EP2251526B1 - Self-drilling anchoring element - Google Patents

Description

The invention relates to a self-drilling fastener, in particular a self-drilling rock anchor for chemical anchoring in a subsurface, such as a mountain or a component, for. B. of a mineral material, such as concrete or masonry.

Such fasteners, such. As a rock anchor, serve to stabilize the walls of cavities, such as tunnels, galleries and the like, in such a way that adjacent to the wall mountain areas are secured together. In many cases, it is assumed that areas that are impaired in the immediate vicinity of the wall as a result of the creation of the cavity in their mechanical properties, in particular in their carrying capacity, are attachable to more remote, undamaged mountain areas. In this context, the term wall of cavities, in addition to the ceiling section and the sidewalls of the cavity, also means its bottom area. Furthermore, such fastening elements can also be used for connections for the transmission of high loads.

In the chemically anchored fastener according to the US 4,303,354 A two tubular bags with masses of different hardnesses are introduced into a previously created borehole, of which the tubular bag facing the borehole bottom contains a rapidly hardening composition and the tubular bag adjoining it has a comparatively slower curing composition. When inserting the fastener first the tubular bag is destroyed with the slow-curing composition and mixing the components contained therein to a first mixture of the curable composition. Subsequently, the tubular bag is destroyed with the fast-curing composition and the components contained therein mixed into a second mixture of the curable composition, which begin to cure immediately.

A disadvantage of the known solution is that first with a separate tool, a borehole must be created and the insertion of the two tubular bag is expensive in each hole. In addition, the tubular bag may be inadvertently introduced into the well in the wrong order, so that upon insertion of the fastener first the tubular bag is destroyed with the rapidly curing composition and thus the correct setting of the fastener is no longer or only limited possible.

From the US 4,055,051 A is a generic self-drilling fastener known factory-equipped with the mass to be compacted and is easier to set. The fastening element has a hollow cylindrical receiving body which is provided at one end with a drill head and in which an expressible, hardenable multicomponent mass is provided. The curable composition comprises a hardener and a reactive resin, which are stored separately from each other and cure in the mixed state. In the drill head through openings are provided for the hardenable mass.

The fastener according to the US 4,055,051 is drilled in the underground. After reaching the desired setting depth, the z. B. in a foil bag curable mass pressed out by pressure, which is mixed through the passage opening in the drill head to a mixture and placed in the space surrounding the fastener. After curing of the hardenable mass, the fastener is chemically anchored in the ground.

Furthermore, the EP 0 163 019 a cartridge for multi-component wells for wells containing a hardness component and two different viscosity resin components.

A disadvantage of the known solution is that until the curing of the hardenable mass, the fastener is not resilient.

The object of the invention is to provide a chemically anchored fastener that is easy and safe settable and can be loaded quickly to a certain level.

The object is solved by the features of the independent claim. Advantageous developments are set forth in the subclaims.

According to the invention, at least the reactive resin comprises two different formulations which are arranged one behind the other, wherein the second formulation of the reactive resin, which cures rapidly in the mixed state with the at least one curing agent, is located behind the first formulation of the reactive resin with respect to the setting direction of the fastening element which hardens more slowly in the mixed state with the at least one hardener.

After complete compression of the components of the curable composition are two different fast curing mixture of the curing composition before. The first outflowing first mixture cures at moderate speed and ensures the afterflow of the second batch. The effluent after the first batch second batch hardens faster than the first batch and advantageous immediately. This ensures that the fastener is anchored faster and safer in the ground, with the fast-curing mixture comes to rest in the area of the bottom of the hole, which ensures an advantageous introduction of force into the ground.

In a variant of this, the reactive resin may also comprise more than two formulations which are arranged one behind the other. In this case, the first outflowing mixture of the hardenable mass has a curing rate which is slower than the curing rate of the second outflowing mixture, and corresponding to the second batch following further mixtures a faster cure rate than the second outflowing mixture.

Advantageously, the hardenable mass is factory provided in the prefabricated with the drill head fastener, whereby a secure application of the fastener is guaranteed on site.

For a thorough mixing of the components of the hardenable mass, a mixing element is advantageously provided between the components of the hardenable mass and the at least one passage opening in the region of the drill head. Alternatively or additionally, the passage openings in the drill head are designed such that when they pass through the components they are mixed with each other to a sufficient extent to the corresponding batch.

The self-drilling fastener can be used as an active anchor, d. H. as a prestressable anchor, as well as a passive anchor, d. H. as a non-preloaded anchor.

When Aktivanker by means of a biasing element already about the fast-curing mixture in the ground partially anchored fastener almost directly after the complete Auspressvorgang the hardenable mass prestressed. Due to the staggered post-hardening of the slow or moderately reactive first batch in the prestressed area, the pretensioning achieved during pretensioning of the fastening element is chemically fixed.

In the case of the passive anchor, the drill motor and the ejection unit can be removed immediately after the complete application of the components of the hardenable mass and a next fastener can be set, as the at least partial anchoring of the fastener is achieved immediately after the complete extrusion process of the hardenable mass.

The setting effort in an active anchor as well as a passive anchor is significantly reduced compared to the previously known versions of chemically anchored fasteners. Furthermore, due to the different curing speeds of the mixture, such fastening elements can be set more independently of the temperature of the substrate, with which the self-drilling fastening element according to the invention can be used flexibly, in particular in tunnels or tunnels. Normally, hardening compounds are used on cold surfaces and slowly hardening compounds on hot or warm surfaces. Since the inventive fastener has both these types of curing compounds, a secure anchoring of the fastener is guaranteed in different substrates.

Suitable hardeners for the, advantageously free-radically curable or curing reaction resins are peroxy compounds, in particular dibenzoyl peroxide, used. Advantageously, the same hardener is used in the fast as well as in the slowly hardening mixture.

The reactive resin is composed at least of a base resin, a reactive diluent and a hardening accelerator. Reactive resins for use in curable compositions for the chemical anchoring of fasteners are known and z. B. in the DE 42 31 161 or the US 4,518,283 disclosed. However, according to the invention, the curing time of the corresponding mixture is set by varying the ratios of these components to one another or the formulation of the reactive resin. The different curing time or curing rate of the two formulations of the reactive resin is significantly determined by the amount of curing accelerator. Suitable amines are, in particular, such as N, N-substituted anilines (for example N, N-dimethylanilene) or N, N-substituted para-toluidines (for example N, N-dimethyl-para-toluidine), but also Co-, Mn -Sn or Ce salts, such as cobalt octoate. Furthermore, both formulations advantageously have further fillers, such as. As quartz, glass and hollow glass spheres, corundum, chalk, talc.

The mixing ratio of the reactive resin with the first formulation and the curing agent and the mixing ratio of the reactive resin with the second formulation and the curing agent are advantageously the same and are from 1: 1 to 10: 1, advantageously from 3: 1 to 5: 1.

Preferably, the components of the curable composition are arranged in chambers of a tubular bag, which is easy to produce as a package and also can be easily arranged in the hollow cylindrical receiving body. Advantageously, the tubular bag is a film bag, which is further advantageously formed from a tailored to the chemical properties of the components of the curable composition, multilayer film.

Preferably, all components of the curable composition are arranged in a common tubular bag, which allows a simple production of the self-drilling fastener. The tubular bag is advantageously formed from a sheet material, which is folded to form the required number of chambers and welded accordingly.

Preferably, the different formulations of the reactive resin in a continuous, extending in the longitudinal direction of the tubular bag chamber of the tubular bag are arranged. In this arrangement of the components, the tubular bag in cross section has an advantageous small size and is easy to produce. To exclude an undesirable reaction of the formulations with each other during the storage condition of the fastener, a partition between the formulations is advantageously provided in the corresponding chamber of the tubular bag. The partition is advantageous, for. B. under pressure, easy to open or destructible.

Fig. 1

Ein erfindungsgemässes selbstbohrendes Befestigungselement in Form eines Gebirgsankers in einem schematischen Längsschnitt; und

Fig. 2

das selbstbohrende Befestigungselement im gesetzten Zustand.

The invention will be explained in more detail below with reference to an embodiment. Show it:

Fig. 1

An inventive self-drilling fastener in the form of a rock anchor in a schematic longitudinal section; and

Fig. 2

the self-drilling fastener in the set state.

Basically, the same parts are provided with the same reference numerals in the figures.

That in the FIG. 1 shown self-drilling fastener 11, here in the form of a rock anchor, has a hollow cylindrical receiving body 12, at a first, lying in the direction S end 13 a drill head 16 and at the opposite end 14 a rotary driving means 15, z. B. in the form of a detachable with a drill, not shown here, polygon. The drill head 16 has a first passage opening 17 and two radially outwardly open second passage openings 19. Further, a funnel-shaped, tapered to the free end of the drill head 16 receptacle 18 is provided in the drill head 16.

In the receiving body 12, an inner tube 21 is arranged, in which a packaged in a foil bag as a tubular bag 23, auspressbare and curable multi-component compound 26 is arranged. The multi-component mass 26 comprises a reactive resin 28 and a hardener 27, which are stored separately from one another and which cure in the mixed state. The hardener 27 is provided in the longitudinal extent of the tubular bag 23 extending, first chamber 24 of the tubular bag 23. The reactive resin 28 is provided in a second chamber 25 of the tubular bag 23 extending parallel to the first chamber 24 and comprises a first formulation 29 and a second formulation 30 different from the first formulation 29 or different from the first formulation 29. The first formulation 29 and the second formulation 30 are arranged one behind the other in the continuous, extending in the longitudinal direction of the tubular bag 23 second chamber 25 of the tubular bag 23. In order to exclude an undesirable reaction between the first formulation 29 and the second formulation 30 in the storage state of the fastening element 11, between the first formulation 29 and the second formulation 30 is a partition wall 33 which can be easily opened or destroyed under pressure in the second chamber 25 of the tubular bag 23 intended. The second formulation 30 of the reactive resin 28, which cures rapidly in the mixed state with the hardener 27, is arranged with respect to the setting direction S of the fastening element 11 behind the first formulation 29 of the reactive resin 28, which hardens more slowly in the mixed state with the hardener 27.

An example of the composition of the first formulation 29 of the reactive resin 28, the second formulation 30 of the reactive resin 28 and the hardener 27 are each set out below to illustrate the invention. These examples are not exhaustive.
Hardener 27: dibenzoyl 20.0% by weight water 30.0% by weight Quartz 0.01 to 0.03 mm 50.0% by weight
The first formulation 29 of the reactive resin 28, which forms a slowly hardening mixture 41 or mixture in the mixed state with the hardener 27. Unsaturated polyester resin 27.0% by weight styrene 18.0% by weight dimethylaniline 0.1% by weight chalk 52.9% by weight Pyrogenic silica 2.0% by weight
second formulation 30 of the reactive resin 28, which in the mixed state with the hardener 27 forms a rapidly hardening mixture 42 or mixture. Bisphenol A diglycidyl dimethacrylate 25.0% by weight B. 1,4-butanediol dimethacrylate 20.0% by weight dimethylaniline 1.0% by weight chalk 51.5% by weight Pyrogenic silica 2.5% by weight

The mixing ratio of the first formulation 29 of the reactive resin 28 with the hardener 27 as well as the mixing ratio of the second formulation 30 of the reactive resin 28 with the hardener 27 is 3 parts to 1 part (3: 1).

In the inner tube 21, a mixing element 31, which is displaceably mounted in the inner tube 21 and advantageously made of a plastic, is provided between the hardenable mass 26 and the drill head 16. At the opposite end of the mixing tube 31 of the inner tube 21, a squeezing piston 36 is provided in the inner tube 21 for squeezing the curable composition 26. Through the space between the inner tube 21 and the receiving body 12, a suction of cuttings or drilling dust or supplying rinse water to the drill head 16 is ensured.

The fastener 11 is, as in FIG. 1 shown as a whole with a drilling / ejection unit, not shown here, which is coupled to the rotary driving means 15 of the receiving body 12, drilled into the substrate 6.

After reaching the desired drilling depth pressure is applied via the squeezing unit 36, for example by means of water as Druckbeaufschlagungsmittel, wherein first the mixing element 31 is pushed in the direction of the drill head 16 until the free end of the mixing element 31 in the receptacle 18 of the drill head 16 to come to rest. Upon further pressurization of the mass 26 to be squeezed out via the squeezing piston 36, it flows out of the fastening element 11 through the passage openings 17 and 19 in the drill head 16.

The first slowly hardening mixture 41 first flows out of the fastening element 11 and fills the gap between the outer wall of the receiving body 12 and the borehole wall 7 from the bottom of the borehole. The subsequently flowing out second mixture 42, which hardens quickly, displaces the first mixture 41 further in the direction of the second end 14 of the receiving body 12. Due to the fast curing second batch 42, the fastening element 11 is anchored in the region of the borehole bottom after the pressing out of the hardenable mass 26 and at least limited, e.g. B. for biasing the same, resilient. After the time-delayed curing of the first batch 41, the fastening element 11 is completely anchored in the substrate 6.

Claims (2)

1. Self-drilling fastening element (11) for chemical anchoring in a base (6), comprising a hollow cylindrical receiving body (12) that comprises a drill head (16) at one end (13) and in which an ejectable, hardenable multicomponent substance (26) is provided, which comprises at least one hardener (27) and at least one reactive resin (28), which are stored separately from one another and harden when mixed together, and at least one through-opening (17, 19) for the hardenable substance (26) being provided in and/or in the region of the drilling head (16), characterised in that at least the reactive resin (28) comprises two different formulations (29, 30), which are arranged one behind the other, the second formulation (30) of the reactive resin (28), which hardens rapidly when mixed with the at least one hardener (27), being arranged, in the setting direction (S) of the fastening element (11), behind the first formulation (29) of the reactive resin (28), which hardens more slowly when mixed with the at least one hardener (27), the components of the hardenable substance (26) being arranged in chambers (24, 25) of a tubular bag (23) and all of the components of the hardenable substance (26) being arranged in a common tubular bag (23).
2. Fastening element according to claim 1, characterised in that the different formulations (29, 30) of the reactive resin (28) are arranged in a continuous chamber (25) of the tubular bag (23) which extends in a longitudinal direction of the tubular bag (23).

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