EP1466054A1

EP1466054A1 - Method and device for limitation of flooding

Info

Publication number: EP1466054A1
Application number: EP02755996A
Authority: EP
Inventors: Holger Sandvik
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-08-27
Filing date: 2002-08-27
Publication date: 2004-10-13
Anticipated expiration: 2022-08-27
Also published as: DE60230448D1; NO318292B1; WO2003018915A1; ATE417966T1; NO20014160L; NO20014160D0; EP1466054B1

Abstract

A method is described to prevent or limit floods of floodwater, in which a barrier to the water is established in that a suitable length of a chamber-forming element, formed by a watertight material, is arranged, and means to keep the material in close contact with a foundation, and the element is filled to a given pressure by a medium such that the element is fully inflated and forms the barrier. The method is characterised in that the element is filled with a homogeneous fluid having a specific gravity that is higher than the specific gravity of the floodwater so that the element's close contact with the foundation is strengthened. An alternative method and a device for +carrying out the method is also described.

Description

METHOD AND DEVICE FOR LIMITATION OF FLOODING.

The present invention relates to methods and a device for prevention or limitation of flooding by floodwater, as it is described in the subsequent patent claims 1 and 9.

Flooding or floods often occur in most places on earth as a consequence of large amounts of rain, intense and rapid melting of snow and glaciers, tidal waves (wind combined with spring tide), and for other reasons, and this often results in great damage to the environment and property. In many places such flooding occurs regularly every year, such as during the spring when the snow melts in the mountains. When this water is collected in the larger streams/rivers out onto flat land, it often leads to large land areas being flooded. To prevent damage to buildings, builtup areas, individual houses, harbour sites and other sites, retaining walls or dykes are built to the necessary heights to keep the water away when the flooding arises .

The extent of such floods is still difficult to predict, and when there is a danger that the water will flow over such a retaining wall or the like (or flow into areas which perhaps have never been flooded previously) , sand or earth are the most common, and normally regarded as the most easily available, aids one has. The sand/earth is as a rule put in bags (such as bags made of jute) that can be handled manually or with a crane (e.g. on a tractor or the like) , and the bags are placed in layers, layer by layer, along the area that is threatened. This is effective for prevention of water penetration, but is very labour intensive. The problem with flooding is that running water has a strong excavating effect so that if it first starts to flow over the edge of the earth/sand mound, the water will dig out a ditch that gradually gets larger and gives a stronger and stronger excavating flow of water.

There are also known solutions in which a pumpable mixture of sand and water is fed into extended chamber- forming sacks. One section, for example a side section, of the sack is made from a water permeable cloth material so that the water can penetrate out of the cloth and leave the sand inside the sack. Then, only the sack with its content of sand functions as the barrier to the flood- water. The water functions in all such solutions only as an aid/transport medium, i.e. to make it easier to feed the sand into the extended sacks .

Such solutions are known from the following patents GB 2,197 902; US 3,957,098; US 3,957,098 and DE 44,17,672.

Another method of approach is to let the sack be filled with water only as a barrier. However, one must then use special means to be able to keep the sack down against the foundation, and it is known to use sacks with concrete or lead mats in the bottom layer. Such solutions are described in the following patents US 5,865,564; US 5,993,113 and DE 28,15,256.

Therefore, it is an aim of the present invention to provide a new method to prevent water from passing the mentioned barrier or flood areas where surface water is undesirable.

Furthermore, it is an aim to provide a new device to carry out the method.

The method and device according to the invention are characterised by the features that are defined in the subsequent claims 1 and 8. The preferred embodiments are given in the dependent claims .

The new device according to the invention is very simple to handle. Firstly, large lengths of the chamber- forming element (in the form of a hose bag or sack) can be rolled up into a single 'coil that both takes up little space during storage and that is easy to transport to the place of use. Furthermore, at the place of use it is easy to roll out, and then it is simple to fit a pump to the inlet mouthpiece (hose connection) and start the pumping in of the very medium that is most accessible, namely water, especially sand/earth containing water or sludge, for example, heavy drilling mud that is used in the oil industry. It is important that the lower section of the element, such as in the form of a hose bag or sack, seals tightly against the foundation so that no floodwater can penetrate between the sack bottom and the foundation to prevent the hose bag becoming excavated. The heavy medium/fluid contributes greatly to this in that it forces the bottom mat powerfully down against the foundation. The sack can also comprise stay ropes along the sack and these can be secured to the ground to obtain extra pressure and anchorage of the hose bag to the foundation. It is also possible to stabilise the sack by placing sandbags against the hose at a given mutual distance apart.

Preferably the bottom section of the hose bag has a square cross section, and is preferably wider in the bottom (viewed in cross section) than in the upper part. This is to achieve sufficient stability against the foundation. If the hose bag is completely round in cross section, it can more easily start to move (roll) when it is subjected to the sideways influences from the pressure of water.

According to the invention the sack comprises an upper and a lower hollow space that are kept apart by a perforated, water-permeable, fibrous cloth dividing wall that extends in the longitudinal direction of the sack. The dividing wall lets water through to the upper hollow space but retains particles (sand) that are suspended in the water. The cloth can also comprise a net cloth (preferably pliable and flexible) that has mesh openings of such an order of magnitude that the particles are held back, while the water is let through. With this solution the water/sand mixture (the medium) is pumped into and through the one end of the lower hollow space that will then be filled with the water/sand mixture. The water will filter through the cloth and fill up the upper hollow space. Afterwards the water pressure is maintained in the upper hollow space to a full application pressure so that the hose bag is fully inflated while the sand lies in the lower chamber and provides the necessary pressure against the foundation.

According to an alternative main solution of the invention, a heavy fluid, such as a drilling fluid, is used. In this case the dividing wall is not necessary, and the bag/sack forms a single chamber that is filled with the ballast fluid (drilling fluid) of a composition such as is described below.

According to the most preferred embodiment of the invention, the sack comprises three sack sections, one central main sack and a side sack on each side of the lower part of the main sack. The three sack sections are mutually coupled together, such as by welding, so that they are connected and in cross section form a triangular pattern as the subsequent figure shows.

The main sack is manufactured from a watertight material, such as a relatively thick cloth that can be reinforced.

The side sacks are preferably tight, i.e. a tight dividing wall against the main chamber, if they shall be filled with a heavy and basically homogenous fluid, such as a homogenous suspension, such as drilling mud, which has a larger specific gravity than floodwater, such as up to 1.6 g/cm³. (The specific gravity of water is 1 g/cm³) . Drilling sludge is a mixture of water, clayey soil (mainly in a powdery form) and chemicals in a mixing ratio that gives the desired density (specific gravity) and rheological properties (flow properties and consistency) . Barium sulphate (barite) is a commonly used ingredient/- chemical in drilling mud/fluid, and is a heavy mineral that in itself has a specific gravity of 4.5 g/cm³. Normally, a drilling fluid has a time-limited homogeneity of up to 5-7 weeks. Thereafter, a part of the powdery particles starts to separate out from the water and settles .

Each side sack comprises a feed pipe for filling of the liquid into the sack body until the sack is full and the sackcloth fully inflated, while the main chamber is filled up with water only (for example the floodwater itself) . When both the sacks are filled with the ballast fluid, they will be forced down against the foundation, as a consequence of the higher specific density of the fluid, while an established water pressure in the main sack keeps it fully inflated. With the use of heavy drilling sludge, the sack becomes much more resistant to the buoyancy it is subjected to when the floodwater level rises. It is important to use sludge types that do not harm the environment if/when it is released into the floodwater. Most of the water-based sludge types have such positive characteristics. The specific gravity should be regulated in relation to the characteristics of the floodwater (specific gravity).

Alternatively, the lower sack section or the two sack sections are filled with heavy particles, such as stone, gravel, sand, iron-ore concentrated particles or iron- containing pellets. According to one example, the specific gravity of sand in dry condition is 1.6 g/cm³. Then, a sack material that lets through water but retains the heavy particles is used, so that the sack is eventually completely filled with heavy particles. Thus, the sack is gradually getting heavier and heavier as a consequence of these particles. The heavy particles, for example sand, are then led into the sacks as a pumpable heterogeneous suspension, i.e. the particles are in a mixture with water. By vigorous stirring they are kept in motion and the sand is "floating" in the water so that the suspension is pumpable and can be fed into the hose. The rolled up sack/hose bag can quickly be rolled out along the area that one wishes the flow water shall be stopped. Thereafter the sack is blown up into an extended sausage shape by the aid of the fluid/water that contains ballast material, either by the fluid having a higher density than water, or with the aid of a suspension with solid particles, as it is explained above.

The invention shall now be explained further according to a preferred example, with reference to the subsequent description of the tool and the enclosed figures 1-9.

Figures 1A and IB show schematically a situation in which the buildings in association with a quay are protected against the water by means of a barrier or an extended sack according to the invention.

The figures 2A-D show a vertical section of a first embodiment of the sack (hose bag) according to the invention.

Figure 3 shows a section of the hose bag according to figure 2 in a part perspective outline.

Figure 4 shows a vertical section of a second embodiment of the barrier hose/sack according to the invention.

Figures 5A-C show a vertical section of a third embodiment of the sack according to the invention, i.e. how a series of sacks/hose bags can be mutually connected so that a sufficient sealing action is obtained.

Figure 6 shows an alternative anchorage method of the hose/bag.

Figure 7 shows an alternative and preferred construction of a sack according to the invention.

Figures 8 and 9 show a sack construction that is used to join together two mutually adjacent sacks, so that a good seal between the sacks is obtained.

Initially reference shall be made to figures 1A and IB which show a situation where water, for example, as a consequence of a spring tide 10, threatens the buildings 12 that stand on a quay area 14. To prevent this, a barrier 16 is placed on the foundation 13 in the form of a sack (hose bag) 16 around the buildings 12. In figure IB, the normal flood level is shown by 18, while the spring tide level, that leads to flooding, is shown by 20.

Figure 2 shows (in four stages) the filling of the hose bag/sack 10 in cross-section. Figure 2a shows the bag in its approximate flat state as it looks when it is rolled out from its rolled up/coiled state, while the other figures 2b-2d show the bag as it is gradually filled and fully inflated with water 22 (collected from the floodwater (fresh water or seawater) , or a ballast material in the form of drilling fluid or the like. The hose bag 16 will then form a barrier against the rising tide coming into the quay 14.

The bag is manufactured from a relatively thick cloth of plastic or corresponding watertight and strong material, that can withstand mechanical forces (overpressure from water and air) without bursting etc. The plastic cloth is preferably reinforced. The part of the bag which shall lie against the foundation can, as an extra precaution (see figs 2A-D) , include a lower extra heavy layer 30, such as a lead mat or inserted lead treads. Thereby, the hose/bag can still be rolled up.

The sack/hose bag can easily be emptied of water and rolled up for transport and storage and be rolled out to be used at new use locations.

Figure 4 shows a main solution according to the invention, in which the hose bag 16, with the aid of a cloth 34 (a perforated layer), i.e. inserted horizontally, is divided into two chambers, upper chamber 36 and lower chamber 38.

A mixture of water and particles (sand) in a well- stirred state, is pumped in with great force into the lower chamber 24 through a separate pipe 32 connected to the bag at 35. The water will at all times percolate through the water permeable cloth 34 and into the upper chamber 36. Thereby, the ballast material of particles, such as sand, is accumulated in the lower chamber 38 and ensures that the hose bag gets a low centre of gravity and is forced against the foundation (the surface of the quay) 13. The upper part is gradually completely filled with the watery part of the mixture and is kept fully inflated by the water pressure.

The hose bag according to the invention can be comprised of shorter individual sections that are mutually connected. An example of how this can be solved is shown in the figures 5A-5C.

Figure 5A shows the bag 16 which is blanketed by a cover 40 (such as tarpaulin) which, with the aid of side straps 42, can be secured to the anchorage points 44 that can comprise metal rings 44 which are already fastened to the surface of the quay.

Arranged on the short side 46 of the bag, i.e. the side that shall be connected to an adjacent bag, are straps, chains or the like 48 which are fastened to the end of an adjacent bag 50 (figure 5B) . The bags that shall be joined together are put out in a flat state. The straps 48 are fastened between the adjacent bags 16,50 and the bags are filled with the homogenous water mixture with a higher density, or the suspension of water and solid ballast particles. As the bags 16,50 bulge out at the meeting end edges, these end sections are forced against each other with great force so that a secure seal between the two adjoining bags 16,50 is obtained. Thereafter, the straps/ropes 42 are fastened to the quay surface rings 44 and the straps, and thus the cover, are tightened up so that the bags 16,50 make good contact with the foundation. Figure 5C also shows a solution in which the upper part of the bag comprises a feed pipe 60 for filling of water or water/sand mixture. The figure shows a solution in which a bleed pipe 62 is connected to the bag at its lower part at 64. When the bag 16 is filled up, the end 66 of the pipe 62 is squeezed tight to the upper side of the bag. The reference number 68 suggests an inner cloth which forms a second lower chamber 70 that can be filled with ballasting sand, while the water percolates upwards into the upper chamber 70.

According to a preferred solution, the lower part of the hose bag is wider in the bottom (viewed in cross- section) than in its upper part, this is to create greater stability.

Figure 6 shows an extra anchorage method of the hose/bag. According to this solution, an extended piece of tarpaulin 70 is first placed on the foundation on which the barrier shall lie, the tarpaulin 70 being wider than the area which will be taken up by the barrier bag 16. Then, the bag is put down and filled with water. Thereafter, ballast/stones or the like 72 are placed on top of the tarpaulin 70, against the bag and further along at regular intervals. Then the tarpaulin 70 is folded upwards, from both sides, over the upper surface of the bag and tied together at the top. This will make a strong and safe anchorage of the barrier bag.

Figure 7 shows another and preferred embodiment of the sack construction according to the invention. It is shown lying down on a quay 14 to protect against a storm surge. The normal tide level is shown by 18 while the spring tide level that leads to flooding is shown by 20.

The sack construction comprises three chamber forming hose-shaped sack sections (that are watertight at each end) , a centrally lying main sack 80 and a side sack 82,84, on each side of the main sack 80, which each form a chamber that can be filled with a medium. The side sacks 82,84 have approximately the same length as the main sack and are watertight in each end. The main sack 80 and the side sack 82 are joined together (such as by welding) by way of a joint wall section 81, while the side sack 84 is joined to the main sack 80 by way of a joint wall section 83.

The three sack sections form in cross-section an approximately triangular shape. The side sacks 82,84 are arranged low down on the side of the main sack 80 so that the widest part of the construction lies against the foundation 13 that is the surface of the quay and stabilises the whole construction.

The main sack is manufactured from a watertight material, as mentioned previously, and is arranged to be filled with water so that the cloth is fully inflated and forms a floodwater barrier with a given height.

The side sacks 82,84 are preferably also manufactured from a watertight cloth if they shall be filled with a heavy, mainly homogenous, liquid suspension, such as drilling sludge.

According to the second especially preferred embodiment, the side sacks 82,84 are completely watertight, with the exception of the two joint wall sections 81,83 respectively, which they share with the main sack. The two sidewalls 81,83 comprise a perforated water permeable cloth, a net cloth or the like. When the particle-containing water is pumped into the sacks 82,84 through the pipes 90,92, the water further continues into the main sack 80, fills and expands this while the particles (the sand) are retained in the side sacks. The whole construction remains lying steadily against the foundation without rolling or sideways movements as a result of the two side sacks being filled with sand, while the water fully inflates the main sack and forms the real barrier to the floodwater. The side sacks/chambers contribute to keeping the sack forced down against the foundation and thus contribute to the slowing down of, or prevention of, excavations underneath the bag.

Each side sack 82,84 comprises a feed pipe 86,88 with a pipe 90,92 for supply of the fluid into the sack body. When both side sacks 82,84 are filled, they will be forced down against the foundation, as a consequence of the higher specific gravity of the fluid or by the particles that will finally fill the side sacks. It can be seen in figure 7 that the main sack 80 comprises clips 100a, b,c on its outside to hook up the pipes (which include stop valves) so that they do not fall down to the ground level and the fluid runs out of the sack again. The figures 8 and 9 show a sack construction that is used to join together the two mutual edge-to-edge adjoining bags 80a, 80b (which are watertight in each end), so that one achieves a good seal between the two adjoining sacks. Each end edge of the sacks 80a, 80b comprises a wide belt 85 and 87, respectively, which is folded up and round a loose sausage-like sack 89. The smaller sausage-formed sack 89 sideways covers the joined area between the sacks 80a, b and can be filled with sludge or sand. Thereafter, the belts 85,87 are folded upwards and locked together with ropes 91 or similar fastening methods. Thereby, one has obtained a watertight join area between two main sacks .

When pumping a heterogeneous suspension of water and solid particles, there is a limit to how far it can be pumped through a sausage-formed sack before the particles start to sink and form a layer at the bottom. Therefore, each independent sack should be of a limited length. With the folding technique which is described above, a long sack can be fitted together with a series of part sacks of smaller lengths. When one uses a homogenous ballast fluid from a drilling fluid, one does not have such limitations.

Thus, according to the invention, a new method and device which can make prevention of floods simpler and safer than it previously has been possible, is provided. The greatest advantage with the new solution according to the invention lies in that one has a need for much less sand that what is known previously, for example from the above mentioned publications, at the same time as one uses water (the floodwater itself) as the main element in the barrier/sack. This will also simplify the cleaning up tasks when the barrier shall be removed.

Furthermore, it will be preferred that the side chambers (i.e. the walls in the side chambers 82,84) can be opened so that the sand can be removed. The sack can thereby be easily cleaned and made ready to be used again.

Claims

P A T E N T C L A I M S

1. Method to prevent or limit flooding of floodwater, where a barrier to the water is established by a suitable length of a chamber-forming element manufactured from a watertight material, and means to keep the element in close contact with a foundation, and the element is filled to a given pressure with a medium so that the element is fully inflated and forms the barrier, characterised in that the element is filled with a homogeneous fluid with a specific gravity which is higher than the specific gravity of the floodwater so that the element' s close contact with the foundation is reinforced.

2. Method according to claim 1, characterised in that the fluid is a heavier liquid, such as a suspension or drilling fluid, the specific gravity of which is regulated with regard to the characteristics of the floodwater.

3. Method according to claim 1, characterised in that a drilling fluid with a time-limited homogeneity, such as up to 5-7 weeks, is used.

4. Method to prevent or limit flooding of flood water, in which a barrier to the water is established in that a given length of a chamber-forming element, manufactured from a watertight material which comprises means to keep it in close contact with a foundation is set up, and the element is filled with water to a given pressure so that the element is fully inflated and forms the barrier, characterised in that the element is filled with a suspension of water and particles which has a higher specific gravity than the specific gravity of the flood- water, as the water/particle mixture is fed into one or several lower sections (38 ; 82, 84) of the element which, with perforated dividing wall (38; 81, 83), respectively, is separated from a preferentially upper main section (36,80) of the element so that the solid particles are accumulated in the lower section (s) while the water flows through the perforations in the dividing wall(s) and is made to inflate the upper main section (36,80) of the element.

5. Method according to claim 4, characterised in that a suspension of water and heavy particles, stone, gravel, earth, sand, iron-like particles, or iron-containing pellets, etc. is used.

6. Method according to any of claims 4-5, characterised in that the applied chamber-forming element is divided into an upper (36) chamber and a lower (38) chamber, with the fluid as a mixture of water and particles (sand) being pumped, in a well mixed state, into the lower chamber

(34) .

7. Method according to any of claims 4-6, characterised in that the applied chamber-forming element is divided into a central main chamber (80) and two lower chambers (82,84), one on each side of the main chamber, with the fluid as a mixture of water and particles (sand) being pumped, in a well mixed state, with great force into the two lower chambers (82,84) with the water flowing on to the central chamber (80) while the particles remain in the lower chambers, respectively.

8. Method according to any of the preceding claims, characterised in that the applied chamber-forming element is manufactured from a watertight material, such as a relatively thick cloth that can be reinforced, in which the element preferably has a form of an extended hose, or sack, that is fully inflated by being filled up water.

9. Device to prevent or limit floods of floodwater, comprising a chamber-forming element with means to keep it in close contact with a foundation, and the element is arranged to be filled to a given pressure with a medium so that the element is fully inflated and forms the barrier, characterised in that the element is divided into one or more lower sections and one upper main section, with the lower sections being separated from the main section by a water permeable (perforated) material (81,83), and the lower chamber (s) comprising means to pump in the medium that shall fill the chambers.

10. Device according to claim 9, characterised in that the element is divided into two chambers, an upper chamber (36) and a lower chamber (38), said chambers being separated by the perforated water permeable body (34) .

11. Device according to claim 9, characterised in that the element is divided into a central main chamber (80) and two lower chambers (82,84), one on either side of the main chamber, and the two chambers (82,84) are separated from the main chamber (80), respectively, by a perforated water permeable body (81,83).

12. Device according to any of claims 9-11, characterised in that the element is designed to be stored coiled or folded up, and brought to the location it is to be used where it is rolled out or folded out, and the bottom part of the hose bag is wider in the bottom (viewed in cross- section) than in its upper part.

13. Device according to any of preceding claims characterised in that the chamber-forming element is manufactured from a watertight material, such as a relatively thick cloth that can be reinforced, and the element has preferably a hose form or a sack form and can be fully inflated by filling up with water.