DE2749068A1 - Mine anchorage rod embedded in hardening resin - has flexible externally roughened inner plastics sleeve around glass fibre rods - Google Patents

Abstract

The anchoring rod used in mining operations has a head portion (1) made of steel tube, and the portion (2) which protrudes from the hole (6) is threaded externally for a nut to secure a clamping plate (4) on the outside, as in the main patent. At this end is a sealing sleeve (10), and at the inner end protrude glass fibre reinforced plastics rods (8). A plastics inner sliding tube (16) projecting from the head portion encloses most of the length of these rods, and having a plastics plug (17) in its innermost end, also enclosing the rods. At the point where the head portion passes through the sealing sleeve, there is a feed channel for the plastics resin setting substance which is injected. The plastics tube (16) is flexible and has a roughened exterior.

Description

Mountain anchor

Addition to P 26 24 559.0 The invention relates to a rock anchor according to the preamble of claim 1 according to the main application P 26 24 559.0.

When fortifying and securing mountain formations with poor Rock quality classes it is desirable and necessary for a permanent final expansion to set prestressable rock anchors. It is supposed to mean the; Rock pressure or movements the required adhesive and supporting effect is counteracted in a controlled manner at an early stage and thus the rapid stabilization of the cavity and securing of the mountains can be achieved in the long run. It is true that the one described in the main application Rock anchors are prestressed to a limited extent during the period of time between the hardening of the synthetic resin in the end of the borehole on the one hand and the mouth of the borehole on the other hand passes. However, the full leeway the prestressing of the anchor's reinforcement elements can be exploited. Also is the pre-tensioning can no longer be controlled after curing.

The invention is therefore based on the object of a rock anchor of the type mentioned to create the one corresponding to the material properties Has free play area in which it can be preloaded to any desired force values is.

This task is solved by a rock anchor with the characteristics of claim 1.

The result is a mountain anchor that protects against corrosion and aggressive mountain waters and acids is resistant and insensitive to stray currents, at which Set no washout when a water flow in the borehole takes place and one complete hardening of the anchor is also achieved under water, whereby the hardening time is very short and the full load capacity is quickly reached. An outflow from the Borehole is opposed by the type of filling and the waterproofing used not possible with the usual fillings. The new anchor connects extremely well well with the surrounding mountains penetrates into its unevenness and has a large elastic extensibility. Its adhesive and supporting effect is therefore over the entire length effective. Its metal anchor head can be removed. so that the Prestressed anchor can also be used when a later extension of the Stollen or the use of a milling machine is planned, but above all as a final expansion. With the new pre-tensionable rock anchor, the entire large area is the fully elastic elasticity of the synthetic resins with the glass fiber reinforced reinforcement elements exploitable in a precisely controlled manner for the bias. This is the case with epoxy resins existing tendency to creep for the prestressing properties and Strength properties of the anchor advantageous.

They transfer the rock pressures elastically to the high-quality glass fiber, which give the anchor its high level of effectiveness for stabilizing the mountains.

The bond strength of the rock anchor to the resin and the reinforcement is due to crushing or other unevenness of the surface of the anchor head reinforced and is further enlarged in the embodiment according to claim 3. In In the same way, the synthetic resin goes with the surrounding mountains or

a particularly intimate contact with the borehole wall. The elastic The bedding of the reinforcement elements in synthetic resin proves to be an intermediate link to the rock more deformable and therefore much more resilient than, for example the cement mortar between a steel anchor and the mountains.

In the embodiment according to claims 4 and 5, the length is of the reinforcement elements protruding beyond the free space around a quarter of the Total length of the anchor.

These length ratios have proven to be particularly advantageous.

When using fiberglass rods as reinforcement elements, you can with the embodiment according to claim 6 a particularly good adhesion of the reinforcement elements reach both in the anchor head and in the clamping space. Especially between these Points are preferably the pretensioning of the rock anchor (claim 7).

In the embodiments according to claims 8 and 9 it is ensured that both air and optionally water from the borehole during injection of the liquid synthetic resin through the ventilation pipe or the ventilation channel in the Anchor head can escape. This results in a complete filling of the Clamping space in which the Periphery of the entire borehole is filled with and sealed against the ingress of water.

The embodiment according to claim 10 is particularly useful if the anchor head can be removed from the borehole after prestressing target. Depending on how deep the anchor head is to be pushed into the borehole, the filling channels can be guided or run along the anchor head to a greater or lesser extent be milled (claim 11). Appropriately, the filling channels as well as the Ventilation channel incorporated into the outside of the anchor head (claim 12), however, these grooves would also be incorporated on the inside of the sealing ring conceivable. In order to optimally adapt the sealing ring to the borehole wall and a To ensure a good seal, the sealing ring is constructed according to claim 13.

By arranging a filling pipe and a ventilation pipe (claims 14 and 15) is the complete and perfect filling of the free space ensured. As with the filling of the clamping space through the filling channel (s) most expedient If a cranked hypodermic needle is used, it is also used for filling of the free play area with the help of the filling pipe or a filling channel Injection needle or filling probe.

In a particularly advantageous embodiment of a rock anchor (Claim 16) the free play tube is pulled over the anchor head to the mouth of the borehole, A filling pipe leads between the borehole wall and the outer wall of the free play pipe from the Borehole mouth to the clamping space and the anchor head has a groove or filling channel, which leads from the mouth of the borehole to the clearance space, and a clearance space vent pipe occurs laterally at the mouth of the borehole, advantageously below the thread of the anchor head the end.

The method of setting the new rock anchor is extraordinary simple. In particular, this rock anchor can also be set upside down without that special support devices would be required, since the elastic Seal, advantageously a conical lamellar seal, holds in the borehole. the Reinforcement elements (fiberglass tube and fiberglass rods) and, if necessary, filler and vent pipe for the clearance space are in the anchor head with epoxy resin The reinforcement elements are also cast at the end of the free play tube Epoxy resin sealed by potting. When the head of the mountain anchor after setting and prestressing of the anchor is to be removed, it is advisable to remove the reinforcement elements to be fixed by potting only in an outer end area of the anchor head. The The anchor head can then be easily removed by removing the reinforcement elements Saw off the potted end and remove the actual anchor head from the ends of the reinforcement elements withdraws. The fastening of the reinforcement elements in the anchor head as well as in the Free play tube can be done in this way before the anchor is set a prefabricated raw material for setting a mountain anchor available. The prestressing of the reinforcement elements can then either by separate devices, but also by anchor plate and tension nut (Claim 18). The mode of operation according to claim 19 provides a possibility of biasing even if the anchor head is subsequently removed from the borehole.

The new rock anchor is extremely powerful in terms of its performance on tunnel static and rock mechanical aspects and is particularly suitable for rock construction and tunneling. Its load capacity has been tested and proven in the range of 8 Mp up to 50 Mp, with lengths also tested from 4 to 8 m however, much further up to 100 Mp.

If necessary, lengths of up to 20 m and more are provided and controllable by adjusting the reaction rate of the filler resins. the The bias voltage that can be generated has been tested in a range of 10 to 15 Mp, but can can be increased considerably by reinforcement. As a synthetic resin to be filled, it is advantageous Epoxy resin used, the hardening time of which is 8 to 45 minutes, within which the epoxy resin reaches its full strength. This short hardening time enables the anchoring work to be carried out quickly and efficiently, and thus a rapid effect of anchor forces on rock movement. The epoxy resin is insoluble against mountain water and acids and is waterproof.

In terms of manufacturing costs, the new anchor with anchors must be the same Performance, including all expenses for increased corrosion protection known anchor. In addition to the technical advantages also price advantages of the new anchor.

The invention is illustrated below with the aid of exemplary embodiments Referring to the drawings explained in more detail. These show in: FIG. 1 an axial section by a rock bolt placed in the borehole prior to backfilling with the synthetic resin; FIG. 2 shows a cross section through the rock anchor in plane II-II of FIG. 1; FIG. 3 shows a cross section corresponding to FIG. 2 through another embodiment with increased reinforcement of the rock anchor for greater prestressing and tensile force than in the anchor shown in Figure 2; FIG. 4 one of FIG. 2 corresponding Cross-section through another embodiment of the GebirgsankeKs for even larger ones Bias and tensile force than in the anchor of Figure 3; Figure 5 is a side view of the sealing ring; FIG. 6 shows an axial section through one placed in the borehole Mountain anchor in which the free play tube 16 over the anchor head 1 to the mouth of the borehole is preferred; FIG. 7 shows a cross section through the rock anchor in plane I-I the Figure 6 and Figure 8 shows a cross-section corresponding to Figure 7 through a another embodiment with increased reinforcement of the rock anchor.

The anchor of Figures 1 and 2 is for a tensile force of 30 t and one Designed preload of 15 t. It has a tubular anchor head 1 made of steel on, on whose threaded end 2 protruding from the borehole 6, an anchor plate 4 can be pushed which can be tightened against the mountain 5 with a tension nut 3. Of the Anchor head 1 has to increase the static friction with respect to the surrounding area and filling synthetic resin pinches 22 or annular groove-shaped and annular web-shaped Deformations of its wall.

In the end of the anchor head 1 protruding into the borehole 6 there is a free play tube 16 pushed. It consists of synthetic resin and is flexible or roughened on the surface or corrugated to increase its static friction with respect to the synthetic resin to be filled enlarge. The synthetic resin of the free play tube 16 can for example be polyurethane be. The end of the borehole facing the end of the free play tube 16 is through a sealed plug 17 made of epoxy resin, through which reinforcement elements 7, 8 made of glass fiber reinforced synthetic resin, here epoxy resin, are passed through.

These reinforcement elements are glass fiber reinforced Plastic ventilation pipe 7, as well as one or two or more GRP rods 8 (glass fiber reinforced Plastic rods). These reinforcement elements 7, 8 extend over the entire Length of the rock anchor, i.e. from the threaded end 2 of the anchor head 1 in which it are potted with epoxy resin, up to the end of the drill hole through the anchor head 1 or the Free play tube 16, from which they then protrude a little further to the end of the borehole. The reinforcement elements 7, 8 are sealed by the synthetic resin plug 17 passed through, and also the plug connection of the free play tube 16 in the anchor head 1 is sealed, if necessary with the help of adhesive tapes and otherwise. To this Wise is that of the mountain anchor occupied volume of the borehole 6 divided into an outer one, i.e. surrounding the anchor head 1 and the free play tube 16 Clamping space 15, and into an inner one, i.e. within the anchor head 1 and the free play tube 16 located free space 18, which is limited by the synthetic resin plug 17 and 28 can be.

The clamping space 15 is through at least one in the area of the borehole mouth Ring-shaped seals, preferably a conical one, placed around the anchor head 1 Cuff 10, which has sealing lips resting against the wall of the borehole 6, sealed.

To fill the clamping space 15 with liquid, cold-curing synthetic resin, for example epoxy resin, is one in the outside of the anchor head 1 along about a surface line incorporated filling channel 14 is provided, which is under the sealing sleeve 10 is passed. It is via an injection needle 20, which is cranked, loaded with the synthetic resin. To ensure a flawless and complete Filling of the clamping space 15, ventilation slots 12 are provided in the ventilation pipe 7, as well as one or more ventilation channels 19 on the outside of the anchor head 1, which are designed and arranged analogously to the filling chute or chutes 14.

A particularly advantageous embodiment is shown in FIGS 8 shown. In this embodiment, the free play tube 16 is over the anchor head 1 pulled forward to the mouth of the borehole, between the borehole wall and the outer wall of the free play tube A filling pipe 25 leads from the mouth of the borehole to the clamping space 15 and has the anchor head a groove or filler channel 26 which leads from the mouth of the borehole to the clearance space 18, and a clearance vent pipe 27 occurs at the borehole mouth, advantageously below of the threaded end of the anchor head, to the side. In this embodiment the clamping space 15 between the borehole wall and the rock anchor through a filler pipe 25 through the Filling probe 24 filled with epoxy resin. The filler pipe 25 lies between the borehole wall and the outer wall of the free play pipe.

It leads from the mouth of the borehole through the sealing rings 10 into the borehole. The loading of the free play space is advantageous in this embodiment by a groove or filler channel 26 in the anchor head, which is advantageously below the thread end of the anchor head begins at the mouth of the borehole and with the help of a cranked filling probe 23 is charged with epoxy resin. The free space is vented at this embodiment by a vent pipe 27, which at the borehole mouth between Threaded head and free play tube emerges.

To facilitate the filling of the free space 18 inside of Anchor head 1 and free play tube 16 are a shorter filling tube 9 and a groove 26 as well a longer vent pipe 13 or 27, which from the threaded end of the anchor head 1 or from the mouth of the borehole to approximately the synthetic resin plug closing the free play tube 16 17 is enough, arranged in the anchor head 1 or the free play tube 16. The filling of the free play space 18 takes place accordingly by means of a filling probe 21 or 23 through the filling pipe 9 or the groove 26.

The complete filling of the clamping space 15 is visible on the Leakage of liquid synthetic resin from the ventilation pipe 7 and the ventilation channel 19; analogously, the complete filling of the free space 18 is indicated by the escape of liquid synthetic resin from the ventilation pipe 13 or 27.

To improve the static friction of the rod-shaped, glass fiber reinforced Synthetic resin reinforcement elements 8 are these fiberglass rods with splices at the end 11 provided. By the same token, the fiberglass tube and the fiberglass rods are 7 and 8 by a special manufacturing process along their entire surface aufaeauht. ; In the embodiment of FIG. 3, instead of two Glass fiber rods 8 as in Figures 1 and 2, four glass fiber rods 8 are provided. This Rock anchor is designed for a tensile force of 50 t and a preload of 20 t.

An even more resilient embodiment of the rock anchor is shown Figure 4, in which ten fiberglass rods 8 are provided. This embodiment of the rock anchor is designed for a tensile force of 100 t and a preload from 30 t.

Otherwise, the same reference symbols denote the same in all figures Parts. The free play space 18 is in the cross-sectional views (Figures 2 to 4) as already filled by the synthetic resin and therefore shown hatched.

The new rock anchor is set as follows.

The anchor head 1 is made with the cast reinforcement elements 7 + 8 and the attached free play tube 16, at the end of which the reinforcements are also back are sealed by potting, inserted into the borehole 6. The connection points of the Frelspielrohres 16 are sealed with adhesive tapes and other things. The reinforcement rods then about a quarter of the total length of the rock anchor protrudes over the free play tube out into the filling space or clamping space 15 of the borehole 6. With the help of the cranked Filling probe 20 or 24 is now the clamping space 15 through the under the sealing ring 10 through filling channel 14 or the filling pipe 25 is filled. Dac liquid and cold Filled synthetic resin rises first along the anchor head 1 and then the free play tube 16 to the Space at the end of the borehole 6. Air and possibly Water can flow from the borehole once through the vent pipe during backfilling 7 and also escape through the ventilation channel 19 in the anchor head 1.

After this synthetic resin filling has hardened, the reinforcement 'rods 7, 8 pretensioned in the free play space 18 to the desired pretensioning force and the pretensioning controlled. After this pretensioning and stabilization of the mountain forces, the Free space 18 with the help of the injection needle 21 or 23 through the filling tube 9 or the groove or filler channel 26 with the same cold epoxy through the anchor head 1 or filled from the mouth of the borehole. After the resin has hardened in the clearance space 18 the rock anchor is under tension and can be fixed by means of anchor plate 4 and tension nut 3 must be screwed tightly.

If intended, remove the anchor head from the wellbore after prestressing to remove, then the same is only inserted so far into the borehole that he after prestressing the anchor, it is flush with the mouth of the borehole. Accordingly are the filling and ventilation channel and the sealing ring on the mouth of the borehole to be attached facing end of the anchor head.

The pre-tensioning of the reinforcement must in this case by means of an over the anchor head pushed pressure tube, which is placed on the anchor plate placed against the mountains acts, take place by means of the clamping nut over the thread of the anchor head.

After pre-tensioning and filling as well as hardening of the free space any further screw connection can be omitted and the anchor head from the reinforcement rods separated and thus removed.

The prestressed anchor is therefore fully corrosion-proof, since it does not have any Contains iron parts and is due to the high adhesive and supporting effect of the hardened Epoxy resin with its glass fiber reinforcement as the ideal final construction of a mountain protection system effective in its entire length against mountain movements in the long term.

L e r s e i t e

Claims (19)

Patent claims 1. Rock anchor with a possibly after Put the anchor up to a removable tubular metal anchor head defined depth back into the borehole [protrudes, at his from the borehole mouth protruding end has an external thread and a tension nut for screwing on an anchor plate and in the region of the borehole mouth of at least one sealing the borehole Sealing ring is surrounded, with at least one arranged in the anchor head, in the Borehole end protruding rod or tubular reinforcement element made of glass fiber reinforced Plastic, according to patent application P 26 24 559.0, d a d u r c h g e -k e n n z e i c h n e t that the anchor head (1) at its end protruding into the borehole (6) a certain distance extending into the borehole free play tube (16) is. whose end pointing towards the end of the borehole is closed by a synthetic resin plug (17) is through which the reinforcement elements (7, 8) are passed, the anchor head has at least one outer sealing ring (10), under which a filling channel (14) or a filling pipe (25) passes through which can be filled with synthetic resin Clamping space (15) leads. 2. Mountain anchor according to claim 1, characterized in that the Free play tube (16) consists of synthetic resin. 3. rock anchor according to claim 1 or 2, characterized in that the free play tube (16) flexible and corrugated or roughened on its outside is. 4. rock anchor according to one of claims 1 to 3, characterized in that that the length of the free play space (18) is about a quarter of the length of the rock anchor amounts to. 5. rock anchor according to claim 4, characterized in that the reinforcement elements (7; 8) protrude from the free play tube (16) to the end of the borehole. 6. rock anchor according to one of claims 1 to 5, characterized in that that the reinforcement elements (7, 8) by a special production process on their Surface are roughened and that at least one of the reinforcement elements as an both ends spliced, glass fiber reinforced synthetic resin rod (8) formed is. 7. rock anchor according to one of claims 1 to 6, characterized in that that the reinforcement elements (7, 8) are located between their in the clamping space (15) Section and its located in the area of the threaded end of the anchor head (1) Section are preloaded. 8. rock anchor according to one of claims 1 to 7, characterized in that that one of the reinforcement elements as a ventilation pipe (7), which at his in the end of the borehole located end has additional ventilation slots (12) is formed. 9. rock anchor according to one of claims 1 to 8, characterized in that that in addition to the filling channel (14) or the filling pipe (25) one on the outside of the anchor head (1) below the sealing ring (10) is provided through ventilation channel (19). 10. Rock anchor according to one of claims 1 to 9, characterized in that that filling channel (14) or filling pipe (25) and optionally ventilation channel (19) the lower end of the anchor head (1) are arranged. 11. Rock anchor according to one of claims 1 to 10, characterized in that that the filling channel (s) (14) and optionally the ventilation channel (s) (19) to about reach to the center of the anchor head (1) or are only milled there. 12. Rock anchor according to one of claims 1 to 11, characterized in that that the filling channel (s) (14) and the ventilation channel (s) (19) in the outside of the Anchor head (1) are incorporated. 13. Rock anchor according to one of claims 1 to 12, characterized in that that the sealing ring (10) as a sealing collar with approximately frustoconical, stepped, annular lamellae is formed. 14. Rock anchor according to one of claims 1 to 13, characterized in that that in the anchor head (1) a not passed through the synthetic resin plug (17) Filling pipe (9) or a filling channel (26) for filling the free play space (18) is arranged is. 15. Rock anchor according to one of claims 1 to 14, characterized in that that in the anchor head (1) another not passed through the synthetic resin plug (17), however, vent pipe (13, 27) reaching to the end of the free space Ventilation of the free play space (18) is arranged. 16. Gebrig anchor according to one of claims 1 to 15, characterized in that that the free play tube (16) is pulled over the anchor head (1) to the mouth of the borehole is, between the borehole wall and the outer wall of the free play tube, a filling tube (25) from the mouth of the borehole to the clamping space (15) and the anchor head a groove or filling channel (26) leading from the mouth of the borehole to the clearance space (18) and a clearance space vent pipe (27) which emerges at the borehole mouth. 17. A method for setting a rock anchor according to one of the claims 1 to 16, characterized in that one is in the anchor head and that on this subsequent free play tube inserts the reinforcement elements, they in this and in the open end of the free play tube with the creation of a synthetic resin plug liquid, cold-curing synthetic resin, then the anchor head with the the free play tube protruding ends of the reinforcement elements ahead into the borehole introduces, with at least one sealing ring the gap between the borehole mouth and anchor head closes, whereupon you use a cranked injection needle that you insert into the Filling channel (s) or the filling pipe on the outside of the anchor head under the sealing ring introduces, presses liquid, cold-curing synthetic resin into the clamping space until this from the ventilation pipe and / or the ventilation channel on the outside of the anchor head emerges, after the resin has hardened, the reinforcement elements with the desired Pretensions force, fills the free space with liquid, cold-curing synthetic resin, the synthetic resin filled in the free space can harden, and then the anchor plate tightening against the mountains by means of the tension nut. 18. The method according to claim 17, characterized in that the Tensioning the reinforcement elements by means of the anchor plate and the tension nut makes. 19. The method according to claim 17 or 18, characterized in that the reinforcement elements only in an outer end area of the anchor head Fastened by potting and after the anchoring in the borehole, the pretensioning by means of a pressure tube pushed over the anchor head and the anchor head after the pretensioning and potting of the clearance space removed from the borehole.