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Construction machines and equipment. Methods of soil development Transverse moves during soil development

2.1. Before constructing a half-cut-half-fill subgrade (Fig. 1), it is necessary to:

· · restore and secure the road route;

· · break and secure the right-of-way;

· · clear the area within the right-of-way and quarries from bushes, stumps and large stones;

· · break the roadbed;

· · arrange temporary drainage.

2.2. Work on the construction of the roadbed is carried out in the developed technological sequence (Table 2) using the in-line method on two grips 125 m long and on a third grip 300 m long during the final work (Fig. 4).

2.3. On the first takeover

cutting off the vegetation layer of soil within the slope with a DZ-171 bulldozer;

construction of a mountain ditch using a universal earth-moving and leveling machine - excavator-leveler EO-3533.

A bulldozer is used to cut and remove plant soil in a shuttle pattern, starting from the top of the slope, moving it down, beyond the right-of-way, and placing it in a dump for subsequent use. The thickness of the plant soil layer in the technological map is assumed to be 20 cm.

Rice. 1 . Cross profile half-cut subgrade-half-embankment

The upland ditch is being developed using an EO-3533 leveling excavator with a bucket with a capacity of 0.5 m 3 . The excavator is installed on a “shelf” specially arranged on a slope. When developing a ditch, the excavator moves along the axis of the road. The design depth of the ditch is indicated on the pegs that secure the position of its axis.

The development of the profile of an upland ditch (Fig. 2) is carried out in the following sequence: with a bucket installed at the angle of the slope, the soil is cut along the contour of one slope, and then along the contour of the other slope; the soil remaining along the axis of the ditch is removed with a normally installed bucket and the bottom is cleaned. The excavated soil is poured into a bank on the downstream side of the upland ditch.

Rice. 2 . Scheme of developing a profile of a mountain ditch using an excavator-EO planner-3533 :

1 - 3 - soil excavation sequence

If necessary, the leveling of the soil in the banquet is carried out with the blade of the EO-3533 excavator during the second excavation.

2.4. On the second takeover The following technological operations are performed:

· · cutting ledges with a bulldozer;

· · development of soil in a excavation and moving it into an embankment with a bulldozer;

· · layer-by-layer leveling of soil with a bulldozer;

· · moistening the compacted soil layer with water using a watering machine (if necessary);

· · layer-by-layer compaction of the embankment with a self-propelled roller on pneumatic tires.

The ledges are cut with a bulldozer with a T-4AP2 OBGN-4M rotary blade in sections 60 - 70 m long. The lower ledge is cut wider than the ledges arranged above (up to 6 m wide). The next one is cut by a bulldozer moving along an embankment poured to the height of the first ledge, etc. (Fig. 3).

Rice. 3 . Cutting benches with a bulldozer with a rotary blade:

1 - ledge; 2 - poured layers of embankment

The width of the ledge can be 2 - 4 m, the height - 0.5 - 2.0 m. The top of the ledges at the base of the embankment is given a transverse slope towards the road axis of 0.01 - 0.02, the walls of the ledges at a height of up to 1 m are made vertical, and at a height of up to 2 m - with a slope of 1:0.5.

The half-excavation is developed using a bulldozer with a rotary blade. The development of the soil begins from its upper part, arranging a platform at least 3 m wide (Fig. 5). Then the soil is cut off in layers 0.3 - 0.4 m thick and moved along the slope to a distance of 10 m.

Rice. 4 . Technological plan flow for the construction of semi-dug-type subgrade-half-embankment

The cut soil is moved down the slope by a bulldozer with a fixed blade DZ-171 to a constructed ledge. Then the soil is moved by a bulldozer along the ledge at a distance of up to 20 m, leveling it in layers of 0.3 - 0.4 m.

Rice. 5 . The sequence of developing a half-excavation on a slope

After filling the first layer in a 30 m area, compaction begins. Bulldozers continue to fill the first layer of the embankment using the above technology in the next section of the same length.

After filling the layer in the second section, the bulldozers return to the first and carry out work on filling the next layer over the previously compacted one.

The development of soil on the slope and the filling of subsequent layers are carried out in a similar sequence.

It is planned to fill the embankment 0.5 m wider than the design outline based on the conditions of soil compaction in the edge parts. Excess soil is removed when leveling slopes.

Compaction of the filled layer is carried out with a self-propelled roller on DU-101 pneumatic tires in ten passes along one track using a shuttle pattern. Compaction should begin at a distance of at least 1.5 - 2.0 m from the edge of the embankment and gradually approach the slope with each subsequent pass. In this case, it is not allowed for the edge of the compacting body of the roller to approach the edge of the embankment closer than 0.3 m. After this, rolling continues from the edge to the middle of the embankment, overlapping the previous track by 1/3 of the width.

Table 1

Elements of the subgrade	Layer depth from the coating surface, m	Lowest soil compaction coefficient for the type of road pavement
capital	lightweight and transitional
in road climate zones
I	II, III	IV, V	I	II, III	IV, V
Working layer	Up to 1.5	0,98 - 0,96	1,0 - 0,98	0,98 - 0,95	0,95 - 0,93	0,98 - 0,95	0,95
Non-floodable part of the embankment	St. 1.5 to 6 St. 6	0,95 - 0,93 0,95	0,95 0,98	0,95 0,95	0,93 0,93	0,95 0,95	0,90 0,90
Floodable part of the embankment	St. 1.5 to 6 St. 6	0,96 - 0,95 0,96	0,98 - 0,95 0,98	0,95 0,98	0,95 - 0,93 0,95	0,95 0,95	0,95 0,95
In the working layer of the excavation below the seasonal freezing zone	Up to 1.2 Up to 0.8	- -	0,95 -	- 0,95 - 0,92	- -	0,95 - 0,92 -	- 0,90

The pneumatic roller performs the first and last passes along the rolling strip at a speed of 2.0 - 2.5 km/h, intermediate passes - 5 - 8 km/h.

The pressure in the tires of the roller should be the same and be: for cohesive soils at the beginning of compaction - 0.2 - 0.3 MPa; at the final stage for sandy loam - 0.3 - 0.4 MPa, for loams and clays 0.6 - 0.8 MPa; for sands at all stages of compaction - 0.2 - 0.3 MPa.

The density of the soil after rolling the layer must correspond established requirements regulatory documents. In this case, the soil compaction coefficient, depending on the design depth of the layer from the pavement surface, must meet the requirements given in Table. 1.

The soil should not be over-moistened, and in the event of intense rains, the construction of an embankment from clay soils should be suspended. Before a long break in work, it is necessary to ensure drainage from the surface of the unfinished embankment.

Dry and slightly moist soils should be moistened with the MD-433-03 watering machine adopted in the map. The layer of compacted soil must be completely saturated with water. The technological map provides for water consumption equal to 3% of the mass of soil poured into the embankment.

2.5. On the third takeover The following technological operations are performed:

· · cutting off excess soil from the embankment slope and leveling the surface of the embankment slope using a leveling excavator;

· · surface planning of the semi-excavation slope using a motor grader;

· · leveling the top of the roadbed using a motor grader;

· · cutting a ditch with a motor grader;

· · final compaction of the top of the subgrade with a pneumatic roller.

Cutting off excess soil from embankment slopes and leveling the surface of the embankment slope is carried out by an EO-3533 excavator-leveler.

Before cutting soil from a slope, the upper platform of the embankment must be leveled, and the edge must be marked with pegs every 20 m.

The soil cut from the slope is used in powdered shoulders.

To ensure the design position of the slope, immediately after cutting the soil, slopes are installed every 50 m and edge lines are marked.

The semi-excavation slope surface is leveled using a DZ-122 motor grader.

The leveling of the top of the roadbed is also carried out using a DZ-122 motor grader in four passes along one track using a shuttle pattern.

Before starting planning, it is necessary to check and restore the position of the axis and edges of the subgrade in plan on straight lines, transitional and main curves, as well as in the longitudinal profile.

The leveling begins from the lowest areas (in the longitudinal profile), leveling the top of the embankment through successive passes of the motor grader, starting from the edges with a gradual shift to the middle. The overlap of the previous track is 0.3 - 0.5 m. The grip angle of the motor grader blade is set to 45 - 55° towards the road axis.

The ditch is cut using a DZ-122 motor grader while moving along the roadbed, strictly ensuring compliance with the design slope. The cutting angle should be within 35 - 45°.

The final compaction of the top of the roadbed is carried out with a self-propelled pneumatic roller DU-101 in four passes along one track, in a circular pattern with tracks overlapping by 1/3. The required pressure in the tires of the pneumatic roller is indicated in paragraph 2.4.

The technological sequence of processes with calculation of the volume of work and required resources is given in table. 2, the composition of the detachment is in table. 3.

The technological flow plan for the half-cut-half-fill device is shown in Fig. 4. The technology for operational quality control of work during the installation of half-excavation-half-fill is given in table. 4.

Table 2

Technological sequence of processes with calculation of volumes of work and required resources

No. of processes	No. of grips	Source of justification for production standards (ENiR and calculations)	Description of work processes in the order of their technological sequence with calculation of work volumes	Unit of measurement	Number of works	Productivity per shift	Demand for machine shifts	Labor costs and wages for a gripper 125 m long
per grip l = 125 m	by 1 km	per grip l = 125 m	by 1 km	Standard time, person-hour	Wages, rub.-kop.
per unit of measurement	for the full scope of work	per unit of measurement	for the full scope of work

I. Main excavation work (coverage l = 125 m)
	I	Calculation	Cutting and removing a 0.2 m thick plant layer of soil with a DZ-171 bulldozer within the slope in the amount of: 36·125 = 4500	m 2				1,05	8,4	0,00187	8,41	0-04	180-00
	I	Calculation	Construction of an upland ditch using a leveling excavator EO-3533 with soil unloading into a banquet: (2.85 + 0.6) 0.75 125/2 = 162	m 3				0,90	7,19	0,044	7,13	0-94,4	152-93
	II	Calculation	Cutting benches and moving soil with a T-4AP2 OBGN-4M bulldozer at a distance of 30 m: 227 3 = 680	m 3				0,9	7,25	0,011	7,48	0-24	163-20
	II	Calculation	Development of a half-excavation and movement of soil into a half-embankment with a D3-171 bulldozer at 10 m: 211 + 461 + 711 = 1383	m 3				0,70	5,67	0,0041	5,67	0-08,8	121-70
	II	Calculation	Transverse movement of previously developed soil from an excavation and longitudinal movement along a ledge using a T-4AP2 OBGN-4M bulldozer at a distance of 20 m: 211 + 461 + 711 = 1383	m 3				1,11	8,85	0,0064	8,85	0-13,7
	II	Calculation	Layer-by-layer leveling of soil in an embankment 0.35 m thick with a T-4AP2 OBGN-4M bulldozer: 438 + 688 + 938 = 2064	m 3				0,70	5,58	0,0027	5,57	0-05,8	119-71
	II	Calculation	Layer-by-layer rolling of soil in an embankment when developing ledges and excavations with a self-propelled roller DU-101 on pneumatic tires in 4 passes along one track: 750 + 1562 = 2312	m 3				0,38	3,00	0,0013	3,0	0-02,8	64-74
		Calculation	Layer-by-layer moistening of the soil with water to optimal humidity using a watering machine MD 433-03 with a hauling distance of 3 km in an amount of 3% of the mass of the soil with a density of 1.75 t/m 3: (438 + 688 + 938) 1.75 0, 03 = 110	m 3	BY			1,62	12,94	0,079	8,69	1-47	161-70
	II	Calculation	Layer-by-layer compaction of soil in an embankment 0.3 m thick in a dense body with a self-propelled roller DU-101 on pneumatic tires with 10 passes along one track: 438 + 688 + 938 = 2064	m 3				1,73	13,82	0,0067	13,83	0-14,4	297-22
			TOTAL:								68,63		1450-67
II. Final excavation work (coverage l = 300 m)
	III	Calculation	Layout of excavation slopes using a motor grader DZ-122 during a working stroke in two directions: 5.9 300 = 1770	m 2				0,19	0,63	0,00085	1,50	0-01,8	31-86
	III	Calculation	Layout of the top of the roadbed using a DZ-122 motor grader in four passes along one track: 14.2 300 = 4260	m 2				0,47	1,56	0,00088	3,75	0-01,9	80-94
	III	Calculation	Final compaction of the top of the roadbed with a self-propelled roller DU-101 on pneumatic tires in 4 passes along one track: 12 300 = 3600	m 2				0,36	1,19	0,0079	2,84	0-01,7	61-20
	III	Calculation	Cutting off excess soil from an embankment slope and leveling the slope using an EO-3533 leveling excavator equipped with a leveling bucket: 6.7 0.22 300 = 442	m 3				0,78	2,59	0,014	6,19	0-30	132-60
	III	Calculation	Construction of a ditch using a motor grader DZ-122: (2.2 + 0.4)/2 0.4 300 = 156	m 3				0,27	0,91	0,014	2,18	0-30	46-80
			TOTAL:								16,46		353-40

Table 3

Squad composition

Cars	Profession and rank of worker	Demand for machine shifts	Need for cars	Load factor	Number of workers
at 1000 m	for capture
1. Basic excavation work (coverage 125 m)
Bulldozer DZ-171	Driver VI category	14,07	1,75		0,88
	Driver VI category	7,19	0,9		0,90
Bulldozer T-4AP2 OBGN-4M	Driver VI category	21,68	2,7		0,90
	Driver VI category	16,82	2,11		0,70
Watering machine MD 433-03	Driver VI category	12,94	1,62		0,81
2. Final excavation work (coverage 300 m)
Motor grader DZ-122	Driver VI category	3,1	0,93		0,93
Excavator-planner EO-3533	Driver VI category	2,59	0,78		0,79
Self-propelled roller on pneumatic tires DU-101	Driver VI category	1,19	0,36
Note: Self-propelled rollers DU-101 on pneumatic tires in the amount of 3 pieces are used in the main and final excavation work.

Table 4

Technology of operational quality control of work during the construction of a 3 m high subgrade of the half-cut-half-fill type

Basic operations subject to control	Composition of control	Method and means of control	Mode and scope of control	Person exercising control	Limit deviations from the norms of controlled parameters	Where are the control results recorded?

Removing the plant layer of soil	Thickness of the removed soil layer	Instrumental		Master	±20% of design thickness	General Journal works
Construction of an upland ditch		Instrumental Measuring tape	Measurements at least every 100 m	Master	±5 cm from design values	General work log
2. Depth of the upland ditch	Instrumental Level	Measurements at least every 100 m	Surveyor	±5 cm from design values
Layer-by-layer leveling of soil in the embankment	1. Thickness of the leveled layer	Instrumental Measuring ruler, sights	Measurements at least every 100 m	Master	±20% of design thickness	General work log
2. Soil uniformity	Visual	Constantly	Master, laboratory assistant	-	Subgrade acceptance sheet
Layer-by-layer compaction of the embankment	1. Density of the subgrade soil	Laboratory Cutting ring method Accelerated and field express methods and devices	At least every 200 m with an embankment height of up to 3 m (at least 3 points: along the axis of the subgrade and at a distance of 1.5 - 2.0 m from the edge)	Laboratory assistant	Reduction in soil density by no more than 4% from design values to 10% of definitions
2. Humidity of compacted soil	Laboratory Sampling of soil in bottles	At least once per shift (at least three samples) and always during precipitation Note: p.p. 1, 2 can be performed together	Laboratory assistant	Table 1. SNiP 3.06.03-85	Laboratory control log
3. Compaction mode and technology	Visual	Constantly	Master	General work log
Layout of embankment and excavation slopes	Slope steepness	Inclinometer	Measurements after 50 m	Master	Reducing the slope to 10% of the design value	General work log
Layout of the top of the subgrade	1. Elevations of the longitudinal profile	Instrumental Level	Measurements at least every 100 m	Surveyor	±50 mm from design marks	Technical leveling magazine
2. Distance between the axis and the edge of the roadbed	Instrumental Measuring tape	Measurements at least every 100 m	Master	±10 cm from design values	General work log
3. Cross slopes	Instrumental Inclinometer	Measurements at least every 100 m	Master, surveyor	±0.010 from design values	Subgrade acceptance sheet
Cuvette device	1. Transverse dimensions of the upland ditch (along the bottom)	Instrumental Measuring tape	Measurements at least every 100 m	Master	±5 cm from design values	General work log
2. Depth of the upland ditch	Instrumental Level	Measurements at least every 100 m	Surveyor	± 5 cm from design values	Technical leveling magazine

OCCUPATIONAL SAFETY

Persons who have reached the age of 18, have a certificate for the right to drive this machine and are aware of the requirements for safe work are allowed to drive road vehicles.

When working on the construction of embankments of the roadbed with bulldozers, it is prohibited:

· · carry out excavation work until the site is cleared of forest, stumps, boulders and the boundaries of the right-of-way are demarcated;

· · excavate the soil with a bulldozer at a distance closer than 1 m from the location of underground utilities;

· · produce without permission (disruption warrant) from the organizations operating these communications;

· · move soil up or down a slope of more than 30°;

· · rotate the bulldozer with a loaded or buried blade;

· · work in clayey soils in rainy weather;

· · be on the ripper frame when the teeth are lowered into the ground and during their lifting.

To avoid collapse of the soil (sliding of the embankment) and overturning of the bulldozer when pushing soil under the slope of the embankment or backfilling trenches, the bulldozer blade does not extend beyond the edge of the slope, and when constructing an embankment, the distance from the edge of the caterpillar or bulldozer wheel to the edge of the embankment must be at least 1 m. When When carrying out work on constructing the roadbed with a bulldozer, we are guided by the following technical literature:

1. SNiP III-4-80. Safety precautions in construction.

2. SNiP 12-03-2001. Occupational safety in construction. Part 1. General requirements.

3. TOI R-218-05-93. Standard instructions on labor protection for the operator of a motor grader (trailer grader).

4. TOI R-218-07-93. Standard labor safety instructions for the roller operator.

5. TOI R-218-26-94. Standard labor safety instructions for the operator of a watering machine.

6. TOI R-218-06-93. Standard labor safety instructions for a bulldozer operator.

7. Spelman E.P. Safety precautions when operating construction machines and small-scale mechanization equipment. - M.: Stroyizdat, 1986. - 271 p.: ill.

Technological map No. 7

Bulldozers perform operations as follows. Layer-by-layer development and movement of materials produced at a transportation distance of 50... 150 m. Long distances of movement are economically beneficial for heavy bulldozers. During surface mining of soils and minerals, the machine is characterized by shuttle movements, alternating the working stroke and moving back empty. It is advisable to collect and transport soil in one pass with the formation of side rollers, the trench method, the paired operation of bulldozers, and the formation of several prisms. In light ground conditions, additional replaceable bulldozer equipment (openers, extensions, extensions) is used.

Construction of embankments carried out in two ways: transverse passages from the reserve and longitudinal one-way movements of the machine.

When transversely moving soil from reserves, it is advisable to use the trench method of developing materials and the paired operation of several machines. The first prisms are applied to the center of the embankment, the subsequent ones - closer to its edges.

The drawing prisms are placed pressed together. The rise of the embankment slopes along which soil is supplied should not exceed 30%. With large elevations of the embankment, the work is ineffective.

Rice. 137. Basic excavation bulldozer work.

See also:

By longitudinal movements of the bulldozer in the direction of the longitudinal axis of the embankment, it is advisable to feed the soil downhill. The height of the embankment in this case can be up to 4...5 m.

Development of excavations produced by longitudinal bilateral passes and transverse passes . The longitudinal two-way method provides greater productivity of bulldozers. It is used for small excavations and in cases where the soil removed from the excavation is completely laid in adjacent embankments. The transverse excavation method is used when excess soil is placed in cavaliers along the future road surface.

Excavation of canals, irrigation structures, trenches, pits produced by transverse moves of a bulldozer with a gradual displacement of the machine along the structures . The soil is placed in cavaliers along the entire length of the canals, creating earth banks on both sides. The soil is excavated in parallel trenches with a depth no greater than the overall height of the machine. The distance between the trenches is up to 0.4...0.6 m. After the separation, the intertrench jumper is destroyed. In this case, group operation of machines with paired parallel moves is effective.

Planning work carried out on a flat surface, cutting off small mounds and filling in depressions, holes, and ravines. Large depressions are filled up from neighboring slopes with longitudinal passages . The last passes are made with an offset of V4 of the blade width to prevent the appearance of side rollers. After rough front leveling, it is advisable to finish the surface with the bulldozer moving in reverse and the blade in a “floating” position. For greater accuracy, it is advisable to use mutually perpendicular passages of bulldozers.

Punching terraces and shelves on slopes carried out by bulldozers with fixed and rotary blades. The most effective and safe way to move soil from a slope to a half-embankment is by transverse passes of the machine downhill. It is used on gentle slopes. For large angles of inclination of slopes, the longitudinal method is used . In this case, the bulldozer blade, installed at an angle, first breaks through passage 1, then 2, 3, 4 and 5. Working with longitudinal passes is more productive, but special care must be taken, since the machine may slide laterally or tip over on a slope. . Therefore, for the safety of work, the transverse stability of the bulldozer is taken into account.

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Rice. 140. Soil loosening schemes:

A- longitudinal-circular, b - spiral, c - shuttle with displacement, d - longitudinal-transverse.

The choice of loosening scheme depends on the strength and nature of the rocks being mined.

When loosening category IV soils and hard rocks, it is advisable to organize the operation of machines according to longitudinal-ring and spiral patterns, since they provide the greatest productivity of the machine. Shuttle and longitudinal-transverse schemes are used when loosening rocks and permafrost soils. The latter scheme is used when it is necessary to obtain loosened rock of smaller sizes. It is additionally crushed by tractor tracks.

Areas of frozen soil are developed layer by layer to the maximum possible depth.

With a freezing depth of rocks of 50...70 cm, you can loosen the massif with three teeth. If the depth of rock development is greater, then use one tooth in two or three passes with a loosening depth of 30...40 cm for each cycle. When working on frozen rocks, the traction force of the machine is reduced by 35...45% due to a decrease in the coefficient of adhesion of the chassis to the ground.

Soils are loosened in the working gear of the tractor at a speed of 0.9...2.7 km/h. At the end of the working cycle, deepen the ripper and check for the presence of a removable tip. If you lose the tip, you can damage the toe of the stand and it will not hold the tip. In this case, the rack is replaced.

Rice. 141. Methods for developing soils and extracting minerals:

A-trench with feeding into vehicles by a loader, b - downhill with loading from a stack into vehicles with an excavator, c - two bulldozers-rippers with backfilling and from the dump into vehicles with a loader;

1 — bull-dozer-ripper; 2— loader, 3— vehicles, 4— excavator.

Loosened soils and rocks are removed by earthmoving and transport machines. The most effective way to develop hard, frozen rocks and minerals is with a bulldozer-ripper.

There are several rational schemes for organizing the work of a bulldozer-ripper in combination with loaders and excavators.

When developing a rock mass using the trench method, bulldozer-ripper 1 loosens the rock layer-by-layer at the bottom of the trench. Then, using bulldozer equipment with the ripper raised, the rock is moved into the stack by shuttle movements of the machine. From the stack, a single-bucket loader 2 loads the crushed material into vehicles 3 and transports it to the place of storage or processing.

A more rational scheme for loosening and removing rocks with a bulldozer downhill. A stack of material is formed at the bottom of the slope. From the stack, an excavator or loader loads the rock into vehicles. The productivity of the unit in this case is higher.

To coordinate the performance of loading equipment, sometimes two bulldozers-rippers are used, which first loosen the bottom of the trench with longitudinal-transverse moves, and then one bulldozer delivers the material to the storage site, and the other pushes it into the stack, from which the loader picks it up. rock and fills vehicles.

In open-pit mining, a complex squad of machines is used, which includes 3...5 bulldozers, rippers, an excavator or loader and several dump trucks. To avoid downtime, one bulldozer-ripper 3 only loosens the site. Several bulldozers 2 in parallel shift the loosened waste rock 4 into a stack, from which the excavator 1 loads it into vehicles 4 and transports it to the dump. After removing waste rock, minerals are developed in a similar way.

Rice. 142. Open-pit mining of minerals with preliminary loosening:

1 - excavator or loader, 2 - bulldozers, 3 - bulldozer-ripper, 4 - waste rock, 5 - vehicles, 6 - minerals.

The choice of excavation method depends on the properties of the soil, the volume of work, the type of earthworks, hydrogeological conditions and other factors. Process Excavation work consists of excavation, transportation, placement in a dump or embankment, compaction and leveling. To mechanize excavation work, single-bucket construction excavators with flexible and rigid suspension of working equipment in the form of a front and back shovel, dragline, grab, earth-moving, leveling and loading devices are used; continuous excavators, which include chain multi-bucket, chain scraper, rotary multi-bucket and rotary bucketless (milling); bulldozers, scrapers, graders (trailed and self-propelled), elevator graders, rippers, drilling machines. In addition to the leading earth-moving machine, the set of machines for mechanized soil development also includes auxiliary machines for transporting soil, cleaning up the excavation of the bottom, compacting the soil, finishing slopes, preliminary loosening the soil, etc., depending on the type of work.

Soil development using single-bucket excavators

In industrial and civil construction, excavators with a bucket with a capacity of 0.15 to 4 m3 are used. When performing large volumes of excavation work in hydraulic engineering construction, more powerful excavators with a bucket capacity of up to 16 m3 or more are used.

Wheeled excavators are recommended for use when working on soils with high load-bearing capacity with dispersed volumes of work, when working in urban environments with frequent relocations; crawler excavators are used for concentrated volumes of work with rare relocations, when working on soft soils and mining rocks; mounted excavators on pneumatic wheeled tractors - for dispersed volumes of work and when working in off-road conditions.

Soil development using single-bucket excavators is carried out by tunneling. The number of penetrations, faces and their parameters are provided for in the projects and technological maps carrying out excavation work for each specific object in accordance with the parameters of earthworks (according to working drawings) with the optimal working dimensions of excavator equipment.

Single-bucket excavators are classified as cyclic machines. The working cycle time is determined by the sum of individual operations: the duration of filling the bucket, turning to unload, unloading and turning to the face. The minimum time required to complete the work cycle is ensured under the following conditions:

the width of the penetrations (faces) is taken in such a way as to ensure the operation of the excavator with an average rotation of no more than 70 degrees;
the depth (height) of the faces must be no less than the length of the soil shavings required to fill the bucket with a cap in one digging step;
the length of the penetrations is taken taking into account the smallest possible number of entries and exits of the excavator into and out of the face.

The working area of an excavator is called the face. This zone includes the site where the excavator is located, part of the surface of the massif being developed and the installation site vehicles or a site for laying developed soil. The geometric dimensions and shape of the face depend on the equipment of the excavator and its parameters, the dimensions of the excavation, types of transport and accepted scheme soil development. IN technical specifications excavators of any brand, as a rule, their maximum indicators are given: cutting radii, unloading radii, unloading height, etc. When carrying out excavation work, optimal operating parameters are taken, amounting to 0.9 of the maximum passport data. The optimal height (depth) of the face should be sufficient to fill the excavator bucket in one scoop; it should be equal to the vertical distance from the excavator parking horizon to the level of the pressure shaft, multiplied by a factor of 1.2. If the face height is relatively small (for example, when developing a leveling excavation), it is advisable to use an excavator together with a bulldozer: the bulldozer develops the soil and moves it to the excavator’s workplace, then hills up the soil, while ensuring a sufficient face height. The excavator and vehicles must be positioned so that the average angle of rotation of the excavator from the point where the bucket is filled to the point where it is unloaded is minimal, since up to 70% of the working cycle time of the excavator is spent on turning the boom.

As the soil in the face is excavated, the excavator moves; the mined areas are called penetrations. Based on the direction of movement of the excavator relative to the longitudinal axis of the excavation, longitudinal (with a frontal or end face) and transverse (side) mining methods are distinguished. The longitudinal method consists of developing an excavation using penetrations, the direction of which is chosen along the largest side of the excavation. The frontal face is used when developing a ramp into a pit and when digging the beginning of an excavation on steep slopes. In frontal mining, the soil is mined over the entire width of the excavation. The end face is used when developing excavations below the excavator parking level, while the excavator, moving in reverse along the surface of the ground or at a level located above the bottom of the excavation, develops the end of the excavation. Side faces are used to develop an excavation with a straight shovel, while the vehicle paths are arranged parallel to the axis of movement of the excavator or above the bottom of the face. With the lateral method, the full width of the penetration can be obtained by sequentially developing a series of penetrations. The transverse (lateral) method is used to develop excavations with soil filling in the direction perpendicular to the axis of the excavation. The transverse method is used when developing long, narrow excavations with filling of cavaliers or when constructing embankments from lateral reserves.

Some types of excavations (for example, leveling) can be developed using a side face with traffic flowing at the same level as the excavator. Sometimes, in order to proceed to development with a side face, it is first necessary to tear off the so-called pioneer trench, which the excavator begins to develop by descending to the bottom of the face along a ramp. If the height of the excavator unloading is greater than or equal to the sum of the depth of the excavation, the height of the side of the dump truck and the “cap” above the side (0.5 m), the pioneer trench is developed using a side face while vehicles are moving along the daytime surface at a distance of at least 1 m from the edge of the excavation. If the excavation is large in terms of size, it is developed by transverse penetrations along the smaller side, while ensuring the minimum length of the pioneer trench, which allows organizing the most productive circular traffic movement. Excavations, the depth of which exceeds the maximum depth of the face for a given type of excavator, are developed in several tiers. In this case, the lower tier is developed similarly to the upper one, and the cars are delivered to the excavator so that the bucket is located on the back of the body. In this case, the vehicle's route should be parallel to the axis of the excavator's excavation, but directed in the opposite direction.

An excavator equipped with a backhoe is used when excavating soil below the parking lot level and is most often used when digging trenches for laying underground utilities and small pits for foundations and other structures. When working with a backhoe, a front or side face is also used. It is most advisable to use an excavator with a backhoe to develop pits with a depth of no more than 5.5 m and trenches up to 7 m. The rigid fastening of the backhoe bucket gives it the ability to dig narrow trenches with vertical walls. The depth of the narrow trenches being mined is greater than the depth of the pits, since the excavator can lower the boom with the handle to the lowest position, maintaining stability.

An excavator with dragline working equipment is used when developing large and deep pits, when constructing embankments from reserves, etc. The advantages of the dragline are a large radius of action and a digging depth of up to 16-20 m, the ability to develop faces with a large influx of groundwater. Dragline develops excavations using end or side penetrations. For end and side penetrations, the organization of dragline work is similar to the work of a backhoe. At the same time, the same ratio of maximum cutting depth is maintained. The dragline usually moves between stops by 1/5 of the boom length. Soil development with a dragline is most often carried out into a dump (one-sided or two-sided), less often - for transport.

Excavators dig out pits and trenches to a depth somewhat less than the design one, leaving a so-called shortfall. The shortfall is left in order to avoid damage to the base and to prevent oversupply of the soil; it is usually 5-10 cm. To increase the efficiency of the excavator, a scraper knife mounted on a bucket is used. This device allows you to mechanize operations for cleaning the bottom of pits and trenches and carry them out with an error of no more than plus or minus 2 cm, which eliminates the need for manual modifications.

Soil development by continuous excavators is carried out in the absence of stones, roots, etc. in the soil. Before starting work along the trench route, a bulldozer plans a strip of land at least as wide as the width of the crawler track, then the axis of the trench is broken and secured, after which it begins to be pulled out from the low side marks (for water drainage). Bucket excavators excavate trenches of limited dimensions and, as a rule, with vertical walls.

Soil development using earthmoving and transport machines

The main types of earth-moving and transport machines are bulldozers, scrapers and graders, which in one cycle develop soil, move it, unload it into an embankment and return empty to the face.

Excavation work using bulldozers

Bulldozers are used in construction to develop soil in shallow and extended excavations and reserves to move it into embankments at a distance of up to 100 m (when using more powerful machines, the distance of soil movement can be increased), as well as for clearing territory and planning work, for cleaning foundations under embankments and foundations of buildings and structures, when constructing access roads, excavating soil on slopes, etc.

Rice. 7. :
a - normal cutting; b - comb cutting

In the practice of earthworks, there are several ways to cut soil with a bulldozer (Fig. 7):

ordinary cutting - the knife is first buried to the maximum depth for a given soil and, as it is loaded, gradually rises, as the resistance of the drawing prism, which consumes the traction force of the tractor, increases;
comb cutting - the dump is filled with several alternating depressions and elevations.

The comb pattern allows you to reduce the cutting length by increasing the average chip depth. In addition, with each deepening of the knife, the soil under the drawing prism is chipped off and the already cut soil is compacted on the dump. This reduces cutting time and increases the volume of soil on the dump.

When carrying out excavation work with bulldozers, the method of cutting downhill, based on the rational use of tractor traction, is successfully used. Its essence is that when the tractor moves downhill, part of the traction force necessary to move the machine itself is released, due to which the soil can be destroyed in a thicker layer. When the bulldozer operates downhill, soil chipping is facilitated and the resistance of the drawing prism, which moves partially under the influence of its own weight, is reduced. If there is no natural slope, it can be created by the first penetrations of a bulldozer. When working at a slope of 10-15 degrees, productivity increases by approximately 1.5-1.7 times.

Rice. 8. :
a - single-layer cutting; b - trench cutting. The numbers indicate the cutting order

The bulldozer operates according to the diagrams shown in Fig. 8. By single-layer cutting with overlapping strips by 0.3-0.5 m, the plant layer is removed. Then the bulldozer moves the soil into the dump or intermediate shaft and returns to the new cutting site without turning, in reverse (shuttle pattern), or with two turns. Trench development is carried out by leaving lintels 0.4 m wide in cohesive soils and 0.6 m wide in loosely cohesive soils. The trench depth is assumed to be 0.4-0.6 m. Lintels are developed after each trench has been passed.

Excavation work using scrapers

The operational capabilities of scrapers allow them to be used when excavating pits and leveling surfaces, and when constructing various excavations and embankments. Scrapers are classified:

according to the geometric volume of the bucket - small (up to 3 m3), medium (from 3 to 10 m3) and large (over 10 m3);
by type of aggregation with a tractor - trailed and self-propelled (including semi-trailer and saddle-mounted);
according to the method of loading the bucket - loaded due to the traction force of the tractor and with mechanical (elevator) loading;
according to the method of unloading the bucket - with free, semi-forced and forced unloading;
according to the method of driving the working bodies - hydraulic and rope.

Scrapers are used to develop, transport (soil transportation range ranges from 50 m to 3 km) and lay sandy, sandy loam, loess, loamy, clay and other soils that do not have boulders, and the admixture of pebbles and crushed stone should not exceed 10%. Depending on the category of soil, cutting them is most effective on a straight section of the path when moving at a slope of 3-7 degrees. The thickness of the developed layer, depending on the power of the scraper, ranges from 0.15 to 0.3 m. The scraper is unloaded in a straight section, while the soil surface is leveled with the bottom of the scraper.

Rice. 9. :
a - with filling the ladle with chips of constant thickness; b - with the bucket filled with chips of variable cross-section; c - comb method of filling the ladle with chips; d - filling the bucket using the peck method

There are several ways to cut chips when operating a scraper (Fig. 9):

chips of constant thickness. The method is used for planning work;
chips of variable cross-section. In this case, the soil is cut off with a gradual decrease in the thickness of the chips as the bucket is filled, i.e., with a gradual deepening of the scraper knife towards the end of the set;
comb method. In this case, the soil is cut with alternating depth and gradual lifting of the scraper bucket: at different stages, the thickness of the chips varies from 0.2-0.3 m to 0.08-0.12 m;
pecks. Filling the bucket is carried out by repeatedly deepening the scraper knives to the greatest possible depth. The method is used when working in loose granular soils.

Depending on the size of the earthen structure, the relative position of the excavations and embankments, different operating schemes for scrapers are used. The most common is the ellipse work pattern. In this case, the scraper turns in one direction each time.

Rice. 10. :
a - trench-comb; b - ribbed checkerboard

When working in wide and long faces, the scraper bucket is filled using trench-comb and ribbed-checkerboard methods. With the trench-ridge method (Fig. 10), the face is mined from the edge of the reserve or excavation in parallel strips of constant depth 0.1-0.2 m, equal in length. Between the stripes of the first row, strips of uncut soil are left - ridges, equal in width to half the width of the bucket. In the second row of passes, soil is taken to the full width of the bucket, cutting off the ridge and forming a trench under it. The thickness of the chips in this case in the middle of the bucket is 0.2-0.4 m, and at the edges 0.1-0.2 m.

With the ribbed-checkerboard method (Fig. 10), the face is developed from the edge of the excavation or reserve in parallel strips so that between the scraper penetrations there remain strips of uncut soil equal in width to half the width of the bucket.

The second row of penetrations is developed, retreating from the beginning of the first row by half the length of the penetration of the first row. The work of a scraper should be combined with the work of a bulldozer, using them to develop elevated areas and move soil short distances to low places.

Excavation work using graders

Graders are used when leveling the territory, slopes of earthen structures, cleaning the bottom of pits and digging ditches up to 0.7 m deep, when constructing extended embankments up to 1 m high and the lower layer of higher embankments from the reserve. Motor graders are used to profile road surfaces, driveways and roads. It is most effective to use motor graders with a penetration length of 400-500 m. Dense soils are pre-loosened before development with a grader. When constructing an embankment from a developed reserve, an inclined knife moves the cut soil towards the embankment. The next time the grader passes, this soil moves even further in the same direction, so it is advisable to organize the work with two graders, one of which cuts and the other moves the cut soil.

When constructing embankments and profiled road surfaces, soil cutting begins from the inner edge of the reserve and is carried out layer by layer: first, triangular shavings are cut, then until the end of the layer the shavings are rectangular. When developing wide reserves in soils that do not require preliminary loosening, cutting begins from the outer edge of the reserve and is carried out layer by layer, with all passes of triangular-shaped chips; Another method is possible: the chips are obtained in triangular and quadrangular shapes.

When executing various operations The grader's tilt angles vary within the following limits: grip angle - 30-70 degrees, cutting angle - 35-60 degrees, tilt angle - 2-18 degrees. In construction practice, several methods of laying soil are used:

the soil is laid in layers, pouring it from the edge to the axis of the road (grading work at zero marks with an embankment height not exceeding 0.1-0.15 m);
the rollers are placed one next to the other with only their bases touching (filling embankments with a height of 0.15-0.25 m);
each subsequent roller is partially pressed against the previously laid one, overlapping it with the base by 20-25%; the ridges of these two rollers are located at a distance of 0.3-0.4 m from one another (filling embankments up to 0.3-0.4 m high);
each subsequent roller is pressed against the previously laid one without any gap; the new roller is moved with a blade close to the previously laid one, gripping it by 5-10 cm; one wide, dense shaft is formed 10-15 cm higher than the first roller (filling embankments up to 0.5-0.6 m high).

Development of frozen soils

Frozen soils have the following basic properties: increased mechanical strength, plastic deformation, heaving and increased electrical resistance. The manifestation of these properties depends on the type of soil, its humidity and temperature. Sandy, coarse-grained and gravel soils, lying in a thick layer, as a rule, contain little water and at low temperatures almost do not freeze, so their winter development is almost no different from summer. When excavations and trenches are developed in dry, loose soils in winter, they do not form vertical slopes, do not heave, and do not cause subsidence in the spring. Silty, clayey and wet soils change their properties significantly when they freeze. The depth and speed of freezing depends on the degree of soil moisture. Excavation work is carried out in winter using the following methods:

by the method of preliminary soil preparation followed by their development using conventional methods;
method of preliminary cutting of frozen soil into blocks;
method of soil development without preliminary preparation.

Preliminary preparation of soil for development in winter consists of protecting it from freezing, thawing frozen soil and preliminary loosening of frozen soil. The simplest way to protect the soil surface from freezing is to insulate it with thermal insulation materials; For this purpose, peat fines, shavings and sawdust, slag, straw mats, etc. are used, which are laid in a layer of 20-40 cm directly on the ground. Surface insulation is used mainly for small-area recesses.

To insulate large areas, mechanical loosening is used, in which the soil is plowed with tractor plows or rippers to a depth of 20-35 cm, followed by harrowing to a depth of 15-20 cm.

Mechanical loosening of frozen soil at a freezing depth of up to 0.25 m is carried out with heavy rippers. When freezing to 0.6-0.7 m, when digging out small pits and trenches, the so-called loosening by splitting is used. Impact frost plowers work well when low temperatures soil when it is characterized by brittle deformations that contribute to its splitting under the influence of an impact. To loosen the soil at a large freezing depth (up to 1.3 m), a diesel hammer with a wedge is used. Development of frozen soil by cutting involves cutting mutually perpendicular furrows with a depth of 0.8 of the freezing depth. The block size should be 10-15% smaller than the size of the excavator bucket.

Thawing of frozen soil is carried out using hot water, steam, electric current or fire. Thawing is the most complex, time-consuming and expensive method, so it is resorted to in exceptional cases, for example, during emergency work.

V. Preparation of foundations for embankments

1. Cutting plant soil and cutting ledges on slopes

On horizontal terrain, as well as on slopes with a steepness of up to 1:10, embankments more than 0.5 m high on a dry and solid base are poured directly onto the natural surface, and at the base of embankments up to 0.5 m high, the vegetation cover (turf) is removed.

When the slope slope is from 1:10 to 1:5, at the base of embankments up to 1.0 m high and in zero places, the turf is also removed, and at the base of embankments with a height of more than 1 m, the turf is not cut off, but before filling the embankment from clay soils, the base surface is loosened .

Within slopes with a steepness of 1:5 to 1:3, regardless of the height of the embankment, ledges are arranged with a width of 2 to 4 m, but not less than 1 m, and a height of up to 2 m with a transverse slope to the downstream side of 0.01-0.02.

Removal of vegetation cover and cutting of ledges is carried out using bulldozers or motor graders.

On a slope, it is advisable to cut off the plant soil during the working movement of a bulldozer or motor grader from top to bottom. In this case, the soil is placed from the downstream side of the embankment into a berm or removed.

Cutting ledges can be done before the construction of embankments from top to bottom (Fig. 29, a), starting from the upland boundary of the embankment slope, or during the construction of the embankment from bottom to top (Fig. 29, b), starting from the submountain boundary of the embankment slope. In the first case, the width of the ledges must be at least 3 m (based on the installation of a bulldozer), and in the second case it can be reduced to 1 m. The lower ledge in both cases must be made at least 4 m wide in order to accommodate what is unloaded from dump trucks soil and a soil compaction machine during the construction of an embankment.

The ledges are cut using a bulldozer or motor grader. The most effective is a universal bulldozer with a blade installed at an angle to its longitudinal axis.

When cutting ledges from top to bottom, before erecting an embankment, the soil is moved by a bulldozer in the longitudinal or transverse direction. In the latter case, it is placed in a berm.

The ledges are cut from bottom to top as the embankment is erected. First, the lower ledge is cut, in place of which layers of embankment are then poured. After filling the layer of soil to the level of the top of the ledge, the next ledge is cut, etc. The soil of the ledge is leveled across the width of the poured layer, if it is suitable for laying in the embankment, or is removed beyond the embankment.

To impart a transverse slope to the ledges, it is advisable to use a motor grader.

2. Construction of trenches and drainage slits in swamps

Soils of weak foundations with embankment heights of up to 2 m are pre-drained or cut out. In swamps, partial or complete removal of peat from the base of embankments is provided and the resulting trenches are backfilled with soils suitable for the construction of embankments.

Trenches up to 4 m deep are usually developed using dragline excavators of the E-652 type with a TsNIIS bucket with a capacity of 0.8 m3.

In swamps with insufficient bearing capacity, it is advisable to carry out foundation preparation work in winter time. In summer, excavators move on portable shields. It is advisable to use excavators and bulldozers with wide tracks.

The peat removed from the trench by an excavator is then moved by a bulldozer and leveled in a layer 0.5 m thick. If it is impossible to use a bulldozer due to the insufficient bearing capacity of the swamp surface, the peat is thrown over with an excavator or left unleveled in the winter, leveled with a bulldozer in the spring as it thaws.

The development of a trench with an excavator, depending on its width, is carried out using end (Fig. 30, a) or side (Fig. 30, b) face in one or several penetrations.

The productivity of the excavator in the end face is higher than in the side face.

The trench development scheme with an end face is used in cases that do not require the preliminary installation of drainage ditches.

According to the development scheme with a side face, simultaneously with the development of the trench, it is possible to construct a drainage ditch on the side of the excavator.

In both schemes, an E-652 type dragline excavator with a 13 m long boom makes trenches up to 12 m wide and 2.5 m deep.

Development of trenches up to 25m wide (Fig. 30, V) is carried out by a side face with two penetrations. The excavator moves to the side of the trench, develops it half its width, and then develops the other half on the way back. With each excavator pass, it is possible to create a drainage ditch.

Trenches more than 25m wide (Fig. 30, G) are arranged with three excavator passes. Simultaneously with the development of parts of the trench, drainage ditches can be installed.

Trenches up to 1 m deep in dry swamps with underlying dense soils with a base width of more than 12 m can be effectively developed with bulldozers. In this case, it is advisable to use bulldozers with wide caterpillar tracks, as well as with scoop-type blades.

Excavation of soil with bulldozers is carried out by transverse penetrations. The peat is moved beyond the location of the drainage ditches and leveled in a layer up to 0.5 m thick. Drainage ditches are installed after peat removal.

In swamps, to ensure vertical drainage of the base of embankments, as well as to accelerate the consolidation (hardening) of base soils and increase their stability, longitudinal drainage cuts are sometimes installed.

To construct drainage slots, dragline excavators, backhoes, and trench bucket excavators are used.

Draglines are used in the summer when the swamp depth is up to 4 m. Trench multi-bucket excavators are used in swamps with a depth of no more than 3 m both in summer and winter, and in the summer - on widened caterpillar tracks, and in winter - with special replaceable working equipment designed for the development of frozen soils.

Backhoe excavators of the E-652 type can be used to construct drainage slits in winter in swamps up to 4 m deep and with a freezing thickness of no more than 0.3 m.

The peat removed from the slot is moved with a bulldozer and leveled in a layer up to 0.5 m thick.

Following the excavation, the slots are filled with drainage soil (simultaneously with the construction of the embankment).

3. Preparation of foundations for embankments on mari, areas with underground ice, kurums and stone placers.

Preparation of foundations for embankments on mari is to ensure the drainage of surface water, eliminating the possibility of its accumulation at the base of the slope, filling low areas, as well as lakes of thermokarst origin located near the embankment.

Backfilling is carried out with local clay soil as the bottom layer of the embankment is filled. Clay soil, delivered by dump trucks along the filled layer of the embankment, is unloaded near the lower surface and then pushed forward with a bulldozer.

The top of the embankment is designed in the form of a berm with a height above the mari surface of 0.2-0.3 m with a transverse slope of 0.02-0.04 away from the embankment.

As a rule, peat removal is not provided within the mires.

In the permafrost zone, in areas of embankments up to 1 m high, as well as in zero places, at the base of which there are waterlogged clay soils, it is necessary to cut out these soils to a depth of at least half the thickness of the active layer, giving the bottom of the trench a longitudinal slope of at least 0.005.

The cutting of soil in a thawed state is carried out using bulldozers. Frozen soils are pre-loosened with mounted rippers on bulldozers with a power of 300 hp. With. and more or explosively. The loosened soil is moved by bulldozers into shafts, from which it is loaded with an excavator into dump trucks and taken away beyond the embankment.

It is advisable to carry out work on loosening permafrost soils at high positive air temperatures with a certain interval (in time) between loosening individual layers of soil. During the time between removing the loosened layer of soil and loosening the next layer, the strength of the frozen soil decreases and its loosening requires less effort.

If there are subsidence foundations in areas of underground ice, both during the preparatory period and during the construction of embankments, measures should be taken to maximally preserve the natural conditions of the right-of-way in order to prevent thawing of ice and associated subsidence of embankments. To do this you need:

do not disturb the vegetation and moss cover at the base of the embankments and in the right of way;

felling of trees should be carried out in the minimum required quantity;

do not allow drainage of the wetland and the construction of longitudinal and transverse slits at the base and at the bottom of the embankment slope;

erect embankments after freezing of the active layer and, before the onset of positive temperatures, pour it to a height of at least 1.2 m;

systematically remove snow from the entire area of the base, which helps to increase the depth of freezing of the base soil;

allocate areas with underground ice to a restricted zone and, during the construction and operation process, prevent off-road traffic, construction of various structures, haymaking, etc. in this zone.

In areas where underground ice occurs directly under the active layer, in some cases it is planned to completely or partially remove this ice from the base of the embankments to a certain width. When the ice is completely removed, I fill the trench with drainage soil, and when the ice is partially removed, I fill it with clay soil. In the latter case, the thickness of the bulk soil together with the embankment above the remaining ice must be at least 4 m. The slope of the trench is given a slope of 1: 0.2.

The process for removing active layer soil is indicated above. The ice is loosened by explosive means, and individual layers and lenses of ice are loosened by mounted rippers on bulldozers with a power of 300 hp. With. and more. The loosened ice is moved into shafts by a bulldozer and loaded into dump trucks by an excavator. In winter, loosening the soil of the active layer and ice by blasting should be carried out simultaneously.

The trench is filled with soil delivered by dump trucks. In summer, the first layer of soil must be poured without dump trucks driving onto the surface of the ice or permafrost soil of the trench. To do this, the soil unloaded by dump trucks is pushed forward with a bulldozer. Dump trucks are turned around for unloading on previously planned ground near the unloading site. The dumped soil is compacted layer by layer using soil compaction machines until established norm density.

Part 1

Bulldozers perform operations as follows. Layer-by-layer development and movement of materials produced at a transportation distance of 50...150 m. Long distances of movement are economically beneficial for heavy bulldozers. During surface mining of soils and minerals, the machine is characterized by shuttle movements, alternating the working stroke and moving back empty. It is advisable to collect and transport soil in one pass with the formation of side rollers, the trench method, the paired operation of bulldozers, and the formation of several prisms. In light ground conditions, additional replaceable bulldozer equipment (openers, extensions, extensions) is used.

Construction of embankments carried out in two ways: by transverse passages from the reserve (Fig. 137, I) and longitudinal one-way movements of the machine (Fig. 137, II).

Rice. 137. Basic excavation bulldozer work

When transversely moving soil from reserves, it is advisable to use the trench method of developing materials and the paired operation of several machines. The first prisms are fed to the center of the embankment, the subsequent ones - closer to its edges.

The drawing prisms are placed pressed together. The rise of the embankment slopes along which soil is supplied should not exceed 30%. With large elevations of the embankment, the work is ineffective.

Development of excavations produced by longitudinal double-sided passes (Fig. 137, III) and transverse passages (Fig. 137, IV). The longitudinal two-way method provides greater productivity of bulldozers. It is used for short excavations and in cases where the soil removed from the excavation is completely placed in adjacent embankments. The transverse excavation method is used when excess soil is placed in cavaliers along the future road surface.

Excavation of canals, irrigation structures, trenches, pits produced by transverse moves of the bulldozer with a gradual displacement of the machine along the structures (Fig. 137, V). The soil is placed in cavaliers along the entire length of the canals, creating earth banks on both sides. The soil is excavated in parallel trenches with a depth no greater than the overall height of the machine. The distance between the trenches is up to 0.4...0.6 m. After the passage, the intertrench jumper is destroyed. In this case, group operation of machines with paired parallel moves is effective.

Planning work carried out on a flat surface, cutting off small mounds and filling in depressions, holes, and ravines. Large depressions are filled up from neighboring slopes with longitudinal passages (Fig. 137, VI). The last passes are made offset by 3/4 of the blade width to prevent the appearance of side rollers. After a rough front layout (see Fig. 130, G) it is advisable to finish the surface while moving the bulldozer in reverse (see Fig. 130, V) and the “floating” position of the blade. For greater accuracy, it is advisable to use mutually perpendicular passages of bulldozers.

Rice. 130. Main types of work performed by bulldozers: A- development of trenches, pits, channels with soil filling into cavaliers, embankments, b- cutting of slopes and filling of excavations, V- removal of fertile layer or waste rock, G- forward layout, d- forward leveling, e- rearward planning, and- backfilling of trenches, h- pushing scrapers when filling the bucket with soil, And- loading soil into vehicles from the overpass, To- loading materials into transport from a tray, l- felling trees, m- uprooting stumps, n- cutting of bushes and small forests, O- snow removal works; 1 - initial position of the bulldozer, 2 - cutting and transporting soil, 3 - bulldozer on an embankment, 4 - embankment or cavalier, 5 - trench, 6 - slope, 7 - excavation, 8 - fertile layer or waste rock, 9 - minerals and building materials, 10 - scraper, 11 - overpass, 12 - vehicles, 13 - loading chute

Punching terraces and shelves on slopes carried out by bulldozers with fixed and rotary blades. The most effective and safe way to move soil from a slope to a half-embankment is by transverse passes of the machine downhill (Fig. 138, I). It is used on gentle slopes. For large angles of inclination of slopes, the longitudinal method is used (Fig. 138, II). In this case, the bulldozer blade, installed at an angle, first breaks through passage 1, then 2, 3, 4 and 5. Working with longitudinal passes is more productive, but special care must be taken, since the machine may slide laterally or tip over on a slope. Therefore, for the safety of work, the lateral stability of the bulldozer is taken into account.

Rice. 138. Development of slopes with a bulldozer

Backfilling of trenches produced by bulldozers with a non-rotating (Fig. 139, A) or a rotary blade (Fig. 139, b). This operation is performed with straight passes perpendicular to the axis of the trench, or with oblique movements at a certain angle to it.

Rice. 139. Filling trenches with bulldozers: A- with a fixed blade, b- with a rotary blade; 1 - soil embankment, 2 - trench

A bulldozer with a fixed blade grabs some of the soil from the embankment and moves it into the trench. If the depth of the trench is 1.5 m or more, then the soil is poured through one or two prisms to prevent the walls of the trench from collapsing and the bulldozer from sliding into it. After the first pass, the bulldozer moves in reverse and the operation is repeated.

For a bulldozer with a rotating (wider) blade, it is installed at an angle to the right to the longitudinal axis of the machine and with oblique strokes at an angle of 30...40° they push the soil into the trench. The use of bulldozers with a rotary blade is more effective for this work, since the soil is partially shifted to the side when colliding.

Pushing scrapers(see Fig. 130, h) are carried out by bulldozers when collecting soil and exiting a loaded scraper from a face with a large slope of access roads.

Loading soil into vehicles from an overpass(see Fig. 130, And) are produced primarily in sand quarries. The overpass is built in a trench dug by a bulldozer. Using longitudinal moves, the bulldozer moves the material to the overpass bunker and loads the dump trucks. The bulldozer works through one or two prisms so as not to cause the overpass to collapse. Loading soil into vehicles from a tray is shown in Fig. 130, To.

Felling trees(see Fig. 130, l) is carried out by focusing the maximum raised blade into the barrel.

Uprooting stumps(see Fig. 130, m) can be done with a straight blade or a skewed blade. First, with the deepest depth of the blade, the roots of the stump are cut off with middle or corner knives and rocked by repeatedly engaging the clutch. Then, with the simultaneous forward movement of the machine and lifting of the working equipment, the stump is uprooted. Large stones and boulders that are partially on the surface are removed from the ground in a similar manner.

Cutting shrubs and small forests(see Fig. 130, n) is produced with a straight blade lowered into the ground to a depth of 10...20 cm, with the entire bulldozer moving forward. As heaps of bushes, roots, and small trees accumulate, they are moved with a turning movement away from the cleared route.

Snow removal(see Fig. 130, O) are performed to maintain roads in good condition. The most effective in this case is a bulldozer with a rotating blade with an oblique working body.

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