GB2426026A - Automatic buoyant flood barrier - Google Patents

Abstract

A flood barrier includes an impermeable flexible membrane 1 attached to rigid covers 6 which will automatically rise from ground level 9 as the floats 7 respond to flood waters 11. The membrane 1 is held in a backfilled trench 2 and may be protected by slabs of concrete 4 or other suitable material. Flexible ties 3 and optional anchor ties 16 may maintain stability of the barrier during flood. The backfilled trench 2 may incorporate a box structure (17, Fig 3) with hinged covers 6 or have concrete or other suitable edgings to support the covers 6 where traffic or other loading is anticipated. The covers 6 and floats 7 may be positioned slightly above ground 9 to provide a faster response in the event of a tidal wave or tsunami and shock absorbers may be attached to the ties 3 to reduce wave impact.

Description

I

Flood Barrier The invention relates to the need to protect land and property from flooding during rise of adjacent waters above normal levels. It replaces a conventional fixed flood protection wall or bund, and avoids the physical and visual intrusion of the conventional flood protection wall or bund.

The invention is constructed in a trench with most of the excavated soil replaced.

When not required the barrier rests unobtrusively close to ground level. If flooding occurs the barrier automatically rises with the flood waters to protect the land and property behind.

The barrier is constructed of an impermeable flexible membrane which is partly buried in a trench below ground level. The membrane is attached to rigid covers and floats which rise with the rising water to provide the necessary protection. Resistance to the water forces is provided by the membrane and flexible ties using the weight of soil in the backfilled trench and, if necessary, by the addition of suitable ground anchors.

The barrier may be constructed within a rigid frame of concrete, polymer or other material where it is to be subject to vehicle traffic or other loading.

The barrier may be constructed slightly above existing ground level to provide a more rapid response to a tidal wave or tsunami.

A preferred embodiment of the invention will now be described with reference to the accompanying drawings in which: FIGURE 1 Shows a side view of the barrier as constructed ready for use in the event of flood.

FIGURE 2 Shows a side view of the barrier after activation by flood waters.

FIGURE 3 Shows a side view of the barrier with alternative use of box frame structures in the backfi lied trench to maintain stability and alternative attachment of the floats by wrapping the membrane around and securing.

As shown in Figures 1 and 2, the barrier is constructed to protect the ground and property at 10 assuming the flood waters 11 will approach from the lower ground 9.

A trench is excavated and a suitable continuous flexible, impermeable membrane 1 such as reinforced polymer is placed against the sides of the trench and it is backfilled with the excavated soil 2. Slabs of concrete or similar 4 rest on the compacted backfill 2 to assist with general stability. Where the weight of soil 2 is insufficient to resist the forces due to the water 11, ground anchors such as Duckbill anchors' and flexible ties 16 are installed for additional resistance.

The Continuous membrane I is connected to the slabs 4 at point 12 and at point 13 together with the flexible ties 3 and anchor ties 16 where installed for additional stability.

The membrane is attached at points 5 and 14 to rigid covers 6 constructed of suitable materials such as plastic, wood or lightweight compounds. The flexible ties 3 and, if necessary, anchor ties 16 are attached at point 5 such that the membrane I and covers 6 are restrained in a near vertical position in the event of flood.

The membrane 1 may be used as the flexible ties 3 provided drainage holes are incorporated in the tie length to allow the free passage of water.

Suitable floats 7 having sufficient buoyancy to raise the covers 6, are attached to the membrane 1 and covers 6 at point 15. Alternatively the floats 7 may be attached by wrapping and securing the membrane I around the floats. (Figure 3) The membrane 1 is continuous (constructed in sections with suitable water tight joins) along the length of ground to be protected from flooding with sufficient pleating to allow for erection from horizontal to vertical as ground contours change and curves in the barrier alignment are accommodated.

The slabs 4 and covers 6 may be of suitable dimensions for ease of construction and accommodation of changes in horizontal and vertical alignment of the barrier.

The backfill zone 8 is of coarse gravel or similar of high permeability to allow the water immediatc access to the float 7 in times of flood.

Concrete or other suitable material may be placed at the edges of the backfilled trench or box structures 17, of a form similar to a polymer crate, placed in the trench (Figure 3) to provide stability and support the covers 6 in the event of traffic or other loading when the barrier is not in use. The box structures may have rigid sidewalls 18 to replace the concrete slabs 4 and suitable access holes 19 for the flood waters.

The box structures may replace the underground section of the membrane 1 with the membrane attached and sealed to the boxes at 20 and adjacent boxes connected to each other for example by bolts 21 linking the sidewalls 18 with water tight seals between them. The flexible membrane I may act as the hinge or the covers 6 may be attachcd to the box structure by suitable hinges 22 Where a tidal wave or tsunami is anticipated the cover 6 and float 7 may be positioned slightly above ground level 9 for more rapid response of the barrier to the surging water. The impact of the wave may be reduced by the inclusion of shock absorbers which may be lengths of suitably resilient material attached to the ties 3 to come into effect when the covers 6 reach a near vertical position.

Claims (10)

1. I. A flood protection barrier including an impermeable flexible membrane entrapped within a backfihled trench and rigid covers which rest at or near ground level and which rises automatically on floats during flood conditions.
2. 2. A barrier as claimed in claim 1 where stability is maintained by flexible ties, which may be an extension of the membrane in claim 1, entrapped in a backfihled trench.
3. 3. A barrier as claimed in claim 1 or claim 2 where stability is maintained by ground anchors attached to the barrier by flexible ties.
4. 4. A barrier as claimed in any preceding claim where stability is maintained by the membrane, flexible ties and ground anchor ties attached to a slab of concrete or suitable material within a backfilled trench.
5. 5. A barrier as claimed in any preceding claim where stability is maintained by the membrane, covers, flexible ties and ground anchor ties attached to box structures of concrete, polymer or suitable material in a backfihled trench
6. 6. A barrier as claimed in any preceding claim which when not in use rests unobtrusively at or near ground level protected by covers of suitable material.
7. 7. A barrier as claimed in any preceding claim and having concrete or other substantial edges to the backfilled trench to support the covers in the event of traffic or other loading.
8. 8. A barrier as described in any preceding claim and positioned when not in use slightly above ground level to provide faster response of the floats to a tidal wave or tsunami.
9. 9. A barrier as described in any preceding claim where wave impact forces are absorbed by shock absorbers which may be of resilient material attached to the flexible ties or other suitable form.
10. 10. A flood barrier substantially as herein described above and illustrated in the accompanying drawings.