FR2473402A1

FR2473402A1 - Pyrotechnical process for splitting concrete slab - uses chain of explosive charges with inverted V=section at definite centres along cut line

Info

Publication number: FR2473402A1
Application number: FR8000856A
Authority: FR
Original assignee: ALSETEX ARMEMENT ETUD
Current assignee: ALSETEX ARMEMENT ETUD
Priority date: 1980-01-15
Filing date: 1980-01-15
Publication date: 1981-07-17
Also published as: FR2473402B1

Abstract

The pyrotechnical process uses a chain of dihedral shape explosive charges (10) to split a concrete slab (1), being applied to the demolition of concrete pavements etc. Charges (10) have an inverted 'V' shape in cross ection and are placed at intervals along the cut line, the explosion of a single charge being used as a firing mechanism. Detonating wire (12) or an electric signal may be used to effect the explosion of the first charge. Intermittent charges connected by wire may be used on plain concrete slabs, and abutting charges without wire may be used on reinforced slabs. The charges may be cased (11) and stooled (13) a definite distance above the slab.

Description

La présente invention concerne un procédé pour effectuer la coupe rapide dtune dalle de béton par un moyen pyrotechnique et concerne également un dispositif pyrotechnique pour la mise en oeuvre de ce procédé, Une application particulière de l'invention est celle de la rdfection de routes ou de pistes d'atterrissage d'avions venant dt8tre bombardées. The present invention relates to a method for carrying out the rapid cutting of a concrete slab by a pyrotechnic means and also relates to a pyrotechnic device for the implementation of this method. A particular application of the invention is that of repairing roads or airstrips of planes coming from being bombed.

Pour couper des dalles en béton, on utilise actuellement des procédés mécaniques, lourds, fatigants, et dont la durée de mise en oeuvre est d'autant plus grande que la coupure à effectuer est longue. To cut concrete slabs, mechanical, heavy, tiring processes are currently used, the duration of implementation of which is greater the longer the cut to be made.

La pressente invention a pour but de remédier à ces inoonvénients et propose à cet effet un procédé permettant de couper des dalles de béton en un temps très court. Le procédé selon l'invention consiste
- à utiliser des charges creuses diédriques que l'on dispose en série sur la dalle, le long de la ligne à couper
- et à mettre à feu l'ensemble en faisant exploser l'une des charges.The purpose of the present invention is to remedy these drawbacks and to this end provides a method for cutting concrete slabs in a very short time. The method according to the invention consists
- to use dihedral hollow charges which are placed in series on the slab, along the line to be cut
- and ignite the assembly by detonating one of the charges.

La détonation se transmet de proche en proche à toutes les charges explosives en un temps très court et 1Bon obtient une coupure étroite et franche qui ne nécessite pas apres déblaiement, de remise en état de la partie découpée de la dalle. The detonation is transmitted step by step to all the explosive charges in a very short time and 1Bon obtains a narrow and frank cut which does not require, after clearing, to repair the cut part of the slab.

Les charges explosives sont avantageusement consti- tuées par des charges creuses diédriques allongées, admettant un plan de symétrie vertical. The explosive charges are advantageously constituted by elongated dihedral hollow charges, admitting a vertical plane of symmetry.

Dans le cas où la dalle ne comporte pas d'armature métallique, les charges explosives sont espacées les unes des autres et reliées chacune à la suivante par un cordeau détonant. Si au contraire, la dalle comporte une armature métallique, chaque charge sera disposée en contact avec la suivante. In the case where the slab does not have a metal frame, the explosive charges are spaced from each other and each connected to the next by a detonating cord. If, on the contrary, the slab has a metal frame, each load will be placed in contact with the next.

L'invention sera décrite à présent en détail en regard des dessins anexés dans lesquels
La figure 1 est une vue en coupe de la dalle de béton montrant la disposition des charges explosives diédraques au-dessus de cette dalle
La figure 2 est une vue en plan de la figure 1
La figure 3 est une me en plan de la dalle de béton après I'exposion des charges, et
La figure 4 montre une coupe transversale d'une charge explosive selon la ligne IV-IV de la figure 2.The invention will now be described in detail with reference to the appended drawings in which
Figure 1 is a sectional view of the concrete slab showing the arrangement of the dihedral explosive charges above this slab
Figure 2 is a plan view of Figure 1
FIG. 3 is a plan view of the concrete slab after the exposure of the loads, and
Figure 4 shows a cross section of an explosive charge along line IV-IV of Figure 2.

Avec référence aux figures 1 et 2 une dalle de béton 1 dépourvue d'armature métallique repose sur le sol 2. Des charges explosives 3 sont disposées en file sur la dalle, le long de la ligne selon-laquelle la coupure doit etre effectuée. With reference to FIGS. 1 and 2, a concrete slab 1 devoid of metallic reinforcement rests on the ground 2. Explosive charges 3 are placed in a line on the slab, along the line along which the cut is to be made.

Les charges 3 ne sont pas en contact tout à bout et chacune d'elles est reliée à la suivante par un cordeau détonant 4. The charges 3 are not in full contact and each of them is connected to the next by a detonating cord 4.

Le dispositif est mis à feu en faisant exploser lSun.e des charges 3 au moyen d'un cordeau détonant 5 ou d'un signal électrique. La détonation se transmet successive- ment à toutes les charges du dispositif par l'intermédiaire des cordeaux détonants 4
L'effet produit sur la dalle 2 est représenté à la figure 3 : des excavations profondes 6 ont été creusées dans la dalle de béton aux endroits où étaient placées les charges explosives 3. Ces excavations sont reliées entre elles par des fissures 7, de sorte que la dalle se trouve coupée en deux morceaux 8 et 9.The device is ignited by detonating lSun.e of the charges 3 by means of a detonating cord 5 or an electrical signal. The detonation is transmitted successively to all the charges of the device via the detonating cords 4
The effect produced on the slab 2 is shown in Figure 3: deep excavations 6 were dug in the concrete slab at the places where the explosive charges were placed 3. These excavations are interconnected by cracks 7, so that the slab is cut into two pieces 8 and 9.

Le fait de laisser un intervalle entre deux charges voisines permet de réduire le nombre de charges utilisées. Leaving an interval between two neighboring charges reduces the number of charges used.

Ceci est possible dans le cas ou la dalle ne comporte pas d'arcature métallique. Si la dalle comporte une armature metallique, le procédé de coupure par charges creuses explosives diédriques peut encore être utilisé en alignant lesdites charges bout à bout, sans espacement entre deux charges voisines. Dans ces conditions, la détonation se transmet par 11 influence d'une charge à la charge voisine et provoque à la fois la coupure de la dalle de béton et de l'armature métallique.This is possible in the case where the slab does not have a metal arch. If the slab has a metallic reinforcement, the method of cutting by dihedral explosive hollow charges can still be used by aligning said charges end to end, without spacing between two neighboring charges. Under these conditions, the detonation is transmitted by the influence of a charge to the neighboring charge and causes both the cutting of the concrete slab and the metal reinforcement.

Avec référence à la figure 4, la charge. creuse explosive comporte un explosif 10 contenu à l'intérieur d'un revêtement métallique 11 de forme diédrique admettant un plan de symétrie vertical. With reference to Figure 4, the load. explosive hollow comprises an explosive 10 contained inside a metallic coating 11 of dihedral shape admitting a vertical plane of symmetry.

Le point d'amorçage 12 est situé au voisinage du sommet de la charge. Des supports 13 maintiennent la charge à bonne distance d'action au-dessus de la dalle 1. The starting point 12 is located in the vicinity of the top of the load. Supports 13 keep the load at a good operating distance above the slab 1.

La fore du revetesent est prévue pour que la hauteur de charge soit relativement plus grande que ia largeur de charge, afin d'augmenter l'effet produit par la détonation dans le plan de symétrie du dièdre sans augmenter inutilement les effets latéraux. The front of the coating is designed so that the loading height is relatively greater than the loading width, in order to increase the effect produced by the detonation in the plane of symmetry of the dihedron without unnecessarily increasing the lateral effects.

Claims

CLAIMS,

1.- Method of rapidly cutting a concrete slab, characterized in that it consists

- to use dihedral hollow charges 3 which are arranged in series on the slab 1, the ong of the line to be cut;

- and to ignite the assembly by detonating one of the charges.

2.- Method according to claim 1; characterized in that jion detonates one of the charges by means of a detonating cord 5.

3.- Method according to claim 1, characterized in that one of the charges is detonated by means of an electrical signal.

4. Pyrotechnic device for implementing the method according to one of the preceding claims, characterized in that it comprises a plurality of charges.

elongated dihedral hollow 3, arranged horizontally one after the other on the slab 1, along the line along which the cut must be made.

5. A pyrotechnic device according to claim 4, characterized in that each of the charges is spaced from the next and connected to the latter by a detonating cord 4.

6. A pyrotechnic device according to claim 4, particularly suitable for cutting a concrete slab comprising a metal frame, characterized in that the successive charges 3 are placed end to end, the detonation being transmitted by the influence of a charge to neighboring charge.

7.- Pyrotechnic device according to one of the reven dcations 4 to 6, characterized in that each of the charges 3 comprises an explosive 10 contained inside a metallic covering 11 of dihedral shape admitting a plane of symmetry vertical, the height of the explosive being relatively large with respect to its width so as to increase the effect produced by the detonation in the plane of symmetry of the charge.

8.- Pyrotechnic device according to one of claims 4 to 7, characterized in that the charge is provided with supports 13 intended to keep it at a good distance from the action of the slab.