EP1533471A1 - Yieldable rock anchor - Google Patents

Abstract

The sliding anchor, in particular, in the form of a self-drilling injection anchor comprises an anchor head (16) which is provided with one or several pin-shaped, adjustable elements (24) for engagement with the external thread (22) on the anchor rod (7).

Description

The present invention relates to a sliding anchor, in particular self-drilling Gleitinjektionsanker, comprising at least one with external thread provided anchor rod and at least one Gleitankerkopf along the Anchor rod is displaceable overcoming a sliding resistance.

Such sliding anchors are used in the construction of cavities in particular depressing mountains. It may be the removal of rock loads around the cavity, depending on the mechanical properties of the subsoil due to stress redistributions to excess strength come with, i. d. R. comparatively far in subsoil-related shifts. At one here possible cavity protection by means of compliant shoring can accordingly sliding linings of the cavity with said Sliding anchors are anchored, with a tearing of the sliding anchor head by its displaceability in overcoming a limit load along the first is avoided in the cavity projecting anchor head bar.

A sliding anchor of the type mentioned is known from DE 3507089 A1. According to the operation described there, the sliding resistance, i. the limit load of the sliding anchor, when they reach or exceed the Slide anchor head is slidable on the anchor rod, through a multi-stage Cutting the external thread of the anchor rod by the Gleitankerkopf generated. The required cutting edges are on separate cutting segments provided, which is conical for mounting the Gleitankerkopfes whose housing can be pressed in. This means that after positioning the Gleitankerkopfes still to achieve the required sliding resistance with the pressing of the cutting segments on the site another step necessary is. In a variant also described are the Cutting edges formed directly in the housing of Gleitankerkopfes, but no (pre-) setting a desired sliding resistance is possible. The known variants have in common that on the one hand comparatively complicated production of Gleitankerkopfes also the There is a risk that the cutting, i. also the sliding resistance, by a Tilting of the anchor head and wear of the cutting edges adversely affected.

On this basis, the object of the present invention is to provide a sliding anchor of the type mentioned production and technical use to develop advantageous.

This task is initially and essentially solved in the subject matter of Claim 1, wherein it is stated that the Gleitankerkopf on or several pin-like, to an engagement in the external thread to unscrew of the sliding anchor head has engagement elements adapted to the anchor rod, wherein the intervention when exceeding a certain sliding resistance, i.e. when reaching a limit load, to achieve the slidability is compliant. According to the invention, a sliding anchor is created, the Gleitankerkopf itself for positioning and possibly to bias the Sliding anchor on the anchor rod can be easily screwed, the Function of an overload protection due to mobility when exceeded a limit load from the beginning, i. without additional work, for Is available and also a simple, thereby inexpensive and robust Construction is possible. The term "pin-like" stands for design forms, which allow threaded engagement at the thread periphery, such as pins with round or polygonal cross-section, with further possible conical, rounded or continuous cross-section pin end. Also conceivable would be, for example, a ball or the like, in the Gleitankerkopf is suitably held for engagement in the external thread. The inventive Compliance can in principle on the one hand on the part of the engagement element exist that, for example, resiliently against the thread ribs of the external thread the anchor rod can be employed. On the other hand, under the Invention preferred that the said compliance on the part of the external thread the anchor rod is provided. There is the possibility that the engagement element when exceeding the certain sliding resistance of the Sliding anchor head, i. upon reaching a predetermined limit load of Gleitankers, with its engaging in the external thread engagement profile for Achieving the compliant engagement a displacement of the external thread e-rib causes. The displacement is preferably achieved in that a Engaging element with respect to the external thread higher skill or Has hardness and overcoming the predetermined sliding resistance by reaching the ultimate load of the sliding anchor for plowing or shear through the male thread rib in anchor longitudinal direction through the engagement profile comes. By the defined flexibility first an elastic Deformation and then a flow of the material of the outer thread rib underlying, the advantage is achieved over a machining, that wear is practically impossible and even tilting of the Thread engagement is hardly of influence. It adds that the thread groove the external thread following the displaced threaded rib, sufficient Space to accommodate the displaced amount of material provides, so no consuming separate Abfuhrnuten are necessary. Another advantage the invention is that the sliding anchor head in a variety of ways to a certain desired sliding resistance on the anchor rod customizable is, in particular in the form that the sliding resistance variably adjustable is. First, there is the possibility that, for example, to determine the Range (such as low, medium or high limit load) is an appropriate Number of engagement elements on the slide anchor head for engagement in the external thread is arranged. In accordance with several, at the same time at the same outer thread flank adjacent engagement elements this means that when crossing the particular, on the Gleitankerkopf total related sliding resistance with their respective engagement profile also respectively cause a displacement of the outer thread rib, i. the sliding resistance consists of the displacement resistance of the multiple engagement elements together. Alternatively or in combination, there is the possibility that the depth of engagement the or an engagement element in the external thread adjustable, in particular continuously adjustable, is. For this purpose, for example, the engagement element in the slider anchor an assigning to the anchor rod Pass through hole and held longitudinally adjustable by adjusting thread and preferably be lockable with a lock nut. In this way can a comparatively low sliding resistance by a smaller engagement depth and a comparatively higher sliding resistance by a larger one Insertion depth can be adjusted. It is preferred that the depth of engagement of the Engagement element in the external thread about the same or slightly smaller than the Thread depth of the external thread is. This ensures that by the displacement effect the engagement element in the longitudinal direction in the anchor rod no continuous groove is created, so the risk of material jams and undesirably increasing sliding resistance is avoided. Also, if the depth of engagement is about the same or slightly smaller than the thread depth safer, less sensitive to manufacturing tolerances and tilting Intervention achieved. A setting of the sliding resistance is finally in the Ways of suitable adaptation of the profile width of the engagement element, i. For example, the cross-sectional diameter, possible.

An expedient design of the sliding anchor can according to the invention also are that in Gleitankerlängsrichtung the thread rib distance of External thread with a corresponding cross-sectional position greater than the extension of the engagement element, wherein the thread rib spacing is preferred about two to three times the extension of the engagement element in the longitudinal direction can amount. On the one hand, this makes the recording room in proportion increased to the repressed material, on the other can be at give the advantage over the sliding anchor uniform external thread advantage that the shear strength of a mortar of the anchor is improved. It is further preferred that the sliding anchor head at least two engagement elements having, with respect to the external thread of the anchor rod in each other Unequal phase position are kept, so that in Gleitankerlängsrichtung a Overall virtually play-free engagement of the sliding anchor head in the external thread the anchor rod is obtained. Thus, for example, two engagement elements, which have at their engagement end cone tips, so on the Gleitankerkopf be held that the apex of the first engagement element on the a (for example, left) thread flank of the external thread and the cone tip the second engagement element on the respect. Of the thread curve other (i.e., then, for example, right) thread flank abuts. In a plurality of engagement elements can the profile cross section and the distance between the External thread rib (s) and the number, phase and engagement profile of Engagement elements be tuned so that at any time at least one of the engagement elements in loading direction in plant or displacement position is located to the external thread rib, so that the sliding resistance along the Gleitweges is consistently effective. This can be useful provided be that the thread rib of the external thread has a substantially trapezoidal Cross-section, wherein the lateral trapezoidal flanks in particular turn rounded into the thread root. The foot of the Trapezoidal flanks can thus depending on the shape of the engagement end of the engagement elements be included in the thread profile to be displaced, wherein, based on an engagement element between two displacement profiles a displacement-free space remains. In particular, a vote also possible in the way that over the entire Gleitweg a same or at least approximately the same sliding resistance is effective. specially can also be provided that on the Gleitankerkopf two pairs of each provided two mutually circumferentially engaging elements are whose pairs connecting lines of the engaging elements each other in Cut the projection vertically, and that the engaging elements of each one same pair to each other in phase and each different pairs to Achieving a play-free threaded engagement in phase with respect to the External thread are arranged. Thus, for example, four each by a quarter turn on the circumference and in pairs about half the thread pitch be present in the axial direction of the pipe anchor offset elements which can be adjusted with a thread gauge so that the engaging ends, For example, cone tips, each on opposite thread flanks issue. The sliding nut can thus, for example, to a maximum load in Gleitankerlängsrichtung in the range of 50 to 100 kN, preferably one maximum load of 70 kN, to be set over the gliding path remains about the same, so that when sliding no jerky compliances or shocks occur. The engagement element or its engagement end (eg. Cone tip) may preferably be hardened, so that when penetrating the External thread no wear occurs. It is further preferred that the External thread of the anchor rod throughout over its entire length extends, so that needed for the expected convergence of the mountains Gleitweg of the sliding anchor head by a correspondingly sufficient length the anchor rod is to achieve. For a long anchor rod, the glide path be limited by the fact that an end stop, for example by a On this screwed ball nut, is provided. The convergences of the mountains become well visible through the glide path (furrows). An excess Anchor overhang, which does not disappear in the mountain, can later be separated become. It is further preferred that the sliding anchor in addition to the aforementioned Anchor rod still a number of other anchor rods with corresponding and over the length of passing external thread comprises, so that all anchor rods by means of coupling nuts with matching internal thread are connectable. This brings the advantage that the sliding anchor in Shots that can be connected through the coupling nuts, even in confined spaces Space, in the mountains can be introduced. Finally, there is also the Possibility that at least the Gleitankerkopf assigned to the sliding movement Anchor rod made of duplex steel, preferably made of duplex steel with the properties explained in more detail below and more preferably made of duplex steel with the international material no. 1.4462, exists. according to the thereby high elastic and plastic deformation capacity are in the displacement of a thread rib section, the case formed End areas under continuous displacement resistance to the following Thread groove shifts into it, creating an over the glide path away surprisingly uniform sliding resistance is obtained.

The present invention further relates to a sliding anchor, in particular self-drilling slip injection anchor comprising at least one anchor foot bar section, in particular at least one first anchor rod, and at least an anchor head bar section, in particular at least one further Anchor rod, and at least one Gleitankerkopf which along the anchor rod section overcoming a sliding resistance in Gleitankerlängsrichtung is displaceable.

In the case of cavity protection, the problem is especially in the case of rocky mountains given that in yielding shoring in the longitudinal direction of the anchor running shifts in the ground to a high tensile load of Anchor. This is under otherwise the same conditions, the lower, depending further away, the actual anchoring route of the sliding anchor from Cavity edge is located. The anchoring section provides the longitudinal section of the anchor, in which, for example, injection with injection fluid (e.g. Cement milk) or sticking in the borehole. Because the tensile load the anchor rod under otherwise equal conditions, the lower, the farther removes the anchoring or Verpressstrecke distance from the cavity edge is the requirement of proof of the anchor in the area of Anchoring or Verpressstrecke thus often to relatively large and thus uneconomical anchor lengths. Based on this, the invention the object of a sliding anchor of the aforementioned type, as this is also to be taken from DE 3507089 A1, use technically develop advantageous, so that in particular in pressure mountains a high overload safety is achievable.

This object is according to the invention first and essentially thereby solved that the sliding anchor head to a certain sliding resistance on the Anchor rod rod section, in particular on the other anchor rod adapted is, wherein the sliding resistance limits the armature clamping force such that the resulting in the Ankerfußstangenabschnitt, especially in the first Anchor rod, maximum resulting tension is less or at most about is equal to the local material elastic limit. The hole deepest associated anchor foot bar section is the section of the sliding anchor, anchoring in the borehole. In the preferred according to the invention self-drilling slip injection anchor anchoring takes place thereby, that by an injection channel in the anchor longitudinal direction and its outlet openings in the region of the drill bit a Verpressfluid, as for example. Cement milk, starting from the wellbore deepest under preferably further rotation of the armature is pressed into the wellbore. The anchor head bar section is the longitudinal opposite, i. the borehole mouth associated anchor section. The anchor foot bar section and The anchor head rod section can basically either at one common, i. continuous anchor rod or, as in the present Invention preferred, provided on various anchor rods be. The latter can in turn either adjacent or under interposition Further anchor rods, for example, connected to each other by coupling elements be. By according to the invention with the predetermined sliding resistance between the sliding anchor head and the anchor head rod section in the anchor foot rod section tension limited to at most about elastic limit is achieved by biasing the sliding anchor there is no overload is possible and the least remaining plastic extensibility is available for recording shifts in the subsurface. This allows the length of the anchor even in unfavorable ground conditions limit, depending on total loads and sliding resistance or armature clamping force of a single armature a corresponding Number of anchors can be selected. At the elastic limit Depending on the material behavior, the anchor foot material may be around the so-called yield strength or act around the lower yield strength. Is preferred in that the material elastic limit of the Ankerfußstangenabschnittes two to five times, more preferably about 2.5 times that in the Ankerfußstangenabschnitt maximum resulting voltage is. This means that with preloaded anchor also additional shifts of the Underground at the Ankerfußstangenabschnitt initially only a small cause elastic strain, which advantageously also the risk of damage of the shear bond through the grout or cement stone is reduced. This overload protection is particularly important for a possible biasing of the sliding anchor by means of the sliding anchor head already shortly after one for anchoring the sliding anchor in the anchor hole used shear composite medium, for example on a cement or adhesive basis, has been introduced into the anchor hole. It is preferred that the resulting from the particular sliding resistance of the Gleitankerkopfes Shear stress between anchor rod section and shear composite medium less than the shear strength between anchor foot bar section and finally cured shear composite medium, in particular that these 20 to 80%, more particularly about 50%, of said shear strength is. This means that may only after a period of time from, for example, several hours of setting or hardening available standing full shear strength of the Scherverbundes by those from the selected Sliding resistance of the sliding anchor head resulting shear stresses is not fully exploited and thus biasing the sliding anchor even after a shorter waiting time is possible. Also, this is for the Case that the pressure mountain pushes strongly, a shear strength reserve against shearing off the possibly not yet hardened shear composite medium of provided to the exterior of the anchor foot bar section. Furthermore is preferred that at least the anchor rod in the region of Ankerfußstangenabschnittes is made of a material whose yield ratio (i.e. the ratio of yield point to ultimate load) in the range between 0.5 and 0.7, in particular about 0.6. It is possible, for example, an embodiment, in which an anchor rod provided at anchor foot only at a assumed anchor tensile stress of about 175 kN the 0.2% proof stress while the breaking load with an anchor force of approx. 300 kN and 13.5% elongation is still significantly higher. The sliding resistance of the Gleitankerkopfes along the anchor rod in the region of the anchor rod section can thereby preferably to a maximum load in the longitudinal direction be adapted from 70 kN. As a material for the Ankerfußstangenabschnitt as well as in particular for other anchor sections is in particular a heat-treated austenitic steel with a high plastic stretchability or austenitic-ferritic steel, in particular a so-called duplex steel with the international material no. 1.4462, to take into account. In Combined with the high plastic extensibility tensile stresses in the area of the anchoring line, the anchor steel on the Shifts of the subsurface are forced, with appropriate Choice of anchor length from the steel tension member with sufficient safety distance be recorded. The use of such materials offers compared with, for example, conventional fine grain steels the advantage that the required Anchor length thus shortened and securing the cavity more economical to shape is. The low yield ratio and the high ductility make such an anchor ideally suited to large displacement paths the depressing mountains, possibly even down to the decimeter range, to endure without breakage. The result is the adaptation of the sliding anchor head to a certain sliding resistance along the anchor head bar section an overload protection of the shear compound in the grouting section achieved by choosing a material that meets the high ductility of austinitic microstructure with the high bearing capacity of ferritic microstructures connects, can still be increased. The shear strength between anchor foot bar section and shear composite medium can be improved thereby, in that the anchor foot bar section has an external thread, in particular a rolled external thread, owns. With respect to the anchor head is advantageous if this also has an external thread and a Gleitankerkopf with at least one pin-like, to an engagement in the external thread adapted for screwing the Gleitankerkopfes on the anchor rod Engagement element is provided, wherein the intervention when exceeding a certain Sliding resistance to achieve a displaceable yielding is. Also the others, already leading to such a sliding anchor head described features can be realized individually or in combination be.

Also, an embodiment of the sliding anchor can offer advantages in which between a crimping section or anchor foot section and an anchor head section a free play section is provided, which is a substantially smooth one Having outer surface. In the free play track becomes aware of this Scherverbund avoided with the borehole wall, allowing a free longitudinal expansion the armature between the Verpressstrecke and the anchor head allows and from the anchor larger displacement paths of the pressure Mountains without overloading of the shear bond in the Verpressabschnitt can be compensated. An expedient development of the sliding anchor is also possible because of the anchor foot bar section, the anchor head bar section and in particular the free play section on separate Anchor rods are provided, which is a similar, over the length have continuous external thread and by means of coupling nuts with Matching internal thread can be connected. Suitable are, for example, round threads, Trapezoidal thread or the like, preferably on the rod outside rolled up. The thread ribs may have a groove at the apex, as described for example in DE 3400182 A1. A corresponding modular sliding anchor can be in shots connected by coupling nuts are used even in confined spaces. Next is preferred that in the free play section the anchor rod outer thread to the Achieving a smooth outer surface of a jacket, in particular is encased in a PVC hose. The PVC hose can do this first For example, expanded with compressed air, in corresponding lengths pushed onto the anchor rods and then shrunk by switching off the pressure whereupon the putting into the underground in shots he follows. In an expedient embodiment as Gleitinjektionsanker is further preferred that the anchor rods in the longitudinal direction continuously respectively a closed hollow cross-section with, for example, circular or polygonal Own form. By the continuous through the sliding anchor inner channel can from the drive side of a known injection means or Shear composite medium, such as cement slurry, through the slip anchor preferably to a drill bit attached to the anchor tip and through openings in it from the wellbore deepest in the annular gap around the Sliding anchors are pressed. Alternatively, in the context of the present Invention also anchor rods are used with a solid cross-section, the sliding anchor then by means of separately introduced into the well Adhesive can be anchored.

Fig. 1

in geschnittener Längsansicht den erfindungsgemäßen Gleitanker gemäß einer bevorzugten Ausführungsform, in das Gebirge eingebracht,

Fig. 2

eine gegenüber Fig. 1 vergrößerte, ausschnittsweise und teilweise aufgebrochene Ansicht des in Fig. 1 gezeigten Ankerkopfstangenabschnittes mit Gleitankerkopf Schnittrichtung II-II,

Fig. 2a

eine noch weitere Ausschnittsvergrößerung des Ausschnittes IIa in Fig. 2,

Fig. 3

eine teilweise geschnittene Ansicht des in Fig. 2 dargestellten Ausschnittes des Ankerkopfstangenabschnittes mit Gleitankerkopf, in dort bezeichneter Schnittrichtung III-III,

Fig. 3a

eine noch weitere Ausschnittsvergrößerung des Ausschnittes IIIa in Fig. 3,

Fig. 4

eine teilweise geschnittene Seitenansicht der Gleitankerkopfhülse in einer bevorzugten Ausführungsform,

Fig. 5

einen Querschnitt der Gleitankerkopfhülse nach Fig. 4 entlang Schnittlinie V-V und

Fig. 6a-6d

eine schematische Wiedergabe des spielfreien Gewindeeingriffs.

The invention will be explained in more detail below with reference to the accompanying drawings, in which a possible embodiment is shown without limiting the scope. It shows:

Fig. 1

in a longitudinal sectional view of the sliding anchor according to the invention according to a preferred embodiment, introduced into the mountains,

Fig. 2

1 compared to FIG. 1 enlarged, partial and partially broken away view of the anchor head rod section shown in Figure 1 with Gleitankerkopf cutting direction II-II,

Fig. 2a

a further detail enlargement of the detail IIa in Fig. 2,

Fig. 3

a partially sectioned view of the section shown in Figure 2 of the anchor head rod portion with Gleitankerkopf, in there designated cutting direction III-III,

Fig. 3a

a further detail enlargement of the detail IIIa in Fig. 3,

Fig. 4

a partially sectioned side view of the Gleitankerkopfhülse in a preferred embodiment,

Fig. 5

a cross-section of the Gleitankerkopfhülse of FIG. 4 along section line VV and

Fig. 6a-6d

a schematic representation of the play-free threaded engagement.

Fig. 1 shows in a sectional longitudinal view of a preferred embodiment the sliding anchor according to the invention, which in a surrounded by mountains 2 Drill hole 3 is already anchored. The example chosen is in the sliding anchor 1 to a self-drilling Gleitinjektionsanker, the as a system anchor in several shots of one to be secured, not closer shown cavity starting through a concrete wall 4 through the mountains 2 was introduced. The sliding anchor 1 has, the well deepest 5, a drill bit 6, which initially with an internal thread on a cut anchor rod 7 shown with matching external thread is screwed on. The anchor rod 7 has a center in the longitudinal direction through cavity 8, which in the drill bit 6 in conjunction with another cavity is located, leading to several at the periphery of the drill bit 6 distributed, not shown outlet openings branched out. At the aforementioned anchor rod 7 close in armature longitudinal direction yet further, in the selected example geometrically corresponding anchor rods. 7 at. In the longitudinal direction adjacent anchor rods 7 are each through a Coupling nut 10 connected to the external thread of the anchor rods 7 matching internal thread screwed on the respective ends are. The overall length of the sliding anchor 1 achieved in this way is dimensioned so that this with a free end 11 of a terminating anchor rod 7 on the concrete wall 4 in the cavity to be secured, for example. Tunnel, survives. The free End 11 is broken in Fig. 1 to indicate that the free end can also have a different length as needed. The anchor rods 7, with the drill bit 6 in a conventional manner as a self-drilling injection anchor are to be introduced into the mountains 2, thus forming a central continuous Feed channel, through which from the free end 11 and the drive side starting a shear composite medium 12 over the wellbore 5 deepest in the borehole 3 can be pressed. The pressing of the shear composite medium 12 can be done with continuous armature rotation, thereby anchoring a shear bond between Gleitanker, in particular the external thread of the Anchor rods, and shear composite medium on the one hand and Scherverbundmedium and mountains on the other hand. In the so formed in the hole 3 Pressing body 13 can in the Scherverbundmedium, such as. Cement milk, also solid, such as cuttings or the like, embedded be. In order to support an approximately central alignment in the borehole 3, can be a suitable number of on the external thread of the anchor rods as needed 7 screw-on spacers 14 with fluid passage openings be provided. The achievable for the shear composite medium 12 annulus in the borehole 3 is in anchor longitudinal direction in the example chosen limited by a per se also known well closure 15, which at the height of the mountains 2 facing edge region of the concrete wall 4 is arranged. To brace the concrete wall 4 against the mountains 2 can, is on the anchor rod 7 in the region of the free end 11 a Gleitankerkopf Screwed 16 according to the present invention, so that this against a supported on the concrete wall 4 dome plate 17 presses. Of the Gleitankerkopf 16 also has the property that he under overcoming a certain preset sliding resistance of his on the Anchor rod 7 screwed position starting in Gleitankerlängsrichtung L is displaceable, with reference to the underlying mode of action below will be discussed separately. A longitudinal displacement of the sliding anchor head 16 by pushing the mountains 2 is only by an end stop 18 limited in the example as a screwed onto the anchor rod 7 Ball nut is formed. In the example chosen are arranged in a central longitudinal section of the sliding anchor 1 anchor rods 7 between the coupling nuts 10 with length sections PVC hose 19 sheathed, so due to the smooth outer surface no shear bond with the grout 13 is formed and thus a free Play of the anchor longitudinally opposite mountains 2 and concrete wall 4 is possible. The corresponding length portion of the sliding anchor 1 is therefore in the context of the present invention referred to as free play section S. At this joins up to the borehole deepest 5 an anchor foot rod section F, across which the shear bond between the sliding anchor 1 through the Pressing body 13 through to Mountains 2 is formed. To the free play section S closes to the cavity to be secured even the so-called. Anchor rod section K to which the Gleitankerkopf 16 is assigned. With the in Fig. 1 only symbolic risers is indicated that the Anchor rods 7 may have different lengths, or that in the various Sections basically a different number of anchor rods 7 is possible. Anchor footstep section, free play section and Anchor rod section can, as in the example chosen, from a each integer number of anchor rod 7 consist. On the other hand are but also overlaps and possibly even across all sections continuous anchor rod conceivable. For ease of use is regarding individual anchor rods 7 a length of, for example. 2 meters appropriate. By assembling by means of coupling nuts 10 can then For example. Ankerfußstangenabschnitt as anchoring a length of For example, 2 meters, 4 meters, preferably 6 meters, etc. reach. According to the invention is in the sliding anchor 1 of the sliding anchor head 16 to achieve a certain sliding resistance on the anchor head rod section K adapted which limits the armature tensioning force such that it results in the armature footstep section F resulting voltage less than or at most about equal to the material elastic limit of the Ankerfußstangenabschnittes F is. In In the example shown in Fig. 1, the sliding anchor head 16 is so on the anchor head rod portion K forming anchor rod 7 tuned that he off reaching or exceeding a compressive force of the concrete wall 4 against the Dome plate 17 or sliding sleeve of 70 kN while maintaining the sliding resistance on the anchor rod 7 in the direction of the end stop 18 longitudinally displaceable is. The anchor rod (s) of the Ankerfußstangenabschnittes F, the made of duplex steel material no. 1.4462, experienced at one of the anchor rod 7 of the anchor rod section K corresponding cross-section even with an anchor force of about 175 kN, i. about 2.5 times the Selective sliding resistance, an elastic strain of less than 1%, the below the material elastic limit of the duplex steel used. When biasing the sliding anchor 1 by means Gleitankerkopf 16 is the Anchor force limited by the specific sliding resistance to a maximum of 70 kN. The strain resulting in the anchor foot bar section F becomes limited by this overload protection to such a low level that the danger Damage to the shear bond between anchor rod 7 and Pressing body 13 is largely reduced. After tightening the Sliding anchor 1 performs a sliding of the mountain 2 against the concrete wall 4 first in addition, that due to higher tie-pull load and exceeding the sliding resistance the sliding anchor head 16 in still maintained sliding resistance towards the end stop 18 slides until the sliding action by support is terminated. With further pushing of the mountains the anchor force increases. In the above value example stands as Breakage protection initially up to at least 2.5 times the Ankervorspannkraft an elastic stretching behavior of the anchor rods made of duplex steel to disposal. Due to the low yield ratio of duplex steel can be an even more increasing in the chosen example Stress due to a subsequent plastic deformation still up to a breaking load of about 4 times that of the sliding anchor head 16 chosen sliding resistance are endured. In the longitudinal direction under Become in Slip anchor 1 and Mountains 2 different strains compensated in the free play section S by the longitudinal displacement. Depending on Demand may also be the anchor rods 7 in the free play section S. and / or in the anchor rod section K of an austinitic-ferrite Material, such as duplex steel exist.

FIG. 2 shows the sliding anchor head 16 of the sliding anchor 1 shown in FIG a contrast enlarged sectional view taken along section line II-II, wherein the dome plate 17 is not shown. Furthermore, FIG. 3 shows a to Fig. 2 vertical sectional view taken along section line III-III in Fig. 2. The Sliding anchor head 16 has a sleeve 20 with through hole 21. These has a substantially smooth inner wall and is in diameter to Enabling a displacement in the longitudinal direction L slightly larger as the external thread 22 of the anchor rod 7 dimensioned. The sleeve 20 has in their wall on the circumference offset by a quarter turn each other lying threaded holes 23, in which in each case an engagement element 24, in the example chosen a hardened stud, screwed in radially is. The engagement elements 24 have, facing the anchor rod 7, depending on a cone tip 25 with flattened end, which is when screwing in the threaded holes 23 in engagement with the external thread 22 of the anchor rod 7 bring. In accordance with gradual adjustability is in the Figures 2 and 3 chosen an engagement depth, which is approximately equal to the thread depth of the external thread 7, so that the flattened end of the conical tips 25th the thread base 26 of the external thread 7 just not or hardly noticeable touched. Here is the set depth of engagement and at the same time holder of Engagement elements 24 secured by a respective lock nut 27. How special From FIGS. 2a and 3a, the conical tips 25 are supported in FIG Lengthwise L only on one side of the external thread 22 from, wherein along the lines of intersection VIa-VIa or VId-VId running through the support in the longitudinal direction L of the thread rib distance A greater than the Erstrekkung E of the engagement member 24 is. In Figures 2 and 3, the position is correct the sleeve 20 in the longitudinal direction L on the anchor rod 7 match, the two shown in FIG. 2, opposing engagement elements 24 in Viewing direction both on the right side and the two further shown in FIG. 3, opposing engagement elements 24 in the direction of both left side, i. the aforementioned opposite, on the external thread 22 abut. This means that in the interaction of the four engagement elements a total play-free engagement of the sliding anchor head 16 in the external thread 22 is realized. In that regard, the two are, for example, shown in Fig. 2 Engagement elements 24 in the sense of the present invention in phase with each other arranged with respect to the external thread 22. The same applies to the in Fig. 3 engagement elements 24, while in the ratio of the engagement elements both figures a phase-unequal position is provided to each other. This is, as well as the figures 4 and 5 show, on the sleeve 20 by a in Longitudinal L selected offset of the threaded holes 23 reaches, which suitable for the pitch of the external thread 22, the relative position of Tapped holes 23 on the circumference of the sleeve 20 and the thread rib distance is tuned. By rejuvenating to its free end Engagement end of the engagement elements 24 is the possibility of the engagement depth to be set so that in the longitudinal direction L a virtually straight clearance setting is obtained, which at the same time a screwing the Gleitankerkopfes 16th allowed on the anchor rod 7. Instead of the tapered conical tip 25 in the profile For example, a hemispherical engagement end could also be provided for this purpose. The profile of the engagement end can in particular also be designed so that the previously described backlash-free and suitable for screwing engagement automatically results when the engagement elements until just a slight Touching the thread root 26, i. up to a just noticeable increase be screwed in the torque. The described sliding anchor head 16 can be pre-assembled on the anchor rod 7 on the one hand in the manner that the sleeve 20 is pushed freely in the longitudinal direction L in a desired position and the engagement elements 24 are only screwed in there. on the other hand can the engagement elements 24 also preassembled on the sleeve 20 with this can be screwed onto the anchor rod 7. In the described Gleitankerkopf 16, the female thread is thus hinted by the four hardened, radially screwed studs generated in each case a quarter turn on the circumference and in pairs about half the thread pitch of the drilling anchor are arranged offset in the axial direction. The stud bolts can be adjusted in particular with a thread gauge, that the conical tips each at opposite thread flanks of the Threaded rib 28 or abut at the fillets in the foot area. The respective system goes along in the longitudinal direction L with a positive connection, so in engagement elements 24 used a longitudinal displacement of the Gleitankerkopfes 16 on the anchor rod 7 without a simultaneous rotation is initially prevented. The pitch of the threaded rib 28 is selected that a self-locking threaded engagement is formed, i. one on the Gleitankerkopf 16 in the longitudinal direction L acting axial force not automatically too a rotation leads. In the embodiment shown, the positive connection remains in both possible load directions until reaching a Axial force of about 70 kN obtained. When exceeding this predetermined Slip resistance plows the hardened conical tips 25 in the longitudinal direction over the anchor rod 7 and pull axial grooves 29 in the external thread 22nd in (see Figures 2 and 3), with the hardened conical tips 25 passing through the deformation path are not subject to wear. The backlash-free intervention brings in connection with the radii transitions 30 of the threaded rib 28 and the choice of an anchor rod 7 made of duplex steel at the same time the advantage that at a continued load of the sliding anchor head 16 no jerky movements can arise. This amounts to in the specific example chosen the outer diameter D of the anchor rod 7 about 29 mm, the thread base diameter d about 24 mm and the radius of the radius transitions 30 about 6 mm. The engagement elements are threaded pins with a cone point according to DIN 914-M12 x 40 provided. The initial state, i. for example, during toughening the sliding anchor formed by the four engagement elements 24 backlash threaded engagement is further described schematically in Figures 6a to 6d. Figures 6a and 6d are going to the corresponding cutting guides in Figures 2a and 3a back.

All disclosed features are essential to the invention. In the revelation the application is hereby also the disclosure of the associated / attached priority documents (copy of the prior notification) in full included, also for the purpose, features of these documents in Claims of the present application to include.

Claims (24)

Sliding anchors, in particular self-drilling Gleitinjektionsanker, comprising at least one externally threaded anchor rod and at least one Gleitankerkopf which is displaceable along the anchor rod overcoming a sliding resistance, characterized in that the Gleitankerkopf (16) one or more pin-like, to an engagement in the external thread (22) for screwing the Gleitankerkopfes (16) on the anchor rod (7) adapted engagement elements (24), wherein the engagement when exceeding a certain sliding resistance to achieve the displaceability is yielding. Sliding anchor according to claim 1 or in particular according thereto, characterized in that at least one engagement element (24) when exceeding the specific sliding resistance of the sliding anchor head (16) with its engagement profile to achieve the compliant engagement causes a displacement of the external thread rib (28). Sliding anchor according to one or more of the preceding claims or in particular according thereto, characterized in that the engagement depth of the engagement element (24) in the external thread (22) is adjustable, in particular continuously adjustable, is. Sliding anchor according to one or more of the preceding claims or in particular according thereto, characterized in that the engagement element (24) in the sliding anchor head (16) passes through a bore facing the anchor rod (7) and is longitudinally adjustable therein by means of adjusting threads. Sliding anchor according to one or more of the preceding claims or in particular according thereto, characterized in that the engagement depth of the engagement element (24) in the external thread (22) is approximately equal to or slightly smaller than the thread depth of the external thread (22). Sliding anchor according to one or more of the preceding claims or in particular according thereto, characterized in that a plurality of in the circumferential direction of the sliding anchor head (16) in particular evenly distributed engagement elements (24) is provided. Sliding anchor according to one or more of the preceding claims or in particular according thereto, characterized in that in Gleitankerlängsrichtung (L) the thread rib spacing (A) of the external thread (22) is greater than the extension (E) of the engagement element (24), in particular their approximately two- is up to triple. Sliding anchor according to one or more of the preceding claims or in particular according thereto, characterized in that the sliding anchor head (16) has at least two engagement elements (24) which are held with respect to the external thread (22) of the anchor rod (7) in mutually unequal phase position, so that in Gleitankerlängsrichtung (L) a total backlash engagement of the sliding anchor head (16) in the external thread (22) of the anchor rod (7) results. Sliding anchor according to one or more of the preceding claims or in particular according thereto, characterized in that on the sliding anchor head (16) two pairs of two circumferentially opposed engaging elements (24) are provided whose pairs connecting lines of the engagement elements (24) perpendicular to each other in projection cutting, and that the engagement elements (24) of a respective same pair are arranged in phase with each other and different pairs to achieve a play-free threaded engagement in phase with respect to the external thread (22). Sliding anchor according to one or more of the preceding claims or in particular according thereto, characterized in that the external thread (22) of the anchor rod (7) extends continuously over its entire length. Sliding anchor according to one or more of the preceding claims or in particular according thereto, characterized in that the sliding anchor (16) comprises a number of further anchor rods (7) with similar and over the respective length passing through external thread (22). Sliding anchor according to one or more of the preceding claims or in particular according thereto, characterized in that the thread profile of the external thread (22) and the thread engagement of the sliding anchor head (16) formed by a number of engagement elements (24) are tuned such that a continuous along the Gleitweges Sliding resistance, in particular a substantially constant sliding resistance, is effective. Sliding anchor according to one or more of the preceding claims or in particular according thereto, characterized in that the threaded rib of the external thread (22) has a substantially trapezoidal cross-section, wherein the lateral trapezoidal flanks rounded into the thread roots. Sliding anchor according to one or more of the preceding claims or in particular according thereto, characterized in that at least the anchor rod (7) assigned to the sliding anchor head (16) for sliding movement of duplex steel, in particular of duplex steel of international material no. 1.4462, is formed. Sliding anchors, in particular self-drilling Gleitinjektionsanker, comprising at least one Anchorfußstangenabschnitt, in particular at least a first anchor rod, and at least one anchor head rod portion, in particular at least one further anchor rod, and at least one Gleitankerkopf which along the Anchor rod portion overcoming a sliding resistance in Gleitankerlängsrichtung is displaced, characterized in that the sliding anchor head (16) is adapted to a certain sliding resistance on the anchor head rod section (K), in particular on the further anchor rod (7), wherein the sliding resistance limits the armature clamping force such that it results in the anchor foot rod section (F), in particular in the first anchor rod (7), the maximum resulting stress is less than or at most approximately equal to the local material elastic limit. Sliding anchor according to claim 15 or in particular according thereto, characterized in that the material elastic limit of the Ankerfußstangenabschnittes (F) is two to five times, in particular about 2.5 times, in the Ankerfußstangenabschnitt (F) resulting maximum stress. Sliding anchor according to one or both of claims 15 and 16 or in particular according thereto, characterized in that the sliding anchor (16) can be anchored to the anchor foot rod section (F) by means of a shear composite medium (12), such as cement or adhesive, in the anchor bore (3) and the maximum shearing stress between anchor rod section (F) and shear composite medium resulting from the sliding resistance of the sliding anchor head (16) is less than the shear strength between anchor rod section (F) and cured shear composite medium, and more preferably 20 to 80 percent, more preferably about 50 percent, of said shear strength. Sliding anchor according to one or more of claims 15 and 17 or in particular according thereto, characterized in that at least the anchor foot rod section (F) consists of a material whose yield ratio is between 0.5 and 0.7 and in particular about 0.6. Sliding anchor according to one or more of claims 15 to 18 or in particular according thereto, characterized in that at least the anchor foot rod section (F) made of a material with austinitic-ferritic microstructure and in particular of duplex steel, more particularly of duplex steel with the international material no. 1.4462, exists. Sliding anchor according to one or more of claims 15 to 19 or in particular according thereto, characterized in that the anchor head rod section (F) has an external thread (22) and at least one slide anchor head (16) according to one or more of claims 1 to 14 is provided. Sliding anchor according to one or more of claims 15 to 20 or in particular according thereto, characterized in that the sliding anchor (1) between the Ankerfußstangenabschnitt (F) and the Ankerkopfstangenabschnitt (K) has a free play section (S) with a substantially smooth outer surface. Sliding anchor according to one or more of claims 15 to 21 or in particular according thereto, characterized in that the anchor foot rod section (F) and / or the anchor head rod section (K) and / or the free play section (S) is formed by at least one separate anchor rod (7) , wherein the anchor rods have a similar, over the length of continuous external thread and means of Kupplungsmut tern (10) with matching internal thread can be connected. Sliding anchor according to one or more of claims 15 to 22 or in particular according thereto, characterized in that in the free play section (S) the anchor rod outer thread (22) to achieve a smooth outer surface of an envelope, in particular of a PVC tube (19), is sheathed , Sliding anchor according to one or more of the preceding claims or in particular according thereto, characterized in that the anchor rods (7) have a continuous hollow cross-section in the longitudinal direction and / or in that the threaded rib of the external thread has a groove in its apex region.

Images