GB2299606A

GB2299606A - Improvements in or relating to barriers

Info

Publication number: GB2299606A
Application number: GB9607225A
Authority: GB
Inventors: Albert Norman Derbyshire
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-04-05
Filing date: 1996-04-04
Publication date: 1996-10-09
Anticipated expiration: 2016-04-04
Also published as: GB9607225D0; GB2299606B

Abstract

A barrier for resisting the effects of sea or other water flow on a surface consists of containers 11 laid in rows and provided with means 18 for securing adjacent containers to each other and a support surface e.g. a sea bed. The containers 11 are perforate and are wholly or partly full of flowable material e.g. sand, unset concrete, which has been placed in the container away from land e.g. pumped into the container. The containers can be placed on the surface and filled from a vessel or filled on a vessel and lowered to the surface.

Description

IMPROVEMENIS IN OR RELATING TO BARRIERS THIS INVENTION relates to barriers and methods of making or erecting barriers.

According to one aspect of the invention a method of erecting a barrier for resisting the effects of a sea or other water flow on a surface comprises placing flowable material into a container away from land and placing the container on the surface.

The container may be placed on the surface before the material is placed into the container. The container may be above a site and material be placed into the container and the container then lowered to the site. The material may be pumped into the container.

A barrier may comprise a plurality of said containers end-to-end.

A barrier may comprise a plurality of rows of said containers.

The container may be perforate.

Securing means may secure the container to the surface and adjacent containers. The invention includes a barrier erected as above.

From another aspect the invention provides a barrier for resisting the effects of sea or other water flow on a surface containing flowable material.

The container may be full of the material. The invention also provides a vessel comprising means for applying flowable material to a container and placing the container on a surface.

The invention may be performed in various ways and one specific embodiment with possible modifications will now be described by way of example with reference to the accompanying schematic drawings, in which: Fig. 1 is a side view of a barrier; Fig. 2 is a plan view of the barrier of Fig. 1; Fig. 3 is a section through Fig. 1; Fig. 4 shows another barrier; Figs. 5 and 6 show laying of a barrier; Figs. 7 and 8 are side and plan views of a barge.

Figs. 9 to 11 illustrate barriers; Fig. 12 and 13 are plan views of the barge; Fig. 14 illustrates possible container or container sections; and Fig. 15 illustrates a barrier.

The invention relates to apparatus and methods for creating underwater barriers to combat or lessen the detrimental effects of storms, waves or current flow on coastal areas, for example a coastal region between high and low tides, and marine constructions and pipelines.

A barrier 10 comprises one or more perforate containers 11 into which a flowable material is delivered. The container 11 is anchored or fixed to the supporting surface, typically the sea bed 12 and to adjacent containers 11 if used. Typically the barrier 10 would comprise a number of similar containers 11 end-to-end to form a row 13 but a heavier barrier may comprise two adjacent rows 13, 14 or superposed rows 13, 14, 15 as illustrated in figures 1 to 3. Typically each row would be completed in turn. The size of the containers 11 both in diameter and length can be selected for appropriate circumstances and may depend for example on the depth of water above the barrier, the conditions under which the barrier is laid or constructed, the reasons for constructing the barrier e.g. temporary or permanent.The container 11 may be fitted with internal frames and stringers of, for example, plastics or metal for strengthening or supporting purposes and may also, as referred to later, be formed with compartments by the provision of dividing walls 16 which may themselves provide added stiffness and support as appropriate for different conditions of use. Each container 11 is provided with fixing points 17 which can be used to secure anchoring devices 18 to the sea bed 12 if desired or if necessary initially and/or as fastening points for parallel rows of containers when a larger barrier is installed. Adjacent containers or sections 11 of the overall barrier are joined together by use of the fixing points e.g. as indicated at 18 to construct a continuous barrier of any desired length.

Material 19 delivered into the container 11 is flowable and is preferably pumped into the container. The fill material 19 is preferably composed of material similar to that in the sea bed underneath the container and may for example be sediment or other material dredged or removed from an area adjacent to the barrier, or brought to the barrier from other areas having a similar sea bed sediment or material. However a selected material, for example concrete, can be used. Examples of suitable material are sand, pebbles, stones, clay, concrete or mixtures of two or more of these; or other material selected or approved by a relevant authority.

The container 11 is preferably flexible and may for example be constructed of a plastics fabric e.g. nylon. However mild steel can also be used.

If the barrier 10 is being used to protect marine constructions, for example the leg of an oil platform, the barrier will preferably be contoured, as seen in plan, to have a shape or form corresponding to the construction being protected. In a case where the barrier is protecting a pipeline 60, the barrier would normally extend on both sides of the pipeline, see Fig. 4, and the region above the pipeline may itself be protected by further barriers as indicated at 21.

The container 11 is perforate so that sea water can be displaced during filling. In the case where the container is made of rigid material, for example mild steel, the perforations can be made after the container has been constructed. The ends 22 of the container would normally be imperforate. If a fabric is used for the container then this may be porous or additional holes can be constructed in it.

The perforations may be covered by a fine mesh; concrete pumped in would then displace the water through the fine mesh. The effective size of the perforations is related to the fill material.

Fig. 14 illustrates sections of a container.

Section 70 is part 70a non-porous and part 70b has a plastics e.g. nylon fine mesh, for example for a fill of sand or other fine material. Section 71 is similar but wholly porous. Sections 72, 73 show wire mesh of different size for example for a fill material of differing sizes of stone. The wire mesh may be plastic coated.

Section 74 is of reinforced plastics having a non-porous area 74a and porous fine mesh parts 74b on lower and upper areas, for example, for a fill of concrete. This illustrates various possibilities for a container.

Figs. 5 and 6 illustrate one method of installing the barrier, particularly for shallow water. A shallow draft vessel carrying lifting gear 31 lowers a section 11 into place on the sea bed 12 and divers can secure the container either temporarily or permanently through anchoring devices 18. Fill material is then be pumped into the container or barrier section either from the vessel 30 or from a dredging vessel 31 via hose 32. On completion of filling, the hose 32 is disconnected and the vessel 30 installs the next container and fills it. Divers then secure the two containers together, and so on.

FIgs. 7 and 8 illustrate a barge 40 suitably adapted for use as a laying vessel and/or as a combined dredging and laying vessel. Main propulsion and positioning of the vessel can be, for example, by water jet. The vessel has a hull 41, and in the hull is a well 42. The well accommodates a construction comprising a holder 43 for a container 11 to be filled, and a ramp 45 by which the container 11 can be lowered into place on the sea bed 12. The ramp is covered by removable deck gratings 45a. The forward end of the ramp is pivoted at 46 and additionally or alternatively the ramp can be lowered to a position below the hull to give a lesser angle of tilt if desired.

The barge will not sink as the ramp area is a "free flooding" section of the barge, which is constructed of three basic parts, Bow section, Port and Starboard sections. These sections are sub-divided into watertight compartments comprising mainly dead air space, ballast tanks and machinery space. The Port and Starboard "pontoons" 62, 63 are connected to each other by frames 61 extending the full width of the barge commencing aft of region 50 and continue to the stern.

The vessel 40 has a deck 47 and on the starboard side adjacent to the forward end of the well 42 is dredging and pumping machinery 48. This gives the barge or vessel the ability to dredge its own filling material or to accept filling material from another vessel.

On the port side of the well is a container 49 that initially accepts the fill and directs it to separate compartments 60 of a container 11 to be filled via pipes 51 which connect the containers 11, 49 detachably together. The container 49 can be moved on rails 52 so that it can be moved to one side of the well when a fresh container 11 is to be lowered into the well ready for filling, and moved back over that for filling. The after part of the deck is occupied by a temporary store 53 for further containers.

At the stern of the deck is a lifting frame 54 with winches. Anchors 55 can be positioned at each corner of the deck for use in stabilising the vessel during the laying procedure.

Superstructure 56 includes bridge, control room, mess. The ramp is shown dotted in its position for lowering a container to the sea bed.

The barrier may be entirely under water but the barrier could be part under water and part on, for example, a beach.

It will be appreciated that the container is wholly or partly filled away from land as distinct from being filled on land and then transported to the barrier site. The container can be at sea above or adjacent a site and be partly or wholly filed and then lowered to the site; if partly filled, filling will then be completed.

Fig. 10 shows silting or accumulation of e.g. sand behind the barrier after erection.

The containers 11 may have lateral portions enabling adjacent and/or superposed containers to be interlocked to resist separating movement.

In one arrangement the containers engaging the support surface have a flat underface.

In one form of operation the container or barrier is essentially continuous and is progressively filled similarly to a sausage machine and progressively laid on the support surface. A trapezium section (Fig. 15) is suitable here, allowing fitting together of adjacent barriers. The adjacent barriers can be secured together and to the surface as above.

Claims

1. A method of erecting a barrier for resisting the effects of sea or other water flow on a surface comprising placing flowable material into a container away from land and placing the container on the surface.

2. A method as claimed in Claim 1, in which the container is placed on the surface before the material is placed into the container.

3. A method as claimed in Claim 1, in which the container is spaced above the surface and material placed into the container and the container then moved to the surface.

4. A method as claimed In Claim 3, in which the container is lowered to the surface.

5. A method as claimed in any preceding claim, in which the material is pumped into the container.

6. A method as claimed in any preceding claim, in which the barrier comprises a plurality of said containers end-to-end.

7. A method as claimed in any preceding claim, in which the barrier comprises a plurality of rows of said containers.

8. A method as claimed in any preceding claim, in which the container is perforate.

9. A method as claimed in any preceding claim, in which the container is full of the material.

10. A method as claimed in any preceding claim, comprising securing means for securing the container to the surface and for adjacent containers.

11. A method as claimed in any preceding claim, using a vessel comprising means for applying flowable material to a container and placing the container on a surface.

12. A method of erecting a barrier substantially as hereinbefore described.

13. A barrier erected by a method as claimed in any of Claims 1 to 12.

14. A barrier for resisting the effects of sea or other water flow on a surface, the barrier containing flowable material.

15. A vessel comprising means for applying flowable material to a container and placing the container on a surface.