JPS5927839B2 - How to install a rock anchor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of installing rock anchors, particularly in water permeable rock.

It is known to incorporate rock anchors into boreholes that are fully filled with pre-drilled concrete mortar.

However, when making the perforation, a water-permeable layer is perforated, and the water flowing out through the anchorage hole then prevents the filling of the concrete mortar, since this plastic mortar is difficult to prevent the water flowing out, especially in the case of vertical perforations. This is because it is swept away from the perforation by the

This has heretofore required the creation of additional drainage boreholes which direct the simultaneously occurring mountain water from the original anchor borehole to the other.

Apart from the additional cost and loss of time, this method is also not always effective and the anchor drilling has therefore often had to be abandoned.

The invention aims at enabling a reliable installation of rock anchors under adverse conditions.

This means that during drilling a pressurized filler material, especially a hose permeable to concrete mortar, is installed, then the hose is filled with concrete mortar, and then the anchor bolt is inserted into the hose. The concrete mortar is then forced out through the hose to achieve a bond between the rock, the concrete mortar and the anchor.

The invention therefore makes it possible to fill the anchor hole with concrete mortar without any problems, even though water is flowing out of the anchor hole.

Even if the borehole is fully filled with concrete mortar, water can flow out of the borehole due to the hose acting as a drainage system.

The concrete mortar now remains stuck in the drilling.

The hose for carrying out this method is characterized in that it is constructed of a porous material, for example woven, knitted, braided or crocheted, consisting of rubber, plastic, metal or spun yarn.

It is suitable here for the hose to have a wall thickness of at least 3 mm.

This hose, which is itself flexible, is stretched over the length of the borehole and through which the concrete
Mortar is introduced during drilling.

The end of the fabric hose lying at the deepest part of the borehole is fixed to an anchoring element, which completely prevents the fabric hose from coming out.

It is expedient if the anchoring element is constructed as a conical hollow body and the support claw is arranged so as to penetrate into the rock at its foot-side opening.

The mortar filling hose is now pushed into the borehole in a conventional manner with the fabric hose with the attached anchoring element extended beyond it and filled with concrete mortar in a known manner.

In order to secure the porous hose to the anchoring element, it is provided with an axially extending cut in its flattened conical top, which causes the conical jacket to be elastically tilted relative to the conical axis. It is subdivided into tongues, and these tongues tightly tighten the hose that has passed through it.

This is pressed against the wall of the borehole by the now exiting mortar due to the flexibility of the fabric hose, and the entire inner diameter of the fabric hose is filled with dense plastic concrete mortar.

An anchorage on the rock side of the fabric hose holds the mortar stationary in the borehole, while the filling hose is forced out of the borehole by the outgoing mortar.

Between the wall of the perforation and the mortar there is now an annular cavity at least 3 mm thick, bounded by a mesh of fabric hoses, through which the simultaneously occurring mountain water can flow unhindered, and Mortar will not be washed away from the hole.

A pointed anchor bolt can now be driven into this borehole filled with concrete mortar.

Due to the pressure created by the displacement, the plastic mortar is now forced through the mesh of the fabric hose, thereby creating a bond between the rock, concrete mortar and anchor rod.

Embodiments of the object of the invention are illustrated in the accompanying drawings.

According to FIG. 1, a porous hose 2 is arranged in the borehole 1, which hose is held in the deepest part of the borehole by an anchoring element 3 so that it cannot fall out.

The hose 2 is brought in together with the filling hose 4 for the concrete mortar 5, the hose 2 being stretched over the hose 4 and pushed into the borehole.

When the now pressurized concrete mortar 5 is poured, the hose 4 is forced out of the borehole depending on the degree of filling.

However, the hose 2 remains inside the borehole 1 since it is detained by the anchoring element.

The water coming out of the rock drips between the walls of the borehole and the outside of the hose 2, but does not wash away the concrete mortar.

Depending on the type of material the hose is made of, water may also drain into the porous hose wall.

Does it have a hollow chamber passing through it, for example?
Or if the hose 2 is made double-walled.

Once the filling process according to FIG. 1 has been completed, the anchor 6 is driven into the borehole (FIG. 2).

The anchor 6 then acts like a piston which displaces the concrete mortar 5, so that the porous hose 2 is pressed against the rock.

This pressure also permeates the concrete mortar 5 through the network of the porous hose 2, so that the anchor 6 becomes intimately and firmly bonded to the rock via the concrete mortar 5.

The hose 2 is made of a reticulated knitted yarn fabric and has a wall thickness of at least 3 mm.

Twisted or wrapped materials are also possible, in which case the threads may also be made of plastic, metal, rubber or cast material.

Foamed materials with open pores can also be used.

If the gaps between the threads, or even the internal cavities that may exist, are small, they will flow into the hose wall due to surface tension.

The internal cavity is created, for example, by helically forming the thread or by making it into a double-walled hose.

The anchoring element 3 according to FIGS. 3 and 4 is designed in the form of a hat.

It consists of a substantially frustoconical base body, on the foot end of which are arranged supporting claws 7, which allow the anchoring element to be pushed in, but do not prevent its withdrawal. ing.

Cuts are cut in the top of the cone, which subdivide the conical envelope into tongues 8.

Due to the material used (for example plastic) the tongue 8 has a spring effect.

When the hose end now passes through the upper opening 3 of the anchoring element 3 formed by the tongue 8 in the sense of a funnel tube, the hose 2 is detained as by a latch lock.

This situation can be seen in FIGS. 1 and 2, in which the hose end tensioned by the anchoring element 3 has a mushroom-like configuration.

FIG. 5 shows an alternative anchoring element, which is of flat design and has a wedge-shaped gap 9 for fastening the hose 2 to the wall.

Many support claws 10 are arranged above and below on the outside.

A construction of two interconnected elements according to FIG. 5 is also possible.

[Brief explanation of the drawing]

FIG. 1 shows a borehole with a forced porous hose being filled with concrete mortar. Figure 2 shows a hose filled with mortar during anchor driving. FIG. 3 shows a cross-sectional view of an anchoring element for use with a hose such as that shown in FIGS. 1 and 2. FIG. FIG. 4 shows a plan view of the anchoring element according to FIG. FIG. 5 shows a modified structure of the anchoring element. In the figure, 1...
...Perforation, 2,4...Hose, 3...
... Anchoring element, 5 ... Concrete mortar, 6 ... Anchor, 7.10 ... Supporting claw, 8 ... Tongue, 9. ·····gap.

Claims (1)

[Claims] 1. During drilling, a hose permeable to the pressurized filling material, especially concrete mortar, is installed, then the hose is filled with concrete mortar, and then the anchor bolt is inserted into the hose. A method for installing a rock anchor in a rock, in particular permeable to water, characterized in that the concrete mortar is poured into the interior, and the concrete mortar is squeezed out through the hose to create a bond between the rock, the concrete mortar and the anchor. .