EP4335974A1 - Method of inserting a profile into the ground and vibrator assembly therefor - Google Patents

Abstract

The invention relates to a method for introducing a profile into the subsoil, in particular for offshore applications, by means of a vibrator (20) guided on a rope (6) and resting on the profile (1) to be introduced, characterized in that by means of a ballast container (5) a variable weight force is applied to the vibrator (20). The invention further relates to a vibrator arrangement (2) for carrying out the method according to one of the preceding claims for introducing a profile (1) into the subsoil, in particular for offshore applications, with a vibrator (20) guided on a rope (6). rests on the profile (1) to be introduced, characterized in that a ballast container (5) is provided with a supply or drain line, which applies a variable weight force to the profile (1) by supplying or draining a fluid into the ballast container (5). /or the vibrator (20).

Description

The invention relates to a method for introducing a profile into the subsoil, in particular for offshore applications, by means of a vibrator guided on a rope which rests on the profile to be introduced. The invention further relates to a vibrator arrangement for this.

Various methods for introducing profiles into the subsoil (soil) are known in the prior art. The different methods are suitable for different profiles, profile sizes and substrates depending on the final depth to be achieved. The profiles are mostly semi-finished products made of steel as long products that are manufactured in a defined shape and whose cross-section is the same over its entire length. Steel profiles are rolled, drawn or pressed and are, for example, sheet piles, steel beams, pipes or the like. Such profiles can be pressed, vibrated or hammered into the ground using appropriate insertion devices.

Pressing a profile into the ground by applying sufficient weight to the profile is a very gentle insertion process that, for example, does not lead to vibrations into the body of water (hydrosound), even offshore. However, for most applications, the required final depth for the profile to be inserted is far from being achieved. For example, in the DE 2 312 727 A1 a method and device for pressing a component into the ground is described, in which the weight force to be exerted on the component to be pressed can be increased by filling separate tanks with seawater. Nevertheless, the static load of weights and thus the successful bringing down is important of profiles desired for insertion, limited to soft or easily penetrable soils and/or smaller profile cross sections.

Furthermore, piling devices are known which insert a profile to be introduced into the subsoil using ramming blows. Both free-riding piling devices are known, which are placed on the profile and are not actively guided, as well as piling devices that are arranged on a so-called leader as a guide device, usually attached to a construction machine, and precisely guide the profile to be inserted into the ground. The piling device can also use the leader to load part of its weight onto the profile to be inserted, so that improved propulsion is achieved during the respective piling strokes. However, in offshore applications, leaders cannot be used without great effort. Another general disadvantage of pile driving devices is the considerable noise that is triggered by the ramming blows and, when used in water, is also transmitted to the body of water and causes a significant impairment of nature in the sea.

For ever larger profiles, especially in the area of offshore applications, i.e. the introduction of profiles to the seabed, for example for the foundation of drilling rigs or wind turbines, ever larger profiles are introduced into the seabed. For wind turbines, for example, so-called monopiles, i.e. a simple but large steel pipe, are used as a foundation in the seabed. Such monopiles currently have diameters of over 5 meters, in particular 6 meters, up to 10 meters and a pipe wall thickness of 30 to 80 mm. It can be assumed that even larger monopiles will be used in the future. Accordingly, it is necessary to distribute the impact energy generated by ramming over a large radius and thus over a large area. Anvil weights placed on the monopile to distribute the impact energy are known for this purpose.

Furthermore, from the WO 2020/263095 A1 The so-called "BLUE PILING Technology" (trademark of IHC Holland IE BV) is known, in which a large mass of seawater stored in a container is lifted and dropped for ramming. Although the slightly longer impact impulse, i.e. the changed impact characteristics, is intended to enable a reduction in underwater noise compared to conventional hammer blows, extremely powerful ramming blows are nevertheless required to insert the large monopiles, which continue to have a significant impact on the environment, in particular on hydrosound emissions , condition.

Furthermore, as already mentioned at the beginning, vibration introduction methods are known. On land, similar vibrators to the pile driving devices are known, which, for example, are placed on the profile to be inserted as a free-riding, so-called vibrator bear and are not actively guided. Alternatively, vibrators are known that are precisely guided on the aforementioned leaders. Compared to the pile driving process, the impact on the environment caused by inserting the profiles with vibrators is significantly lower. Accordingly, the vibration methods can often be used in built-up areas where conventional pile driving would lead to significant structural damage. Accordingly, when used in the sea, i.e. when vibrations/shocks are transmitted into the body of water during vibration, lower hydrosound emissions are likely to occur compared to ramming.

Despite these advantages, vibration technology is not or rarely used in the marine sector and in particular for larger profiles, since, for example, large profiles such as monopiles with diameters of over 5 meters are not inserted to the final depth even in medium-dense sand, such as that found in the North Sea can be. If you want to use the gentler vibration technology, you have to switch to ramming when the vibration process reaches a maximum depth, which is time-consuming and costly.

The object of the invention is therefore to improve the vibration technology for inserting large profiles, especially in offshore applications, in order to be able to insert the profile to be inserted to the final depth by means of vibration.

This problem is solved with a method according to claim 1 and/or a vibrator arrangement according to claim 8.

If a variable weight force is applied to the vibrator using a ballast container, the load on the vibrator can be brought to the required level during the insertion process in order to be able to insert the profile to be inserted to the final depth.

The variable weight force is preferably achieved by pumping or draining water into or out of the ballast container. Particularly for offshore applications, pumping of seawater into the ballast container and/or draining of seawater from the ballast container as required is provided. Of course, this application is also possible on land, provided that a correspondingly large water reservoir, for example a lake or a river or an artificial water reservoir, is available.

Because the variable weight of the ballast container is vibration-decoupled from the vibrator, the weight of the ballast container alone acts as a quasi-static load, so that the mass inertia of the load is not activated.

If the vibrator and ballast container (and the profile to be inserted underneath) are caused to vibrate by the vibrator so that the additional load increases the vibrating mass, the rope must alternatively be vibration-decoupled from the ballast container and vibrator. This prevents these vibrations from being transmitted to the tether of the arrangement. Otherwise, the retaining rope and thus also the crane holding the vibration device could be caused to vibrate uncontrollably.

Because the propulsion speed is measured when introducing the profile and the variable weight force is increased when the propulsion speed is reduced and reduced when the propulsion speed is increased, a controlled, controlled insertion process can be carried out, which regulates the variable weight force in accordance with the propulsion speed.

Additionally or alternatively, the load can be regulated using appropriate hydrosound measurements so that specified hydrosound limit values are adhered to, namely by measuring the hydrosound emission when the profile is inserted and the variable weight force is increased with reduced hydrosound emissions and reduced with increased hydrosound emissions.

If, after reaching the final depth, the vibrator is switched off and the variable weight force is increased to the maximum weight, the profile to be introduced is, in a quasi-static manner, braced or brought into force with the ground by the maximum load, since when vibrating, the profile changes according to the dynamic after the vibration process has been completed The laws are slightly regressed, so there would not yet be a direct adhesion between the profile end face and the ground.

According to the device, the object is achieved in that a ballast container is provided with a supply or drain line, which exerts a variable weight force on the profile and / or the vibrator by supplying or draining a fluid into the ballast container. In the case of offshore applications, the fluid is seawater. The seawater is supplied, for example, via a submersible pump.

If the vibrator is arranged above the ballast container on the profile, with the rope attached to the vibrator via a second vibration isolator, the ballast container and the vibrator together form the vibrating mass, so that the rope attached to it must then be positioned so that it is decoupled from vibrations.

In an alternative embodiment, the ballast container is arranged above the vibrator on the profile, with the rope also being attached to the ballast container via a second vibration isolator. Here too, the ballast container and vibrator form a jointly vibrating mass.

In order not to activate the mass inertia of the ballast container, the vibrator sits directly on the profile and the ballast container is loaded onto the vibrator via a first vibration isolator, with which the vibrator transmits its vibrations directly to the profile to be introduced, but through the intermediate first vibration isolator between the vibrator and ballast container does not transmit the vibrations to the ballast container.

If sensors for determining the propulsion speed are arranged on the vibrator and/or on the ballast container, which interact with a detection and control device, the corresponding control can be carried out during the insertion process and the insertion process can be recorded.

Furthermore, hydrosound sensors are preferably arranged for measuring the hydrosound in the surrounding body of water, which are operatively connected to the detection and control device, so that compliance with nature conservation regulations can be checked and recorded.

In order to be able to provide a correspondingly suitable, sufficiently variable load, the ballast container has a tank volume for water of 5 to 50 cbm, in particular 10 to 20 cbm. This means that when filling with water/seawater, 5 to 50 tons or preferably 10 to 20 tons of additional load can be filled in or drained off again if necessary.

The profile to be introduced is preferably a monopile with a diameter greater than 5 m.

Two exemplary embodiments of the invention and the bringing down process are described in detail below using the following drawings.

Fig. 1

eine Vibratoranordnung in einem ersten Ausführungsbeispiel in schematischer, teils geschnittener Seitenansicht,

Fig. 2

in zur Fig. 1 ähnlicher Darstellung eine Ausführung einer Vibratoranordnung in einem zweiten Ausführungsbeispiel und

Fig. 3

eine grafische Darstellung eines beispielhaften Einbringvorganges.

It shows:

Fig. 1

a vibrator arrangement in a first exemplary embodiment in a schematic, partly sectioned side view,

Fig. 2

in to Fig. 1 Similar representation of an embodiment of a vibrator arrangement in a second exemplary embodiment and

Fig. 3

a graphic representation of an exemplary insertion process.

In Fig. 1 A vibrator arrangement in a first exemplary embodiment is shown in a schematic, partly sectioned side view. There, a profile 1 to be introduced, for example a monopile, is shown in a substantially vertical orientation, already partially inserted into a seabed B, over which a body of water W, for example the sea in the offshore area, extends. The profile has an elongated shape, with the cross section being the same over its entire length. The profile 1, here a monopile, has a profile base 12, which is to be inserted into the ground to a final depth T. The upper end of the profile 1, the profile head 11, is then later used to fasten the structure to be built, for example a wind turbine or the like. To insert the profile 1 into the ground B, a vibrator arrangement 2 is seated on the profile head 11, consisting of a vibrator 20, a vibration isolator 3 and a ballast container 5. The vibrator arrangement 2 is lifted, handled and guided by a crane or the like via a rope 6 in order to be able to place and hold the vibrator arrangement 2 on the profile head 11 of the profile 1 to be inserted.

The first vibrator arrangement 2 'in a first embodiment according to Fig. 1 is characterized by the fact that it rides on the profile head 11 of the profile 1 Vibrator 20 is assembled via a first vibration isolator 31 with the ballast container 5 arranged above it.

In contrast, the in Fig. 2 illustrated second embodiment as a second vibrator arrangement 2 "according to Fig. 2 constructed from the vibrator 20, which rides directly on the profile head 11 of the profile 1 to be introduced and has a directly attached ballast container 5 with a second vibration isolator 32 arranged above it.

Each at the upper end of the vibrator arrangement 2, according to Fig. 1 thus at the upper end of the ballast container 5 and in Fig. 2 The rope 6 for handling the entire device is attached to the upper end of the second vibration isolator 32. The crane required for handling, on which the rope 6 is guided and raised if necessary, is shown in the figure for the sake of clarity Fig.1 and 2 not shown.

The vibrator 20 provided in the first or second vibrator arrangement 2'/2" is a vibrator that is basically known in the prior art, the unbalance amplitude and frequency of which can be changed in the usual way. The vibrator 20 of course has a certain weight with which this vibrator 20 sits on the profile head 11 of the profile 1 to be inserted. For this purpose, a connecting element 21 is formed on the vibrator 20, which rests as precisely as possible on the profile head 11 of the profile 1 to be inserted and also guides the vibrator arrangement 2 sitting on the profile 1.

In execution according to Fig. 1 The first vibrator arrangement 2 'has a first vibration isolator 31 above the vibrator 20, which neutralizes the vibrations generated by the vibrator 20 and essentially does not transmit them to the ballast container 5 sitting above the first vibration isolator 31. Such vibration isolators are known in the prior art.

The ballast container 5 encloses a cavity 50, to which a supply line 51 with a pump 52 is connected, with which water, in particular seawater, can be pumped into the cavity 50 of the ballast container 5 by means of the pump 52 via the supply line 51, which extends into the water body W. Furthermore, a drain line 53 is connected to a drain valve 54 so that water can be drained into the water body W via the drain line 53 by opening the drain valve 54.

Furthermore, a detection and control device 7 is provided, which is operatively connected to the vibrator 20, the pump 52 and the drain valve 54. Furthermore, in the illustrated embodiment according to Fig. 1 a hydrophone 8 arranged in the water body W is operatively connected to the detection and control device 7, which can measure the hydrosound in the water body W.

Alternative to the embodiment according to Fig. 1 is in Fig. 2 in the second vibrator arrangement 2", the ballast container 5 is arranged directly on the vibrator 20, so that the separate load on the ballast container 5 increases the oscillating mass of the vibrator 20. So that the rope 6, on which the second vibrator arrangement 2" is secured and handled, no Vibrations can be transmitted undesirably to the crane carrying the rope 6, the second vibration isolator 32 is provided above the ballast container 5.

By designing the ballast container 5 with the cavity 50 provided therein, the weight of the ballast container 5 and thus the load on the profile 1 to be introduced can be varied by supplying water (sea water) into the cavity 50. By pumping water into the cavity 50, the surcharge is increased and by draining water from the cavity 50, the surcharge is reduced.

In an exemplary insertion process, which is in Fig. 3 in two graphs, one the regulated load over time and one the depth reached over time is listed. When the profile 1 to be introduced is placed on the seabed B, a first static minimal indentation is already achieved due to the weight of the profile 1 and the vibrator 20 placed thereon. The dynamic insertion process then begins by activating the vibrator 20 with a low load. If necessary, the entire vibrator arrangement 2 is relieved by the crane via the rope 6 and is only subjected to a very small load on the profile head 11 of the profile 1 to be inserted. As the profile 1 progressively vibrates into the seabed B, the load increases according to the upper curve Fig. 3 increased by pumping seawater into the cavity 50 of the ballast container 5, whereby a suitable propulsion speed, i.e. further penetration of the profile base 12 of the profile 1 into the seabed B, is achieved.

If the profile base 12 of the profile 1 to be inserted reaches a softer or more easily penetrable layer in the subsurface, the load weight of the ballast container 5 can be reduced or not increased further by appropriate regulation via the detection and control device 7 in order to continue to ensure that the insertion process is as uniform as possible to ensure a constant rate of advance. This situation gives the in Fig. 3 _" Dent" shown in the upper graph in the area marked with an arrow. With further propulsion, the load is then increased again and ended when the desired final depth T is reached. This turns off the vibrator 20.

In a preferred embodiment of the introduction method, however, the load is not immediately reduced and lifted, but rather the cavity 50 is first filled to the maximum with seawater via supply line 51 and pump 52 in order to achieve static repositioning of the introduced profile 1. The profile 1, which springs back slightly when the vibration process ends, is pressed into the seabed B by the increased static load at least to such an extent that the profile base 12 of the introduced profile 1 enters into a frictional connection or in a state of tension with the seabed B. This is particularly useful for large profiles 1, for example monopiles with a diameter greater than or equal to 5 m and a material thickness of the monopile of, for example, up to 80 mm, in order to immediately reduce the peak resistance without further settlement movements when the profile 1 is used further, for example as a foundation for a wind turbine to be able to use. After this static settling process, the load is then reduced by draining the water from the cavity 50 of the ballast container 5 and finally the entire vibrator arrangement 2 is lifted off by a crane using the rope 6.

For comparison with a vibration introduction process without a separate ballast container 5, i.e. without a variable weight force, associated dashed graphs are shown, from which it can also be seen that in the case of medium-dense sand in the seabed B, as is the case in the North Sea, for example, the desired final depth T is not reached can be.

Due to the variable weight force to be applied to the vibrator 20 by means of the ballast container 5, the propulsion speed when inserting the profile 1 can be adjusted not only by changing the vibrator frequency and possibly the unbalance amplitude of the vibrator, as is already known from the prior art, but by a Conscious control, i.e. changing the weight load, can be achieved by means of a ballast container 5, into the cavity 50 of which water is pumped in or drained if necessary. It is advantageous if the propulsion speed is measured when the profile is introduced and, when the propulsion speed is reduced, the load is increased by pumping water into the cavity 50 and when the propulsion speed increases, the load on the ballast container 5 is reduced by draining water from the cavity 50. Through this control loop, the insertion process is evened out and a significantly greater insertion depth of the profile is achieved overall.

Likewise, by additionally measuring the hydrosound emission using the hydrophone 8, the load can be determined depending on the measured hydrosound to be changed. In parallel to the first-mentioned control circuit, a maximum permissible hydrosound emission can be specified in the detection and control device, whereby when this hydrosound emission limit is reached, the load is reduced by draining water from the cavity 50 of the ballast container 5 and, as a result, the hydrosound emission is also reduced. Depending on the other control parameters, the load weight can then be increased by pumping water into the cavity 50 of the ballast container 5 with correspondingly low hydrosound emissions and thus the propulsion speed can be increased again when the profile 1 is introduced.

Reference symbol list

1

Profile, monopile

11

Profile header

12

Profile foot

2, 2', 2"

Vibrator arrangement

20

vibrator

21

Connection part

3

Vibration isolator

31

first vibration isolator

32

second vibration isolator

4

Rope

5

Ballast container

50

cavity

51

Supply line

52

pump

53

Drain line

54

drain valve

6

Rope

7

Acquisition and control device

8th

Hydrophone, hydrosonic sensor

b

ground, seabed

W

water body

T

final depth

Claims (15)

Method for introducing a profile into the subsoil, in particular for offshore applications, by means of a vibrator (20) guided on a rope (6) and resting on the profile (1) to be introduced, characterized in that by means of a ballast container (5). variable weight force is applied to the vibrator (20). Method according to claim 1, characterized in that the variable weight force is achieved by pumping or draining water into or out of the ballast container (5). Method according to claim 1 or 2, characterized in that the variable weight of the ballast container (5) is vibration-decoupled from the vibrator (20). Method according to claim 1 or 2, characterized in that the rope is vibration-decoupled from the ballast container (5) and vibrator (20). Method according to one of the preceding claims, characterized in that the propulsion speed is measured when the profile (1) is introduced and the variable weight force is increased at a reduced propulsion speed and reduced at an increased propulsion speed. Method according to one of the preceding claims, characterized in that the hydrosound emission is measured when the profile (1) is introduced and the variable weight force is increased when the hydrosound emission is reduced and is reduced when the hydrosound emission is increased. Method according to one of the preceding claims, characterized in that after reaching the final depth (T), the vibrator (20) is switched off and the variable weight force is increased to maximum weight. Vibrator arrangement (2) for carrying out the method according to one of the preceding claims for introducing a profile (1) into the subsoil, in particular for offshore applications, with a vibrator (20) guided on a rope (6) which is mounted on the profile to be introduced (2) 1), characterized in that a ballast container (5) is provided with a supply or drain line, which applies a variable weight force to the profile (1) and/or the vibrator (by supplying or draining a fluid into the ballast container (5). 20) exercises. Vibrator arrangement (2) according to claim 8, characterized in that the vibrator (20) is arranged above the ballast container (5) on the profile (1), the rope (6) being attached to the vibrator (20) via a second vibration isolator (32). is attached. Vibrator arrangement (2) according to claim 8, characterized in that the ballast container (5) is arranged above the vibrator (20) on the profile (1), the rope (6) being attached to the ballast container (5) via a second vibration isolator (32). is attached. Vibrator arrangement (2) according to claim 8 or 10, characterized in that the vibrator (20) sits directly on the profile (1) and the ballast container (5) is loaded onto the vibrator (20) via a first vibration isolator (31). Vibrator arrangement (2) according to one of claims 8 to 11, characterized in that sensors for determining the propulsion speed on the vibrator (20) and / or on Ballast containers (5) are arranged, which interact with a detection and control device (7). Vibrator arrangement (2) according to one of claims 8 to 11 with claim 12, characterized in that hydrosonic sensors (8) are arranged for measuring the hydrosound in the surrounding body of water (W), which are operatively connected to the detection and control device (7). Vibrator arrangement (2) according to one of claims 8 to 13, characterized in that the ballast container (5) has a tank volume for water of 5 to 50 cbm, in particular 10 to 20 cbm. Vibrator arrangement (2) according to one of claims 8 to 14, characterized in that the profile (1) to be introduced is a monopile with a diameter greater than 5 m.

Images