EP0899382B1 - Anchor element for a prestressed groundanchor - Google Patents

Anchor element for a prestressed groundanchor Download PDF

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Publication number
EP0899382B1
EP0899382B1 EP98115700A EP98115700A EP0899382B1 EP 0899382 B1 EP0899382 B1 EP 0899382B1 EP 98115700 A EP98115700 A EP 98115700A EP 98115700 A EP98115700 A EP 98115700A EP 0899382 B1 EP0899382 B1 EP 0899382B1
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EP
European Patent Office
Prior art keywords
anchor element
element according
anchor
bundle
sheathing tube
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EP98115700A
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German (de)
French (fr)
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EP0899382A1 (en
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Walter Bau AG
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Walter Bau AG
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    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/74Means for anchoring structural elements or bulkheads

Definitions

  • the invention relates to an anchor element for a preferably temporary Compression anchor according to the preamble of claim 1.
  • a grouting anchor consists of an anchor element which is inserted into a borehole and deepened in the borehole by a grouting body produced by pressing in hardening material, such as cement mortar or the like, is connected to the borehole wall and thus to the surrounding soil.
  • This compression body is non-positively connected to the component to be anchored via the remaining part of the anchor element, which generally consists of a bundle of individual tension members, in particular strands made of steel wires.
  • the part of the length of the anchor element over which it is embedded in the compression body is called the composite length (L V ), the remaining part, which is freely stretchable for the purpose of prestressing, is the free steel length (L F ).
  • Grouting anchors can be used to permanently anchor structures in the ground serve, but also for temporary purposes, i.e. temporarily used, such as in particular for anchoring an excavation wall backwards. If a temporarily inserted grouting anchor into a neighboring property extends, he must often after completion of the construction work for which he is deployed was removed.
  • a separating option for the tension member is usually provided at the transition from the bonded length (L V ) to the free steel length (L F ) so that the freely stretchable part of the tension member can be pulled out of the borehole.
  • L V bonded length
  • L F free steel length
  • the tension member at the point in question is weakened before installation to create a predetermined breaking point
  • the tension member is provided with a device during installation at the separation point, with the aid of which it can be weakened after installation and use. In both cases a break is caused by the application of a tensile force that exceeds the working load.
  • Another possibility to remove the tension member is to install an empty pipe together with the tension member of the anchor in the borehole, into which an explosive charge is inserted in the area of the bond length (L V ). By igniting this explosive charge, the compression body is destroyed so that the tension member can be pulled out of the borehole with little force.
  • anchor tension members for temporary anchors are not subject to any significant corrosion stresses, they are usually not piped in the area of the free steel length (L F ).
  • L F free steel length
  • anchors made of steel wire strands are often individually strands coated with PE, which are fanned out from a relatively dense order in the area of the free steel length to the anchor head, in order to be anchored there in an anchor plate.
  • the invention is based on the object Possibility to create friction losses when clamping a to minimize the generic anchor element in the area of the free steel length and the expandability of the anchor tension member after cutting or ignition to guarantee an explosive charge in any case.
  • the basic idea of the invention is not only the individual elements of the Bundle tension member in the area of the free steel length within a surrounding to lead common cladding tube, which creates the risk of entrainment between the drill pipe and the bundle of strands when pulling the Drill pipe is reduced, but especially in that through this Cladding tube formed cavity both on the lower borehole side, and on upper air-side end of the cladding tube is sealed.
  • Fig. 1 shows a partial longitudinal section through an inventive formed anchor element 1.
  • the anchor element 1 comprises an anchor tension member 2, which is formed by a bundle of steel wire strands 3.
  • the strands 3 are bare in the area of the bond length Lv; they are here determined to be embedded in the grout.
  • the strands 3 are spread apart at certain intervals; there are at the same time spacer 4 is arranged, the centering of the tension member 2 in Effect borehole. Between the spreads in the area of the spacers 4 the strands 3 are held together by straps 5.
  • the anchor tension member 2 is surrounded by a stable cladding tube 6 made of plastic, preferably made of HDPE.
  • the cladding tube 6 extends beyond the air-side upper ends 7 of the strands 3.
  • the cladding tube 6 is sealed at the lower end 8 on the borehole side by a lower seal 9 and at the upper end 10 on the air side by an upper seal 11.
  • the anchor element 1 assembled in this way which can also have a post-grouting line 12 for injecting cement mortar into the area of the bond length L V for producing the grouting body, is lowered into a borehole in this state.
  • FIGS. 2 and 3 show a larger scale.
  • FIG. 2 shows a longitudinal section
  • FIG. 3 shows a cross section along the line III-III in FIG. 2.
  • a rigid cement mortar 14 is applied to a correspondingly large strip of a polyester nonwoven 13. This arrangement is placed under the strand bundle 2. The cement mortar is distributed around the individual strands 3 and between them by turning up the ends of the nonwoven band 13. The fleece tape 13 is then wrapped around the strand of strands 2, enclosing the cement mortar. The cladding tube 6 which has already been pushed over the area of the free steel length L F is then pushed over the cuff formed in this way.
  • the cladding tube 6 is in the area in which the polyester fleece 13 and the cement mortar 14 are heated, e.g. by a gas flame, and then in the end regions, constrictions 15 forming, each surrounded by a steel band 16. This will make the Cement mortar 14 formed into a solid plug and thus a very reliable Sealing reached.
  • the ends of the polyester fleece 13 can still by Adhesive tape 17 to be attached to the strand bundle 2.
  • the constrictions 15 create the end of the cladding tube 6 at the borehole end a tensile connection between this and the anchor tension member 2. This has the advantage that for making any length corrections to the anchor tension member 2 can also be attacked on the air-side end on the cladding tube 6 without to fear that this slides along the anchor pull member 2.
  • Anchor tension member 2 that is to say predetermined breaking point 18 arranged in the area on the strand bundle to provide the lower seal 9 because this point is particularly good there Corrosion is protected.
  • the upper seal arranged on the air-side upper end 10 of the cladding tube 6 11 can basically be designed in the same way as the lower one Seal 9. It seems particularly useful, however, the cladding tube 6 on the Let ends 7 of the strands 3 protrude. This creates the prerequisite for the fact that as a top seal 11 a plug 19 from a fixed Material such as Hardwood, fiber concrete or the like can be used.
  • the plug 19 has, as shown in Fig. 2, truncated cone-shaped Shape such that it has a thickening in the central region of its axial length 20 forms.
  • the diameter of the plug 19 becomes the diameter of the cladding tube 6 so that it is heated by the cladding tube 6 of whose front end can be driven in and by the Cooling again hardening cladding tube 6 is held in this position.
  • the plug 19 expediently has an axial bore 21 which a nipple 22 is penetrated, on the outer end of a sleeve 23 and inner end of a lock nut 24 are screwed on.
  • the opening on the sleeve 23 can be closed by a stopper 25.
  • Through the nipple 22 can Filling hose 26 are guided through which, for example, water into the Seals 9 and 11 sealed cavity of the cladding tube 6 are filled can.
  • the cavity is filled with water before the Drill hole with hardening material so as to prevent the cladding tube 6 is dented due to external pressure and so the subsequent tensioning and Removing the anchor tension member 2 is hindered.
  • the anchor element 1 is in the form described in a for example, a well drilled in the protection of a drill pipe, so that the upper end 9 of the cladding tube 6 protrudes from the borehole on the air side.
  • the individual strands 3 of the anchor tension member 2 are against influences protected from the outside, especially against the fact that when pulling the rotating Drill pipe and penetration of a water-sand mixture of the undesirable Driving and stranding effect between the drill pipe and the tension member of the Anchor can occur.
  • the water filling of the cladding tube 6 prevents Dent.
  • the cladding tube 6 is cut off at the air-side end of the anchor element, so that the ends 7 of the strand bundle 2 are accessible and anchored in the usual manner in an anchoring device can be.

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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)
  • Joining Of Building Structures In Genera (AREA)
  • Dowels (AREA)

Abstract

This is a temporary, compression anchor bolt, which includes a bundle of tensile elements, especially steel wires. The device is embedded over a connecting length Lv. A length of steel Lf, left free, is used for prestressing and is entirely surrounded by an encasing tube (6). In the new design, the tube forms a cavity surrounding the bundle (2). Seals (9, 11) close this off at the lower (8) and the exposed upper end (10). A setting material is used for sealing and there is a necking in the casing tube (6) surrounded by a tension band. Preferred materials used in the construction include cement mortar and fibre-reinforced cement. The casing is preferably plastic, especially high density polyethylene (HDPE). A fleece material (13) included, is made of plastic fibres, especially polyester.

Description

Die Erfindung betrifft ein Ankerelement für einen vorzugsweise temporären Verpreßanker gemäß dem Oberbegriff des Patentanspruchs 1.The invention relates to an anchor element for a preferably temporary Compression anchor according to the preamble of claim 1.

Ein Verpreßanker besteht aus einem Ankerelement, das in ein Bohrloch eingeführt und im Bohrlochtiefsten durch einen, durch Einpressen von erhärtendem Material, wie Zementmörtel oder dergleichen, erzeugten Verpreßkörper mit der Bohrlochwandung und so mit dem umgebenden Boden in Verbund gebracht ist. Dieser Verpreßkörper wird über den restlichen Teil des Ankerelements, das gattungsgemäß aus einem Bündel von Einzelzuggliedem, insbesondere Litzen aus Stahldrähten, besteht, mit dem zu verankernden Bauteil kraftschlüssig verbunden. Den Teil der Länge des Ankerelements, über den es im Verpreßkörper eingebettet ist, nennt man Verbundlänge (LV), den restlichen, zum Zwecke der Vorspannung frei dehnbaren Teil, freie Stahllänge (LF).A grouting anchor consists of an anchor element which is inserted into a borehole and deepened in the borehole by a grouting body produced by pressing in hardening material, such as cement mortar or the like, is connected to the borehole wall and thus to the surrounding soil. This compression body is non-positively connected to the component to be anchored via the remaining part of the anchor element, which generally consists of a bundle of individual tension members, in particular strands made of steel wires. The part of the length of the anchor element over which it is embedded in the compression body is called the composite length (L V ), the remaining part, which is freely stretchable for the purpose of prestressing, is the free steel length (L F ).

Verpreßanker können zur dauernden Verankerung von Bauwerken im Boden dienen, aber auch für vorübergehende Zwecke, also temporär eingesetzt werden, wie insbesondere zur rückwärtigen Verankerung einer Baugrubenwand. Wenn sich ein temporär eingesetzter Verpreßanker bis in ein Nachbargrundstück hinein erstreckt, muß er oftmals nach Beendigung der Bauarbeiten, für die er eingesetzt wurde, entfernt werden.Grouting anchors can be used to permanently anchor structures in the ground serve, but also for temporary purposes, i.e. temporarily used, such as in particular for anchoring an excavation wall backwards. If a temporarily inserted grouting anchor into a neighboring property extends, he must often after completion of the construction work for which he is deployed was removed.

Zur Entfernung eines temporären Verpreßankers nach Gebrauch wird meist am Übergang der Verbundlänge (LV) zur freien Stahllänge (LF) eine Trennmöglichkeit für das Zugglied vorgesehen, um so den frei dehnbaren Teil des Zugglieds aus dem Bohrloch herausziehen zu können. Zum Durchtrennen des Zugglieds eines Verpreßankers an einer vorbestimmten Stelle gibt es viele Möglichkeiten, von denen im Grunde aber nur zwei in der Praxis angewendet werden. Zum einen wird das Zugglied an der betreffenden Stelle schon vor dem Einbau geschwächt, um eine Sollbruchstelle zu erzeugen, zum anderen wird das Zugglied beim Einbau an der Trennstelle mit einer Vorrichtung versehen, mit deren Hilfe es nach Einbau und Gebrauch geschwächt werden kann. In beiden Fällen wird zum Ausbau durch Aufbringen einer die Gebrauchslast übersteigenden Zugkraft ein Bruch hervorgerufen.To remove a temporary grouting anchor after use, a separating option for the tension member is usually provided at the transition from the bonded length (L V ) to the free steel length (L F ) so that the freely stretchable part of the tension member can be pulled out of the borehole. There are many possibilities for severing the tension member of a compression anchor at a predetermined location, but only two of them are used in practice. On the one hand, the tension member at the point in question is weakened before installation to create a predetermined breaking point, on the other hand the tension member is provided with a device during installation at the separation point, with the aid of which it can be weakened after installation and use. In both cases a break is caused by the application of a tensile force that exceeds the working load.

Eine weitere Möglichkeit, das Zugglied auszubauen, besteht darin, gemeinsam mit dem Zugglied des Ankers im Bohrloch ein Leerrohr zu installieren, in das im Bereich der Verbundlänge (LV) eine Sprengladung eingeführt wird. Durch Zünden dieser Sprengladung wird der Verpreßkörper zerstört, so daß das Zugglied mit geringer Kraft aus dem Bohrloch herausgezogen werden kann.Another possibility to remove the tension member is to install an empty pipe together with the tension member of the anchor in the borehole, into which an explosive charge is inserted in the area of the bond length (L V ). By igniting this explosive charge, the compression body is destroyed so that the tension member can be pulled out of the borehole with little force.

Da Ankerzugglieder für temporäre Anker keinen nennenswerten Korrosionsbeanspruchungen unterliegen, werden diese im Bereich der freien Stahllänge (LF) üblicherweise nicht verrohrt. Um die freie Dehnbarkeit zu sichern, werden bei Ankern aus Stahldrahtlitzen oft einzeln mit PE ummantelte Litzen verwendet, die von einer relativ dichten Ordnung im Bereich der freien Stahllänge zum Ankerkopf hin aufgefächert werden, um dort in einer Ankerplatte verankert zu werden.Since anchor tension members for temporary anchors are not subject to any significant corrosion stresses, they are usually not piped in the area of the free steel length (L F ). To ensure free ductility, anchors made of steel wire strands are often individually strands coated with PE, which are fanned out from a relatively dense order in the area of the free steel length to the anchor head, in order to be anchored there in an anchor plate.

Insbesondere dann, wenn die Bohrlöcher für solche Anker unterhalb des Grundwasserspiegels unter Einsatz eines Bohrrohres gebohrt werden, durch das nach dem Einsetzen des Ankerelements im Bereich der Verbundlänge (LV) verpreßt und im Bereich der freien Stahllänge (LF) verfüllt wird, besteht beim Ziehen des Bohrrohres kurz vor dessen Austritt aus dem Bohrloch, also in einem sehr diffizilen Bereich des Ankers kurz vor der Verankerung, die Gefahr, daß in das Bohrloch bzw. in das noch im Ziehen befindliche Bohrrohr ein Wasser-Boden-Gemisch eindringt, das eine so hohe innere Reibung hat, daß das beim drehenden Ziehen des Bohrrohres auftretende Drehmoment auf das Litzenbündel übertragen wird. Hierdurch können sich diese Litzen so verseilen, daß im Ankerzugglied unverhältnismäßig hohe Reibungswiderstände auftreten, so daß die Litzen des Ankerzugglieds nicht ordnungsgemäß gespannt bzw. nach Gebrauch nicht mit Sicherheit ausgebaut werden können. In particular, if the drill holes for such anchors are drilled below the water table using a drill pipe through which, after inserting the anchor element, the area is pressed in the area of the bonded length (L V ) and filled in the area of the free steel length (L F ) Pulling the drill pipe shortly before it emerges from the borehole, i.e. in a very difficult area of the anchor shortly before anchoring, there is a risk that a water-soil mixture will penetrate into the drill hole or into the drill pipe that is still being pulled internal friction is so high that the torque that occurs when the drill pipe is pulled while rotating is transmitted to the bundle of strands. As a result, these strands can strand so that disproportionately high frictional resistances occur in the anchor pull member, so that the strands of the anchor pull member cannot be properly tensioned or cannot be removed with certainty after use.

In diesem Zusammenhang ist auch der allgemeine Gedanke bekannt, das Litzenbündel eines temporären Ankers im Bereich der freien Stahllänge durch ein Hüllrohr gegen den es umgebenden Boden und gegen das den Verpreßkörper bildende Verpreßmaterial abzuschirmen (AT 360 431).In this context, the general idea that the Strand bundle of a temporary anchor in the area of the free steel length through a Cladding tube against the surrounding soil and against the grout shielding grouting material (AT 360 431).

Vor diesem Hintergrund liegt der Erfindung die Aufgabe zugrunde, eine Möglichkeit zu schaffen, um die Reibungsverluste beim Spannen eines gattungsgemäßen Ankerelements im Bereich der freien Stahllänge zu minimieren und die Ausbaubarkeit des Ankerzugglieds nach Durchtrennung bzw. Zünden einer Sprengladung in jedem Fall zu gewährleisten.Against this background, the invention is based on the object Possibility to create friction losses when clamping a to minimize the generic anchor element in the area of the free steel length and the expandability of the anchor tension member after cutting or ignition to guarantee an explosive charge in any case.

Gemäß der Erfindung wird diese Aufgabe durch die im Anspruch 1 angegebenen Merkmale gelöst.According to the invention, this object is achieved by those specified in claim 1 Features solved.

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

Der Grundgedanke der Erfindung besteht nicht nur darin, die Einzelelemente des Bündelzugglieds im Bereich der freien Stahllänge innerhalb eines sie umgebenden gemeinsamen Hüllrohres zu führen, wodurch die Gefahr des Mitnahmeeffektes zwischen dem Bohrrohr und dem Litzenbündel bei dem drehenden Ziehen des Bohrrohres vermindert wird, sondern vor allem darin, daß der durch dieses Hüllrohr gebildete Hohlraum sowohl am unteren bohrlochseitigen, als auch am oberen luftseitigen Ende des Hüllrohrs dichtend abgeschlossen ist. Dadurch wird einerseits verhindert, daß in diesen Hohlraum etwa Teile des zum Teil unter hohem Druck eingepreßten erhärtenden Materials eindringen und das Spannen bzw. nachträgliche Herausziehen der Einzelelemente erschweren oder gar verhindern können, als auch ermöglicht, daß der Hohlraum des Hüllrohrs während des Injizierens des Bohrloches mit einer inkompressiblen Flüssigkeit, insbesondere Wasser, gefüllt werden kann, um so ein etwaiges Einbeulen des Hüllrohrs unter dem Injizierdruck zu verhindern, das zu einer Blockierung des Litzenbündels führen und das Spannen bzw. nachträgliche Entnehmen der Einzelelemente behindern könnte. The basic idea of the invention is not only the individual elements of the Bundle tension member in the area of the free steel length within a surrounding to lead common cladding tube, which creates the risk of entrainment between the drill pipe and the bundle of strands when pulling the Drill pipe is reduced, but especially in that through this Cladding tube formed cavity both on the lower borehole side, and on upper air-side end of the cladding tube is sealed. This will on the one hand prevents that parts of the part under in this cavity high pressure injected hardening material penetrate and tightening or subsequent removal of the individual elements complicate or even can prevent, as well as allows the cavity of the cladding tube during injecting the borehole with an incompressible liquid, especially water, can be filled, so as to prevent any denting of the Cladding tube under the injection pressure to prevent it from blocking of the strand bundle and the tensioning or subsequent removal of the Could hinder individual elements.

Durch die Herstellung zumindest der unteren, bohrlochseitigen Dichtung aus einem erhärtenden Material, das durch Einschnürungen an den Enden der Dichtung eng umschlossen ist, entsteht eine zugfeste Verbindung zwischen dem Ankerzugglied und dem Hüllrohr. Dies hat den Vorteil, daß bei allfälligen Längenkorrekturen des Ankerzugglieds am luftseitigen Ende auch an dem Hüllrohr angegriffen werden kann, ohne befürchten zu müssen,, daß dieses an dem Ankerzugglied entlanggleitet.By producing at least the lower, borehole-side seal a hardening material that is constricted at the ends of the Seal is tightly enclosed, a tensile connection is created between the Anchor tension member and the cladding tube. This has the advantage that in the event of any Length corrections of the anchor tension member at the air end also on the cladding tube can be attacked without fear, that this on the Anchor tension member slides along.

Weitere Merkmale der Erfindung, insbesondere die gegenständliche Ausbildung der unteren und oberen Dichtung ergeben sich aus der nachstehenden Beschreibung eines in der Zeichnung dargestellten Ausführungsbeispiels. Es zeigt

Fig. 1
einen teilweisen Längsschnitt durch ein Ankerelement gemäß der Erfindung,
Fig. 2
einen Längsschnitt durch den Bereich der freien Stahllänge (LF) des Ankerelements in größerem Maßstab und
Fig. 3
einen Querschnitt entlang der Linie III-III in Fig. 2.
Further features of the invention, in particular the objective design of the lower and upper seal, result from the following description of an exemplary embodiment shown in the drawing. It shows
Fig. 1
a partial longitudinal section through an anchor element according to the invention,
Fig. 2
a longitudinal section through the area of the free steel length (L F ) of the anchor element on a larger scale and
Fig. 3
a cross-section along the line III-III in Fig. 2nd

Fig. 1 zeigt einen teilweisen Längsschnitt durch ein erfindungsgemäß ausgebildetes Ankerelement 1. Das Ankerelement 1 umfaßt ein Ankerzugglied 2, das durch ein Bündel aus Stahldrahtlitzen 3 gebildet ist.Fig. 1 shows a partial longitudinal section through an inventive formed anchor element 1. The anchor element 1 comprises an anchor tension member 2, which is formed by a bundle of steel wire strands 3.

Im Bereich der Verbundlänge Lv liegen die Litzen 3 blank; sie sind hier dazu bestimmt, in den Verpreßkörper eingebettet zu werden. Um die Verbundwirkung der aus glatten Stahldrähten bestehenden Litzen 3 in dem aus erhärtetem Material, insbesondere Zementmörtel, bestehenden Verpreßkörper zu erhöhen, sind die Litzen 3 in bestimmten Abständen voneinander gespreizt; dort sind zugleich Abstandhalter 4 angeordnet, die eine Zentrierung des Zugglieds 2 im Bohrloch bewirken. Zwischen den Spreizungen im Bereich der Abstandhalter 4 sind die Litzen 3 durch Umschnürungen 5 zusammengehalten.The strands 3 are bare in the area of the bond length Lv; they are here determined to be embedded in the grout. To the compound effect of the existing strand 3 made of smooth steel wires in the hardened Material, especially cement mortar, to increase the existing grout, the strands 3 are spread apart at certain intervals; there are at the same time spacer 4 is arranged, the centering of the tension member 2 in Effect borehole. Between the spreads in the area of the spacers 4 the strands 3 are held together by straps 5.

Im Bereich der freien Stahllänge LF ist das Ankerzugglied 2 von einem stabilen Hüllrohr 6 aus Kunststoff, vorzugsweise aus HDPE, umgeben. Das Hüllrohr 6 reicht über die luftseitigen oberen Enden 7 der Litzen 3 hinaus. Das Hüllrohr 6 ist am bohrlochseitigen unteren Ende 8 durch eine untere Dichtung 9 sowie am luftseitigen oberen Ende 10 durch eine obere Dichtung 11 dichtend verschlossen. Das so zusammengestellte Ankerelement 1, das auch noch eine Nachverpreßleitung 12 zum Injizieren von Zementmörtel in den Bereich der Verbundlänge LV zur Herstellung des Verpreßkörpers aufweisen kann, wird in diesem Zustand in ein Bohrloch abgesenkt.In the area of the free steel length L F , the anchor tension member 2 is surrounded by a stable cladding tube 6 made of plastic, preferably made of HDPE. The cladding tube 6 extends beyond the air-side upper ends 7 of the strands 3. The cladding tube 6 is sealed at the lower end 8 on the borehole side by a lower seal 9 and at the upper end 10 on the air side by an upper seal 11. The anchor element 1 assembled in this way, which can also have a post-grouting line 12 for injecting cement mortar into the area of the bond length L V for producing the grouting body, is lowered into a borehole in this state.

Die Ausbildung des Ankerelements 1 im Bereich der freien Stahllänge LF ist in den Fig. 2 und 3 in größerem Maßstab dargestellt. Fig. 2 zeigt einen Längsschnitt, Fig. 3 einen Querschnitt entlang der Linie III-III in Fig. 2.The formation of the anchor element 1 in the area of the free steel length L F is shown in FIGS. 2 and 3 on a larger scale. FIG. 2 shows a longitudinal section, FIG. 3 shows a cross section along the line III-III in FIG. 2.

Wesentlich für die Erfindung ist nicht nur die Ausgestaltung, sondern vor allem auch die Art und Weise der Herstellung der Dichtungen 9 und 11, damit sie wirklich einen dichten Anschluß des innerhalb des Hüllrohrs 6 gebildeten Hohlraums gewährleisten. Dies ist besonders schwierig dort, wo das Hüllrohr 6 das Ankerzugglied 2 umschließt, wo also auch die Zwischenräume zwischen den einzelnen Litzen 3 sowie der Ringraum zwischen dem Litzenbündel und der Innenwand des Hüllrohrs 6 abgedichtet werden muß. Als Dichtungen können in an sich bekannter Weise mit Zementmörtel injizierbare Packer zum Beispiel aus einem Polyestervlies dienen. Besonders vorteilhaft erscheint aber ein Dichtungsaufbau, wie er anhand der Herstellung der unteren Dichtung 9 erläutert werden kann.It is not only the design that is essential for the invention, but above all also the way of making the seals 9 and 11 so that they really a tight connection of the formed within the cladding tube 6 Ensure cavity. This is particularly difficult where the cladding tube 6 encloses the anchor tension member 2, so where the spaces between the individual strands 3 and the annular space between the strand bundle and the Inner wall of the cladding tube 6 must be sealed. As seals can in packers injectable with cement mortar, for example serve a polyester fleece. However, one appears to be particularly advantageous Seal structure, as explained using the manufacture of the lower seal 9 can be.

Zur Herstellung der unteren Dichtung 9 wird auf einen entsprechend großen Streifen eines Polyestervlieses 13 ein steifer Zementmörtel 14 aufgetragen. Diese Anordnung wird unter das Litzenbündel 2 gebracht. Durch Hochschlagen der Enden des Vliesbandes 13 wird der Zementmörtel um die einzelnen Litzen 3 und zwischen diesen verteilt. Das Vliesband 13 wird dann, den Zementmörtel umschließend, um das Litzenbündel 2 herumgewickelt. Über die so gebildete Manschette wird sodann das zuvor schon über den Bereich der freien Stahllänge LF geschobene Hüllrohr 6 geschoben.To produce the lower seal 9, a rigid cement mortar 14 is applied to a correspondingly large strip of a polyester nonwoven 13. This arrangement is placed under the strand bundle 2. The cement mortar is distributed around the individual strands 3 and between them by turning up the ends of the nonwoven band 13. The fleece tape 13 is then wrapped around the strand of strands 2, enclosing the cement mortar. The cladding tube 6 which has already been pushed over the area of the free steel length L F is then pushed over the cuff formed in this way.

Noch bevor der Zementmörtel 14 erstarrt, wird das Hüllrohr 6 in dem Bereich, in dem sich das Polyestervlies 13 und der Zementmörtel 14 befinden, angewärmt, z.B. durch eine Gasflamme, und dann in den Endbereichen, Einschnürungen 15 bildend, jeweils von einem Stahlband 16 umschlossen. Dadurch wird der Zementmörtel 14 zu einem festen Pfropfen geformt und so eine sehr zuverlässige Abdichtung erreicht. Die Enden des Polyestervlieses 13 können noch durch ein Klebeband 17 am Litzenbündel 2 befestigt werden.Even before the cement mortar 14 solidifies, the cladding tube 6 is in the area in which the polyester fleece 13 and the cement mortar 14 are heated, e.g. by a gas flame, and then in the end regions, constrictions 15 forming, each surrounded by a steel band 16. This will make the Cement mortar 14 formed into a solid plug and thus a very reliable Sealing reached. The ends of the polyester fleece 13 can still by Adhesive tape 17 to be attached to the strand bundle 2.

Durch die Einschnürungen 15 entsteht am bohrlochseitigen Ende des Hüllrohrs 6 eine zugfeste Verbindung zwischen diesem und dem Ankerzugglied 2. Dies hat den Vorteil, daß zur Vornahme allfälliger Längenkorrekturen des Ankerzugglieds 2 am luftseitigen Ende auch an dem Hüllrohr 6 angegriffen werden kann, ohne befürchten zu müssen, daß dieses an dem Ankerzugglied 2 entlanggleitet.The constrictions 15 create the end of the cladding tube 6 at the borehole end a tensile connection between this and the anchor tension member 2. This has the advantage that for making any length corrections to the anchor tension member 2 can also be attacked on the air-side end on the cladding tube 6 without to fear that this slides along the anchor pull member 2.

Wenn es sich bei dem Ankerelement für einen temporären Verpreßanker um einen ausbaubaren Anker mit Sollbruchstelle handelt, dann ist es sinnvoll, die am Ankerzugglied 2, also am Litzenbündel angeordnete Sollbruchstelle 18 im Bereich der unteren Dichtung 9 vorzusehen, weil diese Stelle dort besonders gut gegen Korrosion geschützt ist.If it is the anchor element for a temporary grouting anchor a removable anchor with a predetermined breaking point, then it makes sense to Anchor tension member 2, that is to say predetermined breaking point 18 arranged in the area on the strand bundle to provide the lower seal 9 because this point is particularly good there Corrosion is protected.

Die am luftseitigen oberen Ende 10 des Hüllrohrs 6 angeordnete obere Dichtung 11 kann grundsätzlich in der gleichen Weise ausgebildet sein wie die untere Dichtung 9. Besonders zweckmäßig erscheint es aber, das Hüllrohr 6 über die Enden 7 der Litzen 3 hinausragen zu lassen. Dies schafft die Voraussetzung dafür, daß als obere Dichtung 11 ein Verschlußpfropfen 19 aus einem festen Material, wie z.B. Hartholz, Faserbeton oder dergleichen, verwendet werden kann. The upper seal arranged on the air-side upper end 10 of the cladding tube 6 11 can basically be designed in the same way as the lower one Seal 9. It seems particularly useful, however, the cladding tube 6 on the Let ends 7 of the strands 3 protrude. This creates the prerequisite for the fact that as a top seal 11 a plug 19 from a fixed Material such as Hardwood, fiber concrete or the like can be used.

Der Verschlußpfropfen 19 hat, wie in Fig. 2 dargestellt, doppelkegelstumpfförmige Gestalt derart, daß er im mittleren Bereich seiner axialen Länge eine Verdickung 20 bildet. Der Durchmesser des Verschlußpfropfens 19 wird auf den Durchmesser des Hüllrohrs 6 so abgestimmt, daß er nach Erwärmung des Hüllrohrs 6 von dessen stirnseitigem Ende her eingeschlagen werden kann und durch das beim Abkühlen wieder erhärtende Hüllrohr 6 in dieser Lage festgehalten wird.The plug 19 has, as shown in Fig. 2, truncated cone-shaped Shape such that it has a thickening in the central region of its axial length 20 forms. The diameter of the plug 19 becomes the diameter of the cladding tube 6 so that it is heated by the cladding tube 6 of whose front end can be driven in and by the Cooling again hardening cladding tube 6 is held in this position.

Der Verschlußpfropfen 19 weist zweckmäßig eine axiale Bohrung 21 auf, die von einem Nippel 22 durchsetzt wird, auf den am äußeren Ende eine Muffe 23 und am inneren Ende eine Gegenmutter 24 aufgeschraubt sind. Die Öffnung an der Muffe 23 ist durch einen Stopfen 25 verschließbar. Durch den Nippel 22 kann ein Füllschlauch 26 geführt werden, durch den zum Beispiel Wasser in den durch die Dichtungen 9 und 11 abgedichteten Hohlraum des Hüllrohrs 6 eingefüllt werden kann. Die Füllung des Hohlraums mit Wasser erfolgt vor dem Auspressen des Bohrloches mit erhärtendem Material, um so zu verhindern, daß das Hüllrohr 6 infolge äußeren Drucks eingebeult wird und so das nachträgliche Spannen und Ausbauen des Ankerzugglieds 2 behindert wird.The plug 19 expediently has an axial bore 21 which a nipple 22 is penetrated, on the outer end of a sleeve 23 and inner end of a lock nut 24 are screwed on. The opening on the sleeve 23 can be closed by a stopper 25. Through the nipple 22 can Filling hose 26 are guided through which, for example, water into the Seals 9 and 11 sealed cavity of the cladding tube 6 are filled can. The cavity is filled with water before the Drill hole with hardening material so as to prevent the cladding tube 6 is dented due to external pressure and so the subsequent tensioning and Removing the anchor tension member 2 is hindered.

Das erfindungsgemäße Ankerelement 1 wird in der beschriebenen Form in ein zum Beispiel im Schutze eines Bohrrohres abgeteuftes Bohrloch eingeführt, so daß das obere Ende 9 des Hüllrohrs 6 luftseitig aus dem Bohrloch herausragt. Durch das Hüllrohr 6 sind die Einzellitzen 3 des Ankerzugglieds 2 gegen Einflüsse von außen geschützt, insbesondere dagegen, daß beim drehenden Ziehen des Bohrrohres und Eindringen eines Wasser-Sand-Gemisches der unerwünschte Mitnahme- und Verseilungseffekt zwischen dem Bohrrohr und dem Zugglied des Ankers auftreten kann. Die Wasserfüllung des Hüllrohrs 6 verhindert ein Einbeulen.The anchor element 1 according to the invention is in the form described in a for example, a well drilled in the protection of a drill pipe, so that the upper end 9 of the cladding tube 6 protrudes from the borehole on the air side. Through the cladding tube 6, the individual strands 3 of the anchor tension member 2 are against influences protected from the outside, especially against the fact that when pulling the rotating Drill pipe and penetration of a water-sand mixture of the undesirable Driving and stranding effect between the drill pipe and the tension member of the Anchor can occur. The water filling of the cladding tube 6 prevents Dent.

Nach dem Verpressen der Verbundlänge LV sowie Verfüllen des Bereichs der freien Stahllänge LF und Erhärten des Zementmörtels wird am luftseitigen Ende des Ankerelements das Hüllrohr 6 abgetrennt, so daß die Enden 7 des Litzenbündels 2 zugänglich werden und in üblicher Weise in einer Verankerungsvorrichtung spannbar verankert werden können.After pressing the composite length L V and filling the area of the free steel length L F and hardening the cement mortar, the cladding tube 6 is cut off at the air-side end of the anchor element, so that the ends 7 of the strand bundle 2 are accessible and anchored in the usual manner in an anchoring device can be.

Claims (11)

  1. An anchor element for a preferably temporary pressure-grouted anchor, in which the anchor tension member comprises a bundle of individual tension members, in particular strands of steel wire, which along the bond length (LV) are embedded in a pressure-grouted body and are freely extensible along the free length (LF), wherein along the free length (LF) the tension member is surrounded completely by a sheathing tube, characterised in that the cavity formed by the sheathing tube (6) and enclosing the tension member (2) is sealed fluidtightly both at its lower end (8) on the borehole side and at its external upper end (10) by seals (9,11), wherein at least in the annular space formed between the bundle of individual tension members (3) and the sheathing tube (6) the lower seal (9) and/or the upper seal (11) consist of a material which sets, and at both ends at least of the lower seal (9) the sheathing tube (6) is tightly enclosed respectively by a taut band (16) forming constrictions (15) of the sheathing tube (6).
  2. An anchor element according to Claim 1, characterised in that the lower seal (9) and/or the upper seal (11) comprise a packing bag of non-woven fabric, which surrounds the bundle (2) and which can be injected with a material which sets, in particular cement mortar.
  3. An anchor element according to Claim 2, characterised in that the spaces between the individual elements of the bundle in the vicinity of the seal are filled with a sealing material.
  4. An anchor element according to Claim 1, characterised in that the lower seal (9) consists of a layer (14) of a material which sets, in particular cement mortar, surrounding the individual elements (3) of the bundle (2), which layer is enclosed by a layer (13) of non-woven fabric adjacent the inner wall of the sheathing tube.
  5. An anchor element according to Claim 1 or according to Claims 3 or 4, characterised in that the upper seal (11) comprises a plug (19) of a solid material, for example hardened fibrous concrete.
  6. An anchor element according to Claim 5, characterised in that the plug (19) is of double frustoconical shape.
  7. An anchor element according to Claim 5 or 6, characterised in that the plug (19) has an axial bore (21) through which passes a nipple (22) leading into the cavity of the sheathing tube (6).
  8. An anchor element according to Claim 7, characterised in that an inlet duct, e.g. for water, is passed through the nipple (22).
  9. An anchor element according to any one of Claims 1 to 8, characterised in that at the external end the sheathing tube (6) projects beyond the end (7) of the bundle (2), and in that the upper seal (11) is disposed in the projecting portion.
  10. An anchor element according to any one of Claims 1 to 9, characterised in that the sheathing tube (6) consists of plastics material, in particular of HDPE.
  11. An anchor element according to any one of Claims 1 to 10, characterised in that the non-woven fabric (13) consists of plastics fibres, in particular of polyester.
EP98115700A 1997-08-27 1998-08-20 Anchor element for a prestressed groundanchor Expired - Lifetime EP0899382B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE29715363U 1997-08-27
DE29715363U DE29715363U1 (en) 1997-08-27 1997-08-27 Anchor element for a grout anchor

Publications (2)

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EP0899382A1 EP0899382A1 (en) 1999-03-03
EP0899382B1 true EP0899382B1 (en) 2002-04-03

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Application Number Title Priority Date Filing Date
EP98115700A Expired - Lifetime EP0899382B1 (en) 1997-08-27 1998-08-20 Anchor element for a prestressed groundanchor

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EP (1) EP0899382B1 (en)
AT (1) ATE215645T1 (en)
DE (2) DE29715363U1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019140492A1 (en) * 2018-01-22 2019-07-25 Garock Pty Ltd Improvements in or relating to rock bolts

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE29911830U1 (en) 1999-07-07 1999-09-30 Suspa Spannbeton Gmbh, 40764 Langenfeld Strand-shaped tension element, especially for construction technology
CN100453743C (en) * 2006-06-05 2009-01-21 吴德兴 Prestress anchor device

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Publication number Priority date Publication date Assignee Title
CH583340A5 (en) 1974-06-19 1976-12-31 Losinger Ag
DE2511863C3 (en) * 1975-03-18 1980-01-03 Dyckerhoff & Widmann Ag, 8000 Muenchen Corrosion-protected tension member for a prestressed grouting anchor
DE3116619C2 (en) * 1981-04-27 1983-07-28 Josef 6943 Birkenau Compernaß Grouting anchors, especially permanent anchors
DE3431211A1 (en) * 1984-08-24 1986-03-06 Stump Bohr Gmbh, 8045 Ismaning Multi-steel anchor
EP0220161B1 (en) * 1985-08-26 1990-04-25 Vorspann-Technik Gesellschaft m.b.H. Anchor, especially a free-play anchor
DE3844417C2 (en) * 1988-12-30 1995-02-16 Tgb Technogrundbau Gmbh Process for producing a re-tensionable compression anchor with permanent corrosion protection, and compression anchor manufactured thereby

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019140492A1 (en) * 2018-01-22 2019-07-25 Garock Pty Ltd Improvements in or relating to rock bolts

Also Published As

Publication number Publication date
DE29715363U1 (en) 1997-11-27
DE59803589D1 (en) 2002-05-08
ATE215645T1 (en) 2002-04-15
EP0899382A1 (en) 1999-03-03

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