Method and device for the laying down of a geomembrane

Abstract

A method and a device for laying down and sealingly anchoring a waterproofing liner of a synthetic material, on a surface of a hydraulic work. The liner is fastened by a plurality of tensioning and anchoring assemblies, each including a lower and upper metal section bars configured with a raised part having side flat surfaces for sealingly clamping the liner, wherein the lower section bar has more anchoring holes at a plurality of axially spaced apart anchoring zones; the surface of the hydraulic work is previously marked by reference marks underlining the presence of possible obstacles such as reinforcement rods near the anchoring holes of the anchoring zones of the lower section bar; therefore the lower section bar is positioned by aligning the anchoring holes to the reference marks, anchoring the section bar to the hydraulic work by anchoring devices) at least one hole of the anchoring zones wherein there is no obstacle to the insertion of the anchoring devices in the hydraulic work. The waterproofing liner is laid down on the surface of the hydraulic work, and is sealingly anchored it between the lower section bars and the upper section bars of the tensioning assemblies.

Claims

1. A method for laying down and tensioning a waterproofing liner on a surface of a hydraulic work, such as, for example, a canal, a dam, a water basin, or a hydraulic tunnel, wherein the waterproofing liner is fastened, tensioned and made to sealingly adhere to the surface of the hydraulic work by sealingly clamping the waterproofing liner by a plurality of locking assemblies, wherein each locking assembly includes a lower metal section bar anchored to the surface of the hydraulic work, and an upper metal section bar that conforms to the lower section bar; and wherein the waterproofing liner is sealingly clamped between the lower section bar and the upper section bar; wherein said method includes the steps of a) configuring each lower section bar, or an additional elongated anchoring element, with a set of anchoring holes at a plurality of anchoring zones, in axially spaced apart positions; b) marking anchoring zones of the surface of the hydraulic work with a set of reference marks in positions corresponding to the positions of the anchoring holes of the anchoring zones of the lower section bar, or additional elongated anchoring element; c) perforating the surface of the hydraulic work at least one reference mark of the anchoring zones of the surface of the hydraulic work; d) positioning each lower section bar, or additional elongated anchoring element, aligning the set of the anchoring holes of each anchoring zone of the section bar with the perforations made at each anchoring zone of the surface of the hydraulic work; e) anchoring the lower section bar, or the additional elongated anchoring element to the hydraulic work, by anchoring devices passing through said anchoring holes aligned to the perforations made at the reference marks; and f) laying down, anchoring and tensioning the waterproofing liner, connecting the upper section bar to the lower section bar of each locking assembly, sealingly clamping the waterproofing liner between opposite slanted flat walls of the lower section bar and the upper section bar.

2. The method of claim 1, wherein the pitch between the anchoring holes in each set of anchoring holes, is less than a pitch between sets of the anchoring holes.

3. The method of claim 2, wherein each upper section bar is connected to the respective lower section bar by disengageable connecting members, inserted through connecting holes on said upper and lower section bars, wherein the pitch between connecting holes of the two section bars is less than the pitch between the anchoring zones of the sets of anchoring holes of the lower section bar, or additional elongated anchoring element.

4. The method according to claim 1, wherein, if the presence of an obstacle is detected at the time of perforation of the body of the hydraulic work at one reference mark of an anchoring zone of the hydraulic work, another perforation is made at another reference mark of the same anchoring zone.

5. The method according to claim 1, wherein the lower section bar is connected, for example welded, to the lower additional elongated anchoring element after the latter has been positioned and anchored to the surface of the hydraulic work.

6. The method according to claim 1, wherein the surface of the hydraulic work is marked with the reference marks making use of an auxiliary mask provided with reference holes arranged in positions corresponding to the positions of the anchoring holes of the lower section bar, or of the additional elongated anchoring element.

7. A locking assembly suitable for laying down and tensioning a waterproofing liner on a surface of a hydraulic work, wherein said locking assembly includes a lower metal section bar to be anchored to the surface of the hydraulic work; and an upper metal section bar that conforms to the lower section bar; wherein an elastically yieldable waterproofing liner is meant to be locked and tensioned by sealingly clamping the waterproofing liner between the lower section bar and the upper section bar; wherein: said locking assembly has, optionally, an additional elongated anchoring element underneath the lower section bar; said lower section bar, or said additional elongated anchoring element having anchoring zones, wherein each anchoring zone is configured with a set of anchoring holes to introduce anchoring devices into the body of the hydraulic work; and wherein said anchoring zones are spaced apart by a pitch in a longitudinal direction of each locking assembly.

8. The locking assembly of claim 7, wherein the space between the anchoring holes belonging to a set of anchoring holes is less than the pitch between two set of anchoring holes.

9. The locking assembly of claim 7, wherein the upper section bar is connected to the lower section bar by connecting members inserted through connecting holes of said upper and lower section bars, spaced apart in the longitudinal direction by a pitch that is less than the pitch between two sets of anchoring holes.

10. The locking assembly according to claim 7, wherein the thickness of the upper section bar is greater than the thickness of the lower section bar.

11. The locking assembly according to claim 7, wherein the lower section bar is provided with a threaded bush at each connecting hole.

12. The locking assembly according to claim 7, wherein the lower section bar and the upper section bar include opposite slanted lateral walls between which the waterproofing liner is clamped and tensioned.

13. The locking assembly of claim 12, wherein the lateral walls of the upper section bar have a slanting greater than the lateral walls of the lower section bar.

14. The locking assembly according to claim 7, wherein the lower section bar includes a raised central part and lateral wings provided with sets of anchoring holes, and wherein said raised central part of the lower section bar includes connecting holes for connection to the upper section bar.

15. The locking assembly according to claim 7, wherein the additional elongated anchoring element is mechanically connected to the lower section bar.

16. The locking assembly according to claim 7, wherein a raised part of the lower section bar, includes a set of anchoring holes for anchoring to the hydraulic work.

17. The locking assembly according to claim 7, including a drainage device for discharging the water accumulated between the waterproofing liner and the surface of the hydraulic work.

18. The locking assembly according to claim 7, wherein an impermeable cover strip is superimposed to the upper section bar.

19. A device for laying down and tensioning a waterproofing liner on a surface of a hydraulic work, wherein said device includes a plurality of locking assemblies that extend in a longitudinal direction for sealingly clamping and tensioning the waterproofing liner, each locking assembly being configured to include: a lower metal section bar to be anchored to the surface of the hydraulic work; and an upper metal section bar that conforms to the lower section bar; wherein an elastically yieldable waterproofing liner is meant to be locked and tensioned by sealingly clamping the waterproofing liner between the lower section bar and the upper section bar; wherein: said locking assembly has, optionally, an additional elongated anchoring element underneath the lower section bar; said lower section bar, or said additional elongated anchoring element having anchoring zones, wherein each anchoring zone is configured with a set of anchoring holes to introduce anchoring devices into the body of the hydraulic work; and wherein said anchoring zones are spaced apart by a pitch in a longitudinal direction of each locking assembly.

20. The device of claim 19, including at least one auxiliary mask provided with reference holes to mark the surface of the hydraulic work with a set of reference marks, in positions corresponding to the positions of the anchoring holes on the lower section bar or additional elongated anchoring element.

21. A waterproofing liner assembly for a surface of a hydraulic work, such as, for example, a canal, a dam, a water basin, or a hydraulic tunnel, wherein said waterproofing liner assembly includes a plurality of impermeable geomembrane sheets, and a plurality of devices fastened and made to adhere to the surface of the hydraulic work by: a plurality of locking assemblies that extend in a longitudinal direction for sealingly clamping and tensioning the waterproofing liner, each locking assembly being configured to include: a lower metal section bar to be anchored to the surface of the hydraulic work; and an upper metal section bar that conforms to the lower section bar; wherein an elastically yieldable waterproofing liner is meant to be locked and tensioned by sealingly clamping the waterproofing liner between the lower section bar and the upper section bar; wherein: said locking assembly has, optionally, an additional elongated anchoring element underneath the lower section bar; said lower section bar, or said additional elongated anchoring element having anchoring zones, wherein each anchoring zone is configured with a set of anchoring holes to introduce anchoring devices into the body of the hydraulic work; and wherein said anchoring zones are spaced apart by a pitch in a longitudinal direction of each locking assembly.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The invention shall be better understood and implemented by referring to the enclosed drawings showing no limitative examples:

[0037] FIG. 1 is a cross-sectioned view of a first example of a locking assembly according to the present invention, for sealingly clamping and tensioning a waterproofing liner on a surface of a hydraulic work to be waterproofed, in a locking zone between section bars, wherein two sheets of the waterproofing liner have overlapping edges.

[0038] FIG. 2 is a cross-sectioned view similar to FIG. 1 wherein a single sheet of the waterproofing liner is present in the clamping zone between the section bars.

[0039] FIG. 3 is a view from above, of the upper section bar of the locking assembly of FIG. 1 or 2.

[0040] FIG. 4 is a view from above, of the lower section bar of the locking assembly of FIG. 1 or 2.

[0041] FIG. 5 is a section in enlarged scale of lower and upper section bars of the locking assembly of FIG. 1 or 2.

[0042] FIG. 6 is a cross-section of a second example of a locking assembly according to the present invention, wherein the lower section bar is welded to an additional elongated anchoring element.

[0043] FIG. 7 is a view from above, of the sole lower section bar of the locking assembly of FIG. 6, without the additional elongated anchoring element.

[0044] FIG. 8 is a view from above, of the additional elongated anchoring element of the locking assembly of FIG. 6.

[0045] FIG. 9 is a cross-sectioned view of a third example of a locking assembly according to the present invention.

[0046] FIG. 10 is a view from above, of the upper section bar of the locking assembly of FIG. 9.

[0047] FIG. 11 is a view from above, of the lower section bar of the locking assembly of FIG. 9.

[0048] Figures from 12 to 15 are four views from above showing some phases of a method for laying down and tensioning a waterproofing liner on a surface of a hydraulic work.

DETAILED DESCRIPTION

[0049] With reference to the above figures, it is to be noted that similar elements, though belonging to different implementation examples, are indicated with a same reference number, for simplicity purposes.

[0050] By reference number 1 it is indicated a waterproofing liner for a big hydraulic work. The liner 1 comprises a plurality of geomembrane sheets 1a, 1b arranged one next to the other, wherein adjacent geomembrane sheets 1a, 1 b have edge portions reciprocally overlapping. A waterproofing liner, as known, comprises a plurality of membrane sheets elastically flexible, made of synthetic material, suitable for waterproofing a surface 2 of a hydraulic work. The hydraulic work can comprise, for example, a canal, a dam, a water basin, a hydraulic tunnel, and more.

[0051] Geomembrane sheets 1a, 1 b are blocked and made adhere to the surface 2 of a hydraulic work, whose body is indicated by 3. The waterproofing liner 1 is sealingly clamped and tensioned by means of a plurality of locking assemblies 4 configured for sealingly locking and tensioning the geomembrane sheets. The various locking assemblies 4 extend (for example in a canal or hydraulic tunnel) in a longitudinal direction and are intended to be positioned on the surface 2 along respective surface portions extended longitudinally (anchor strips) being parallel and at a certain distance from each other.

[0052] Each locking assembly 4 comprises a lower metal section bar 5 and an upper metal section bar 6, for example in stainless steel.

[0053] The lower section bar 5 is configured with a raised part having trapezoidal shape, comprising an upper wall 5a (for example flat) and two side opposite walls 5b (for example flat and inclined with respect to the upper wall 5a). Lower section bar 5 also comprises, in the example of FIGS. 1-5, two side wings 5c for the anchoring to the body 3 of the hydraulic work.

[0054] The upper section bar 6 conforms to the trapezoidal shape of the raised part of the lower section bar 5. In particular the upper section bar 6 comprises an upper part 6a (for example flat) and two sides opposite walls 6b (for example flat and inclined with respect to the upper wall 6a).

[0055] The side walls 6b can be more inclined than side walls 5b, in order to guarantee a compression action of the geomembrane between these side walls and thus improve the sealingly clamping.

[0056] By reference number 7 it is indicated a gasket (for example made of EPDM) arranged between the overlapped edges of the two sheets of geomembrane 1a, 1b and the upper wall 5a or 6a of lower section bars 5 and upper section bars 6. In the case shown in FIG. 1, the gasket 7 is arranged between the upper wall 6a of the upper section bar 6 and the edges of the geomembrane sheets 1a, 1b.

[0057] Lower and upper section bars 5 and 6 are connected among them through a set of connecting members 8, for example of screw type. Gasket 7 is used for the sealing near the connecting members 8. Assembly 4 can comprise more additional gaskets, one for each connecting member 8, or a single elongated gasket 7 applying to all connecting members 8.

[0058] Each connecting member 8, in these examples, is disengageably connected to a corresponding internally threaded bush 9 being fixed (for example by snap-fit coupling or welding) underneath the upper wall 5a of the lower section bar 5.

[0059] The lower section bar 5 is anchored to the hydraulic work through a plurality of anchoring devices 10 (for example of the prior art type) that deeply penetrate within the body of the hydraulic work, through anchoring holes 11 in correspondence of a plurality of anchoring zones 21.

[0060] By reference number 11 it is indicated the anchoring holes on the side wings 5c (in the example of FIGS. 1-5) for the passing through of anchoring devices 10; by reference numbers 12a and 12b the connecting holes on the upper walls 5a and 6a for the passing through of the connecting members 8; and by reference numbers 13 and 14 the opposed inclined flat surfaces, respectively of side walls 5b and 6b, between which the waterproofing liner 1 is compressed and clamped.

[0061] The anchoring holes 11 are distributed in such a way as to form various sets of anchoring holes in respect to the various anchoring zones 21 axially spaced apart in the longitudinal direction of the locking assembly 4. Each set of holes is formed by two or more anchoring holes 11 (by three holes 11 in the examples of FIGS. 1-5 and FIGS. 6-8, by two holes 11 in the example of FIGS. 9-11). The space between the anchoring holes 11 belonging to a same set of holes is relatively small, in particular is less than a pitch P (for example constant) between two sets of the anchoring holes 11. The space between the anchoring holes 11 belonging to a same set of holes is less than the axial space (in a longitudinal direction) between two anchoring holes 11 belonging to two different sets of holes, that is two different anchoring zones 21. The connecting holes 12a and 12b are spaced apart in the longitudinal direction by a pitch S (constant or not) that is less than the pitch P (constant or not) between two sets of anchoring holes 11. In this way it is possible to have a relatively high number of connecting holes 12a, 12b, in order to guarantee an effective and strong locking of the upper section bar 6 to the lower section bar 5 of each assembly 4, avoiding distortions of the upper section bar 6 caused by the stresses or external forces acting on the waterproofing liner.

[0062] In the examples here illustrated, connecting the holes 12a and 12b are spaced apart at a constant pitch S, while the sets of anchoring holes 11 are basically equal one another and are arranged in such a way that corresponding anchoring holes 11 having the same position in two sets of adjacent holes, are spaced apart at a constant pitch P. Pitch P of anchoring holes 11 is greater (for example greater of 30%, or greater of 40%, or greater of 50%) than pitch S of connecting holes 12.

[0063] The thickness of the upper section bar 6 is greater than the thickness of lower section bar 5. In particular the thickness of the upper section bar 6 is greater of at least 20% than the thickness of the lower section bar 5. In this case, the upper section bar 6 has an average thickness (constant) of 4-5 mm while lower section bar 5 has an average thickness (constant) of 2.5-3.5 mm. In this way the solidity of a locking assembly 4 is further improved as well as its resistance to stresses transmitted by waterproofing liner 1.

[0064] Finally by reference number 22 it is indicated an additional waterproof strip for sealing and protection (optional), put on the top of the upper section bar 6a; the waterproofing strip 22 consists, for example of a geomembrane strip welded on both sides to the geomembrane of liner 1; strip 22 extends all along the section bar 6a; strip 22, besides being water resistant, can be necessary in case of ice formation and in case the presence of section bars 5, 6 in stainless steel has to be hidden, in order to avoid thefts or vandalism.

[0065] The second example, shown in FIGS. 6-8, differs from the first one basically because in this case the locking assembly 4 comprises a flat additional elongated anchoring element 15 presenting anchoring holes 11 in a plurality of anchoring zones 21, as in the previous case. Therefore the additional elongated anchoring element 15 is clamped to the body 3 of the hydraulic work by means of anchoring devices 10, while the lower section bar 5, being in this case without anchor lateral wings 5c of the previous example, is connected to the additional elongated anchoring element 15, for example by welding lines 16, as in this example or through a specific welding.

[0066] The third example, shown in FIGS. 9-11, differs from the preceding examples because the holes 11 of the single anchoring zones 21, are arranged (in groups of two) on the raised part, in particular on the upper wall 5a of the lower section bar 5. In this case the anchoring devices 10 pass through the upper wall 5a.

[0067] According to the method of the present invention, on the surface 2 of the hydraulic work to be made waterproof, a plurality of anchor strips B will be located, being extended in a longitudinal direction (for example horizontal in case of canals and hydraulic tunnels, in particular vertical in case of dams), parallel and spaced apart among them; each locking assembly 4 will be arranged on a corresponding anchor strip of the surface 2; each locking assembly 4 will be provided with a plurality of anchoring zones 21, each one corresponding to a set of anchoring holes 11 (two or more); for each anchor strip B (associated to a corresponding locking assembly 4) a plurality of anchoring zones will be identified (indicated by reference 20 in FIGS. 12-15): each anchoring zone 20 will be associated a relative anchoring zone 21 on the locking assemblies 4, in other words a corresponding set of anchoring holes 11 formed by two or more holes for anchoring the lower section bars 5 to the body 3 of the hydraulic work.

[0068] Now, particularly referring to FIGS. 12-15 that show a part of an anchor strip B on which a corresponding locking assembly 4 will be arranged, a specific example will be illustrated of a method for laying down the waterproofing liner 1 on the surface 2 of the hydraulic work.

[0069] In a first phase (FIGS. 12 and 13) the surface 2 of the hydraulic work is marked by a series of reference marks 19 for each anchor strip B, in correspondence of a plurality of anchoring zones 20 distributed along each anchor strip B, according to axially spaced apart positions in the longitudinal direction of each locking assembly, in the same positions of anchoring holes 11 of lower section bar 5.

[0070] Such marking can be implemented in any way, for example making use of a mask 17 (for example in the form of a plate arranged lengthwise) that, as for lower section bars 5, presents a number of reference holes 18 to create (for example by spraying a paint) reference marks 19 on the surface 2 in the various anchoring zones 20. FIG. 12 shows the mask 17 positioned on the anchor strip B of the surface 2, while FIG. 13 shows the anchor strip after the marking with the reference marks 19 and after the removal of the mask 17.

[0071] Reference marks 19 are positioned in a way as to correspond to the positions of the anchoring holes 11 used to configure the lower section bar 5, or the lower additional elongated anchoring element 15.

[0072] In a second phase (FIG. 14) each lower section bar 5 (or additional elongated anchoring element 15) is positioned on each anchor strip of the surface 2 of the hydraulic work, aligning the anchoring holes 11 of each anchoring zone 21 on the lower section bar 5 or additional elongated anchoring element 15, to the reference marks 19 of each anchoring zone 20 of the surface 2.

[0073] The lower section bar 5 (or additional elongated anchoring element 15) is therefore anchored to the hydraulic work, using the anchoring holes 11 aligned to reference marks 19 in which position there is no obstacle to the insertion of anchoring devices 10.

[0074] In practise, it is possible to proceed perforating the body 3 of the hydraulic work in correspondence of a reference mark 19 in a first anchoring zone 20; if no obstacle is found during the perforation, once perforation is made, it is possible to proceed with a reference mark 19 of another anchoring zone 20; on the contrary, if an obstacle is found, the perforation of the body 3 of the hydraulic work will be made beside another reference mark 19 of the same anchoring zone 20; in this way it will be possible to use, for each anchoring zone 20, at least an anchoring hole 11 next to which there is no obstacle to the insertion of the anchoring device 10, being unlikely that, for each anchoring zone 20, there is not at least a marked position without obstacles.

[0075] Once holes in the various anchoring zones 20 along each anchor strip B have been made, it is possible to fasten the various lower section bars 5 (or additional elongated anchoring elements 15) to the body 3 of the hydraulic work, by matching holes 11 of the anchoring zones 21 of each lower section bar 5 or additional elongated anchoring element 15, to the holes made at the reference marks 19 of the anchoring zones 20 of each anchor strip.

[0076] After that, once fastened the various lower section bars 5 to the body 3 of the hydraulic work, in a third phase (FIG. 15), the waterproofing liner is laid down, anchored and tensioned connecting each upper profile 6 to the correspondent lower section bar 5, by sealingly clamping the waterproofing liner between the flat inclined surfaces 13 and 14 that are opposed of the lower section bar 5 and of the upper section bar 6.

[0077] The locking assembly 4 can comprise, in particular, a drainage device to make flow the water accumulated between the waterproofing liner 1 and the surface 2 of the hydraulic work. Such drainage device can however be configured; for example they can comprise an element suitable for creating a gap between the wings 5c of the lower section bar 5 and the surface 2 of the hydraulic work, with the wings of the section bar 5 being slightly raised with respect to the surface 2, in order to allow the passage of accumulated water. Such distance of the lower section bar 5 from the surface 2, can be implemented in various ways: for example it is possible to arrange a spacer (for example a lock washer), in particular in correspondence of one or more anchoring holes 11; it is also possible, for example, that the section bar is provided with at least one or more protrusions (for example an evident embossed of the iron sheet), in particular at least one or more anchoring holes 11; it is also possible, for example, to implement pass through openings (small holes) through the lower section bar 5 (in particular through the base of the walls 5a and 5b); it is also possible, for example, to fold the side wings 5c and obtain pass through openings (small holes) as in the previous example.