NL1037395C2 - Element for use as a part of a revetment for a water barrier, comprising water permeable material. - Google Patents

Description

Title: Element for use as a part of a revetment for a water barrier, comprising water permeable material

The present invention relates to an element for use as a part of a revetment for a water barrier such as a dike, a bank, or a water-retaining wall.

In many cases, water barriers as mentioned are covered in order 5 to prevent damage of the water barriers, particularly damage as a result of erosion or wave attack. Often, a revetment for a water barrier comprises a plurality of elements which are arranged on the water barrier in an abutting fashion.

Elements for use as a part of a revetment for a water barrier 10 are known in the art. For example, NL 1003138 discloses an element which is made from concrete or a similar material, and which is approximately prismatic in a height direction and has two transverse faces and two longitudinal faces between a top face and a bottom face. In particular, the shape of the faces of the element is such 15 that in a revetment comprising a plurality of abutting elements, open spaces are present between the faces of the elements, for allowing water to pass through.

An alternative to the element known from NL 1003138 is an element which does not so much have a specific shape of its faces, 20 but which is provided with a hole for allowing water to flow from one side of the element to another.

In general, in the field of revetments for a water barrier, it is preferred to have a certain percentage of open spaces in or between the revetment elements, in order to prevent water pressure 25 behind the elements from causing elements to be pressed out of their abutting engagement to elements surrounding them. Severe damage to the revetment can be expected when the revetment is composed without a sufficient amount of open spaces, wherein the spaces may be present between adjacent elements of the revetment and/or in the 30 elements.

In practice, it appears that in spite of measures for realizing open spaces in revetments for water barriers such as dikes or banks, it still happens that elements of the revetments are removed under 1037395 2 the influence of water. In view of this fact, it is an objective of the present invention to provide a new element for use as a part of a revetment for a water barrier, which has another structure and an improved behaviour with respect to existing elements, such that 5 removal of the element from a revetment under the influence of water pressure is less likely to occur, or cannot occur at all under normal circumstances .

According to the present invention, at least a substantial portion of an element for use as a part of a revetment for a water 10 barrier comprises material which is permeable to water. With this element as part of a revetment of a water barrier, it is ensured that water pressure practically cannot build op between the element and the water barrier, due to the fact that at least a substantial portion of the element is permeable to water. This is another 15 concept than the concept which is found in prior art elements, where only a small portion of the elements is permeable to water, namely at the position of holes in the elements and/or recesses at faces of the elements, and where there is still a risk that pressure builds up at the location of another, closed portion.

20 Within the scope of the present invention, it is even possible for the whole element to comprise the material which is permeable to water, so that the pressure reducing effect of the permeability may be optimal. With respect to the water permeability, it is noted that a practical minimum is 25%. Hence, it is preferred if the water 25 permeable material of the element has pores for at least 25% of its volume for letting pass the water.

There are many materials which are suitable to be used in the element according to the present invention. In general, the material may be a bound granular material. The material may be bound in any 30 suitable manner, for example, on the basis of mineral oil such as bitumen, on the basis of polyurethane glue or a similar product, or on the basis of cement, wherein the material may comprise any suitable material such as a stony material, and may comprise concrete.

35 In a practical embodiment, the element may be shaped like a block, so that it is easy to form a revetment with a number of elements. An advantageous consequence of the present invention is that the shape of the element may be relatively simple, as the element may be a block having flat faces, wherein there is no need 40 for a hole in the block. Another advantageous consequence of the '3 present invention is that the element is light-weight in comparison with conventional elements of the same size, so that the element is easier to handle. In general, the elements may be light-weight when the present invention is applied, as weight of the elements is not 5 needed for rendering it difficult for water to remove the elements from a certain position in a revetment, contrary to what is the case in prior art situations where relatively heavy blocks are used. In view of this fact, it is also possible for the elements to have another size than usual, wherein the elements may be smaller or 10 bigger, depending on requirements in specific cases.

The present invention also relates to a revetment for a water barrier such as a dike or a bank, comprising a plurality of elements as described in the foregoing, i.e. elements of which at least a substantial part comprises water permeable material, wherein the 15 elements are arranged on the water barrier in an abutting fashion.

Furthermore, the present invention relates to a revetment for a water barrier, comprising a plurality of block-shaped elements which are arranged on the water barrier in an abutting fashion, and which 20 are having an inclined orientation with respect to the horizontal, wherein ribs of the elements are at an angle with respect to the horizontal. In particular, the angle may have a component of 45° along the water barrier.

In known revetments, it often happens that there is a loose 25 element, i.e. an element which does not experience sufficient pressure from surrounding elements for keeping the element in place in the revetment. An insight underlying the present invention is that this phenomenon is caused by the fact that the elements are piled up in horizontal rows, wherein a number of ribs of the 30 elements are extending more or less parallel to the horizontal. It is clear that loose elements are the first ones to disappear from the revetment when the revetment is exposed to flowing water and waves. Therefore, it is an objective of the present invention to eliminate the risk of having loose elements, and this is done by 35 proposing another positioning of the elements on the water barrier, namely the inclined positioning as mentioned. In this way, it is achieved that there is always a clamping effect of one element to another in a downward direction, so that it is practically not possible for loose elements to occur.

4

The present invention will be explained on the basis of the following description of the invention with reference to the drawing, in which equal reference signs indicate equal or similar components, and in which: 5 figure 1 diagrammatically shows a portion of a revetment as arranged on a dike, which revetment is composed of a number of elements; figure 2 diagrammatically shows a side view of a cross-section of the dike with the revetment shown in figure 1, facing water at the side where the revetment is arranged; and 10 figure 3 diagrammatically shows an element according to the present invention, which is adapted to be used as a part of a revetment for a water barrier.

Figures 1 and 2 show a dike 1 and a revetment 2 which is 15 arranged at one side of the dike 1, namely the side facing the water. The main function of the revetment 2 is protection of the dike 1 against damage, which may occur over time under the influence of water flow and waves.

The revetment 2 is composed of a number of elements 3 which are 20 arranged in an abutting fashion, wherein a layer of small particles (not shown), particularly stones, is present between the faces of the elements 3. In the shown example, the elements 3 are shaped like a block having six flat faces. An example of dimensions of the elements 3 is 50 cm x 50 cm x 25 cm, but many other dimensions of 25 the elements 3 are feasible as well within the scope of the present invention.

A first particular feature of the revetment 2 is that the elements 3 are arranged in an inclined orientation with respect to the horizontal. In particular, ribs 4 of the elements 3 are 30 extending at an angle with respect to the horizontal, wherein a component a of this angle along the dike 1 is preferably 45° as is the case with the shown example. Contrary to known revetments 2, the revetment 2 according to the present invention does not comprise a number of horizontal rows extending on top of each other. Instead, 35 when seen along the dike 1, the revetment 2 according to the present invention comprises a number of rows extending at an angle a with respect to the horizontal. At the top and the bottom of the revetment 2, in order to have a flat top face and bottom face, respectively, half elements 3 are used.

5

An advantage of the shown arrangement of the elements 3 is that there is no risk that loose elements 3 will occur. In this arrangement, each of the elements 3 is always kept in place under the influence of the weight of surrounding elements 3, wherein each 5 of the elements 3, with the exception of elements 3 at the top, is directly associated with three other elements 3 positioned at a higher level. In figure 1, the influence of the weight of one of the elements 3 on two lower elements 3 is indicated by means of arrows.

A second particular feature of the revetment 2 is that there 10 are no holes in the elements 3 or between the elements 3. Still, water pressure cannot occur between the elements 3 and the dike 1, because at least a substantial portion of the elements 3 is permeable to water. Figure 3 shows an example of an element 3, and illustrates the water permeable nature of the element 3. In 15 particular, figure 3 discloses the fact that in the element 3, a pattern of actual pieces of material 5 and holes 6 is present. The holes 6 serve for allowing water to pass and thereby releasing pressure which may otherwise occur between the element 3 and the dike 1..

20 On the one hand, the element 3 needs to be able to protect the dike 1 against the influence of water, and, on the other hand, the element 3 needs to be able to allow water to pass from one side to another. Taking these factors into account, a practical value of the water permeability of the element 3 is at least 25%. With a value as 25 mentioned, the protective function of the element 3 is sufficiently guaranteed, so that damage of the dike 1 under the influence of water is still prevented.

A suitable material for the water permeable portion of the element 3 is a bound stony material, wherein the manner in which the 30 material is bound may be any suitable manner. Other types of material are feasible as well, wherein it is important there is sufficient resistance against the influence of water in order to avoid disintegration of the element 3. Whatever the material may be, it is possible for the whole element 3 to comprise the water 35 permeable material, so that it is guaranteed that water pressure between the element 3 and the dike 1 is low for every portion of the element 3, as a consequence of which it is guaranteed that the element 3 stays in place on the dike 1. Needless to say that less damage of the revetment 2 results in less need for maintenance and 40 an increased level of reliability of the dike 1. Furthermore, due to 6 the presence of holes (pores) 6 in the element 3, the element 3 is light-weight, so that handling of the element 3 is facilitated. It is also possible to have larger dimensions of the element 3, and still have a weight that is acceptable, so that less actions are 5 required for building up a revetment 2 with a number of elements 3.

The present invention may be summarized as follows. At least a substantial portion of an element 3 which is intended to be used as a part of a revetment 2 for a water barrier such as a dike 1 or a 10 bank comprises water permeable material. In this way, it is achieved that the risk of an element 3 breaking loose from the revetment 2 is minimized, as a water pressure prevailing between the element 3 and the water barrier 1 cannot get high as a result of the water permeable features of the element 3. The element 3 may comprise a 15 suitable bound granular material, for example, and may be shaped like a block having flat faces, as there is no need for holes or recesses in the element 3 and its faces.

It will be clear to a person skilled in the art that the scope 20 of the present invention is not limited to the examples discussed above, but that several amendments and modification thereof are possible without deviating from the scope of the invention as defined in the appended claims.

1037395

Claims (14)

An element (3) for use as part of a covering (2) for a water barrier such as a dike (1), a bank, or a water barrier, wherein at least a substantial part of the element (3) comprises material that is water-permeable. 5 Element (3) according to claim 1, wherein the water-permeable material has a water-permeability of at least 25%. 3. Element (3) according to claim 1 or 2, wherein the water-permeable material is a bonded granular material. Element (3) according to claim 3, wherein the water-permeable material is bonded with a petroleum product. Element (3) according to claim 3, wherein the water-permeable material is bonded on the basis of polyurethane glue. The element (3) according to claim 3, wherein the water-permeable material is bonded on a cement basis. 20 Element (3) according to any of claims 1-6, wherein the water-permeable material comprises a stone-like material. 8. Element (3) according to any of claims 1-6, wherein the water-permeable material comprises concrete. The element (3) according to any of claims 1-8, which is formed as a block. A lining (2) for a water barrier such as a dike (1) or a bank comprising a plurality of elements (3) according to any of claims 1-9, wherein the elements (3) on the water barrier (1) are against each other are placed. A covering (2) according to claim 10 as far as dependent on claim 9, wherein the elements (3) have an oblique orientation relative to the horizontal, wherein ribs (4) of the elements (3) are at an angle with the make it horizontal. 12. Cladding (2) as claimed in claim 11, wherein an angle that lies between ribs (4) of the elements (3) and the horizontal has a component (a) of 45 ° as seen along the water barrier (1). 13. Covering (2) for a water barrier such as a dyke (1) or a bank, comprising a plurality of block-shaped elements (3) placed against each other on the water barrier (1), the elements (3) having an oblique orientation with respect to the horizontal, in which ribs (4) of the elements (3) make an angle with the horizontal. A covering (2) according to claim 13, wherein an angle located between ribs (4) of the elements (3) and the horizontal, along the water barrier (1), has a component (a) of 45 °.