EP0607349B1 - Water retaining reservoir structure - Google Patents

Abstract

PCT No. PCT/FR92/00930 Sec. 371 Date Jun. 8, 1994 Sec. 102(e) Date Jun. 8, 1994 PCT Filed Oct. 7, 1992 PCT Pub. No. WO93/07345 PCT Pub. Date Apr. 15, 1993A structure having at least one layer (3.1), for example three layers (3.1, 3.2, 3.3), of a number of juxtaposed sheet blocks, in which the sheets are shaped so as to define between themselves a series of vertical cells for water storage, and a series of horizontal cells in the height of the blocks for water drainage. The horizontal cells communicate with the vertical cells. The structure is light, inexpensive, easy to install without requiring heavy handling means, and is especially useful in underground water reservoirs.

Description

The subject of the present invention is a block of juxtaposed sheets and a reservoir structure of reservoir, formed of a set of these blocks, intended for various uses, for example as a pond buried rainwater reservoir during very strong rain, this structure then being connected to a network water intake and drainage collector.

As we know, the continuous development of urban agglomerations results in an increase waterproofed floor surfaces. In particular, parking lots (shopping centers, airports, leisure parks, etc.) and urban roads are generally or almost waterproof surfaces, on which rainwater quickly flows towards sanitation networks. These waterproofings have prohibits direct infiltration of rainwater. he As a result, during very heavy precipitation, such as those that occur during thunderstorms, collectors designed for relatively high flow rates low can be saturated and flooding in area urban happen.

Another consequence of these overloads of water drainage networks (case of unitary networks) is the direct discharge of polluted water into the receiving environment through storm spillways, which can have particularly harmful effects on the ecosystem.

When the insufficiency is limited to certain sections of the network, reinforcements are possible, but when the whole network approaches saturation it is necessary to find new solutions, the reinforcement of a section that can lead an overflow downstream. To deal with these problems, it is necessary either to delay considerably flows (several hours sometimes being necessary), or eliminate any flow (by infiltration rainwater for example), or even combine these two solutions. This is possible by means temporary retention of rainwater, by retention basins in the form of underground reservoirs.

Works, such as parking lots, roadways, sports grounds etc, integrating into their structure the storage of rainwater in porous material, are part of these solutions, and are called "structures reservoirs ". The porous material then has at minus two functions: hydraulic and mechanical, and is generally located below the level of natural terrain. This allows it to easily collect runoff water.

WO-A 8 802 422 thus discloses a reservoir structure buried water reservoir, the upper part of which is constituted by a structure with parallel vertical cells between them, resting on a lower part of horizontal drainage of water, formed for example of or porous material.

Such a tank structure takes a long time to install, and further requires means of implementation heavy work, so that its realization is very expensive. In addition, its lower drainage structure can after a while, be clogged with buildup of sand entrained by the waters, and thereby making the entire structure inoperative.

US-A-4,917,536 discloses a structure for the water storage only, consisting of an assembly alternating flat sheets and profiled sheets in form of "egg basket". In such a structure water can only flow vertically between flat sheets, in the housings of the profiled sheets, so that no circulation drainage function horizontal water is not possible, nor in the structure, nor below because no drainage layer is not planned.

US-A 4,880,333 describes a sheet system also shaped like an egg basket, interposed between flat vertical sheets arranged in serpentine shape. Such a device allows to drain in the soil filtering liquids for example of a septic tank, therefore in small quantities, but is not obviously not suitable for water storage and drainage abundant rainfall.

The invention aims to provide a structure tank that is simple and quick to set up, whose cost price is therefore considerably decreased compared to that of the structure known above, and which cannot be clogged with sand or waste.

The invention relates to the use of a block according to claim 1.

In such a block, arranged so that the longitudinal cells extend vertically, water can enter through the horizontal cells and then fill gradually the vertical alveoli.

The tank structure also targeted by the invention conforms to claim 2.

The horizontal cells are distributed over the greater part of the length of the vertical alveoli, that is to say blocks, and ensure the drainage of water practically from top to bottom of the blocks, while that the vertical storage cells ensure the mechanical strength of the assembly.

The fact that this structure is combined to simultaneously perform the functions of drainage and water storage and then vertical runoff of water, greatly reduces the labor required, as well as the cost price of the structure herself. It is advantageously carried out in one suitable plastic, such as for example polystyrene, polypropylene or polyvinyl chloride, or any other thermoplastic material. These blocks alveoli are particularly light while having mechanical resistance which can be adjusted as required, which therefore saves heavy and expensive means handling required so far for install the bottom drainage layer.

Other features and advantages of the invention will appear during the description which goes follow, made with reference to the accompanying drawings which illustrate an exemplary embodiment not limiting.

Figure 1 is a schematic elevational view of an embodiment of the tank structure according to the invention, in which this structure is part of an underground water retention basin.

Figure 2 is a perspective view of a block constituting the alveolar structure according to the invention.

Figure 3 is an elevational view of the element of alveolar structure of Fig. 2.

• une membrane étanche 1, une partie alvéolaire 3 formée de trois couches superposées 3.1, 3.2 et 3.3, un géotextile 4, une couche de remblais 5 (ou de déblais utilisés en remblais), et enfin une couche superficielle 6 de terre végétale.

The structure of the water retention tank shown in Fig. 1 includes, from the bottom up:

• a waterproof membrane 1, a cellular part 3 formed of three superposed layers 3.1, 3.2 and 3.3, a geotextile 4, a layer of fill 5 (or cuttings used as fill), and finally a surface layer 6 of topsoil.

The alveolar structure (3) communicates laterally with collectors 7 supply and 8 evacuation water accumulated in this structure, at the ends which are provided with ventilation tubes 9, 11 vertical, which lead into the peripheral zone of the tank, in manifolds 7 and 8.

The wall 7a of the collector 7 contiguous to the face vertical terminal of structure 3 is perforated on almost its entire height, while the collector outlet 8 is pierced with openings at the lower part of the structure 3.

Structure 3 consists of a set of blocks 12 with juxtaposed cells (Fig. 2 and 3). Each element or block 12 is formed by the assembly of a series of identical sheets 13 ... 18 suitably profiled so as to present a succession of bosses rectilinear 19 and rectilinear recesses 21 delimited by two consecutive bosses 19. These recesses or grooves 21 and the bosses 19 are alternated in both transverse and longitudinal directions of so as to be staggered. So in the same longitudinal direction, a boss 19 is located between two recesses 21, as well as in the transverse direction. Inclined plates 23 form the zones of transitions between the bosses 19 and the recesses 21.

The tops of the bosses 19 form flat rectilinear 19a, alternating on each side of the median plane from sheet 13, ... 18.

Two sheets are assembled by gluing or welding of their bosses 19 facing each other by their plates 19a, delimiting between them these and the recesses 21 of the longitudinal cells 22.

The succession of dishes 23 of two sheets contiguous delimits between these two leaves alveoli transverse 10 perpendicular to the longitudinal cells 22, and whose section is in rhombus. These cells 10 communicate with the successive cells 22, thus interconnected and whose opposite ends, open, form the end faces of block 12.

The lengths of the successive zones arranged in staggered steps can be variable, from same as the number of successive zones for the same item 12.

In the example illustrated in the drawings, each sheet 13 ... of a block 12 of sheets 13-18 contains three longitudinal zones A, B, C, in which the bosses 19 and recesses 21 are staggered, the central zone B being substantially of length double that of each of the two end zones A and C. These areas are separated by parallel rows transverse cells 10. On two opposite sides of a block 12, the edges of the sheets delimit between them cells 22 open longitudinally (Fig. 2) in the zones A and C due to the spacing of these edges (for example 17a and 18a). On the other hand in the central zone B, these edges are contiguous and therefore separate the cells open areas A and C.

We can increase the number of cells 10 for favor the drainage function over the function retained water storage, the 10 extreme cells being then close to the opposite ends of the blocks 12.

A set of blocks 12 suitably juxtaposed and placed so that their longitudinal cells 22 are vertical, resting on one of their end faces, can therefore form a reservoir structure.

In the example shown in Fig. 1, this structure is made in three superimposed layers: a first layer 3.1 of a height h1, equal by example to that (A + B + C) of an element 12; then arranged on the first layer 3.1, a second layer 3.2 of height h2 lower than that hl of the first layer 3.1. The second layer 3.2 is obtained by cutting of a series of blocks 12, identical to those of the first layer 3.1 and lower structure 2, below of its upper cells 10 to a level K (Fig. 3) neighbor of these. So the height h2 is slightly lower than A + B. Finally the third layer 3.3, placed on the intermediate layer 3.2, consists of the juxtaposition of a set of elements truncated 20 constituting the upper ends cut above level K of elements 12, and turned 180 °. It follows that the cells 10 of truncated elements 20 are found just below the upper surface of the structure 3.

The water holding tank structure which just described being buried and connected to a network drainage as shown in Fig. 1, its technical effect is as follows.

Rainwater reaches the collector 7 by means not shown, known per se. Of there they enter structure 3 through the ends horizontal cells 10, then gradually fill the vertical cells 22, which store thus the accumulated water. This water is then discharged in the collector 8 by the lower cells 10. The water circulation is symbolized by the arrows on Fig. 1.

It should be noted that as a variant the collector 7 can be located at a different location that lateral to the tank structure 3, for example in a middle area thereof. In this case the second collector wall 7 is of course suitably perforated like wall 7a and a second evacuation collector 8 associated is required.

• Elle empêche avantageusement le piégeage d'air au fur et à mesure de la montée progressive du niveau de l'eau à l'intérieur de ladite structure. En effet, l'air progressivement chassé dans la partie non remplie par l'eau s'évacue par les alvéoles horizontaux 10 vers les évents 9 et 11, par lesquels il est rejeté à l'atmosphère. En l'absence des alvéoles horizontaux 10 dans la partie supérieure 3 et des évents 9, 11, l'air serait progressivement comprimé par la montée des eaux et provoquerait un soulèvement des déblais 5 et de la couche superficielle 6.
• Les alvéoles horizontaux 10 accélèrent le remplissage du réservoir grâce à la communication qu'ils établissent entre les alvéoles verticaux 22.
• Le drainage de l'eau est assuré sur presque toute la hauteur de la structure 3, grâce à la suppression de la structure drainante inférieure classique. On élimine ainsi l'épaisseur de cette structure drainante, et donc les travaux de terrassement correspondants.
• Les feuilles 13, 14..., réalisées par thermoformage de matière plastique, peuvent avoir une épaisseur variable, par exemple 1mm, ce qui permet de régler au mieux leur résistance mécanique (avantage qui ne peut être obtenu avec des structures fabriquées par extrusion). En effet, une masse posée sur le sol au-dessus de la structure réservoir 3 exerce sur les couches successives 3.3, 3.2, 3.1 des pressions décroissantes de haut en bas. Il en résulte que la résistance mécanique des différentes couches peut être ajustée aux pressions subies. C'est ainsi que l'épaisseur de la couche supérieure 3.3 sera supérieure à celle de la couche intermédiaire 3.2, qui elle même sera supérieure à celle de la couche inférieure 3.1. Cette réduction d'épaisseur allège l'ensemble et donc facilite sa pose.
• La hauteur des alvéoles horizontaux 10 les plus bas peut avantageusement être relativement élevée. En effet, cela permet alors de recueillir dans les extrémités inférieures des alvéoles verticaux 22 le sable entraíné par les eaux. Ce sable ne peut colmater les alvéoles horizontaux 10 les plus bas, contrairement aux structures drainantes connues, de sorte que la fonction drainage est toujours assurée, malgré le sable accumulé.

In addition to the technical advantages already mentioned, this tank structure has the following:

• It advantageously prevents the trapping of air as the water level inside the said structure gradually rises. Indeed, the air gradually expelled in the part not filled with water is evacuated by the horizontal cells 10 towards the vents 9 and 11, through which it is discharged into the atmosphere. In the absence of the horizontal cells 10 in the upper part 3 and of the vents 9, 11, the air would be progressively compressed by the rise in water and would cause a lifting of the cuttings 5 and of the surface layer 6.
• The horizontal cells 10 accelerate the filling of the reservoir thanks to the communication which they establish between the vertical cells 22.
• Drainage of water is ensured over almost the entire height of structure 3, thanks to the elimination of the conventional lower drainage structure. This eliminates the thickness of this draining structure, and therefore the corresponding earthworks.
• The sheets 13, 14 ..., produced by thermoforming of plastic material, can have a variable thickness, for example 1mm, which makes it possible to adjust their mechanical strength as well as possible (advantage which cannot be obtained with structures manufactured by extrusion) . Indeed, a mass placed on the ground above the reservoir structure 3 exerts on the successive layers 3.3, 3.2, 3.1 decreasing pressures from top to bottom. As a result, the mechanical resistance of the different layers can be adjusted to the pressures undergone. This is how the thickness of the upper layer 3.3 will be greater than that of the intermediate layer 3.2, which itself will be greater than that of the lower layer 3.1. This reduction in thickness lightens the assembly and therefore facilitates its installation.
• The height of the lowest horizontal cells 10 can advantageously be relatively high. Indeed, this then collects in the lower ends of the vertical cells 22 the sand entrained by the water. This sand can not clog the lowest horizontal cells 10, unlike known drainage structures, so that the drainage function is always ensured, despite the accumulated sand.

The example of the structure (2,3) of Fig. 1 is not limiting, the vertical structure 3 can consist of a single layer formed of elements (such as 12 for example), of suitable height, or of several sub-layers of identical or different heights.

Other variant embodiments can be planned. So depending on the number and dimensions sheets (13 ...), the rectangular blocks 12 correspondents can have variable dimensions, appropriate for each intended use.

On the other hand these parallelepipedic blocks can be used to support any of their faces, always having horizontal cells drainage and other vertical storage.

It is also possible, in at least part blocks 12, to orient every other sheet with its bosses 19 perpendicular to the bosses of the two adjoining sheets to which it is attached. This arrangement improves the drainage function.

The leaves can also, in all or part, be perforated to increase the effectiveness of the drainage.

• Utilisation pour l'allégement des remblais sur sols mous, la structure pouvant être utilisée en remplacement de tout ou partie d'un remblai, ce qui permet de réduire efficacement le tassement des sols mous. Cette technique est particulièrement adaptée au voisinage des ouvrages d'art fondés sur pieux, ou dans les zones de transition sols compressibles/substratum rocheux. Elle arrête de façon économique la poursuite de tassements inacceptables.
• Utilisation comme réservoir enterré de retenue des eaux pluviales, notamment des eaux particulièrement abondantes dites "décennales". Cette utilisation, illustrée à la Fig.1, permet de stocker les eaux dans la structure 2, 3, puis les eaux ainsi recueillies sont évacuées à des débits compatibles avec le réseau d'assainissement existant (collecteurs 7, 8).
• Utilisation de la structure comme chaussée poreuse : après infiltration directe au travers des couches de chaussée (enrobé drainant et grave drainante), l'eau est stockée dans la structure de réservoir selon l'invention, puis restituée, soit par infiltration dans le sol, soit par conduit dans le réseau.

The tank structure according to the invention is capable of numerous applications, among which the following will be cited:

• Use for the relief of embankments on soft soils, the structure can be used to replace all or part of an embankment, which effectively reduces the compaction of soft soils. This technique is particularly suitable in the vicinity of structures based on piles, or in the transition zones compressible soils / bedrock. It economically stops the pursuit of unacceptable settlements.
• Use as a buried reservoir for retaining rainwater, particularly particularly abundant water called "decennial". This use, illustrated in Fig. 1, makes it possible to store the water in the structure 2, 3, then the water thus collected is discharged at flows compatible with the existing sanitation network (collectors 7, 8).
• Use of the structure as a porous pavement: after direct infiltration through the layers of pavement (draining asphalt and draining gravel), the water is stored in the reservoir structure according to the invention, then returned, either by infiltration into the ground, either by conduit in the network.

Claims (9)

1. Use of a block (12) of identical juxtaposed sheets, to form a reservoir structure (3) for retaining and draining water, characterised in that the sheets (13....28) in this block are shaped so as to define between them a set of straight longitudinal cells (22) and straight transverse cells (10) which allow communication between the longitudinal cells, the latter being open at their opposite ends.
2. Reservoir structure for retaining water, characterised in that it comprises at least one layer (3, 1) of juxtaposed blocks (12), each comprising identical juxtaposed sheets (13....18), shaped so as to define between them a set of straight longitudinal cells (22) and straight transverse cells (10) which allow communication between the longitudinal cells, the latter being open at their opposite ends, in that these blocks (12) are arranged so that the straight longitudinal cells (22) extend vertically for storing water, and the straight transverse cells (10) extend horizontally for the horizontal circulation or drainage of the water between intake collectors (7) and discharge collectors (8); in that each block (12) comprises assemblies of identical sheets (13, 14,...18) profiled so that they each have a succession of straight bosses (19) and straight recesses (23) alternating in the transverse and longitudinal directions, each sheet being fixed by its bosses to the two adjacent sheets, defining between the latter the horizontal (10) and vertical (22) cells; in that, in at least some of the blocks (12), one sheet (13...) in two is oriented so that its bosses (19) are perpendicular to the bosses (19) of the adjacent sheets to which this sheet is fixed.
3. Reservoir structure for retaining water according to claim 2, wherein the blocks (12) are arranged so that the straight longitudinal cells (22) extend vertically for storing water, and the straight transverse cells (10) extend horizontally for the horizontal circulation of the water between intake collectors (7) and discharge collectors (8).
4. Structure according to claim 3, characterised in that the horizontal cells (10) pass through the vertical cells (22) and are distributed over the majority of the length of the vertical cells.
5. Structure according to claim 2 or 4, characterised in that it comprises a first layer (3.1) of a specified height (h1), a second layer (3.2) of a height (h2) less than that of the first, obtained by cutting out a structure (12) identical to that of the first layer (3.1) below its upper horizontal cells (10), and a third layer (3.3) formed by turning the remaining part (20) of said cutout structure (12) back through 180 degrees, so that the upper row of horizontal cells (10) is close to the upper surface of said third layer (3.3).
6. Structure according to one of claims 2 to 5, characterised in that each block (12) comprises assemblies of identical sheets (13, 14, ...18) shaped so that they each have a succession of straight bosses (19) and straight recesses (23) alternating in the transverse and longitudinal directions, each sheet being fixed by its bosses to the two adjacent sheets, thus defining between them the horizontal (10) and vertical (22) cells.
7. Structure according to one of claims 2 to 6, comprising two or more superimposed layers, characterised in that the thickness of the sheets constituting each layer decreases from the top layer (3.3) to the bottom layer (3.1).
8. Structure according to claim 6, characterised in that, in at least some of the blocks (12), one sheet (13...) in two is oriented so that its bosses (19) are perpendicular to the bosses (19) of the adjacent sheets to which this sheet is fixed.
9. Structure according to any one of claims 2 to 8, characterised in that perforations are provided in at least some of the sheets (13...).

Images