JPS5942799B2 - Lock anchor and its fixing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a cylindrical metal anchor head, which can be removed after fixing the anchor if necessary, and which extends into the borehole to a predetermined depth and projects from the borehole. the anchor head having an external thread and a nut at its end for tightening the anchor plate and further surrounded by at least one sealing ring sealing the borehole in the area of the borehole; The present invention also relates to a lock anchor having at least one bar-shaped or cylindrical reinforcing member made of glass fiber-reinforced plastic that projects toward the end of the drilled hole.

When securing and preserving rock formations consisting of fragile rock, the installation of tensionable rock anchors is desirable and necessary for durable final reinforcement.

At the same time, the necessary restraining and supporting effects should be adjusted early and quickly to counteract the rock pressure or rock mass deformation, thereby achieving rapid stabilization of the hollow space or long-term rock preservation.

Indeed, even with the locking anchor disclosed in German Patent Application No. P 2 624 559, it is possible to tension the time that passes during the curing of the synthetic resin at the drilling end on the one hand and at the drilling opening on the other hand.

However, in that case the tensionable play space of the anchor reinforcement member cannot be fully utilized.

Moreover, this initial stress can no longer be adjusted after curing.

Therefore, underlying the present invention is the problem of providing a rock anchor as mentioned in the introduction, which has a length range that corresponds to the customization of the material, and in which the lock anchor can be freely selected. can be tensioned to the desired tension value.

This problem is solved by a lock anchor as mentioned at the outset, in which the anchor head 1 is connected at its end, which projects into the borehole 6, to a free play tube 16, which projects a predetermined distance into the borehole. and the end of the free-play tube facing the drilling end is closed by a synthetic resin plug 17, through which reinforcing elements 7, 8 pass, the anchor head 1 having at least one sealing ring 10; anchor head 1
It is characterized in that a filling groove 14 or a filling tube 25 passes through the outside, which groove or constriction tube opens into a tension space 15 which can be filled with synthetic resin.

The rock anchor according to the invention is resistant to corrosive effects, encroaching mineral waters and acids and is insensitive to stray currents.

When inserting into the hole, even if the hole contains water,
This rock anchor will not escape from the bedrock.

The hardening of the anchor takes place even when submerged in water, the hardening time being very short and the full supporting capacity being quickly achieved.

Escape from the perforation is not possible due to the type of filling material and the sealing material used, in contrast to normal filling materials.

This new anchor connects very well with the surrounding rock, penetrates into the undulating surface of the rock, and has a high elastic extensibility.

The restraining and supporting action of this anchor is therefore effective throughout its entire length.

The metal anchor head can be removed, so that the tensioned anchor can also be used when a later expansion of the shaft or milling is planned.

This anchor is particularly useful for final reinforcement work.

At the same time, with a new and tense rock anchor,
The entire range of full elastic extensibility of the synthetic resin with glass fiber reinforced reinforcing elements can be utilized in a precisely controlled manner for the initial stress.

In this case, the creep tendency present in the epoxy resin is favorable for the initial stress and strength properties of the anchor.

The epoxy resin elastically transfers rock pressure to the high tension glass fibers, which provide the anchor with its high working conditions to stabilize the rock.

The locking strength of the lock anchor against the resin and reinforcing member is increased by indentations or other undulations in the long surface of the anchor head.

Similarly, the synthetic resin is in particularly close contact with the surrounding rock or with the perforation wall.

The resilient laying of reinforcing elements in a synthetic resin as a connection element with the rock can be much more deformable and have a significantly higher load capacity than, for example, cement mortar between a steel anchor and the rock. It's clear.

In the embodiment according to claims 4 and 5, the length of the reinforcing element projecting through the free play space is approximately 1/4 of the overall length of the anchor.

This length ratio has proven to be particularly advantageous.

If glass fiber rods are used as reinforcing elements, a particularly good retention of the reinforcing elements can be achieved both in the anchor head and in the tension space with the embodiment according to claim 6.

In particular, it is preferable to generate the initial stress of the lock anchor between these points.

In the case of the embodiments according to claims 8 and 9, it is provided that air and, if appropriate, water also escape from the borehole during the press-in of the liquid synthetic resin via the exhaust pipe or the exhaust groove of the anchor head. Can be done.

This results in a complete filling of the tension space, during which the entire circumference of the borehole is likewise filled and sealed against water penetration.

The embodiment according to claim 10 is particularly advantageous if the anchor head is to be removed from the borehole again depending on the initial stress generated.

In this case, the anchor head is pushed into the borehole only up to the mark of elongation of the reinforcing iron under initial stress, which is 2 inches of the length of the free clearance space.

The filling and exhaust grooves may in this case be made correspondingly shorter.

(Claim 11) More expediently, the filling groove is provided on the outside of the anchor head like the exhaust groove (Claim 12).

However, the formation of these grooves could also be inside the sealing ring.

In order to optimally tighten the sealing ring against the perforation wall and ensure a good seal, the sealing ring is designed according to claim 13.

The arrangement of the filling pipe and the exhaust pipe (claims 14 and 15) ensures a complete and satisfactory filling of the free gap space.

Just as a curved injection needle is most expediently used when filling a tension space via a filling groove (also for filling a free gap space using a filling tube or a filling groove) Most preferably an injection needle or filling probe is used.

A particularly preferred rock anchor embodiment for heavy anchors (
In the case of claim 16), - the free clearance tube extends from the outside of the anchor head to the borehole, and the filling tube extends from the borehole between the borehole wall and the outer wall of the free clearance tube. The anchor head also has a notch or filling groove leading from the bore hole to the free play space, and the exhaust pipe of the free play space preferably reaches close to the thread of the anchor head and reaches the drill hole. It sticks out laterally.

The procedure for inserting the new locking anchor into the borehole is extremely simple.

In particular, a stiff lock anchor may be inserted through the anchor head without the need for special support equipment, since a conical sealing ring, preferably shown in FIG. 5, holds the anchor within the borehole.

The reinforcing elements for the free-gap space (glass fiber tubes and fiberglass rods) and, if necessary, the filling and exhaust pipes are hardened with epoxy resin in the anchor head, and the reinforcing elements are also solidified at the ends of the free-gap tubes. Molded and sealed with epoxy resin.

If the head of the rock anchor is to be removed after installation of the anchor and initial stress development, it is only necessary to cut it off from the solidified rond in the free play space by cutting.

Since the synthetic resin is hardened both in the tension space and in the free play space, the anchor itself remains under stress.

The fixing of the reinforcing element in the anchor head as well as in the free-play tube is advantageous since the final product produced in this way is free to be used for the installation of a locking anchor, which has already been installed previously. Good too.

The initial stress of the reinforcing element may then be generated by a separate device or by an anchor plate and a threaded nut.

This new rock anchor is performance-mentioned with respect to tunnel statics and rock wall mechanics aspects and is preferably suitable for rock wall construction and tunnel construction.

The supporting capacity of this anchor has been tested and proven in the range of 8 to 50 megapounds over lengths of 4 to 8 meters, also tested.

Its load capacity is actually quite large, reaching up to 100 mega-pounds.

It has a length of up to 20m or more, as long as you need it.
and can be obtained by adjusting the reaction rate of the filled resin.

The initial stress that can be generated has been tested in the range 10 to 15 megapounds, but may be significantly increased by the reinforcing elements.

The synthetic resin to be filled is preferably an epoxy resin, the curing time of which is from 4 to 45 minutes, within which time the epoxy resin becomes completely hard.

This short curing time allows a fast and uninterrupted implementation of the anchor work, as well as rapid work of the mooring force against rock fluctuations.

Epoxy resins are insoluble in mineral water and acids and are liquid tight.

In terms of manufacturing price, this new anchor has to be compared with anchors of the same performance, including all the expenses for the high corrosion resistance of known anchors.

In addition to the technical advantages, the price advantages of this new anchor then become apparent.

Next, the present invention will be described in detail based on embodiments with reference to the drawings.

The anchors of Figures 1 and 2 are designed for a tensile force of 30t and an initial stress of 15t.

This anchor has a cylindrical steel anchor head 1, on the threaded end 2 of which protruding from a borehole 6, an anchor plate 4 can be pushed, which plate has a threaded nut 31/i: thus a rock 5 can be fixed to.

The anchor head 1 has a recess 22 or a deformed portion in the shape of an annular structure and an annular path in its wall in order to increase restraint friction against the synthetic resin filled surrounding the head.

Into the borehole 6 -\ into the end of the anchor head 1 into which it enters, a free clearance tube 16 is pushed.

This tube is made of synthetic resin and is flexible or has its surface roughened or grooved in order to increase the restraining friction against the synthetic resin to be filled. It may also be polyurethane.

The end of the free-flow tube 16 facing the perforated end is closed by a molded plug 17 made of epoxy resin, through which reinforcing elements 7, 8 of synthetic resin reinforced with glass fibers pass through. ing.

In the case of this reinforcing member, one glass fiber reinforced plastic exhaust pipe 7 and one to two or more GFK rods 8 are used.
(Glass fiber reinforced plastic rod) is important.

These reinforcing elements 7, 8 extend over the entire length of the lock anchor, i.e. from the threaded end 2 of the anchor head 1, which is hardened with epoxy resin, through the anchor head 1 or through the free-play tube 16 to the drilling end, which The reinforcing element projects further from the clearance tube to the end of the borehole.

The reinforcing members 7, 8 pass through the synthetic resin plug 17 in a sealed state, and the insertion connection of the free play tube 16 of the anchor head is sealed, if necessary, using an adhesive bond or the like.

Thus, the volume of the borehole 6 occupied by the lock anchor is divided into an external space, i.e., a tension space 15 surrounding the anchor head 1 and the free-play pipe 16, and an internal space, i.e., the anchor head 1 and the free-play pipe 16. Internal free play space 1
8, the free play space 18 may be defined by synthetic resin plugs 17 and 28.

A tension space 15 is formed in the area of the drilling hole by the anchor head 1
Sealing is achieved by at least one sealing ring, preferably a conical ring 10, placed around the borehole 6, which ring has a sealing shoulder that lies close to the wall of the borehole 6.

In order to fill the tension space 15 with a liquid synthetic resin that hardens when cold, such as an epoxy resin, a filling groove 14 is formed on the outside of the anchor head 1 along the guide line.
The groove passes under the sealing ring 10.

The synthetic resin is charged into this filling groove via a bent injection needle 20.

In order to fill the tension space 15 satisfactorily and completely,
The exhaust pipe 7 is formed with an exhaust slot 12, and the outside of the anchor head 1 is provided with one or more exhaust grooves 19.
, which grooves are designed and arranged to resemble filler grooves 14.

A particularly preferred embodiment for anchors with high tensile strength (e.g., greater than 50-100) is shown in FIG.

In this embodiment, the free-play tube 16 extends outside the anchor head 1 to the perforation opening, and between the perforation wall and the outer wall of the free-play tube, a filling tube 25 communicates from the perforation mouth to the tension space 15. , and the anchor head has a notch or filling groove 26
, the groove leads from the perforation to the free play space 18;
Furthermore, the exhaust pipe 27 of the free play space extends at the borehole, preferably close to the threaded end of the anchor head, and exits laterally.

In this embodiment, the tension space 15 between the perforation wall and the lock anchor is filled with epoxy resin by means of a filling probe 24 through an injection tube 25 .

The injection tube 25 is located between the perforation wall and the outer wall of the free-play tube.

This injection tube leads from the borehole through the sealing ring 10 during the borehole.

Injection of the epoxy resin into the free play space is preferably carried out in this embodiment through a notch or filling groove 26 in the anchor head, which groove preferably starts near (and starts from) the threaded end of the anchor head. , and the epoxy resin is injected using a curved filling probe 23.

The free clearance space is evacuated in this embodiment by means of an exhaust pipe 2T, which exits between the anchor head free clearance pipe and the anchor head free clearance pipe.

This arrangement of the filling and evacuation mechanism helps that, especially in the case of heavy anchors, the resin cross-sectional area of the head of the anchor does not have to be reduced or restricted.

A shorter filling tube 9 to facilitate filling of the free play space 18 inside the anchor head 1 and the free play tube 16
or notches 26 and longer exhaust pipes 13 or 2
7 is disposed within the anchor head 1 or free play pipe 16, and the exhaust pipe reaches approximately from the threaded end or perforation opening of the anchor head 1 to the synthetic resin plug 17 that closes the free play pipe 16. .

Accordingly, the free gap space 18 is filled using filling probes 21 to 23 through the filling tube 9 or through the recess 26.

The tension space 15 is completely filled with liquid synthetic resin in the exhaust pipe 9.
This becomes clear when the gas exits from the exhaust groove 19.

Similarly, complete filling of the free space 18 is indicated by the exit of liquid synthetic resin from the exhaust pipes 13 to 27.

In order to improve the restraint friction of the rod-shaped reinforcing element 8 of glass fiber-reinforced synthetic resin, this glass fiber rod is provided with a split section 11 at its end.

For the same reason, the glass fiber tube 7 and the glass fiber rod 8
is roughened over its entire surface using a special manufacturing method.

In the embodiment of FIG. 3, instead of two glass fiber rods 8 as in FIGS. 1 and 2, four glass fiber rods 8 are provided.

This lock anchor is designed for a tensile force of 50t and an initial stress of 20t.

A more robust embodiment of the lock anchor is shown in FIG. 4, in this embodiment comprising ten fiberglass rods 8.

This embodiment of the rock anchor is designed for a tensile force of 100t and an initial stress of 30t.

Note that the same reference numbers indicate the same parts in all drawings.

The free clearance space 18 is, for example, already filled with synthetic resin in the cross-sectional views (FIGS. 2 to 4) and is therefore illustrated with parallel hatching.

Install a new lock anchor as follows.

The anchor head 1 is inserted into the borehole together with the molded reinforcing element 7+8 and the fixed free-sweep tube 16, the reinforcing element being similarly sealed off at the end of the free-sloshing tube by molding.

The connection point of the free clearance pipe 16 is sealed with an adhesive bond or the like.

The reinforcing rod is then passed through the free-play tube into the filling space or tensioning space 15 of the borehole 6, extending approximately 1 part of the entire length of the anchor.
/4 protruding 0 curved filling sonde 20 to 24
Using this, the tension space 15 is then filled through the filling groove 14 or the filling tube 25 which passes under the sealing ring 10.

The synthetic resin, which is in liquid form and is to be filled in cold, first flows into the anchor head 1 and then along the free gap pipe 16 into the space at the end of the borehole 6.

Air and optionally water can escape from the borehole during filling first through the exhaust pipe 7 and then through the exhaust groove 19 of the anchor head 1.

After hardening of the synthetic resin filling, the reinforcing rod 7.8 is tensioned in the free play space 18 to the desired initial stress and the initial stress is adjusted.

After this initial stress and stability of the rock pressure has developed, in the free gap space 18, the filling tube 9 is filled using the injection needles 21 to 23.
Anchor head 1 through cutout or filling groove 26
The hole is filled with the same cold epoxy resin through the hole or through the hole.

After hardening of the resin in the free play space 18, the lock anchor is under stress and may be tightly fastened using the anchor plate 4 and the screw nut 3.

If the anchor head is to be removed from the borehole after the initial stress has been generated, then the anchor head is only slightly introduced into the borehole.

Accordingly, filling and exhaust grooves and sealing rings should be installed at the end of the anchor head facing the borehole.

In this case, the initial stress of the reinforcing member must be generated through the screw thread of the anchor head with the tightening screw pushed around the anchor head using a tube and the tightening nut. is acting on an anchor plate set in a rock.

The initial stress generated in the free gap space and after filling and hardening,
The number of screws required for each screw can be further reduced.
The anchor head may also be removed by separating it from the reinforcing rod.

At the same time, the tensioned anchor does not contain any steel members, and due to the high retention and supporting action of hardened epoxy resin with glass fiber reinforcement members, the tensioned anchor is an ideal final reinforcement work for rock preservation over its entire length, against long-term rock movements. So effective, the anchor is a complete corrosion protection device.

[Brief explanation of the drawings] Figure 1 is a central cross-sectional view showing the lock anchor inserted into the borehole before filling with synthetic resin, and Figure 2 is a cross-sectional view of the lock anchor taken along the ■-■ plane in Figure 1. , FIG. 3 is a cross-sectional view corresponding to FIG. 2, and FIG. 4 is a cross-sectional view corresponding to FIG. A cross-sectional view corresponding to FIG. 2 showing another embodiment of the locking anchor for higher initial stress and tension than the anchor of FIG. 3; FIG. 5 a side view of the sealing ring; FIG. 6 a perforation. FIG. 7 is a central sectional view showing a particularly high tensile force lock anchor inserted into the lock anchor, with the free play tube 16 extending outside the anchor head 1 up to the borehole, FIG. I of
FIG. 8 is a cross-sectional view corresponding to FIG. 7 showing another embodiment of the lock anchor with an increased reinforcing element; FIG. DESCRIPTION OF SYMBOLS 1... Anchor head, 6... Perforation, 7, 8... Reinforcement member, 10... Sealing ring, 14... Filling groove, 1
5...Tension space, 16...Free play gap, 1T...
Synthetic resin plug, 25...filling tube.

Claims (1)

[Scope of Claims] 1. A rock anchor having a cylindrical metal anchor head that can be removed after insertion of the anchor if necessary, the anchor head projecting into the borehole to a predetermined depth, and The end protruding from the drilling hole has a male screw thread and a nut for tightening the anchor plate,
Furthermore, in a rock anchor having at least one elongated glass fiber reinforced plastic reinforcing member which seals the borehole in the area of the borehole and which is surrounded by a sealing ring and which is arranged in the anchor head and projects towards the borehole end. , the anchor head 1 has a free play space 18 at its end projecting into the borehole 6 and is connected to a free play space 16 projecting a predetermined distance into the borehole, the free play tube pointing towards the end of the borehole. The end of the synthetic resin plug 171'i1
m, through which reinforcing members 7, 8 pass, the anchor head 1 is closed by its internal filling and evacuation mechanism 14,
25°7.19, 9, 26, 27 and less (both 1
Lock anchor having a sealing ring 10, characterized in that a filling mechanism 14.25 passes outside the anchor head 1, which opens into a tension space 15 which can be filled with synthetic resin. 2. The lock anchor according to claim 1, wherein the free play tube 16 is made of synthetic resin. 3. The free play pipe 16 is flexible (and its outer surface is uneven).
Lock anchor as described in section. 4. The lock anchor according to any one of claims 1 to 3, wherein the length of the free play space 18 is approximately 1/4 of the length of the lock anchor. 5. The lock anchor according to claim 4, characterized in that the reinforcing members 7, 8 protrude from the free clearance pipe 16 to the perforation end. 6. A patent claim characterized in that the surfaces of the reinforcing members 7 and 8 are roughened, and at least one of the reinforcing members is formed as a glass fiber-reinforced synthetic resin rod 8 split at both ends. The lock anchor according to any one of the ranges 1 to 5. 7. The lock anchor according to any one of claims 1 to 6, wherein the reinforcing members 7 and 8 extend from the threaded end 2 of the anchor head 1 to the tension space 15. 8 One of the reinforcing members is formed as an exhaust pipe 7, which exhaust pipe has an additional exhaust slot 1 at its end at the perforated end.
The lock anchor according to any one of claims 1 to 7, characterized in that the lock anchor has: 9. In addition to the filling mechanisms 14 and 25, an exhaust groove 19 passing between the anchor head 1 and the sealing ring 10 is provided, according to any one of claims 1 to 8. rock anchor. 10. A lock anchor according to any one of claims 1 to 9, characterized in that the filling mechanism (14, 25) and the exhaust groove (19) extend from the threaded end (2) of the anchor head (1). 11. The lock anchor according to any one of claims 1 to 10, wherein the filling mechanisms 14, 25 and the exhaust groove 19 reach approximately the center from the threaded end of the anchor head 1. . 12. The lock anchor according to claim 1, wherein the filling mechanisms 14, 25 and the exhaust groove 19 are provided outside the anchor head 1. 13. A lock according to any one of claims 1 to 12, characterized in that the sealing ring 10 is formed as a sealing sleeve by a stepped cylindrical thin plate having a conical shape. Anchor. 14 In the anchor head 1, the synthetic resin plug 17
According to any one of claims 1 to 13, the filling mechanism 9, 26 which does not pass through is arranged inside the free play pipe 16 for filling the free play space 18. The described lock anchor 615 in the anchor head 1 does not pass through the synthetic plug 17 but in the free play space 18
Another exhaust pipe 1B, 27 reaching the end of the free play space 1
15. The lock anchor according to any one of claims 1 to 14, wherein the lock anchor is disposed inside a free play pipe 16 for exhausting air. 16 The free clearance pipe 16 extends from the outside of the anchor head 1 to the perforation opening, and between the perforation wall and the outer wall of the free clearance pipe 16, a filling pipe 25 communicates from the perforation opening to the tension space 15, and further extends from the anchor head 1 to the tension space 15. A filling groove 26 leading from the drilling opening to the free play space 18 and a free play space 18 extending from the drilling opening.
The lock anchor according to any one of claims 1 to 15, characterized in that it has an exhaust pipe 27. 17 Insert a reinforcing member into an anchor head and a free-play pipe having a free-play space inside and connected to the head, and insert the reinforcing member into the open end of the free-play pipe in a liquid state and when cold. A locking anchor is used which is hardened by making a plug out of a hardening synthetic resin, and the anchor head is introduced forward into the borehole with the end of the reinforcing member projecting from the free play tube, at least one Close the gap between the borehole and the anchor head with a sealing ring, and then use a curved radial nozzle that is introduced into the filling mechanism outside the anchor head and below the sealing ring to fill the liquid. Pressing a synthetic resin that hardens when cold into the tension space, tensioning the reinforcing member to a desired tension after the synthetic resin hardens, and filling the free gap space with a liquid synthetic resin that hardens when cold. A method for securing a lock anchor in a borehole, characterized by: