EP0583725A1 - Device for separating the tension rod of a soil anchor at a provided location - Google Patents

Device for separating the tension rod of a soil anchor at a provided location Download PDF

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Publication number
EP0583725A1
EP0583725A1 EP19930112845 EP93112845A EP0583725A1 EP 0583725 A1 EP0583725 A1 EP 0583725A1 EP 19930112845 EP19930112845 EP 19930112845 EP 93112845 A EP93112845 A EP 93112845A EP 0583725 A1 EP0583725 A1 EP 0583725A1
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EP
European Patent Office
Prior art keywords
tension member
coil
heat
point
steel
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EP19930112845
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German (de)
French (fr)
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EP0583725B1 (en
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Walter Bau AG
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Dyckerhoff and Widmann AG
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Publication of EP0583725A1 publication Critical patent/EP0583725A1/en
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    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/74—Means for anchoring structural elements or bulkheads
    • E02D5/76—Anchorings for bulkheads or sections thereof in as much as specially adapted therefor
    • E02D5/765—Anchorings for bulkheads or sections thereof in as much as specially adapted therefor removable
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T83/00—Cutting
    • Y10T83/04—Processes
    • Y10T83/0405—With preparatory or simultaneous ancillary treatment of work
    • Y10T83/041—By heating or cooling
    • Y10T83/0414—At localized area [e.g., line of separation]

Definitions

  • the invention relates to a device for severing a tension member of a compression anchor consisting of ferromagnetic material at a predetermined location according to the preamble of patent claim 1.
  • a grouting anchor has a tension member which is inserted into a borehole and is brought deeply into the borehole by injecting hardening material, such as cement mortar or the like, with the borehole wall and thus with the surrounding soil.
  • hardening material such as cement mortar or the like
  • the tension member can be formed from a single element or from several elements, which in turn can consist of steel rods, wires, strands or even steel tubes.
  • the length of the tension member over which it is embedded in the compression body is referred to as the anchoring length L v , the remaining length, which is freely stretchable for the purpose of prestressing, as the free steel length L f .
  • Grout anchors can be used to permanently anchor structures in the ground; but they can also be used only temporarily, such as. B. for backward anchoring of the wall of an excavation pit. If a temporary grouting anchor extends into a neighboring property, it usually has to be removed after completion of the construction work for which it was used.
  • a separating option for the tension member is usually provided at the transition from the anchoring length L v to the free steel length L f , so that the free part of the tension member can be pulled out of the borehole and possibly recovered.
  • the grout itself which rarely has a length greater than about 4 to 8 m, can, when excavating work in the neighboring property, e.g. B. with bulldozers, mostly easy to remove.
  • the use of heat to reduce the strength of the steel tension member is of the greatest importance because the means necessary to generate heat are installed together with the tension member without a substantial increase in the borehole diameter and are also operable over a relatively long period of time can be held.
  • the tension member can be used with its full cross-section for the entire duration of its use.
  • the tension member In order to generate the heat necessary to reduce the tensile strength of the tension member, it is known to use the tension member in the area of the predetermined breaking point by means of the exothermic reaction, e.g. B. an aluminothermic mixture to heat (FR 22 74 740).
  • the exothermic reaction e.g. B. an aluminothermic mixture to heat (FR 22 74 740).
  • an ignition system In order to trigger the exothermic reaction, an ignition system is required which is difficult to keep ignitable when the armature is installed, which can extend over a long period of time.
  • the invention has for its object to provide a way to achieve such a high temperature level by using electrical energy in the steel tension member at the intended separation point in the shortest possible time that the separation occurs reliably and completely, so that the free steel length can be easily pulled out of the borehole.
  • the invention is based on the knowledge that by using induction in a frequency range which allows transmission of the electrical energy via a commercially available feed cable, only heating of the tension member up to the Curie temperature is possible because the ferromagnetic material of the tension member, i.e. the Steel, after which it becomes largely paramagnetic and therefore only permits a very limited supply of energy by induction.
  • the basic idea of the invention is that an additional possibility must be found for heating above the Curie temperature as far as possible up to the melting point.
  • this consists in the arrangement of a tubular core made of electrically conductive, heat-resistant and paramagnetic material, preferably austenitic steel, between the primary winding and the steel tension member to be separated.
  • the medium-frequency electrical current of 5 to 30 kHz which can be generated by means of suitable systems and can be transported over lengths of up to about 50 m without major losses to the intended separation point, in the tension member to be separated, which is how a short-circuited secondary winding acts, eddy currents generated, through which the entire cross-section of the tension member is heated evenly. It does not matter whether the clear cross section of the tubular core is completely or only partially filled by the material of the tension member or whether the tension member is wholly or locally in heat-conducting connection to the tubular core. Depending on the circumstances, any gaps can be filled with a gaseous (e.g. air), liquid (e.g. water) or solid (e.g. cement mortar, plastic) medium. In any case, the penetration depth of the electrical current should be selected so that it extends approximately to the center of the clear cross section of the tubular core, regardless of where the tension member or the tension members are located within this cross section.
  • a gaseous e.g. air
  • liquid
  • the tubular core made of paramagnetic material which allows electrical energy to pass through to the tension member, also acts as a short-circuited secondary winding, which heats up due to its electrical conductivity. Because there is a very large temperature gradient in this phase, the heat can be given off radially inwards, i.e. against the tension member.
  • the high temperature resistant thermal insulation layer between the tubular core and the primary winding prevents heat from flowing radially outwards.
  • the second phase i.e. after the Curie temperature has been reached, electrical energy is still supplied to the same extent. Since the tension member has greatly reduced ferromagnetic properties in this phase, the proportion of induction is limited so that only little energy is consumed. The electrical energy still present in this phase is converted almost exclusively into heat in the tubular core due to the transformer effect. This heat is then transferred to the tension member by heat conduction and heat radiation, so that the melting point can be reached within the service life of the coil.
  • the temperature level required for severing the steel tension member depends on the one hand on the material properties of the tension member and, on the other hand, on the tension or elongation conditions in the tension member as a result of existing or applied tensile forces and on the size of the freely movable or freely stretchable partial lengths of the tension member. Any space filling between the individual elements of the tension member practically influences the rate of temperature rise depending on the proportion of the cross-sectional area below the Curie temperature not and only slightly above the Curie temperature, namely only if it is in solid form and a large proportion of the cross-sectional area.
  • the limit cases for the application of the invention are given by the existing mechanical tensile stress on the one hand by a slack steel tensile member, which has to be practically melted for severing, and on the other hand by a purely mechanically tensioned steel tensile member, which without heating in the area of the free steel length L. f failed somewhere.
  • Fig. 1 shows a longitudinal section through a compression anchor, which consists of a steel tension member 1, z. B. a bundle of steel wire strands, which is inserted into a borehole 2.
  • a grout 3 is generated in the compression body 3.
  • the tension member 1 over a part 1 'of its total length, the so-called Anchorage length L v , anchored.
  • the tension member 1 is freely stretchable over the remaining part 1 ′′ of its total length, the so-called free steel length L f .
  • the tension member 1, z. B. to secure a pit wall 4, anchored by an anchor 5; the anchor 5 is not the subject of the invention.
  • a device 6 by means of which a predetermined breaking point can be created by the action of heat on the tension member 1.
  • the tension member 1 can be severed at this predetermined breaking point, so that its part 1 ′′ extending over the area of the free steel length L f can be pulled out of the borehole 2.
  • the device 6 can either be in the free part 1 ′′ of the tension member 1, that is to say outside the compression body 3, but it can also — as shown — be embedded in the compression body 3.
  • this part can be moved longitudinally through the pressing body 3 and at the lower end thereof by means of suitable anchoring means, e.g. B. anchored under pressure, be anchored.
  • suitable anchoring means e.g. B. anchored under pressure
  • the device 6 is located at the lower end of the tension member 1.
  • FIG. 2 and 3 An embodiment of an inventive design of the device 6 for forming a predetermined breaking point is shown in Figs. 2 and 3 in longitudinal and cross section on a larger scale.
  • the device 6 has the shape of an annular sleeve which can be pushed onto the tension member 1 before it is installed in the borehole 2.
  • the device 6 consists of an inside-out structure a tubular core made of austenitic steel, the so-called carrier tube 7, and a high-temperature-resistant thermal insulation layer 8 arranged thereon.
  • a coil 9 which acts like the primary winding of a transformer.
  • the coil 9 preferably consists of an even number of layers, e.g. B. from two layers to be able to lead the two phases of a supply line 10 on the same side of the coil 9 for anchoring 5.
  • the turns of the coil 9 are insulated from high temperatures, e.g. B. first coated with a thermal varnish and then wound with glass fibers.
  • the tension member 1 consists of a bundle of seven individual steel wire strands 11, which are embedded directly in the compression body 3 in the area of the anchoring length L v and each individually in the area of the free steel length L f of protective tubes 12 made of plastic, for. B. PE, are encased. To secure the position or to protect against water, for example, the spaces between the individual strands 11 and the inner wall of the support tube 7 z. B. filled with polyurethane foam.
  • FIG. 4 Another embodiment of a device according to the invention is indicated in FIG. 4. While the design of the device 6 itself corresponds to that described in connection with FIG. 2, the individual strands 11 of the tension member 1 are arranged here in the area of the free steel length L f within a single protective tube 13. The hardening material pressed in to produce the compression body 3 is prevented by a seal 14 from penetrating into the interior of the protective tube 13.
  • the coil 9 is supplied with electrical current of a frequency via the supply line 10 of about 5 to 30 kHz and a voltage of about 500 to 800 V.
  • the electrical energy can be provided via a system for generating electrical energy of higher frequency and can be supplied via a feed cable.
  • eddy currents are hereby induced in this or in its individual elements, which lead to a relatively rapid heating up until the Curie temperature is reached.
  • the support tube 7 made of austenitic steel similar to the tension member 1 itself, acts as a short-circuited winding and also heats up.
  • the steel of the tension member 1 After the Curie temperature has been reached, the steel of the tension member 1 largely loses its ferromagnetic properties and behaves practically paramagnetically. Since electrical energy continues to be supplied, but only a little is consumed by the tension member 1, a greater electrical output than before is available for heating the carrier tube 7, which continues to act as a secondary coil. In this way, the heating of the tension member can be carried out practically up to the melting point.
  • the degree to which the reduction in strength must be carried out depends on the tension or elongation still existing in the tension member 1. If the tension member is still tensioned at the time of severing, a lower temperature is sufficient for cutting through than in the cases in which the tension member has only a low tension or even is without tension.
  • An advantage of the design of the device 6 according to the invention is that its functionality and that of the electrical feed cable can be checked at any time by conventional electrical measuring methods.
  • the device 6 can only be operated with the corresponding electrical system of higher frequency; unwanted or unauthorized operation of the device, such as. B. by external energy sources such as lightning can be excluded.

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  • Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Mining & Mineral Resources (AREA)
  • Paleontology (AREA)
  • Civil Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Piles And Underground Anchors (AREA)
  • General Induction Heating (AREA)
  • Wire Processing (AREA)
  • Earth Drilling (AREA)
  • Forging (AREA)
  • Perforating, Stamping-Out Or Severing By Means Other Than Cutting (AREA)

Abstract

Eine Vorrichtung (6) zum Durchtrennen eines aus ferromagnetischem Material bestehenden Zugglieds (1) eines Verpreßankers an einer vorgegebenen Stelle, wobei durch Verminderung seiner Zugfestigkeit in dem Zugglied (1) eine Sollbruchstelle erzeugt wird, umfaßt eine zusammen mit dem Zugglied (1) einbaubare, dieses an der vorgesehenen Trennstelle rohrförmig umschließende Spule (9), die zum Erzeugen einer Sollbruchstelle durch Verminderung der Zugfestigkeit des Zugglieds infolge Wärmeeinwirkung durch Induktion mit elektrischem Strom beaufschlagbar ist. Dabei ist die Spule (9) als Primärwicklung unter Zwischenschaltung einer hochtemperaturbeständigen Wärmedämmschicht (8) auf einem rohrförmigen Kern (7) aus elektrisch leitendem, hitzebeständigem und paramagnetischem Material angeordnet, wobei der Kern (7) eine erste Sekundärwicklung und das Zugglied (1) eine zweite Sekundärwicklung bilden. Zum Durchtrennen des Zugglieds wird die Spule (9) mit elektrischer Energie einer Frequenz von etwa 5 bis 30 kHz und einer Spannung von etwa 500 bis 800 V beaufschlagt. Erfindungsgemäß erwärmt sich das Stahlzugglied (1) bis zur Curie-Temperatur vor allem aufgrund der Eindringtiefe des darin induzierten elektrischen Stromes und oberhalb der Curie-Temperatur vor allem durch Wärmeleitung und -strahlung des rohrförmigen Kerns. <IMAGE>A device (6) for severing a tension member (1) made of ferromagnetic material of a compression anchor at a predetermined point, a predetermined breaking point being generated in the tension member (1) by reducing its tensile strength, comprises a position that can be installed together with the tension member (1). this at the provided separation point surrounding tubular coil (9) which can be acted upon by induction to produce a predetermined breaking point by reducing the tensile strength of the tension member due to the action of heat. The coil (9) is arranged as a primary winding with the interposition of a high-temperature-resistant thermal insulation layer (8) on a tubular core (7) made of electrically conductive, heat-resistant and paramagnetic material, the core (7) being a first secondary winding and the tension member (1) one form second secondary winding. To cut the tension member, the coil (9) is subjected to electrical energy at a frequency of approximately 5 to 30 kHz and a voltage of approximately 500 to 800 V. According to the invention, the steel tensile member (1) heats up to the Curie temperature primarily due to the penetration depth of the electrical current induced therein and above the Curie temperature primarily due to thermal conduction and radiation of the tubular core. <IMAGE>

Description

Die Erfindung betrifft eine Vorrichtung zum Durchtrennen eines aus ferromagnetischem Material bestehenden Zugglieds eines Verpreßankers an einer vorgegebenen Stelle gemäß dem Oberbegriff des Patentanspruchs 1.The invention relates to a device for severing a tension member of a compression anchor consisting of ferromagnetic material at a predetermined location according to the preamble of patent claim 1.

Ein Verpreßanker weist ein Zugglied auf, das in ein Bohrloch eingeführt und im Bohrlochtiefsten durch Einpressen von erhärtendem Material, wie Zementmörtel oder dergleichen, mit der Bohrlochwandung und so mit dem umgebenden Erdreich in Verbund gebracht wird. Dadurch entsteht ein Verpreßkörper, der über den restlichen, zur Bohrlochmündung führenden Teil des Zuggliedes mit dem jeweils zu verankernden Bauteil kraftschlüssig verbunden ist. Das Zugglied kann aus einem einzigen Element oder aus mehreren Elementen gebildet sein, die ihrerseits aus Stahlstäben, -drähten, -litzen oder sogar Stahlrohren bestehen können. Die Länge des Zuggliedes, über die es im Verpreßkörper eingebettet ist, wird als Verankerungslänge Lv, die restliche, zum Zwecke der Vorspannung frei dehnbare Länge als freie Stahllänge Lf bezeichnet.A grouting anchor has a tension member which is inserted into a borehole and is brought deeply into the borehole by injecting hardening material, such as cement mortar or the like, with the borehole wall and thus with the surrounding soil. This creates a compression body, which is non-positively connected to the component to be anchored in each case via the remaining part of the tension member leading to the hole in the borehole. The tension member can be formed from a single element or from several elements, which in turn can consist of steel rods, wires, strands or even steel tubes. The length of the tension member over which it is embedded in the compression body is referred to as the anchoring length L v , the remaining length, which is freely stretchable for the purpose of prestressing, as the free steel length L f .

Verpreßanker können zur dauernden Verankerung von Bauwerken im Erdreich dienen; sie können aber auch nur temporär eingesetzt werden, wie z. B. zur rückwärtigen Verankerung der Wand einer Baugrube. Wenn sich ein temporär eingesetzter Verpreßanker bis in ein Nachbargrundstück hinein erstreckt, muß er in aller Regel nach Beendigung der Bauarbeiten, für die er eingesetzt wurde, entfernt werden.Grout anchors can be used to permanently anchor structures in the ground; but they can also be used only temporarily, such as. B. for backward anchoring of the wall of an excavation pit. If a temporary grouting anchor extends into a neighboring property, it usually has to be removed after completion of the construction work for which it was used.

Zur Entfernung eines Verpreßankers wird zumeist am Übergang der Verankerungslänge Lv zur freien Stahllänge Lf eine Trennmöglichkeit für das Zugglied vorgesehen, um so den freien Teil des Zuggliedes aus dem Bohrloch herausziehen und gegebenenfalls wiedergewinnen zu können. Der Verpreßkörper selbst, der selten eine größere Länge als etwa 4 bis 8 m aufweist, kann, wenn bei Aushubarbeiten im Nachbargrundstück flächig, z. B. mit Planierraupen gearbeitet wird, meist leicht entfernt werden.To remove an injection anchor, a separating option for the tension member is usually provided at the transition from the anchoring length L v to the free steel length L f , so that the free part of the tension member can be pulled out of the borehole and possibly recovered. The grout itself, which rarely has a length greater than about 4 to 8 m, can, when excavating work in the neighboring property, e.g. B. with bulldozers, mostly easy to remove.

Von den verschiedenen Möglichkeiten zum Durchtrennen des Zugglieds eines Verpreßankers kommt der Anwendung von Wärme zur Verminderung der Festigkeit des Stahlzuggliedes größte Bedeutung zu, weil die zur Erzeugung von Wärme notwendigen Mittel ohne wesentliche Vergrößerung des Bohrlochdurchmessers mit dem Zugglied zusammen eingebaut und auch über eine größere Zeitspanne betriebsfähig gehalten werden können. Außerdem kann, wenn zur Trennung durch Verminderung seiner Festigkeit infolge Wärmeeinwirkung eine Sollbruchstelle geschaffen wird, das Zugglied während der gesamten Dauer seines Einsatzes mit seinem vollen Querschnitt ausgenützt werden.Of the various possibilities for severing the tension member of a compression anchor, the use of heat to reduce the strength of the steel tension member is of the greatest importance because the means necessary to generate heat are installed together with the tension member without a substantial increase in the borehole diameter and are also operable over a relatively long period of time can be held. In addition, if a predetermined breaking point is created for separation by reducing its strength due to the action of heat, the tension member can be used with its full cross-section for the entire duration of its use.

Zum Erzeugen der zur Verringerung der Zugfestigkeit des Zugglieds notwendigen Wärme ist es bekannt, das Zugglied im Bereich der Sollbruchstelle mittels der exothermen Reaktion, z. B. eines aluminothermischen Gemisches, zu erhitzen (FR 22 74 740). Um die exotherme Reaktion auszulösen, ist ein Zündsystem erforderlich, das in eingebautem Zustand des Ankers, der sich über eine längere Zeit erstrecken kann, nur schwer zündfähig zu halten ist.To generate the heat necessary to reduce the tensile strength of the tension member, it is known to use the tension member in the area of the predetermined breaking point by means of the exothermic reaction, e.g. B. an aluminothermic mixture to heat (FR 22 74 740). In order to trigger the exothermic reaction, an ignition system is required which is difficult to keep ignitable when the armature is installed, which can extend over a long period of time.

Es ist weiterhin bekannt, zum Erzeugen von Wärme elektrische Energie einzusetzen. Dies kann mittels eines elektrischen Heizelementes, z. B. in Form einer das Zugglied umgebenden Heizschlange geschehen (DE 24 28 729 C3) oder auch mittels einer das Zugglied an der Trennstelle umgebende Spule, die mit elektrischem Strom gespeist wird, um in dem oder den Zuggliedern durch Induktion Wärme zu erzeugen (CH 603 919). Dabei hat sich gezeigt, daß, trotz Anordnung von Wärmedämmschichten, eine zur zuverlässigen Trennung des Zugglieds ausreichende Temperatur nicht erreicht werden kann, weil ein Großteil der zugeführten Wärme schon über das Zugglied selbst durch Wärmeleitung abwandert.It is also known to use electrical energy to generate heat. This can be done by means of an electric heating element, e.g. B. in the form of a heating coil surrounding the tension member (DE 24 28 729 C3) or also by means of a coil surrounding the tension member at the point of separation, which is fed with electric current in order to generate heat in the tension member (s) by induction (CH 603 919). It has been shown that, despite the arrangement of thermal insulation layers, a reliable separation of the Tension member sufficient temperature can not be reached because a large part of the heat supplied already migrates through the tension member itself by heat conduction.

Vor diesem Hintergrund liegt der Erfindung die Aufgabe zugrunde, eine Möglichkeit zu schaffen, um durch Anwendung elektrischer Energie in möglichst kurzer Zeit im Stahlzugglied an der vorgesehenen Trennstelle ein so hohes Temperaturniveau zu erreichen, daß die Trennung zuverlässig und vollständig eintritt, so daß die freie Stahllänge ohne weiteres aus dem Bohrloch herausgezogen werden kann.Against this background, the invention has for its object to provide a way to achieve such a high temperature level by using electrical energy in the steel tension member at the intended separation point in the shortest possible time that the separation occurs reliably and completely, so that the free steel length can be easily pulled out of the borehole.

Gemäß der Erfindung wird diese Aufgabe durch die im kennzeichnenden Teil des Patentanspruchs 1 angegebenen Merkmale gelöst.According to the invention, this object is achieved by the features specified in the characterizing part of patent claim 1.

Vorteilhafte Weiterbildungen ergeben sich aus den Unteransprüchen.Advantageous further developments result from the subclaims.

Der Erfindung liegt die Erkenntnis zugrunde, daß durch Anwendung von Induktion in einem Frequenzbereich, welcher eine Übertragung der elektrischen Energie über ein handelsübliches Speisekabel zuläßt, lediglich eine Erwärmung des Zuggliedes bis zur Curie-Temperatur möglich ist, weil das ferromagnetische Material des Zuggliedes, also der Stahl, danach weitestgehend paramagnetisch wird und dadurch eine weitere Energiezufuhr durch Induktion nur noch sehr beschränkt zuläßt. Somit besteht der Grundgedanke der Erfindung darin, daß für eine Erwärmung über die Curie-Temperatur hinaus möglichst bis zum Schmelzpunkt eine zusätzliche Möglichkeit gefunden werden muß. Diese besteht gemäß der Erfindung in der Anordnung eines rohrförmigen Kerns aus elektrisch leitendem, hitzebeständigem und paramagnetischem Material, vorzugsweise aus austenitischem Stahl, zwischen der Primärwicklung und dem zu trennenden Stahlzugglied.The invention is based on the knowledge that by using induction in a frequency range which allows transmission of the electrical energy via a commercially available feed cable, only heating of the tension member up to the Curie temperature is possible because the ferromagnetic material of the tension member, i.e. the Steel, after which it becomes largely paramagnetic and therefore only permits a very limited supply of energy by induction. Thus, the basic idea of the invention is that an additional possibility must be found for heating above the Curie temperature as far as possible up to the melting point. According to the invention, this consists in the arrangement of a tubular core made of electrically conductive, heat-resistant and paramagnetic material, preferably austenitic steel, between the primary winding and the steel tension member to be separated.

Gemäß der Erfindung erfolgt die Übertragung der Leistung nach dem Induktionsprinzip im wesentlichen in zwei Phasen:

  • bis zur Curie-Temperatur, d. h. der Temperatur, bei der das Stahlzugglied vom ferromagnetischen in den paramagnetischen Bereich übergeht, erwärmt sich das Stahlzugglied aufgrund der Eindringtiefe des darin induzierten Stromes und der magnetischen Verluste durch direkten radialen Stromfluß sowie durch eine von dem rohrförmigen Kern ausgehende Wärmezufuhr;
  • oberhalb der Curie-Temperatur bis zur Schmelztemperatur des Stahlzugglieds sind überwiegend Wärmeleitung und -strahlung des rohrförmigen Kerns für den weiteren Anstieg der Temperatur im Stahlzugglied wirksam.
According to the invention, the power is transmitted essentially in two phases according to the induction principle:
  • up to the Curie temperature, i.e. the temperature at which the steel tension member changes from the ferromagnetic to the paramagnetic range, the steel tension member heats up due to the penetration depth of the current induced therein and the magnetic losses through direct radial current flow and through a supply of heat coming from the tubular core ;
  • Above the Curie temperature up to the melting temperature of the steel tension member, thermal conduction and radiation of the tubular core are predominantly effective for the further increase in the temperature in the steel tension member.

Dabei werden in der ersten Phase durch den mittelfrequenten elektrischen Strom von 5 bis 30 kHz, der mittels geeigneter Anlagen erzeugt und über Längen bis zu etwa 50 m auch noch ohne größere Verluste zur vorgesehenen Trennstelle transportiert werden kann, in dem zu trennenden Zugglied, das wie eine kurzgeschlossene Sekundärwicklung wirkt, Wirbelströme erzeugt, durch die der gesamte Querschnitt des Zugglieds gleichmäßig erwärmt wird. Dabei spielt es keine Rolle, ob der lichte Querschnitt des rohrförmigen Kerns durch das Material des Zugglieds vollständig oder nur teilweise ausgefüllt ist bzw. ob das Zugglied sich ganz oder stellenweise in wärmeleitender Verbindung zu dem rohrförmigen Kern befindet. Etwaige Zwischenräume können je nach den vorliegenden Gegebenheiten durch ein gasförmiges (z. B. Luft), flüssiges (z. B. Wasser) oder festes (z. B. Zementmörtel, Kunststoff) Medium ausgefüllt sein. Jedenfalls sollte die Eindringtiefe des elektrischen Stromes so gewählt werden, daß sie etwa bis in das Zentrum des lichten Querschnitts des rohrförmigen Kerns reicht, unabhängig davon, wo sich innerhalb dieses Querschnitts das Zugglied bzw. die Zugglieder befinden.In the first phase, the medium-frequency electrical current of 5 to 30 kHz, which can be generated by means of suitable systems and can be transported over lengths of up to about 50 m without major losses to the intended separation point, in the tension member to be separated, which is how a short-circuited secondary winding acts, eddy currents generated, through which the entire cross-section of the tension member is heated evenly. It does not matter whether the clear cross section of the tubular core is completely or only partially filled by the material of the tension member or whether the tension member is wholly or locally in heat-conducting connection to the tubular core. Depending on the circumstances, any gaps can be filled with a gaseous (e.g. air), liquid (e.g. water) or solid (e.g. cement mortar, plastic) medium. In any case, the penetration depth of the electrical current should be selected so that it extends approximately to the center of the clear cross section of the tubular core, regardless of where the tension member or the tension members are located within this cross section.

In dieser Phase wirkt der aus paramagnetischem Material bestehende rohrförmige Kern, der den Durchtritt der elektrischen Energie zum Zugglied ermöglicht, ebenfalls als kurzgeschlossene Sekundärwicklung, die sich aufgrund ihrer elektrischen Leitfähigkeit erwärmt. Weil in dieser Phase ein sehr großer Temperaturgradient besteht, kann die Wärme radial nach innen, also gegen das Zugglied abgegeben werden. Durch die hochtemperaturbeständige Wärmedämmschicht zwischen dem rohrförmigen Kern und der Primärwicklung wird verhindert, daß Wärme radial nach außen abfließt.In this phase, the tubular core made of paramagnetic material, which allows electrical energy to pass through to the tension member, also acts as a short-circuited secondary winding, which heats up due to its electrical conductivity. Because there is a very large temperature gradient in this phase, the heat can be given off radially inwards, i.e. against the tension member. The high temperature resistant thermal insulation layer between the tubular core and the primary winding prevents heat from flowing radially outwards.

In der zweiten Phase, also nach Erreichen der Curie-Temperatur, wird noch immer in gleichem Maße elektrische Energie zugeführt. Da das Zugglied in dieser Phase stark verminderte ferromagnetische Eigenschaften hat, ist der Anteil an Induktion beschränkt, so daß nur noch wenig Energie aufgenommen wird. Die in dieser Phase noch immer anstehende elektrische Energie wird fast ausschließlich in dem rohrförmigen Kern aufgrund des Transformatoreffekts in Wärme umgewandelt. Durch Wärmeleitung und Wärmestrahlung wird diese Wärme dann auf das Zugglied übertragen, so daß innerhalb der Standzeit der Spule der Schmelzpunkt erreicht werden kann.In the second phase, i.e. after the Curie temperature has been reached, electrical energy is still supplied to the same extent. Since the tension member has greatly reduced ferromagnetic properties in this phase, the proportion of induction is limited so that only little energy is consumed. The electrical energy still present in this phase is converted almost exclusively into heat in the tubular core due to the transformer effect. This heat is then transferred to the tension member by heat conduction and heat radiation, so that the melting point can be reached within the service life of the coil.

Das zur Durchtrennung des Stahlzugglieds erforderliche Temperaturniveau richtet sich einerseits nach den Materialeigenschaften des Zugglieds und andererseits nach den im Zugglied vorhandenen Spannungs- bzw. Dehnungsverhältnissen infolge von bestehenden oder aufgebrachten Zugkräften sowie nach der Größe der frei beweglichen bzw. frei dehnbaren Teillängen des Zuggliedes. Ein etwaige Zwischenräume zwischen den Einzelelementen des Zugglieds ausfüllendes Medium beeinflußt die Geschwindigkeit des Temperaturanstiegs je nach Anteil an der Querschnittsfläche unterhalb der Curie-Temperatur praktisch nicht und oberhalb der Curie-Temperatur nur geringfügig, nämlich nur dann, wenn es in fester Form und großem Anteil an der Querschnittsfläche vorliegt.The temperature level required for severing the steel tension member depends on the one hand on the material properties of the tension member and, on the other hand, on the tension or elongation conditions in the tension member as a result of existing or applied tensile forces and on the size of the freely movable or freely stretchable partial lengths of the tension member. Any space filling between the individual elements of the tension member practically influences the rate of temperature rise depending on the proportion of the cross-sectional area below the Curie temperature not and only slightly above the Curie temperature, namely only if it is in solid form and a large proportion of the cross-sectional area.

Die Grenzfälle für die Anwendung der Erfindung sind von der bestehenden mechanischen Zugspannung her einerseits durch ein schlaffes Stahlzugglied, welches zur Durchtrennung praktisch durchgeschmolzen werden muß, und andererseits durch ein rein mechanisch bis zum Bruch gespanntes Stahlzugglied gegeben, welches ohne Erwärmung im Bereich der freien Stahllänge Lf irgendwo versagt.The limit cases for the application of the invention are given by the existing mechanical tensile stress on the one hand by a slack steel tensile member, which has to be practically melted for severing, and on the other hand by a purely mechanically tensioned steel tensile member, which without heating in the area of the free steel length L. f failed somewhere.

Die Erfindung wird nachstehend anhand der Zeichnung näher erläutert. Es zeigt

Fig. 1
einen schematischen Längsschnitt durch einen Verpreßanker,
Fig. 2
einen Längsschnitt durch eine erfindungsgemäße Vorrichtung zur Bildung einer Sollbruchstelle,
Fig. 3
einen Querschnitt entlang der Linie III-III in Fig. 2,
Fig. 4
eine andere Ausführungsform der Vorrichtung nach Fig. 2 und
Fig. 5
einen Querschnitt entlang der Linie V-V in Fig. 4.
The invention is explained below with reference to the drawing. It shows
Fig. 1
2 shows a schematic longitudinal section through a compression anchor,
Fig. 2
2 shows a longitudinal section through a device according to the invention for forming a predetermined breaking point,
Fig. 3
3 shows a cross section along the line III-III in FIG. 2,
Fig. 4
another embodiment of the device of FIG. 2 and
Fig. 5
3 shows a cross section along the line VV in FIG. 4.

Fig. 1 zeigt einen Längsschnitt durch einen Verpreßanker, der aus einem Stahlzugglied 1, z. B. einem Bündel aus Stahldrahtlitzen, besteht, das in ein Bohrloch 2 eingesetzt ist. Im unteren Teil des Bohrloches 2 ist durch Einpressen von erhärtendem Material, z. B. Zementmörtel, ein Verpreßkörper 3 erzeugt. Im Verpreßkörper 3 ist das Zugglied 1 über einen Teil 1' seiner Gesamtlänge, die sogenannte Verankerungslänge Lv, verankert. Über den restlichen Teil 1'' seiner Gesamtlänge, die sogenannte freie Stahllänge Lf, ist das Zugglied 1 frei dehnbar. An der Mündung des Bohrloches 2 ist das Zugglied 1, z. B. zur Sicherung einer Baugrubenwand 4, mittels einer Verankerung 5 verankert; die Verankerung 5 ist nicht Gegenstand der Erfindung.Fig. 1 shows a longitudinal section through a compression anchor, which consists of a steel tension member 1, z. B. a bundle of steel wire strands, which is inserted into a borehole 2. In the lower part of the borehole 2 is by pressing hardening material, for. B. cement mortar, a grout 3 is generated. In the compression body 3, the tension member 1 over a part 1 'of its total length, the so-called Anchorage length L v , anchored. The tension member 1 is freely stretchable over the remaining part 1 ″ of its total length, the so-called free steel length L f . At the mouth of the borehole 2, the tension member 1, z. B. to secure a pit wall 4, anchored by an anchor 5; the anchor 5 is not the subject of the invention.

Im Bereich des überganges von der Verankerungslänge Lv zur freien Stahllänge Lf befindet sich eine Vorrichtung 6, mittels der durch Wärmeeinwirkung auf das Zugglied 1 eine Sollbruchstelle geschaffen werden kann. An dieser Sollbruchstelle ist das Zugglied 1 durchtrennbar, so daß sein sich über den Bereich der freien Stahllänge Lf erstreckender Teil 1'' aus dem Bohrloch 2 herausgezogen werden kann. Die Vorrichtung 6 kann entweder im freien Teil 1'' des Zugglieds 1, also außerhalb des Verpreßkörpers 3, liegen, sie kann aber auch - wie dargestellt - in den Verpreßkörper 3 eingebettet sein.In the area of the transition from the anchoring length L v to the free steel length L f there is a device 6 by means of which a predetermined breaking point can be created by the action of heat on the tension member 1. The tension member 1 can be severed at this predetermined breaking point, so that its part 1 ″ extending over the area of the free steel length L f can be pulled out of the borehole 2. The device 6 can either be in the free part 1 ″ of the tension member 1, that is to say outside the compression body 3, but it can also — as shown — be embedded in the compression body 3.

Wenn zusätzlich der sich über die Verankerungslänge Lv erstreckende Teil 1' des Zugglieds 1 ausgebaut werden soll, kann dieser Teil längsbeweglich durch den Verpreßkörper 3 hindurchgeführt und an dessen unterem Ende mittels geeigneter Verankerungen, z. B. einem auf Druck beanspruchten Rohr, verankert sein. In diesem Fall befindet sich die Vorrichtung 6 am unteren Ende des Zugglieds 1.If in addition the part 1 'of the tension member 1 extending over the anchoring length L v is to be removed, this part can be moved longitudinally through the pressing body 3 and at the lower end thereof by means of suitable anchoring means, e.g. B. anchored under pressure, be anchored. In this case, the device 6 is located at the lower end of the tension member 1.

Ein Ausführungsbeispiel für eine erfindungsgemäße Ausbildung der Vorrichtung 6 zur Bildung einer Sollbruchstelle ist in den Fig. 2 und 3 in Längs- und Querschnitt in größerem Maßstab dargestellt.An embodiment of an inventive design of the device 6 for forming a predetermined breaking point is shown in Figs. 2 and 3 in longitudinal and cross section on a larger scale.

Im dargestellten Ausführungsbeispiel hat die Vorrichtung 6 die Form einer Ringhülse, die auf das Zugglied 1 vor seinem Einbau in das Bohrloch 2 aufgeschoben werden kann. In ihrem Aufbau von innen nach außen besteht die Vorrichtung 6 aus einem rohrförmigen Kern aus austenitischem Stahl, dem sogenannten Trägerrohr 7, und einer darauf angeordneten hochtemperaturbeständigen Wärmedämmschicht 8. Darüber befinden sich die Windungen einer Spule 9, die wie die Primärwicklung eines Transformators wirkt. Die Spule 9 besteht vorzugsweise aus einer geradzahligen Anzahl von Lagen, z. B. aus zwei Lagen, um die zwei Phasen einer Versorgungsleitung 10 an derselben Seite der Spule 9 zur Verankerung 5 herausführen zu können. Die Windungen der Spule 9 sind hochtemperaturbeständig isoliert, z. B. zunächst mit einem Thermolack überzogen und dann mit Glasfasern umsponnen.In the illustrated embodiment, the device 6 has the shape of an annular sleeve which can be pushed onto the tension member 1 before it is installed in the borehole 2. The device 6 consists of an inside-out structure a tubular core made of austenitic steel, the so-called carrier tube 7, and a high-temperature-resistant thermal insulation layer 8 arranged thereon. Above it are the turns of a coil 9, which acts like the primary winding of a transformer. The coil 9 preferably consists of an even number of layers, e.g. B. from two layers to be able to lead the two phases of a supply line 10 on the same side of the coil 9 for anchoring 5. The turns of the coil 9 are insulated from high temperatures, e.g. B. first coated with a thermal varnish and then wound with glass fibers.

Im dargestellten Ausführungsbeispiel besteht das Zugglied 1 aus einem Bündel aus sieben einzelnen Stahldrahtlitzen 11, die im Bereich der Verankerungslänge Lv unmittelbar in den Verpreßkörper 3 eingebettet und im Bereich der freien Stahllänge Lf jeweils einzeln von Schutzrohren 12 aus Kunststoff, z. B. PE, umhüllt sind. Zur Lagesicherung oder auch zum Schutz gegen etwa eindringendes Wasser können die Zwischenräume zwischen den einzelnen Litzen 11 und der Innenwand des Trägerrohrs 7 z. B. mit Polyurethanschaum ausgefüllt sein.In the illustrated embodiment, the tension member 1 consists of a bundle of seven individual steel wire strands 11, which are embedded directly in the compression body 3 in the area of the anchoring length L v and each individually in the area of the free steel length L f of protective tubes 12 made of plastic, for. B. PE, are encased. To secure the position or to protect against water, for example, the spaces between the individual strands 11 and the inner wall of the support tube 7 z. B. filled with polyurethane foam.

Ein weiteres Ausführungsbeispiel einer erfindungsgemäßen Vorrichtung ist in Fig. 4 angedeutet. Während die Ausbildung der Vorrichtung 6 selbst derjenigen entspricht, die im Zusammenhang mit Fig. 2 beschrieben wurde, sind die Einzellitzen 11 des Zugglieds 1 hier im Bereich der freien Stahllänge Lf innerhalb eines einzigen Schutzrohres 13 angeordnet. Das zum Erzeugen des Verpreßkörpers 3 eingepreßte erhärtende Material wird durch eine Dichtung 14 am Eindringen in das Innere des Schutzrohres 13 gehindert.Another embodiment of a device according to the invention is indicated in FIG. 4. While the design of the device 6 itself corresponds to that described in connection with FIG. 2, the individual strands 11 of the tension member 1 are arranged here in the area of the free steel length L f within a single protective tube 13. The hardening material pressed in to produce the compression body 3 is prevented by a seal 14 from penetrating into the interior of the protective tube 13.

Zum Durchtrennen des Zugglieds 1 wird die Spule 9 über die Versorgungsleitung 10 mit elektrischem Strom einer Frequenz von etwa 5 bis 30 kHz und einer Spannung von etwa 500 bis 800 V beaufschlagt. Die elektrische Energie kann über eine Anlage zur Erzeugung elektrischer Energie höherer Frequenz bereitgestellt und über ein Speisekabel zugeführt werden. In Abhängigkeit von der Eindringtiefe des in dem Spannglied 1 induzierten Stromes werden hierdurch in diesem bzw. in seinen einzelnen Elementen Wirbelströme induziert, die bis zur Erreichung der Curie-Temperatur zu einer relativ raschen Aufheizung führen. Während dieser Zeit wirkt das Trägerrohr 7 aus austenitischem Stahl, ähnlich wie das Zugglied 1 selbst, als kurzgeschlossene Wicklung und erwärmt sich ebenfalls. Weil in dieser Anfangsphase ein großer Temperaturgradient besteht, wird sehr viel Wärme nach innen gegen das Spannglied 1 abgegeben; infolge der hochtemperaturbeständigen Wärmedämmung und -isolierung wird nach außen nur sehr wenig Wärme fließen. Da das Trägerrohr 7 in diesem Temperaturbereich einen geringeren Temperaturanstiegsgradienten als das Zugglied 1 aufweist, ist damit zugleich ein thermischer und mechanischer Schutz der Spule 9 gewährleistet.To cut the tension member 1, the coil 9 is supplied with electrical current of a frequency via the supply line 10 of about 5 to 30 kHz and a voltage of about 500 to 800 V. The electrical energy can be provided via a system for generating electrical energy of higher frequency and can be supplied via a feed cable. Depending on the penetration depth of the current induced in the tendon 1, eddy currents are hereby induced in this or in its individual elements, which lead to a relatively rapid heating up until the Curie temperature is reached. During this time, the support tube 7 made of austenitic steel, similar to the tension member 1 itself, acts as a short-circuited winding and also heats up. Because there is a large temperature gradient in this initial phase, a great deal of heat is emitted inwards against the tendon 1; due to the high temperature resistant thermal insulation and insulation, very little heat will flow to the outside. Since the support tube 7 has a lower temperature rise gradient than the tension member 1 in this temperature range, thermal and mechanical protection of the coil 9 is thus ensured at the same time.

Nach Erreichen der Curie-Temperatur verliert der Stahl des Zugglieds 1 seine ferromagnetischen Eigenschaften weitestgehend und verhält sich praktisch paramagnetisch. Da weiterhin elektrische Energie zugeführt wird, durch das Zugglied 1 aber nur mehr wenig verbraucht wird, steht eine größere elektrische Leistung als zuvor zur Erwärmung des nach wie vor als Sekundärspule wirkenden Trägerrohrs 7 zur Verfügung. Auf diese Weise kann die Erwärmung des Zugglieds praktisch bis zum Schmelzpunkt geführt werden. Der Grad, bis zu dem die Verringerung der Festigkeit geführt werden muß, ist abhängig von der im Zugglied 1 noch bestehenden Spannung bzw. Dehnung. Ist das Zugglied zum Zeitpunkt der Durchtrennung noch gespannt, so genügt zum Durcht rennen eine geringere Temperatur als in den Fällen, in denen das Zugglied nur mehr eine geringe Spannung aufweist oder gar spannungslos ist.After the Curie temperature has been reached, the steel of the tension member 1 largely loses its ferromagnetic properties and behaves practically paramagnetically. Since electrical energy continues to be supplied, but only a little is consumed by the tension member 1, a greater electrical output than before is available for heating the carrier tube 7, which continues to act as a secondary coil. In this way, the heating of the tension member can be carried out practically up to the melting point. The degree to which the reduction in strength must be carried out depends on the tension or elongation still existing in the tension member 1. If the tension member is still tensioned at the time of severing, a lower temperature is sufficient for cutting through than in the cases in which the tension member has only a low tension or even is without tension.

Ein Vorteil der erfindungsgemäßen Ausbildung der Vorrichtung 6 besteht noch darin, daß ihre Funktionstüchtigkeit sowie diejenige des elektrischen Speisekabels sich zu jedem Zeitpunkt durch übliche elektrische Meßverfahren überprüfen lassen. Die Vorrichtung 6 kann nur mit der entsprechenden elektrischen Anlage höherer Frequenz betätigt werden; ungewollte oder unbefugte Betätigung der Vorrichtung, wie z. B. durch fremde Energiequellen, wie Blitz, können ausgeschlossen werden.An advantage of the design of the device 6 according to the invention is that its functionality and that of the electrical feed cable can be checked at any time by conventional electrical measuring methods. The device 6 can only be operated with the corresponding electrical system of higher frequency; unwanted or unauthorized operation of the device, such as. B. by external energy sources such as lightning can be excluded.

Claims (3)

Vorrichtung zum Durchtrennen eines aus ferromagnetischem Material bestehenden Zugglieds eines Verpreßankers an einer vorgegebenen Stelle, wobei durch Verminderung seiner Zugfestigkeit in dem Zugglied eine Sollbruchstelle erzeugt wird,
mit einer, zusammen mit dem Zugglied einbaubaren, dieses an der vorgesehenen Trennstelle rohrförmig umschließenden Spule, die zum Erzeugen einer Sollbruchstelle durch Verminderung der Zugfestigkeit des Zugglieds infolge Wärmeeinwirkung durch Induktion mit elektrischem Strom beaufschlagbar ist,
dadurch gekennzeichnet, daß
die Spule (9) als Primärwicklung unter Zwischenschaltung einer hochtemperaturbeständigen Wärmedämmschicht (8) auf einem rohrförmigen Kern (7) aus elektrisch leitendem, hitzebeständigem und paramagnetischem Material angeordnet ist, wobei der Kern (7) eine erste Sekundärwicklung und das Zugglied (1) eine zweite Sekundärwicklung bilden, und die Spule (9) zum Durchtrennen des Zugglieds mit elektrischer Energie einer Frequenz von etwa 5 bis 30 kHz und einer Spannung von etwa 500 bis 800 V beaufschlagbar ist.Device for severing a tension member of a compression anchor consisting of ferromagnetic material at a predetermined point, a predetermined breaking point being generated in the tension member by reducing its tensile strength,
with a coil which can be installed together with the tension member and which surrounds it tubularly at the provided separation point and which can be subjected to electrical current by induction in order to generate a predetermined breaking point by reducing the tensile strength of the tension member due to the action of heat.
characterized in that
the coil (9) is arranged as a primary winding with the interposition of a high-temperature-resistant thermal insulation layer (8) on a tubular core (7) made of electrically conductive, heat-resistant and paramagnetic material, the core (7) having a first secondary winding and the tension member (1) a second one Form secondary winding, and the coil (9) for cutting the tension member with electrical energy of a frequency of about 5 to 30 kHz and a voltage of about 500 to 800 V can be applied. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß der rohrförmige Kern (7) aus austenitischem Stahl besteht.Device according to claim 1, characterized in that the tubular core (7) consists of austenitic steel. Vorrichtung nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß die Spule (9) eine geradzahlige Anzahl von Windungen aufweist.Device according to claim 1 or 2, characterized in that the coil (9) has an even number of turns.
EP93112845A 1992-08-17 1993-08-11 Device for separating the tension rod of a soil anchor at a provided location Expired - Lifetime EP0583725B1 (en)

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CH2555/92A CH681835A5 (en) 1992-08-17 1992-08-17
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EP (1) EP0583725B1 (en)
JP (1) JP3163207B2 (en)
AT (1) ATE133734T1 (en)
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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0721030A1 (en) * 1995-01-04 1996-07-10 DYCKERHOFF &amp; WIDMANN AG Method to make a rupture zone in a tension member for a prestressed ground anchor
WO2011116483A2 (en) 2010-03-25 2011-09-29 Stahlton Ag Device for an at least partially removable anchor and method for at least partially removing an anchor
CH702926B1 (en) * 2007-10-09 2011-10-14 Stahlton Ag Device for partial separation of pre-stressed anchor, has pre-stressed tension element and induction coil arranged on carrier pipe, which is sealed on side of separation point
WO2015127959A1 (en) 2014-02-25 2015-09-03 Vsl International Ag Removable anchor
DE202017102490U1 (en) 2017-04-27 2017-05-17 FiReP International AG Anchor arrangement in the ground as well as ground anchors
EP3321423A1 (en) 2016-11-10 2018-05-16 BAUER Spezialtiefbau GmbH Anchor arrangement in the ground, ground anchor and procedure for anchoring.

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE69420735T2 (en) * 1994-12-14 2000-03-02 Fokker Space Bv System for holding and separating construction elements
NL1007078C2 (en) * 1997-09-19 1999-03-22 Ballast Nedam Funderingstechni Towing member with failure means.
NL1015346C2 (en) * 2000-05-31 2001-12-03 Visser & Smit Bouw Bv Removal method for free anchor length of grouted anchor sunk into the ground, involves heating free anchor length to form point of weakness
JP2007262880A (en) * 2006-03-02 2007-10-11 Ats & E Co Ltd Device and method for cutting of tension member in buried anchor
JP4910142B2 (en) * 2006-10-05 2012-04-04 飛島建設株式会社 High frequency induction heating anchor removal device
JP5217054B2 (en) * 2007-03-02 2013-06-19 住友電工スチールワイヤー株式会社 Strand
JP4729690B2 (en) * 2007-03-22 2011-07-20 飛島建設株式会社 Anchor removing apparatus by high frequency induction heating and method for removing the same
JP4806370B2 (en) * 2007-04-06 2011-11-02 飛島建設株式会社 Vertical shaft construction method
JP4806375B2 (en) * 2007-05-11 2011-11-02 飛島建設株式会社 Vertical wall construction method
JP5067693B2 (en) * 2007-10-23 2012-11-07 高周波熱錬株式会社 Heating coil device and high-frequency heating device
CN110080220B (en) * 2019-05-24 2023-11-28 北京爱地地质勘察基础工程公司 Soil body anchor rod structure with heating solidification function and application method thereof
CN111042105B (en) * 2019-12-09 2021-08-17 青海民族大学 Collapsible loess foundation ditch antiskid collapse melting lead and aluminum melting plate knot support pile

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2274740A1 (en) * 1975-06-27 1976-01-09 Fischer Joachim Extraction method for steel rod ground anchors - rupture zone in rod adjacent to anchor block is formed by heating
CH603919A5 (en) * 1976-04-02 1978-08-31 Losinger Ag Releasing free section of tie anchor
DE2428729C3 (en) * 1974-06-14 1981-12-24 Philipp Holzmann Ag, 6000 Frankfurt Method for removing the tension member of a grouting anchor

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2178720A (en) * 1938-02-23 1939-11-07 Du Pont Induction heated pipe
US2948797A (en) * 1959-01-30 1960-08-09 Gen Electric Annealing furnace
US4007349A (en) * 1973-02-14 1977-02-08 John Charles Burley Inductive method for cutting cloth
JPH0255942U (en) * 1988-10-17 1990-04-23
US4916278A (en) * 1989-09-01 1990-04-10 Thermatool Corporation Severing metal strip with high frequency electrical current

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2428729C3 (en) * 1974-06-14 1981-12-24 Philipp Holzmann Ag, 6000 Frankfurt Method for removing the tension member of a grouting anchor
FR2274740A1 (en) * 1975-06-27 1976-01-09 Fischer Joachim Extraction method for steel rod ground anchors - rupture zone in rod adjacent to anchor block is formed by heating
CH603919A5 (en) * 1976-04-02 1978-08-31 Losinger Ag Releasing free section of tie anchor

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0721030A1 (en) * 1995-01-04 1996-07-10 DYCKERHOFF &amp; WIDMANN AG Method to make a rupture zone in a tension member for a prestressed ground anchor
CH702926B1 (en) * 2007-10-09 2011-10-14 Stahlton Ag Device for partial separation of pre-stressed anchor, has pre-stressed tension element and induction coil arranged on carrier pipe, which is sealed on side of separation point
WO2011116483A2 (en) 2010-03-25 2011-09-29 Stahlton Ag Device for an at least partially removable anchor and method for at least partially removing an anchor
WO2011116483A3 (en) * 2010-03-25 2012-03-08 Stahlton Ag Device for an at least partially removable anchor and method for at least partially removing an anchor
EP2998447A1 (en) 2010-03-25 2016-03-23 Stahlton AG Method for at least partially removing an anchor
WO2015127959A1 (en) 2014-02-25 2015-09-03 Vsl International Ag Removable anchor
EP3321423A1 (en) 2016-11-10 2018-05-16 BAUER Spezialtiefbau GmbH Anchor arrangement in the ground, ground anchor and procedure for anchoring.
WO2018086781A1 (en) 2016-11-10 2018-05-17 Bauer Spezialtiefbau Gmbh Anchor arrangement having ground, ground anchor, and method for anchoring
DE202017102490U1 (en) 2017-04-27 2017-05-17 FiReP International AG Anchor arrangement in the ground as well as ground anchors

Also Published As

Publication number Publication date
ATE133734T1 (en) 1996-02-15
CH681835A5 (en) 1993-05-28
CA2104146A1 (en) 1994-02-18
NO932906L (en) 1994-02-18
EP0583725B1 (en) 1996-01-31
JPH06158656A (en) 1994-06-07
DE59301539D1 (en) 1996-03-14
JP3163207B2 (en) 2001-05-08
US5389765A (en) 1995-02-14
NO932906D0 (en) 1993-08-16

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