FR2755986A1 - DEVICE AND METHODS FOR CREATING PERMEABILITY IN A WATERPROOF 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.

  There is often a need to create one or more watertight walls in the ground, for example to protect an underground site against floods that could be caused by the surrounding aquifer. Once the site is completed, the watertight walls remain in place and obstruct the natural circulation of groundwater, which can have significant drawbacks. In particular, a rise in the level of the aquifer can occur, which results in the exertion of a considerable thrust on the watertight wall (s), which can cause damage to the wall itself and also cause infiltration into structures.

neighbors.

  To date, to the knowledge of the Applicant, there is no method or system making it possible to easily create a permeability in a sealed wall in the ground. Until now, it was necessary to resort to painstaking excavation work and to perforate or destroy locally 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 a method making it possible to easily create, at the desired time, a localized permeability in a wall

waterproof in the ground.

  More specifically, the invention relates to a device for creating a water permeability in a sealed wall in the ground, comprising a tubular element for the passage of water through the wall, characterized in that it comprises , in addition, means that can be actuated from the surface of the ground, making it possible to close and then release the

light of said element.

  The element can be centered relative to the sealed wall and, therefore, embedded in said wall, or alternatively, be offset relative 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 producing such a device. A first method for producing such a device, useful when the watertight wall is made of a material of low mechanical resistance, such as a curable grout, is characterized in that it comprises carrying out an excavation, under fluid excavation, coming to cut the wall transversely with positioning in said excavation of a tubular element comprising a perennial central tubular part made of a relatively resistant material, closed tubular end parts which can be eliminated in a relatively fragile material, and a means temporarily closing said actuable central part from the surface by a control means, said tubular element extending transversely to the sealed wall with the removable end portions projecting with respect to the wall, then, after hardening of the excavating fluid or replacement thereof by a curable grout and hardening thereof, to remove p extreme closed parts eliminable from the tubular element and finally to bring the closure means in the open position

  at the desired time for the creation of permeability.

  Preferably, there is also produced at least one trench filled with permeable material into which opens one of the ends 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 carried out in excavation under excavating fluid, a trench in line with the extreme part to be eliminated using a tool excavation which intersects the hardened fluid or grout and destroys said eliminable end portions, said trench then being filled with a permeable material, so as to act as a collecting trench

or water dispenser.

  A second method for producing such a device, useful in particular when the watertight wall is made of a material of high mechanical strength, such as reinforced concrete or not, and delimits a raft or a pit, is characterized in that it consists : (a) to carry out, under excavation fluid, an excavation adjacent to and perpendicular to the watertight wall to be produced, (b) to place therein a tubular element comprising a perennial central tubular part made of a relatively material resistant, closed tubular end parts which can be removed from a relatively fragile material, and means temporarily closing said central part and which can be actuated from the surface by a control means, to harden the excavating fluid or to replace it with a curable grout and hardening the latter, so as to form a bar in hardened grout including the tubular element, then (c) to be produced with an excavation tool the trench where the watertight wall will be molded, making sure to cut the previously produced bar with the excavation tool and to destroy the removable end portion of the tubular element facing the wall, (d) pouring the concrete into the trench with the result that the end of the tubular element, adjacent to the wall, is trapped in the concrete after it has taken, (e) to excavate the ground on the side of the watertight wall opposite the bar up to a level lower than that of the tubular element, (f) to carry out, at the end of the bar opposite the sealed wall, an excavation by making sure to intersect with the excavation tool said bar and destroy the other removable end portion of the tubular element, (g) piercing the sealed wall, from the side of the wall released in step (e), at the place where the element is located tubular, to establish a passage extending the l light of the tubular element through the sealed wall, and finally (h) bringing the sealing means into the open position at the desired time for the creation of the permeability. It should be noted that the order of execution of steps (e) to (h) is not critical and could be different from that indicated. For example, step (e) could follow step (f) rather than precede it, and step (h) could be performed at an earlier stage. Preferably, the excavation carried out in step (f) is

  then filled with permeable material.

  The excavation in which the tubular element is positioned may have any horizontal section, for example rectangular or circular. An excavation of rectangular section can be carried out using a bucket type excavator. A circular excavation can

be produced by a drill.

  The perennial central part of the tubular element is made of a relatively resistant material (for example metal), while the removable end parts which are closed can be made of a relatively fragile material (for example

plastic example).

  The closure means may consist of an inflatable element, such as a balloon, which can be inflated and deflated from the surface of the ground. 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 la to ld are schematic plan views illustrating the embodiment, according to the invention, of a system

  creating permeability in a tight wall.

  Figure le is a cross-sectional view along the

line X-X of figure ld.

  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 vertical section (Figure 3e) illustrating a variant of the system of the invention and its

production.

  The general reference 1 designates a sealed wall produced, for example, by pouring into a trench of a curable grout. At the location of the wall 1 desired for the implantation of the system, an excavation 3 is made in the conventional manner, under excavation fluid 2, across the wall by coming to intersect the latter. The depth of the excavation is substantially equal to that of the wall, although this is not essential (Figure la). We then descend into the trench, to the desired depth (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 in FIG. 2, comprises a central part 5, for example of metal, in which is threaded, in a centered manner, a duct 6, closed at its ends by lids 7, for example made of plastic, of length greater 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 suitable bores provided on the central part and the conduit 6 and extending to above the ground surface. The element finally comprises an inflatable balloon 9 located inside the duct 6, in line with the tube 8, which can be inflated or deflated from the ground surface by means of a small

pipe 10 running through pipe 8.

  After substitution of the excavating fluid by a hardening grout and setting of the latter, or after hardening of the excavating fluid itself, the tubular element 4 is embedded in the hardened mass of the bar 11 molded in the excavation 3 (figure lb). The lids 7, however, prevented the interior of the tubular element 2 from being invaded by the grout. We then excavate, under excavation fluid, two trenches 12 parallel to the wall 1 and perpendicular to the tubular element 4 by ensuring that the excavation tool used comes to cut the end parts of the bar 11 and destroy the sealed end portions of the conduit 6 of the tubular element 4 (Figure lc). Next, the excavating fluid filling the trenches 12 is replaced with an appropriate permeable material, such as gravel 13 or the like, to

  obtain the system shown in Figures 1d and.

  Then, when it is desired to create a permeability in the watertight wall, it is sufficient to deflate the balloon 9 to allow the underground water to pass from 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 provided with a membrane allowing water to pass selectively and stopping polluting agents or other undesirable substances. Also, if desired, one or both trenches 13 could be filled with reactive materials intended to selectively stop pollutants or other undesirable substances. Finally, still if desired, the tubular element could be provided with a valve, for example of the ball type, in order to allow the passage of water only in one direction, which is advantageous when the sealed wall

  delimits a volume of polluted or contaminated land.

  Figures 3a to 3e illustrate the embodiment of a variant of the system according to the invention in which the tubular element, instead of being centered relative to the wall, is eccentric on one side thereof. This variant is useful in particular when the waterproof wall is made of concrete,

  armed or not, and delimits a raft or a pit.

  Indeed, in this case there, it is not possible to easily produce a bar through the sealed wall and we must therefore proceed differently, for example as follows: We start by carrying out the excavation 3 under excavation fluid at a place which will be adjacent to the future watertight wall to be produced, a tubular element 4 similar to that of FIG. 2 is placed at the bottom of the trench by orienting it substantially perpendicular to the future watertight wall, the fluid is hardened excavation or we substitute a curable grout and we leave

  take to form the bar 11 (Figure 3a).

  The waterproof wall proper is then produced, making sure that, during the excavation of the trench in which the waterproof wall will be molded, the excavation tool used comes to cut the bar 11 and destroy the sealed end 7 of the tubular element, facing the sealed wall. After pouring the concrete and hardening, the remaining end part of the tubular element, turned towards the wall, is embedded in the concrete (Figure 3b). Then excavate, under excavation fluid 2, a trench 12 on the side of the other end to the tubular element, ensuring that the excavation tool used comes to cut the hardened grout of the bar 11 and eliminate the other sealed end 7 of the tubular element. Then we just fill the trench 12 with a 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 the tubular element is located, then the sealed wall is perforated, thus exposed, facing the element tubular 4, to create a passage 21 communicating the tubular element with the excavation 20. Finally, it suffices to deflate the balloon 9 to establish permeability through

Wall.

  It should be noted that when the excavation 20 is between two watertight walls (case for example where a raft must be executed between two or more watertight walls), it may be necessary to carry out a work similar to that which has just been described in the other watertight wall and to connect the passages 21 by a conduit, in order to allow the underground water to pass through the curtain

watertight walls.

  It goes without saying that the embodiments described are only examples and that they could be modified, in particular by substitution of technical equivalents, without

  to go beyond the scope of the invention.

Claims (12)

  1. Device for creating water permeability in a sealed wall (1) in the ground, comprising a tubular element (4) for the passage of water through the wall, characterized in that it comprises , in addition, means (9) operable from the ground surface allowing   to shut off, then to release the light from said element.   2. Device according to claim 1, characterized in that it further comprises at least one trench filled with permeable material into which one of the   ends of the tubular element.   3. Device according to claim 1 or 2, characterized in that the tubular element is centered by   compared to the watertight wall and embedded in it.   4. Device according to claim 1 or 2, characterized in that the tubular element is eccentric relative to the sealed wall and embedded in a molded element in the soil next to the wall.   5. Device according to claim 1, characterized in that the sealing means comprise an inflatable balloon.   6. Device according to any one of claims   1 to 5, characterized in that the tubular element further comprises a valve allowing the passage of water only in one direction.   7. A method of making a device as defined in claim 1 or 3, characterized in that it comprises making an excavation (3), under excavation fluid (2), coming to cut the wall transversely (1) with positioning in said excavation of a tubular element (4) comprising a perennial central tubular part (5) of a relatively resistant material, closable tubular end portions which can be eliminated (7) of a relatively fragile material, and a means ( 9) temporarily closing said central portion which can be actuated from the surface by a control means (10), said tubular element extending transversely to the sealed wall (1) with the removable end portions projecting relative to the wall, then, after hardening of the excavating fluid or replacement thereof by a hardenable grout (11) and hardening of the latter, to eliminate the obturable end parts which can be removed from the element tu bular and finally to bring the closure means in the open position at the desired time for the creation of the permeability. 8. Method according to claim 7, characterized in that it comprises at least one trench filled with permeable material into which opens one of the ends of the tubular element after elimination of the eliminable end portions. 9. Method according to claim 7, characterized in that the elimination of at least one of the end parts is carried out by excavating under excavating fluid, a trench perpendicular to the end part to be eliminated using '' an excavation tool which cuts through the hardened fluid or grout and destroys said removable end portions, said trench then being filled with a permeable material, so as to act as a collecting trench or water dispenser.   10. A method of producing a device as defined in claim 1 or 4, useful when the watertight wall is made of a material of high mechanical resistance and delimits a raft or a pit, characterized in that it consists: ( a) to carry out, under excavation fluid, an excavation (3) adjacent to and perpendicular to the sealed wall to be produced, (b) to place therein, a tubular element (4) comprising a central tubular part perennial (5) made of a relatively resistant material, closable end tubular parts which can be eliminated (7) made of a relatively fragile material, and means (9) temporarily closing said central part and actuable from the surface by a control means (10), hardening the excavating fluid or replacing it with a curable grout and hardening the latter, so as to form a bar (11) in hardened grout including the tubular element, then (c) to be produced with one or the excavation trench o the watertight wall will be molded (1) by making sure to cut the previously produced bar with the excavation tool and destroying the eliminable end part of the tubular element facing the wall, ( d) pouring the concrete into the trench with the result that the end of the tubular element, adjacent to the wall, is caught in the concrete after it has taken hold, (e) excavating the ground (20) on the side of the waterproof wall opposite the bar to a level lower than that of the tubular element, (f) to carry out, at the end of the bar opposite to the waterproof wall, an excavation (12) by making so as to intersect with the excavation tool said bar and destroy the other end part which can be eliminated from the tubular element, (g) to pierce the sealed wall, starting from the side of the wall released in step ( e), where the tubular element is located, to establish ir a passage (21) extending the lumen of the tubular element through the sealed wall, and finally (h) bringing the closure means (9) to the open position at the desired time for the creation of the permeability steps ( e) to (h) can be performed in an order different from that mentioned.   11. Method according to claim 10, characterized in that the excavation carried out in step (f) is then filled with permeable material.   12. Installation comprising two watertight walls each comprising a device as defined in one   any one of claims 1 to 6, characterized in that   the tubular elements of the devices are connected between them by a conduct.