EP1992742A2

EP1992742A2 - Laying a foundation by vibrating and fluidizing

Info

Publication number: EP1992742A2
Application number: EP20080075495
Authority: EP
Inventors: Arie Jan Van Vliet
Original assignee: Gebr Van Leeuwen Harmelen BV
Current assignee: Gebr Van Leeuwen Harmelen BV
Priority date: 2007-05-16
Filing date: 2008-05-16
Publication date: 2008-11-19
Also published as: NL1033865C2; EP1992742A3

Abstract

The present invention relates to a method for inserting an anchor block into the ground (1) for laying a foundation, in particular for anchoring an engineering structure (2), comprising the steps of positioning a vibrating pipe (10) with a vibrating head (11) on the distal end, and introducing the vibrating pipe into the ground by means of a vibrating device (20). The characterizing feature of the method according to the invention is that during the insertion of the vibrating pipe (10) into the ground, in addition to the vibrating by means of a vibrating device (20), the ground around the vibrating head is also fluidized with a fluidization medium. The fluidization medium is fed through a fluidization channel (12) to the vibrating head (11) of the vibrating pipe (10). The fluidization medium flows out through at least one outflow aperture (17) at the level of the vibrating head and mixes with the soil around the vibrating head.

Description

The present invention relates to a method for inserting an anchor block into the ground for laying a foundation, in particular for anchoring an engineering structure, comprising the steps of positioning a vibrating pipe, also known as an anchor pipe, with a vibrating head on the distal end, and inserting the vibrating pipe into the ground by means of a vibrating device. Anchor blocks are used during engineering work for anchoring all kinds of engineering structures, such as laying a foundation of underwater concrete floors, quay walls, bank revetments, earth-retaining construction walls in construction pits, tunnels, bridges etc.
It is known in the prior art to insert anchor blocks using a vibrating pipe. The vibrating pipe is a long hollow steel pipe with a length of, for example, at least 10m and a diameter of, for example, at least 10cm. A vibrating head is provided on the distal end of the vibrating pipe, which vibrating head is designed for vibrating the vibrating pipe into the ground with a vibrating device. The proximal end of the vibrating pipe is designed for connection to the vibrating device.
Before the vibrating pipe is vibrated into the ground, the vibrating pipe is first positioned, so that the vibrating pipe can be inserted into the ground at the correct place and at a correct angle.
The vibrating device is immovably connected to the proximal end of the vibrating pipe. The vibrating device produces vibrations which act upon the vibrating head through the vibrating pipe. The vibrating causes the ground around the vibrating head to be displaced, and the vibrating pipe will sink into the ground.
A problem with vibrating a vibrating pipe into the ground is that the vibrations produced are propagated in the ground. The vibrations can then cause damage to surrounding constructions. Cracks can appear in constructions, or constructions can collapse, which can lead to high repair costs and/or dangerous situations.
Another disadvantage of vibrating a vibrating pipe into the ground is that the vibrating takes a relatively long time.
The object of the present invention is at least partially to overcome at least one of the abovementioned disadvantages, or to provide a practicable alternative. In particular, the object of the invention is to provide a quick, cost-saving and efficient method by which the risk of damage to surrounding constructions is reduced.
This object is achieved by a method for inserting an anchor block into the ground for laying a foundation of an engineering structure such as that defined in claim 1.
The characterizing feature of the method according to the invention is that during the insertion of the vibrating pipe into the ground, in addition to the vibrating by means of a vibrating device, the soil around the vibrating head is also fluidized with a fluidization medium. The fluidization medium is fed through a fluidization channel to the vibrating head of the vibrating pipe. The fluidization medium flows out through at least one outflow aperture at the level of the vibrating head and mixes with the soil around the vibrating head. Through the mixing of the soil with fluidization medium, the soil acquires the character of a liquid. The soil around the vibrating head is moistened, with the result that it softens and is easily penetrated. The vibration of the vibrating pipe will cause the vibrating pipe to sink into the mixture of soil and fluidization medium. This advantageously increases the speed of insertion of a vibrating pipe into the ground compared with a method in which a vibrating pipe is inserted into the ground by vibration alone.
The working principle of the sinking of the vibrating pipe in the method according to the invention is comparable to the quicksand principle. Quicksand has the character of a liquid. If a person accidentally walks into quicksand, he will sink to a certain depth in the quicksand. The person will sink further if he begins to move. This principle applies in a similar way when a vibrating pipe is inserted into the ground by the method according to the invention. Fluidizing the soil around the vibrating head produces a mixture which has comparable properties to those of quicksand, and setting the vibrating pipe in vibrating motion will make the vibrating pipe sink further into the mixture.
In the method according to the invention, for insertion of the vibrating pipe into the ground the vibrating pipe is vibrated and the soil is fluidized as well. The vibration and fluidization are preferably performed simultaneously, but it is also possible to vibrate and fluidize alternately during the insertion of the vibrating pipe into the ground.
A major advantage of the method according to the invention is that through the combination of vibration and fluidization during the insertion of the vibrating pipe into the ground, hardly any vibrations are now transmitted to the environment. This minimizes the risk of damage to buildings. Through the fluidization of the ground around the vibrating head, the vibrations produced are damped, and hardly any of the vibrations are now transmitted outside the volume of soil that has been fluidized.
A further advantage of vibrating the vibrating pipe into the ground is that the soil is compacted around the outside, the lateral surface, of the vibrating pipe by the vibrating movement. This is advantageous in the method according to the invention because it means that the mixture of soil and fluidization medium around the vibrating head is given little or no opportunity to flow away along the lateral surface of the vibrating pipe. In this way it is ensured that the fluidized mixture does not pass up through the vibrating pipe out of the ground. Little or none of the mixture of soil and fluidization medium is therefore washed away, which has an advantageous effect on the maximum obtainable tensioning power of the foundation means ultimately obtained by the method according to the invention.
In a preferred embodiment of the method according to the invention, the pipe cavity of the vibrating pipe is closed off at the proximal end during the fluidization. For the fluidization, the pipe cavity in the vibrating pipe can be used as the fluidization channel, but a fluidization channel is preferably provided on the outside of the vibrating pipe. The fluidization channel is preferably tubular and preferably extends along the lateral surface of the vibrating pipe. The fluidization channel is preferably immovably fixed on the lateral surface of the vibrating pipe over at least a part of the length. This can be achieved by, for example, a welded connection.
The fluidization channel is preferably in flow communication with the pipe cavity in the vibrating pipe at the level of the vibrating head. The fluidization medium then flows through the fluidization channel along the lateral surface of the vibrating pipe and subsequently passes through the pipe wall of the vibrating pipe to the pipe cavity inside the vibrating pipe. Closing off the pipe cavity of the vibrating pipe above the vibrating head means that the fluidization medium can now flow out only through an outflow aperture at the level of the vibrating head.
In a particular embodiment of the vibrating pipe, particularly for use in the method according to the invention, a convex plate with at least one aperture is provided in the pipe cavity of the vibrating head. The convex plate with the aperture can be fixed on the vibrating head by means of at least one strip. The aperture serves as the outflow aperture. The direction of the outflowing fluidization medium can advantageously be determined by the aperture in the convex plate. In this way the soil around the vibrating head can effectively be mixed with fluidization medium.
In a preferred embodiment of the method according to the invention, after the vibrating pipe has been inserted into the ground, a hardening substance is fed in towards the vibrating head. The hardening substance leaves the vibrating pipe near the vibrating head, forming a hardened volume there. The hardening substance is preferably introduced through a fluidization channel on the outside of the vibrating pipe, through which the fluidization medium has been added in an earlier step. The fluidization channel has a smaller internal diameter of at most 40mm, so that the pressure loss during the introduction of hardening substance can remain low. The hardened volume around the vibrating head contributes to the ultimate tensioning power of the anchor block.
It has been found that through the introduction of the vibrating pipe according to the invention by both vibrating and fluidizing, a positive contribution is made to the formation of the hardened volume.
On the one hand, it has been found that through fluidization of the soil around the vibrating head, the volume of hardened substance formed is greater than it would be if the vibrating pipe were inserted into the ground without fluidizing. By fluidizing the soil, in which case the soil behaves like a liquid mass, it appears that the introduced substance can spread better around the vibrating head.
On the other hand, the vibration during the insertion of the vibrating pipe advantageously has a positive effect on the formation of the hardened volume. Vibrating the vibrating pipe into the ground ensures that the soil is compacted around the lateral surface of the vibrating pipe. This is advantageous when hardening substance is introduced under pressure, because the compacted soil ensures that little or none of the hardening substance can flow up along the lateral surface of the vibrating pipe. The result is advantageously that the hardening substance is expediently placed around the vibrating head and a saving in material costs and time can be achieved.
A subsequent step in the preferred embodiment of the method according to the invention is the placing of a tension element in the introduced substance before the introduced substance has hardened. The tension element can also be placed through the vibrating pipe before starting with the introduction of hardening substance. The tension element can be, for example, a pole, possibly with extension pieces, a cable, a strand, a reinforcing bar etc. Strands are preferably used as the tension element, because strands are relatively cheap and easy to handle. After the introduced substance has hardened, the tension element is immovably connected to the hardened volume around the vibrating head.
In the preferred embodiment of the method according to the invention, the vibrating pipe is partially withdrawn while the hardening substance is being introduced. This produces in the ground a so-called grout body, preferably having a length of at least 7m and at most 20m. The size of the grout body depends, inter alia, on the soil composition and the desired tensioning power. The vibrating pipe is preferably set in vibration also during its withdrawal. The forces needed for withdrawing the vibrating pipe will advantageously be lower as a result of this vibration. Furthermore, the soil around the lateral surface of the vibrating pipe is compacted as a result, which contributes further to the tensioning power of the anchor block ultimately obtained.
When the vibrating pipe has been partially withdrawn, in the preferred embodiment of the method according to the invention the introduction of hardening substance is stopped and a flushing medium, such as water, is then fed through. The flushing medium ensures that on further full withdrawal of the vibrating pipe no residues of the introduced substance are left behind in the vibrating pipe. This is advantageous for the re-use of the vibrating pipe for subsequent anchor blocks. By feeding through flushing medium, which is preferably fed through the fluidization channel, the vibrating pipe has been flushed clean when it is fully withdrawn from the ground. The clean vibrating pipe is then advantageously directly available for placing a subsequent anchor block in the ground.
Furthermore, the feeding through of the flushing medium is advantageous because it prevents the hardening substance from flowing out over the surface of the ground in, for example, a construction pit when the vibrating pipe has been fully withdrawn. It is not desirable for hardening substance to come out of the hole in the ground that has been produced by the withdrawal of the vibrating pipe. Not only is the hardening substance on the ground surface wasteful, it also gives rise to further problems in the finishing of the engineering structure. For example, when inserting anchor blocks for laying a foundation of an underwater concrete floor in a construction pit, it is undesirable for hardening substance to be deposited on the concrete floor. When a finishing layer is being laid over the concrete floor, the lumps of hardened substance constitute pollutants which have an adverse effect on the quality of the finishing layer. Owing to the fact that after the partial withdrawal of the vibrating pipe, the introduction of hardening substance is stopped and there is further flushing with flushing medium, the risk of spilling and wastage of hardening substance on the ground surface is advantageously greatly reduced.
It is preferable in the method according to the invention for not only the hardening substance, but also the infed fluidization medium and the fed-through flushing medium to be supplied through the same fluidization channel in each case. This is advantageous because after the operations have been completed, both the vibrating pipe and the fluidization channel are clean and available for re-use.
The present invention also relates to a vibrating pipe such as that defined in claim 7. The vibrating pipe is suitable in particular for use in the method according to the invention. To this end, the vibrating pipe comprises at least one fluidization channel. The pipe cavity inside the vibrating pipe can be used as the fluidization channel. However, in order to limit pressure losses, the vibrating pipe preferably comprises a fluidization channel on the outside on the lateral surface. In order to prevent the fluidization medium from flowing out of the vibrating pipe through the proximal end, the proximal end of the vibrating pipe is preferably provided with a removable cover as the closing device. During the fluidization, the pipe cavity of the vibrating pipe is closed by the cover. The cover can be removed, for example for placing tension elements.
The fluidization channel of the vibrating pipe can be used for various media. A switching unit is preferably provided in order to make it possible to switch over to the various media, such as water as a fluidization medium, grout as a hardening substance and water again, but then as a flushing medium. The fluidization channel of the vibrating pipe is in flow communication with the switching unit through flexible pipes.
Further preferred embodiments are defined in the remaining subclaims.
The invention will be explained in greater detail with reference to the appended drawings, which give a practical embodiment of the invention, but must not be regarded in a limiting sense, in which drawings:

Fig. 1 is a diagrammatic view of different steps of the method according to the invention;
Fig. 2 shows diagrammatically a view in cross section of a vibrating pipe according to the invention;
Fig. 3A is a view in perspective of the vibrating head of a vibrating pipe according to the invention;
Fig. 3B is a view in perspective of a removable vibrating pipe according to the invention;
Fig. 3C1 is a view in longitudinal section of a vibrating pipe tip without teeth;
Fig. 3C2 is a view in longitudinal section of a removable cover for the vibrating pipe tip, as shown in Fig.3C1; and
Fig. 4 is a view in perspective of the proximal end of a vibrating pipe according to the invention.

Figure 1 is a diagrammatic view of the method according to the invention. Seven successive steps of the method for inserting an anchor block into the ground are shown in Figure 1. The anchor blocks are inserted into the ground 1 in order to anchor an engineering structure 2. The engineering structure here is a construction pit composed of sheet pile walls 3. The construction pit is full of water 4. For the insertion of an anchor block into the ground, a vibrating pipe 10 with a vibrating head 11 is used.
In step 1 of the method the vibrating pipe 10 is placed in position. The vibrating pipe 10 is a hollow steel pipe with a length of at least 15m, in particular at least 25m, and an external diameter of at least 100mm, in particular at least 150mm, and a wall thickness of at least 20mm, but in particular at least 30mm. These dimensions are advantageous for resisting the radial forces which occur when the vibrating pipe is being inserted into the ground. The vibrating pipe is placed in position by means of a crane. The vibrating pipe is connected to a vibrating device 20 at the proximal end. The vibrating device 20 produces vibrations in the axial direction of the vibrating pipe 10.
In the illustrated step 2 of the method according to the invention, the vibrating pipe is positioned relative to the engineering structure 2 to be anchored. For this purpose, a guide element 5 is provided in the engineering structure 2. The distal end of the vibrating pipe is placed in the guide element 5, which is tubular in this case.
In the illustrated step 3 the vibrating pipe has sunk down in the water 4 to the bottom of the construction pit. From this point, a start can be made on inserting the vibrating pipe into the ground by vibrating and fluidizing in the method according to the invention. The fluidizing means that the soil around the vibrating head 11 is mixed with a fluidization medium, such as water, with the result that the soil around the vibrating head starts to behave like a liquid. By fluidizing the soil around the vibrating head 11 and by vibrating, the vibrating pipe will sink further into the ground. When the vibrating pipe has reached the desired depth, the vibrating device 20 is disconnected from the vibrating pipe.
In the illustrated step number 5 in Figure 1 the vibrating pipe is opened at the proximal end. A tension element 6 is passed through the pipe cavity 10a in the vibrating pipe 10 until it reaches the vibrating head. The tension element is, for example, a GEWI bar, possibly with extension pieces, a cable, strands, a reinforcing bar or the like. As can be seen in step 5 of Figure 1, the length of the tension element is such that said tension element extends above the ground surface.
In the illustrated step 6 the vibrating device 20 is again connected to the vibrating pipe 10. In step 6 the vibrating pipe 10 is vibratingly withdrawn from the ground. During the withdrawal from the ground a hardening substance is also introduced through the fluidization channel 12. It is introduced under a pressure of 5 to 25 bar. The hardening substance flows out near the vibrating head and mixes with the soil around the vibrating head, so that there it forms a volume which contributes to the tensioning power of the ultimately obtained anchor block. The tension element 6 is not withdrawn along with the vibrating pipe and is present in the volume of the introduced hardening substance 7. After the introduced hardening substance 7 has hardened, the tension element 6 is immovably connected.
In the illustrated step 7 of Figure 1 the result is shown after the full withdrawal of the vibrating pipe. As illustrated, the volume of introduced hardening substance 7 extends from the bottom to a certain depth below the ground surface. The introduced substance 7 preferably remains at least one metre below the ground surface, but more preferably at least 5m.
The volume of the introduced substance 7, also known as the grout body, does not extend to the ground surface. This is achieved by temporarily stopping with the introduction of hardening substance in the method according to the invention. After the introduction of hardening substance, there is a temporary switch to the introduction of a flushing medium, so that, firstly, the introduced substance 7 does not flow out above the ground surface and, secondly, any residues of introduced substance are flushed out of the vibrating pipe. The temporary stopping of the introduction of hardening substance and the switch to a flushing medium therefore ensures that both the working area and the equipment for placing anchor blocks remain clean.
The engineering structure 2 can be fixed to the tension element 6 projecting above the ground surface in the illustrated step 7 of Figure 1. It has been found that the anchor blocks which are laid as foundation means by the method according to the invention can withstand tensile and/or compressive forces of at least 250 tonnes, which is 2500 kN. The foundation means prevent the engineering structure from sinking or rising. Anchoring is intended in particular to prevent an engineering structure from rising.
Figure 2 is a view in cross section along line II-II, as shown in step number 1 of Figure 1. Four fluidization channels 12 are provided around the vibrating pipe 10 with pipe cavity 10a. The fluidization channels 12 are distributed in a regular pattern over the lateral surface of the vibrating pipe 10. It is preferable for at least two fluidization channels 12, but more preferable for at least four fluidization channels 12, to be provided on the outside of the vibrating pipe 10. The fluidization channels 12 in the method according to the invention can be used for supplying fluidization medium and for introducing hardening substance such as grout. The vibrating pipe 10 here has a length of at least 30m, preferably an external diameter of at least 190mm and a wall thickness of at least 20mm, but more preferably at least 30mm. The fluidization channels preferably have an external diameter of at least 20mm, but more preferably at least 38mm. The wall thickness of the fluidization channels 12 is preferably at least 8mm, but more preferably at least 11 mm. The fluidization channels fixed on the outside of the lateral surface of the vibrating pipe advantageously contribute to the rigidity of the vibrating pipe in the radial direction.
Figure 3A shows in a view in perspective the vibrating head 11 of the vibrating pipe 10. Two fluidization channels 12 are provided on the outside of the vibrating pipe, which fluidization channels are connected by means of connecting flanges 13 to the vibrating head 11. The fluidization channel 12 is in flow communication with the pipe cavity 10a by means of a channel 13a in the connecting flange. A medium fed through the fluidization channel 12 to the vibrating head will leave the vibrating head through the pipe cavity 10a. The vibrating head is furthermore provided with a vibrating pipe tip 14 with teeth 15. The vibrating pipe tip 14 is designed for vibrating the vibrating pipe 10 into the ground. For the sake of clarity, Figure 3A does not show an outflow aperture for the medium fed in through the fluidization channels, which outflow aperture is situated in the pipe cavity 10a at the level of the vibrating pipe.
Figure 3B shows in a view in perspective a removable vibrating pipe tip 14. Depending on the soil conditions, teeth 15 are provided on the circumferential edge on the head end of the vibrating pipe tip 14. If the soil is soft, a vibrating pipe tip 14 without teeth can be used. Furthermore, a convex plate 16 with at least one outflow aperture 17 is provided here inside the vibrating pipe tip 14. An infed medium flows out through the outflow apertures 17, and the medium mixes with the soil around the vibrating pipe tip 14. The number of outflow apertures 17, the distribution over the surface of the convex plate 16 and the direction of the outflow aperture ensure a good distribution of the outflowing medium around the vibrating pipe tip 14.
The vibrating pipe tip 14 can be attached directly or by means of a connecting piece to the vibrating pipe 10. The vibrating pipe tip 14 is designed here with a push-in device 19, which can be pushed into the cavity of the vibrating pipe 10. In order to obtain a seal between the push-in device 19 and the vibrating pipe, a sealing ring, preferably made of rubber, is provided around the outer circumference of the push-in device 19. During the insertion of the vibrating pipe 10 into the ground, the vibrating pipe tip 14 remains connected to the vibrating pipe 10 through the interlocking. When the vibrating pipe is withdrawn, the push-in device 19 will remain behind in the ground. The removal of the vibrating pipe tip 14 is speeded up by vibrating during the withdrawal and by the resting of a tension element on the vibrating pipe tip.
Figure 3C1 in combination with Figure 3C2 shows a simple embodiment of a vibrating head. Figure 3C1 shows a view in longitudinal section of an embodiment of a vibrating pipe tip 114. On one head end a screw thread 115 is provided for connection to the end of a vibrating pipe. The vibrating pipe tip 114 has a pipe cavity 118, such that infed media or a tension element can be fed through the vibrating pipe tip. On the outer circumference of the vibrating pipe tip a groove 116 is also provided. The groove 116 serves for the simple fastening of a cover 110. The cover 110 can be placed over the head end 117 lying opposite the head end of the vibrating pipe tip provided with screw thread 115.
Figure 3C2 shows in a view in longitudinal section the cover 110 belonging to the vibrating pipe tip 114. The vibrating pipe tip 114 together with the cover 110 forms the vibrating head. The cover comprises a plate 111 with a hole 112 as the outflow aperture for infed substance or fluidization medium. The cover furthermore has a vertical wall 113. The wall is thin-walled, such that simply by deformation at the level of the groove the wall can be clamped in the vibrating pipe tip 114. At least part of the wall can be deformed in the direction of the groove 116, in such a way that the cover is fixed in an interlocking manner on the vibrating pipe tip 114. After the vibrating head 114,110 has been inserted to the correct depth in the ground, the cover 110 can simply be removed from the vibrating pipe tip 114 by exerting a force upon the cover with a tension element through the cavity 118. By means of the tension element, the cover can be detached from the vibrating pipe tip. The vibrating pipe can then be withdrawn from the ground, the cover and the tension element remaining behind in the ground. The illustrated cover 110 which remains behind in the ground has the additional advantage that it prevents the tension element from sinking. The cover 110 forms, as it were, an enlarged foot for the tension element. The use of the cover is particularly advantageous in cases where relatively heavy tension elements are used, such as a GEWI steel pile with a length of 20 metres and a diameter of 6cm. Such a heavy tension element can weigh as much as 1000kg, so that the risk of further sinking is considerable. The use of the cover 110 advantageously reduces the risk of sinking.
Figure 4 shows a view in perspective of the proximal end of a vibrating pipe 10. This end of the vibrating pipe is designed for connection to a vibrating device. A fluidization channel 12 is provided along the outside of the vibrating pipe 10, the connection aperture of which fluidization channel is situated near the proximal end of the vibrating pipe. The pipe cavity 10a of the vibrating pipe 10 can be closed by means of a closing device 23. The closing device 23 here is in the form of a cap, which is retained by the vibrating device after placing of the vibrating device. The vibrating device 20 can be connected by means of the welded-on flange plate structure to the vibrating pipe 10. The flange plate structure is made up of four radially extending plates. Every two plates of said structure are connected to each other by a following plate for a connection to the vibrating device.
The vibrating pipe is also provided with a connection 22 for the supply of fluidization medium through the pipe cavity 10a of the vibrating pipe 10.
In addition to the embodiments shown in the figures, many variants are possible without going beyond the scope of protection as set out in the claims. In one variant of the illustrated removable vibrating pipe tip with push-in device, it is also possible, for example, to provide a bayonet closure, a screw thread or a push-on device. Furthermore, in one variant a fluidization channel can be provided in the pipe cavity of a vibrating pipe.
The method according to the invention consequently provides an efficient, quick and money-saving way of inserting anchor blocks into the ground. The risk of damage to surrounding constructions is greatly reduced by the use of the method according to the invention. Furthermore, it is possible by the method according to the invention to keep the working area and the equipment clean.

Claims

Method for inserting into the ground an anchor block for laying a foundation, in particular for anchoring an engineering structure, comprising the following steps:
- positioning a vibrating pipe with a vibrating head on the distal end;

- inserting the vibrating pipe into the ground by means of a vibrating device;
characterized in that the method furthermore comprises the following step:
- while the vibrating pipe is being inserted in the ground, fluidizing the soil around the vibrating head with a fluidization medium, which is fed through a fluidization channel to the vibrating head, the fluidization medium flowing out through a least one outflow aperture in the vibrating head and mixing with the soil around the vibrating head.
Method according to claim 1, in which the vibrating pipe is closed off at the proximal end during the fluidizing.
Method according to claim 1 or 2, in which after the vibrating pipe has been inserted in the ground, the method furthermore comprises the following steps:
- placing a tension element through the vibrating pipe;

- introducing a hardening substance to the vibrating head under pressure, the hardening substance leaving the vibrating pipe near the vibrating head and forming a hardened volume there;

- partially withdrawing the vibrating pipe during the introduction of hardening substance;

- feeding through a flushing medium after the partial withdrawal of the vibrating pipe;

- then fully withdrawing the vibrating pipe.
Method according to claim 3, in which in the method the hardening substance is introduced through the fluidization channel.
Method according to claim 3 or 4, in which the flushing medium is fed through the fluidization channel.
Method according to one of claims 1 - 5, in which the vibrating pipe is withdrawn by vibrating.
Vibrating pipe for inserting an anchor block into the ground for anchoring an engineering structure, characterized in that the vibrating pipe is provided with at least one separate fluidization channel.
Vibrating pipe according to claim 7, in which the fluidization channel is provided on the outside of the vibrating pipe.
Vibrating pipe according to claim 7 or 8, in which the fluidization channel is immovably fixed on the vibrating pipe over at least a part of the length.
Vibrating pipe according to one of claims 7 -9, in which the vibrating pipe comprises a closing device at the proximal end.
Vibrating pipe according to one of claims 7 - 10, in which the vibrating pipe is connected to a switching unit for switching between the infeed of fluidization medium, the introduction of hardening substance and the feeding through of flushing medium.
Vibrating pipe according to one of claims 7 - 11, in which the vibrating pipe is in one piece.