FR2607534A1 - Method and device for using a concrete coating sprayed onto a damp wall - Google Patents

Abstract

The subject of the present invention is a method for producing a coating by spraying concrete onto a damp wall 1, characterised in that : a) draining membranes 2 are fixed against the said wall 1 in juxtaposition, which membranes comprise juxtaposed cells 2a which enable the run-off water to trickle down to the bottom part of the wall where it is drained off; b) screens 6 are fixed over the said draining membranes 2, are juxtaposed and are assembled to each other by means of sealing strips; c) assemblies are then fixed over the said screens 6, which assemblies are formed of panels of wire netting 10 and of welded wire mesh 11 superimposed by means of spacers 9 which keep the netting/mesh assemblies away from the said screens 6/18 and parallel to the latter and the concrete 12 is sprayed over onto the said screens 6 through the netting 10 and the mesh 11 in successive passes and they are covered until the desired coating thickness is obtained. Application in the repair of tunnels, retaining walls, embankment reservoirs, etc.

Description

DESCRIPTION
Method and device for the implementation of a sprayed concrete coating on a wet wall.

 The present invention relates to a method and a device for the implementation of a concrete coating sprayed on a wet wall.

 The technical sector of the invention is that of building and public works.

 As part of the rehabilitation of the lining of masonry structures such as retaining walls of a ground generating a flow of diffuse waters, earthworks tanks, tunnels etc. ... we sometimes see that the existing coating consists of masonry deformed by the pushes of the ground and by insufficient drainage.

In the case in particular of the repair of a tunnel, we are currently proceeding as follows
- Deep grooves are made to embed metal support hangers and the said hangers are coated with shotcrete.

 This phase is carried out by alternating studs so as not to jeopardize the stability of the section concerned.

 - The intervals between the curved rings are cleaned to obtain a sound surface and the said intervals are filled with sprayed concrete so as to obtain an approximately regular surface at about 0.40 m. behind the final facing.

- A polyvinyl chloride waterproofing membrane is put in place over the entire surface and the water is captured at the bottom of the vault for their evacuation;
- And the final coating is carried out by the use of cased concrete.

 On the other hand, it is sometimes also found that although the existing coating consists of masonry in good condition, the joints allow a large amount of infiltration water to be assimilated to rain, which in winter forms ice stalactites with all the risks that this entails.

 The protection of the coating of such works is therefore necessary.

 The objective of the present invention is to apply a technique different from that currently used by eliminating the formwork of facing concrete.

 Given that such work involves the installation of sealing screens constituted by smooth membranes or plates, the problem to be solved is that of the attachment of the concrete for the implementation of the coating.

This objective is achieved and the problem solved by the method according to the invention for producing a sprayed concrete coating covering a wet wall, which is essentially characterized by the following operations
a) - is fixed against said wall by juxtaposing draining membranes comprising juxtaposed cells, which promote the flow of runoff water to the lower part of the wall where it is discharged;
b) - screens above said draining membranes are fixed which are juxtaposed and which are assembled to each other by means of sealing strips covering their peripheral edges;
c) - then fixed, above said screens, assemblies formed of mesh plates and welded mesh superimposed by means of spacers which keep the mesh / mesh assemblies away from said screens and parallel to them this;
d) - and the concrete is projected onto said screens through the grating and the trellis by successive passes and they are covered until the desired coating thickness is obtained.

The device for implementing this process is characterized in that it essentially comprises
a) - several juxtaposed draining membranes fixed to said wall, which membranes comprise juxtaposed cells which promote the flow of runoff water to the lower part of the wall where it is discharged;
b) - juxtaposed screens fixed above said draining membranes, which screens are assembled to each other by means of sealing strips covering their peripheral edges;
c) - and above said screens, assemblies formed by superimposed mesh and welded mesh plates, fixed by means of spacers arranged between said screens and said assemblies, the mesh constituting a transient box during spraying concrete.

 The strength of the sprayed concrete against a membrane which offers no adhesion is thus obtained by the combination of spacers / mesh / welded mesh in which combination the spacer determines the first thickness of concrete to be sprayed, the mesh constitutes a transitional formwork at the first projection of concrete and the welded mesh, on the one hand, maintains the mesh during the first projection and on the other hand constitutes the reinforcement of the sprayed concrete covering.

 Of course, the thickness of concrete can be reduced or increased depending on the constraints to which the coating is subjected.

 This process is thus applicable for the repair or protection of existing linings of tunnels, retaining walls of oozing grounds, linings for earthworks tanks or other masonry constructions with wet walls.

Other advantages and characteristics of the invention will emerge further on reading the following description of the process and the device and their variants with reference to the appended drawing in which:
- Figures 1 to 5 are cross sections which illustrate the different stages of the process applied for the refection of an existing coating as well as the equipment used for the implementation of said process;
- Figures 6 to 10 are cross sections illustrating the different stages of the process applied for the protection of an existing coating as well as the equipment used for the implementation of this process.

 We first refer to Figures 1 to 5.

 For repairing the lining of a tunnel, for example, and prior to the specific operations of the process according to the invention, deep grooves are used, as is already the practice, to embed supporting metal hangers and the said hangers are coated with shotcrete. .

 The intervals between the hangers are then cleaned in order to obtain a healthy surface and these intervals are filled with sprayed concrete so as to produce an approximately regular surface at around 0.40 m. of the final facing.

 It will be noted that this surface can be constituted by natural rock which is optionally leveled to improve the facing of the surface to be treated.

These preliminary works having been carried out, the procedure according to the invention is as follows
- The wet wall 1 is covered (FIG. 1) with rectangular draining membranes 2 which are juxtaposed to interest the entire wall to be treated. These membranes are made of plastic, for example polyvinyl chloride and have cells 2a, for example of a trapezoidal cross section, which cells are juxtaposed between them and promote the flow of runoff water to the bottom of the wall. where it is discharged.

 - Said draining membranes 2 are fixed to the wall 1 by anchoring means, for example nails 3 which pass through the membranes 2, which nails are for example anchored in the wall by powder cartridges by means of an apparatus existing under the name "Spit". The nails 3 are distributed over the surface of the membranes.

 - Then have on said membranes 2 (Figure 2) support plates 4 of polyvinyl chloride preferably a circular shape and a diameter of 100 mm. that anchored in the wall 1 through the membranes 2 by means of nails 5 of the same type as those referenced 3 above and distributed over the surface of the membranes 2 for example at the rate of four support plates 4 per square meter.

 - Next, above said draining membranes 2 and support plates 4 are rectangular sheets of polyvinyl chloride 6 which are assembled together by means of covering strips and the sheets 6 are fixed to support plates 4 for example by hot air welding.

 The sheets 6 preferably have a thickness of 15/10 of a millimeter and form, after being assembled together, a waterproof membrane for runoff water.

 - Then fixed by hot air welding on the sheets 6 and to the right of the support plates 4 (Figure 3) other plates called fixing plates 7 which, like the support plates 4 are made of polyvinyl chloride d '' a circular shape with a diameter of 100 mm. These fixing plates have anchored in their central part a fastening wire 8. This wire is folded at 8a to form a U of elongated shape and is fixed to the plate by its folded part 8a. The two strands of the wire 8b / 8c extend substantially perpendicularly to the surface 7a of the fixing plate 7.

 Tubular spacers 9 placed around said strands 8b / 8c of wire 8 are supported on said fixing plates 7. These spacers 9 are for example made of hard polyvinyl chloride and are shorter than strands 8b / 8c of wire 8 to allow ligatures to be made later.

 - Then applied to said spacers 9 (FIG. 4) assemblies formed by rectangular mesh plates 10 called "chicken mesh" associated with welded mesh plates 11.

The mesh 10 and welded mesh 11 plates are superimposed and the mesh 10 is preferably placed against said spacers 9. Said sets 10/11 are juxtaposed to cover said waterproof membrane and are fixed to the fixing plates 7 by means of the strands 8b / 8c of the wires 8 which are passed through the mesh of the mesh and the trellis and are bent on the side of the trellis there to form ligatures.

 Preferably the mesh of the mesh is 25 mm. but can however be included in the range of 15 to 50 mm. as a function of the granulometry of the aggregates composing the concrete.

 The mesh of the welded mesh is for example 100 x 200 mm.

with rods with a diameter of 6 mm. or 5.5 mm.

 - Finally, the concrete is sprayed (Figure 5) onto the membrane formed by the polyvinyl chloride sheets 6 through the mesh 10 and the mesh 11 by successive passes of four to five centimeters in thickness and covered up to 'to obtain the desired coating thickness 12. For example, the concrete is dosed at 450 kg of cement and the coating thickness is 40 cms.

 Referring now to Figures 6 to 10 of the drawing which illustrate the different phases of the process according to the invention to protect an existing coating and the device for the implementation of this process.

This work applies more particularly to an existing coating consisting of masonry in good condition but whose joints allow a large amount of infiltration water to pass. The book
resulting from the method according to the invention and from the device for its implementation
implemented has the effect of avoiding, during the winter period,
the formation of ice stalactites by creating in front of the wet wall
a coating with thermal insulation.

According to this process,
- the wet wall 13 (FIG. 6) is covered with membranes
draining rectangular 14 which is juxtaposed to cover the
wall to be treated. These membranes are of the type of those 2 already described
with reference to FIG. 1 and comprise cells 14a
juxtaposed, which cells favor the flow of water
infiltration at the lower part of the wall 13 where it is
evacuated.

- The membranes 14 are fixed to the wall 1 by means of nails
15 which pass through the membrane, which nails are of the type of those previously described and marked with the reference 3. The nails 15 are
distributed over the surface of the membranes.

- Then anchors in the wall 13 (Figure 7) of the sockets
threaded 16 which is placed through said membranes 14 of the same
way that the nails 15 by means of the apparatus known as
the designation "Spit", which sockets 16 are distributed over the
area of membranes at the rate of one unit per square meter in feet
straight and two units per square meter-vaulted in the case of works
executed on a tunnel.

 The internal diameter of these sockets is for example 8 mm.

 - Then, in the sockets 16, threaded rods 17, for example made of stainless steel about fifteen centimeters in length, are screwed, which rods extend orthogonally to the wall 13.

 - Then there are, above said membranes 14, foam plates 18 having for example a thickness of 25 mm. Preferably polyethylene foam sheets are used with the aim of ensuring on the one hand sealing and on the other hand thermal protection.

 This implementation is done by simple manual pressure so that the threaded rods 17 pending through the foam.

 - Said foam plates are placed against the draining membranes 14.

 Cover strips ensure the connection of the plates 18 to each other.

 - Then put around each threaded rod 17, a putty 19 (Figure 8) to restore the seal to the right of the rods 17 and the foam plates 18 are fixed by means of nuts 20 screwed on the rods 17 and washers 21, for example in galvanized steel, brought into contact with the putty 19. The tightening of the nuts 20 ensures the holding of the foam plates 18.

 - Then positioned on each of the threaded rods 17 (Figure 9), a second nut 22 forming a spacer and placed in contact with said nuts 22 a first clamping plate 23 having for example as dimension 200 x 30 x 5 mm.

 - Then applied against the clamping plates 23 of the assemblies formed by rectangular mesh plates 24, associated with welded mesh plates 25, which plates 24/25 are superimposed, the mesh 24 being brought into contact with the clamping plates 23 Said assemblies 24/25 are juxtaposed to cover the foam plates 18 and are made up of components such as those 10/11 previously described with reference to FIG. 4.

 - Then put on each rod 17, a second clamping plate 26 identical to the plate 23 and we screw on the rod 17 a nut 27 which is pressed against said clamping plate 26 to fix the mesh assemblies 24 / trellis 25.

 - Finally, we spray dry (Figure 10) the concrete 28 on said polyethylene foam plates 18, through the mesh 24 and the mesh 25 in two successive passes for mechanical protection of the assembly and over a total thickness d 'about six to seven centimeters for example, so as to sufficiently coat the welded mesh 25 and the nuts 27.

 Depending on the purpose, the same process can be adopted by using a thicker polyethylene foam to increase thermal protection in the case of lower temperatures, or by increasing the thickness of the sprayed concrete for reinforcement of the coating.

 The innovation of the process lies in the technique used to hold concrete sprayed against a membrane: plastic film or sheets of insulating foam, which does not offer any adhesion, a problem which was resolved by placing it in front said membrane of a mesh associated with a welded mesh.

 Of course, without departing from the scope of the invention, the parts which have just been described by way of example may be replaced by a person skilled in the art by equivalent parts fulfilling the same function. Thus the method according to the invention and the devices for its implementation can have various applications for repairing or protecting tunnels, retaining walls, earthworks tanks or the like ... As is conceivable, the thickness of the sprayed concrete can be reduced or increased according to the constraints to which the coating is subjected.

Claims (11)

 1. Method for manufacturing a coating by shotcrete covering a wet wall (1/13), characterized by the following operations  a) - is fixed against said wall (1/13) by juxtaposing draining membranes (2/14) comprising cells (2a / 14a) juxtaposed, which promote the flow 'of runoff water to the lower part of the wall where it is evacuated;  b) - screens (6/18) are fixed above said draining membranes (2/14) which are juxtaposed and which are assembled to each other by means of sealing strips covering their peripheral edges;  c) - then fixed above said screens (6/18) assemblies formed of mesh plates (10/24) and welded mesh (11/25) superimposed by means of spacers (9 / 22) which keep the mesh / lattice assemblies away from said screens  (6/18) and parallel to these;  - And the concrete (12/28) is projected onto said screens (6/18) through the mesh (10/24 and the trellis (11/25) by successive passes and they are covered until the thickness of desired coating.  2. Method according to claim 1, characterized by the following operations  a) - said wall (1) is covered with draining membranes  (2) that are juxtaposed, which include juxtaposed cells  (2a) which promote the flow of runoff water to the lower part of the wall (1) where it is discharged and said membranes (2) are fixed to said wall (1) by anchoring means (3) distributed over the surface of the membranes (2);  b) - Then, on said membranes (2), there are support plates which are anchored in the wall (1) through the membranes.  (2) which support plates (4) are distributed over the surface of the membranes (2);  c) - plastic sheets are then placed above the draining membranes (2) and said support plates (4)  (6) which are assembled together by means of covering strips and said sheets (6) are fixed on said support plates (4);  d) - then fixed on the sheets (6) and in line with said support plates (4) fixing plates (7) equipped with a fastening wire (8) anchored in their central part and extending substantially perpendicular to said fixing plates (7);  e) - there are then arranged around the attachment wires (8) fixing plates (7), tubular spacers (9) supported on said plates (7) and such that the attachment wires (8 ) extend beyond the free end of the tubular spacers (9) ;;  f) - the mesh (10) associated with the welded mesh (11) is then applied to the said spacers (9) and the mesh / lattice assembly is fixed by means of the attachment wires (8);  g) - and the concrete (12) is projected onto said plastic sheets (6) through the mesh (10) and the trellis (11) by successive passes and they are covered until the desired coating thickness is obtained .  3. Method according to claim 1, characterized by the following operations  a) - said wall (13) is covered by draining membranes (14) which are juxtaposed which comprise juxtaposed cells (14a) which promote the flow of runoff water to the lower part of the wall ( 13) where it is discharged and said membranes (14) are fixed to said wall (13) by anchoring means (15) distributed over the surface of the membranes (14);  b) - then anchored in the wall (13) threaded sleeves (16) which are placed through said membranes (14) and which are distributed over the surface of the membranes;  c) - then screwed into said sockets (16) threaded rods, which extend orthogonally to the wall (13);  d) - there are then placed above the membranes (14) foam plates (18) which are pierced by the threaded rods (17) and the said plates (18) are placed against the draining membranes (14) and they are assembled by means of covering strips;  e) - the foam plates (18) are fixed by means of nuts (20) screwed onto said threaded rods (17) and of intermediate washers (21) bearing on said plates (18) by means of a seal (19).  g.- and the concrete (28) is sprayed onto said foam plates (18) through the grating (24) and the trellis (25) by successive passes and they are covered until the desired coating thickness is obtained.  second nut (22) forming a spacer and the mesh (24) is fixed to the threaded rods (17) associated with the welded mesh (25) by means of two clamping plates (23/26) located on either side of the mesh assemblies (24) / trellis (25) and a locking nut (27);  f) - one positions on each of the threaded rods (17) a  4.- Device for the implementation of a sprayed concrete coating covering a wet wall (1/13), characterized in that it comprises  a) - juxtaposed draining membranes (2/14) fixed to said wall (1/13), which membranes (2/14) include juxtaposed cells (2a / 14a) which promote the flow of runoff water up to 'at the lower part of the wall (1 / 131oh it is evacuated;  b) - juxtaposed screens (6/18) fixed above said draining membranes (2/14), which screens are assembled to each other by means of sealing strips covering their peripheral edges;  c) - and above said screens (6/18) assemblies formed by mesh (10/24) and welded mesh (11/25) plates superposed fixed by means of spacers (9 / 22) disposed between said screens (6/18) and said assemblies, the grid (10/24) constituting a transient formwork during the projection of the concrete (12/28);  5. Device according to claim 4, characterized in that it further comprises  a) - a plurality of support plates (4) anchored in the wall (1) through said draining membranes (2), which support plates (4) are distributed over the surface of the membranes (2);  b) - plastic sheets (6) assembled together by means of covering strips, which sheets (6) come to cover the membranes (2) and said support plates (4) and are fixed to said plates (4) ;  c) - a plurality of fixing plates (7) fixed to said plastic sheets (6) and in line with said support plates (4), which fixing plates (7) comprise a fastening wire (8) anchored in the central part and extending substantially perpendicular to said fixing plates (7);  d) - tubular spacers (9) which surround the attachment wires (8) of the fixing plates (7), which spacers (9) are shorter than the attachment wires (8) and are supported on said means plates (7);  e) - and assemblies formed by mesh plates (10) and welded mesh (11) superimposed fixed against said tubular spacers (9) by means of attachment wires (8).  6. Device according to claim 5, characterized in that the support plates 4 and the fixing plates (7) are made of plastic and are fixed to said sheets (6) by hot air welding.  7. Device according to claim 5, characterized in that the fixing plates (7) comprise two strands of tie wire (8b / 8c) anchored in the thickness of the plates.  8. Device according to claim 4, characterized in that it further comprises  a) - a plurality of threaded bushings (16) anchored in the wall (13) and corresponding to orifices made in said membranes (14), which bushings (16) are distributed over the surface of the membranes (14);  b) - threaded rods (17) screwed into said sockets (16), which rods extend orthogonally to the wall (13);  c) - foam plates (18) disposed against the draining membranes (14), which plates (18) are traversed by said threaded rods (17) and are fixed by means of nuts (20) screwed onto the rods (17 ) and of intermediate washers (21) bearing on said plates (18) by means of a seal (19) which plates (18) are joined to each other by cover strips; ;  d) - a second nut (22) screwed onto each of the threaded rods (17) and forming a spacer;  e) - and of several assemblies formed by mesh (24) and welded mesh (25) plates superposed fixed to the threaded rods (17) by means of two clamping plates (23/26) located on either side mesh (24) / mesh (25) and a locking nut (27) assemblies.  9. Device according to any one of claims 5 or 8, characterized in that the dimensions of the mesh of the mesh (10) are within the range of 15 to 50 mm. preferably 25 mm.  10. Device according to claim 9, characterized in that the seals (19) located between the foam plates (18) and the washers (21) consist of putty.  11. Device according to claim 9, characterized in that said plates (18) are made of polyethylene foam.