Pipes

Protective separating layer of nanocm. Non-woven synthetic material (NCM)

MINISTRY OF COMMUNICATIONS OF THE USSR

MAIN WAY DIRECTION

TECHNICAL INSTRUCTIONS FOR THE APPLICATION OF NON-WOVEN MATERIALS TO REINFORCEMENT THE GROUND LINE

CPU-4591

Moscow "Transport" 1989

The Technical Instructions set out the requirements for the design and calculation of anti-deformation structures made of non-woven material, laid to eliminate track subsidence, intense rail gauge disturbances, slope slides, as well as to prevent the formation of ballast troughs and beds on the main subgrade area and erosion. The main provisions on the organization and technology of work in the construction of these structures are given. For engineering and technical workers of the track facilities.

Responsible for the release of P.I. Dydyshko, V.V. Sokolov

Head of editorial V.G. Peshkov

Editor L.P. Topolnitskaya

INTRODUCTION

Stability railway track largely depends on the subgrade, which is composed of clay soils for about 70% of its length. Under the combined influence of a moving load and climatic factors, the subgrade in these places is unevenly deformed. The main platform (the interface between ballast materials and clay soils) is often affected by ballast troughs and stocks. As a rule, the intensity of track disturbances in terms of level and profile in these sections is increased. In some cases (approximately 1% of the total network length), track subsidence occurs, which is accompanied by uneven subsidence and shifts of the rail gauge, liquefaction of clay soil with splashes from under the sleepers, extrusion masses of this soil on the surface of the ballast prism. They increase when the soil thaws and rains fall. Under favorable engineering and geological conditions, deformations of the under-rail foundation can manifest themselves in places of increased dynamic impact of a moving load (turnouts, equalizing spans of a seamless track, etc.), as well as in heavily clogged areas,

IN modern conditions operation, the possibility of providing "windows" in the movement of trains to perform work to strengthen the subgrade and the track as a whole with high traffic density is limited. This makes it necessary to reduce the volume of dugout work to the maximum extent and to switch to the use of artificial materials with the necessary properties in anti-deformation structures.

For thermal insulation, foam plastic is used, which prevents seasonal freezing - thawing of clay soils, for hydraulic insulation - a polymer film that prevents infiltration of precipitation. Thermal and waterproofing coatings are laid within the ballast prism. The requirements for their installation are set out in the Technical Instructions for Eliminating the Causes and Drawdowns of the Railway Track, TsP/4369.

Non-woven synthetic material, which is currently finding more and more wide application during the construction and operation of facilities for various purposes in our country and abroad, is able to divide and reinforce soils, drain and divert water. This material is made from synthetic fibers (waste, recycled raw materials or primary from polymer melt), which are mechanically interconnected on needle-punching machines, where special needles entangle them in a layer. For the production of materials, fibers from various polymers (polyester, polyamide, polypropylene, etc.) are used, the chemical and biological resistance of which ensures their service life in the soil for several decades. The use of natural fibers is excluded, as they are short-lived when working in the ground.

The most important properties of nonwoven materials include the following:

the ability to retain small particles of soil (filter property);

high water permeability;

high mechanical tensile strength combined with elasticity and elongation;

manufacturability of application (low consumption per unit area, ease of transportation, installation and connection).

Possessing the specified set of properties, the nonwoven material performs one of its functions - the role separating layer. The stress-strain state of the soil, formed under the combined influence of loads and climatic factors, changes after laying the non-woven material. This layer prevents the manifestation of residual deformations of the soil, since the freedom of movement of individual particles is limited, They cannot pass through the material. This prevents the interpenetration of large particles into the clay soil and small particles into the draining soil. The shift of individual layers, aggregates or soil particles in the zone of the interlayer is difficult.

Reinforcing function material lies in the fact that it is able to withstand tensile forces and increase the bearing capacity of the soil base reinforced with this material. In this case, the stresses in the soil mass are redistributed. The interlayer, working as a membrane, transfers some of the stresses, leveling them to a certain extent, from more loaded places to less loaded ones.

Cast return filter the material prevents mechanical suffusion, i.e. removal of small soil particles by water flow. At the same time, in the direction of water movement in front of the layer of non-woven material, as a result of re-sorting of particles, an additional natural soil return filter is formed.

Work of nonwoven fabric as drainage layer(drainage function) is possible due to its high water permeability along the web. For example, when a material is located on a soil with a low filtration coefficient, the flow of infiltrating sediments, having reached a layer of this material, will begin to move along it. Some of the water will go down into the ground, but some of it will change its movement in the direction of less resistance and be diverted away from the ground in need of protection.

These functions are manifested, depending on the type of deformities to be eliminated, separately or, which occurs most often, together.

Non-woven material is used to eliminate and prevent subsidence of the track, intense disorders of the rail gauge, slope slopes of embankments and cuts, erosion of flooded slopes, uneven settlement of embankments in swamps, siltation of drainages for various purposes, etc. In some cases, this material is used in combination with waterproofing film.

Part of the deformations practically or cannot be eliminated without the use of non-woven materials, or their elimination requires significant labor and material costs, as well as long breaks in the movement of trains. Such deformations include subsidence of the track with extrusion of liquefied soil onto the surface of the ballast prism, slope slips during surface waterlogging, soil washing out from under the slabs of the bank protection structures and flooded embankments, etc. Nonwoven material is indispensable in those structures where, when using draining soil, work with high, often difficult to achieve accuracy (installation of a return filter in drainage and other structures).

The use of non-woven material coatings instead of traditional designs reduces the cost of eliminating and preventing deformations. At the same time, labor costs are reduced for the maintenance of the subgrade and the track as a whole, its overhaul or construction, the throughput of lines increases, significant savings in money are achieved.

These Technical Instructions contain the main provisions for obtaining initial data for design, the conditions for the use of nonwoven materials, the necessary requirements and recommendations for the installation of anti-deformation structures made of these materials, as well as the organization and technology of work.

The guidelines have been developed on the basis of the results of experimental and pilot-production use of non-woven material on railways, analysis of foreign experience, laboratory tests and calculations.

The technical guidelines were developed by VNIIZhT, KhabiIIZhT, HIIT, VNII Transport Construction together with the Main Department of Railways of the Ministry of Railways and the Northern Railway.

1. GENERAL PROVISIONS

1.1. These Technical Instructions are intended for use by employees of services and track distances, track machine stations, engineering and geological bases and track survey stations, design organizations and construction departments in the appointment, design and implementation of measures to strengthen the sub-rail base and other elements of the railway subgrade using non-woven materials .

Work to eliminate intense disorders of the rail gauge in terms of level and profile using non-woven material is envisaged in projects for major and medium track repairs. The repair estimate documentation includes the specified works. The feasibility of application and specific areas for laying non-woven material are established on the basis of operational data on the state of the track, labor costs for its maintenance, rail outlet, wear of elements of the upper structure and other indicators.

Together with the laying of non-woven material, the projects provide for the reconstruction or construction of new drainage systems to ensure the runoff of infiltrating precipitation from the coating of non-woven material,

1.4. The laying of coatings from non-woven material is performed as an independent work or in conjunction with a major (medium) repair of the track, providing for maximum mechanization using track, general construction earthmoving and special machines designed to repair the subgrade. The work is carried out by the forces of track machine stations, including specialized ones, individual specialized columns of these stations and teams of track distances.

1.5. The purpose of coatings made of non-woven material should be justified by a technical and economic comparison with other methods for eliminating subgrade deformations and strengthening the under-rail foundation (planning of the main site, waterproofing coating, etc.).

1.6. The main characteristics and location of the laid coatings made of non-woven material, as well as the change in the nature and size of deformations after laying, are reflected in the established order in the relevant forms of technical passports for track distances.

2. INITIAL DATA FOR DESIGN

2.1. The initial data for the design of anti-deformation structures using non-woven material on operating lines is obtained during an engineering and geological survey, which is carried out on the basis of the terms of reference of the track service.

2.2. During an engineering-geological survey to develop a project to eliminate deformations of the under-rail foundation (track subsidence, intense rail track disturbances in level and profile on an unstable subgrade, uneven heaving of homogeneous soils), the site is inspected, fixed characteristics deformations and make instrumental shooting. By drilling, digging or pits with sampling, the composition, composition and condition of the subgrade soils are determined. At the same time, at least five points of the under-rail foundation (along the axis of the track, under both rails from their outer side and at a distance of 20-40 cm from the ends of the sleepers) in the sleeper box and under the sleeper, the configuration of the clay soil surface on the main platform of the subgrade is established. Determine the presence and depth of location ground water, sources of local soil moisture and other hydrogeological conditions, The required volumes and procedure for conducting an engineering-geological survey are established in accordance with the requirements of the Technical Instructions for the Elimination of Heaves and Drawdowns of the Railway Track, TsP / 4369.

3.2. To reinforce the subgrade, non-woven material is used, which must meet the following requirements:

Strip width, mm	over 1700
Thickness, mm
Weight 1 m 2, g	" 500
Breaking load, kgf, for a strip 5 cm wide in the direction:
longitudinal	" 60
transverse	" 30
Elongation at break, %, in direction:
longitudinal	less than 80
transverse	" 140
Water permeability (filtration coefficient), m/day.	over 10

3.3. In anti-deformation structures of the railway subgrade, it is possible to use a non-woven material that meets the above requirements, manufactured according to the specifications "Needle-punched fabric for road construction - dornit. Specifications" TU 21-29-81-81, type 1, which is intended for elevated roads bearing capacity. The use of type 2 and 3 material to reinforce the railway subgrade is not permitted.

In addition, it is allowed to use non-woven materials produced according to other specifications, including imported, if they meet the above requirements, as well as non-woven fabrics worked out at chemical fiber factories for filtering viscose solutions, washed and sewn into strips.

The non-woven material is placed at a depth of at least 0.2 m below the base of the sleepers ( δ n) on the surface of ballast materials cut off and planned with a slope of at least 0.04 to the field side.

If the distance from the top of the ballast prism to the main area of the subgrade of sandy loam and loam with a yield boundary w L

The coating is laid across the entire width of the subgrade on top. On double-track sections, in the absence of deformations on the adjacent track, it is possible to cover only one track.

Rice. 2. Schemes for laying a coating of non-woven material when eliminating subsidence of the track and disorders of the rail gauge in terms of level and profile on unstable sections of the subgrade in the recesses:

but- on a single-track line; b, c- on a double-track line for one track and two tracks; 1 - non-woven material; 2 - ballast; 3 - clay soils; 4 - drainage; 5 - tray

The pavement to eliminate subsidence of the track and disorders of the rail gauge under the turnouts must be of variable width. The edges of the coating are located behind the ends of the transfer bars by at least 0.9 m (). It is laid 0.2 m below the sole of the bars with a slope of at least 0.02.

When arranging a coating under the turnouts and on the station tracks along it, a shallow drainage is laid along the inter-track with a longitudinal slope of at least 0.03, the release of which is carried out by transverse drainage (see). To do this, use pipe filters or a "deaf" drain with a diameter of at least 15 cm, which is made of crushed stone wrapped in non-woven material. The bottom of the drain must be below the edge of the cover.

In a similar way, if necessary, water is drained from the inter-track on the hauls in curved sections of the track.

When crushed stone of ordinary size is used in the ballast layer, a layer of sand, asbestos ballast or fine crushed stone of a fraction of 10-25 mm with a thickness of 5-10 cm is laid on the non-woven material.

Separate strips of non-woven material in the coating, when eliminating subsidence of the track, are placed across the track, i.e., the length of these strips should be equal to the width of the cover. The strips must overlap each other by at least 0.2 m. When eliminating rail track disorders in terms of level and profile on unstable sections of the subgrade, it is allowed to place strips of non-woven material along the track with a mutual overlap of at least 0.2 m.

In difficult engineering-geological conditions, with intense manifestation of subsidence of the track with extrusion of liquefied soil through the ballast, the non-woven material in the coating can be laid in two layers. In this case, crushed stone of normal size can be directly laid on the non-woven material.

5. ELIMINATION OF RAIL TRACK DISORDERS IN THE LEVEL AND IN THE PROFILE WITH THE FORMATION OF SPLASHES IN COLLECTED AREAS

5.1. The non-woven material is placed within the ballast prism at a depth of at least 20 cm from the base of the sleepers (Fig. 5, but).

Under a layer of non-woven material, crushed stone must be cleaned of weeds to a depth of at least 10 cm in order to ensure the most complete and rapid removal of infectious moisture into this layer. Laying of non-woven material on unplanned rollers of cleaned crushed stone in under-rail sections, remaining after the operation of the ballast cleaning machine, is not allowed. This surface must be level.

In areas with a stable subgrade, in which rail track disorders in level and profile with the formation of splashes occur due to weeds, a continuous coating is arranged; at the same time, in some justified cases, it is allowed to cover only under the joints, and in sections of the continuous track - under the leveling spans. On turnouts, it is allowed to lay the material in the areas of the cross and the frame rail, which are most subject to dynamic action from a moving load. The edges of the coating must be separated from the joints by at least 2 m.

To drain water in the transverse direction, a layer of non-woven material is brought on hauls to the slope of the ballast prism, and on station tracks and turnouts - to shallow drainage. This drainage is arranged in accordance with the requirements.

5.4. The pavement within the abutments of bridges, as well as the spans of reinforced concrete bridges with a ride on ballast, is laid at the depth indicated above, bringing to the sides of the ballast troughs (back walls of the abutments). Longitudinal water drainage is carried out with the help of drains, which are placed along these sides. In this case, drains can be made of non-woven material, which is rolled up from a strip about 1 m wide.

6. APPLICATION OF NON-WOVEN COATING AND WATERPROOFING FILM

The conditions for the use of this coating are set out in. Uneven heaving with homogeneous soils manifests itself in this case as a result of ongoing (or ongoing) subsidence of the track. The ballast troughs and beds that arose during these drawdowns different depth lead to increased uneven moistening of cohesive soils that are infiltrated with moisture. Non-woven material due to its properties cannot be used independently to eliminate the causes. It is used for this purpose in conjunction with a waterproofing film that traps infiltrating precipitation.

The design of the coating of non-woven material and waterproofing film to eliminate heaves under the conditions under consideration is performed in accordance with the requirements set forth in.

7. ELIMINATION OF SLIDES AND TRACK SETTLEMENTS ON UNSTABLE EMBRACES ON A SOLID FOUNDATION

7.1. On unstable areas of embankments, a coating of non-woven material or a combined coating of non-woven material and a waterproofing film is laid, depending on the nature of the manifestation of deformations.

Finding values Qi. We determine by known methods by solving the inverse problem the parameters c i And φi, which correspond to the limit equilibrium condition of this uncovered slope. For this case, as a result of the solution, the parameters c i\u003d 0.7 tf / m 2 and φi=8°.

Let's calculate the stability of a slope with a coating. Accept fromin\u003d 0.14ts / m 2, φin=36°. The thickness of the layer of drainage soil over the non-woven fabric is 0.1 m. Angle β cf=27°. Values Qin we find for the density of the draining soil equal to 2 t / m 3.

We perform the calculation according to the formula ().

Initially, we calculate the parameter included in the formula ()

ts;

ts.

Given that fromi\u003d 0.7 tf / m 2, φi=8°, we find

Thus, with these parameters fromin\u003d 0.14 tf / m 2 and φin=36° the required value of the stability coefficient is reached TO " = 1,2.

Gaps and cracks on the surface of the slope are sealed with a homogeneous soil, tamping it down. Depressions in which water can stagnate are eliminated by leveling and backfilling with local soil with tamping. If necessary, perform partial cutting and cleaning of the soil in the places of uplifts, as well as in the lower part of the arrays that have floated earlier. To increase the adhesion of the non-woven material to the underlying soil, the grass on the slope is mowed, surface loosening is performed manually, or a thin layer of crushed stone is poured, ramming it.

To prevent slipping of the draining soil between two layers of non-woven material, in this case, it is possible to lay the triangular grid described above or to arrange cages from stakes and poles. The top layer of non-woven material is put on the stakes through cuts made in it.

When arranging a non-woven material cover in combination with a counter-banquet to increase the stability of the slope, in the upper part of the embankment, the structure is made in accordance with the diagram shown in . Water drainage in the lower part of the cover is carried out by a longitudinal closed drainage, constructed in the upper part of the counter-banquet. Drainage can be made of crushed stone wrapped in non-woven material, under the bottom of which a waterproofing film is laid in the form of a gutter. Longitudinal slope is provided not less than 0.01.

The size of the counter-banquet in this case can be reduced according to the results of the calculation using the above methodology.

Strips of non-woven material in the cover are placed perpendicular to the axis of the path with an overlap, the size of which is set in accordance with the above calculation method, but not less than 0.2 m.

In the coating from top to bottom there should be a single strip without extension. The strips are welded together on a slope with a blowtorch with a continuous seam or sewn with nylon threads using a machine. Under the ballast prism, the strips may not be connected.

Before joining, the strips are pre-stretched by applying a load uniformly distributed over the width of the strip equal to 20% of the breaking load in the longitudinal direction. Methods for applying the load and changing the size of the strips are established for these conditions by testing.

7.7. In difficult local conditions, including the manifestation of settlement of the track and slopes of embankments in the area of culverts, in a pilot production order, the anchoring of the coating from non-woven materials in the upper part is carried out in accordance with the scheme without laying the coating under the rail and sleeper grid. The material is wrapped through reinforced concrete beams laid on the side of the road, which abut against the beams placed on the slope across the track axis. It is pinched due to the subsequent surcharge from above. The length of the pinched part is determined by calculation.

In order to ensure their stability when working in compression under the action of shear forces, the transverse bars are made of reinforced concrete with a section of 0.2 x 0.2 m on site or assembled from old-fashioned reinforced concrete sleepers, connecting them rigidly to each other. In the latter case, the sleepers are laid on their side, facing each other with beds, and pulled together with two bolts with a diameter of 22 mm through through holes. To ensure the desired overall length transverse bars at one end, the sleepers are interconnected with clamps. Across the rows of these beams, leaning on them, prefabricated beams (old-year reinforced concrete sleepers) are laid.

The lattice of bars outside the culvert is held by stops. The design and dimensions of the stops are determined by calculation. Above the pipe head, the grating rests on a beam placed parallel to the track axis and monolithic for joint operation with transverse beams.

Strips of non-woven material are connected to each other in the manner described above (see), after stretching them. To increase the holding forces, the non-woven material can be "sewn" to the ground at the joints of the strips with stakes 1-1.5 m long every 1.2 m. In this case, welding or stitching of the strips is not required.

The coating on the slope is covered from above with a layer of draining soil, the thickness of which is set in accordance with the above calculation (see).

7.8. Anchoring of the coating in the upper part of the embankment outside the culvert on a potentially unstable section of the slope can also be carried out in accordance with the scheme.

The procedure for performing work during the installation of the coating is set out in these Instructions.

8. ELIMINATION AND PREVENTION OF DEFORMATIONS OF SLOPES OF CUTTINGS

8.1. Non-woven material is used both to prevent possible mixing of soil on slopes, and to stop the further development of already manifested deformations. Laying non-woven material on a slope is allowed at a depth of development of deformations that does not exceed the maximum depth of soil freezing in a 10-year period.

Non-woven material is used for all types of clay soil, characterized by moisture along the yield line wL≤0,45.

The coating, passing water through itself and retaining soil particles, acts as a return filter on slopes, including when groundwater exits here. As a result, washouts and sinks of the soil stop. In addition, the stability of the slopes is increased due to the additional holding forces that arise.

8.2. The calculation of the stability of the slope of the excavation is performed according to the methodology set forth in these Guidelines. The calculation determines the required number of layers of non-woven material of a given strength, the thickness of the draining soil layer over the non-woven material, and the parameters of the pinching of the coating in the post-slope part of the excavation.

8.3. Before laying the material, the cracks between the floating massifs are filled with local soil and the depressions on the slope are eliminated. If necessary, partially remove the soil in the lower part of the floating arrays. At the same time, it should be taken into account that this part is supportive and its excessive removal will lead to a violation of the existing balance of the slope, therefore, when harvesting, it is enough to ensure the normal operation of the drainage systems in the excavation.

8.4. A non-woven material is laid on the slope prepared in this way in the area of deformations and beyond it at least 10 m in each direction along the entire height. The coating in the upper part is led from the edge to the field side by a value of at least 2 m (Fig. 11, but). In the lower part, if necessary, cover the cuvette shelf with material and line the cuvette. The material must be "sewn" to the slope with stakes. The length of the stakes driven into the ground through cuts in the material should be 1.2-1.5 m. They do not reach the end by 0.1-0.2 m. They are placed from each other at a distance of at least 1 m.

non-monolithic prefabricated concrete slabs with dimensions of 1x1 m or reinforced concrete slabs with dimensions of 3x2.5 m with flexible ties on a layer of crushed stone 10 cm placed over non-woven material ();

prefabricated reinforced concrete slabs measuring 3x2.5 m with drainage holes, monolithic along the contour with a TsNIIS dowel, on non-woven material ().

9.3. If the slopes are composed of clayey sands, sandy loams, loams or clays, then for all these types of coatings, a layer of sand 10 cm thick is required between the slope soil and non-woven material. The fractional composition of the layer is selected in accordance with the requirements of SNiP II -53-73 "Dams from local materials ".

9.8. The consequences of erosion on operated lines are eliminated using non-woven material (). The erosion funnel is filled with local soil or stone. Non-woven material covers the entire area of erosion with a margin for the depth of general erosion and is pressed by rockfill, concrete blocks and other materials.

When the slope of the mineral bottom of the swamp is up to 1:5, work on laying the soil on both sides of the embankment is carried out simultaneously both during the construction of the field parts of the berms and when filling the space between the field parts and the embankment of the sinuses. With a greater steepness of the slope, in order to avoid shifting the embankment, a berm is first constructed from the downstream side. The sinuses are filled after the sinking of the berms into the swamp slows down or stops abruptly.

The non-woven material is laid in two layers: in the transverse and longitudinal directions. At the same time, a margin of width is provided on the field side of the berm and on the slope of the existing embankment to compensate for the ongoing change in the size and shape of the coating when it is immersed in a swamp under the weight of the dumped soil. The size of the margin on each side should be taken equal to 1.5 N bol. Strips of non-woven material in both layers overlap each other by at least 0.2 m. They are welded or sewn with a continuous seam.

10.2. For embankments erected on a weak foundation, significant deformations are characteristic. The embankments not only settle into the ground, but also spread to the sides, and the deformations during operation continue without fading for a long time.

The nonwoven material does not prevent soil consolidation. However, its use in the construction of embankments on weak foundations in difficult engineering and geological conditions makes it possible to obtain: uniform subsidence of the soil base; preservation of the design outlines of the embankment and prevention of spreading and uplift of the base; reduction of soil dumping by reducing the settlement of the embankment and base during operation and maintaining the interface between the soils without their interpenetration.

Rice. 16. Scheme of layer-by-layer backfilling of surcharge berms during stabilization of embankments in swamps:

1 - existing embankment: 2 - field part of the berm; 3 - non-woven material;

I - VII - the sequence of laying the soil in the berms

10.3. Non-woven material is used in type I swamps with a peat deposit thickness of up to 1.5 m and on a base represented by silty and peaty soils, including marshes. In addition, it is used on the basis of waterlogged clay soils ( I L>0.5) under embankments up to 1 m high in the zone of high-temperature permafrost.

10.4. When preparing the base for laying non-woven material, bushes are cut down, trees are cut down, the coating is placed on the entire width of the embankment below. The number of layers of non-woven material under the embankment should be selected from the condition that their total tensile strength is not less than 1.5 tf/m for an embankment height of up to 2 m and not less than 2 tf/m for an embankment height of 2 to 4 m.

Strips of non-woven material are laid on the base in the direction transverse to the axis of the path, connecting them in accordance with the requirements. Backfilling of the soil before creating a layer of 0.5 m above the non-woven material is carried out using the "from the head" method.

10.5. When using non-woven material at the base of the embankment, berms are not satisfied with mari. The work is carried out without damaging the moss-peat cover, including in warm time years, without waiting for the freezing of the active layer.

11. APPLICATION OF NON-WOVEN MATERIAL IN DRAINAGES

11.1. Non-woven material as a return filter in drainages is used in accordance with the schemes of Fig. 17. Drainages are arranged in combination with anti-deformation structures for various purposes: anti-heaving cushions, heat and waterproof layers, non-woven material coatings or combined coatings on the main site, embankment slopes, etc. In addition, closed drainages with a return filter made of non-woven material they are constructed to improve drainage conditions in excavations, including flooded ones, under "buried" ditches, on turnout necks to drain water from switch drives, when arranging a transverse water outlet at stations, double-track and multi-track lines.

11.2. "Deaf" drains (Fig. 17, but) is performed by wrapping crushed stone from slightly weathered rocks with a particle size of more than 40 mm with a non-woven material. The diameter of this drain is taken at least 20 cm. When using perforated pipes or pipe filters according to the schemes of Fig. 17, b, in for backfilling, medium and coarse-grained sand is provided. The material for filling the trench above the closed drainage is selected based on the conditions of its operation. To prevent mechanical suffusion of soil behind the walls and under the bottom of flumes constructed in difficult hydrogeological conditions, it is advisable to additionally lay a layer of non-woven material (Fig. 17, G), which will act as an inverse filter.

Rice. 17 . Schemes of drainage devices with a return filter made of non-woven material:

a - "deaf" drain; b - pipe with draining backfill; in - "pipe in a shell"; g - a tray with an external filter; 1 - backfilling of the trench; 2 - non-woven material; 3 - crushed stone; 4 - draining material; 5 - perforated pipe; 6 - tray

12. PROTECTIVE LAYER FROM NON-WOVEN MATERIAL ON THE MAIN AREA OF THE GROUND PLATE

12.1. protective layer from non-woven material on the main platform of the subgrade is laid to reinforce the path when installing mortise pads and laying out this site in accordance with the Technical Instructions CPU/4369. It increases the bearing capacity of the soil, prevents the formation of ballast troughs and beds, subsidence of the track and uneven heaving.

12.2. Non-woven material should be used in recesses, at zero places and embankments with clay soils of all types, with the exception of sandy loam containing sand particles ranging in size from 2 to 0.05 mm in an amount of more than 50% by weight. For clay soils with moisture at the yield limit wL>0.23, as well as with increased natural moisture content of clay soils characterized by wL≤ 0.23 and flow rate I L>0.25, a draining pad must be laid over the nonwoven material.

12.3. The thickness of the drainage pad h h should be assigned in accordance with the table. 3 and 4 depending on: the type of soil (moisture at the yield point wL) and freezing depth h pr to according to the table. 3; on the state of the soil (fluidity index I L) according to the table. 4. At the same time, for soils with wL≥0.23, the larger of the values given in Tables 3 and 4 is taken.

12.4. A diagram of the construction of a subgrade with a drainage pad on top of a non-woven material is shown in. The surface of clay soil on single- and double-track lines is planned on both sides of the subgrade axis with a slope of 0.04.

Table 3. Draining pad thickness

Soil moisture at the yield point w L	Meaning h h along the axis of the path, cm, at the depth of freezing h pr, m
Soil moisture at the yield point w L	UP TO 1.5	1,5-2	2-2,5
0,23-0,35
0,36-0,40
0,41-0,45
0,46-0, 50
0,51-0,55

Table 4 Draining pad thickness

Rice. eighteen. Scheme of subgrade construction with non-woven fabric and drainage pad:

but- in the embankment; b- in the recess; 1 - crushed stone; 2 - ballast cushion; 3 - drainage pillow; 4 - non-woven material

12.5. For the construction of the cushion, it is necessary to use sands, with the exception of silty, coarse-grained soils (with a maximum particle size of 300 mm) or coarse-grained soils with sandy aggregate.

13.2. On the basis of standard technological processes, repair units (in some cases, design organizations) draw up a working technological process for the production of works. To determine the labor costs, the list of machines and mechanisms, to clarify the scope of work, it is necessary to use technological processes No. 5-9 for the installation of mortise anti-flood cushions and overhaul of the track with the layout of the main subgrade area, which are included in the technological processes for overhaul of the subgrade of the railway track, as well as technological track overhaul processes with lowering or maintaining longitudinal profile marks.

13.3. Work on laying non-woven material is divided into preparatory main and final.

13.4. During preparatory work outline the boundaries of the under-rail base soil cutting and fix the sections of the beginning and end of laying the coating and the boundaries of the outlets. To do this, make marks on the adjacent path or hammer pegs to the side.

To ensure the normal operation of the machines, the preparation of the site includes: removal of obstacles that can cause a stop or damage to the machines, removal of paving, soil and flooring at crossings, preparation of places for driving onto and leaving the track for earthmoving equipment.

In accordance with the project, individual strips of material are measured and cut, taking into account their overlap in the longitudinal and transverse directions. Prepared strips are wound into separate rolls, which are laid out within the front of work.

To reduce the volume of crushed stone to be cut by earth-moving machines into the main "window", a side cutting of the shoulder of the ballast prism is made with the ballast dump beyond the curb. Before cutting the ballast, a place is prepared for its placement outside the gauge: the ditch is cleared of vegetation, and stagnant places are eliminated. To drain water, drain pipe filters or "blind" drains made of crushed stone wrapped in non-woven material are laid at the bottom of the cuvette. To reduce the volume of cut crushed stone placed in the recess, part of the crushed stone is cut out by the SHOM-4 machine, followed by its removal by the SM-2 machine.

When using the old lattice during the preparatory work, new sleepers are imported and the unusable ones are replaced, the bolts are tested in the joints, and the sleepers are fixed by finishing with crutches.

Before starting the main work, with the help of levels installed for the entire period of the "window", the existing marks of the top of the sleepers along the axis of the track are taken in sections fixed at 10 m in order to control the design marks during cutting the soil and laying the foundation.

13.5. The main works include: dismantling the rail-sleeper grid, cutting the soil, laying out the base of the coating and bends, spreading the strips of non-woven material, laying the rail-sleeper grid, ballasting, raising and straightening the track.

If the laying of non-woven material on the main platform of the subgrade is carried out as an independent work, then the rail-sleeper grid is disassembled and laid with one track-laying crane. In this case, depending on the conditions for the placement of work trains, the possibility of skipping the maximum train flow during the execution of work and other factors, either the reverse order of the formation of work trains is adopted, i.e., the straightening and tamping machine is sent to the stage first, then the ballast, the composition of hoppers-dispensers , a track-laying train, or a rail-sleeper grid is disassembled by a track-laying machine in the opposite direction, starting from the end of the section.

When laying non-woven material in combination with a major overhaul of the track structure, the procedure for the formation of working trains and the performance of work is determined by standard technological processes.

To facilitate the operation of the laying crane, the rail and sleeper grid is torn off from the ballast prism before disassembly with an electric ballast, a gravel cleaning machine or a VPO-3000 machine. At the end of the work, the SHOM machine, as well as the track plow that has completed the preliminary side cutting, are overtaken along the adjacent track to perform operations in accordance with the technological process.

For cutting the ballast and laying out the base, sets of earthmoving machines are used. When using sets of earth-moving machines recommended for lowering the marks of the longitudinal profile of the railway track, labor costs and time for performing work are determined in accordance with the technical standards given in standard technological processes.

In the absence of standard sets, the number of machines and their operating time are selected in accordance with the amount of work on cutting and laying out the ballast and the productivity of the machines (Tables 5 and 6). Branches are planned with a slope of 0.02.

Table 5 Volumes of earthworks performed when laying a pavement with a length of 100 m

Indicators	Covering depth, cm
Indicators
Branch length, m
Volumes of cutting, m 3:
on the main site
"recusal
Total
Planning area, m 2

On double-track sections, where the total load on both tracks does not exceed 55 pairs of trains per day, a track plow can be used to cut the ballast. The thickness of the ballast layer cut in one pass of the plow is approximately 5-8 cm. When using a plow, it is also necessary to use a bulldozer that will plan the shoulder.

In areas with splashes from weeds, the layer of rubble under the non-woven material is cleaned with a BMS machine. In this case, the planer of the machine must be installed in such a way that the base under the non-woven material is leveled evenly without rollers of cleaned crushed stone under the rails and without a groove in the middle of the track.

When placing strips of material along the axis of the track, the spreading is carried out starting from the roadside to the inter-track with the corresponding overlap of the strips.

Table 6 The time of employment of machines when performing earthworks on a 100m section

Types of jobs	Time consumption, machine-hours, at the depth of laying the coating, cm
Types of jobs
Ballast cutting:
bulldozer with a direct blade with a power of up to 59 kW
bulldozer with a direct blade with a power of up to 96 kW
bulldozer with a rotary blade with a power of up to 96 kW (in layers)	0,68	0,91	1,14	1,37	1,88
Base layout:
79 kW bulldozer					0,81	0,81
79 kW motor grader

The links of the rail-sleeper grid are placed directly on the non-woven material. It is not allowed to turn over the first links of the rail packages of the track-laying train on the surface.

The track is raised to the ballast without the use of strings in several passes of an electric ballast, a crushed stone cleaning machine or a VPO-3000 machine. The lifting height in one pass should be no more than 10 cm when using the SHOM and ELB machines and no more than 8 cm when using the VPO-3000 machine. The first lift is performed on the fine ballast (see). After each lifting of the track, the ballast is re-unloaded from the hopper-dispensers. With this technology, it is advisable to place the ballast between two groups of wagons with ballast.

The use of VPO-3000 and VPR machines is allowed after a layer of ballast with a thickness of at least 20 cm is located between the sole of the sleepers and the coating of non-woven material. If this layer is thinner, the use of these machines is prohibited, since their working bodies will damage the coating.

The first two trains pass at a speed of 25 km/h, and the next - 60 km/h.

13.6. Final works are carried out in accordance with standard technological processes for major and medium track repairs. During the final work, roadsides are planned, cut soil is removed, and drainage systems are arranged in accordance with the project.

INSTALLATION OF NON-WOVEN FABRIC AND WATERPROOFING FILM ON AN UNSTABLE EMBRACE

13.7. In the preparatory period, in accordance with the project, the strips of non-woven material and film are measured, cut and numbered in the desired sequence.

The length of a continuous strip of film should be equal to the unfolded width of the coating on the slopes and within the main area. Strips of nonwoven material are cut for two layers. At the same time, the full length of the strip can be assembled from three "(or two) separate parts: for slopes and the main platform. On the side, strips of non-woven material are welded into panels of such a size that they can be moved to the place of laying. Panels for slopes and the main platforms can be welded separately.

13.8. The main work is carried out in the "window" with the removal of the rail and sleeper grid. The old ballast is cut off to design marks by bulldozers, auto scrapers or a plow-snow plow from an adjacent track (on a double-track section). The panels of non-woven material, mounted for the main platform, are laid on the planned base. Film strips are laid across the path, overlapping them by at least 0.25 m. At the same time, the necessary part of the film strips is placed on the main platform, and the remaining parts intended for slopes are left rolled up on the sides.

A second layer of non-woven material is laid on top of the film. In parallel with these works, fencing drainages are arranged along the edges of the coating. A rail and sleeper grid is laid on the covering made within the main platform and the track is ballasted.

13.9. Pavement works within the slopes can be carried out without interruption in the movement of trains. At the same time, the necessary planning and cutting of the soil on the slopes are manually carried out. Sloping panels are welded on the side of the road with the lower panel on the main platform. Film strips with an overlap are rolled out from the wound rolls along the slope and the upper panels of the non-woven material are mounted on top of them by welding between them. Laying of coating materials on slopes is advisable from the top of the embankment.

The film and non-woven material are launched into the dug ditches of drainage systems. Under the film strips perpendicular to the ditches, a separate longitudinal strip of the film is brought, covered with non-woven material, crushed stone is poured on top and wrapped with this material.

The coating on the slopes and roadsides is covered with a layer of draining soil, bringing the slope to the design outlines.

STRENGTHENING FLOODED SLOPES

13.10. When performing construction and installation works to protect the slopes of structures with rock riprap and prefabricated concrete and reinforced concrete slabs, it is necessary to be guided by the current standards, building codes and these Technical Instructions.

13.11. Before laying the slabs, the soil is compacted at the base of the coating (on the slope) and control tests of its density are carried out, and thrust structures (tooth) are constructed at the base of the embankment. For the work performed, an appropriate executive documentation, including acts of hidden works.

13.12. The layout of slopes for laying non-woven material is carried out by mechanisms with manual finishing of the slope surface to the design marks. Deviation from the design surface of the slope is allowed no more than ± 5 cm at a length of 3.0 m.

The preparation of the base for laying the non-woven material and its laying on the slope are carried out in small sections, according to the amount of work performed during the day. IN winter conditions strips of non-woven material are rolled out immediately before laying the next batch of plates on a slope cleared of snow.

If, before laying the slabs, the planned slope is eroded by surface, rain or river water, then the slope surface is brought to the design marks by adding fine crushed stone, sand-gravel mixture or coarse sand with moisture, while removing and laying again the non-woven material in the areas of erosion that has occurred.

13.13. Strips of non-woven material are laid on the slope from top to bottom with a mutual overlap of 10 cm and connected with a continuous seam using blowtorch welding. The panels are fixed from displacement by weighting, pinning, pins, brackets or wooden stakes.

13.14. When arranging rock placement, the stone is poured with vibrating trays, a bucket transported by a crane, or an excavator bucket.

When leveling a stone on a non-woven material coating, it is necessary to monitor the integrity of the sheets and butt joints. Leveling of crushed stone preparation for laying non-monolithic slabs with flexible connections (see Fig. 13, b) are performed manually. If the non-woven material is damaged, the gaps are covered with pieces of this material, providing an overlap of at least 0.2 m. The pieces of material are welded to the main fabric.

Reinforced concrete slabs are laid on the cards from the bottom up, guided by the requirements of VSN 82-69 and the following instructions.

The slinging of the slabs must be carried out in such a way that the planes of the slabs, when they are lowered, are parallel to the slope surface.

For this purpose, traverses or slings of different (chosen locally) lengths are used.

When mounting adjacent plates, monolithic along the contour with the ZNIIS key, stop templates are used, the dimensions of which provide the required gap between the plates.

The displacement of the edges (ends) of the slabs along the line parallel to the edge of the slope should be less than 5 mm, but normal to it - less than 10 mm.

13.15. After laying on the slope, the slabs are welded into cards. Before welding, in the places of its production, the non-woven material in the seam is sprinkled with sand with a layer of 3-4 cm.

Immediately before monolithing, the seams and welded joints are thoroughly cleaned of sand and debris. The quality of welded joints and cleaning of seams is confirmed by the act.

13.16. The seams are monolithic with high-strength fine-grained concrete grades 400-500 with the largest aggregate size of 10-15 mm. Compaction of the concrete mixture should be carried out using standard mechanical vibratory compactors. Monolithic work should be carried out at stable positive temperatures.

APPENDIX.

Nonwoven Test Method

The general conditions for testing non-woven material must comply with "Textile non-woven fabrics. Rules for acceptance and sampling."

Linear dimensions and the mass of non-woven material is determined according to GOST 15902.1-80 "Non-woven fabrics. Methods for determining linear dimensions and mass".

Strength nonwoven material in uniaxial tension is set in accordance with "Nonwoven fabrics. Methods for determining strength".

The uniaxial stretch reflects the performance of a nonwoven fabric laid on a slope to improve stability. The safety factor of a nonwoven material under uniaxial tension, taking into account the joint work of this material with the soil due to friction and adhesion forces, is taken equal to n = 1,2.

The nonwoven material is tested for biaxial tension and water permeability on non-standard models.

biaxial stressed the state characterizes the work of non-woven material in the under-rail base: in the ballast prism, on the main platform of the subgrade, under the embankment. The tests are carried out on a model of a square membrane with a side dimension of 105 mm. The sample is fixed in the frame on all sides. A uniformly distributed load is applied to the surface of the membrane, the size of which increases until the destruction of the material. Stresses in the membrane in two mutually perpendicular directions (excluding anisotropy)

where E- modulus of elasticity of the material, kgf/cm 2 ; R- load on the membrane surface, kgf / cm 2, b, t- geometric dimensions of the membrane, see

Meaning σ xc= σ yc, obtained empirically for a particular type of material, is taken as the limit in the calculations.

Vertical water permeability TO The nonwoven material can be determined in serial devices for sandy and clayey soils (for example, the SPETSGEO tube, the Kamensky tube, the F-1M device), placing the material in them in several layers (in a stack). The method is applicable to both two-layer (non-woven material and primer) and single-layer (non-woven material) media.

Horizontal permeability(along the material layer) TO G is determined in a special device consisting of a metal cup with perforated walls. The height of the perforated part corresponds to the height of the layer (foot) of the material. A piston with a hole of a certain radius in the center is placed on top of the material.

Through this hole, water under pressure enters the material, its filtration is carried out only in the horizontal direction. Filtration coefficient along the material layer

where l n - piston length, m; R- outer radius of the piston (sample), cm; r- inner radius of the piston, cm; Q- water consumption, m 3 / s; H- sample height, m; ∆h- pressure in the sample, m

The piston can be loaded with a load corresponding to the actual operating conditions of the non-woven material layer in the structure.

current

Approved by the Ministry of Railways on May 3, 1988

The Technical Instructions set out the requirements for the design and calculation of anti-deformation structures made of non-woven material, laid to eliminate track subsidence, intense rail gauge disturbances, slope slides, as well as to prevent the formation of ballast troughs and beds on the main subgrade area and erosion. The main provisions on the organization and technology of work in the construction of these structures are given.

For engineering and technical workers of the track facilities.

Responsible for the issue P.I. Dydyshko, V.V. Sokolov

Head of editorial office V.G. Peshkov

Editor L.P. Topolnitskaya

Issued by order of the Ministry of Railways of the USSR

INTRODUCTION

Under the conditions of increased traffic density and loads from the rolling stock on the rails and an increase in the speed of trains, the intensity of track breakdowns increases, which adversely affects the carrying capacity of railways.

The stability of the railway track largely depends on the subgrade, which is composed of clayey soils for about 70% of its length. Under the combined influence of a moving load and climatic factors, the subgrade in these places is unevenly deformed. The main platform (the interface between ballast materials and clay soils) is often affected by ballast troughs and stocks. As a rule, the intensity of path disorders in terms of level and profile in these areas is increased. In some cases (approximately 1% of the total network length), track subsidence occurs, which is accompanied by uneven subsidence and shifts of the rail gauge, liquefaction of clay soil with splashes from under the sleepers, squeezing masses of this soil onto the surface of the ballast prism. They intensify with thawing of the soil and rainfall. Under favorable engineering and geological conditions, deformations of the under-rail foundation can manifest themselves in places of increased dynamic impact of a moving load (turnouts, leveling spans of a seamless track, etc.), as well as in heavily clogged areas.

In modern operating conditions, the possibility of providing "windows" in the movement of trains to perform work to strengthen the subgrade and the track as a whole with high traffic density is limited. This makes it necessary to reduce the volume of earthworks to the maximum extent and to switch to the use of artificial materials with the necessary properties in anti-deformation structures.

For thermal insulation, foam is used, which prevents seasonal freezing - thawing of clay soils, for hydraulic isolation- a polymer film that prevents infiltration of atmospheric precipitation. Thermal and waterproofing coatings are laid within the ballast prism. The requirements for their arrangement are set out in the Technical Instructions for Eliminating the Causes and Drawdowns of the Railway Track, TsP/4369.

Non-woven synthetic material, which is currently being increasingly used in the construction and operation of structures for various purposes in our country and abroad, is able to separate and reinforce soils, drain and divert water. This material is made from synthetic fibers (waste, recycled raw materials or primary from polymer melt), which are mechanically interconnected on needle-punching machines, where special needles entangle them in a layer. For the production of materials, fibers from various polymers (polyester, polyamide, polypropylene, etc.) are used, the chemical and biological resistance of which ensures their service life in the soil for several decades. The use of natural fibers is excluded, as they are short-lived when working in the ground.

The most important properties of nonwoven materials include the following:

the ability to retain small particles of soil (filter property);

high water permeability;

high mechanical tensile strength combined with elasticity and elongation;

manufacturability of application (low consumption per unit area, ease of transportation, installation and connection).

Possessing the specified set of properties, the nonwoven material performs one of its functions - the role separating layer. The stress-strain state of the soil, formed under the combined influence of loads and climatic factors, changes after laying the non-woven material. This layer prevents the manifestation of residual deformations of the soil, since the freedom of movement of individual particles is limited. They cannot pass through the material. This prevents the interpenetration of large particles into the clay soil and small particles into the draining soil. The shift of individual layers, aggregates or soil particles in the zone of the interlayer is difficult.

Reinforcing function material lies in the fact that it is able to withstand tensile forces and increase the bearing capacity of the soil base reinforced with this material. In this case, the stresses in the soil mass are redistributed. The interlayer, working as a membrane, transfers some of the stresses, leveling them to a certain extent, from more loaded places to less loaded ones.

Cast return filter the material prevents mechanical suffusion, i.e. removal of small soil particles by water flow. At the same time, in the direction of water movement in front of the layer of non-woven material, as a result of re-sorting of particles, an additional natural soil return filter is formed.

Work of nonwoven fabric as drainage layer(drainage function) is possible due to its high water permeability along the web. For example, when a material is located on a soil with a low filtration coefficient, the flow of infiltrating sediments, having reached a layer of this material, will begin to move along it. Some of the water will go down into the ground, but some of it will change its movement in the direction of less resistance and be diverted away from the ground in need of protection.

These functions are manifested, depending on the type of deformities to be eliminated, separately or, which occurs most often, together.

Non-woven material is used to eliminate and prevent subsidence of the track, intense disorders of the rail gauge, slope slopes of embankments and excavations, erosion of flooded slopes, uneven settlement of embankments in swamps, siltation of drainages for various purposes, etc. In some cases, this material is used in combination with a waterproofing film.

Part of the deformations practically or cannot be eliminated without the use of non-woven materials, or their elimination requires significant labor and material costs, as well as long breaks in the movement of trains. Such deformations include subsidence of the track with extrusion of liquefied soil onto the surface of the ballast prism, slope slips during surface waterlogging, soil washing out from under the slabs of the bank protection structures and flooded embankments, etc. Nonwoven material is indispensable in those structures where, when using draining soil, work with high, often difficult to achieve accuracy (installation of a return filter in drainage and other structures).

The use of non-woven material coatings instead of traditional designs reduces the cost of eliminating and preventing deformations. At the same time, labor costs for the maintenance of the subgrade and the track as a whole, its overhaul or construction are reduced, the throughput of the lines is increased, and significant cash savings are achieved.

These Technical Instructions contain the main provisions for obtaining initial data for design, the conditions for the use of nonwoven materials, the necessary requirements and recommendations for the installation of anti-deformation structures made of these materials, as well as the organization and technology of work.

The guidelines have been developed on the basis of the results of experimental and pilot-production use of non-woven material on railways, analysis of foreign experience, laboratory tests and calculations.

The technical guidelines were developed by VNIIZhT, KhabiIIZhT, HIIT, VNII Transport Construction together with the Main Department of Railways of the Ministry of Railways and the Northern Railway.

1. GENERAL PROVISIONS

1.3. Strengthening the subgrade with the use of non-woven materials in areas with subsidence of the track, slope slopes of embankments and cuts, water washouts and other types of deformations in difficult engineering and geological conditions is carried out according to projects developed on the basis of the terms of reference of the track service, which indicates a list of deformable sections according to the data operational observations and technical passport of the track distance.

Work to eliminate intense disorders of the rail gauge in terms of level and profile using non-woven material is envisaged in projects for major and medium track repairs. The repair estimate documentation includes the specified works. The feasibility of application and specific areas for laying non-woven material are established on the basis of operational data on the state of the track, labor costs for its maintenance, rail outlet, wear of elements of the upper structure and other indicators.

Together with the laying of non-woven material, the projects provide for the reconstruction or construction of new drainage systems to ensure the runoff of infiltrating precipitation from the coating of non-woven material.

2. INITIAL DATA FOR DESIGN

2.2. During an engineering-geological survey to develop a project to eliminate deformations of the under-rail foundation (track subsidence, intense rail gauge disturbances in level and profile on an unstable subgrade, uneven heaving of homogeneous soils), an inspection of the site is performed, characteristic signs of deformations are recorded and instrumental survey is carried out. By drilling, digging or pits with sampling, the composition, composition and condition of the subgrade soils are determined. At the same time, at least five points of the under-rail foundation (along the axis of the track, under both rails from their outer side and at a distance of 20-40 cm from the ends of the sleepers) in the sleeper box and under the sleeper, the configuration of the clay soil surface on the main platform of the subgrade is established. The presence and depth of groundwater, sources of local soil moisture and other hydrogeological conditions are determined. The required volumes and procedure for conducting an engineering-geological survey are established in accordance with the requirements of the Technical Instructions for the Elimination of Deeps and Drawdowns of the Railway Track, TsP / 4369.

2.3. The initial data for the design and calculation of coatings using non-woven material in order to eliminate deformations of the embankment slopes are obtained in the required volumes in accordance with the requirements of the Temporary Guidelines for Calculating the Stability of Exploited Embankments and Designing Counter-Banquets (M.: Transport, 1979. 32 s).

When examining embankments with sliding slopes, it is expedient to delineate the interface between the draining soils of the ballast layer and the plume and the clay soils of the embankment along its entire cross section to carry out exploration cross-cuts. Slots are laid in the area of deformations and beyond.

2.4. During the engineering-geological survey of the deforming slopes of the excavations, a geodetic survey of transverse profiles is performed, the nature of soil stratification in the slope parts, hydrogeological conditions, sizes and nature of deformations, as well as the depth of the soil softening zone under the influence of natural weathering processes are determined, the composition, condition and properties of soils of each varieties. Soil strength indicators are set in accordance with the requirements of the regulatory and technical document specified in clause 2.3.

2.5. The fastening of flooded slopes is designed on the basis of the initial data obtained in accordance with the requirements of the Manual on surveys and design of railway and road bridge crossings over watercourses (TsNIIS, Glavtransproekt. M .: Transport, 1972. 272 p.).

3. CONDITIONS FOR APPLICATION OF NON-WOVEN MATERIALS TO REINFORCEMENT THE GROUND PLATE

3.1. Non-woven material is used to eliminate deformations on operated lines.

Conditions for the use of non-woven material, depending on the type and causes of the formation of deformations during various types subgrade are given in table.1.

3.2. To reinforce the subgrade, non-woven material is used, which must meet the following requirements:


Strip width, mm
Thickness, mm
Weight 1 m, g
Breaking load, kgf, for a strip 5 cm wide in the direction:
longitudinal
transverse
Elongation at break, %, in direction:
longitudinal
transverse
Water permeability (filtration coefficient), m/day

3.3. In the anti-deformation structures of the railway subgrade, it is possible to use a non-woven material that meets the above requirements, manufactured according to the specifications "Needle-punched fabric for road construction - dornit. Specifications" TU 21-29-81-81 *, type 1, which is intended for roads with increased bearing capacity . The use of type 2 and 3 material to reinforce the railway subgrade is not permitted.
________________
* Specifications mentioned hereinafter are not given. See the link for more information. - Database manufacturer's note.

In addition, it is allowed to use non-woven materials produced according to other specifications, including imported ones, if they meet the above requirements, as well as non-woven fabrics used at chemical fiber factories for filtering viscose solutions, washed and sewn into strips.

Test methods for non-woven material are set out in the specified TU 21-29-81-81.

Table 1. Conditions for the use of non-woven materials in anti-deformation structures


Type of deformation	Type and elements of subgrade	Reasons for the formation of deformations	Anti-deformation measures
A. Elimination of deformations on operated lines
Landing paths with extrusion of liquefied clay soil through the ballast layer during thawing and heavy rains; rail gauge disturbances in level and in the profile with the formation of splashes due to the penetration of clay particles into the ballast layer from the main platform		Insufficient bearing capacity of clay soils as a result of increased moistening by infiltrating moisture in the presence of ballast troughs and beds on the main site	Laying a non-woven material covering the entire width of the subgrade on top; with a depth of ballast beds of more than 0.5 m - laying a coating of non-woven material in combination with a waterproofing film; arrangement of closed drains, deepening of cuvettes and trays below the bottom of ballast beds
Disorders of the rail gauge in terms of level and in the profile with the formation of splashes as a result of clogging mainly in the area of junctions, leveling spans, turnouts, crossings	Cuts, zero places and embankments, composed of clayey, draining and rocky soils, tunnels and bridges with ballast ride	Insufficient bearing capacity of the polluted ballast layer when moistened by precipitation	Laying non-woven material covering within the ballast prism under the rail-sleeper grid
Uneven heaving of subgrade composed of homogeneous clay soils	Notches and zero places in clay soils, embankments from clay soils	High uneven wetting of heaving soils with infiltrating moisture at different depths of ballast troughs and beds on the main site	Laying non-woven material in combination with a waterproofing film over the entire width of the subgrade on top
Slopes and track settling on unstable embankments	Mounds of clay soils on a solid foundation	Increased moistening of the upper layers of the soil within the main area and slopes with infiltrating moisture, stagnation and accumulation of moisture in ballast depressions on the main area, in cracks and depressions on the slopes	Laying within the main site and slopes of non-woven material covering on potentially unstable areas of embankments, including in combination with the arrangement of counter-banquets; laying a combined coating of non-woven material and a waterproofing film on embankments with active manifestation of deformations
Washouts, slips and slides of slopes of excavations	Excavations in homogeneous clay, as well as in heterogeneous (clay, draining) soils	Increased soil moisture during thawing and due to infiltrating precipitation, access to the surface of groundwater	Laying a coating of non-woven material on the slope of the excavation with its anchoring at the top in the sloping part
Destruction of the reinforcement of flooded slopes, erosion of slopes	Embankments, dams, counter-banquets	Carrying out of soil under the influence of high flow rates, waves, rise and fall of levels
Erosion of the banks and bottom of the channels of watercourses near artificial structures, as well as erosion of the slopes of embankments or cones	Embankments at the junctions with artificial structures, at the shores of rivers	Water washout	Laying non-woven material with riprap instead of fascines, mattresses, etc.
Uneven settlement of embankments in swamps	Mounds in the swamps	Insufficient bearing capacity of the foundation of the embankment	The device of berms with laying under them of non-woven material
Silting of drainages for various purposes	Drainage systems in excavations, zero places and embankments	Mechanical suffusion of soil	Application of non-woven fabric as return filter
B. Deformation prevention
Possible subsidence of the track with the formation of ballast troughs and beds on the main site, extrusion of liquefied clay soil through the ballast layer	Notches and zero places in clay soils, embankments from clay soils	Insufficient bearing capacity of clay soils with a typical ballast prism without a protective layer	Laying non-woven material together with a drainage pad on the main subgrade area
Possible destruction of the reinforcement of flooded slopes	Embankments, dams, counter-banquets	Removal and suffusion of soil	Laying a non-woven material under the outer reinforcement as a return filter

3.4. Parameters for the definition of which there are no regulatory documents are set on non-standard models that take into account the mode of operation of non-woven material in railway track structures. These parameters are determined in accordance with the test procedure set out in the annex.

3.5. When installing a combined coating (see Table 1), together with a non-woven material, a waterproof film is used, for example, a PVC film of brand B with a thickness of 0.23 mm (GOST 16272-79).

The film used must have the following characteristics:


Width, mm
Thickness, mm
Tensile stress, kgf/cm
Elongation at break, %
Vapor permeability for 24 hours, g/m
Brittleness temperature, °С

4. ELIMINATION OF DOWNLOADS OF THE WAY AND DISORDERS OF THE RAIL TRACK ON UNSTABLE SECTIONS OF THE GROUND PATH

4.1. To eliminate subsidence of the track and disorders of the rail gauge in terms of level and profile, on unstable sections of the subgrade with a depth of ballast troughs and beds of less than 0.5 m, a coating of non-woven material is laid. The design of this coating in cross section on single-track and double-track sections of railways is shown in Figures 1 and 2.

Fig.1. Schemes for laying a coating of non-woven material when eliminating subsidence of the track and disorders of the rail gauge in terms of level and profile on unstable sections of the subgrade within the embankments

Fig.1. Schemes for laying a coating of non-woven material when eliminating subsidence of the track and disorders of the rail gauge in terms of level and profile on unstable sections of the subgrade within the embankments:

but- on a single-track line; b, c 1 - non-woven material; 2 - ballast; 3 - clay soils

Fig.2. Schemes for laying a coating of non-woven material when eliminating subsidence of the track and disorders of the rail gauge in terms of level and profile on unstable sections of the subgrade in the recesses

Fig.2. Schemes for laying a coating of non-woven material when eliminating subsidence of the track and disorders of the rail gauge in terms of level and profile on unstable sections of the subgrade in the recesses:

but- on a single-track line; b, c- on a double-track line for one track and two tracks; 1 - non-woven material; 2 - ballast; 3 - clay soils; 4 - drainage; 5 - tray

Non-woven material is placed at a depth of at least 0.2 m below the sole of the sleepers () on the surface of ballast materials cut and planned with a slope of at least 0.04 to the field side.

If the distance from the top of the ballast prism to the main area of the subgrade of sandy loam and loam with a yield boundary is less than 0.7 m along the axis of the path, and less than 1 m for heavier loam and clay, then after laying the coating of non-woven material, an additional lift is performed ways to achieve the specified values.

The coating is laid across the entire width of the subgrade on top. On double-track sections, in the absence of deformations on the adjacent track, it is possible to cover only one track.

The bottom of ditches, flumes, closed drains in recesses and at zero places should be located 0.2 m below the cover and 0.15 m below the bottom of the ballast beds. If these conditions are not met, the drainage systems are rebuilt, lowering their bottom level.

The pavement to eliminate subsidence of the track and disorders of the rail gauge under the turnouts must be of variable width. The edges of the coating are located behind the ends of the transfer bars by at least 0.9 m (Fig. 3, but). It is laid 0.2 m below the sole of the bars with a slope of at least 0.02.

Fig. 3. Scheme of the non-woven material coating device when eliminating subsidence of the track

Fig. 3. Scheme of the coating device from non-woven material when eliminating subsidence of the track:

but- on turnouts; b- on station tracks; 1 - non-woven material; 2 - drainage; 3 - ballast; 4 - clay soils

When laying the pavement under the turnouts and on the station tracks, a shallow drainage is laid along the inter-track with a longitudinal slope of at least 0.03, the release of which is carried out by transverse drainage (see Fig. 3, a, b). To do this, use pipe filters or a "deaf" drain with a diameter of at least 15 cm, which is made of crushed stone wrapped in non-woven material. The bottom of the drain must be below the edge of the cover.

In a similar way, if necessary, water is drained from the inter-track on the hauls in curved sections of the track.

When crushed stone of ordinary size is used in the ballast layer, a layer of sand, asbestos ballast or fine crushed stone of a fraction of 10-25 mm with a thickness of 5-10 cm is laid on the non-woven material.

Separate strips of non-woven material in the coating are placed across the track when eliminating subsidence of the track, i.e. the length of these strips should be equal to the width of the coating. The strips must overlap each other by at least 0.2 m. When eliminating rail track disorders in terms of level and profile on unstable sections of the subgrade, it is allowed to place strips of non-woven material along the track with a mutual overlap of at least 0.2 m.

In difficult engineering-geological conditions, with intense manifestation of subsidence of the track with extrusion of liquefied soil through the ballast, the non-woven material in the coating can be laid in two layers. In this case, crushed stone of normal size can be directly laid on the non-woven material.

The section covered with non-woven material must overlap in length the section of the track with manifested deformations by at least 30 m on each side. The minimum length of the coated section can be 30 m.

It is not allowed to lay a coating of non-woven material to eliminate subsidence of the track and disorders of the rail gauge in terms of level and profile on unstable sections of the subgrade only within the rail joints.

4.2. To eliminate the track deformations considered in this paragraph in areas where the depth of ballast troughs and beds on the main subgrade area is more than 0.5 m, a combined coating of non-woven material and a waterproofing film should be used. The film is placed between two layers of non-woven material (Fig. 4).

Fig.4. Scheme of a device for a combined coating of non-woven material and a waterproofing film when eliminating subsidence of the track

Fig.4. Scheme of a device for a combined coating of non-woven material and a waterproofing film when eliminating subsidence of the track:

1 - non-woven material; 2 - waterproofing film; 3 - new ballast; 4 - uncut ballast; 5 - clay soil

The coating is placed at a depth of at least 0.3 m from the bottom of the sleepers or transfer beams (when laying under turnouts).

Crushed stone of normal size can be laid directly on the combined coating.

Strips of non-woven material and waterproofing film are spread along the path, starting from the bottom side, which allows water to drain from the coating in the transverse direction.

The remaining requirements for the coating device are observed in accordance with clause 4.1.

5. ELIMINATION OF RAIL TRACK DISORDERS IN THE LEVEL AND IN THE PROFILE WITH THE FORMATION OF SPLASHES IN COLLECTED AREAS

5.1. The non-woven material is placed within the ballast prism at a depth of at least 20 cm from the base of the sleepers (Fig. 5, but).

Fig.5. Schemes for the construction of a non-woven material coating when eliminating rail track disorders in terms of level and profile in areas with splashes from clogging

Fig.5. Schemes for the construction of a non-woven material coating when eliminating rail track disorders in terms of level and profile in areas with splashes from clogging:

but- on hauls; b- within turnouts; 1 - ballast layer cleaned; 2 - non-woven material; 3 - the ballast layer is polluted; 4 -drainage

Under a layer of non-woven material, crushed stone must be cleaned of weeds to a depth of at least 10 cm in order to ensure the most complete and rapid removal of infiltrating moisture into this layer. Laying non-woven material on unplanned rollers of cleaned crushed stone in under-rail sections, remaining after the operation of the ballast-cleaning machine, is not allowed. This surface must be level.

When crushed stone of ordinary size is used in the ballast layer, a layer of fine crushed stone or sand 5-10 cm thick is poured onto the non-woven material. This layer can be omitted if the non-woven material in the coating is laid in two layers: the placement of the second layer is allowed within the width at least 0.8 m below each of them (for example, by appropriately overlapping two lanes in these places).

5.2. The operation of straightening and tamping machines during the laying of the coating until a 20 cm thick layer of ballast is created under the sole of the sleepers is not allowed, since in this case the coating will be broken (VPR) or assembled under the rail-sleeper grid (VPO).

5.3. The accumulation of weeds above the nonwoven interlayer will occur in the usual way, however, the drainage conditions in this case are more favorable, since the moisture filtration path and time will be reduced compared to a conventional ballast prism design without nonwoven material. Rapid drainage of water down and to the side will protect weeds from waterlogging, which increases the bearing capacity of the ballast layer.

The non-woven material is laid under the rail-sleeper grid to a width of at least 4.5 m. Within the limits of the turnouts, the width of this coating must be variable and exceed the length of the transfer bars by a value of m on each side (Fig. 5, b).

In areas with a stable subgrade, in which rail track disorders in level and profile with the formation of splashes occur due to weeds, a continuous coating is arranged; at the same time, in some justified cases, it is allowed to cover only under the joints, and in sections of the continuous track - under the leveling spans. On turnouts, it is allowed to lay the material in the areas of the cross and the frame rail, which are most subject to dynamic action from a moving load. The edges of the coating must be separated from the joints by at least 2 m.

To drain water in the transverse direction, a layer of non-woven material is brought on hauls to the slope of the ballast prism, and on station tracks and turnouts - to shallow drainage. This drainage is arranged in accordance with the requirements of clause 4.1.

5.4. The pavement within the abutments of bridges, as well as the spans of reinforced concrete bridges with a ride on ballast, is laid at the depth indicated above, bringing to the sides of the ballast troughs (back walls of the abutments). Longitudinal water drainage is carried out using drains, which are placed along these sides. Drains in this case can be made of non-woven material, which is rolled up from a strip about 1 m wide.

6. APPLICATION OF COATING FROM NON-WOVEN MATERIAL AND WATERPROOFING FILM FOR ELIMINATION OF DEPOSIT

6.1. The conditions for the use of this coating are set out in Table 1. Uneven heaving with homogeneous soils manifests itself in this case as a result of ongoing (or ongoing) subsidence of the track. The ballast troughs and beds of various depths that have arisen during these subsidences lead to increased uneven moistening of cohesive soils that are infiltrated with moisture. Due to its properties, non-woven material cannot be used independently to eliminate abysses. It is used for this purpose in conjunction with a waterproofing film that traps infiltrating precipitation.

6.2. The design of the coating of non-woven material and waterproofing film to eliminate heaves under the conditions under consideration is performed in accordance with the requirements set forth in clause 4.2.

7. ELIMINATION OF SLIDES AND TRACK SETTLEMENTS ON UNSTABLE EMBRACES ON A SOLID FOUNDATION

7.2. A non-woven material cover can be used if embankment slopes do not occur, but the following signs of deformation appear:

precipitation, including one-sided, and shifts of the rail gauge, usually associated with the period of thawing of the soil and intense rains;

cracks at the ends of the sleepers, on roadsides and slopes;

settlements of roadsides, uplift of soil on slopes;

change in the steepness and shape of the slopes.

The use of such a coating is most appropriate to increase the stability of the embankment in its upper part, which has a height (counting from the top) of 6-8 m, with a thickness of a potentially unstable soil mass on the slope up to 1.5-2 m. In this part of the embankment, as a rule, , unstable ballast loops and it is usually not possible to ensure its stability by backfilling counter-banquets.

7.3. The coating consists of a non-woven material laid on the surface of the slope, and a layer of draining soil poured on top. The non-woven material is anchored in the upper part outside the potentially unstable array, placed in a ballast prism under the rail-sleeper grid. Under these conditions, the joint work of the nonwoven material and the soil is ensured due to the forces of friction and adhesion between them. Shear forces, which are an integral part of gravity, in the presence of a coating, must overcome not only the holding forces that develop on the surface of possible displacement (friction and adhesion forces), but also the resistance of the interlayer to rupture. The pavement parameters that ensure the stability of the embankment with a given coefficient are determined by calculation. In this case, three conditions must be met simultaneously: sufficiency of adhesion of the non-woven material with the underlying soil; tensile strength of the material; reliability of anchoring in the upper part.
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Non-woven synthetic material (NSM) is a needle-punched non-woven fabric, which is made by interlacing synthetic polymer fibers. It is not subject to wear and tear. Due to the combination of excellent performance, the material is convenient to use in most areas of human life: construction works, road construction, pipeline laying, agriculture, design and more.

NSM is capable of performing four functions at once:

Filtration. Due to the unique structure, the canvas prevents the passage of sand and earth particles into the pores of the material, preventing the possibility of silting;
Drainage. Prompt water drainage is provided, which increases the efficiency of the drainage system;
Reinforcing. Like a geogrid, it takes on the ground load and can partly withstand tensile stress;
Dividing. NSM serves as a separating layer, excluding mixing of the upper layer and the base. At the same time, the thickness of the top layer does not change.

Material advantages

NSM is widely popular today due to:

Durability;
Environmental friendliness. The canvas is not exposed to chemical elements, so that harm to people and nature can be avoided;
Strength. The material has high level resistance to mechanical stress, puncture. Stretch threads allow the web to be extended, which eliminates the possibility of damage during installation;
impact resistance natural factors. Does not cause debate, silting and does not rot. Resistant to UV rays, acids, alkalis and organic matter. The material is not affected by fungi and bacteria;
Ease of installation. HCM is supplied in easy-to-transport rolls, which can be cut into two parts with an ordinary hand saw if required. Also, the material can be cut with scissors and a knife;
Profitability. With all its advantages, NSM is relatively inexpensive, which is the main reason for its use in many areas of life.

Areas of use

It is a filter in drainage systems;
Road works. It is used for laying the railway track, highway. It is assigned a reinforcing function; can also be used for garden paths.
Agriculture. NSM material can protect crops from weeds, and the soil from infection by microorganisms and drying out.
In construction. It is used as a waterproofing layer and a protective layer in the roof and foundation;
Strengthening the banks and slopes of reservoirs;

Table of NSM characteristics

The map is intended for the rational organization of labor of workers engaged in the construction of a layer of synthetic non-woven material (dornite) at the base of the subgrade (on a gripping length of 50 - 100 m) with rolling of the material in the longitudinal direction.

Designation:	KTP 6.03.1.2002
Russian name:	Arrangement of a layer of synthetic non-woven material (dornite) at the base of the subgrade with rolling of the material in the longitudinal direction
Status:	no expiration date
Replaces:	CT 10.5.1.90
Text update date:	05.05.2017
Date added to database:	01.09.2013
Date of entry into force:	01.01.2002
Approved:	01/01/2002 Rosavtodor (Rosavtodor)
Published:	SE Centrorgtrud of Rosavtodor (2002)
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MINISTRY OF TRANSPORT OF THE RUSSIAN FEDERATION

STATE ROAD SERVICE
(ROSAVTODOR)

CENTRE
ORGANIZATION OF LABOR AND ECONOMIC
MANAGEMENT METHODS
(TSENTRORGTRUD)

COLLECTION OF CARDS
LABOR PROCESSES FOR CONSTRUCTION,
REPAIR AND MAINTENANCE OF ROADS

Work process map

layer device
made of synthetic non-woven material (dornite)
at the base of the subgrade
with material rolling in the longitudinal direction

KTP-6.03.1-2002

Second edition, revised and enlarged

(Issue 6)

Moscow 2002

Cards labor processes designed to improve the organization of labor of workers employed in the construction, repair and maintenance highways.

Maps define progressive work technology, rational use working time, technological sequence of work performance based on advanced techniques and methods of work.

Maps can be used in the development of organizational and technological documentation for the construction, repair and maintenance of roads (PPR and others), work planning, as well as for educational purposes in the preparation of highly qualified workers.

A collection of maps of labor processes was prepared by engineers A.I. Anashko, E.V. Kuptsova, T.V. Insurance.

Responsible for the release of A.A. Morozov.

. Scope and effectiveness of the map

The name of indicators

unit of measurement

The value of indicators

for TE, EniR

Production for 1 person-day

Labor costs per device 100 m 2 layers of synthetic non-woven material (dornite)

Note: Labor costs include time for preparatory and final work - 2% and rest - 13%.

The use of the card will increase labor productivity up to 5 - 6%.

2. Preparation and conditions for the process

Name

Bulldozer on tractor T-130

Roller DU-29 (D-624)

Folding knife

Shovel shovel

Mounting brackets

Standard guards and safety signs

M 1 - brings the unit into working position, performs leveling and laying it in accordance with the design profile. At idling carries out partial compaction of the embankment.

Soil compaction of the base of the embankment in 6 passes in one track

M 2 - brings the unit into working position and compacts with 6 passes of the roller with a turn on the embankment.

Preparing rolls of dornite for rolling

D 1, D 2, D 3 - bring a roll of dornite to the place of rolling. At the ends of the grip, where the mandrel is rolled out, beacon poles are set up.

Unrolling rolls in the longitudinal direction, cutting webs, stapling

D 1 , D 2 - rolls are rolled manually over the entire width of the base. D 3 - after rolling out the first meters, the edge part of the web is fixed with 3 brackets, and during further rolling - after 1.5 - 2 m. D 2), continuing rolling in the opposite direction with an overlap with an overlap of at least 15 cm.

Quality control of work performed, correction of defects

D 1, D 2, D 3 - after rolling out the entire mandrel, by visual inspection, the quality of the laid layer, the quality of the joining of the sheets are checked. Transition to the next grip.

Group II soil development with a displacement of 20 m for backfilling dornite

M 1 - brings the unit into working position and develops, moves and unloads the soil onto the underlying layer of dornite with a return to the face empty.

Leveling the ground with a bulldozer

Soil compaction in 6 roller passes in one track