Timber hauler. Modern problems of science and education. Selecting a scheme for transport development of a cutting area
The article proposes a mathematical model and methodology that makes it possible to select a rational scheme for the transport and technological development of a forest area, taking into account the reduction of costs when performing a set of preparatory and main operations for the development of scattered cutting areas and characterized by the possibility of an integrated solution to the problems of performing the main movement operations of skidding and removal of wood from analysis of the placement on the territory of the forest block, in addition to the block clearings limiting its perimeter, additional temporary logging trails. The justification of paths with minimal costs for laying skids and hauling timber between all pairs of analyzed areas on the territory of a forest block is based on a sequence of k transformations of the original matrix and dividing the main problem into smaller subtasks, which eliminates the repeated consideration of costs for laying main skids in the analysis networks of skidding paths connecting cutting areas with loading points during quarterly development of forest areas.
timber hauler
graph theory
loading point
removal of timber
skidding
logging
forest quarter
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The problem of increasing the efficiency of the functioning of the primary timber transport network of forestry enterprises has been given attention in the research of scientists from PetrSU, VGLTA, SPbLTA, MSUL, TsNIIME, SSC LPK, PSTU, etc.
The problems of substantiating the feasibility of constructing temporary logging bridges during the development of small cutting areas were analyzed in the works. The work proposes dependencies for drawing up a program for determining the critical value of the volume of timber removal from a cutting area, at which it is advisable to place a temporary timber hauling fence adjacent directly to the cutting area, and nomograms are constructed to simplify calculations in real production conditions. Recommendations are given for hauling timber with tractors along the main drags outside the cutting area to a loading point adjacent to the logging road or quarterly clearing on the border of the forest block, if the planned volume of timber removal is less than a justified critical value.
However, these studies do not imply an effective analysis of the possibility of placing temporary logging roads within the block in the presence and joint consideration of the possibility of hauling timber to the block clearings that limit the perimeter of the forest block in the conditions of a well-developed, operating block network on the leased area and the simultaneous development of several located within the block forest areas with varying volumes of logging work on their territory.
Purpose of the study: Justification of a rational technological scheme for the placement of temporary timber hauling tracks and a network of loading points during the quarterly development of forest areas, taking into account the existing quarterly clearings limiting the perimeter of the forest quarter.
Material and research methods. The proposed methodology is based on the implementation of a method for solving the p-median problem in terms of integer programming. The sequence of calculations involves comparing the analyzed sections with the vertices of the graph. In this case, the number of graph vertices depends on the number of developed cutting areas and can be increased depending on natural conditions and the required degree of detail of the calculation results by dividing large cutting areas into parts and displaying them on the graph as its new vertices. Simultaneously with the vertices of the graph characterizing the developed cutting areas within the forest block, the graph marks the vertices characterizing the possible locations of loading points nearby, limiting the block of quarterly clearings. Possible options for laying main drags on its territory are marked as the edges of the graph, their lengths and the projected costs of their placement are recorded.
The vertices of the resulting graph are numbered in the following sequence: initially the vertices of the graph corresponding to the areas marked near the quarterly clearings are numbered, and then all the analyzed cutting areas within the quarter are numbered.
The costs of arranging loading points at each of the analyzed sites are predicted. If, for some reason, placing a loading point on the cutting area is impossible, then the costs of its arrangement are equal to. The volumes of harvested wood at each cutting area are predicted.
Let us take - a distribution matrix in which
Let us assume that if the peak is the median peak (i.e., on this section of the forest block there is a loading point and there are access roads that make it possible to transport wood using logging vehicles to a timber warehouse) and, in the case when the location of loading point and arrangement of timber transport routes.
The proposed methodology involves reducing the total costs of maintaining existing quarterly clearings in operating condition, placing additional logging roads and main drags on the territory of the forest district, arranging a given number of loading points, hauling wood to them, and takes into account the costs of hauling wood to the timber warehouse. The use of the technique involves minimizing the objective function:
The physical meaning of the terms taken into account in the objective function is as follows:
· the first term characterizes the total costs of laying all the main trails connecting the developed areas in the forest area and hauling timber along them to loading points:
where are the minimum total costs for laying main trails connecting sections i and j, and for hauling wood between designated sections, i.e.;
The second term takes into account the total cost of arranging loading points:
where is the cost of placing a loading point on - site, units;
· the third term takes into account the possible costs of laying a logging road:
Where 
various options for laying transport routes from the analyzed area to areas located at quarterly clearings, corresponding to the minimum costs for laying main drags (temporary logging roads), m; - number of plots adjacent to quarterly clearings, pcs.; - additional costs associated with the conversion of 1 l.m. main drag to the logging road, e.g.;
· the fourth term takes into account the additional costs of moving logging vehicles along additional logging roads, analysis of the feasibility of placing them in a forest area is an integral part of this methodology:
where is the cost of a machine shift of timber transport vehicles involved in timber removal, unit units; - harvested timber stock in each of the analyzed areas, m3; - average speed of logging vehicles in idle and cargo directions along additional logging roads laid in the forest area, m/s; - average load per trip of timber transport vehicles, m3; - number of operating hours of timber transport vehicles per shift, hours; - coefficient of utilization of the shift time of timber transport vehicles; 
- minimum distances from the analyzed area, located at the quarterly clearing to the corner of the forest block in the direction of which the timber is transported to the timber warehouse.
Restrictions imposed on the objective function:
For all analyzed areas, a condition must be met to ensure that any analyzed vertex is attached to one and only one median vertex (i.e., any analyzed area (cutting area) on the territory of a forest block is connected via a main drag to only one loading point).
On the territory of the forest block, to ensure the implementation of all logging operations, one or more loading points must be located (i.e., in the graph characterizing the areas on the territory of the forest block there must be at least p median vertices). The fulfillment of this condition is ensured by the introduced restriction on the number of loading points in the forest area.
The number of options used in the analysis for locating loading points near the quarterly clearing must meet the following condition:
For all analyzed areas, a condition must be met that guarantees that any analyzed vertex can only be attached to a vertex included in the median set (i.e. if , then , since the attachment of any analyzed area (cutting area) on the territory of a forest quarter through the backbone a drag or a network of main drags to the second section can be justified only if a loading point is located at the second section).
Values are integers and can be in the range . Similar to the method for solving the p-median problem in terms of integer programming, it is advisable to transform this condition into the expression:
Each plot (cutting area) taken as a median peak must be connected by a main trail or a network of trunk trails and quarterly clearings with one or more plots located on the border of the forest block.
Justification of the minimum costs for laying drags and skidding between all
pairs of analyzed sections of the forest block
To solve this problem, it is necessary to substantiate the methodology for calculating the minimum total costs for laying main drags and skidding wood between all pairs of analyzed areas and.
To implement this task, mathematical dependencies have been derived that take into account the peculiarities of the technological process of logging operations in the conditions of quarterly development of forest fund areas and the diversity of natural and production conditions of the analyzed areas, which allow filling and transforming all successive matrices, intermediate values for justifying the minimum costs for laying skids and skidding between all pairs of analyzed sections of the forest block.
To fill out the initial matrix, covering the values of the minimum total costs for laying main drags and skidding of wood only between the nearest pairs of analyzed areas and directly connected to each other by the main drag, without realizing the possibility of laying it through the territory of another cutting area, a mathematical relationship is proposed:
where is the cost of laying a main drag between areas and located on the territory of the forest quarter, unit units; - distance between sections and , m; - cost of a machine shift of equipment involved in timber skidding, unit units; - average volume of a bundle of timber being hauled, m3; - number of hours of operation of the machine involved in skidding, per shift, hours; - coefficient of shift time utilization when hauling wood; - average speed of the machine involved in skidding in the idle and cargo directions along the main drags, m/s.
If there is no main road directly connecting the analyzed sections and , the element of the initial matrix is assigned the value +∞. The elements of the original matrix are assigned the value +∞.
The proposed technique is based on a sequence of transformations of the original matrix. The task is divided into smaller subtasks. The principle of dynamic programming is applied, where the optimal solution to a smaller problem can be used to solve the original problem. Moreover, according to the Floyd algorithm, at each subsequent iteration, the new matrix represents the minimum total costs for laying main trails and skidding wood between pairs of analyzed sections and with the limitation that the path between all pairs of sections and as intermediate sections contains only sections from many.
To calculate the elements of all subsequent matrices, it is recommended to use the recurrence relation:
where is the number of the analyzed matrix of values (iteration number); , - respectively, the distances between sections and , obtained from the results of matrices and , m; , - accordingly, the costs of laying the main drag line to the first nearest section on the path between sections and , obtained from the results of matrices and , i.e.
Elements , , of the last result matrix are assigned the value 0.
The results of the last iteration are substituted into the previously proposed objective function. The search for a solution can be carried out using linear programming methods.
Results of the study and their discussion. The proposed methodology for justifying the minimum costs for laying trails and skidding between all pairs of analyzed sections of the forest block makes it possible to eliminate the repeated consideration of the costs of laying main drags when analyzing the network of main drags connecting cutting areas with loading points on the territory of the forest block. In practice Using the results, it is possible to shift the loading points to a certain distance from the values indicated in the calculations, or to place timber along a temporary logging road, but it should be taken into account that moving the loading points in the direction of timber removal will lead to an increase in the costs of transport and technological development of the forest area in accordance with the following addiction:
where is the value corresponding to the change in the total costs for the development of the forest area, units; - deviation from the calculated position of the loading point in the direction of skidding (wood removal), m; - volumes of work on hauling wood from cutting sites connected by main trails to a loading point, m3; , accordingly, the cost of laying 1 running meter. main drag and 1 l.m. logging whisker.
Conclusions. The proposed mathematical dependencies and methodology make it possible to provide a comprehensive accounting of the main transport operations of skidding and removal of wood and to analyze the placement on the territory of a forest block, in addition to the block clearings that limit its perimeter, of additional temporary logging fences.
Reviewers:
Shirnin Yu.A., Doctor of Technical Sciences, Professor, Head of the Department of Human Resources, Volga Region State Technological University, Yoshkar-Ola;
Tsarev E.M., Doctor of Technical Sciences, Associate Professor, Professor, Volga Region State Technological University, Yoshkar-Ola.
Bibliographic link
Rukomoinikov K.P. GRAPHOANALYTICAL APPROACH TO JUSTIFICATION OF THE FEEDABILITY OF PLACING A TIMBER LOCKER IN THE TERRITORY OF A FOREST QUARTER // Modern problems of science and education. – 2014. – No. 6.;URL: http://science-education.ru/ru/article/view?id=16418 (access date: 02/01/2020). We bring to your attention magazines published by the publishing house "Academy of Natural Sciences"
Selection of logging routes
Proper, well-organized execution of logging work is only possible if a logging truck is brought to the cutting site in a timely manner, even before the arrival of complex teams. The direction, length and sequence of construction of the network of mustaches for the year are planned after the allocation of cutting areas. When allocating felling areas and tracing the lines, the possibility of using the existing network of lines is taken into account.
The main requirement when developing a layout for the whiskers is the requirement for the least amount of labor and money for their construction and subsequent operation, taking into account the costs of skidding. Tracing must be comprehensively linked to the technology for developing the cutting area, which is expressed in the uniform placement of loading points, reducing skidding distances, choosing a convenient location for a maintenance point, canteen, etc.
The direction of the bevel route is chosen by the technical director of the logging station together with the forest foreman, who will be entrusted with the development of this cutting area, and the road foreman, under whose leadership the bevel will be built. The route of the mustache is first outlined according to the outline, then it is specified on the ground and secured in situ with the help of poles and clippings on trees.
To lay a road strip, an 8 m wide road strip is cut. The wood that is harvested is used to build the road. The remaining logs are stacked for shipment to the lower warehouse. All dangerous trees along the logging road at a distance of 25 m in both directions must be removed before the start of its construction. The safety zone on the cutting area is cut into a strip 25 m wide by complex teams at the beginning of the development of the cutting area.
When hauling wood by car, the following types of tracks are laid: ground (rolled over natural soil), profiled, improved with the addition of sand or gravel, snow, rolled over compacted snow, and snow-irrigated; logs made of shields, logs or whips; inventory tape; prefabricated from reinforced concrete slabs; backfill on a brush bed. The type of mustache is selected depending on the soil conditions and the type of vehicles, taking into account the availability of road-building equipment and building materials in the timber industry enterprise.
Narrow-gauge roads are usually built without ballast, with a rail grid laid on a graded soil foundation. In winter, in areas with stable, long winters, mustaches are built on a snowy base.
The mustaches are built by road construction teams under the direction of a road foreman or a preparatory work foreman. The number of workers in the teams and the equipment with mechanisms is determined by special technological maps for the construction of the mustache based on local conditions and the type of the mustache. The road foreman hands over the logging roads prepared for work to the head of the road or the head of the logging station according to an act.
A temporary route for removing harvested wood from a cutting area with a service life of no more than a year, adjacent to a branch or main line of a logging road and intended for the development of individual cutting areas. Selection of routes L.u. carried out at the stage of preparatory logging work - a set of operations to create the necessary conditions for performing basic work at the cutting site. L.u. - part of the timber transport network of a logging enterprise. The distance between log stands, equal to two timber hauling distances, is established taking into account the lowest total costs for their construction and timber hauling to timber loading points. Depending on the type of terrain and the used road trains made of L. u. can be on reinforced concrete slabs, from wooden panels on a pound or sleeper base, from logs on a sleeper base (i.e., timber logging roads), as well as gravel, improved pound and pound. Use as temporary medications is not allowed. beds of rivers and streams. L.u. after the end of the removal period, the timber must be dismantled and the land occupied by them reclaimed (see Land Reclamation).
Figure 5.5. Scheme for the development of cutting areas based on feller bunchers and skidding machines: a – with tree bunching along the track of the VPM (with idling VPM); b – with packing of trees at an angle to the direction of the technological working stroke of the VPM: 1 – logging handle; 2 – main drag; 3 – bee trail; 4 – timber loading point; 5 – direction of the VPM working strokes; 6 – skidding machine; 7
– ribbon border; 8 – packs of trees, packaged by VPM; 9 – ILM; 10 – bypass drag; 11 – safety zone; 12 – planting in the cutting area before felling; 13 – preserved juveniles; 14 – seed trees
Rice. 5.6. Scheme for the development of cutting areas using three-belt technology based on feller-bunchers and skidding machines: 1 – logging bridge; 2 – main drag; 3 – apiary skidding trail; 4 – loading point, 5 – VPM technological passages; 6 – skidder; 7
– tree stumps; 8 – packs of trees laid during the development of the central belt; 9 – packs of trees laid during the development of the second belt; 10 – preserved undergrowth of coniferous species; 11 – ILM; 12 – cutting area (planting) before felling; 13 – boundary of the safety zone
The trees are trundled along a drag located on the middle belt. To ensure safe working conditions in related operations, it is advisable to simultaneously develop three adjacent apiaries. It is advisable to develop the right belts after the trees from the middle and left belts have been shot. Trees are skidded with their tops forward using tractors with manipulators or with rope-choker equipment.
The main disadvantage of the scheme (Fig. 5.6) is the multiple passes on the drag (24...30 runs) of the skidding machine and the possibility of damage to the soil on it and idle runs of the VPM, which negatively affects its performance. Therefore, it is preferable to develop the cutting area using two-belt technology.
The development of an apiary using the two-belt method is carried out in two steps, starting with the right belt in a similar way to the three-belt technology, in this case meaning the right belt as the middle one. The development of the left ribbons is identical. The advantage of this scheme is that it can be applied
to be used in cutting areas and with satisfactory bearing capacity of the soil, as well as greater productivity of the VPM compared to the development of a three-belt apiary.
The scheme for carrying out inter-strip gradual felling using the two-belt technology is shown in Fig. 5.7. When developing a central belt, in the middle of which a skidding trail is laid, packs of trees are placed strictly in the wake of the machine; when developing an adjacent strip - at an angle of up to 30° to the direction of the draw. Then the VPM moves to another apiary, leaving one or two apiaries of length (n − 1)l n untouched, where n is the number of cutting techniques. After moving to
In the second apiary, in the first, the trees are cleared of branches with a light chainsaw. The collection and skidding of the logs by the top is carried out by a tractor with a manipulator or with rope-choker equipment. This allows you to preserve your teenage years.
Rice. 5.7. Scheme for the development of cutting areas when carrying out inter-strip gradual felling using two-belt technology: 1 – logging strip; 2 – timber loading point; 3 – drag; 4 – skidder; 5 – preserved undergrowth of coniferous species; 6 – stumps; 7 – technological progress of the VPM; 8 – preserved forest strip; 9 – limber; 10 – ILM; 11 – packs
trees laid on a drag when developing the central belt
Technologies for developing cutting areas based on feller-bunchers and
skidding machines with VPM technological passages parallel to the logging bridge or circular acceptable for sale exclusively
only clear cuttings with subsequent reforestation under certain natural conditions.
Rice. 5.8. Scheme for the development of VPM cutting areas and skidding machines: a – with stacking of trees at an angle close to straight to the direction of the technological progress of the VPM; b – ring diagram: 1 – timber hauler; 2 – timber loading point; 3 – stack of whips; 4 – skidder; 5 – stumps; 6 – boundary of the safety zone; 7 – ILM; 8 – direction of the technological progress of the VPM; 9 – seed trees; 10 – packs of trees harvested by VPM; 11 – border of ribbons; 12 – growing forest
Development of the plot with passages parallel to the logging bridge (Fig. 5.8, a) allows you to create a stock of bundles on the plot, which has to be done when there is a technological gap between the felling and the skidding. It is advisable to use it in flat cutting areas with soils of increased bearing capacity. The development of the plot begins from the far edge with straight moves parallel to the mustache with UPM turns at the ends of the belts. As the strips are cut, the feller buncher approaches the timber hauling machine. Bundles of trees are laid perpendicular to the direction of movement of the machine, with their butts facing the logging fence. On the first two or three belts, the packs are laid at smaller angles.
Skidding of bundles begins after the development of the entire plot of land without the installation of drags along the shortest distance from the place where the bundles of trees are laid to the loading point across the developed belts.
When moving in a circle (Fig. 5.8, b), the VPM begins to develop the plot, moving along the ribbons at its boundaries, gradually approaching the center as the plot is developed. The VPM places the trees being cut at an angle behind or in front of itself, depending on the direction of skidding. The large scope of work created makes it possible to ensure skidding of bundles from any place, excluding the safety zone near the VPM.
When working in a circular pattern, HPPM turns are minimized, and thereby the loss of time for maneuvering is reduced. If the width and parallelism of the belts are strictly maintained and the packs are laid at the rear along the axis of movement of the machine, the VPM can work with partial preservation of the undergrowth. In this case, all belts are developed by machine moves only in the skidding direction. The scheme (Fig. 5.8, b) is recommended when the VPM operates on moist soils or if there are non-operational areas within the massif, as well as open forests and swamps.
5.3. Technologies for developing cutting areas with tree skidding based on feller skidders
The technology for developing cutting areas depends on the operating mode of the feller-skidder (VTM), the terrain and soil conditions. VTM can operate in technological modes: roller-skidding and roller-bunching.
Technologies for the development of VTM cutting areas using parallel passages along the felled strips of the tree stand acceptable for the implementation of clear cuttings with subsequent renewal, as well as the first methods of inter-strip gradual felling in plantations without undergrowth. During development
cutting areas according to the schemes (Fig. 5.9, a, b) the installation of apiary trails is not provided.
The scheme for developing plots with belts perpendicular to the logging fence (Fig. 5.9, a) is the main technological scheme. It is used in non-swampy areas of the cutting area with flat terrain or gentle slopes towards the logging fence.
Rice. 5.9. Schemes for the development of cutting areas using felling and skidding machines when operating in the felling and skidding mode: a – with belts perpendicular to the logging trail; b – belts parallel to the timber hauler: 1 – timber hauler; 2 – tapes; 3 – VTM; 4 – stumps; 5 – growing forest; 6 – technological moves of the machine; 7 – safety zone; 8 – skidding drag; 9 – timber loading point, 10 – drive-through portage; – width of the developed
Development of the main part of the plot begins with cutting the first strip. To do this, the VTM, maneuvering between the trees, moves from the grove deep into the plot to a distance that ensures the formation of the maximum permissible pack of trees, after which the machine turns around and, moving towards the grove, cuts off the trees on the left side and forms a pack of them, which it then clears to the timber loading point located near the mustache. This technique is repeated until the tape is cut to the end of the plot. Having completed the development of the first tape, VTM begins to develop the next tape from its far end. Moving along the forest wall, the machine cuts and lays
The conic attacks all trees located in the zone of action of the working bodies of the TMV to the left of it. Having formed a pack of trees, the VTM transports it to the timber loading point. Then the machine returns to the belt being developed, where the last tree was felled, picks up the next pack and skids it. This continues until the tape is fully developed. All subsequent strips on the plot are developed in the same order.
When working according to the scheme (Fig. 5.9, a), the width of the plot a d should be
such that the machine can form at least one pack. This is possible if
where l p is the length of the tape for collecting one pack, m; V p – volume of the formed pack, m3; q – reserve per 1 ha, m3/ha; bл – width of the tape on which the bundle is formed, m; and without - the width of the safety zone along the timber haulage.
The scheme for developing a plot with strips parallel to the logging fence (Fig. 5.9, b) is used for the development of cutting areas with flat terrain with low labor intensity for laying logging tracks. On dense soils and in winter, the logging fence can move following the development of the plot, which reduces the average skidding distance to a minimum. The mustaches can be laid across distances within 60...100 m. The plot is developed by VTM passages parallel to the longitudinal side of the forest and the mustache. The technology for developing tapes and the sequence of their development are similar to the previously described process. The formed pack of trees on the belt is transported to the timber loading point along the shortest path across the previously developed belts.
In the case of moist soils in summer or with deep snow cover in winter, it is better to develop the plot with strips located at an angle of 60...70° to the logging fence. This arrangement of the belts facilitates the movement of the VTM in the cargo direction by reducing the angle of rotation when leaving the timber loading point.
Narrow apiary technology based on feller-skidding machines with tree skidding by the butt acceptable for the implementation of predominantly clear-cutting with preliminary regeneration (preservation of undergrowth), as well as inter-strip cutting in areas with and without undergrowth, clear-cutting with subsequent reforestation.
Using this technology, it is possible to develop cutting areas while preserving 40...60% of the undergrowth. To do this, skidding dies are marked on the plots with a distance between them within 1.5...2 maximum working radii of the Rmax manipulator (Fig. 5.10).
After felling and skidding of the forest from the safety zone, the forest is sequentially cut down on a trail up to 4 m wide, and then developed
the top of both half apiaries. The cutting of the drags is carried out by the VTM, usually when moving in reverse along the intended target.
Fig.5.10. Scheme for the development of cutting areas using narrow apiary technology based on felling and skidding machines with the preservation of undergrowth: 1 – skidding trail; 2 – timber hauler; 3 – boundary of the safety zone; 4 – bee trail; 5 – timber loading point; 6 – trees cut down during the development of the drag; 7 – VTM; 8 – border of apiaries; 9 – preserved undergrowth; 10 – sources of contamination; 11 – growing forest
Moving in the opposite direction, the VTM cuts down and places trees in a conic located both on the left and on the right along the direction of its movement within the radius of action of the manipulator. Trees that are more distant from the trail are felled, top to top, of trees laid in a bunk, and the butts are placed in a bunk using a manipulator, which eliminates damage to the undergrowth. At the same time, trees felled during the cutting of the trail are selected. The formed bundle is transported to the timber loading point. After skidding, the next pack of TMV returns back to the apiary drag and the cycle repeats. After the entire tape has been developed, the machine moves on to the next tape.
Technology for developing the VTM cutting area in felling mode
baling and skidding of tree packs using skidding machines along specially cut trails acceptable for the implementation of clear cuttings with subsequent renewal, as well as the first methods of inter-strip gradual felling in plantations without undergrowth.
When operating in the felling-bunching mode, the VTM must form bundles, the volume of which would correspond to the trip load for a skidder operating in combination, usually with a bundle gripper. The formation of a bundle to suit the traction characteristics of a skidder is a distinctive feature of the VTM operation in the felling-bunching mode.
The operation diagram of the VTM in the felling-bunching mode is shown in Fig. 5.11. Here, a skidding machine works in tandem with the VTM. TMV moves along the cutting area along a two-way expanding perimeter. The processed belts are located parallel to the logging road. The felled trees are placed in a forming device and, as the bundle is formed, they are unloaded at the main drag. Their skidding into stacks is carried out by a skidding machine, which in this case does not leave the main drag. Before starting work according to this scheme, the main trails must be cut, as well as a technological corridor in the middle of the cutting area parallel to the logging road.
When developing a plot with moves parallel to the logging fence, the length of the pack formation belt can be determined by the formula:
qbl |
|||||||
where V – |
volume of the formed pack, m3; q – forest reserve per 1 hectare, m3; b |
||||||
belt width developed by VTM in one pass, m.
Depending on the type of timber being exported, technologies for developing cutting areas using feller bunchers and feller skidders (Fig. 5.5...5.11) can be implemented in variants of work at a timber loading point: with loading and removal of trees; with clearing trees from branches and loading and removing tree trunks; with cleaning trees from branches, bucking logs into logs, loading and hauling logs.
Rice. 5.11. Scheme of development of logging areas along the VTM in the windrow bunching mode: 1 – logging bridge; 2 – timber loading point; 3 – growing forest; 4 – stumps; 5 – main drag; 6 – tapes; 7 – boundary of the safety zone; 10 – VTM; 8 – skidder; 9 – technological moves of the machine; 11 – technological corridor for vehicle entry; 12 – packs of trees
5.4. Technologies for developing cutting areas based on harvester and forwarder
Narrow apiary technology for developing cutting areas based on a harvester and forwarder acceptable for the implementation of all types of clear cuttings, including with preliminary renewal, mainly in plantations with small undergrowth and with low- and medium-productive tree stands, selective cuttings (alternate, evenly gradual, etc.) when fulfilling silvicultural requirements for limiting the area of trails by giving they have a tortuous shape, including when cutting in winter without restrictions, in summer, excluding waterlogged soils.
The development of cutting areas using harvesters involves the use of two possible methods of storing logs relative to the direction of movement of the machine: one-way and two-way. The double-sided method of laying logs allows you to reduce the amount of work involved in dragging trees when performing technological
FORESTRY ENGINEERING
PLACEMENT OF A LOGGING CARRIER AT A LOGGING AREA
D.N. AFONCHEV, associate professor department forest transport and engineering geodesy VGLTA, Doctor of Engineering. sciences
There are various options for placing a logging fence in a cutting area, the most common are two schemes: laying a fence in the middle and along the edge of a cutting area, but the conditions under which the fence should be placed in the middle and along the edge of a cutting area are not substantiated. Obviously, the placement of the fence is determined by the width of the cutting area: with a relatively small width, it is advisable to place the fence along the edge of the cutting area from the side of the logging highway. The choice of a specific option for placing a fence at a cutting site can be justified by comparing the costs of constructing skidding roads, loading points and skidding of timber to loading points for the options under consideration.
Let us denote the total costs for the construction of skidding roads, loading points and skidding of timber to loading points when placing the fence along the edge of the cutting area Z1 (rub), and when placing the fence in the middle of the cutting area - Z2 (ruble). Placing a mustache along the edge of the cutting area is advisable if the condition is met
If condition (1) is not met, the fence must be placed in the middle of the cutting area.
Each of the parameters Zx and Z2 includes five cost items: Z3 - costs for setting up loading points, rubles; Z4 - costs for the construction of main skidding roads, rubles; Z5 - costs of skidding along main drags, rubles; Z6 - costs of installing bee trails, rubles; Z7 - skidding costs along apiary trails, rub. Costs Z3, Z4, Z5, Z6, Z7 are determined taking into account the size of the cutting area, apiaries, the location of loading points and the parameters of the technological process of logging operations. By means of algebraic constructions, it is possible to obtain analytical dependencies that determine the indicated costs
where m is the number of loading points located on one side of the mustache; k is the number of rows of apiaries in the cutting area;
K is the cost of setting up one loading point, rub.
The number of rows of apiaries k depends on the placement of the fence; when the fence is located in the middle, k = 2, and when the fence is located along the edge of the cutting area, k = 1.
Z4 = mkC1kPT(lII + a - a0), (3)
where CT is the cost of installing a main drag line, rub/km;
kPT - main drag elongation coefficient;
1п - distance between loading points, km;
a is the length of the main drag within the loading point, km;
a0 is the half-width of the zone of gravity towards the apiary trail, km.
Z5 = 1шЯГГ (4)
where 1Ш is the average skidding distance along the main drag, km;
q is the volume of wood being hauled, m3;
Ът - cost of hauling wood along the main drags, rubles/(m3-km).
7 - mkkpnlnCn (dy z^ (5)
7 - 2ao It - J- (5)
where kpn is the elongation coefficient of the apiary drag;
SP - the cost of installing an apiary trail, rubles/km;
dy is the width of the zone of gravity towards the yoke, km;
z is the distance from the road to the main drag, km.
where lmB is the average skidding distance along the main drag, km;
Ъп - cost of hauling wood along apiary trails, rub/(m3-km).
If we assume that the cutting area is rectangular in plan, then the volume of wood harvested at the cutting area q can be determined by the formula
q = X.00^^^., (7)
where y is the liquid wood supply per 1 hectare, m3/ha.
FOREST BULLETIN 3/2009
FORESTRY ENGINEERING
The average skidding distances along the main and apiary drags when the apiary drags are placed perpendicular to the logging trail, and the main trails are placed parallel to the trail are
lMB = kPT;
Pv = 0.5kPn((dy / k) - z) (8)
The total costs Zx at k = 1 will be
Zj = mK + mC1kPT(ln + a - a0) +
100Ydylnmb1kpT +
+ (mkPnlnCn / 2a0)(dy - z) +
50Jdylnmkpnbn(dy - z). (9)
The total costs Z2 at k = 2 will be
Z2 = 2mK + 2mCTkPT(ln + a - a0) +
100Ydylnmb1kPT +
+ (mkPnInCn / 2a0)(dy - 2z) +
25JdylnmkPnbn(dy - 2z). (10)
Inequality (1) is easy to lead to
Z2 - Zj > 0. (11)
Taking into account formulas (9) and (10), after transformations inequality (11) takes the form
mK + mCTkPT(ln + a - a0) - zmkPn ln CJ2a0 -
25YlnmkPnbn Cpy> °. (12)
Since m > 0 and a0 > 0, both sides of inequality (12) can be divided by m and multiplied by a0 without changing the sign
2a0K + 2a0C1kPT(ln + a - a0) -
ZkPn lnCn - 50a0YlnkPnbndy2 > 0. (13)
The resulting inequality can easily be solved with respect to dy
dy< (2a0K + 2a0CTkPT(ln + a - a0) -
ZkPn lnCn) / 50a0YlnkPnbn. (14)
The width of the zone of gravity towards the whisker dy is a positive value, and therefore the square root can be extracted from both sides of inequality (14) without changing the sign of the inequality
2a0K + 2a0CTkPT x
x(ln + a - a0) - zkpnlnCn (15)
Formula (15) can be simplified by replacing an = 2a0 (an is the width of the zone of gravity towards the apiary trail, km) and removing the numerical constant from under the root, then placing the mustache along the edge of the cutting area is advisable if the condition is met
a^K + anCTkpT x x(ln + a - 0.5an) - zkpnlnCn
From the resulting expression (16) it is clear that the placement of the whisker is influenced by three groups of factors: technological parameters (an, ln, a, z), economic indicators (K, CT, Cn, bn) and natural conditions (kPT, kPn, y) . Let us study the influence of the apiary width ln and the liquid supply of wood y on the width of the zone of gravity towards the bevel dyK, at which Zj = Z2, and therefore according to formulas (11) - (16)
a^K + anCTkpT x x(ln + a - 0.5an) - zkpnlnCn an ylnkpnbn
It should be taken into account that ln = nan, where n is an integer, then formula (17) is transformed to the form
K + CTkpT -
NzkpnCn nanYkpnbn
Let us accept the following values in accordance with: K = 35 rubles, CT = 30 rubles/km, Cn = 10 rubles/km, bn = 0.55 rubles/(m3-km) (economic indicators are taken at the basic level), an = 0.016 km, a = 0.03 km, z = 0.05 km. For flat terrain, kPT = 1.15, kPn = 1.2 can be taken. Liquid wood stock
Let us take Y in the range of 50-250 m3/ha with a change step of 50 m3/ha, with small values
Y correspond to cutting areas when carrying out maintenance felling. The distance between loading points ln can vary in a fairly wide range, and therefore we will take the value n = ln / an in the range from 1 to 12.
The figure shows graphs of the dependence dyK = fly). The set of dy values located above the curved graphs shown in the figure, according to (16), corresponds to the condition of placing the whisker in the middle of the cutting area, and, accordingly, the set of dy values located below the curved graphs corresponds to the condition of placing the whisker along the edge of the cutting area.
FOREST BULLETIN 3/2009
