EP0521745B1 - Method for erecting and dismantling shuttering for walls poured on a reference surface and means for its application - Google Patents

Abstract

The invention relates to a method for erecting and dismantling the shuttering of walls (1) made from a cast material erected above a reference surface (2) especially with the aid of elements of sheeting (3), each comprising a shuttering face (4) and equipped with casters (31, 32) at their base. This method is characterised in that: - for the shuttering: . from the dismantled position of the shuttering, by tilting at least the base (29) of the shuttering face (4) of the sheeting (3) towards the wall (1) to be shuttered, thereby for this purpose revolving about an axis substantially defined by the bearing points (10) of the casters (31) on the reference surface, the lower edge (35) of the shuttering face (4) is brought to bear on the reference surface (2) then, . by continuing the tilting of at least the base (29) of the shuttering face of the sheeting (3) towards the wall (1) to be shuttered, but by revolving, for this purpose, about an axis substantially defined by the lower edge (35) of the shuttering face of the sheeting (3), the casters (31) are lifted off the reference surface and - for dismantling the shuttering, the operations are reversed. Application to the building industry and to shuttering equipment. <IMAGE>

Description

The invention relates to a formwork and formwork removal process for walls of cast material raised above a reference surface and to the means for implementing this method.

It applies in particular to the construction of walls and partitions of buildings.

To date, for formwork and formwork removal from walls, formwork is generally used (FR-A-1,277,437) each comprising a formwork face formed by one of the faces of a sheet metal which, on its opposite face, is provided with stiffeners arranged in directions perpendicular to each other in order to guarantee by its rigidity the geometric correction of the formwork wall.

The formwork face generally has a height substantially equal to the height of the wall to be poured and the widest possible width while remaining low enough to limit the weight of the formwork and, therefore, for each face of the wall to be formed, it is generally called upon several forms arranged in the extension of each other and assembled together by means ensuring the continuity of the formwork face.

These forms then have their shuttering faces placed vertically opposite and are braced with a distance between them corresponding to the thickness of the wall.

At at least one of their ends, they are provided with shuttering panels forming the vertical edges of the walls or at least ensuring that the cast material will not escape laterally.

In order to guarantee the verticality of their formwork faces, these forms are, by their stiffeners, associated with a structure offering the formwork, at a certain distance from the formwork face, at least one support point possibly adjustable on the reference surface.

In the case where the walls are poured in isolation from the horizontal walls connecting the upper edges of two successive walls, the structure is generally formed by triangular trusses provided at a suitable distance from a support on the reference surface (FR-A-1.277 .437).

• d'une part, à leur partie supérieure, par un platelage en une ou plusieurs parties présentant une face coffrante, formée par la face supérieure d'une tôle dont la face inférieure coopère avec des raidisseurs disposés selon deux directions perpendiculaires entre elles pour garantir la correction géométrique de la paroi et,
• d'autre part, près de leur base par des traverses réglables.

In the more general case where, on the contrary, simultaneously with the vertical walls, it is desired to pour the horizontal wall extending between the upper edges of said successive vertical walls such as the ceiling tile of the two walls of the same cell such as a room d 'a building, the forms are with their stiffened opposite faces arranged vertically with a distance between them corresponding to the distance between the vertical walls of the same cell and connected together:

• on the one hand, at their upper part, by a decking in one or more parts having a shuttering face, formed by the upper face of a sheet, the lower face of which cooperates with stiffeners arranged in two directions perpendicular to each other to guarantee the geometric correction of the wall and,
• on the other hand, near their base by adjustable crosspieces.

In this case, each branch thus associated with the other branch directly creates the structure offering the other branch the fulcrum guaranteeing its verticality.

The associated vertical and horizontal shuttering faces give the entire shuttering device an inverted U shape commonly known as a tunnel.

As regards the decking or at least one of its parts, it is known to associate it with a support structure on the reference surface giving it the shape of a table (FR-A-1.345.570 ).

It is also known to make the formwork part of the formwork inseparable from the formwork face of at least part of the decking.

In a known embodiment (FR-A-1,180,699) the decking, duly stiffened by itself in two perpendicular directions, is divided into at least two sections which join in joint planes parallel to the formwork and each section of adjoining decking a formwork with its formwork face associated with that of the formwork and with its transverse stiffeners articulated on the vertical stiffeners of the formwork so that, by deformation of the dihedral angle between the section of decking and the formwork, the fractions are succeeded in removing formwork generally called half-shells of the tunnel formwork device.

According to another known embodiment (FR-A-1,512,440), the decking is by itself at least locally stiffened only in a direction parallel to the formwork and, during formwork, to present the required flatness, rests freely on crosspieces associated with the stiffeners of the formwork.

To allow formwork, these support beams of the decking each consist of at least two sections articulated on the one hand between them under the middle part of the decking and, on the other hand, at one of their ends on the stiffeners of one of the forms.

The profiles of these crosspieces, commonly known as scissors, can be maneuvered so as to form between them an angle turning its concavity towards the decking thus depriving it at least locally of its transverse stiffeners so that it can under its own weight or by traction curving and thus ensuring the formwork of the horizontal wall but also from the top of the vertical walls by tilting a few degrees due to the reduction in spacing induced in the upper part of the tunnel by the operation of the scissors.

In these two tunnel embodiments, of course for the pouring of the horizontal walls, for example the closure panels provided for the formwork, the decks are on their banks equipped with slab stop panels of at least equal height to the thickness of these horizontal walls to prevent the cast material from escaping laterally.

Whatever type of panel used to complete the formwork, its base is also, in a second step, detached from the wall by action on the structure provided at the rear of the formwork.

If the reference surface makes it possible to correctly position the formwork in height and in verticality, on its own, it does not make it possible to determine the position of the base of the formwork face of the formwork in the plane of said reference surface.

To this end, reference marks are provided on the reference surface provided with vertical faces rising over a small height, each defining the position of the plane of one face of the wall to be erected and against which the bases of the formwork faces of the formwork can then be brought into abutment.

To facilitate the handling of these forms and the structures associated with them, the forms are currently equipped at their base with rollers, each turning generally freely around an axis perpendicular to the formwork face and carried by a yoke directly attached to the rear face of the shuttering sheet at a height such that the lower part of each caster is located at a level lower than the lower edge of the shuttering face when the latter is at least substantially vertical (FR-A-1,536,380).

The lower edge of the formwork face of the formwork can thus with play and therefore without rubbing on the reference surface allow the movement of the formwork in a direction parallel to itself.

The support by casters on the reference surface does not guarantee a rigorous position of the formwork in its plane nor its immobilization, to, for the formwork, give a correct support to the formwork their casters must be detached from the reference surface and, for this purpose, at the base of the formwork, cylinders with a vertical axis are also provided, the lower end of which is provided with a bearing pad on the reference surface.

Also, in the embodiments known to date, with a view to casting, the lower edge of the shuttering faces of the formwork is still lifted from the initial clearance increased by the height of separation of the rollers from the reference surface.

The corresponding gap requires the provision on the reference surface and / or on the formwork of means in order to prevent the cast material from escaping.

For this purpose, it is known to provide at the base of the formwork a removable panel for closing the aforementioned gap, but this panel, commonly known as under-rise, and its means of articulation on the formwork complicate the formwork and oblige on the site to perform additional maneuvers which has a negative impact on the cost.

Another known solution consists in producing positioning stops on the reference surface which extend over the entire length of the formwork and thus produce wall primers.

To make these primers at the same time as the walls and the ceiling slab of the lower level, it is necessary, in addition to the means associated with the formwork of the lower level, to provide angles for formwork of the primer and their clamping means in position. required which also increases the price of site equipment and the cost of construction.

In addition, the support of the formwork face of the formwork on such a primer is never perfect and on the formwork wall therefore appear flatness defects.

One of the results that the invention aims to obtain is a formwork-formwork process which ensures a perfect seal at the base of the formwork without the need to provide under-rises or primers of walls.

Another result which the invention aims to obtain is a sheet which is simple and easy to implement.

• pour le coffrage :
  • . depuis la position décoffrée, par basculement vers la paroi à coffrer d'au moins la base de la face coffrante de la banche, en tournant à cet effet autour d'un axe sensiblement défini par les points d'appui des roulettes sur la surface de référence, on amène le bord inférieur de la face coffrante en appui sur la surface de référence puis,
  • . en poursuivant le basculement vers la paroi à coffrer d'au moins la base de la face coffrante de la banche mais en tournant à cet effet autour d'un axe sensiblement défini par le bord inférieur de la face coffrante de la banche, on soulève les roulettes de la surface de référence et inversement,
• pour le décoffrage :
  • . depuis la position coffrée par basculement d'au moins la base de la face coffrante de la banche dans le sens de son écartement de la paroi coffrée, en tournant autour de l'axe sensiblement défini par le bord inférieur de la face coffrante, on amène les roulettes en appui sur la surface de référence et,
  • . en poursuivant le basculement dans le même sens mais en tournant alors autour de l'axe sensiblement défini par les points d'appui sur la surface de référence, on soulève le bord inférieur de la face coffrante de la surface de référence.

To this end, it relates to a process of the type mentioned above, in particular characterized in that:

• for formwork:
  • . from the stripped position, by tilting towards the wall to be shuttered at least the base of the shuttering face of the formwork, by turning for this purpose around an axis substantially defined by the bearing points of the rollers on the surface of reference, the lower edge of the shuttering face is brought to bear on the reference surface then,
  • . by continuing the tilting towards the wall to be shuttered of at least the base of the formwork face of the formwork but by turning for this purpose around an axis substantially defined by the lower edge of the formwork face of the formwork, the casters from the reference surface and vice versa,
• for formwork:
  • . from the formwork position by tilting at least the base of the formwork face of the formwork in the direction of its separation from the formwork wall, by turning around the axis substantially defined by the lower edge of the formwork face, the rollers resting on the reference surface and,
  • . by continuing the tilting in the same direction but then turning around the axis substantially defined by the support points on the reference surface, the lower edge of the shuttering face of the reference surface is raised.

• figures 1 à 3 : un synoptique du procédé montrant la base de la banche dans trois positions différentes à savoir :
  • (figure 1) une position paroi coffrée,
  • (figure 2) une position paroi partiellement coffrée ou décoffrée selon le sens de la manoeuvre,
  • (figure 3) une position paroi décoffrée, banche pouvant être déplacée sur ses roulettes,
• figure 4 : un coffrage tunnel rétractile en position coffrée,
• figure 5 : un coffrage tunnel rétracile en position décoffrée,
• figure 6 : un coffrage tunnel demi-coquille avec la demi-coquille à droite sur la figure représentée en position coffrée et l'autre en position décoffrée.

It will be clearly understood with the aid of the description below given by way of nonlimiting example with regard to the attached drawing which schematically represents:

• Figures 1 to 3: a block diagram of the process showing the base of the panel in three different positions, namely:
  • (Figure 1) a formwork wall position,
  • (Figure 2) a partially shuttered or unsheathed wall position depending on the direction of the maneuver,
  • (Figure 3) a stripped wall position, panel can be moved on its wheels,
• FIG. 4: a retractable tunnel formwork in the formwork position,
• FIG. 5: a retractable tunnel formwork in the stripped position,
• Figure 6: a half-shell tunnel formwork with the half-shell on the right in the figure shown in the shuttered position and the other in the stripped position.

Referring to the drawing, it can be seen that, for the formwork-formwork of a vertical wall 1, such as a wall, of poured material, such as possibly reinforced concrete, above a reference surface 2, such as the upper face a floor slab or a screed are used two forms 3 each comprising a form face 4 formed by one 4 of the faces 4, 5 of a sheet 6 which, during the formwork, cooperates by its opposite face 5 with stiffeners 7, 8 arranged in two directions perpendicular to each other in order to guarantee the geometric correction of the formwork wall 1.

The form face 4 has a height substantially equal to the height of the wall.

These forms 3 are, for the shuttering of a wall, placed vertically with their shuttering faces 4 opposite and connected together by spacers (not shown) reserving between them a spacing equal to the thickness of the wall.

In order to guarantee the verticality of the forms 3, these are, by their stiffeners 7, 8, associated with a structure 9 offering at least one support point 10, 11, possibly adjustable, on the reference surface 2 to a certain distance behind the said form.

In the case where the vertical walls 1 are cast in isolation from horizontal walls 12 connecting the upper edges 13 of two successive walls, the structure (not shown) can be formed by triangular trusses provided at a suitable distance from a support on the surface reference.

• d'une part, à leur partie supérieure 14, par un platelage 15 en une ou plusieurs parties présentant une surface coffrante 16 formée par la face supérieure d'une tôle 17 dont la face inférieure 18 coopère avec des raidisseurs 19, 20 disposés selon deux directions perpendiculaires pour, lors du coffrage, garantir la correction géométrique de la paroi horizontale et,
• d'autre part, prés de leur base 21, par des traverses 22 réglables.

In the more general case where, on the contrary, simultaneously with the vertical walls 1, it is desired to pour the horizontal wall 12 extending between the upper edges 13 of said successive vertical walls 1, such as a ceiling tile 12, the forms 3 are, with their stiffened faces 5 opposite, arranged vertically with a distance between them corresponding to the distance between the vertical walls 1 of the same cell and connected together:

• on the one hand, at their upper part 14, by a deck 15 in one or more parts having a formwork surface 16 formed by the upper face of a sheet 17 whose lower face 18 cooperates with stiffeners 19, 20 arranged in two perpendicular directions to guarantee, during the formwork, the geometric correction of the horizontal wall and,
• on the other hand, near their base 21, by adjustable crosspieces 22.

In this case, the formwork 3 thus associated each directly produces the structure 9 offering the other formwork the fulcrum guaranteeing its verticality.

The faces 4, 16 shuttering thus combined give the entire shuttering device an inverted U shape called tunnel.

The deck 15 or at least one of its parts can be associated with a structure (not shown) for bearing on the reference surface.

Generally, the shuttering face 16 of the decking is made inseparable from that 4 of at least one of the forms.

For example (FIG. 6), the decking 16 is split into at least two sections which join according to joint planes parallel to the formwork 3 and each section adjoining a formwork has its formwork face 16 thus associated with that 4 of the corresponding formwork and has its transverse stiffeners 20 articulated on the vertical stiffeners 7 of the formwork 3 to allow formwork by deformation of the dihedral angle formed by the formwork faces 4, 16 considered, for example, by acting on a forestay 23 associated with the free end of the decking fraction 15.

In an alternative embodiment (Figures 4 and 5), the deck 15 is, by itself, at least locally stiffened only in a direction parallel to the formwork 3 and, during the formwork (Figure 4), to present the flatness required, rests freely on crosspieces 20 associated with the stiffeners of the formwork.

• d'une part, entre eux, sous la partie médiane du platelage et,
• d'autre part, à l'une de leurs extrémités 25 sur les raidisseurs 7 de l'une des banches 3.

To allow formwork, these support beams of the decking each consist of at least two sections 20 articulated around an axis parallel 24 to the forms:

• on the one hand, between them, under the middle part of the decking and,
• on the other hand, at one of their ends 25 on the stiffeners 7 of one of the forms 3.

The profiles of these crosspieces 20, commonly known as scissors, can be maneuvered so as to form between them an angle turning its concavity towards the deck 15 thus depriving the latter of its transverse stiffeners so that it can under its own weight or by pull curve (Figure 5) and ensure the formwork of the horizontal wall 12 but also from the top of the vertical walls 1 by tilting a few degrees due to the reduction in spacing induced in the upper part by the operation of the scissors where the name of the retractable tunnel usually given to it.

On the reference surface 2 (FIG. 2), pins 26 are provided, provided with vertical faces 26b rising over a small height, each defining the position of the plane of a face 48 of the wall 1 to be erected and against which the bases 29 of the formwork faces 4 of the formwork can then be brought into abutment to determine the position of the base of their formwork face in the plane of said reference surface but also for formwork offer firmer support than on concrete freshly poured.

These pins 26 may in known manner be formed of concrete crosses of any thickness but whose width of the vertical branches 27 and horizontal 28 corresponds to the width of the vertical and horizontal walls to be shuttered.

Between the formwork 3 forming each vertical wall 1, crosses are then simply engaged by one of their vertical branches until its horizontal branches stop on the top of the formwork so that above the horizontal branches is above the ceiling tile 12 which will be poured, the upper vertical branch 27 of the cross forms the mark 26 necessary for the wall 1 which will then be shuttered at the upper level.

The rest of the cross 26 will be embedded in the cast walls.

In order to facilitate the handling of these forms 3 and the structures 9 which are associated with them, said forms 3 are equipped at their base with rollers 31, 32 each turning generally freely around an axis 33 of a yoke 34 associated with the formwork so that in the stripped position, formwork ready for movement, it is supported on the reference surface 2 while the lower edge 35 of the formwork face 4 is spaced from this surface 2.

The form is also provided with means 36 which, on formwork, on the contrary hold these rollers above the plane of the reference surface.

• pour le coffrage :
  • . depuis la position décoffrée (figure 3), par basculement vers la paroi 1 à coffrer d'au moins la base 29 de la face 4 coffrante de la banche 3, en tournant à cet effet autour d'un axe sensiblement défini par les points d'appui 10 des roulettes 31 sur la surface de référence, on amène le bord inférieur 35 de la face coffrante 4 en appui sur la surface 2 de référence (figure 2) puis,
  • . en poursuivant le basculement vers la paroi 1 à coffrer d'au moins la base 29 de la face coffrante de la banche 3 mais en tournant à cet effet autour d'un axe sensiblement défini par le bord 35 inférieur de la face coffrante de la banche 4, on soulève les roulettes 31 de la surface de référence (figure 1) et inversement,
• pour le décoffrage :
  • . depuis la position coffrée (figure 1) par basculement d'au moins la base 29 de la face coffrante 4 de la banche 3 dans le sens de son écartement de la paroi coffrée 1, en tournant autour de l'axe sensiblement défini par le bord inférieur 35 de la face coffrante 4, on amène les roulettes 31 en appui sur la surface de référence 2 (figure 2) et,
  • . en poursuivant le basculement dans le même sens mais en tournant alors autour de l'axe sensiblement défini par les points d'appui 10 sur la surface de référence 2, on soulève le bord inférieur 35 de la face coffrante 4 de la surface de référence 2.

For the formwork, instead of reassembling the panel 3 and its casters from the reference surface 2 by maneuvering for this purpose support jacks on the reference face and using means for closing the gap thus created under the lower edge of the shuttering face before or after depending on the nature of these closing means, according to an essential characteristic of the process which is the subject of the invention:

• for formwork:
  • . from the stripped position (Figure 3), by tilting towards the wall 1 to be shuttered at least the base 29 of the shuttering face 4 of the formwork 3, by turning for this purpose around an axis substantially defined by the points d support 10 of the rollers 31 on the reference surface, the lower edge 35 of the formwork face 4 is brought to bear on the reference surface 2 (FIG. 2) then,
  • . by continuing the tilting towards the wall 1 to be cased of at least the base 29 of the formwork face of the formwork 3 but by turning for this purpose around an axis substantially defined by the lower edge 35 of the formwork face of the formwork 4, the rollers 31 are lifted from the reference surface (FIG. 1) and vice versa,
• for formwork:
  • . from the formwork position (Figure 1) by tilting at least the base 29 of the formwork face 4 of the form 3 in the direction of its separation from the formwork wall 1, by turning around the axis substantially defined by the lower edge 35 of the shuttering face 4, the rollers 31 are brought to bear on the reference surface 2 (FIG. 2) and,
  • . by continuing the tilting in the same direction but then turning around the axis substantially defined by the support points 10 on the reference surface 2, the lower edge 35 of the shuttering face 4 of the reference surface 2 is raised .

In a first operating mode which can be applied more precisely but not exclusively when the horizontal walls are poured independently of the vertical walls, the above-mentioned swings take place while preserving the flatness of the shuttering face of the formwork.

In a preferred operating mode (FIGS. 4 to 6), the aforementioned swings operate in one direction and in the other respectively by bending and de-bending the formwork face to give it, in profile view, a concavity turned towards the wall. and on the contrary during the formwork, cancel this concavity and present the required flatness.

One of the essential advantages of the process is of course to avoid the use of wall primers or under-rises since there is no longer a gap to plug under the lower edges of the shuttering faces.

Another important advantage specific to the process according to which the tilting is effected by bending-bending is, by the reduction in height that this induces to the formwork, a faculty for handling the formwork in the cell.

In the case where the forms are used independently of any formwork decking, they can nevertheless advantageously be used as a prefabricated slab support or pre-slab allowing then the simultaneous pouring of the ceiling and the walls notwithstanding the absence of decking.

• des roulettes d'appui 31, lors du décoffrage, sur la surface de référence 2 qui sont associées à la face coffrante 4 à une distance et à une hauteur telles qu'en position coffrée, ces roulettes soient placées entièrement au dessus du niveau du bord inférieur de la face coffrante 4,
• des moyens 37 de commande des basculements d'au moins la base de la face coffrante de la banche.

The means for implementing this method include in combination:

• support rollers 31, during formwork removal, on the reference surface 2 which are associated with the shuttering face 4 at a distance and at a height such that in the shuttered position, these rollers are placed entirely above the level of the edge lower of the form face 4,
• means 37 for controlling the tilting of at least the base of the formwork face of the formwork.

In a preferred embodiment, the tilting control means 37 comprise control means alternately, during formwork removal, bending and, during formworking, of sheet metal 6 bending from the formwork face in a direction giving to the face formwork, side view, during formwork removal, a concavity facing the wall 1.

To this end, only the horizontal longitudinal stiffeners 8 of the sheet metal of the panel 3 having the formwork face 4 are secured to the rear face 5 of said sheet 6 having the formwork face 4 so as to constantly ensure its longitudinal rigidity, the stiffeners vertical 7 being meanwhile, at least in their median part, independent of the sheet 6 and its horizontal stiffeners 3 and consisting of crosspieces which, in the shuttered position, simply bear against the horizontal stiffeners 8, these crosspieces 7 being constituted by '' at least two profiles, on the one hand, articulated together in the manner of scissors around a horizontal axis 38 behind the shuttering sheet 6 substantially at mid-height thereof and, on the other hand, connected to the one of their ends 39 at least indirectly respectively at the upper 40 and lower 41 edges of the panel 3.

Preferably, although this is only shown in FIG. 6, in the various embodiments, beyond their common axis, the sections constituting the branches of the scissors extend on the side opposite their end associated with the formwork so that this extension cooperates in the stiffening of the sheet.

For the same purpose, the spacer (not shown) connecting the formwork shuttering the two faces of the same wall will then preferably take support on a flange secured to this extension of one of the branches of the scissors, which flange, in the shuttered position, will itself bear on the other branch of the scissors.

The form further comprises a means 37 for operating scissors such as a screw or hydraulic jack.

The weight of the sheet does not assist the sheet in its bending, advantageously, the sheet may locally include connecting means between the sheet or at least one of its horizontal stiffeners and the scissors.

In order to control the simultaneous bending of the forms of the same tunnel, the scissors of the opposite forms are connected by a cross member 37 adjustable in length such as a screw or hydraulic jack which, during casting, also ensures the resumption of the hydrostatic thrust of the concrete.

The support on the reference surface 2 of the lower edge 35 of the shuttering face 4 can advantageously be done by means of an inflatable seal in order to absorb the irregularities due to the roughness of the reference surface.

The fact that the formwork 3 is designed as claimed above does not of course preclude the simultaneous formwork, in at least one cell, of a third vertical wall, perpendicular to the previous two, by means of a bottom panel ( not shown) whose peripheral tightness during formwork is for example ensured by an inflatable tube and which, during formwork, can be placed in an inclined position along the diagonal of the cell and out of it for example on a carriage.

With the above-mentioned means, of course, all the accessories known to date are combined, such as closure panels and slab stops.

Claims (10)

1. A method of erecting and dismantling shuttering for walls of cast material erected above a reference surface, using shutters (3) each comprising a shuttering surface (4) formed by one (4) of the surfaces (4, 5) of a plate (6), the opposite surface (5) of which, when the shuttering is erected, co-operates with stiffeners (7, 8) arranged in two mutually perpendicular directions so as to ensure the geometric correction of the shuttered wall (1),
      the said reference surface (2) being provided with markers (26) having vertical surfaces (26b) rising to a low height, each defining the location of the plane of a surface (48) of the vertical wall (1) to be erected and against which the bases (29) of the shuttering surfaces (4) of the shutters can then be brought to rest in order to determine the position of the base of the shuttering surface in the plane of the said reference surface, but also to provide a firmer support than on the freshly cast concrete when the shuttering is dismantled,
      the said shutters being:

   - in order to ensure the verticality thereof, connected by their stiffeners (7, 8) to a structure (9) providing at least one optionally adjustable supporting point (10, 11) on the reference surface (2) at a certain distance behind the said shutter,

   - independent of any planking of shuttering for a horizontal wall connecting two vertical walls of a same cell and also connected to optionally retractile planking comprising one or more parts to form a single-shell or half-shell tunnel,

   - in order to facilitate the handling thereof, provided at their bases with rollers (31, 32) each turning substantially freely about a spindle (33) of a cover (34) connected to the shutter in such a manner that, in the unshuttered state, it rests against the reference surface (2) while the lower edge (35) of the shuttering surface (4) is at a distance from the said surface (2),

   - furthermore, provided with means (36) which, when the shuttering is erected, conversely hold the said rollers above the plane of the reference surface (2),

      this method being characterised in that:

   - to erect the shuttering:
      starting from the unshuttered state, the lower edge (35) of the shuttering surface (4) is brought to rest against the reference surface (2) by tilting at least the base (29) of the shuttering surface (4) of the shutter (3) towards the wall (1) to be shuttered, for this purpose pivoting about an axis substantially defined by the supporting points (10) of the rollers (31) on the reference surface, then,
      the rollers (31) are raised from the reference surface, continuing the tilting of at least the base (29) of the shuttering surface of the shutter (3) towards the wall (1) to be shuttered, but for this purpose pivoting about an axis substantially defined by the lower edge (35) of the shuttering surface (4) of the shutter, and conversely,

   - to dismantle the shuttering:
      starting from the shuttered state, the rollers (31) are brought to rest against the reference surface (2) by tilting at least the base (29) of the shuttering surface (4) of the shutter (3) away from the shuttered wall (1), pivoting about the axis substantially defined by the lower edge (35) of the shuttering surface (4), and,
      the lower edge (35) of the shuttering surface (4) is raised from the reference surface (2), continuing the tilting in the same direction, but pivoting about the axis substantially defined by the supporting points (10) of the rollers (31) on the reference surface (2).
2. A method according to claim 1, characterised in that the tilting actions are carried out while preserving the flatness of the shuttering surface of the shutter.
3. A method according to claim 1, characterised in that the tilting actions are carried out in one or other direction by either bending or unbending the shuttering surface to provide it, viewed in profile, with a concavity facing the wall when dismantling the shuttering and, conversely, to eliminate this concavity and provide the required flatness when erecting the shuttering.
4. Means for carrying out the method of shuttering walls above a reference surface according to any one of claims 1 to 3, comprising shutters (3) themselves each comprising a shuttering surface (4) formed by one (4) of the surfaces (4, 5) of a plate (6), the opposite surface (5) of which, when the shuttering is erected, co-operates with stiffeners (7, 8) arranged in two mutually perpendicular directions so as to ensure the geometric correction of the shuttered wall (1),
      the said reference surface (2) being provided with markers (26) having vertical surfaces (26b) rising to a low height, each defining the location of the plane of a surface (48) of the vertical wall (1) to be erected and against which the bases (29) of the shuttering surfaces (4) of the shutters can then be brought to rest in order to determine the position of the base of the shuttering surface in the plane of the said reference surface, but also to provide a firmer support than on the freshly cast concrete when the shuttering is dismantled,
      the said shutters being:

   - in order to ensure the verticality thereof, connected by their stiffeners (7, 8) to a structure (9) providing at least one optionally adjustable supporting point (10, 11) on the reference surface (2) at a certain distance behind the said shutter,

   - independent of any planking of shuttering for a horizontal wall connecting two vertical walls of a same cell and also connected to optionally retractile planking comprising one or more parts to form a single-shell or half-shell tunnel,

   - in order to facilitate the handling thereof, provided at their bases with rollers (31, 32) each turning substantially freely about a spindle (33) of a cover (34) connected to the shutter in such a manner that, in the unshuttered state, it rests against the reference surface (2) while the lower edge (35) of the shuttering surface (4) is at a distance from the said surface (2),

   - furthermore, provided with means (36) which, when the shuttering is erected, conversely hold the said rollers above the plane of the reference surface (2),

      these means being characterised in that they comprise:

   - supporting rollers (31), when the shuttering is dismantled, on the reference surface (2) and connected to the shuttering surface (4) at a distance and a height such that in the shuttered state, the said rollers are positioned entirely above the level of the lower edge (35) of the shuttering surface (4),

   - means (37) for controlling the tilting movements of at least the base of the shuttering surface of the shutter.
5. Means according to claim 4, characterised in that the tilting control means comprise means for controlling alternately the bending, when the shuttering is being dismantled, and the unbending, when the shuttering is being erected, of the plate (6) of the shuttering surface in a direction providing the shuttering surface, viewed in profile, with a concavity facing the wall (1) when the shuttering is dismantled.
6. Means according to claim 5, characterised in that only the horizontal longitudinal stiffeners (8) of the plate of the shutter (3) having the shuttering surface (4) are connected to the rear surface (5) of the said plate (6) so as to ensure its longitudinal rigidity constantly, the vertical stiffeners (7) being, at least in their central portion, independent of the plate (6) and its horizontal stiffeners (8) and comprising crosspieces which, in the shuttered state, simply rest against the horizontal stiffeners (8), the said crosspieces (7) being formed of at least two profiled parts, on the one hand mutually articulated in the manner of scissors about a horizontal axis (38) behind the shuttering plate (6) substantially at mid-height thereof, and on the other hand connected at one of their ends (39) at least indirectly to the upper (40) and lower (41) edges of the shutter (3).
7. Means according to claim 6, characterised in that the shutter locally comprises connecting means between the plate or at least one of its horizontal stiffeners and the scissors.
8. Means according to claim 6 or 7, characterised in that, in order to control the simultaneous bending of the shutters of a same tunnel, the scissors of the opposing shutters are connected by a longitudinally adjustable crosspiece (37) such as a screw jack or hydraulic jack which, during casting, also ensures the recovery of the hydrostatic thrust of the concrete.
9. Means according to any one of claims 5 to 8, characterised in that they comprise, for the simultaneous shuttering of a third vertical wall in at least one cell, perpendicular to the two preceding walls, a back panel, the peripheral tightness of which is ensured by an inflatable tube when the shuttering is erected.
10. Means according to any one of claims 5 to 9, characterised in that the lower edge (35) of the shuttering surface (4) is supported on the reference surface (2) by means of a seal so as to absorb the irregularities due to the roughness of the reference surface.

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