EP0908598A2 - Method for laying a conduit and conduit comprising a casing and a production tubing - Google Patents

Abstract

The line comprises prefabricated segments (7) each including a casing (1) and a product pipe. These are forced through the ground hydraulically, in succession. Before each advance, sections of product line are connected together. An Independent claim is included for the pipeline and its segments. A corrosion-protection covering is provided. The casing is steel-reinforced concrete; the product line is steel. The product line is welded, the casing sections are non-positively interlocked. Preferred features: Pressure is applied exclusively to the casing. A line segment (7a) has a rearward product pipe projection (9a). A second segment (7b) is lowered into the hole (8), the product pipe projecting (9b) forward. A corresponding casing projection (12) exists at the other end. Product pipe projections are welded. The second segment casing is advanced to contact and interlock with the first. The process is repeated as often as necessary. Additional features of the line include an elastic material with electrolytic conductivity, in the up to 3 mm annular interspace between the tubes, bonded to the casing. The product tube is externally-lubricated. The elastic material is continuous and spiraled-onto the product tube. In the casing there are cable channels, and/or channels for a material facilitating pressing.

Description

The invention relates to a method for laying a line that consists of a jacket pipe and a product pipe, the casing pipe from a starting pit to to a target pit using a hydraulic pneumatic or mechanical Pressing device is pressed through the soil. The invention further relates to a Pipe with a jacket pipe and a product pipe with an anti-corrosion coating is provided.

Jacket pipe / product pipe lines, for the transport of liquid or gaseous Substances, such as natural gas, are usually laid when the line is one Crosses railway line, road or waterway.

In most cases, the line cannot be laid in an open construction, but rather must be pressed through the ground to use the traffic routes not to interfere.

It is known from practice to use reinforced concrete jacket pipes from a starting construction pit to advance through the ground to a target pit. After that, the product pipe drawn into the casing tube. Jacket pipes are used, their diameter is significantly larger than that of the steel product tube. The jacket pipes are usually so large that they are accessible. The product pipe lies eccentrically in the Casing pipe. The remaining space between the product pipe and the casing pipe is closed, for example by a sealing sleeve or by means of masonry.

When pulling the product pipe into the jacket pipe, you can use the anti-corrosion coating Damage due to skids that are not stuck or damaged during retraction arise. It is also disadvantageous that the drawn product tube on electrical insulating spacers must be stored.

Experience has shown that permanent sealing of the annular space in the Practice can hardly be guaranteed. Even with correct construction and assembly cracks appear in the seal. These are caused by the aging of the sealing material and the dynamic load on the structure due to traffic loads, Soil and pipeline movements and fluctuations in the groundwater level.

The sealing of the jacket tube ends is further complicated by cable protection tubes, that must be carried in the casing tube.

If the closure of the casing tube is not permanently watertight, water can enter penetrate the space between the product tube and casing tube, so that the danger corrosion damage.

The space between the product pipe and the casing pipe can also be filled with cement become. However, there is the difficulty that pressure tests are practically not are more possible because the product pipe can no longer expand.

The invention has for its object, on the one hand, a time-saving and safe Process for laying a casing pipe and a product pipe To create management and on the other hand to provide a generic management, in which the product pipe when laying before mechanical damage and after the installation is protected against corrosion damage.

To achieve this object, the method according to the invention is characterized in that that segments consisting of a casing pipe and product pipe section manufactured and one by one pre-pressed through the soil, whereby adjacent product pipe sections with each other before each pre-pressing step get connected.

The process is time-saving because the pre-pressing of the casing pipe and product pipe section in one phase and not in succession. Because the product line is not must be pulled in later, there is no damage to the anti-corrosion coating. During the pressing process, the jacket tube protects the product tube from mechanical Damage from obstacles.

According to the invention, the pressing forces act exclusively on the casing tube. The Product pipe is not loaded, so that damage is avoided.

a) daß ein erstes Segment vorgepreßt wird, das an einem Ende einen Produktrohr-Überstand aufweist,

b) daß ein zweites Segment in die Startbaugrube eingebracht wird, das an einem Ende einen Produktrohr-Überstand und an dem anderen Ende einen im wesentlichen gleich großen Mantelrohr-Überstand aufweist,

c) daß die Produktrohr-Überstände der beiden Segmente verschweißt werden und daß das Mantelrohr des zweiten Segmentes verschoben wird, bis eine kraftschlüssige Verbindung an den Stoßstellen der Mantelrohrabschnitte des ersten und zweiten Segmentes erreicht wird und

d) daß die Schritte b) und c) bedarfsabhängig wiederholt werden.

An essential further development of the method consists in

a) that a first segment is pressed, which has a product tube protrusion at one end,

b) that a second segment is introduced into the starting pit, which has a product pipe protrusion at one end and a jacket pipe protrusion of essentially the same size at the other end,

c) that the product pipe protrusions of the two segments are welded and that the casing pipe of the second segment is moved until a positive connection is reached at the joints of the casing pipe sections of the first and second segments and

d) that steps b) and c) are repeated as required.

The invention also provides a line with a jacket tube and a product tube which is provided with an anti-corrosion coating. The line is marked through a plurality of segments, which consist of a tubular casing section made of concrete and a product pipe section made of steel, the product pipe sections welded and the jacket pipe sections are non-positively connected.

Since the product pipe section and the casing pipe section form a composite and the Casing pipe sections connected to each other practically watertight after laying the risk of corrosion damage is extremely low.

Since these casing tubes are protective tubes that are not suitable for inspection must be interpreted by people, others can when dimensioning Safety factors are used as for a walk-in casing pipe which is subsequently pulled in a product pipe. Therefore, the wall thickness of the jacket pipe section according to the invention be less.

An annular space is preferably formed between the casing pipe section and the product pipe section formed, the thickness of max. 3% of the outside diameter of the product pipe is. An elastic material is advantageously located in the annular space.

The annular space between the casing pipe section and the product pipe section is intended to be of fundamental importance Considerations should be kept as small as possible so the outside diameter of the overall system and thus the pressing resistance (negative skin friction) are as small as possible. This requirement also applies to the optimization of the casing tube wall thickness.

During pre-pressing, a final pressure test or later changes in load the casing pipe section and product pipe section move relatively to each other. The annulus must be designed so that these relative movements are not lead to impermissible constraints. The elastic material allows in a simple way and way these relative movements.

An advantageous embodiment of the invention is that the first to be installed Segment of the line has a product pipe protrusion at one end. Each additional segment has a product tube protrusion at one end and at the other opposite end of a jacket tube protrusion of substantially the same length on.

This design of the segments enables the product pipes in front of each Prepress step can be welded together. The jacket tube overhang enables moving the jacket pipe protrusion until a positive connection is reached at the joints of the jacket pipe sections.

The elastic material is preferably connected to the tubular casing section. Between the corrosion protection covering of the product pipe section and the elastic Sliding relative movement of the material is possible. This will avoid that the product pipe is loaded during the advance. The strains that go through the introduction of the propulsive force in the jacket tube will not arise on the Transfer product pipe.

Can advantageously between the elastic material and anti-corrosion coating a lubricant must be present in the product pipe. The displacement of the tubular casing section up to the non-positive connection with the preceding jacket pipe section this will make it easier.

According to a further advantageous feature of the invention, the elastic material electrolytic conductivity. This will make the cathodic more effective Corrosion protection not impaired.

A polyurethane composite foam is preferably used as the elastic material. The elastic material can be designed as a band-shaped endless material, that can be placed in a spiral around the product tube.

At least the side of the elastic tube facing the jacket tube is preferred Material liquid-tight.

An advantageous embodiment of the invention is that in the tubular section Cable channels and / or channels for a pressing aid are cast in the concrete.

The invention is described below with the aid of a preferred exemplary embodiment line according to the invention in connection with the accompanying drawing explained.

Fig. 1

einen Schnitt durch ein Segment, das aus einem Mantelrohrabschnitt und einem Produktrohrabschnitt besteht;

Fig. 2

eine schematische Darstellung des Vorpressens eines ersten Segmentes;

Fig. 3

eine schematische Darstellung der Verbindung und des Vorpressens von zwei Segmenten;

Fig. 4

eine schematische Darstellung des Vorpressens weiterer Segmente.

The drawing shows in:

Fig. 1

a section through a segment consisting of a jacket pipe section and a product pipe section;

Fig. 2

a schematic representation of the pre-pressing of a first segment;

Fig. 3

a schematic representation of the connection and pre-pressing of two segments;

Fig. 4

a schematic representation of the pre-pressing of further segments.

Fig. 1 shows a section through a segment, which consists of a tubular casing section 1 Reinforced concrete and a product pipe section 2 is made. At the product pipe section is a steel pipe for the transportation of natural gas.

The tubular casing section t contains a steel reinforcement, not shown. Between An annular space 3 is formed in the casing tube section 1 and the product tube section 2. whose thickness max. 3% of the outer diameter of the product pipe section 2.

In the annular space there is an elastic material 4 which is connected to the tubular casing section 1 is connected. A polyurethane composite foam is used as the elastic material used, which is designed as a band-shaped continuous material that spirals around the product pipe can be laid. The elastic material has an electrolytic conductivity in order not to impair the cathodic corrosion protection of the product pipe. The elastic material is on the side facing the tubular casing section Liquid-tight side.

Between the elastic material 4 and a corrosion protection covering 11 of the Product pipe section 2 is a lubricant, not shown.

In the concrete cross section of the casing pipe section 1, cable channels 5 and channels 6 are for a pressing aid, e.g. B. poured concrete.

The segments are prefabricated in a production facility and used for installation transported. The max. Segment length depends on the means of transport available from.

2 shows the pre-pressing process of a first segment 7a. The segment 7a is in a starting pit 8. A product pipe section 2a is from one Surround casing pipe section 1a. The segment 7a faces the excavation pit end up a product pipe protrusion 9a. The pressing forces of a not shown act hydraulic-pneumatic or mechanical pressing device on the segment 7a, and was exclusively on the tubular casing section 1a.

Depending on the diameter of the segment to be driven and the upcoming one At the bottom, the segment 7a can be closed by a closure 10. However, it is also possible that the bottom is pressed into the product tube open at the front and is removed later. Alternatively, a drill head can be used.

When the first segment 7a has been pre-pressed, a second segment 7b is inserted into the Starting pit 8 introduced. The second segment 7b faces the opposite end the first segment 7a is directed to a product pipe protrusion 9b and to the opposite one End of a substantially equal length of jacket pipe section protrusion 12 on.

In the next step, the product pipe protrusions 9a and 9b of the two segments 7a, 7b welded. Then the casing tube section 1b of the second segment 7b shifted until a positive connection at the joint of the casing pipe sections 1a, 1b is reached.

After the claw-tight connection of the casing pipe sections 1a, 1b, the line pressed again.

In Fig. 4 it is shown that a third segment 7c is introduced into the starting pit has been. The individual steps of the process are repeated as needed, until the first segment 7a has reached a target pit, not shown.

Modifications are possible within the scope of the invention without further notice. For example the line according to the invention can also be laid open.

Claims (14)

Method for laying a line consisting of a jacket pipe and a Product pipe exists, the casing pipe from a starting pit to one Target excavation using a hydraulic, pneumatic or mechanical Pressing device is pressed through the soil, characterized in that that segments (7) consisting of a casing pipe and product pipe section (1, 2) manufactured and pressed one by one through the soil be, with adjacent product pipe sections in front every prepress step. Method according to claim 1,
characterized,
that the pressing forces only act on the tubular casing sections (1). The method of claim 1 or 2
characterized, a) that a first segment (7a) is pressed, which has a product tube protrusion (9a) at one end b) that a second segment (7b) is introduced into the starting pit (8), which has a product pipe protrusion (9b) at one end and a jacket pipe protrusion (12) of substantially the same size at the other end, c) that the product pipe protrusions (9a, 9b) of the two segments (7a, 7b) are welded and that the jacket pipe section of the second segment is moved until a positive connection at the joint of the jacket pipe sections of the first and second segments (7a, 7b ) is reached, and d) that steps b) and c) are repeated as required. Line with a jacket pipe and with a product pipe which is provided with an anti-corrosion coating,
marked by
a plurality of segments (7), which consist of a casing pipe section (1) made of reinforced concrete and a product pipe section (2) made of steel, the product pipe sections (2) being welded and the casing pipe sections (1) being non-positively connected to one another. Segment according to claim 4,
characterized,
that between the casing pipe section (1) and product pipe section (2) an annular space (3) is formed, the thickness of which is a maximum of 3% of the outer diameter of the product pipe section and that there is an elastic material in the annular space (3). Segment according to one of claims 4 to 5,
characterized,
that the first segment (7a) of the line has a product pipe protrusion (9a) at one end. Segment according to one of claims 4 to 5
characterized,
that the second and each further segment (7b, c) at one end has a product pipe protrusion (9b) at the opposite end a substantially equal length of the tubular casing protrusion (12). Segment according to one of claims 5 to 7,
characterized,
that the elastic material (4) is connected to the tubular casing section (1). Segment according to one of claims 5 to 8,
characterized,
that a lubricant is present between the elastic material and the anti-corrosion covering of the product tube. Segment according to claims 5 to 9,
characterized,
that the elastic material has an electrolytic conductivity. Segment according to one of claims 5 to 10,
characterized,
that a polyurethane composite foam is used as the elastic material (4). Segment according to claim 11,
characterized,
that the elastic material (4) is designed as a band-shaped endless material that can be placed in a spiral around the product tube. Segment according to one of claims 5 to 12,
characterized,
that at least the side of the jacket tube section of the elastic material (4) is liquid-tight. Segment according to one of claims 5 to 13,
characterized,
that cable ducts (5) and / or ducts (6) for a pressing aid are cast in the casing pipe section in the concrete.

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