EP3212851B1

EP3212851B1 - Device for cutting piles

Info

Publication number: EP3212851B1
Application number: EP15808784.1A
Authority: EP
Inventors: Martin VAN DROMME; Chris LEHOUCK
Original assignee: DECO Nv
Current assignee: DECO Nv
Priority date: 2014-10-31
Filing date: 2015-11-02
Publication date: 2021-05-19
Anticipated expiration: 2035-11-02
Also published as: EP3212851A1; WO2016067272A1; BE1022222B1

Description

TECHNICAL FIELD

The present invention relates to a cutting device and a method for removing filling material in underwater support posts.
In particular, the invention relates to a device and method for removing filling material in underwater support posts, making use of water jet technology and mechanical pressure.

BACKGROUND

The construction of sea or ocean platforms, e.g. for use as an oil drilling platform, is done by means of anchoring such platforms in the sea bed. To this end, hollow pillars are fixed in the soil, which are then filled with a reinforcing material or filling material. Such material provides the necessary strength and stability of the support structure.
When removing such platforms in marine or aquatic environment, the underwater structures should also be removed. For this purpose, some devices and methods have already been disclosed in the prior art.
For example, WO 2013/019959 describes high power laser systems, tools and methods of using such systems and tools for cutting, sectioning and removing structural objects and materials, particularly in difficult to access environments such as offshore, underwater or hazardous environments such as nuclear or chemical production facilities.
Other techniques require a specific structural construction. WO 2014/080233 relates to offshore structures, such as, for example, structures, that is support piles, for supporting wind turbines. The technology describes an apparatus comprising an acoustic insulation layer between the pile and the surrounding water during the deployment of said pile in the water.
In a similar manner, US 4,372,707 provides a temporary jack-up rig for oil and gas exploration. The rig is brought to the required offshore location and subsequently, support piles are pushed into the sea floor by means of a hydraulic process. Conversely, the piles can again be detached and the structure can be taken to a new location.
US 5,704,732 provides a method for installing and removing deep-water piles, that prevents the need for an underwater hoist. The pile is a hollow tube which is open at the lower end and is provided with a fitting at the upper end. By the injection of air in the piles, water is drawn away and a high external pressure is caused so that the piles are forced into the floor. The clearing of the pile can be accomplished by injecting a high-pressure water jet into the pile through the pile head. The high pressure water jet thereby helps to overcome the external hydrostatic pressure EP-A-2615239 discloses a method according to the preamble of claim 1 and a cutting device according to the preamble of claim 8.
Other techniques make use of water power or mechanical force for breaking materials. However, such techniques do not allow to remove the filling material in such underwater support piles in a quick and efficient manner. Therefore, such structures are cut and removed as such. This does not allow, for example, to partly or completely re-use such underwater structures for other or similar purposes for offshore structures.
The present invention seeks to provide a solution to one or more of the afore-mentioned problems or shortcomings.

SUMMARY

To this aim, the invention provides a cutting device according to claim 8 and a method for clearing underwater support piles according to claim 1.
This offers the advantage that the water jets can cover in a simple manner a large surface area of filling material. Thus, the filling material can be separated from said underwater support piles and then be discharged. This is a quick way to remove filling material from support piles, compared to methods according to the prior art.

DESCRIPTION OF THE FIGURES

The explicit characteristics, advantages and objectives of the present invention will become further apparent to the skilled person in the technical field of the invention after reading the following detailed description of the embodiment of the invention and of the figures enclosed herein. The figures serve the purpose to further illustrate the invention, without thereby limiting the scope of the invention.

Figures 1 to 4 represent a simplified representation of a method and device for hydromechanically removing filling material in a support pile in aquatic environment.
Figure 1 is a schematic representation of a platform 5 at sea 4, wherein the platform 5 is supported on the sea or ocean floor 3 by means of support piles 1.
Figure 2 is a schematic representation of a cutting device 10 for removing filling material 6 in a support pile 1 which is fixed in a seabed 3.
Figure 3A is a schematic perspective view of the underside of a cutting device 10.
Figure 3B also shows a schematic perspective view, wherein one of the water jet elements 15b generates a water jet 23.
Figure 4A-F shows in a schematic manner selected features of spirographic trail 22a-f which can be moved along by the water jet cutting elements 15a, 15b.

DETAILED DESCRIPTION OF THE INVENTION

Unless defined otherwise, all terms used in the description of the invention, including technical and scientific terms, have the meaning as they are commonly understood by the skilled person in the technical field of the invention. For a better assessment of the description of the invention, the following terms are explained explicitly.
"A", "an" and "the" refer in this document to both the singular and the plural, unless the context clearly implies otherwise. For example, "a segment" means one or more than one segment.
When "around" or "about" is used in this document with a measurable quantity, a parameter, a time period or moment in time, and the like, then variations are meant of +/-20% or less, preferably +/-10% or less, more preferably +/-5% or less, even more preferably +/-1% or less, and even more preferably +/-0.1% or less than and of the cited value, to the extent that such variations apply in the described invention. It should, however, be understood that the value of the quantity in which the term "around" or "about" is used, is itself specifically disclosed.
The terms "comprise", "comprising", "consist of", "consisting of", "provided with", "include" "including", "contain", "containing", "encompass", "encompassing" are synonyms and are inclusive or open terms that indicate the presence of what follows, and which do not exclude or prevent the presence of other components, features, elements, members, steps, known from or described in the prior art. Quoting numerical intervals by endpoints comprises all integers, fractions and/or real numbers between the endpoints, these endpoints included.
The invention offers the advantage that the high pressure water jets can process in a simple manner a large surface to of filling material. Thus, the filling material can be detached from its environment and then be discharged. This is a quick way to remove filling material, compared to methods according to the prior art.
The term "underwater support pile" is to be understood as a synonym for the terms "support post", "post", "pillar", "stand", "column", "pile", and indicates preferably a predominantly cylindrical post, which internally comprises a cavity which can be filled with a filling material. Said support pile is or was preferably a part of an underwater structure and acts as an anchoring of said underwater structure in the sea or ocean floor.
The term "underwater structure" is to be understood as a synonym for the term "offshore structure" and indicates any artificial structure which is situated partly or completely under water. Underwater structures which can be cleared advantageous according to the method of the present invention are, for example, but not limited to pipelines of offshore natural gas or oil fields, supporting pillars of offshore drilling platforms and supporting pillars of offshore wind farms.
Figure 1 is a schematic representation of a platform 5 at sea 4, wherein the platform 5 is supported on the sea or ocean floor 3 by means of support piles 1.
The term "filling material" is to be understood as a synonym for the term "grout" or concrete, and indicates a cured mixture of cement, water and optionally one or more aggregates or excipients, or may also be understood as a hard soil or soil types, such as rock, or as soft soil or types of soil, such as clay. In the context of the underwater support piles, grout in flowing state was inserted in a column, where it solidified and thus forms part of a support pile that is reinforced and anchored in the ground. The method and the device according to the present invention may also be applied for removing hard stones types such as, for example, granite or similar natural stone or for soft stone types such as, for example, limestone. Thus, the method and device can also be applied for drilling sockets, tunnels, and the like.
The term "high pressure water jet" should be understood as a water jet having a pressure higher than 50 bar, preferably with a pressure higher than 100 bar, more preferably with a pressure higher than 200 bar and even more preferably with a pressure higher than 300 bar. Most preferably, said water jet has a pressure between 100 bar and 2000 bar.
The term "cutting device with a cutting plane" is to be understood as a synonym for the term "clearing device" and indicates a device provided with one or more cutting means, such as preferably but not limited to, water jet cutting elements, wherein said cutting means are provided in a two-dimensional cutting plane. The term "water jet cutting element" should be understood as a "jet-pipe" or "nozzle" which is suitable to be connected to a water supply pipe and which is provided with a narrowed passage which is intended to increase the pressure of the water jet. Preferably, said cutting device with said cutting plane is provided with 1 to 8 water jet cutting elements, and more preferably 1 to 4 water jet cutting elements. Most preferably, said cutting plane is provided with 2 water jet cutting elements.
Figure 2 is a schematic representation of a cutting device 10 according to the second aspect of the invention, for removing filling material 6 in a support pile 1 which is fixed in a seabed 3. The device 10 is primarily designed cylindrically with an outer diameter which is substantially smaller than the inner diameter of the support pile 1. The bottom surface or cutting plane 12 of the cylindrical device is provided with two nozzles 15a and 15b for the guiding of a water jet 14 and two mechanical crushing elements 12a and 12b for crushing residual filling material 6. In order to keep the device 10 centred in the support pile 1, on the lateral walls of the cylindrical device 10, guiding wheels 17a and 17b are provided. The device 10 is further provided with a suspension 18 for controlling the depth of the device 10 in the support pile 1; and pipes 19 for supplying water 19a and electricity19b, and for discharging pulverized material 19c.
Figure 3A is a schematic perspective view of the underside of a cutting device 10 according to the second aspect of the invention, with indication of two mechanical crushing elements 14a and 14b, two water jet pipes 15a and 15b, two guiding elements 17a and 17b and two discharge pipes 20a and 20b. Figure 3B also shows a schematic perspective view, wherein one of the water jet elements 15b generates a water jet 23.
The term "water jet cutting of filling material" is to be understood as the removing of filling material with the aid of one or more high pressure water jets and indicates the directing of one or more high pressure water jets on said filling material, thereby obtaining that said filling material is partially or entirely pulverized and/or broken down into smaller elements.
The invention offers the advantage that the high pressure water jets can easily cover a large surface area of filling material. Thus, the filling material can be detached from said underwater support piles and then be discharged. This is a quick way to remove filling material from support piles, compared to methods according to the prior art.
Preferably, the predominantly transverse cutting of one or more underwater support piles is carried out by means of a high pressure water jet. This allows to make a cross-section in a simple and relatively safe manner. The use of a high pressure water jet to make the cross-section further ensures a precise cut, so that the finally obtained, detached pillars can be re-used in other applications, whether or not underwater.
In a preferred embodiment, the present invention provides a method according to the first aspect of the invention, wherein during the water jet cutting of the filling material to be removed, an air sleeve or air cushion is provided around said water jet cutting elements. By this is meant that an air cushion is provided around the water jet 23 during the water jet cutting of the filling material 6 to be removed. Such air cushion may be obtained by means of supplying air under increased pressure through the nozzles 16a and 16b. The skilled person will understand that a sufficiently high air pressure will be required for generating an air cushion, and that this pressure is also dependent on the working conditions, such as, for example, the depth below the water surface, and thus also the water pressure, on which said method is carried out.
The present invention provides a method according to the first aspect of the invention, wherein the distance of said water jet cutting elements to the centre of the cutting plane is varied during the water jet cutting.
This offers the advantage that a limited number of waterjet cutting elements can be used while yet the full diameter of the cutting plane is within the range of said water jet cutting elements. Thus, the range of the water jet cutting elements is maximized.
In a preferred embodiment, the present invention provides a method according to the first aspect of the invention, wherein said cutting plane is circular and rotates around the centre of the cutting plane with a rotational speed ω₁.
This offers the advantage that a limited number of waterjet cutting elements can be used while yet the entire circumference of the cutting plane is within the range of said water jet cutting elements. Thus, the range of the water jet cutting elements is maximized. The rotational speed ω₁ may represent both a constant and a variable speed.
The device provides an internal swivel mechanism which is suitable for supplying water through a channel, preferably centrally located in the cutting device, and the subsequent passing of the water through a circular disc 11 via corresponding channels in said circular disk 11. Thus, a circular trail can be travelled. By providing a similar mechanism in the circular disc 11 at the level of the water jet cutting elements 15a and 15b, more complex trails as represented in Figure 4 can be obtained. Such configuration allows to let the one or more water jets cover a spirographic trail 22a-f.
In a preferred embodiment, the present invention provides a method according to the first aspect of the invention, wherein said water jet cutting elements are provided on a circular section, which is located excentrically within said cutting plane and which rotates around its own centre at a rotational speed ω₂. In a further embodiment, two or more circular sections may be provided within said cutting plane.
In a more preferred embodiment, said water jet cutting elements are provided on a circular section with a diameter of less than or equal to half the diameter of afore-mentioned cutting plane, and the centre of said circular section is located halfway between the edge and the centre of afore-mentioned cutting plane. Thus, a relatively simple configuration is provided for the coverage of the entire cutting plane by said one or more water jet cutting elements. Depending on the ratio of the diameters of the cutting plane and afore-mentioned circular section, and of the relative location of the respective centre points of afore-mentioned cutting plane and circular section with respect to one another, another trail will be achieved.
Figure 4A-F shows in a schematic manner selected possibilities of spirographical trails which can be travelled by the water jet devices. Depending on the strength of the filling material, one can opt for an open spirographical trail as in Figure 4A for a filling material with limited strength; or for a dense, closed spirographical trail as in Figure 4F for a filling material with a relatively high strength.
In a preferred embodiment, the present invention provides a method according to the first aspect of the invention, wherein the ratio of the rotational speed ω₂ with respect to the rotational speed ω₁ ranges between 5 and 15.
The skilled person is familiar with the mathematical formulas which provide a relationship between the respective rotational speeds ω₁ and ω₂ of the afore-mentioned cutting plane and circular section on the one hand, and the eventual form of the obtained trail of one or more water jet cutting elements on the other hand. Applying such formulas makes it possible to define an optimal trail according to the nature and structure of the filling material. Preferably, afore-mentioned ratio of the rotational speed ω₂ relative to the rotational speed ω₁ is between 8 and 12, and even more preferably said ratio is equal to 8, 9, 10, 11 or 12, or any value therein between.
Moreover, the skilled person will appreciate that afore-mentioned ratio of the rotational speed ω₂ relative to the rotational speed ω₁ is decisive for the trail or the path which is travelled by one or more water jet cutting elements. The choice of the ratio may therefore also be determined by the desired trail, wherein the desired trail is determined according to the nature of the filling material.
In a preferred embodiment, the present invention provides a method according to the first aspect of the invention, wherein said water jet cutting elements are provided with water supply at a pressure between 1 bar and 10 bar and a flow rate of between 100,000 and 1,000,000 litres per hour. Preferably, said water jet cutting elements are provided with water supply at a pressure of between 4 bar and 10 bar, and more preferably between 6 bar and 10 bar. Most preferably, said water jet cutting elements are provided with water supply at a pressure of 7 bar, 8 bar, 9 bar, or any pressure therein between. Preferably, said water jet cutting elements are provided with water supply at a flow rate between 200,000 and 800,000 litres per hour, and more preferably between 200,000 and 600,000 litres per hour. Most preferably, said water jet cutting elements are provided with water supply at a flow rate of 300,000, 400,000, 500,000 litres per hour, or any flow rate therein between.
In a preferred embodiment, the present invention provides a method according to the first aspect of the invention, wherein the pulverized filling material is temporary held in suspension before being discharged. By this is meant that process water is supplied through the supply pipes 21a and 21b for holding the pulverized filling material in suspension. This offers the advantage that the pulverized filling material can be discharged easily. Preferably, said process water is supplied at a pressure of 2 bar to 25 bar, more preferably of 4 bar to 16 bar and even more preferably of 6 bar to 12 bar. Most preferably, said process water is supplied at a pressure of 7 bar, 8 bar, 9 bar, 10 bar, 11 bar, or any pressure therein between.
In a preferred embodiment, the present invention provides a method according to the first aspect of the invention, wherein said cutting plane is provided with one or more mechanical crushing elements which are shifted within said cutting plane during the water jet cutting.
Such mechanical crushing elements offer the advantage that the non-crushed filling material, which is untouched by the water jets yet is structurally weakened, can be crushed anyway by means of a light or limited mechanical pressure exerted by said crushing elements.
In a second aspect, the present invention provides a cutting device according to claim 8.
This offers the advantage that said water jet cutting elements can be translocated within the area of the cutting plane. Thus, the need for the number of water jet cutting elements can be limited, because some water jet cutting elements can exert an impact on a relatively large surface area.
In a preferred embodiment, the present invention provides a cutting device according to the second aspect of the invention, wherein said water jet cutting elements are provided on a circular section, which is arranged rotatably and excentrically within said cutting plane. In a further embodiment, two or more circular sections may be provided in the afore-mentioned manner within said cutting plane. In a more preferred embodiment, said water jet cutting elements are provided on a circular section with a diameter smaller than or equal to half the diameter of said cutting plane, and the centre of said circular section is located halfway between the edge and the centre of afore-mentioned cutting plane.
In a preferred embodiment, the present invention provides a cutting device according to the second aspect of the invention, wherein positioning elements are provided laterally of said cutting plane for centring said cutting device within said support pile.
In a more preferred embodiment, said positioning elements are comprised of two or more rolling elements, for example wheels, in which the rolling direction of said rolling elements corresponds to the direction in which said filling material is removed. Preferably, said cutting device comprises 3 or 4 positioning elements. More preferably, said positioning elements are arranged radially spread along the circumference of the cylindrical cutting device.
In a preferred embodiment, the present invention provides a cutting device according to the second aspect of the invention, wherein one or more air supply channels are provided for providing an air sleeve around said water jet cutting elements. By this is meant that the air supply channels 16a and 16b supply air under a high pressure, and thereby surround the water jets 23, which are generated by the water jet cutting elements 15a and 15b, with an air sleeve.
In a preferred embodiment, the present invention provides a cutting device according to the second aspect of the invention, wherein said cutting plane is provided with one or more supply pipes for supplying process water. By this is meant that is provided with supply pipes 21a and 21b for process water for holding the pulverized filling material in suspension. This offers the advantage that the pulverized filling material can easily be discharged.
In a preferred embodiment, the present invention provides a cutting device according to the second aspect of the invention, wherein said cutting plane is provided with discharge pipes for evacuating cut and/or crushed filling material.
Such transport ensures that no local build-up of the filling material occurs. Preferably, said transport is achieved by means of an air lift. Such an air lift allows an operationally easy transport of the pulverized filling material.
In a preferred embodiment, the present invention provides a cutting device according to the second aspect of the invention, in which the end facing away from the cutting plane of the cutting device is provided with means for suspending said cutting device.
In a preferred embodiment, the present invention provides a cutting device according to the second aspect of the invention, wherein said cutting plane is provided with mechanical crushing elements.
Preferably, such crushing elements are comprised of a roller having a central axis, which axis is arranged at least partially recessed in the cutting plane and which axis is directed from the edge of the cutting plane to the centre of the cutting plane. Thus, the rotation with rotational speed ω₁ allows that the crushing elements can be shifted along the entire circumference of the cutting plane with a rotational speed ω₁. Preferably, one or more crushing elements are provided at different distances to the centre point of the cutting plane. Preferably, said cutting device with cutting plane is provided with 1 to 8 mechanical crushing elements, and more preferably 1 to 4 mechanical breaking elements. Most preferably, said cutting plane is provided with 2 mechanical breaking elements.
In a preferred embodiment, the present invention provides a cutting device according to the second aspect of the invention, wherein said mechanical elements are comprised of rollers with one or more cutting edges.
Such cutting edges are to be understood as one or more upright edges along the circumference of said rollers. Such upright edges provide a smaller contact surface between the mechanical crushing elements and the filling material to be pulverized. As a result, the applied pressure of the mechanical crushing elements on the filling material to be pulverized is proportionally increased, thereby obtaining a better pulverizing effect.
In a third aspect, the present invention provides a use of a cutting device according to the second aspect of the invention, for clearing underwater support piles, wherein said support piles are comprised of a cylindrical wall comprising a filling material.

Claims

Method for clearing underwater support piles (1), wherein said support piles (1) are comprised of a wall comprising a filling material (6), comprising the steps of:
i. predominantly transverse cutting of one or more underwater support piles (1), thereby obtaining an open cross-section,

ii. providing a cutting device (10) with a cutting plane (12) opposite to said open cross-section, wherein said cutting plane (12) is provided with one or more water jet cutting elements (15a, 15b), and

iii. water jet cutting of said filling material (6) whereby said water jet cutting elements (15a, 15b) are shifted within said cutting plane (12),
characterized in that the distance of said water jet cutting elements (15a, 15b) to the centre of the cutting plane (12) is varied during the water jet cutting.
Method according to claims 1 or 2, wherein said cutting plane (12) is circular and rotates around the centre of the cutting plane (12) with a rotational speed ω₁.
Method according to at least one of the preceding claims 1 to 3, wherein said water jet cutting elements (15a, 15b) are provided on a circular section (13), which is located excentrically within said cutting plane (12) and which rotates around its centre with a rotational speed ω₂.
Method according to claim 2 and 3, wherein the ratio of the rotational speed ω₂ relative to the rotational speed ω₁ is between 5 and 15.
Method according to at least one of the preceding claims 1 to 4, wherein an air sleeve is provided around said water jet cutting elements (15a, 15b) during the water jet cutting.
Method according to at least one of the preceding claims 1 to 5, wherein said cutting plane (12) is provided with one or more mechanical crushing elements (14a, 14b) which are shifted within said cutting plane (12) during the water jet cutting.
Method according to at least one of the preceding claims 1 to 6, wherein the pulverized filling material is temporary held in suspension before being discharged.
Cutting device (10) for clearing underwater support piles (1), wherein said support piles (1) are comprised of a cylindrical wall comprising a filling material (6), said cutting device (10) comprising a cutting plane (12) provided with one or more water jet cutting elements (15a , 15b), wherein said water jet cutting elements (15a, 15b) are movable in position within said cutting plane (12),
characterized in that the distance of said water jet cutting elements (15a, 15b) to the centre of the cutting plane (12) is variable.
Cutting device (10) according to claim 8, wherein said water jet cutting elements (15a, 15b) are provided on a circular section (13), which is arranged rotatably and excentrically within said cutting plane (12).
Cutting device (10) according to claim 8 or 9, wherein positioning elements (17a, 17b) are provided laterally of said cutting plane (12) for centring said cutting device (10) within said support pile.
Cutting device (10) according to at least one of the preceding claims 8 to 10, wherein one or more air supply channels (16a, 16b) are provided for providing an air sleeve around said water jet cutting elements (15a, 15b).
Cutting device (10) according to at least one of the preceding claims 8 to 11, wherein said cutting plane (12) is provided with mechanical crushing elements (14a, 14b).
Use of a cutting device (10) according to at least one of claims 8 to 12 for clearing underwater support piles (1), wherein said support piles (1) are comprised of a cylindrical wall comprising a filling material (6).