JPS60215919A - Apparatus for separating tensile material of compression anchor prestressed by formation of destruction objective position - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a method for positioning the tensile member of a pretensioned compression anchor at a predetermined location of its length, in particular at the point of transition from the anchored length to the free copper length, at the fracture target location. The present invention relates to a device for separating by forming a tensile shear, consisting of a ring sleeve that surrounds in the region of the target fracture location to be formed. The ring sleeve is filled with a thermite reaction mixture and has an igniter embedded therein which is electrically released.

Compression anchors are tensile, like! ! It is constructed from l material. That is, it is introduced into a borehole and is connected to the borehole wall and the surrounding ground by press-fitting a hardened material such as cement mortar at the deepest point of the borehole. The compressed body thus produced is a structural part to be anchored through the remaining part of the tensile material, which may consist of one or several elements consisting of steel rods, steel wires, steel wires. They engage in a fist bump.

The length of the tensile material embedded in the compressed body is the fixation length Lv,
The remaining part that is free to stretch for the purpose of pre-tensioning is the free copper length L.
It is called fat.

Compression anchors serve to permanently anchor buildings into the ground, but they can also be used temporarily, for example for the rear anchorage of foundation hole walls. If a temporarily used compression anchor penetrates into the adjacent ground, the anchor typically must be removed upon completion of the construction work for which it was used.

In order to remove the compression anchor, it is usually installed at a place where it can be separated for the tensile beam on the way from the anchorage length Lv to the free copper length Lfst, and the free part of the tensile beam is pulled out from the drilled hole, and if necessary, can be made available again. The compacts themselves, which are sometimes longer than about 4 to 8 meters, can often be easily removed by cutting the flat surface, for example with a bulldozer, during excavation work on adjacent land.

Of the various methods for breaking the tension members of compression anchors, the use of heat is the most important for reducing the tensile strength of steel. On the one hand, the tensile strength of arbitrarily formed tensile shears can be reduced by the use of heat, and on the other hand, the means necessary for the generation of heat can be integrated with the tensile shears without significantly enlarging the diameter of the borehole. and generally can continue to operate for heat generation for a long time. After all, if the fracture target location is provided by a reduction in strength due to the action of heat, the tension member can utilize its entire cross section during all conditions of use.

In order to generate the heat necessary to reduce the tensile strength of the tensile material, the fracture target location of the tensile material is easily separated by an exothermic reaction, for example using a thermite reaction mixture, and the tensile material is easily separated. It is known to heat tensile steel to a temperature that reduces its tensile strength so that it can be pulled out of a drilled hole (German Patent No. 24 33 244).

The thermite mixture is then placed inside the ring sleeve. This annular sleeve surrounds the tension member at a distance in the area of the target fracture location to be formed. There is an ignition device in the ring sleeve.

Since compression anchors are often submerged in ground water, it is not necessary to protect the ignition system from extinguishing the fire due to moisture intrusion, and during combustion, the necessary heat can create a destructive target position. Before the ring sleeve ruptures, it is also necessary to prevent water from coming into contact with the burning thermite mixture i and cooling or dissipating this mixture. A further problem is that this mixture significantly reduces its volume during combustion and, in any case, contracts at the lower end of each of the ring sleeves if the anchor is inclined. This causes the following dangers. That is, a part of the mixture in a scorching fluid state flows out from the annular space between the tensile member and the ring sleeve into the ground below.
This means that the amount of mixture remaining inside the sleeve is so small that it is not possible to dissolve the tensile material in such a way that it can be reliably separated at the target fracture location.

Problems to be Solved by the Invention The basic problem of the invention is to improve the device described at the beginning to reliably break off the anchor tension member at the predetermined breakage target location, especially when the compression anchor is located in underground water. There is a particular thing.

Means for Solving the Problem This problem is solved by the configuration of the present invention having the following features. That is, the ring sleeve is constituted by an outer tube having at least one inner tube that accommodates the tension member or a single element of the tension member, and the end surface of the hollow space formed between the outer tube and the inner tube is The outer tube is sealed with lids inserted from both ends, and a plug made of a fire-resistant hardened material, such as concrete, is placed in the hollow space thus formed with open ends. It is.

The igniter is made of a material enclosed in a vertically elongated cartridge that ignites as rapidly as possible and burns quickly at a high temperature.The ignition device is made of a material that ignites as rapidly as possible and burns quickly at high temperatures. The agent is in direct contact with the ignition tube, which is supplied with electrical current. Enclosed in the cartridge, the material of the igniter is conveniently a mixture of copper and thermite powder.

Advantageously, the outer tube is connected at its air end to an extension tube, which is connected in a sealed manner to a sheath which surrounds the tension member in the area of the free copper length. Advantageously, the outer tube and/or the inner tube are made of metal. Similarly, the extension tube is advantageously made of metal and welded to the outer tube.

The space surrounding the tensile member in the area of free copper length is preferably made of plastic.

The ignition tube is advantageously arranged in the area of 7-s free copper length, and the extension tube reaches the air end of the outer tube in the bung. The ignition tube can be embedded directly into the material of the plug with a portion of its extension.

effect The advantages of this invention are first recognized in the following points.

In other words, it is provided in addition to the lid on the end surface side of the ring sleeve.
Complete dissolution of the lid is prevented by a plug of refractory hardening material, such as concrete, which may penetrate into the narrow annular space between a portion of the lid material and the inner tube surrounding the tensile material. Even when the tap is closed, the material cools rapidly and fills this annular space.

Due to this particular construction of the igniter, and in particular the selection of materials that ignite as quickly as possible and burn rapidly at high temperatures, such as copper-thermite mixtures, the thermite mixture enclosed in the ring sleeve ignites rapidly and And it burns quickly. The copper-thermite mixture in the igniter ignites rapidly at about 1900°C and then burns. This is because, for example, the ignition temperature of thermite is approximately 1000° C., thus ensuring a rapid combustion of thermite and preventing ground water from entering the powder train after combustion of the inner tube. The ignition device consisting of a copper-thermite mixture is conveniently placed in a long cartridge, which extends over as long as possible the length of the ring sleeve, which also achieves rapid ignition of the thermite mixture. be done.

Example The figure showing one embodiment will be described in more detail.

FIG. 1 shows a longitudinal section of a saw tension member 1, for example a compression anchor with a steel weave, inserted into a drilled hole 2. FIG. A compressed body 3 is formed in the lower part of the drilled hole 2 by press-fitting a hardening material such as cement mortar. A tension member 1 is fixed within the anchor over a fixed length Lv. The tension member 1 is freely extensible over the remaining part of its total length, that is, the free steel length L fat,
For example, in order to secure the foundation hole wall 4, it is fixed on the air side with an anchor member 5. Anchor members are not subject to this invention.

Over the area of the free copper length L fst the tension member 1 is protected from corrosion by a sheath, for example a plastic tube. Drills can also be plugged in this area.

A device 6 is embedded in the compressed body 3 in a region ranging from the fixed length Lv to the free steel length Lfst. This device makes it possible to set the target fracture position by exerting a thermal effect on the tension member 1.

At this target fracture position, the tension member 1 can be separated by applying tension from the outside or by maintaining the anchoring force, so the part of the tension member extending into the area of the free steel length L fat is drilled. It can be drawn from 2. An example of such a device for forming a destruction target location is shown in the second example.
The figures are shown in longitudinal section and cross section in FIG. 4.

In the illustrated example, the device 6 is constructed as a ring sleeve consisting of an outer tube 7 made of steel. The outer tube 7 has its end faces closed with two lids 8 and 9.

These lids 8 and 9 are each spaced apart a from the end of the outer tube 7.
and b apart. The tension member 1 has a multi-part construction in the illustrated example. That is, it is composed of three single elements 1'. Therefore, three inner tubes 10 are arranged inside the outer tube 7, these inner tubes are passed through appropriate holes in the lids 8 and 9, and a single element 1' is placed in each of the holes. Each of them is passing through. The inner tube 10 is somewhat longer than the outer tube 7 and protrudes to both sides.

A 7-strip 1 made of plastic, for example polyethylene, surrounding the tension member 1 in the area of free steel length L fst
1, an extension tube 12 is inserted into the air side end of the outer tube 7 and is connected to the outer tube 7 by a reed and an explosion bead 13. In the part projecting from the outer tube 7, the extension tube 12 has a panfluvia 1, e.g. a ring-shaped explosion weld bead, so that in this region it is possible to install the tube in a sealed manner by means of externally mounted supports or clamping bands. .

A hollow tube 15 formed between the inner wall of the outer tube 7 and the outer wall of the inner tube 10 is filled with a thermite mixture, for example thermite powder. This mixture requires 1 long cartridge.
6, this cartridge contains a copper-thermite mixture. Incorporated into this copper-thermite mixture is an ignition agent 17, such as is used, for example, in explosive loading. This igniter 17 has an ignition pipe 1
The ignition tube is passed to the outside through a suitable hole in the lid 9 and is placed in a plastic sheath for mechanical protection.

A concrete plug 20 is placed in the space created by pulling the lids 8 and 9 inward from the front end of the outer tube 7.
And 21 is packed. Plug 21 inside extension tube 12
at the air end of the device 6 still protrudes from the front end of the outer tube 7.

A sheath 19 for protecting the ignition tube 18 is also embedded in the plug 21. A small portion of the sheath 19 is directly embedded in the concrete of the plug 21 in order to achieve as complete a seal as possible against liquid entering from the outside.

The ring sleeve 6 can be introduced into the borehole 2 at the same time as the tension member 1. The ring sleeve occupies only slightly more space in its radial extension than the tension member itself;
From the beginning, all the steps necessary for the subsequent reaction and formation of the destruction target location are taken. By applying voltage to the ignition tube 18, the igniter 17 is ignited and the copper-thermite mixture in the cartridge 16 is caused to react. This mixture ignites rapidly and burns at very high temperatures. As a result, the thermite powder filling the remaining portion of the hollow space 15 is also rapidly reacted, and the thermite powder becomes stranded in a short time.
' is melted, and the action of heat causes a decrease in strength that ensures the formation of the target fracture position.

Due to the angle of inclination of the anchor, a scorching fluid mixture flows into the stopper 2.
Outflow is prevented by 0 or 21. The spigot also constitutes a positive seal against intruding ground water during the time until the igniter is used.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view of the compression anchor, Fig. 2 is an enlarged longitudinal cross-sectional view of the ring sleeve filled with a thermite mixture, Fig. 3 is a cross-sectional view taken along line n+-m in Fig. 2, 4
The figure is a cross-sectional view taken along the line ■-■ in FIG. 2. In the figure, reference numeral 1...tensile material, 1'...1 single element, 6...
・Ring sleeve, 7... Outer tube, 8.9... Lid, 1
0--inner tube, 15... middle space, 20.21... stopper, a, b... interval.

Claims (1)

[Claims] 1) Pre-tensioned tension member of a compression anchor by forming a fracture target position at a predetermined position of the length of the tension member, mainly at the transition point from anchored length to free copper length. An electrically releasable ignition device is embedded in the reaction mixture, consisting of a ring sleeve filled with a thermite reaction mixture, which surrounds in the area of the destruction target location to form a tensile member for separation. , in the device, the ring sleeve (6)
is the tensile material (1) or a single element of the tensile material (1) (
It consists of an outer tube (7) having at least one inner tube (10) accommodating an outer tube (7) and an inner tube (
The end side of the hollow space (15) formed between the outer tube (10) and the inner space (15) is closed by the lid (8, 9), and the lid is arranged at a distance (asb) from the end of the outer tube (7). A device characterized in that the hollow space thus formed, which is open at the end, is filled with plugs (20, 21) of a fire-resistant hardening material such as concrete. 2) The ignition device is enclosed in a long cartridge (16) and is made of a material that ignites as rapidly as possible and burns rapidly at high temperatures, and this material contains an igniter (17) consisting of a flammable material. 2. The device according to claim 1, wherein the ignition agent is buried and is in direct contact with the ignition tube (18), which is supplied with electrical current. '5) Device according to claim 2), characterized in that the material of the igniter, enclosed in the cartridge (16), is a mixture of copper and thermite powder. 4) The outer tube (7) is connected to an extension tube (12) at its air side end, and the extension tube is hermetically connected to a sheath (11) that surrounds the tensile material within the free copper length. The device according to any one of claims 1) to 3). 5) the outer tube and/or the inner tube (10) are made of metal;
The device according to any one of claims 1)-4). 6) The device according to claim 5, wherein the extension tube (12) is made of metal and is welded to the outer tube (7). 7) The sheath (11) surrounding the tensile member (1) in the area of the free copper length is made of plastic, claim 5).
or the device described in 6). 8) Ignition tube (18) is sheathed (19) in the area of free copper length
The sheath is placed inside the outer tube and the sheath is connected to the plug (
21) The device according to any one of claims 1) to 7). 9) Device according to claim 8, characterized in that the ignition tube (18) is partially embedded in the material of the plug (21).