AU2011322539A1

AU2011322539A1 - Method for the underground installation of a pipe.

Info

Publication number: AU2011322539A1
Application number: AU2011322539A
Authority: AU
Inventors: Hans-Jurgen John
Original assignee: T I C Tech Innovation Consulting Ag
Current assignee: Tic Technology Innovation Consulting AG
Priority date: 2010-10-29
Filing date: 2011-10-28
Publication date: 2013-06-06
Also published as: CA2815739A1; EP2447462A1; WO2012056011A1

Abstract

In a method for the underground placement of a pipeline (20) of a specified diameter between a starting side (2) and a target side (4), a pilot drill hole (16) is first created from the starting side (2) to the target side (4), a drilling head being moved forward by means of drilling rods (12). Optionally, the pilot drill hole (16) can be enlarged to a diameter that is smaller than a specified end diameter in one or more steps using a reamer. A reamer (30) that is configured to the end diameter of the drill hole (50) is assembled on the target side (4) and coupled to the pipeline (20) that is provided on the target side (4) by means of a coupling device. The reamer (30) and the pipeline (20) are subsequently moved from the target side (4) to the starting side (2), wherein the reamer (30) enlarges the drill hole (50) to the end diameter and the pipeline (20) comes to rest in the drill hole (50).

Description

WO 2012/056011 PCT/EP2011/069017 Method for the underground installation of a pipe The invention relates to a method for the underground installation of a pipe, which is suitable in particular 5 for pipeline construction. In the known HDD ("Horizontal Directional Drilling") method, a pilot hole is created from a start side to a target side by way of drill rods. Once the target side 10 has been reached, what is known as a reamer is mounted on the drill head or the drill bit. This reamer is then pulled, rotating, to the start side, with a suitable drilling fluid (for example bentonite) emerging at the tip of the rods, said drilling fluid both detaching the 15 soil that is present and supporting the drilled hole that is produced against collapse. The reamer passes are repeated with increasingly large reamers until the drilled hole has been produced with the desired size. In this case, the established drilled-hole diameter is 20 considerably larger than the diameter of the product pipe run to be subsequently installed. The considerable excess diameter is necessary in order to reduce the frictional forces during the installation process. The lubricating effect of a bentonite suspension on the one 25 hand and the floating of the product pipe run with low casing friction against the wall of the drilled hole on the other hand require an ample distance from the pipe wall to the wall of the drilled hole. 30 The success of the HDD method depends on particular geological conditions and the ultimate size of the drilled hole. In the case of a product pipe having a diameter of 56" (1.42 m), a drilled hole having a diameter of 1.80 m is produced. In the event of 35 failure, the drilled hole has to be abandoned. The method described in EP 1 802 844 B1 ("easy long") is a microtunneling method for pipeline construction, in which steel support pipes are advanced in the WO 2012/056011 - 2 - PCT/EP2011/069017 microtunneling method from a start side to a target side. Once the support pipe run has reached the target side, the product pipe run provided in the region of the target side (that is to say the pipe) is connected 5 to the support pipe run and is pulled or pushed into the drilled hole created with support. This method is reliable in any geology, since the wall of the drilled hole cannot collapse on account of the support pipes, but is slower and more expensive than the HDD method on 10 account of the advancement of the microtunnel. The borehole produced has a slightly larger diameter than the installed product pipe. Less soil is excavated and less bentonite is used than in the HDD method. The "easy long" method is thus more ecological than the HDD 15 method. It is the object of the invention to create a method for the underground installation of a pipe, which can be carried out at a similar speed to the HDD method but 20 is fundamentally more reliable and ecological. This object is achieved by a method for the underground installation of a pipe having the features of claim 1. Advantageous embodiments of the invention can be found 25 in the dependent claims. In the method according to the invention, a pipe having a given diameter is installed underground between a start side and a target side. First - in a similar way 30 to the HDD method - a pilot hole is created, wherein a drill head (preferably having a drill bit) is advanced from the start side to the target side by means of drill rods. In order to drive the drill rods, use can be made of what is known as an HDD rig, as is known 35 from the HDD method and is constructed at the start side. By way of the HDD rig, the drill rods can be rotated, advanced in the direction of the target side WO 2012/056011 - 3 - PCT/EP2011/069017 and, if required, moved back in the direction of the start side. The next method steps take place optionally, 5 specifically when the pilot hole is not intended to be widened to the desired final diameter (which is at least as large as the diameter of the pipe) in a single step. In these optional method steps, the pilot hole is enlarged in one or more steps, by means of a reamer 10 that is moved from the target side to the start side using the drill rods, to a diameter of the drilled hole which is smaller than the final diameter of the drilled hole, as is explained in more detail below. 15 Once the pilot hole has been produced or after the optional method steps have been carried out, the drill rods extend as far as the target side. A reamer configured for the final diameter of the drilled hole is now mounted at the target side, for example at the 20 drill head or at the end of the drill rods. The pipe provided at the target side beforehand or in parallel with the previous method steps is coupled to the reamer or to the end of the drill rods or the drill head. To this end, use is made of a coupling device between the 25 reamer and the end of the pipe. Subsequently, the reamer and the pipe are moved from the target side to the start side. In the process, the reamer enlarges the drilled hole to the final diameter and the pipe comes to rest in the drilled hole. 30 Reamers are also used in the HDD method. With the aid of a reamer, soil which is not too hard can be cleared away. Preferably, the reamer is rotated while it is being moved from the target side to the start side 35 using the drill rods. Furthermore, the procedure is generally made considerably easier if a drilling fluid is introduced into the drilled hole, for example via nozzles arranged on the reamer, while the reamer is WO 2012/056011 - 4 - PCT/EP2011/069017 being moved from the target side to the start side. The drilling fluid preferably includes a bentonite suspension. 5 If, during the optional method steps, the pilot hole is enlarged to a drilled-hole diameter which is still less than the final diameter, the previously indicated intermediate steps can be carried out. To this end, a reamer is pulled from the target side to the start side 10 by means of the drill rods, wherein the reamer enlarges the pilot hole. This reamer creates a drilled-hole diameter which is less than the final diameter. If the drilled hole needs to be enlarged further in a stepwise manner, for example on account of the size of the final 15 diameter or the nature of the soil, the drilled rods are advanced to the target side again and then a larger reamer is pulled from the target side to the start side by means of the drill rods, wherein the larger reamer further enlarges the previously created hole. If 20 appropriate, this step is repeated once or more than once with increasingly large reamers. Finally, the drilled rods are advanced to the target side again in order to take up the starting position which is necessary for the previously explained steps for 25 producing the final diameter of the drilled hole and introducing the pipe into the drilled hole. In order to enlarge the reamer, a larger reamer is preferably mounted each time. In principle, it is also 30 conceivable to use an adjustable reamer which can if necessary be adjusted to such an extent that it is configured for the final diameter. If a reamer is configured for a particular diameter, this does not necessarily mean that it itself has to have this 35 diameter. On account of the effect of the drilling fluid, the reamer may also be smaller.

WO 2012/056011 - 5 - PCT/EP2011/069017 As a rule, the drilled hole will have a smaller diameter than the pipe prior to the employment of the reamer configured for the final diameter. However, applications in which the drilled hole is widened to 5 such an extent that its diameter is already larger beforehand are also conceivable in principle. In preferred embodiments of the method according to the invention, the pipe is advanced from the target side to 10 the start side using a pushing apparatus arranged at the target side. Pushing apparatuses that are suitable for such a purpose (for example "pipe thrusters") are known and can in principle exert large pushing forces, for example when a hydraulic apparatus acts on the 15 outer wall of the prepared pipe by means of a sheath like collar. If the pipe is strong under tension and can be moved relatively easily through the drilled hole, it is also conceivable, however, to pull the pipe from the target side to the start side with the aid of 20 the drill rods. If a pushing apparatus is used, the moving of the reamer configured for the final diameter to the start side using the drill rods and the activity of the 25 pushing apparatus are preferably synchronized with one another such that the movements take place as far as possible at the same basic speeds and do not have to be adapted to one another by forces transmitted from the pipe and from the drill rods. 30 The coupling device advantageously has a rotary coupling and also a device for acting on the end of the pipe. The pipe is not intended to rotate about its longitudinal axis as it is being introduced into the 35 ground, while the reamer rotates. The rotary coupling serves for compensation.

WO 2012/056011 - 6 - PCT/EP2011/069017 Since, during the installation of the pipe, the distance between the reamer and the end of the pipe is small, the drilled hole does not as a rule collapse. However, depending on the local geology, a support 5 casing may if necessary be carried along in the intermediate space between the reamer and the end of the pipe while the reamer and the pipe are being moved from the target side to the start side, said support casing preventing the drilled hole from collapsing. In 10 this case, the diameter of the support casing is matched to the diameter of the pipe, i.e. for example is the same size or somewhat larger. As already mentioned, the pipe is prepared prior to 15 being moved into the drilled hole at the target side. To this end it may already be fully prepared, for example welded together from individual pipes and if necessary provided with corrosion protection, and also checked. The pipe may be mounted for example on a 20 roller track on the target side. The pipe may be used for transporting media, but may also be in the form of an empty pipe, for example for the subsequent pulling in of cables. 25 The method according to the invention, which may be known as the HDJ ("Horizontal Directional Jacking") method, combines the advantages of the HDD method and of the "easy long" method. The drilled-hole diameter needs to be only slightly larger than the diameter of 30 the pipe to be installed, since as a rule a lubricating film (for example composed of bentonite suspension) suffices to reduce the casing friction. The HDJ method is more economical than the "easy long" method and more reliable and ecological than the HDD method. 35 The invention is explained in more detail in the following text by way of exemplary embodiments. In the drawings: WO 2012/056011 - 7 - PCT/EP2011/069017 Figure 1 shows a schematic longitudinal section through a construction site at which the method according to the invention is used, in 5 a first phase, Figure 2 shows a schematic longitudinal section through the construction site according to figure 1 in a second phase, 10 Figure 3 shows a schematic longitudinal section through the construction site according to figure 1 in a third phase, and 15 Figure 4 shows a schematic longitudinal section through an embodiment of a reamer which is connected to drill rods and to which the end of a pipe is coupled by means of a coupling device, during the construction phase 20 according to figure 3. Figures 1 to 3 illustrate in schematic longitudinal section various phases during the execution of an exemplary embodiment for a method for the underground 25 installation of a pipe. The arrangement of the construction site can be seen in figure 1. A pipe is intended to be laid under a body of water 6 between a start side 2 and a target side 4. An 30 HDD rig 10 is constructed and anchored on the start side 2. HDD rigs are used in HDD methods and are familiar to a person skilled in the art. With the aid of an HDD rig, drilled rods can be rotated and advanced and also pulled back under force exertion. In the 35 exemplary embodiment, a pilot hole 16 which leads to the target side 4 and sets the subsequent course of the pipe to be installed is created with the aid of the HDD rig 10, drilled rods 12 driven thereby and a drill head WO 2012/056011 - 8 - PCT/EP2011/069017 14 mounted at the end of the drill rods 12. The drill head 14 is controllable such that the pilot bore 16 can be guided along a curved and previously defined path. In the view shown in figure 1, the drill head 14 has 5 just arrived underneath the body of water 6. While the pilot hole 16 is being created, the pipe to be installed, which is designated 20, is prepared on the target side 4. In the exemplary embodiment, the 10 pipe 20 is welded together from steel pipe sections, the region of the weld seams is provided with corrosion protection, and a leak-tightness check is carried out. A liquid or gaseous medium can subsequently be transported through the pipe 20. Other configurations, 15 for example in the form of an empty pipe or a pipe made of some other material, are likewise conceivable. As can be seen in figure 1, the pipe 20 is mounted on a roller track 22. Furthermore, what is known as a pipe 20 thruster has already been moved into position. The pipe thruster has a pipe clamping device 24 which acts on the outer side of the pipe 20 via a type of collar and in the process can exert large forces. The pipe clamping device 24 is connected to an anchoring means 25 28, schematically shown in figure 1, via advancing cylinders 26. By actuating the advancing cylinders 26, the pipe 20 can subsequently be advanced in the direction of the start side 2. 30 Figure 2 illustrates a state in which the pilot hole 16 has been finished and after the drill head 14 has arrived at the target side 4. The drill head 14 is then removed from the drill rods 12 and a reamer 30 is mounted instead at the front end of the drill rods 12. 35 The reamer 30 is subsequently connected to the end of the pipe 20 by means of a coupling device. The reamer 30 and the coupling device are illustrated in figure 4 in an enlarged view (wherein the coupling device is WO 2012/056011 - 9 - PCT/EP2011/069017 configured in a slightly different manner than in figures 1 to 3). Reamers such as the reamer 30 are known in the prior 5 art from HDD methods. The reamer 30 has a larger diameter than the drill head 14. In the exemplary embodiment, the reamer 30 is fitted on the end of the drill rods 12 instead of the drill head 14. However, it is also conceivable for the drill head 14 to be left on 10 the drill rods 12 and for the reamer 30 to be fastened to the drill head 14. With the aid of an attack side 32, which is configured in a conical manner in the exemplary embodiment, the reamer 30 can widen the drilled hole, when it is rotated with the aid of the 15 drill rods 12 and pulled toward the start side 2. In the process, a drilling fluid, a bentonite suspension in the exemplary embodiment, emerges on the attack side 32, said drilling fluid making it easier to widen the drilled hole, strengthening the wall of the drilled 20 hole and simultaneously acting as a lubricating film. The reamer 30 is connected to the pipe 20 via the coupling device. As figure 4 shows, this coupling device has a joint part 34, a rotary coupling 36, a 25 further joint part 38 and also a strain-relief means 40. The strain-relief means 40 is mounted on the end of the pipe 20 and is subsequently removed when the pipe has 20 has been finally laid. 30 Figure 2 therefore shows the state of the construction site immediately after the mounting of the reamer 30 and the coupling device 34, 36, 38, 40. The reamer 30 is now pulled in the direction of the start side 2 via the drilled rods 12 with the aid of the HDD rig 10, 35 while the pipe thruster is set into action and simultaneously advances the pipe 20 with the aid of the advancing cylinders 26. In the exemplary embodiment, the movements of the drill rods 12 and the advancing WO 2012/056011 - 10 - PCT/EP2011/069017 cylinders 26 are synchronized in order to avoid unnecessary tensile or compressive forces in the drill rods 12 and the pipe 20. Figure 3 shows a state in which the reamer 30 has arrived under the body of water 5 6. The region of the reamer 30 having the end of the pipe 20 is, as already explained, illustrated in figure 4 in an enlarged view. While the reamer 30 is being rotated by the drill rods 10 12 and the drilling fluid is emerging on the attack side 32 of the reamer 30, the reamer 30 widens the drilled hole 50 which is generally designated 50. As a result, the pilot hole 16, the wall 52 of which has a first diameter, is enlarged in the exemplary embodiment 15 to a drilled hole having a wall 54 which already has the desired final diameter. The reamer acts in particular at a transition zone 56. The rotary coupling 36 ensures that the reamer 30 can rotate without problems, while the pipe 20 executes no rotary 20 movement. The drilling fluid also passes into an intermediate space 58 between the pipe 20 and the wall 54 of the drilled hole 50 and forms there a type of lubricating film which considerably reduces the frictional forces between the pipe 20 and the wall 54 25 of the drilled hole 50. The reamer 30 is pulled back as far as the start side 2, while the pipe 20 is advanced, such that the pipe 20 comes to rest along the desired route in the final 30 state. It is assumed in the exemplary embodiment that the soil, in particular after the drilling fluid has acted, is so firm that the drilled hole 50 does not collapse 35 in the region between the reamer 30 and the strain relief means 40 of the pipe 20. If the soil is problematic, a support casing can be arranged in this zone, the outside diameter of said support casing WO 2012/056011 - 11 - PCT/EP2011/069017 corresponding to the final diameter of the drilled hole 50 or having a slightly smaller diameter. The support casing prevents the drilled hole 50 from collapsing in this critical region and is moved together with the 5 pipe 20 toward the start side 2. In the exemplary embodiment, the pilot hole 16 is widened in one step with the aid of the reamer 30 to the final diameter (wall 54) necessary for the pipe 20. 10 Depending on the nature of the soil and the diameter of the pipe to be introduced, however, intermediate steps can also be carried out. To this end, first of all a reamer having a smaller diameter than that of the reamer 30 is mounted after the pilot hole 16 has been 15 produced and is pulled without the pipe 20 toward the start side 2, with the drilled hole 50 being widened. Subsequently, the drilled rods 12 are moved back to the target side 4 with the aid of the HDD rig 10. There, if required, a larger reamer can be attached, said larger 20 reamer still being smaller than the reamer 30, in order to carry out a further intermediate step for widening the drilled hole 50. If necessary, this process is repeated once again or more than once, until finally the reamer 30, which creates the desired final diameter 25 of the drilled hole 50, can be mounted.

Claims

1. A method for the underground installation of a pipe of a given diameter between a start side and 5 a target side, having the steps of: - producing a pilot hole (16) from the start side (2) to the target side (4), wherein a drill head (14) is advanced by means of drill rods (12), - optionally enlarging the pilot hole (16) in one 10 or more steps, by means of a reamer that is moved from the target side (4) to the start side (2) using the drill rods (12), to a diameter of the drilled hole (50) which is smaller than a final diameter, wherein the final diameter is at least 15 as large as the diameter of the pipe (20), - mounting a reamer (30) that is configured for the final diameter at the target side (4), and coupling the pipe (20) provided at the target side (4) by means of a coupling device (34, 36, 38, 40) 20 between the reamer (30) and the end of the pipe (20), - moving the reamer (30) and the pipe (20) from the target side (4) to the start side (2), wherein the reamer (30) enlarges the drilled hole (50) to 25 the final diameter (54) and the pipe (20) comes to rest in the drilled hole (50), - wherein the pipe (20) is moved from the target side (4) to the start side (2) using a pushing apparatus (24, 26, 28) that is arranged at the 30 target side (4).

2. The method as claimed in claim 1, characterized in that the moving of the reamer (30) configured for the final diameter (54) to the start side (2) 35 using the drill rods (12) and the activity of the pushing apparatus (24, 26, 28) are synchronized with one another. WO 2012/056011 - 13 - PCT/EP2011/069017

3. The method as claimed in claim 1 or 2, characterized in that the optional enlargement of the pilot hole (16) is carried out and has the following steps of: 5 - pulling a reamer from the target side (4) to the start side (2) by means of the drill rods (12), wherein the reamer enlarges the pilot hole (16), - optionally moving the drill rods (12) to the target side (4) again and pulling a larger reamer 10 from the target side (4) to the start side (2) by means of the drill rods (12), wherein the larger reamer further enlarges the previously created hole, and optionally repeating this step once or more than once with increasingly large reamers, 15 - advancing the drill rods (12) to the target side (4) again.

4. The method as claimed in one of claims 1 to 3, characterized in that the reamer (30) is rotated 20 while it is being moved from the target side (4) to the start side (2) using the drill rods (12).

5. The method as claimed in one of claims 1 to 4, characterized in that a drilling fluid is 25 introduced into the drilled hole (50) while the reamer (30) is being moved from the target side (4) to the start side (2).

6. The method as claimed in claim 5, characterized in 30 that the drilling fluid is introduced into the drilled hole (50) via nozzles arranged on the reamer (30).

7. The method as claimed in claim 5 or 6, 35 characterized in that the drilling fluid includes bentonite. WO 2012/056011 - 14 - PCT/EP2011/069017

8. The method as claimed in one of claims 1 to 7, characterized in that the coupling device (34, 36, 38, 40) has a rotary coupling (36). 5

9. The method as claimed in one of claims 1 to 8, characterized in that a support casing is arranged in the intermediate space between the reamer (30) and the end of the pipe (20) while the reamer (30) and the pipe (20) are being moved from the target 10 side (4) to the start side (2), wherein the diameter of the support casing is matched to the diameter of the pipe (20).

10. The method as claimed in one of claims 1 to 9, 15 characterized in that the pipe (20) is fully prepared and checked prior to being moved into the drilled hole (50) at the target side (4).

11. The method as claimed in one of claims 1 to 10, 20 characterized in that the drilled hole (50) has a smaller diameter than the pipe (20) prior to the employment of the reamer (30) configured for the final diameter (54).