoretical study confirmed the existence of a correlation between the length of the pulpwood and the fractional composition of the chips. In particular, the result of the theoretical study showed that the fractional composition of the chips manufactured from sections of logs chipped by a disk chipper depends on their length. Analytical research demonstrated that with the increased length of the chipped segment (all other things being equal), the yield of the standard chips increased. Thus, two tasks were set to be solved in an experimental way. The first one was to check the effect of the log chipping sections length on the fractional composition of the chips produced by a disk chipper. The second one was to establish how the proportion of short length sections of logs in the total flow of raw material supplied to the disk chipper affects the fractional composition of chips under actual industrial conditions. The experimental results showed that there was a correlation between the length of a log section crushed in a disk chipper and the fractional composition of the resulting chips when both upper and lower methods of chip evacuation were used. A decrease in the length of the crushed section in the studied cutting speed range (17-38 m/s) led to a decrease in the proportion of the standard fraction in the chips. During the industrial experiment, a correlation was also established between the proportion of short sections of logs in the total batch of raw material supplied to the chipper and the fractional composition of the chips produced. The dependences of the mass content of various fractions of wood chips can be approximated by linear expressions with a reasonable degree of accuracy. Studies in industrial conditions showed that a decrease in the proportion of log sections with a length of no more than 0.8 m in the total amount of pulpwood from 68 to 38% led to an increase in the yield of the standard fraction in wood chips by 2.5%. At the same time, there was also a decrease in the proportions of oversized and small fractions by 0.8% and 1.7%, respectively. The regression equations obtained from the results of the industrial experiment made it possible to establish the maximum permissible proportion of short sections of logs in the flow of raw material. Thus, the manufacture of wood chips that meets the fractional composition requirements for wood chips of the C1 brand according to GOST 15815-83 is possible in a chipper with a knife disk with a diameter of 2500 mm, if the proportion of log sections with a length of no more than 0.8 m does not exceed 45% in the flow of pulpwood supplied for chipping.
Resources and Technology. 2023;20(1):87-111
87-111
Increasing the environmental safety of the R-21 "Kola" road as a central element of the Karelian forest infrastructure
Abstract
The article deals with the problem of water bodies’ pollution with surface rain and melts runoffs containing suspended solids and oil products from the roadway. The authors show that the R-21 "Kola" road located in the Republic of Karelia is a typical representative of the roads of this group. An analysis of the operating conditions of this transport highway showed that it not only serves as a transit corridor for other regions of Russia, but also represents a key element that links the enterprises of the forestry complex of the entire northwestern federal district into a single logistics chain. To reduce the negative impact on the water bodies adjacent to the highway the authors proposed wastewater disposal management to remove surface waters to gutters. These waters will be disposed down road slopes with their subsequent treatment in gravity hydraulic structures before final discharge into water bodies. The authors established the boundaries of water bodies crossed by the R-21 "Kola" highway by using geographic information systems. The number and size of water protection zones were determined and it was shown that these zones occurred every second kilometer on average. This number is not enough to ensure the environmental safety of the surrounding areas. The paper substantiates the need to organize additional complexes for surface waters diversion and treatment throughout the entire highway. The calculations performed by the authors to determine the flow of rain and melt water from existing sections of the road within the water protection zones allowed them to propose a method for drainage systems unification. The expediency of installing drainage gutters every 50–200 m was determined. This measure will ensure the diversion and treatment of surface runoffs with the required intensity of 0,6–1,9 l / s. An increase of the runoff collecting area might lead to uncontrolled overflow of gutters and overflow of polluted water onto the road slope without treatment thus negatively affecting the ecological state of roadside areas and adjacent water bodies.
Resources and Technology. 2023;20(1):112-128
112-128