FR2613395A1 - IMPLEMENTATION METHOD AND FORMWORK FOR MOLDED WALL PANEL END END SEAL - Google Patents

Abstract

THE INVENTION RELATES TO A PROCESS FOR MAKING AN END JOINT OF A MOLDED WALL PANEL IN THE SOIL, IN WHICH A TRENCH 1 IS DIGGED, A FORMWORK 2A IS PROVIDED AT ITS END, THE TRENCH IS CONCRETEED, AND IT IS EXTRACTS THE FORMWORK. PRIOR TO THE CONCRETING OF THE TRENCH, THE FACE OF THE FORMWORK ON THE CONCRETE SIDE IS COATED WITH A THIN MATERIAL 9A LIKELY TO BE ABANDONED IN THE TRENCH, AND THE FORMWORK IS SENSITIVELY EXTRACTED VERTICALLY.

Description

26 1 3395

  The subject of the present invention is a production method and a formwork for a wall panel end seal molded in the ground, and more particularly such a method in which a trench is hollowed out, a formwork is placed at its end, Concrete the trench and extract the formwork. In these processes, the trench is usually dug under bentonite sludge. Once the trench is dug, a formwork is immersed in the mud and placed at the end of the trench. Concrete is then

  cast to replace the mud, the concrete thus coming into contact with the formwork.

  When the concrete has set, a new trench is dug adjacent to the first one on the other side of the formwork, generally using this one

to guide the piercing machine.

  The problem that arises then is that of the extraction of the formwork. Indeed, the formwork adheres strongly to the concrete so that it is necessary to take off before extraction. This detachment is generally effected by a lateral displacement by means of jacks or wedges. These devices however have the disadvantage of being complex

and immobilize the site.

  The present invention aims to overcome these disadvantages.

  For this purpose, the first object of the invention is a method for producing a wall panel end seal molded in the ground in which a trench is hollowed out, a formwork is placed at its end, concretes the trench, and the formwork is extracted, characterized in that prior to concreting the trench, the face of the formwork side concrete is coated with a thin material may be abandoned in the

  trench, and that the formwork is extracted substantially vertically.

  The problem of adhesion of the formwork to concrete is therefore solved by the fact that is interposed between the formwork itself and the concrete, a material to be abandoned in the trench. The connection between this coating and the formwork being provided is very low, or such that it can be completely removed once the formwork set up, the extraction force of this formwork is thus

  practically limited to its weight alone.

  In a first embodiment, a sheet material capable of being folded is used as a thin material, and this sheet is held on the formwork by folding its edges over the

formwork edges.

- 2 - 2 6613395

  According to another embodiment, a sheet of magnetic material is used as a thin material, and this sheet is maintained.

  on the formwork using electromagnets.

  According to yet another embodiment, a sheet of relatively air-tight material is used as the thin material, and

  keeps this sheet on the formwork using suction cups.

  According to yet another embodiment, a sheet material is used as a thin material, and this sheet is fixed on the formwork using means of low mechanical resistance, such as welding spots or dowels, likely to break when

extraction of the formwork.

  The invention also relates to an end formwork for the implementation of the method as described above, characterized in that it comprises, on its concrete side, a thin coating

  likely to be abandoned in the trench.

  In a particular embodiment of the invention, this formwork comprises, for the maintenance of said coating, electromagnets or

suction cups.

  In another embodiment, the coating is fixed on

  the formwork using means of low mechanical resistance.

  It is also possible to provide a formwork comprising a groove in which is engaged an inflatable seal, the coating then being held on the formwork at least partially by

  its jamming in said groove with the aid of said inflatable seal.

  Non-limiting examples of particular embodiments of the invention will now be described with reference to the appended diagrammatic drawings in which: FIGS. 1 to 3 show three embodiments of the invention. In general, the method according to the invention comprises the known steps of digging in the ground a trench 1, usually under bentonite sludge, to dispose at the end of this trench a formwork 2a, 2b, 2c, for example equipped with a seal 3 of the type called "water-stop", to concretize the trench 1, to dig on the other side of the trench 1 with respect to the formwork a second trench 1 ', and to extract

the formwork.

  In the known methods, the extraction of the formwork had to be carried out, either before the concrete of the trench 1 had completely set in order to avoid too much adhesion, but this required a delay

- 3 - 26 1 3395

  very short between the concreting of the trench 1 and the extraction of the formwork, or to have means allowing a lateral displacement of the formwork to

  the trench 1 'to ensure its separation of the concrete from the trench 1.

  In the embodiments shown in the drawings, the forms 2a, 2b and 2c comprise a sole 4 on which are fixed two sealed boxes 5 delimiting between them a longitudinal groove 6. The seals 3 comprise an inflatable core 7 supporting two wings side 8 (Figure 1). One of the lateral wings 8 is engaged in the groove 6, as well as at least partially the core 7. The seal 3 is

  maintained between the two caissons 5 by inflating the core 7.

  According to the invention, the face of the formwork facing the concrete side of the trench 1 is coated with thin sheets 9a, 9b, 9c, may be abandoned in the trench during the extraction of the formwork. In the embodiment of Figure 1, the sheets 9a are made of magnetic material, for example galvanized steel, and are held on the formwork during the establishment of the latter by

electromagnets 10.

  In the case of Figure 2, the sheets 9b are made of a relatively airtight material such as metal or a synthetic material, and are held on the formwork 2b by suction cups 11. The suction cups 11l are arranged in holes formed in the walls of the boxes 5, and comprise a support grid 12 avoiding the puncture of the sheets 9b, and an O-ring seal 13 at the periphery of this grid. Means, not shown, make it possible to evacuate the caissons 5 so as to press the sheets 9b against the

outer walls of the formwork.

  In the case of Figure 3, the sheets 9c are made of a material capable of being folded, and are fixed on the formwork 2c by folding their edges 14 around the lateral edge of the sole 4, and their edges 15 inside the groove 6 where they are blocked from

  inflates the core of the seal 3.

  It is therefore sufficient, when it is desired to extract the formwork from the trench, to interrupt the supply of the electromagnets 10 in the case of Figure 1, to interrupt the suction of air in the boxes 5 in the case of Figure 2, and deflate the inflatable seal in the case of Figure 3. The coating 9a, 9b and 9c is then detached from the formwork itself, which can be extracted

4 2-6 32613395

  vertically because it has no adhesion to concrete

from the trench 1.

  Various variations and modifications can of course be

  made to the above description without departing from the scope and

of the spirit of the invention.

-5- 2613395

Claims (10)

  1. A method of producing a wall panel end seal molded into the ground, in which a trench (1) is hollowed out, a formwork (2a, 2b, 2c) is placed at its end, the trench is concreted. , and the formwork is extracted, characterized in that, before concreting the trench, the face of the concrete-side formwork is coated with a thin material (9a; 9b; 9c) that can be left in the trench,   and that the form is extracted substantially vertically.   2. Method according to claim 1, characterized in that a foldable sheet material (9c) is used as a thin material, and this sheet is held on the formwork by   folding of its edges on the edges of the formwork.   3. Method according to claim 1, characterized in that one uses, as thin material, a sheet of magnetic material (9a), and that one maintains this sheet on the formwork to using electromagnets (10).   4. Method according to claim 1, characterized in that a sheet (9b) of relatively airtight material is used as a thin material, and that this sheet is kept on the   shuttering with suction cups (11).   5. Method according to claim 1, characterized in that one uses, as thin material, a sheet material, and that one fixes this sheet on the formwork using means of weak mechanical resistance, such as weld points or dowels likely to   break during the extraction of the formwork.   6. End formwork for the implementation of the process   according to any one of claims 1 to 5, characterized in that   it has on its concrete side a thin coating (9a; 9b; 9c)   likely to be abandoned in the trench.   Formwork according to claim 6, characterized by the fact   it comprises electromagnets (10) for maintaining said coating.   - 8. Formwork according to claim 6, characterized by the fact   it includes suckers (11) for maintaining said coating.   9. Formwork according to claim 6, characterized in that said coating is fixed on the formwork using weak means. mechanical resistance.   10. Formwork according to claim 6, characterized in that it comprises a groove (6) in which is engaged an inflatable seal (3), said coating being held on the formwork - 6 - 2613395   at least partially by jamming in said groove with the aid of said inflatable seal.