GB2205883A

GB2205883A - Method of creating an artificial island

Info

Publication number: GB2205883A
Application number: GB8709122A
Authority: GB
Inventors: Ronald Jarman Bridle
Original assignee: University College Cardiff Consultants Ltd; Cardiff University
Current assignee: University College Cardiff Consultants Ltd; Cardiff University
Priority date: 1987-04-15
Filing date: 1987-04-15
Publication date: 1988-12-21
Also published as: GB8709122D0; GB2205883B

Abstract

An artificial island is constructed by driving piles 1 into the sea or lake bed 2, constructing a retaining face by means of blocks or panels or other in filling between or around the piles, filling the structure with hydraulic fill material some of which escapes at the bottom to form a sloping ramp 7 and protecting the surface of this ramp against erosion. The structure may be reinforced by ties or mats attached to the elements of the face to help retain them against the pressure of the in fill material and to reinforce the structure. In an alternative method of construction the face may be constructed by wrapping material round lines lowered into the water from the surface. <IMAGE>

Description

11 2205883 METHOD OF CONSTRUCTING ARTIFICIAL ISLANDS AND LAND EXTENSIONS

The invention relates to a method for constructing an island in or an extension of land into a body of water for example the sea, an estuary or a lake.

The invention is defined in the claims appended hereto and embodiments of it will now be described with reference to the accompanying drawings in which:- Figure 1 is a fragmentary elevation in section through an artificial island of generally oval outline; Figures 2 and 3 show reinforcing means applicable to the construction of Figure 1; and Figure 4 shows an alternative construction for an island or extension of land onto the bed of the sea or a lake.

Referring first to Figure 1, in the construction of an artifical island, piles 1 are driven into the seabed 2, the piles are arranged around the perimeter of the intended island. Around the outline defined by the piles a retaining face is constructed for retaining fill material deposited within the piles. The face may comprise polymer or othd material wrappe d round the piles or by blocks or panels 3 of any suitable material supported by the piles. The blocks or panels may interlock with the piles or with another for additional security and to provide better sealing against the leakage of the hydraulic fill material which, as will be described later, forms the main body of the artificial island.

1 2 For additional support, a employed. These ties 4 extend panels forming the face and a central anchorage 5. They perform the dual function of maintaining the face against the pressure exerted by the fill material and of acting as a reinforcement for the fill after it has settled in position. In addition to the main ties 4, extending between the anchorage and the blocks or panels of the face subsidiary ties 6 may extend from the main ties 4 to the face blocks or panels. The arrangements of the ties is shown in plan in Figure 2.

Another method of reinforcement which serves the purposes both of anchoring the face and of reinforcing the filling is by means of mats formed by transversely crossing strips extending between the face panels. These mats may be built up from strips of net, fastened at their ends to the insides of the face panels, both ties and nets may be employed in combination in the same structure.

Once the structure is completed, hydraulic fill material is. pumped into it. As this material settles some escapes at the bottom of the structure below the retaining face where It forms a sloping surface or ramp 7 having a low angle of slope. Filling is continued until the structure is filled to above the water level 8.

system of ties may be betwe.en the blocks or 1 t, 1 3 The surface of the ramp 7 is then treated to protect it from scouring by the action of the water. This may be done by conventional methods used for the prevention of errosion or by the provision of artificial seaweed.

The edge of the structure where it protrudes from the water surface may be protected against errosion by wave action by providing pre-cast units of suitable material for example reinforced concrete 9 hanging over the edge and anchored internally to the structure.

The island may be completed by a layer of soil planted with trees and shrubs etc., for humanity purposes or it may be used to support buildings or other structures on its surface.

The hydraulic fill may comprise material-dredged from the seabed in the neighbourhood or locally available waste material or a combination of both thereby avoiding the cost of bringing fill materials from a distance.

The example just described was an island of oval form but the structure need not be an island it can be an extension of land into the sea or a lake or estuary or the in filling of a bay in the shoreline but the general method of construction is the same.

A further example of the invention will now be described with reference to Figure 4.

1 4 In the example described above, piles were first driven into the seabed and the fill retaining face was built up from below, such process necessarily requiring underwater work by divers. In the embodiment to be described, the base structure is built up at the water surface level and lowered to the sea or lake bed as the case may be.

In this embodiment, a number of stout lines 20 each bearing at its lower end a vacuum anchor 21 are lowered in the required positions for example from moored pontoons. As the lines are lowered, a cover 22 of suitable material for example a polymer is wrapped round the outside of the ring of guidelines and fixed to each line. The wrapping process is continued as the lines are lowered and ties or reinforcing mats may be added at suitable intervals as indicated in the example described with reference to Figures 1, 2 and 3.

As before, the structure is completed by pumping in the hydraulic fill protecting the ramp 7 which is formed at the base of the structure by the escaping in fill material against errosion and providing a seal 9 if necessary for additional protection against wave action.

This latter method of construction avoids the need for divers or frogmen to work underwater to affix the face material.

CC

Claims

C L A I M S: 1. A method of constructing an island in or an extension of

land into water, the method comprising the steps of.

i. constructing a retaining face for retaining hydraulic fill material; il. pumping hydraulic fill material into the space bounded by the retaining face so that part of the fill material escapes below the retaining face to form a ramp of low slope; and iii. protecting the ramp surface from scouring.
2. A method according to Claim 1 in which the face comprises piles supporting panels or blocks.
3. A method according to Claim 2 in which the panels or blocks are arranged to interlock one with another.
4. A method according to Claim 1 in which the face comprises piles or guidelines around which material is bound.
5. A method according to any preceding claim in which tie lines are fixed to the elements of the face structure to support them against the pressure of the in fill and to reinforce the in fill material.
6. A method according to any preceding claim in which mats are fo.rmed by strips extending from side to side of the structure and attached to elements of the face to support them against the pressure of the in fill and reinforce the structure. 1 6
7. A method according to any preceding claim in which the ramp is protected against scouring by artificial seaweed.
8. A method according to any preceding claim in which units are provided at the water surface to protect the structure against wave action.
9. A method according to Claim 1 in which the retaining face comprises material wrapped around guidelines which are lowered from the water surface.
10. An artificial island constructed by a method according to any preceding claim.
11. A construction according to any preceding claim comprising a portion of shoreline extended into water.

Puclished 1988 at TI.e Patent Oflice. State House. 66 '1 Righ Rolborn, London WC1R 4TP. FiMher cepies maybe obtained from The P4tent Office, t 1 i 17