RU2679583C1 - Production method of a pipe with cable conduit and a continuous concrete coating and a pipe with a cable conduit (options) - Google Patents

Abstract

FIELD: pipeline equipment.

SUBSTANCE: method includes applying a concrete coating to a pipe with cable conduits attached to it, in which the concrete coating is applied to complete covering of cable conduits in its thickness. On the surface of concrete coating is applied artificially created stress concentrators in the form of annular grooves with a pitch sufficient to compensate internal stresses. Pipe with a cable conduit with a concrete coating includes at least one cable conduit installed on it and a concrete coating with applied stress concentrators in form of annular grooves. In another variation, a pipe with a cable conduit with a concrete coating includes cable conduits installed on both sides of it relative to the seam of cable conduit pipe and a concrete coating with applied stress concentrators in the form of annular grooves. Pipe is made longitudinal and the number of cable conduits on one side of the seam is not less than the number of cable conduits on the second side of the seam.

EFFECT: longer service life.

13 cl, 12 dwg

Description

The invention relates to pipeline technology, to pipes with a concrete coating, used when laying pipelines on offshore shelves, waterways, in flooded or wetlands, as well as in underground or above-ground pipelines in seasonally frozen and slightly bearing soils.

A known method of deploying one or more cable channels for fiber optic waveguides in a pipeline with a protective coating (see patent GB 2443832). In this invention, the cable channels are placed in a protective coating (layer) of the conductive pipe during coating formation (pouring or injection, followed by drying or polymerization). Or by drilling a protective coating (layer) with the subsequent introduction into the hole of the cable channel.

This method does not address the issue of compensation of internal stresses in the pipeline arising in the pipelines during operation, installation, as well as from the effects of natural and man-made factors.

The closest technical solution to the alleged invention is a method of manufacturing a concrete pipe with a cable channel (see patent RU 2616681, publ. 04/18/2017). In this method, a steel pipe with a corrosion-resistant coating is installed on the assembly stand, a reinforcing cage is mounted on its surface, the cage is fixed on the pipe, a cable channel is placed and fixed along the reinforcing cage. A protective shell is put on the structure, which is centered relative to the steel pipe, end plugs are installed, and concrete mixture is pumped into the resulting space.

The disadvantage of this method of manufacturing a concrete pipe with a cable channel should be attributed to the fact that it does not address the issue of compensating internal stresses in a pipeline using artificially created stress concentrators that arise in pipelines during operation, installation, as well as from the effects of natural and technogenic factors .

The technical result of the proposed technical solution is to increase the service life of concrete pipes by compensating for internal stresses arising in the pipelines during operation, installation, as well as from the effects of natural and man-made factors.

When laying a concrete pipe along the bottom of a reservoir or in wetlands in a conductive pipe and concrete coating, significant internal stresses arise due to elastic bending. In this case, partial uncontrolled delamination (chipping) of the concrete coating may occur. This detachment (cleavage) falling or receiving a moment of force having a reactive character (shooting), represents a certain danger for people performing installation work. In addition, delamination of the concrete coating at the passage of the cable channel can lead to crushing or deformation. This can be avoided by the use of artificially created stress concentrators in the form of annular grooves deposited on the outer surface of the concrete coating. Here, in the event of internal stresses in the concrete coating, they are absorbed due to the controlled formation of cracks in artificially created stress concentrators.

Internal stress in the concrete coating occurs in cases of bending of the concrete pipe (including the shift of the surface layer of the earth under the pipe in seasonally frozen, weakly bearing, and subject to technogenic factors soils).

The technical result is achieved in that in a method of manufacturing a pipe with a cable channel and a continuous concrete coating, comprising installing and fixing at least one cable channel on the pipe, applying a concrete coating to the pipe, in which the concrete coating is applied until the cable channels are completely covered in its thickness, and on the surface of the concrete coating, artificially created stress concentrators are applied in the form of annular grooves with a step sufficient to compensate for the internal stresses arising in the concrete.

In addition, specific operations for implementing the method are proposed, which are as follows:

- a concrete coating is applied above the cable channels by the amount of required operational safety.

- the concrete coating is applied by shotcreting.

- the concrete coating is applied by winding.

- the concrete coating is applied by injection under pressure.

- on the pipe, the reinforcing cage is fixed, and cable channels are placed under it or cable channels are placed on the reinforcing cage.

- the concrete coating is applied until the reinforcing cage is completely covered in its thickness.

A known method of increasing the resistance of sheet structural elements to the avalanche propagation of cracks (see patent RU 1281808, publ. 01/07/1987). In the present invention, grooves are applied to the conductive pipe of the pipeline by rolling by a roller. Grooves are stress concentrators that suppress the avalanche-like propagation of cracks. So, the crack originating in the conducting pipe, reaching the groove, is deflected and looped.

This method does not consider the use of stress concentrators in concrete pipelines, however, the positive effect of artificially applied voltage concentrators is seen here.

A known method and device for protecting hazardous sections of trunk pipelines from overvoltage (see patent RU 2143631, publ. 12/27/1999), in which they insert into a dangerous section of the pipeline of a safety coil made of a pipe with a diameter equal to the diameter of the main pipeline with welded control joint in the middle. The thickness of the safety coil is less than the thickness of the main pipeline in the range from 30 to 60% of the thickness of the main pipeline.

The safety system includes two valves with an automatic emergency closing system, a safety coil with a welded joint, voltage monitoring sensors on the latter, and sensors for transmitting the failure signal of the test joint to the automatic emergency closing system.

The disadvantages of this method include the fact that a rupture can occur anywhere in the safety coil, the monitoring sensor must be highly sensitive or several sensors must be installed.

In addition, this method is not applicable in the installation of concrete pipes, and considers the option of its implementation only under operational load.

The closest technical solution to the alleged invention is a method of protecting hazardous sections of trunk pipelines from overvoltage and a device for its implementation (see patent RU 2247891 publ. 03/10/2005), containing a conductive pipeline, a compensator, a safety system consisting of two automatic emergency valves closures, sensors and a safety coil equipped with an artificially created stress concentrator in the form of an annular groove, while the depth of the groove is determined by chnostyu tube at a working pressure.

In this patent, with a sharp increase in stresses on the main oil pipeline, the annular groove ruptures on the safety coil, which is detected by the sensors. As a result, automatic emergency shutdown systems are triggered and valves shut off the pipeline.

The disadvantages of this technical solution include the fact that it involves the protection of hazardous sections of trunk pipelines from stress during the period of operation (operation) and does not consider the option of protecting concrete pipelines during installation in the field.

In addition, this technical solution does not address the issue of positioning cable channels relative to the longitudinal weld of a longitudinal seam welded pipe.

When longitudinally welded pipes are used in oil or gas pipelines as a conductive pipe at the junction of two pipes, the standard distance between the longitudinal welds must be maintained. In the case of pipelines with pre-installed (embedded in concrete) cable channels, as a rule, the latter are not positioned relative to the longitudinal weld of longitudinally welded electric-welded pipes. Therefore, the installation of such pipes leads to significant losses (excessive length at the junction of the pipelines) of the cables for communication and monitoring systems laid in the cable channels, since the angular displacement of the cable channel relative to the longitudinal seams of the conducting pipes can be significant.

The technical result is achieved in that the pipe with a cable channel with a concrete coating includes a pipe with at least one cable channel installed on it and a concrete coating with applied stress concentrators in the form of ring grooves. According to the invention, the annular grooves are made on the outer surface of the concrete coating of the pipe with a step sufficient to compensate for the emerging internal stresses.

Also, the technical result is achieved in that the pipe with a cable channel with a concrete coating includes a pipe with a cable channel installed on it and a concrete coating with applied stress concentrators in the form of ring grooves. According to the invention, the pipe is made longitudinally, and provided with at least one more cable channel. Cable channels are installed on both sides relative to the seam of the pipe. The number of cable channels on one side of the seam is not less than the number of cable channels on the second side of the seam, grooves are made on the outer surface of the concrete coating of the pipe with a step sufficient to compensate for the emerging internal stresses.

Preferably, the concrete coating is made of a concrete mixture with nano-modified additives.

Preferably, the pipe is provided with a reinforcing cage.

Preferably, the cable channels are installed under the reinforcing cage or directly on the reinforcing cage.

The invention is further illustrated by examples of specific performance and the accompanying drawings, in which:

In FIG. 1 shows a section through a concrete-coated pipe and cable channels.

In FIG. 2 shows place I in FIG. one.

In FIG. 3 shows helically applied grooves on a concrete coating.

In FIG. 4 - shows the application of a concrete coating, for example, by gunning, until the cable channels are completely covered in its thickness.

In FIG. 5 shows the application of a concrete coating, for example, by gunning, above the cable channels by the amount of required operational safety.

In FIG. 6 shows the application of a concrete coating, for example, by gunning, until the reinforcing cage is completely covered in its thickness.

In FIG. 7 shows the application of a concrete coating, for example, by gunning, above the reinforcing cage by the amount of required operational safety.

In FIG. 8 - shows the positioning of the cable channels relative to the longitudinal weld of the conductive pipe /

In FIG. 9 - shows the binding (location) of abutting conductive pipes relative to their longitudinal seams.

In FIG. 10 - shows the bend of the concrete pipe at the time of installation.

In FIG. 11 - shows a crack in the groove of the protective coating of the pipe, formed from internal stress during bending.

In FIG. 12 shows the formation of a groove in the pressure injection method.

The claimed device consists of a pipe 1 with anticorrosive 2 and concrete 3 coating. On the pipe 1, a reinforcing frame 4 is fixed with cable channels 5 located under it.

The claimed method can be carried out as follows, a concrete 3 coating is applied to the cable channels 5 fixed to the pipe 1, for example, by shotcrete method or by injection method.

In the injection method under pressure, both removable and non-removable formwork can be used, under which concrete mixture is pumped into the formed space between it, the pipe and the end caps under pressure.

Artificially created stress concentrators in the form of annular grooves 6 are applied to the surface of the concrete coating 3. The annular grooves 6 are applied, for example, by rolling by a roller (not shown) or by forming formwork grooves (removable or non-removable). The rolling step - K, is selected from the condition that it is sufficient to compensate for the emerging internal stresses in the concrete 3 coating. Grooves 6 can be applied to the concrete 3 coating spirally.

It was experimentally established that for the ∅159-550 mm pipeline, the pitch K is 500 mm - 800 mm; for pipeline ∅550-820 mm, pitch K is 800 mm - 1200 mm; for the ∅820-1420 mm pipeline, the pitch K is 1200 mm - 2000 mm with a concrete coating thickness of 45 mm.

With an increase in the thickness of the concrete coating for every 15 mm, step K decreases by 10%. This is true for a pipe bending radius of 1200 D. For smaller bending radii, pitch K decreases by 5% with a decrease in radius for every 100D.

The thickness of the applied concrete 3 coating on the pipe 1 with cable channels 5 depends on the operational requirements and the requirements of SNIP and SP for the operation, manufacture and installation of pipes with concrete coating. Moreover, it ranges from the full coverage of cable channels 5 in the thickness of the concrete 3 coating (Fig. 4), to the value of the required operational safety (Fig. 5).

In cases where the use of reinforcing cage 4 is required, the thickness of the concrete 3 coating is selected from the condition that the reinforcing cage 4 is fully covered in its thickness (Fig. 4), or to the value of the required operational safety (Fig. 5).

The pipe 1 can be made, for example, of metal, or polymer, or metal-plastic, or composite. In turn, the reinforcing cage can be made in the form of a mesh, for example, of metal, or polymer, or composite.

When mounting a pipe 1 with a concrete 3 coating, internal stresses arise in it and when the tensile strength of the concrete 3 coating is exceeded, the latter gives cracks in artificially created stress concentrators in the form of ring grooves 6 (Fig. 10, Fig. 11), which prevent the unpredictable chipping and ensures the safety of installation work. In addition, the compensation of internal stresses in the concrete 3 coating due to bending due to the formation of predicted cracks prevents the possibility of possible crushing or rupture of the cable channels 5.

When the pipe 1 is a longitudinal seam welded pipe on which a reinforcing cage 4 is mounted with cable channels 5 located under it, the placement of the cable channels is oriented relative to the weld.

Artificially created stress concentrators in the form of annular grooves 6 (Fig. 1 of Fig. 2) are made on the outer surface of the concrete 3 coating. The annular grooves 6 are made with a step - K, sufficient to compensate for the emerging internal stresses when bending the pipe 1 with a concrete 3 coating.

Artificial stress concentrators can also be made in the form of grooves 6 spirally applied to the surface of concrete 3 coatings (Fig. 3).

When applying concrete 3 coatings to the pipe 1, the cable channels 5 are placed (positioned) above the longitudinal weld 7 of the pipe 1 on both sides. (Fig. 8). In this case, the cable channels 5 are placed under the reinforcing frame 4. The reinforcing frame 4 can be made in the form of a grid (not shown), for example, metal, polymer or composite.

Concrete 3 pipe coating can be made of concrete mixture with nanomodifying additives.

When installing the pipeline (Fig. 1), the pipe 8 is welded to the earlier mounted pipe 1, while according to GOST 10706-76 p. 1.7 and (ST SEV 489-77) the longitudinal welds of these pipes 1 and 8 must be at a certain distance from each other friend - A (Fig. 9). And since when welding pipes 1 and 8 to each other, their cable channels 5 were positioned relative to the longitudinal weld from both sides along the longitudinal seams of pipes 1 and 8, then cables 9 of the communication and monitoring systems are passed through them with minimal losses . So in the case of using communication systems and monitoring two cables from three cable channels 5, then cable channels 5 are selected according to the following scheme: central plus left - central plus left - central plus right. If one channel cable is used, then the left-center-right channel-cable-5 scheme is used. Using the positioning of cable-channels 5 relative to the longitudinal weld of pipes 1 and 8 can significantly reduce the loss of cables 9 of the communication and monitoring systems.

After welding the pipe 8, a thermoplastic material 10 is applied to the joint assembly (Fig. 1), which is then heated, as a result of which it lies tightly on its outer surface. The shell 11 is fixed and the polyurethane foam is injected into the formed space.

When installing a pipe with a concrete 3 coating, internal stresses arise in it due to the presence of a bend (Fig. 10).

When exceeding the tensile strength of concrete 3 coatings for bending, the latter gives cracks in artificially created stress concentrators in the form of annular grooves 6 (Fig. 11), which prevent unpredictable chipping, and ensure the safety of installation work. Grooves can be applied to the outer surface of the concrete pavement - spirally. Spiral grooves reduce the time it takes to groove the surface of a concrete pavement.

In addition, the compensation of internal stresses in the concrete coating as a result of bending due to the formation of predicted cracks prevents the possibility of possible crushing or rupture of the cable channels 5.

The application of grooves 6, both circular and spiral, on the outer surface of the concrete 3 coating, can be carried out by rolling roller. This method can be implemented when applying concrete mixture by shotcrete method. When using the method of injection of concrete mixture, the formation of grooves can be carried out by the presence of a recess 12 (knurling) on a removable shell 13 (Fig. 12).

In order to increase the strength of concrete 3 coatings, it can be equipped with a reinforcing cage 4, and is made of concrete mix with nano-modifying additives. The reinforcing frame 4 can be made in the form of a mesh, for example, metal, polymer or composite.

To increase the degree of protection of the cable channels 5, they are placed under the reinforcing frame 4 of the concrete 3 coating.

Two or more cable channels 5 can be fixed to the pipe 1.

The proposed technical solution to the problem allows:

- to ensure the safety of work in the installation area of the pipeline, using artificially created stress concentrators in the form of ring grooves, made on the outer surface of the concrete coating;

- reduce the number of unpredictable chips and losses of concrete pavement and thereby reduce the amount of repair work;

- reduce the cost of cable communication systems and monitoring due to the positioning of the cable channels relative to the longitudinal weld of the conductive pipe;

- increase the level of protection of cable channels from external mechanical damage, by placing it under a reinforcing layer, and manufacturing a concrete coating from a mixture with nanomodified additives.

Claims (12)

1. A method of manufacturing a pipe with a cable channel and a continuous concrete coating, comprising installing and securing at least one cable channel to the pipe, applying a concrete coating to the pipe, in which the concrete coating is applied until the cable channels are completely covered in thickness, and Artificially created stress concentrators are applied to the surface of the concrete coating in the form of annular grooves with a step sufficient to compensate for the internal stresses arising in the concrete. 2. The method according to p. 1, in which the concrete coating is applied by gunning. 3. The method according to p. 1, in which the concrete coating is applied by winding. 4. The method according to p. 1, in which the concrete coating is applied by injection under pressure, for which the formwork is pre-installed on the pipe. 5. The method according to p. 1, wherein a reinforcing cage is mounted on the pipe, under which the cable channels are fixed. 6. The method according to p. 1, wherein a reinforcing cage is mounted on the pipe, on which the cable channels are fixed. 7. The method according to p. 5 or 6, wherein the concrete coating is applied until the reinforcing cage is completely covered in its thickness. 8. A pipe with a cable channel with a concrete coating, comprising a pipe with at least one cable channel installed on it and a concrete coating with applied stress concentrators in the form of ring grooves, characterized in that the ring grooves are made on the outer surface of the concrete coating of the pipe with step sufficient to compensate for internal stresses arising. 9. A pipe with a cable channel with a concrete coating, including a pipe with a cable channel installed on it and a concrete coating with applied stress concentrators in the form of ring grooves, characterized in that the pipe is longitudinally seamed and at least a second cable is additionally installed on the pipe a channel, wherein the cable channels are installed on both sides relative to the pipe seam and the number of cable channels on one side is not less than the number of cable channels on the second side of the seam, the grooves are made on the outer surface of the concrete covering the pipe with a step sufficient to compensate for the emerging internal stresses. 11. The pipe according to claim 9 or 10, characterized in that the concrete coating is made of concrete mixture with nanomodified additives. 12. The pipe according to claim 9 or 10, characterized in that the pipe is equipped with a reinforcing cage. 13. The pipe according to p. 12, characterized in that the cable channels are installed under the reinforcing cage.

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