EP0843049B1 - Apparatus and methods to create perviousness in a trench wall - Google Patents

Abstract

The system consists of a duct through the partition (1) between two trenches filled with a drainage material. The duct has a shutter which can be in the form of a rotary plate or an inflatable balloon, controlled from the surface by a rod or tube (8) running through the middle of the partition wall. Once the structure being protected by the underground partition wall has been completed the duct can be opened to allow a normal flow of ground water.

Description

The invention relates to a device and methods for create permeability in a tight wall in the ground.

We often need to make one or more walls waterproof in the ground, for example to protect a site underground against floods that could be caused by the surrounding aquifer. Once the work completed, the watertight walls remain in place and obstruct the natural circulation of water underground, which can have drawbacks notables. In particular, there may be a rise in the level of the aquifer resulting in exerting a considerable push on the wall (s) waterproof that can cause damage to the wall itself and also cause infiltration into structures neighbors.

To date, to the knowledge of the Applicant, process or system for creating easily permeability in a tight wall in the ground. Until now, we had to resort to painful excavation work and locally perforate or destroy the wall, once an adequate depth is reached.

It would therefore be desirable to be able to easily create permeability in a tight wall so that the groundwater circulation is restored.

The present invention aims precisely to provide a system and method for easily creating, at desired moment, localized permeability in a wall waterproof in the ground.

More specifically, the invention relates to a device for creation of water permeability in a waterproof wall buried in the ground, comprising said wall buried in the ground, an element tubular for the passage of water through the wall, and shutter means operable from the surface of the ground allowing either to block or to clear the passage formed by said tubular element.

The element can be centered in relation to the wall waterproof and, therefore, embedded in said wall, or else be at contrary, eccentric with respect to the sealed wall, the tubular element then being embedded in a molded element in the soil next to the wall.

The invention also relates to methods for realization of such a device.

A first method for producing such a device, useful when the waterproof wall is made of a material low mechanical strength, such as a hardenable grout, is characterized in that it includes the realization of a excavation, under excavation fluid, coming to cut transversely the wall with positioning in said excavation of a tubular element comprising a part perennial central tubular of relatively material resistant, closed tubular end parts removable in a relatively fragile material, and a means temporarily closing said actuatable central part from the surface by a control means, said element tubular extending transversely to the sealed wall with the eliminable end portions projecting through relative to the wall, then after hardening of the fluid excavation or replacement thereof with a grout curable and hardening thereof, to eliminate closable end parts removable from the tubular element and finally to bring the closure means in the open position 5 at the desired time for the creation of the permeability.

Preferably, at least one trench filled with permeable material in which opens one end of the tubular element after elimination of eliminable end portions.

According to a particular mode of implementation, the elimination of at least one of the extreme parts is excavated under excavation fluid, a trench in line with the extreme part to be eliminated using a excavation tool which cuts the fluid or grout hardened and destroy said eliminable end portions, said trench then being filled with a material permeable, so as to act as a collecting trench or water dispenser.

A second method for producing such a device, useful especially when the waterproof wall is made in one high mechanical strength material, such as reinforced concrete or not, and delimits a raft or a pit, is characterized in that it consists: (a) to produce, under fluid excavation, an excavation adjacent to and perpendicular to the watertight wall to be produced, (b) to be placed in this a tubular element comprising a part perennial central tubular of relatively material resistant, closed tubular end parts removable in a relatively fragile material, and a means temporarily closing said central part and actuable from the surface by a control means, harden the excavating fluid or to substitute a curable grout and to harden it, so as to form a hardened grout bar including the tubular element, then (c) to make the trench with an excavation tool where the waterproof wall will be molded making sure cut the bar previously with the excavation tool carried out and destroy the extreme eliminable part of the tubular element facing the wall, (d) pouring the concrete in the trench with the result that the end of the tubular element, adjacent to the wall, is taken in the concrete after setting, (e) to excavate the ground on the side of the watertight wall opposite the bar down to a level lower than that of the tubular element, (f) to be made, at the end of the bar opposite the watertight wall, an excavation making sure cut the said bar with the excavation tool and destroy the other removable extreme part of the element tubular, (g) to pierce the watertight wall, from the side of the wall released in step (e), where finds the tubular element, to establish a passage extending the lumen of the tubular member through the waterproof wall, and finally (h) to bring the sealing means in the open position at the desired time for the creation of the permeability. It should be noted that the order of execution of the steps (e) to (h) is not critical and could be different from that shown. For example, step (e) could follow step (f) rather than precede it, and step (h) could be carried out at an earlier stage.

Preferably, the excavation carried out in step (f) is then filled with permeable material.

The excavation in which the element is positioned tubular can have any horizontal section by rectangular or circular example. An excavation of rectangular section can be made using a tipper type excavator. A circular excavation can be produced by a drill.

The perennial central part of the tubular element is made of a relatively strong material (for example metal), while the closed end portions eliminable are made of a relatively fragile material (for plastic example).

The sealing means may consist of an element inflatable, such as a balloon, which can be inflated and deflated from the ground surface. Alternatively, a valve could be used as a reversible closure.

The following description made with reference to appended drawings will make the invention clear.

Figures 1a to 1d are schematic plan views illustrating the embodiment, according to the invention, of a system creating permeability in a tight wall.

Figure 1e is a cross-sectional view along the line X-X in Figure 1d.

Figure 2 is a schematic perspective view of a tubular element used in this embodiment.

Figures 3a to 3e are schematic plan views (Figures 3a to 3d) and in vertical section (Figure 3e) illustrating a variant of the system of the invention and its production.

The general reference 1 designates a waterproof wall made, for example, by pouring into a trench of a curable grout. At the location of wall 1 desired for the implementation of the system, we carry out in a conventional manner, under excavation fluid 2, an excavation 3 across the wall by coming to cross the latter. The depth of the excavation is substantially equal to that of the wall, although this is not essential (Figure 1a). We then descends into the trench, to the depth desired (usually to the bottom of the excavation) a tubular element, designated by the general reference 4, arranged transversely to the wall and passing through it in part.

This tubular element 4, illustrated in detail on the Figure 2, includes a central part 5 for example in metal in which a conduit is threaded in a centered fashion 6, closed at its ends by lids 7, for example in plastic material, longer than that of the part 5, but slightly less than the length of the excavation 3. The element 4 further comprises a tube 8 perpendicular to the central part 5, connected to the latter and communicating with the interior of the conduit 6 by means of adequate holes provided on the central part and conduit 6 and extending to the top of the surface of the ground. The element finally comprises an inflatable balloon 9 located at the interior of the conduit 6, to the right of the tube 8, which can be inflated or deflated from the ground surface with a small pipe 10 running through pipe 8.

After replacing the excavating fluid with a grout hardenable and set, or after hardening excavation fluid itself, the tubular element 4 found embedded in the hardened mass of the molded strip 11 in excavation 3 (Figure 1b). The lids 7 prevented however that the inside of the tubular element 2 is not overgrown with grout. We then excavate, under fluid excavation, two trenches 12 parallel to the wall 1 and perpendicular to the tubular element 4 making sure that the excavation tool used comes to cut the parts ends of the bar 11 and destroy the extreme parts sealed from the conduit 6 of the tubular element 4 (figure 1 C). Then we replace the excavating fluid filling the trenches 12 with permeable material suitable, such as gravel 13 or the like, for obtain the system shown in FIGS. 1d and 1e.

Then, when you want to create a permeability in the sealed wall, to deflate the balloon 9 to allow groundwater to pass to one side of the wall to the other by taking the passage provided by the tubular element.

It should be noted that, if desired, the tubular element could be fitted with a membrane allowing passage selectively water and stopping pollutants or other unwanted substances. Also, if desired, one or the two trenches 13 could be lined with reactive materials for selectively arresting pollutants or other undesirable substances. Finally, always if desired, the tubular element could be provided a valve, for example of the ball type, in order to only allow the passage of water in one direction, which is interesting when the waterproof wall delimits a volume of polluted or contaminated land.

Figures 3a to 3e illustrate the realization of a variant of the system according to the invention in which the element tubular, instead of being centered relative to the wall, is off-center on one side of it. This variant is useful especially when the waterproof wall is made of concrete, armed or not, and delimits a raft or a pit.

In this case, it is not possible to easily make a bar across the wall waterproof and so we have to do it differently, for example as following :

We start by carrying out the excavation 3 under fluid excavation at a location that will be adjacent to the future waterproof wall to be produced, an element is put in place tubular 4 similar to that of FIG. 2 at the bottom of the trench by orienting it substantially perpendicular to the future sealed wall, the excavating fluid is hardened or we replace it with a curable grout and we leave take to form the bar 11 (Figure 3a).

The actual waterproof wall is then produced, in making sure that when excavating the trench in which the waterproof wall will be molded, the tool used to cut the bar 11 and destroy the sealed end 7 of the tubular element, facing the sealed wall. After pouring concrete and hardening, the remaining extreme part of the element tubular, facing the wall, is embedded in the concrete (Figure 3b). We then excavate, under fluid excavation 2, a trench 12 on the side of the other end to the tubular member, making sure that the tool used to cut the hardened grout from the bar 11 and eliminate the other sealed end 7 of the tubular element. Then we come to fill the trench 12 permeable medium 13 (gravel, for example) (figure 1d). An excavation 20 is then carried out on the other side of the sealed wall 1 to a depth greater than that where is the tubular element, then we puncture the wall watertight, thus exposed, facing the tubular element 4, to create a passage 21 communicating the element tubular with excavation 20. It suffices, finally, to deflate balloon 9 to establish permeability through Wall.

Note that when excavation 20 is located between two watertight walls (case for example where a raft must be run between two or more watertight walls), it may need to do similar work to the one just described in the other watertight wall and to connect the passages 21 by a conduit, in order to allow groundwater to pass through the curtain of watertight walls.

It goes without saying that the embodiments described do not are just examples and could be changed, in particular by substitution of technical equivalents, without to go beyond the scope of the invention.

Claims (12)

1. A device for creating permeability to water in a watertight wall buried in the ground, comprising said wall (1) buried in the ground, a tubular element (4) for passing water through the wall, and closure means (9) operable from the surface of the ground for either closing or opening the passage formed by said tubular element.
2. A device according to claim 1, characterized in that it further includes a trench filled with permeable material into which one end of the tubular element discharges.
3. A device according to claim 1 or claim 2, characterized in that the tubular element is centered relative to the watertight wall and embedded therein.
4. A device according to claim 1 or claim 2, characterized in that the tubular element is eccentric relative to the watertight wall and buried in an element molded in the soil near the wall.
5. A device according to claim 1, characterized in that the closure means include an inflatable balloon.
6. A device according to any of claims 1 to 5, characterized in that the tubular element further includes a valve allowing the water to flow in only one direction.
7. A method of producing a device as defined in claim 1 or claim 3, characterized in that it includes producing an excavation (3), under excavation fluid (2), that transversely intersects the wall (1), and positioning in said excavation a tubular element (4) having a durable central tubular part (5) made from a relatively strong material, closed tubular end parts (7) adapted to be eliminated and made of a relatively fragile material, and means (9) for temporarily closing said central part adapted to be operated from the surface by control means (10), said tubular element extending transversely to the watertight wall (1) with the end parts adapted to be eliminated projecting relative to the wall, and then, after hardening the excavation fluid or replacing it with a hardenable slurry (11) and hardening thereof, eliminating the closed end parts adapted to be eliminated of the tubular element, and finally opening the closure means at the required time to create the permeability.
8. A method according to claim 7, characterized in that it includes a trench filled with permeable material into which discharges one end of the tubular element after elimination of the end parts adapted to be eliminated.
9. A method according to claim 7, characterized in that at least one of the end parts is eliminated by excavating under an excavation fluid a trench in vertical alignment with the end part to be eliminated with the aid of an excavation tool that intersects the fluid or hardened slurry and destroys said end parts adapted to be eliminated, and said trench is then filled with a permeable material to serve as a water collector or distributor trench.
10. A method of producing a device as defined in claim 1 or claim 4, useful if the watertight wall is made from a high mechanical strength material and delimits a raft foundation or a ditch, characterized in that it consists in: (a) producing, under excavation fluid, an excavation (3) adjacent and perpendicular to the watertight wall to be produced, (b) placing therein a tubular element (4) having a durable central tubular part (5) made from a relatively strong material, closed tubular end parts (7) adapted to be eliminated and made from a relatively fragile material, and closure means (9) for temporarily closing said central part and adapted to be operated from the surface by control means (10), hardening the excavation fluid or substituting to it a hardenable slurry and hardening it, so as to form a hardened slurry bar (11) including the tubular element, then (c) producing with an excavation tool the trench in which the watertight wall (1) will be molded so that the excavation tool intersects the bar previously produced and destroys the end part adapted to be eliminated of the tubular element facing toward the wall, (d) pouring concrete into the trench so that the end of the tubular element adjacent the wall is embedded in the concrete after it sets, (e) excavating the land (20) on the opposite side of the watertight wall to the bar to a level lower than that of the tubular element, (f) producing an excavation (12) at the opposite end of the bar to the watertight wall so that the excavation tool intersects said bar and destroys the other end part of the tubular element adapted to be eliminated, (g) piercing the watertight wall from the side of the wall exposed in step (e) and at the location of the tubular element to establish a passage (21) extending the opening of the tubular element through the watertight wall, and finally (h) opening the closure means (9) at the required time to create the permeability; steps (e) to (h) can be effected in an order different from that given.
11. A method according to claim 10, characterized in that the excavation produced in step (f) is then filled with permeable material.
12. An installation comprising two watertight walls each comprising a device as defined in any of claims 1 to 6, characterized in that the tubular elements of the devices are linked by a pipe.

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