Technique for removing the top layer of soil. Removal of vegetative soil and preparation of the subgrade base
Fertile soil layer removed from the entire area allotted for the construction of the road, and placed in dumps for further use. The thickness of the removed fertile soil layer is established by the project on the basis of preliminary agreement with land users. The thickness of the vegetation layer in turfed areas is noticeably 8 ... 12 cm, arable - 15 ... 18 cm and forested - 15 ... 25 cm. Vegetable soil is used to strengthen the slopes of the subgrade, reclamation of restored or low-productive agricultural lands.
There are the following schemes for removing the vegetative layer of soil: a) transverse with soil rolls arranged in a checkerboard pattern with a strip width of less than 20 ... 25 m; b) transverse with rollers on both sides of the roadbed with a strip width of more than 20 ... 25 m; c) longitudinal-transverse with a cut-off strip width of more than 35 m and a significant thickness of the vegetation layer of the soil (Fig. 3.4.1).
Rice. 3.4.1. Scheme for cutting and moving plant soil:
a - transversely on a strip 20 ... 25 m wide; b - the same, on a strip with a width of more than 20 ... 25 m; in - longitudinal-transverse way; I - shaft of vegetative soil; 1, 2, 3 ... n - bulldozer passes
For cutting and moving the vegetation layer of the soil, bulldozers or motor graders are used. The method of performing this work is chosen depending on the width of the strip from which it is necessary to cut the soil and the thickness of the cut layer. If the width of the strip is less than 20 ... 25 m, which happens when erecting a subgrade from imported soil, the vegetative soil is cut off and moved by a bulldozer over the entire width at once (Figure 3.4.1, a). Each cycle of cutting and moving the soil is carried out with an overlap of the previous layer by 20 ... 25 cm.With a wider strip, for example, if it is necessary to cut off plant soil from the surface of the embankment base and lateral reserves, the soil is moved alternately in both directions from the axis of the road, starting each time cutting from the axis (Fig. 3.4.1, b).
With a large volume of work, a longitudinal-transverse scheme of cutting and moving the soil is used: the soil is cut off with the longitudinal passes of the bulldozer and collected into shafts, then it is moved outside the cutting strip with transverse passes. It is rational to carry out this work, using simultaneously a motor grader and a bulldozer: the first for cutting the soil and laying it in the longitudinal shafts, the second for the transverse movement of the plant soil outside the strip of removal of the vegetation layer. You can also cut the soil with a scraper, moving it over a distance of more than 50 m. The scraper removes the vegetation layer with longitudinal passes, parallel to the axis of the road, on a cut-off strip, equal to the length of the grab, but not less than 200 ... 250 m. The way of filling the bucket with a capacity of 6 .. .8 m 3 is 20 ... 25 m with a chip thickness of about 10 cm, after which the scraper is transferred to the unloading position and the soil is unloaded into a transverse roller. Continuing to move, the scraper cuts the soil again until the bucket is full and unloads it again in the adjacent area. Similar operations are repeated until the end of the grip, where the scraper, having turned 180 °, continues to cut the vegetation layer in the opposite motion. Then the transverse rollers of soil are moved by the bulldozer outside the cutting strip.
Bulldozer performance P, m 3 / shift, when cutting and moving the vegetation layer of the soil is equal to
(3.4.1)
where T- duration of the shift, h;
Q- the volume of soil moved in one cycle, m 3;
To in- coefficient of use of time;
K i- coefficient taking into account the presence of a slope;
K n- coefficient that takes into account the loss of soil during its movement;
t- time spent on one cycle, h;
K p- coefficient of soil loosening.
Vegetable soil is placed in temporary dumps or taken directly to the place of use as a fertile soil layer. Temporary dumps are located at the edges of the right-of-way or at special areas designated for this purpose.
Land reclamation or restoration of the fertile soil layer is carried out where it was damaged or completely destroyed during the construction process. Such places include territories occupied by temporary roads, parking lots for road vehicles, unpaved, sandy or gravel pits, lateral reserves.
a) Dimensions of the pit (along the bottom):
Length: 60 m, Width: 50 m, Depth: 4.5 m.
b) Soil: loam
c) Thickness of the vegetation layer: 0.2 m.
d) Distance to dump: 1.5 km.
Determination of composition preparatory work
Calculation of the scope of work
Preparatory work must be completed before starting the excavation. These works are intended to clear the area for the pit.
They include:
removal of the vegetation layer (trees, shrubs) by cutting;
removal of stones;
leveling the surface.
Calculation of the size of the pit.
Pit volume
To determine the volume of the pit, we will use the formula:
V boiler = H / 6 (a * b + a 1 * b 1 + (a + a 1) (b + b 1),
where H is the depth of the pit, m;
a and b - dimensions of the pit at the bottom - dimensions of the bottom of the pit, m;
a 1 and b 1 - dimensions of the pit on top, m;
Figure 1. Determination of the volume of the pit
m = L / H, then L = mH,
L = 0.9 * 9.5m = 8.55m (for clay with a pit depth of 9.5 m. M = 0.9).
The dimensions of the pit on top:
where m is the slope setting coefficient, for pits excavated with a straight shovel in loam, this coefficient is taken equal to 0.9.
a 1 = 60 + 2 * 0.9 * 9.5 = 77.1 m;
b 1 = 50 + 2 * 0.9 * 9.5 = 58.55m;
The value of the slope setting coefficient "m" is taken from Table 1.
Coefficient of setting the slope of the pit in soft non-watered soils. Table 1.
Knowing all the data, we find the volume of the pit:
V boiler = 9.5 / 6 = 35444 m 3
Crop volume
V rast = a 1 * b 1 * h rast,
where h rast is the thickness of the vegetation layer, m;
h rast = 0.2 m;
Then: V rast = 77.1 * 58.5 * 0.2 = 902 m 3
The volume of soil to be developed
The volume of soil to be developed:
V gr = V boiler - V rast;
We get the volume of soil removed to the dump equal to:
V gr = 35444-902 = 34542m 3.
Removing the vegetation layer
When using excavators to excavate the excavation pit, the removal of the vegetation layer is usually carried out:
Bulldozers up to 10 tons of thrust (with the length of the work area up to 100 m);
Scrapers (with the length of the work site over 100 m).
The total length of the working area is:
,
(7)
where 
- the distance from the edge of the pit to the axis of the cavalier ( 
).
This means that we take a bulldozer to remove the vegetation layer (from table 4). Chosen bulldozer DZ-18, its characteristics:
Blade length - 3.97 m,
Blade height - 0.815 m,
Cutting angle - 47 0 -57 0,
Skew angle -5 0,
The angle of rotation in the plan - 63 0 and 90 0,
Lifting height - 1 m,
The way to change the skew angle is manually,
Blade control - hydraulic,
Power - 79 kW / h,
Traction - 10 t,
Removal of the vegetation layer can be carried out according to the following schemes:
In this project:
therefore, we use a two-sided scheme for removing the vegetation layer of the soil, shown in the drawing (see drawing 5, appendix P). The bulldozer develops the soil, moving shuttle from the longitudinal axis of the pit to the axis of the cavalier. The ground movement distance varies from 
when cutting and recruiting a soil prism at the longitudinal axis of the excavation up to 
when cutting soil at the edge of the site; therefore, on average it is 
The distance, including the temporary berm and half of the cavalier's width, can be taken equal to 5 + 5 = 10 m.
The operational performance of the bulldozer is determined by the formula:
P e h = q q * n q * K in,
where P e h is the operational performance of the bulldozer, m 3 / h,
K in - the coefficient of the use of working time, for a bulldozer we will take it: K in = 0.8.
n c - the number of cycles per hour of operation of the bulldozer
Estimated volume of soil in front of the dump at the end of the transportation section q q:
q q = q ’t * K e,
where q ’c - the volume of the soil prism after the completion of the digging operation (set of soil into the prism), m 3,
K z - load factor of the working body,
K s = K p * 1 / K p * K yk,
where K p is the coefficient of soil loss into the side rolls during transportation of the soil prism to the unloading point. It takes into account the loss of soil from the prism by dragging into the side rollers during transport.
The value depends on the travel distance, soil connectivity and moisture, the blade design and the way the soil is moved.
K n = 1 - 0.005 * l tr,
where l tr is the average transport length, m,
l tr = a 1/4 + s,
l tr = 77.1 / 4 + 10 = 29.28 m.
K n = 1 - 0.005 * 29.28 = 0.85,
K p - coefficient of soil loosening;
Let us take K p = 1.2
- working time utilization rate
We accept 
.
К uk - coefficient of the slope of the terrain;
We take K yk = 1
With the number of cycles per hour of operation of the bulldozer n c = 3600 / t c.
Then the formula for determining the estimated average hourly operational productivity has the form
P h e = q ’c * 3600 / t c * K p * 1 / K p * K uk * K v;
The volume of the soil prism depends on the size of the dump and the properties of the soil:
q ’c = B * H 2/2 * 1 / K pr,
where B is the length of the blade, m;
Н - blade height, m;
K pr is the coefficient of filling the geometric volume, determined according to table 22:
According to the initial data, the soil is cohesive.
q "q = 2.64 / 2 * 1 * 1 / 0.55 = 2.4m 3.
The duration of the working cycle of the bulldozer t c is determined by the formula:
t c = t to + t tr + t p + t p + t add,
where t to - the duration of digging, s,
t to = l to / v to;
Also t to can be determined from table 24.
t tr - the duration of the transport of the soil prism, s,
t tr = l tr / v tr,
where l tr = 29.28 m,
v tr - transportation speed, m / s, determined according to table 24;
According to the initial data, the traction force is 100 kN, soil type III.
v tr = 0.7 m / s;
t tr = 29.28 / 0.7 = 42 s.
t p - the duration of the layout of the soil, s. With concentrated unloading of the prism, it is taken equal to t p = 0 s,
t p - the duration of the empty run, s,
t p = (l k + l tr + l p) / 2 * v p,
where l to - the length of the digging path, m, is taken equal to l to = 5 m;
l tr = 29.28 m;
v p - empty speed, m / s, determined according to table 24;
According to the initial data, the traction force is 100 kN, soil type III.
v p = 1.23 m / s;
t p = (5 + 28.29 + 0) / 2 * 1.23 = 21s,
t add - additional time for shifting gears, setting the blade and turning the bulldozer, s,
Let's take t add = 20 s
t c = 14.4 + 42 + 0 + 21 + 20 = 97 s
P h e = 2.4 * (3600/97) * 0.85 * 0.7 = 53 m 3 / h
Removal of vegetable soil. The fertile soil layer, including the sod-vegetation layer, must be removed over the entire area occupied by embankments, excavations, reserves, quarries and other structures of the road complex. The boundaries in the plan, the thickness of the removal and the storage places of the soils of the fertile soil layer are determined by the project. Qualitative indicators and norms for the removal of the fertile soil layer are established by GOST 17.5.3.06-85.
Breakdown of works on soil removal consists in outlining the cut-off boundaries and contours of storage piles. To break down the boundaries of the cut, sticks with a height of 1.0-1.5 m are used, installed every 20-25 m. The contours of the storage shafts are designated with stakes; the cut boundary before the start of work - with a furrow (plow or ripper).
In order to prevent breakage or backfilling, the previously installed signs for taking out the project to the terrain should be protected with fences of three rails, fastened with the upper ends "in a tent", or marked with special poles. After the completion of the removal of the fertile soil layer, the breakdown established for this work is removed.
If the layer to be removed has high density or there are roots in it after the removal of the forest, before the start of cutting, the layer is loosened or plowed with multi-plow plows.
The fertile soil layer is removed, as a rule, in a thawed state. If the vehicles are difficult to pass, it is allowed to remove the soil in the spring when the soil thaws to the appropriate depth.
The fertile soil layer is cut off and moved to storage sites by bulldozers or motor graders, using the following work schemes:
when erecting embankments from imported soil, when the width of the strip from which the soil layer must be cut does not exceed 25 m, use shuttleschema lateral movement of soil in relation to the axis of the road;
when erecting embankments from lateral reserves or high embankments, as well as when developing deep excavations, when the road lane has a width of 30-40 m or more, cutting and moving the soil should be done first from one half of the strip, starting cutting from the axis, and then from its the other half, according to the so-called, transverse or transverse movement pattern;
with large volumes of work on removing the soil layer (thick layer, large width of the road lane), first, the soil is cut off with movement by a motor grader or a bulldozer with a rotary blade into the longitudinal shafts, from which the soil is later moved by bulldozers outside the road lane. In this case, the transverse movement of the soil at half the width of the road lane is carried out by oblique passes of the bulldozer (at an angle to the longitudinal axis of the road), so that at each pass, the full load of the bulldozer, corresponding to its power, is provided. Such a scheme is called longitudinal-transverse.
When removing soil from areas of large width, a scheme is used with the formation of shafts-stacks in the contour of the structure. Prior to the commencement of the next type of work, the soil must be transported to the storage areas established by the project by road transport with loading with forklifts.
With a vertical leveling of areas and strips with a grass cover wider than 50 m, it is allowed to collect soil into transverse shafts within the contour, followed by distribution along a planned seizure.
Soil stacks are placed taking into account the terrain and other local conditions with a strip width of up to 25 m, as a rule, on one side; with greater width - on both sides with gaps for the passage of construction vehicles, surface water runoff. In forests, arable lands and other valuable lands, soil storage is carried out on areas specially allocated for these purposes.
When removing, storing the fertile soil layer, measures must be taken to prevent its loss (erosion, swelling), as well as a decrease in its quality (mixing with underlying layers, roots, forest waste, pollution, etc.). With a storage period of more than a year, the surface of the soil shafts is strengthened by sowing grasses or in other ways provided for by the project.
The main activities for the preparation of the subgrade base. The prepared base surface must be bulldozed prior to embankment construction. Pits, trenches, pits and other local burials, in which water can stagnate, are filled layer by layer with compaction to the required density for the base (SNiP 2.05.02-85, Table 22). To ensure drainage in horizontal sections, a transverse slope from the axis is given not less than the coating established for the surface.
When using highly compressible non-draining soils as a base (peat, silt, low-density clay, etc.), and in the embankment - draining soils, when leveling, a building rise should be created in the middle part, the value of which should be greater than the design settlement of the base provided for by the project ...
Compaction of the soil base of low embankments and soil layers under the bottom of the working layer of the road pavement in excavations and zero places is carried out in the cases provided for by SNiP 2.05.02-85 and SNiP 3.06.03-85. The base soils are compacted immediately before the filling of the overlying soil layers or layers of pavement (airfield pavement).
If the required compaction depth exceeds the thickness of the layer effectively compacted with the applied means, the excess soil layer should be removed with a bulldozer and compaction of the underlying layer should be carried out. After compaction and leveling of the lower layer, the removed soil is returned and compacted to the required density.
When reconstructing roads using an existing embankment, vegetative soil is removed from the shoulders and slopes of the embankment being reconstructed and moved to the border of the right-of-way for subsequent reclamation. If it is impossible to use its biological properties, it is distributed in the base of the additional part. Before filling in additional layers, the surface of the old embankment should be loosened to a depth of 10-15 cm with compaction together with the next layer. The need to dismantle and remove layers of old pavement is established by the project.
Before starting work on the construction of the embankment, culverts and communication pipes, as a rule, must be completely completed and backfilled on both sides to a width of at least 4 m on each side, on top - with a layer of thickness not less than specified in the project, with layer-by-layer compaction to the required density ... At the same time, the movement and leveling of the soil, as well as compaction by rollers, is carried out by the longitudinal passes of the machines with respect to the pipe, while the embankment is built up on both sides. It is necessary to constantly monitor the approach of the machine to the pipe wall in order to avoid its shift or possible destruction. The thickness of the soil layer over the pipe, at which it is possible to compact the backfill soil and let the machines and transport pass through, must be indicated in the pipe project, but not less than that provided for by the current standards.
TYPICAL TECHNOLOGICAL CARD (TTK)
REMOVAL OF WEAK SOIL IN THE BASE OF THE FILL WITH A DRAINER REPLACEMENT
1 AREA OF USE
1.1. Typical routing(hereinafter referred to as the TTK) was developed for a set of works to remove soft soil (peat) at the base of the embankment of the roadbed road with its replacement with drainage soil in difficult soil-hydrological conditions, in areas with soils of low bearing capacity, attributed to bogs of types I and II.
Type I - swamps completely filled with peat, allowing the operation and movement of bog equipment with a specific pressure of 0.2-0.3 kgf / cm or the operation of conventional equipment using bed-type roads, which reduce the specific pressure on the surface of the deposit to 0.2 kgf /cm.
Type II - swamps completely filled with peat, allowing the work and movement of construction equipment only on temporary technological roads (stubble), providing a decrease in the specific pressure on the surface of the deposit to 0.1 kgf / cm.
Removal of soft soil (complete excavation) is carried out on a section of the road with a total length of 500 meters. Swamp type I, well decomposed peat, dense, layer thickness from 0.3 to 2.2 m. The soil of the mineral bottom of the bog is silty sandy loam.
1.2. A typical technological map is intended for use in the development of Projects for the production of works (PPR) and other organizational and technological documentation, as well as for the purpose of acquainting workers and engineering and technical workers with the rules for the production of work to remove soft soil (peat) at the base of the embankment of the roadbed of the highway with its replacement with drainage soil.
1.3. The purpose of creating the presented TTK is to give a recommended flow chart for the removal of soft soil (peat) at the base of an embankment of a roadbed of a highway with its replacement with drainage soil, the composition and content of the TTK, examples of filling out the necessary tables.
1.4. On the basis of the TTK, as part of the PPR (as mandatory components of the Project for the production of works), working flow charts are developed for the performance of certain types of work to remove soft soil (peat) at the base of the embankment of the roadbed of the highway with its replacement with drainage soil.
When linking a Typical technological map to a specific object and construction conditions, production schemes, volumes of work, labor costs, mechanization means, materials, equipment, etc. are specified.
1.5. All Working flow charts are developed according to the working drawings of the project, regulate the means of technological support and the rules for performing technological processes in the production of work.
1.6. Regulatory framework for the development of technological maps are: SNiP, SN, SP, GESN-2001 ENiR, production rates of consumption of materials, local progressive rates and prices, rates of labor costs, rates of consumption of material and technical resources.
1.7. Working flow charts are considered and approved as part of the PM by the head of the General Contractor for Construction and Installation Organization, in agreement with the Customer's organization, Customer's Technical Supervision and organizations in charge of the operation of this highway.
1.8. The use of TTK contributes to improving the organization of production, increasing labor productivity and its scientific organization, reducing costs, improving quality and reducing the duration of construction, safe performance of work, organization of rhythmic work, rational use of labor resources and machines, as well as reducing the time for development of PPR and unification of technological solutions ...
1.9. The bearing capacity of bog soils is very low, therefore special bog modernization machines are used for peeling, the pressure of which on the ground does not exceed 20-25 kPa. The technological map provides for the complete peeling of a type I swamp by a complex mechanized link with an ET-16 excavator having a widened and lengthened caterpillar track as a driving mechanism.
Fig. 1. Excavator ET-16
1.10. The composition of the works considered by the map includes:
Preparation of the strip for the device of a dry peat trench;
Arrangement of side lanes for the movement of the excavator;
Cutting off the vegetation layer of the soil at the approaches to the swamp, loading it onto dump trucks and transporting it for storage in the roadside reserve;
Complete removal of soft soil (arrangement of a peat trench) with development, loading, transportation and unloading to designated places;
Cleaning the mineral bottom of the excavation with a bulldozer after excavator operation;
Filling the trench with drainage soil, including quarrying, transporting, trenching, leveling and compaction.
1.11. Works are carried out in winter period year from December to March inclusive. The duration of the working time during the shift is:
where is the time associated with the preparation of the machine for work and ETO, as well as with breaks associated with the organization and technology of the production process, and breaks intended for rest and personal needs of the driver, 0.85
The duration of the work shift and lunch break.
1.12. Drainage soil from the near-trail reserve is represented by - group II 10 bulk weight 1.8 t / m sand, sandy loam, loam, 1.0 m / day, peat- Group I 37. Classification of soil corresponds to GESN-2001, Collection N 1 *.
* HESN 01 is in effect. - Note from the manufacturer of the database.
1.13. Work should be carried out in accordance with the requirements:
SNiP 3.01.01-85 *. Organization of construction production;
SNiP 3.01.03-84. Geodetic works in construction;
SNiP 3.06.03-85. Car roads;
SNiP 3.02.01-87. Earthen structures, foundations and foundations;
SNiP. Labor safety in construction. Part 1. General requirements;
SNiP. Labor safety in construction. Part 2. Construction production.
2. ORGANIZATION AND TECHNOLOGY OF WORK PERFORMANCE
2.1. In accordance with SNiP 3.01.01-85 * "Organization of construction production", prior to the commencement of construction and installation (including preparatory) work at the facility, the General Contractor is obliged to obtain, in accordance with the established procedure, permission from the Customer to conduct construction work (work order). Carrying out work without the specified permission is prohibited.
2.2. The implementation of work to replace the soft soil at the base of the embankment is preceded by a set of organizational and technical measures and preparatory work, such as:
Obtaining a permit for felling from forestry authorities (felling ticket);
Appointment of a person responsible for the quality and safe conduct of work;
Marking the boundaries of the right-of-way to be cleared;
Excavation boundaries marking;
Provision of workplaces with equipment, mechanized tools, devices brought to a state of technical readiness, as well as first aid equipment, drinking water, fire fighting equipment and personal protective equipment;
Instructing members of the teams on safety and industrial sanitation.
2.3. During preparatory work The contractor is obliged:
Accept from the Customer, no later than 10 days before the start of construction, a geodetic grid base in the amount of Chapter 9 of the joint venture .
After the design organization has completed the survey, the Contractor, in the presence of the Customer, carries out field acceptance of the land allotment strip, which is taken out and fixed with geodetic marks on the terrain. Acceptance and transfer of the assigned right-of-way is drawn up by an Act with the attachment to it of the necessary statements and magazines. The marks of the picketage intended for the construction of a linear structure and remote points are subject to random check. All points to be fixed and set out are entered into the route fastening scheme.
The customer transfers the following points and signs fixed on the ground outside the work area:
Borders of the right of way of land;
Planned signs of the route are fixed at least every 0.5 km;
Defining axis, start, end of alignment and intermediate points.
The customer also submits the following technical documentation:
Schemes for fixing the axis of the route on straight and curved sections, executed on the scale of the general construction plan;
Vedomosti: linear track measurements; fixing the route; benchmarks; rotation angles; lines and curves.
2.4. The procedure for the production of geodetic alignment works:
- mark the boundaries of the right-of-way (clearings).
The boundaries of the right-of-way are fixed on both sides of the road with gouges in the trees, and in open areas with poles and stakes. Stakes with a height of 50 cm measuring 7.0x5.0 cm, pillars with a height of 180 cm measuring 10x10 cm.From the pillars at a distance of 10-20 m (in alignment with the pillars), stakes with a height of 1.0 m are driven in, which indicate the height (H) along alignment axis, station number, distance to the alignment axis, location (left or right), benchmark elevation;
- visually hang the axis of the track.
First, the direction of the route is given with landmarks, then the stakeout correction is made and the points are fixed with stakes and leaders. Milestones with a height of 2.0-3.0 m are installed every 0.5-1.0 km on straight sections and after 5, 10 or 20 m on curves, depending on their radius;
- fix the picketage.
The pickets and plus points are fixed with pegs driven flush with the ground and 30 cm high gatehouses. The distance between the pegs and gatehouses is 15-20 cm;
- fix the angles of rotation.
The angles of rotation are fixed with four signs:
In the VU (place of the theodolite installation) with a column d = 10 cm driven flush with the ground;
At a distance of 2.0 m along the bisector from the VU, an angular identification post with a height of 0.5-0.75 m;
Two identification posts, the same height, outside of the forthcoming excavation work, on the extension of the sides of the corner, at the same distance.
2.5. Before the production of peat, the following work must be performed:
The road route has been restored and secured;
A site for soil replacement has been prepared;
Arranged entrances to the excavated trench and exits from it (at each seizure);
Turning platforms have been set up on the embankment;
Exits and platforms are arranged from imported soil at the same time as replacing the soil.
2.6. The scope of work to prepare the site for soil replacement includes:
Arrangement of temporary access roads and special sites for the location of equipment engaged in soil replacement work;
Clear the right-of-way from bushes and undergrowth;
Set the border of the removal of the vegetation layer;
Uproot stumps, remove felling residues and boulders;
Cut off the vegetation layer of the soil, load it onto dump trucks and take it out for storage in the roadside reserve;
Providing temporary surface drainage.
Work organization diagrams when peeling out by an excavator.
Fig. 2. With the movement of the excavator on the surface of the swamp
1 - development of peat with an excavator; 2 - transportation of soil by dump trucks; 3 - layer-by-layer leveling of the soil with a bulldozer; 5 - leveling peat removed from the trench by a bulldozer
Fig. 3. With the movement of the excavator along the dumped embankment
4 - pushing the soil into the trench with a bulldozer.
Roman numerals indicate the order of development of seizures
2.7. Work on replacing soft soil is performed on two grips. The size of the grapple is equal to half the width of the excavated trench. At the first capture, the following technological operations are performed:
Removal of soft soil to full depth;
Excavation of drainage ditches;
Replacement of weak soil with drainage.
2.8. To ensure the stability of the embankment, the removal of soft soil is carried out with a depth of 15-20 cm into the mineral bottom of the bog. peat in two longitudinal trenches.
The excavator performs the first and second grips in the "away" way from a solid surface of a non-marsh type, the excavator is installed no closer than 0.5 m from the edge of the excavated pit, the rest by transverse penetrations moving along the finished side strips, making peat to the full depth of the trench. In the process of trench development, natural freezing of the trench walls occurs, as a result, a dry trench is obtained. The peeling should be ahead of the dumping of the lower part of the embankment by three interchangeable grabs.
The cleaning of the mineral bottom of the developed pit is carried out bulldozer B 10M. B at the capture of at least 50 m, in two passes along the track, with the overlap of the previous pass by 0.5 m, thereby leveling the natural foundation under the embankment of the subgrade.
2.9. The developed peat is loaded into dump trucks VOLVO FMt) and taken out for temporary storage in designated places. Dump trucks, removing peat from the first three captures, move along the side strips. Then they can move along the bottom of the dug trench and filled with a layer of replacement soil.
In the future, peat can be used for cladding the slopes of the embankment of the subgrade when they are strengthened by sowing grasses.
2.10. Replacement soil is developed in the road reserve with a VOLVO EC-290V excavator and delivered to the work site dump trucks VOLVO FMм). The drainage soil delivered from the reserve is unloaded at a distance of 5 m from the edge of the trench. The dump truck turns on the embankment and backs up to the unloading point. After unloading the soil, dump trucks are installed at the peat loading site at an angle of 15-20 ° to the excavator passage axis.
Since the unloading of peat and the loading of the drainage soil are carried out in one place, a circular scheme of the operation of vehicles is used.
Reception of soil at the place of unloading is carried out by a road worker of the 3rd category. The worker gives a signal for the approach and departure of the car, regulates the movement of cars along the width of the embankment so that rutting is not created and a more uniform compaction of the layer is ensured.
2.11. The trench is backfilled with imported drainage soil. bulldozer B 10M.01 by the "head-on" method, that is, by pushing the soil into an open trench, in layers up to 1.0 m thick from the middle to the edges, by shuttle passes, followed by its leveling, to the level of the swamp. The bulldozer moves the soil in second gear to the edge of the excavation, gradually raising the bulldozer blade, pushes the soil into the excavation and, returning in reverse to the place of soil accumulation, levels the soil of the embankment with the bulldozer blade.
Leveling of the soil in the trench is carried out by the same bulldozer in four passes, with the movement of soil from the heap to a distance of up to 10 m in layers 1.0 m thick, according to the shuttle pattern from the edges to the middle for the entire width of the trench, with the overlap of the previous track by 0.5 m , at working speed in second gear.
The width of the layers of the replacement soil is equal to the width of the base under the embankment of the subgrade, erected above the level of the swamp.
2.12. The thickness of the deposited layers of replacing (draining) soil is taken depending on the soil roller used (see table 1).
Maximum thickness of the compacted layer (Ku = 0.95)
Table 1
|
Ice rink model |
Total weight, t |
Vibratory roller weight module, t |
Amplitude, |
frequency Hz |
Layer thickness (cm) |
||||
If there is a need to compact the soil to Ku = 0.98, reduce the thickness of the compacted layer by a third, reduce the working speed of the roller by a third and increase the number of passes by a third (n = 10-12).
When compaction of the layers indicated in the table to Ku = 0.95, the number of passes of the roller with strong vibration should be within 6-8, and the first two passes should be done with weak vibration or without vibration, at a working speed of 4-5 km / h.
Each of these rollers can perform its work on compaction in three modes - static (no vibration), with weak vibration (low amplitude) and with strong vibration (large amplitude).
2.13. Simultaneously with the development of the trench, drainage ditches are being developed with a width equal to the width of the excavator bucket, at a distance of 2.0-2.5 m from the bottom of the embankment.
Work on the development of the trench and its filling are carried out simultaneously within the framework of a single cycle, that is, immediately after its development, on the same shift. This should be done because the slopes of the trench being developed (1: 0.5) quickly float, filling the empty trench with water or liquid swamp mass.
2.14. On the second grip, the following technological operations are performed:
Working platform device;
Prior to compaction of the replacement layer;
Layout of the replacement soil layer.
2.15. Due to the large depth of peat and the significant thickness of the loose soil, the problem of its compaction is solved by using the largest and heaviest soil compaction machines of shock and vibration action. For this purpose, a self-propelled vibratory roller CA 602D weighing 18.6 t, capable of working through water-saturated sand to a depth of 100 cm with 6-8 passes along the track with the obligatory maintenance of the drum oscillation frequency of 25-27 Hz with the overlap of the previous track by the width of the roller drum, with the movement of the compaction strips from the edge of the layer to the axis. Each subsequent pass along the same track must be started after the previous passes have covered the entire width of the replacement layer. The first and last passes of the roller should be carried out at a speed of 2.5-3.5 km / h, intermediate at a speed of 8-10 km / h. The drainage layer should be compacted to 1.00.
2.16. Simultaneously with filling the trench, it is poured and leveled to the width of the embankment base, a working platform 0.5 m thick from the same soil. This platform will ensure the normal passage of construction vehicles over the peat area.
During the movement of dump trucks on the dumped platform, the lower part of the embankment is pre-compacted.
The lower part of the embankment with a height of 0.5 m above the level of the bog, taking into account the settlement, is not compacted with soil compaction equipment due to the fact that the embankment is poured from sandy soil, which is moistened from below and thus provides a good natural compaction.
After reaching the calculated settlement, the layer of replacement soil is compacted with a vibratory roller to the required density in six passes along the track, with the overlap of the previous track by the width of the roller of the roller, with the movement of the compaction strips from the edge of the layer to its axis.
The compaction of the layer is carried out in one stage, since a loaded vehicle moved along the dumped soil, and its directions were regulated, therefore, rolling the layer with a light roller is not required and the soil is immediately compacted to the required density with a heavy roller.
Each subsequent pass along the same track should be started after the previous passes have covered the entire width of the replacement layer.
The first and last passes of the roller should be carried out at a speed of 2.5-3.5 km / h, intermediate - at a speed of 8-10 km / h. The replacement layer should be compacted to 0.95-0.98. The number of passes of the roller along one track is accepted as six, but it can be specified by the manufacturer of the work in conjunction with the construction laboratory based on the results of test rolling.
Layout the surface of the embankment layer is performed with a motor grader after it has been compacted to the design degree of compaction, in four passes along the track.
The transverse slope of the surface of the layer should be equal to 40┐ and ensure the rapid removal of precipitated atmospheric precipitation.
The filling of the next layer for the construction of the subgrade can be done only after leveling and compaction of the replacing soil layer.
Fig. 4. Technological scheme for the removal of soft soil at the base of the embankment
2.17. Features of the production of work in the summer:
The lower part of the embankment is made of sand and poured into the water, filling the peat trench after reaching an elevation of 0.3-0.6 m above the water level in the swamp;
During peat removal, the excavator moves along the laid inventory boards(see Fig. 5) or plank flooring arranged along the top of the peat trench.
Fig. 5. Trench development scheme with a shale excavator
In case of insufficient stability of the excavator on the surface of the swamp, shields of round wood with a diameter of 16-22 cm are laid under the tracks. The area of the shield that ensures the stability of the excavator on the surface of the swamp can be determined by the formula:
where is the mass of the excavator, kg;
Bearing capacity of bog soil (14-18 kPa);
The lower part of the embankment with a height of 0.5 m above the level of the bog, taking into account the settlement, is not compacted with soil compaction equipment due to the fact that the embankment is poured from sandy soils, which are moistened from below and thereby ensure a good natural compaction;
Work on the development of the trench and its filling are carried out simultaneously within the framework of a single cycle, that is, immediately after its development, on the same shift. This should be done because the slopes of the trench being developed (1: 0.5) quickly float, filling the empty trench with water or a liquid swamp mass;
Simultaneously with the development of the trench, drainage ditches are being developed with a width equal to the width of the excavator bucket, at a distance of 2.0-2.5 m from the bottom of the embankment;
At the same time, a working platform with a thickness of 0.5-1.0 m is poured out of sand over the width of the embankment base, which ensures the passage of machines and layer-by-layer filling of the upper part of the embankment to the design height.
3. REQUIREMENTS FOR QUALITY AND ACCEPTANCE OF WORKS
3.1. Control and assessment of the quality of peat development work is carried out in accordance with the requirements of regulatory documents:
SNiP 3.02.01-87. Earthen structures, foundations and foundations;
SNiP 3.01.01-85 *. Organization of construction production;
SNiP 3.06.03-85. Car roads.
3.2. Quality control of the work performed should be carried out by specialists or special services equipped with technical means to ensure the necessary reliability and completeness of control and is assigned to the head of the production unit performing the peat work.
3.3. Drainage soils supplied to the site must meet the requirements of the relevant standards and working drawings.
Before the commencement of work on replacing the soil, the materials received at the facility must be subjected to an incoming inspection. Incoming inspection is carried out in order to identify deviations from these requirements.
Incoming control of the incoming sand is carried out by taking less than 10 spot samples (with a delivery volume of up to 350 m) of which they form a combined sample characterizing the controlled batch and conduct a laboratory check of such parameters as:
Grain composition of sand;
Content of dust and clay particles;
Clay content in lumps;
Class, fineness modulus, total residue on a sieve N 063;
Filtration coefficient.
The inert materials received at the facility must have an accompanying document (passport), which indicates the name of the material, batch number and amount of material, the content of harmful components and impurities, and the date of manufacture.
The results of the incoming control are drawn up by the Act and recorded in the Register of the incoming control of materials and structures.
3.4. In the process of peeling and replacing soil, it is necessary to carry out operational control of the quality of work. This will make it possible to identify defects in a timely manner and take measures to eliminate and prevent them. Control is carried out under the guidance of a foreman (foreman), in accordance with the Scheme operational control quality.
During operational (technological) control, it is necessary to check the compliance of the main production operations with the requirements established by building codes and regulations, the working draft and regulatory documents... Instrumental control of peat removal and soil replacement should be carried out systematically from the beginning to its full completion. In this case, the following should be checked:
Depth and width of the cut;
Samples of the mineral base of the bog;
Transverse slopes and evenness of the surface of the replacement layer;
The thickness of the replacement layer is based on one measurement per 2000 m, but not less than five measurements in any area;
The degree of soil compaction of the replacement layer;
Dimensions and cross-sections of drainage ditches.
When filling the replacement layer, it is not allowed:
Sand contamination during leveling and compaction;
Snow falling into sand.
The results of operational control must be recorded in the General Journal of Work.
3.5. Operational control is carried out in the course of production operations in order to ensure the timely detection of defects and the adoption of measures to eliminate and prevent them. The control is carried out under the guidance of a foreman, foreman.
3.6. The quality of work is ensured by meeting the requirements for compliance with the required technological sequence when performing interrelated work and technical control over the progress of work, set out in the Construction Organization Project and the Work Production Plan, as well as in the Scheme of Operational Quality Control of Work.
3.7. An example of filling out the Scheme of operational quality control of work is given in Table 2.
table 2
|
Name of operations subject to control |
The composition and scope of the control |
control |
Time spending |
Who controls |
|
Excavation device, filling of replacement drainage soil |
Peat depth Offset of the bottom axis in the plan ± 20 cm Distance from the axis to the edge of the pit ± 10 cm Height marks along the axis ± 50 mm Cross slopes ± 0.010┐; Width at the bottom and top ± 15 cm; Bottom compaction degree 0.98 |
Measuring, tape measure, level, density meter |
At least every 100 m at 3 points across |
Foreman Geodesist |
3.8. Acceptance of the road section, on which the soft soil at the base of the embankment has been replaced, is formalized by the Intermediate Acceptance Certificate of Critical Structures, in accordance with Appendix 7, SNiP 3.01.01-85 *.
3.9. At the construction site, it is necessary to keep a General Work Log, a Geodetic Control Log and an Author's Supervision Log of the design organization.
4. CALCULATION OF LABOR COSTS AND MACHINE TIME
7.2. Responsibility for the implementation of measures for safety, labor protection, industrial sanitation, fire and environmental safety rests with the work managers appointed by the order.
The responsible person carries out the organizational management of the work directly or through the foreman. The orders and instructions of the person in charge are binding on all soil replacement workers.
7.3. Labor protection of workers should be ensured by the administration of the necessary personal protective equipment (special clothing, footwear, etc.), the implementation of measures for the collective protection of workers (fences, lighting, ventilation, protective and safety devices and devices, etc.), sanitary premises and devices in accordance with applicable standards and the nature of the work performed. Workers must be created the necessary conditions labor, food and rest. The work is carried out in special footwear and overalls.
7.4. Terms of work, their sequence, the need for labor resources is established taking into account ensuring the safe conduct of work and the time for observing measures to ensure the safe performance of work, so that any of the operations performed does not constitute a source of industrial hazard for simultaneously performed or subsequent works.
7.5. When developing methods and sequence of work, hazardous areas arising in the course of work should be taken into account. If it is necessary to perform work in hazardous areas, measures must be taken to protect workers.
At the borders of hazardous areas, safety protective and signal fences, warning signs, clearly visible at any time of the day, must be installed.
7.6. Sanitary facilities, motorways and pedestrian roads should be located outside hazardous areas. A first aid kit with medicines, stretchers, fixing splints and other first aid equipment should be kept in the workers' resting trailer. All workers on the construction site must be provided with drinking water.
7.7. The person responsible for the safe performance of work is obliged to:
To acquaint the workers with the technological map against signature;
Monitor the good condition of tools, mechanisms and devices;
Explain to employees their responsibilities and the sequence of operations;
Stop work with a wind force of more than 11.0 m / s during heavy snowfall, heavy rain, fog or thunderstorms when visibility is less than 50 m.
7.8. Persons at the age of at least 18 years old who have passed:
Medical examination and found fit for work in construction;
Training and testing of knowledge on safe methods and techniques of work, fire safety, first aid and having a special certificate about this;
Introductory briefing on safety, industrial sanitation and instruction directly at the workplace.
Re-instruction is carried out at least once every three months. The briefing is recorded in a special journal.
7.9. The technical condition of the machines (reliability of fastening of units, serviceability of connections and working platforms) must be checked before the start of each shift.
Each car must be equipped with an audible alarm. Before putting it into operation, it is necessary to give a sound signal.
7.10. Before starting the machine, you must make sure that they are in good working order, that they have protective devices on them, that there are no unauthorized persons in the working area.
7.11. When operating several machines following each other, it is necessary to maintain a distance between them of at least 10 m.
7.12. Drivers are prohibited from:
Work on faulty mechanisms;
Eliminate malfunctions on the go, during work;
Leave the mechanism with the engine running;
Allow unauthorized persons to enter the mechanism cabin;
Stand in front of a disc with a locking ring when inflating tires;
To carry out work in the area of operation of cranes and power lines of any voltage.
7.13. When working with a bulldozer, the following rules must be observed:
When moving the soil with a bulldozer on the rise, it is necessary to ensure that the blade does not crash into the ground;
It is forbidden to move the soil uphill or downhill over 30 °;
It is forbidden to push the dozer blade over the edge of the slope when dumping soil down a slope;
It is forbidden to work in clay soils in rainy weather;
It is forbidden to stand between the tractor and the blade or under the tractor until the engine stops;
The blade should be lowered to the ground during accidental stops of the dozer.
7.14. When operating an excavator, the following rules must be observed:
It is forbidden to carry out any work and the presence of unauthorized persons within a radius equal to the length of the boom plus 5 m;
Leveling the excavator parking area is allowed only when it is stopped;
When the excavator is moving, the boom should be installed strictly along the axis of movement, and the bucket should be lowered to a height of no more than 0.5-0.7 m from the ground and pulled up to the boom;
It is prohibited to move the excavator with a filled bucket;
It is forbidden to hold (leave) the bucket suspended;
When the work is stopped, the excavator boom must be taken to the side of the face, and the bucket must be lowered to the ground;
The excavator driver is obliged to monitor the condition of the face and prevent the overhang of the soil layer (visor);
Outside of working hours, the excavator must be placed in a safe place, the cab is closed, the engine is turned off, the chassis and slewing parts are braked.
7.15. When operating the motor grader, the following requirements must be observed:
When turning the grader at the end of the profiled section, as well as on sharp turns, the movement should be carried out at the minimum speed;
It is necessary to level the soil on freshly dumped embankments with a height of more than 1.5 m under the supervision of a responsible person;
The distance between the edge of the roadbed and the outer (along the course) wheels of the motor grader must be at least 1.0 m;
Installation of the slope and extension, the removal of the knife to the side for cutting the slopes should be carried out by two workers in canvas gloves.
7.16. When working on soil compaction equipment, the following requirements must be observed:
The roller must be equipped with sound and signaling devices, the operability of which must be monitored by the driver;
On a freshly dumped embankment, the wheels of the roller should be no closer than 0.5 m from the edge of the slope;
The roller driver must wear protective clothing and goggles should be worn to protect the eyes from dust.
7.17. The minimum horizontal distance from the base of the slope of the trench being developed to the nearest machine supports should be 4.0 m.
7.18. Reverse feed of the dump truck to the place of unloading of the draining soil should be made by the driver only at the command of the road worker carrying out the acceptance of the soil.
8. TECHNICAL AND ECONOMIC INDICATORS
8.1. The numerical and professional composition of the complex brigade is - 22 people, including:
|
Excavator driver | |
|
Excavator driver | |
|
Bulldozer driver | |
|
Motor grader driver | |
|
Skating rink driver | |
|
Dump truck driver | |
|
Road worker |
8.2. Labor costs for mining are:
Labor costs of workers - 1578.60 man-hours.
Machine time on - 1240.83 machine-hours
8.3. Production per worker in a mining operation - 65m/ shift.
9. REFERENCES USED
9.1. When developing a Typical technological map, the following were used:
9.1.1. Technology and mechanization of construction production.
9.1.2. Reference book to SNiP "Development of projects for the organization of construction and projects for the production of work for industrial construction."
9.1.3. TSNIIOMTP. M., 1987. Guidelines for the development of standard technological maps in construction.
9.1.4. SNiP "Engineering surveys for construction. Basic provisions".
9.1.5. SNiP 3.01.03-84 "Geodetic works in construction".
9.1.6. SNiP 3.01.01-85 * "Organization of construction production".
Electronic text of the document
prepared by CJSC "Kodeks" and verified according to the materials,
If it is necessary to remove vegetative soil with an uneven and insignificant thickness (up to 10 cm) and move it to a distance of 50 m, it is advisable to use a motor grader (grader) for cutting the soil, and a bulldozer for moving. Vegetable soil is cut and placed in the shafts by a motor grader along the grapple. After the plant soil is laid in the shafts throughout the grapple, the bulldozer passes it across the grab to move it outside the grapple.
A bulldozer can carry out almost all technological processes for the removal, movement and registration of plant soil in the shafts. It is advisable to use a bulldozer with a distance of movement of the soil up to 50 m and a thickness of the vegetation layer of more than 10 cm.
In the presence of a flat area, cutting should be done at the most distant end of the site and the soil should be moved along the surface of the vegetation layer, which will exclude its mixing with the mineral soil.
With an uneven surface, it is advisable to make the first cutting closer to the place where the soil is laid in order to move the subsequent soil along the leveled surface in the trench formed by the previous cutting.
It is possible to remove plant soil with a thickness of more than 10 cm and move it at a distance of 50-500 m with scrapers. In this case, it is necessary to pay special attention to the fact that the mineral soil is not cut along with the plant soil with a scraper. If the thickness of the vegetative soil is up to 10 cm, it should first be cut off with motor graders and placed in rollers, after which the scrapers, moving along the rollers, collect soil.
The plant soil removed with scrapers can be laid in the prisms in layers. Having poured the first layer over the entire area of the base of the prism, proceed to pouring the second and subsequent layers from the edge of the prism to the middle with a deviation from the edge of the lower layer by an amount equal to 1.5-2.0 of the layer thickness.
When filling the prisms, it is necessary to ensure smooth entry and exit with a slope of no more than 1: 10 at their ends. The surface planning) of prisms and slopes is performed by bulldozers.
For a distance of more than 500 m, vegetative soil is advisable; move by dump trucks or tractor trailers. Loading of soil into vehicles should be carried out with grader-elevators with a thickness of vegetative soil more than 20 cm, or with excavators from prisms or heaps created by bulldozers.
The restoration of vegetative soil can be started only after the completion of work with mineral soil and careful planning of the surface of the excavation or embankment according to geodetic marks. When delivering soil by dump trucks or tractor trailers, it is advisable to level the soil with a bulldozer, and plan with a motor grader. In the absence of a bulldozer, the plant soil can be distributed from the heaps with a motor grader with the knife extended to the side to prevent the front wheels of the motor graders from colliding with the heaps, or use replacement equipment (mounted bulldozer), which some brands of motor graders are equipped with.
For ordering vegetative soil, light trailed rollers without ballast on pneumatic spikes or with smooth drums can be used.