GB2609452A

GB2609452A - An underwater structure construction method

Info

Publication number: GB2609452A
Application number: GB2111056.4A
Authority: GB
Inventors: Bin Sulayem Sultan; Carlos Juan; Bostock Harvey
Original assignee: Dp World Fze
Current assignee: Dp World Fze
Priority date: 2021-07-30
Filing date: 2021-07-30
Publication date: 2023-02-08
Anticipated expiration: 2041-07-30
Also published as: GB2609452B; WO2023007124A1; GB202111056D0

Abstract

A construction method for an underwater structure, e.g. a breakwater, using a plurality of structure containers 7-10, each at least partly permeable to liquid, at least partly filled with a dry concrete composition (16, Fig. 5) and each having flexible side walls 11, the method including positioning a lower layer 17 of containers on a base surface 18 such that adjacent side walls are in contact, positioning an upper layer 19 on top of the lower layer, which provides a downward force to the lower layer such that the containers’ side walls are biased towards each other, maintaining contact with one another, submerging the layers of containers so that water permeates into them, and allowing the hydrated composition to set to form a rigid structure. The container may be biodegradable bags or sacks of permeable material, and may be filled on site with cement, sand and aggregate, and may include lifting handles. The base surface may be a seabed, or, if unlevel, may be created by gravel sacks which are ruptured so that gravel coalesces forming a foundation layer.

Description

An underwater structure construction method

FIELD

The present invention relates to an underwater structure construction method and more particularly to a method of constructing a breakwater.

BACKGROUND

A conventional method for constructing an underwater structure, such as a breakwater, typically involves piling up rocks or prefabricated concrete shapes to form a wall. In some instance, the rocks or concrete shapes are covered with cement to form a platform.

The problem with conventional construction methods is that heavy equipment is required to transport and position the rocks or prefabricated concrete shapes. Prefabricated concrete shapes can also be complex and expensive to manufacture. Furthermore, prefabricated concrete shapes are typically manufactured offsite and transported for installation. Transporting such large and heavy items is difficult and costly, both in terms of the energy required and the financial expense.

Further conventional methods for constructing underwater structures involve drilling holes in the seabed and installing pylons upon which a fixed or floating walkway can be constructed. However, once again such conventional methods require heavy machinery and components must be manufactured at a remote location and transported to the installation site.

There is a need for an improved underwater structure construction method which alleviates at least some of the problems outlined herein.

SUMMARY

The present invention provides a method as claimed in claim 1 and a breakwater as claimed in claim 16. The present invention also provides preferred 5 embodiments as claimed in the dependent claims.

The underwater structure construction method of some examples of this disclosure enables an underwater structure to be constructed more easily than conventional methods because the method avoids the need for heavy machinery.

The method of some examples of this disclosure uses readily available materials which may be transported easily. In some examples, the method avoids the need for offsite assembly.

The method of some examples of this disclosure provides a simple and effective way to level an uneven or sloping seabed to provide a foundation for an underwater structure.

The method of some examples of this disclosure is environmentally beneficial compared with conventional construction methods because the method avoids the need for heavy machinery which can be polluting and which requires significant energy to operate. Heavy machinery can also damage wildlife habitats, either on land or in the water.

BRIEF DESCRIPTION OF THE FIGURES

In order that the present disclosure may be more readily understood, preferable embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of an underwater structure carrying a walkway of some examples of this disclosure; Figure 2 is a cross-sectional view of an underwater structure of an example of this disclosure; Figure 3 is a further cross-sectional view of the underwater structure of figure 2; Figure 4 is a plan view of part of the underwater structure of figure 2; Figure 5 is a diagrammatic side view of part of an underwater structure of this

disclosure;

Figure 6 is a further diagrammatic side view of an underwater structure of this disclosure; Figure 7 is a diagrammatic side view of part of a foundation of an underwater

structure of this disclosure;

Figure 8 is a further diagrammatic side view of the foundation of figure 7; Figure 9 is a diagrammatic side view of a further underwater structure of this disclosure; and Figure 10 is a further diagrammatic side view of the underwater structure of figure 15 9.

DETAILED DESCRIPTION OF THE DISCLOSURE

Referring initially to figure 1 of the accompanying drawings, an underwater structure of one example of this disclosure takes the form of a breakwater 1. In this example, the breakwater 1 is an island breakwater which extends from a beach out into the sea. In this example, a walkway 2 is mounted to the breakwater 1 using a plurality of elongate walkway supports 3 such that the walkway 2 is supported in a spaced apart position relative to the breakwater 1. The walkway 2 thus provides a raised platform which extends out to sea for use as a viewing platform or to enable users to broad or disembark a boat. It is, however, to be appreciated that the walkway 2 is optional and is omitted in other example underwater structures of this disclosure.

Referring now to figures 2-4 of the accompanying drawings, the walkway 1 comprises a plurality of structure containers 4 which are stacked on top of one another. The structure containers 4 are layered, with the width of the layers decreasing from bottom to top such that the breakwater 1 has a generally pyramid-shaped cross-section, as shown in figure 3. In other examples, the breakwater or other underwater structure comprises a different number of structure containers 4 to the number shown in figures 2-4. In other examples, the number of structure containers is selected to provide sufficient layers of the pyramid structure for the upper level of the structures to be at an appropriate height, such as at or close to sea level.

The stack of structure containers 4 is positioned on a base surface, which may be seabed 5 if the seabed 5 is suitably level. Alternatively, the base surface may be 10 an upper surface of a foundation layer 6 which sits on top of the seabed 5 and which provides a level base surface to carry the structure containers 4.

An underwater structure construction method of some examples of this disclosure will now be described with reference to figures 5 and 6.

The method comprises providing a plurality of structure containers 7-10. It is to be appreciated that only four structure containers 7-10 are shown in figures 5 and 6 but in practice there may be any number of structure containers used to construct an underwater structure.

In this example, the structure containers 7-10 are identical or substantially identical to one another. For simplicity, only the first structure container 7 will be described below, but it is to be appreciated that the other structure containers 8-10 are identical or substantially identical to the first structure container 7.

The structure container 7 is generally cube or cuboid shaped with a plurality of flexible side walls 11. In this example, the structure container 7 comprises a flexible base 12 and a flexible cover 13. The flexible cover 13 is connected to the base 12 by the flexible side walls 11.

20 25 30 In this example, the structure container 7 is a flexible bag. In this example, the structure container 7 is provided with two handles 14, 15 which are attached to opposing sides of the structure container 7. In other examples there are a different number of handles or the handles 14, 15 may be omitted entirely.

The structure container 7 is at least partly permeable to liquid. In this example, at least one of the base 12 or the cover 13 or at least one of the side walls 11 is permeable to liquid. Consequently, when the structure container 7 is at least partly submerged in water, the water permeates into the structure container 7 to hydrate the contents of the structure container 7.

The structure container 7 is at least partly filled with a dry concrete composition 16, which is shown in the cut-away portion of the structure container 7 in figure 5. In some examples, the dry concrete composition is drymix concrete. In some examples, the dry concrete composition comprises a mixture of dry cement, sand and an aggregate, such as gravel.

In some examples, the method comprises a step of at least partly filling each of the structure containers 7-10 with a dry concrete composition. In some examples, each structure container 7-10 is filled via an aperture (not shown) in the upper side of the structure container 7-10, for instance in the cover 13. In some examples, the method comprises filling the structure containers 7-10 in close vicinity to the location at which the underwater structure is to be constructed. This enables the dry concrete composition to be transported in bulk to the location at which the underwater structure is being constructed, thereby avoiding the need for any off-site assembly. Furthermore, the exact number of required structure containers can be filled with the dry concrete composition, thereby minimising waste.

In some examples, each of the structure containers is flexible and can be flattened and transported easily when empty. Spare empty structure containers can therefore be provided on site easily, in case it transpires that additional structure containers are required for the underwater structure. This maximises the efficiency of the underwater structure construction method compared with conventional methods where it is either too complex or too energy intensive to provide spare structural components, such as rocks or preformed concrete structures.

Once the structure containers 7-10 have been at least partly filled with the dry concrete composition 16, the method comprises positioning a lower layer 17 of the structure containers 7, 8 on a base surface 18, with at least one side wall 11 of each structure container 7, 8 in contact with a side wall 11 of one of the other structure containers 7, 8, as shown in figure 5. The base surface 18 is, in some examples, the seabed if the seabed is suitably level. Alternatively, the base surface 18 may be a foundation structure or another structure which provides a level surface to carry the structure containers 7, 8.

In some examples, the structure containers 7, 8 are positioned by lifting each structure container 7, 8 using the handles 14, 15. In some examples, the structure containers 7-10 are sized such that, when filled with the dry concrete composition, the structure containers may be moved and positioned without the need for heavy machinery. For instance, in some examples, the filled structure containers 7-10 may be moved using a manually operated crane. In some examples, each structure container may be filled with a predetermined quantity of dry concrete composition such that each filled structure container does not exceed a predetermined weight which is below the maximum lifting weight of the apparatus which is being used to move and position the structure containers.

Once the lower layer 17 of structure containers 7, 8 has been positioned on the base surface 18, the method comprises positioning an upper layer 19 of structure containers 9, 10 at least partly on top of the lower layer 17. The weight of the upper layer 19 exerts a downward force on the lower layer 17 which causes the side walls 11 of the structure containers 7, 8 in the lower layer 17 to deform outwardly in the directions indicated generally by arrows 20 in figure 6. This has the effect of causing the side walls 11 of the structure containers 7, 8 in the lower layer 17 which are in contact with one another to be biased in contact with one another. The biasing force causes the side walls 11 which are in contact with one another to deform against one another and minimise gaps between the side walls 11. The area over which the side walls 11 contact one another is thus increased, thereby strengthening the overall structure of the lower layer 17.

Once the structure containers 7-10 have been positioned in the upper and lower layers 17, 19, the method comprises submerging at least part of each of the structure containers 7-10 in water such that the water permeates into each structure container 7-10. As the water permeates into each structure container 710, the water hydrates the dry concrete composition 16 contained within each structure container 7-10. Once the concrete composition has been hydrated, the hydrated concrete composition can be allowed to set over time so that the upper and lower layers 17, 19 form a rigid structure. In some examples, the rigid structure containers 7-10 form a rigid monolithic structure.

In some examples, the method comprises constructing the underwater structure by lowering the structure containers 7-10 into the water and positioning the structure containers 7-10 whilst underwater. In this example, the structure containers are positioned in contact with one another and deform against one another, as described above, before the concrete composition has time to hydrate and set. In other examples, the underwater structure construction method comprises positioning the structure containers 7-10 on a beach while the tide it out and allowing at least part of each structure container 7-10 to be submerged in water from the sea as the tide comes in.

It is to be appreciated that, while figure 6 only shows two layers 17, 19 of structure containers 7-10, in other examples, there are typically further layers of structure containers stacked on top, for instance in a pyramid shape, as shown in figure 3. Each successive layer causes the structure containers in the underlying layer or layers to deform, such that the side walls are biased against one another, thereby increasing the strength of the underwater structure when the concrete composition sets.

Referring now to figures 7-10 of the accompanying drawings, in some examples the method comprises forming a foundation layer 21 before the structure containers are moved into position. The foundation layer 21 is required if, for instance, a portion of the ground or seabed 22 is uneven or sloping, as shown in figures 7-10.

In some examples, the method comprises surveying the ground or seabed 22 and, if the survey identifies a slope in the ground or seabed 22, the method comprises calculating a number of base containers 23, 24 which are required to level the slope in the ground or seabed 22. For simplicity, figure 7 only shows two base containers 23, 24 but it is to be appreciated that a different number of base containers may be required to level the ground or seabed 22.

In this example, each base container 23, 24 is identical to the structure containers 7-10 described above, but each base container 23, 24 is at least partly filled with a gravel 25 instead of the dry concrete composition.

In some examples, the method comprises at least partly filling each base container 23, 24 with gravel. In some examples, the base containers 23, 24 are filled with gravel in the vicinity of the site where the underwater structure is being constructed. The gravel may therefore be transported to the location in bulk, thereby deriving the same benefits described above in relation to the structure containers.

Once the base containers 23, 24 have been at least partly filled with gravel, the base containers 23, 24 are positioned in contact with one another on the ground or seabed 22, as shown in figure 7. Once the base containers 23, 24 are in position, the base containers 23, 24 are ruptured to allow the gravel to escape. For instance, in some examples a knife 26 is used to cut an opening 27 in part of each base container 23, 24, as indicated generally in figure 7. If the foundation layer 21 is being constructed underwater a diver or a remote operated underwater vehicle is used to rupture each base container 23, 24 using a knife 26.

Once the base containers 23, 24 have been ruptured, the gravel 25 from the base containers 23, 24 coalesces to form the foundation layer 21, as shown in figure 8.

As the gravel 25 coalesces and settles due to the effect of gravity, the gravel 25 from the plurality of base containers 23, 24 levels the ground or seabed 22 automatically. An upper surface 28 of the gravel 25 provides a level surface which functions as a base surface to receive the lower layer 17 of the structure containers 7, 8.

The automatic levelling effect of the gravel in the ruptured base containers 23, 24 removes the need for complex structural changes to the ground or seabed 22 in order to prepare the ground or seabed 22 to support an underwater structure. By contrast, when an underwater structure is constructed using preformed concrete blocks the seabed must be prepared and levelled carefully so that the preformed concrete blocks can be positioned precisely.

In the same way as the structure containers described above, the base containers 15 filled with gravel remove the need for heavy machinery. Consequently, a foundation layer can be laid relatively easily, with minimal disruption to the environment.

In some examples, the structure containers and the base containers are 20 constructed from a biodegradable material. In some examples, the biodegradable material is hessian. In other examples, the biodegradable material is a biodegradable plastic. In these examples, the structure containers and the base containers biodegrade naturally in the water, without polluting the sea.

When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included The terms are not to be interpreted to exclude the presence of other features, steps or components.

The invention may also broadly consist in the parts, elements, steps, examples and/or features referred to or indicated in the specification individually or collectively in any and all combinations of two or more said parts, elements, steps, examples and/or features. In particular, one or more features in any of the embodiments described herein may be combined with one or more features from any other embodiment(s) described herein.

Protection may be sought for any features disclosed in any one or more published documents referenced herein in combination with the present disclosure.

Although certain example embodiments of the invention have been described, the scope of the appended claims is not intended to be limited solely to these embodiments. The claims are to be construed literally, purposively, and/or to 10 encompass equivalents.

REPRESENTATIVE FEATURES

Representative features are set out in the following clauses, which stand alone or may be combined, in any combination, with one or more features disclosed in the

text and/or drawings of the specification.

1 An underwater structure construction method comprising: providing a plurality of structure containers, wherein each structure 20 container: comprises a plurality of flexible side walls, is at least partly permeable to liquid, and is at least partly filled with a dry concrete composition, wherein the method further comprises: positioning a lower layer of the structure containers on a base surface, with at least one side wall of each structure container in contact with a side wall of one of the other structure containers; positioning an upper layer of the structure containers at least partly on top of the lower layer so that the weight of the upper layer exerts a downward force on the lower layer which causes the side walls of the structure containers in the lower layer to deform outwardly such that the side walls of the structure containers in the lower layer are biased in contact with one another; submerging at least part of each of the structure containers in water such that the water permeates into each structure container and hydrates the dry concrete composition contained within the structure container; and allowing the hydrated concrete composition in each structure container to set over time so that that the upper and lower layers form a rigid structure.

2. The method of clause 1, wherein the step of providing the plurality of structure containers comprises at least partly filling each structure container with the dry concrete composition.

3. The method of clause 1 or clause 2, wherein the dry concrete composition comprises a mixture of cement, sand and aggregate.

4. The method of any one of the preceding clauses, wherein each structure container comprises: a flexible base; and a flexible cover which is connected to the base by the flexible side walls, wherein at least one of the base or the cover or at least one of the side walls is permeable to liquid.

5. The method of any one of the preceding clauses, wherein each structure container is at least partly of a biodegradable material.

6. The method of any one of the preceding clauses, wherein each structure container comprises a handle and the method comprises lifting and positioning the structure container using the handle.

7. The method of any one of the preceding clauses, wherein lower layer is wider than the upper layer such that the underwater structure has a substantially pyramid-shaped cross-section.

8. The method of any one of the preceding clauses, wherein the method comprises submerging the structure containers underwater at the same time as positioning the structure containers to construct the structure under the water.

9. The method of any one of clauses 1 to 7, wherein the method comprises positioning the structure chambers while a sea tide is out and submerging at least part of the structure containers in water by allowing the sea tide to come in and at least partly cover the structure containers.

10. The method of any one of the preceding clauses, wherein, before the step of positioning the lower layer of structure containers, the method further comprises: providing a plurality of flexible base containers which are each at least partly filled with gravel; positioning the base containers in contact with one another on the ground; and rupturing the base containers to permit the gravel from the base containers to coalesce to form a foundation layer on the ground, wherein an upper surface of the foundation layer is the base surface which receives the lower layer of structure 20 containers.

11. An underwater structure construction method for constructing a foundation layer, the method comprising: providing a plurality of flexible base containers which are each at least partly filled with gravel; positioning the base containers in contact with one another on the ground; and rupturing the base containers to permit the gravel from the base containers to coalesce to form a foundation layer on the ground.

12. The method of clause 10 or clause 11, wherein the step of providing the plurality of flexible base containers comprises at least partly filling each base container with the gravel.

13. The method of any one of clauses 10 to 12, wherein each base container is at least partly of a biodegradable material.

14. The method of any one of clauses 10 to 13, wherein the method further comprises: surveying the ground and, if the survey identifies a slope in the ground, calculating the number of base containers which are required to level the slope in the ground; and positioning the calculated number of base containers on the slope to at least partly level the slope.

15. The method of any one of the preceding clauses, wherein the method further comprises: mounting a walkway to the underwater structure using a plurality of elongate walkway supports such that the walkway is supported in a spaced apart position relative to the underwater structure.

16. The method of any one of the preceding clauses, wherein the underwater structure is a breakwater.

17. A breakwater constructed in accordance with the method of any one of the preceding clauses.

Claims

CLAIMS1 An underwater structure construction method comprising: providing a plurality of structure containers, wherein each structure 5 container: comprises a plurality of flexible side walls, is at least partly permeable to liquid, and is at least partly filled with a dry concrete composition, wherein the method further comprises: positioning a lower layer of the structure containers on a base surface, with at least one side wall of each structure container in contact with a side wall of one of the other structure containers; positioning an upper layer of the structure containers at least partly on top of the lower layer so that the weight of the upper layer exerts a downward force on the lower layer which causes the side walls of the structure containers in the lower layer to deform outwardly such that the side walls of the structure containers in the lower layer are biased in contact with one another; submerging at least part of each of the structure containers in water such that the water permeates into each structure container and hydrates the dry concrete composition contained within the structure container; and allowing the hydrated concrete composition in each structure container to set over time so that that the upper and lower layers form a rigid structure.
2. The method of claim 1, wherein the step of providing the plurality of structure containers comprises at least partly filling each structure container with the dry concrete composition.
3. The method of claim 1 or claim 2, wherein the dry concrete composition comprises a mixture of cement, sand and aggregate.
4. The method of any one of the preceding claims, wherein each structure container comprises: a flexible base; and a flexible cover which is connected to the base by the flexible side walls, wherein at least one of the base or the cover or at least one of the side walls is permeable to liquid.
5. The method of any one of the preceding claims, wherein each structure container is at least partly of a biodegradable material.
6. The method of any one of the preceding claims, wherein each structure container comprises a handle and the method comprises lifting and positioning the structure container using the handle.
7. The method of any one of the preceding claims, wherein lower layer is wider than the upper layer such that the underwater structure has a substantially pyramid-shaped cross-section.
8. The method of any one of the preceding claims, wherein the method comprises submerging the structure containers underwater at the same time as positioning the structure containers to construct the structure under the water.
9. The method of any one of claims 1 to 7, wherein the method comprises positioning the structure chambers while a sea tide is out and submerging at least part of the structure containers in water by allowing the sea tide to come in and at least partly cover the structure containers.
10. The method of any one of the preceding claims, wherein, before the step of positioning the lower layer of structure containers, the method further comprises: providing a plurality of flexible base containers which are each at least partly filled with gravel; positioning the base containers in contact with one another on the ground; 30 and rupturing the base containers to permit the gravel from the base containers to coalesce to form a foundation layer on the ground, wherein an upper surface of the foundation layer is the base surface which receives the lower layer of structure containers.
11. The method of claim 10, wherein the step of providing the plurality of flexible base containers comprises at least partly filling each base container with the gravel.
12. The method of claim 10 or claim 11, wherein each base container is at least partly of a biodegradable material. 10
13. The method of any one of claims 10 to 12, wherein the method further comprises: surveying the ground and, if the survey identifies a slope in the ground, calculating the number of base containers which are required to level the slope in 15 the ground; and positioning the calculated number of base containers on the slope to at least partly level the slope.
14. The method of any one of the preceding claims, wherein the method further comprises: mounting a walkway to the underwater structure using a plurality of elongate walkway supports such that the walkway is supported in a spaced apart position relative to the underwater structure.
15. The method of any one of the preceding claims, wherein the underwater structure is a breakwater.
16. A breakwater constructed in accordance with the method of any one of the preceding claims.