HK1136856A - Method for trenchless laying of pipelines - Google Patents

Description

The invention relates to a method for the pit-free laying of pipelines, whereby a controlled tube propulsion is conducted from a starting point under an obstacle to a target point.

There are numerous methods and devices for laying pipes in the ground without a pit. This can be used to cross areas of the terrain where laying in an open pit would be impossible, unfavourable or too expensive for various reasons. Examples of this are bodies of water, wetlands, rocks, nature reserves, a large depth of laying, a high groundwater level or dense construction.

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Although the controlled horizontal drilling technique has proved to be a reliable method in suitable soil formations, there are some disadvantages: for example, large working areas of several thousand square metres must be provided for the work to be carried out on both sides of the obstacle to be overcome, which is not always possible or is unfavourable for environmental reasons.

Furthermore, the HDD method causes problems for larger holes (e.g. of a diameter of more than 800 mm) in some soils (especially gravel, gravel or rocky soils with few binding parts) because the hole can not be supported before the pipe is drawn in, but can only be solidified with a pumped drill flush. This often fails to achieve the required stability, which results in collapses.

Another well-known method is microtunneling (MT), in which a controlled and, where necessary, curved bore is conducted from a starting shaft or a starting pit to a target shaft or a target pit. The pilot drilling, the widening and a push of the pipes are carried out in a single work step. The pipes are laid as forward tubes, which are not firmly connected to each other, since the pipe push from the starting shaft or the starting pit is carried out under press.

In the microtunneling process, the cost of leaving the mainly concrete-made forward pipes in the borehole is high, even if no concrete pipe is desired. In this case, the inserted concrete pipes can only serve as a blank pipe for an additional pipeline with product pipes. The use of steel or polyethylene pipes is possible in microtunneling, but uncommon due to technical difficulties.

The pilot tube drives are first driven with a relatively small diameter pilot drill, which is then extended in a further step to the desired end diameter of a borehole, while simultaneously pushing the pipe to be laid in from a starting shaft or pulling in from a target shaft. This procedure is generally limited to bore lengths of less than 100 m, with drilling being done in a straight line. The diameters of the pipes to be laid are in the range of about 100 mm to 1000 mm.

Another method combines elements of the microtunneling technique with the single-piece product line of the HDD technique by mounting a microtunneling machine at the top of the product line to be installed. This method is described in DE 10 2006 020 339 A1. A pusher is used to push a starting shaft from the prefabricated product line through the earth to a target point with the microtunneling machine at the top. This method allows a quick laying of the pipeline as the run-time during the pre-plumbing is significantly reduced.

The disadvantage of the method known from DE 10 2006 020 399 A1 is that steel pipes are difficult to control, so such a drive usually has to provide for a planned straight shift. Furthermore, no intermediate press stations (stretching stations) can be installed in the product line. This limits the length of the drive; experience is available up to about 500 m. Furthermore, no lubricating chips can be placed on the product line for continuous lubrication of the pipe walls. Therefore, a reduction in the coatings is only limited, which also has a possible effect on the maximum drill length of the process.

DE 10 2005 021 216 A1 describes a method for laying pipelines without a trench, whereby a controlled tube propeller is driven from a starting point under an obstacle to a target point. A borehead is pushed from the starting point towards the target point by means of support or propeller pipes, the resulting borehole being already extended to its final diameter and supported by the propeller pipes. The ground released by the borehead is hydraulically extracted from the borehole. When the front end of the propeller line has reached the target point, a connection point at the end of the target line is used to attach a product propeller (the end of the propeller line) to the front end of the propeller line, which is then drawn back into the borehole.

This method is very advantageous, since pre-mounted pipes with a diameter of about 800 mm to 1400 mm can be laid over large lengths (about 250 m to 750 m) in almost all types of soil and also in groundwater in a curved borehole, the wall of which is supported at all stages of the process.

The purpose of the invention is to develop a method for the pit-free laying of pipes which enables pipes of relatively large diameter (e.g. in the range of 800 mm to 1400 mm) to be laid over relatively large lengths of laying (e.g. in the range of 250 m to 750 m) at low cost, even in difficult types of soil (e.g. gravel, gravel or rock).

This problem is solved by a method for the pit-free laying of pipelines with the characteristics of claim 1 and by a method with the characteristics of claim 17.

The method of the invention for the pitless laying of pipelines involves a controlled forward movement of a pipe from a starting point under an obstacle to a target point. A borehead is then pushed from the starting point with support pipes towards the target point. The resulting borehole is already extended to its final diameter and supported by the support pipes during this work step. The ground released by the borehead is extracted from the borehole, e.g. hydraulically. A borehole, formed at least in partial sections, is then pre-stressed at the support pipes and moved through the borehole, with the support back out of the borehole.

When moving the pipe, the pipe is pushed through the borehole according to the invention by applying compressive forces. If the support line is not only compressive (in the axial direction) as required for the pushing of the support lines, but also attached, the insertion of the pipe can be supported by applying additional tensile forces to the pipe through the support line (see below), but this is only an option. In principle, the invention procedure can be performed using support lines designed only for the transmission of axial compressive forces. The existing support lines are usually made of steel and are the most cost-effective and useful as support lines, as described in the above procedure DE 1021 01, DE 216

It is advantageous if the pipeline is already assembled in long sections or even in its entire length. For example, in the case of steel pipes, the impacts can be welded, if necessary sealed and checked.

In an advantageous embodiment of the process, the pipeline pushes the supporting pipe through the borehole after being coupled to the supporting pipe string. The propulsion force to push the pipeline (axial pressure) can be applied with a push device over the shell surface of the pipeline. Such push devices are known. They are located on the side of the pipeline or surround the pipeline and attach to the outside of the pipeline, e.g. via a cuff.

It is conceivable to use support tubes in short lengths, with the next support tube being attached at the starting point to the existing support tube line if the respective rear support tube is advanced far enough, but it may be more advantageous to prefabricate the support tube line, at least in larger sections, as this allows for the pre-assembly of the lines, monitoring organs, lubrication devices (see below) and intermediate press stations (see below) necessary for operating the drilling rig. This reduces the setup times to a minimum during the drilling process.

In principle, the pipe can be connected to the rear support tube of the support tube string by simply hitting the front sides together, but it is more advantageous to use a connecting pipe which allows more even force distribution and, if necessary, the transfer of tensile forces.

If necessary, short sections of pipe (e.g. about 2.5 m long) can be fitted with jointed piping connections, which allows good controllability, both for the support line and for the pipeline (product line).

The pipeline, i.e. the product line, can be prepared at the start-point side of the method of the invention and moved from the start-point side into the borehole, which may offer significant advantages over the method already known from DE 10 2005 021 216 A1, in particular if there is not enough space at the target point for preparing the pipeline or if it is more advantageous for other reasons to concentrate the laying activities in the area around the start-point.

In this case, the pipeline can be connected to the support tube after the drill head has reached the target. Thus, the support tube extends the entire way from the starting point to the target. However, it may also be useful to connect the pipeline to the support tube before the drill head reaches the target. In this case, the support tube is shorter, saving labor time, but the borehole is not yet generated in its full length and the coupled pipeline may need to transfer greater pressure forces to the support tube. This variant is suitable, for example, in relatively soft soil.

Alternatively, the method of the invention may also prepare the pipe on the side of the target and move it from the side of the target into the borehole, whereby the pipe is coupled to the supporting pipe string after the drill head has reached the target. This is similar to the method known from DE 10 2005 021 216 A1, but in contrast the pipe is not moved by pulling from the starting point but by pushing from the target through the borehole. A similar (or even the same) propulsion device may be used for this purpose as for pushing the supporting pipes from the starting point. Whether it is more economical to insert the pipe from the starting point or from the target into the borehole depends on the individual.

As explained above, the starting point and the starting or the target point are pressurised on the support tube and the product tube. However, it is also conceivable to provide a traction device that can apply a pull force to the support tube after it has reached the target point. To do this, the individual support tubes in the support tube must not be pressurised but only pressurised and connected to each other. Furthermore, the connecting tube in question should be able to transmit pull forces. In principle, the entire pipe can then be drawn to the target point or starting point, depending on which side it is drawn.

The support tube can be dismantled at the target point (or, if it is moved back to the starting point, at the starting point) in sections, e.g. into individual support tubes.

A particular advantage of the method according to the invention compared to the method known from DE 10 2006 020 339 A1 (which does not use support pipes) is that a tension station (intermediate press station) can be installed between two adjacent support pipes. If necessary, a larger number of tension stations can be distributed over the support pipeline. The tension stations are known from the microtunneling processes. If the thrust forces when pushing the support pipeline along the transfer line exceed the possibilities of the pressure device or the pressure of the support pipeline, assistance tension stations can be used to bring the required tension force to the next starting point.

If many stretching stations are used, in principle an arbitrary length of forward travel between the starting point and the destination point is possible.

It is also advantageous to apply a lubricant (e.g. concrete) to the outside of the support line, preferably via a lubricating pad on at least one support line, which allows continuous lubrication during the forward movement of the support line and thus greatly facilitates the completion of the borehole.

Compared with the method known from DE 10 2006 020 339 A1, the method of the invention, while it is necessary to insert a supporting tube line first, also allows for considerably longer distances between the starting point and the target point, since the borehole is supported by the supporting tubes and the use of stretching stations and continuous lubrication is possible.

The starting point is preferably a construction pit (e.g. a flat construction pit), which facilitates the supply of larger lengths of a prepared pipeline or a prepared supporting pipe line. The target area can be, for example, in a construction pit or a shaft.

In addition, it is possible to install at least one intermediate shaft between the starting point and the target point, containing a device to apply tensile and/or compressive forces to the support line or pipe in order to facilitate the forward movement of the support line or pipe to the target point.

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The following illustrations illustrate the invention by means of examples of implementations. Figure 1 - Schematic representations of the principal applications of the method of the invention, namely in part (a) a drill line from a borehole as a starting point under an obstacle to a borehole as a target, in part (b) a drill line from a borehole as a starting point under an obstacle to a shaft as a target and in part (c) a drill line from a borehole as a starting point under an obstacle to a valley floor or a waterbed as a target,Figure 2 - Schematic representations of successive steps in a first example of the method of the invention, in which a drill line is called from a borehole under an obstacle to a hole,and in part (a) the starting situation, in part (b) the preparation of the borehole and the insertion of the support line to support the borehole, in part (c) the preparation for insertion of the prepared line, in part (d) the insertion of the line and the displacement of the support line and in part (e) the insertion of the line after completion,Figure 3Schematic representations of successive process steps in a second example of the method of the invention whereby a drill line is moved from a construction shaft under an obstacle to a target hole, and in part (a) the starting situation, in part (b) the insertion of the support line and the insertion of the support line,In part (c) the preparations for the insertion of the prepared pipeline, in part (d) the insertion of the push the line and the displacement of the support line and the pushed line into part (e) after completion; Figure 4 - Schematic representations of successive steps in a third embodiment of the process of the invention, where a line is drilled from a construction pit under an obstacle to a valley floor, namely: (a) the starting situation, (b) the formation of the borehole and the insertion of the support line to support the borehole, (c) the preparations for the insertion of the prepared pipe, (d) the insertion of the pipe and the displacement of the support line, and (e) the completion of the inserted pipe.Figure 5a variant of the first example, schematically shown by the procedure step as shown in Figure 2d,Figure 6a schematic representation of the essential machinery components for making the borehole before the introduction of the borehead and support pipes andFigure 7a schematic representation of the essential machinery components for pushing the prepared pipeline after the making and mechanical support of the borehole.

In Figure 1 the basic possibilities for the course of a pipeline laid according to the method of the invention are shown in a schematic manner by means of examples.

In the first example (Figure 1a), the procedure is carried out from a starting point 1 in a construction pit (start pit) 2 under an obstacle 9 in a given bore line 7 to a target point 3 in a near-surface target pit 4.

In the second example of the method, the bore line 7 runs from a starting point 1 in a starting shaft 2 under a barrier 9 to a target point 3 in a shallow target shaft 4 (i.e. shaft), see Figure 1b.

In the third example, the process is carried out from a starting point 1 in a starting well 2 in a given borehole 7 to a target point 3 that is free in the field without a prepared well, e.g. in a body of water 10 (as in Figure 1c) or in a valley or at the foot of a slope.

The following figure 2 shows in more detail how the first example is used.

As shown in Figure 2a, starting point 1 is in a relatively shallow launch well 2 and target point 3 is in a target well 4. First, on the site in front of the launch well 2, support tubes 11 (which can in principle have different lengths) are coupled to a tube 8 (support tube line). Before the launch well 2, but also in the launch well 2, a thrust device 5 is installed and anchored with a counter bearing 20.

The drill is then carried out with the aid of the drill 6 along a given drill line 7 which runs below an obstacle 9 as shown in Figure 2b. The drill head 6 is pushed by the thrust device 5 over the support tube 8 against the ground material as required for the drilling operation.

The drilling operation along the drill line 7 continues until the drill head 6 reaches the target point 3 in the target shaft 4, see Figure 2c. The support tube 8 now supports the full length of the drill hole 12. The drill head 6 is dismantled and removed.

A line 14 (product line) prepared at the starting side is now moved into the borehole, and in the area of starting point 1 the line 14 is connected to the support line 8 by means of a connecting element 13.

As shown in Figure 2d, the pipe 14 is then pushed into the prepared borehole 12 by means of the pusher 5 and the support line 8 is simultaneously pushed into the target well 4. On the target side, i.e. at the target point 3 or in its immediate or even wider vicinity, the individual elements of the support line 8 i.e. the support lines 11 are dismantled.

After the pipeline 14 has been completely pushed in from the launch well 2 to the target well 4, the connecting element 13 can also be dismantled. If necessary, the pipeline 14 is shortened in the area of the launch well 2 or the target well 4.

In a variant of this example, the pipe is prepared on the side of the target well 3 instead of the side of the starting point 1. First, the support line 8 is advanced until the condition shown in Figure 2c is reached. Then the drill head 6 is removed. Then a connecting piece is installed at the site of the drill head 6 through which the pipe assembled on the side of the target well 3 is connected to the support line 8. Now, with a pushing device near the target well 4 (similar to the pushing device 5 at the starting point 1 or with it), the pipe can be advanced to the starting point 1, with the support line 8 being dismantled at the starting point 1 and the drill line 8 can be dismantled from the starting hole 12.

If the support line 8 is attached, the line 14 can be pushed from one end of the hole 12 into the hole 12 as in the example and simultaneously pushed from the other end of the hole 12 into the hole 12 via the support line 8 as explained at the beginning, which can facilitate the process of pushing and pulling the line 14 into the hole 12, as illustrated in Figure 5 analogous to Figure 2d, where the same basic construction devices with 5 rear bearings are used at the starting point 1 and the target point 3 for pushing and pulling.

Figure 3 illustrates the second example, using the same reference marks for the same parts as before.

Starting point 1 is located in a launch well 2, while target point 3 is formed in a relatively deep target shaft 16. First, on the site in front of the launch well 2, support tubes 11 are coupled to a support tube string 8. Before the launch well 2, but also in the launch well 2, a thrust device 5 is installed and anchored with a counterweight 20. In the launch well 2, a drill rig with a drill head 6 is prepared. This is essentially a conventional microtunnel drill unit, as in the first example. The support tube string 8 is connected to the drill head 6. These steps are shown in Figure 3a.

As shown in Figure 3b, the drill head 6 drills a hole 12 along drill line 7 running under an obstacle 9 (here a river) with the wall supported by the supporting pipe line 8. The necessary compressive forces for the drill head 6 are transmitted by the thrust device 5 over the supporting pipe line 8. As before, the drill head 6 is measured in its position and controlled in its movement along the pre-planned drill line 7 according to the pre-known techniques of controlled pipe propulsion.

The drilling operation along the 7 line is continued until the 6 borehole reaches the target point 3 in the 16 shaft, see Figure 3c. There the 6 borehole is dismantled and removed, see Figure 3d.

Figures 3c and 3d also show how a line 14 prepared at the start is pushed into the borehole and connected to the support line 8 by means of a connecting element 13 and then the line 14 is pushed into the prepared borehole 12 with the pusher device 5 and the support line 8 is pushed into the target shaft 16 at the same time, where the individual elements of the shaft, the support lines 11, are dismantled, see Figure 3d and Figure 3e.

After the pipeline 14 has been fully pushed in from the launch well 2 to the target shaft 16, the coupling element 13 is dismantled.

The third example is illustrated by Figure 4.

This time, the starting point 1 is in a starting shaft 2 and the target point 3 is in a valley floor 10, which gives the target point 3 open access, see Figure 4a.

First, on the site of the launch well 2 support tubes 11 are coupled to a support tube 8; before the launch well 2, but also in the launch well 2, a thrust device 5 is installed and anchored with a counter bearing 20; further, in the launch well 2 a drill device with a drill head 6 is prepared; as before, this is essentially a conventional microtunnel drill unit.

The drill 6 is now drilled along the specified drill line 7 by means of the drill 6 being pushed forward by the thrust device 5 over the supporting pipe string 8.

The drilling operation along the drill line 7 shall continue until the drill 6 reaches the target point 3 in the valley floor 10, see Figure 4c.

A pipe prepared at the starting side 14 is now moved into the borehole and connected to the support line 8 by means of a connecting element 13 (see Figure 4c).

The tube 14 is pushed into the prepared borehole 12 by means of the pusher 5 and the borehead 6 and support tube 8 are pushed through the borehole 12 at the same time.

On the target side, the drill head 6 and support line 8 or its individual elements (support lines 11) are dismantled, see Figure 4d.

If the pipeline 14 is completely pushed in from launch shaft 2 to target 3, it may be shortened in the area of the launching shaft 2 and target 3, see Figure 4e.

A variant of the third example (as in the variant of the first example) prepares the pipe before the target point 3; the second example is less suitable for such a variant, since it is not possible to assemble a longer pipe in the target shaft 16.

Figures 6 and 7 show the main mechanical components for the execution of the process in an enlarged view.

In a starting well 2, the drill head 6 (drill device) is connected to the support tube 8 (in which conventional intermediate pressing or stretching stations 15 are installed in one or more places) by means of a connecting element 13 and is placed on a guide frame 22. The drill head 6 has a cutting wheel 27 as a cutting tool, which in the example is equipped with high-pressure nozzles. The free end area of the prefabricated support tube 8 is stored on rolls 21.

The drill rig 6 is supplied and controlled by power and control cables 18; fresh drill flush is directed by a feed line 17 to the drill rig 6 cutter, while a conveyor line 19 transports the drill flush loaded with drill bits out of the borehole.

The power and control cables 18 lead to a control stand 23 which simultaneously provides power. The feed line 17 connects the drill head 6 to a drill flush blender 24 equipped with a pump and delivers fresh drill flush to the drill head 6. The conveyor line 19 leads to a drill flush treatment plant 26 where the drill flush is cleaned from the drill bit. The drill flush can then be fed via a connecting line 25 back to the drill flush blender 24 so that a circuit is established. The drill flush can also be used as a lubricant and, when hot, can be delivered to numerous support tubes in the ring hole between 12 and 8 strings to ensure that a pre-drill is taken up and the drill bit is removed without any problems.

Figure 7 shows how the rear support tube 11 of support tube 8 is connected to the prepared tube 14 by means of a connecting element 13 (which may be of a different design than the previously mentioned connecting element 13). In the example, the propulsion device 5 in Figure 6 also directs the required forward forces to tube 14 so that tube 14 is pushed into borehole 12 and support tube 8 exits hole 12 at target 3.

The figures in Figures 6 and 7 are not true to scale. If the elasticity of the supporting pipe 8 or pipe 14 is low, large radii of curvature are recommended.

List of references:

1Starting point2Starting pit3Finishing point4Finishing pit5Pusher 6Borehead (drill) 7Bore line8Support line9Hindrance10Bottom of the valley (waterbed) 11Support pipe12Borehole13Connection element14Pipeline (product line) 15Intermediate pressing station (extender station) 16Destination shaft17Food line18Power and control cable19Pipeline20Reversal21Roll buckets22Guidance bearing23Controller with power supply24Borehole mixing system with pump connection25Borehole mixing system26Borehole spraying system27Borehole

Claims (17)

1. a method for laying pipelines without a trench, whereby a controlled flow of pipes under an obstacle (9) is directed from a starting point (1) to a target point (3), Other

   - where a borehead (6) is pushed from the starting point (1) by means of supporting pipes (11) towards the target point (3), and the resulting borehole (12) is already extended to its final diameter and supported by the supporting pipes (11) and the ground dislodged by the borehead (6) is carried out of the borehole (12).

   - where a line (14) is connected to the support line (8) formed by the support tubes (11) and is moved through the borehole (12) with the support tubes (11) coming out of the borehole, at least in sections,

   - characterized by the pressure exerted on the pipe (14) to be pushed through the borehole (12).
2. The test method described in claim 1 is characterised by the tube (14) pushing the tube (8) through the borehole (12) after being attached to the support tube (8)
3. The method described in claim 2 is characterised by applying the propulsion force to push the line (14) by means of a pusher (5, 20) over the liner surface of the line (14).
4. The test method described in claims 1 to 3 is characterised by moving the pipe (14) from the side of the starting point (1) to the borehole (12).
5. The method described in claim 4 is characterised by the coupling of the pipe (14) to the support pipe (8) after the drill head (6) has reached the target point (3).
6. The method described in claim 4 is characterised by the coupling of the pipe (14) to the support pipe (8) before the drill head (6) reaches the target point (3).
7. The test method described in claims 1 to 3 is characterised by moving the line (14) from the side of the target (3) into the borehole (12) and attaching it to the support line (8) after the drill head (6) has reached the target (3).
8. The test method described in claims 1 to 7 is characterised by the support line (8) being designed to transmit tensile forces and by the application of tensile forces to the support line (8) at the opposite end of the borehole (12) after coupling the support line (14) to the support line (8) so that the support line (14) is pushed into both the borehole (12) and the borehole (12).
9. The test method according to claims 1 to 8 is characterised by the cutting off of the drill head (6) after the target point (3) has been reached.
10. The method according to one of the claims 1 to 9 is characterised by hydraulically extracting the soil released from the bore (6) from the borehole (12).
11. The test shall be carried out in accordance with one of the following requirements:
12. The test method described in claims 1 to 11 is characterised by the application of a lubricant to the outside of the support tube (8) preferably via a lubricating nipple attached to at least one support tube (11).
13. A process according to one of the claims 1 to 12 characterised by the provision of a construction pit (2) at the starting point (1).
14. The test method is described in claims 1 to 13 and is characterised by the presence of a construction pit at target point (3).
15. The test method is based on one of the claims 1 to 13 and is characterised by the presence of a shaft (16) at the target point (3).
16. A process according to one of the claims 1 to 15 characterised by the placement of at least one intermediate shaft between the starting point (1) and the target point (3) containing a device designed to apply tensile and/or compressive forces on the support line (8) or the line (14) to facilitate the forward movement of the support line (8) or line (14).
17. a method for laying pipelines without a trench, whereby a controlled flow of pipes under an obstacle (9) is directed from a starting point (1) to a target point (3),

    - where a borehead (6) is pushed from the starting point (1) by means of supporting pipes (11) towards the target point (3), and the resulting borehole (12) is already extended to its final diameter and supported by the supporting pipes (11) and the ground dislodged by the borehead (6) is carried out of the borehole (12) and

    - the supporting tube (11) is attached to the supporting tube (8)

    - characterised by the connection of a pipe (14) at least in sections prepared on the side of the starting point (1) to the supporting line (8) after the drill head (6) has reached the target point (3), and by the application of tensile forces from the target point (3) to the supporting line (8) to draw the pipe (14) attached to the supporting line (8) into the borehole (12).