Hollow-rod composite anchor with adaptable dispensing of fastening material

Abstract

The present invention relates to a system for installing a hollow-rod composite anchor in rock layers, the system at least comprising: a hydraulic pressure-generating unit; and a hollow-rod composite anchor which can be hydraulically connected to the hydraulic pressure-generating unit and comprises a static mixing device, an adhesive cartridge having a plurality of compartments, and an ejection piston, wherein the ejection piston is designed in multiple parts in an axial direction and has ejection plungers which can be displaced in the axial direction independently of one another in the hollow rod, and a hydraulic flow divider is arranged between the pressure-generating unit and the ejection piston. The invention also relates to the use of the system according to the invention for securing rock layers in mining, tunnelling, civil engineering, and rock construction.

Description

[0001] Hollow bar composite anchor with adaptable fastener discharge

[0002] The present invention relates to a system for setting a hollow bar composite anchor in rock layers, comprising at least one hydraulic pressure generation unit and a hollow bar composite anchor hydraulically connectable to the hydraulic pressure generation unit, having a static mixing device, an adhesive cartridge with multiple compartments, and an ejection piston. The ejection piston is formed in several parts in an axial direction and has ejection stamps that can be displaced independently of one another in the hollow bar in the axial direction, and a hydraulic flow divider is arranged between the pressure generation unit and the ejection piston. Furthermore, the present invention relates to the use of the system according to the invention for securing rock layers in mining, tunneling, civil engineering, and rock construction.

[0003] The reproducible and permanent stabilization of unstable rock layers remains a challenging task from both a technical and economic perspective. Due to the increased stabilization requirements, for example in mining and tunneling, "robust" approaches have been the gold standard to date. These approaches are based on significantly oversized but always sufficient "one-size-fits-all" solutions, regardless of the specific rock conditions. In the field of stabilizing outer rock layers using anchors that can be chemically fixed into rock layers, this specifically means that anchors are used whose chemical fixation using adhesives or adhesives typically exceeds the holding forces required for stabilization by several times. This oversizing essentially concerns the design of the anchor dimensions and the adhesive systems and quantities used.The latter is advisable because the quality of chemical anchoring with the commonly used two-component adhesives depends heavily on the reproducibility of the extrusion process. Given the difficult-to-control boundary conditions in rock engineering, this inevitably leads to chemical anchor setting processes being carried out with relatively simple adhesive systems and geometries in order to minimize fluctuations in the strength achievable during the curing process. This is not only costly but can also prevent the use of more suitable adhesive systems that cannot be used reproducibly with existing anchors.

[0004] The patent literature also contains a wide variety of approaches to the use and design of chemically curing composite anchors.

[0005] For example, DE 10 334 374 A1 describes an ejection device for ejecting a mass from a self-drilling, chemical composite anchor for the construction sector, in particular for ejecting a mass from a self-drilling, chemical composite anchor for mining and tunneling, with a housing and a pressing device, wherein the composite anchor comprises an anchor tube which has one end with a drill head and a free end and can be drilled into the ground by means of a motor, wherein the anchor tube has a receptacle for the mass to be ejected and an ejection piston can be arranged in the anchor tube, characterized in that the ejection device is operatively coupled to the motor and the free end of the anchor tube.

[0006] DE 10 2006 006 748 A1 describes a two-step inliner hollow bar fully composite anchor for use in mining, tunneling, civil engineering, and rock construction for the safer and more cost-effective lining of cavities without additional aids such as internal channels for flushing or extracting drilling debris, and without an inner pipe as an adhesive magazine. The anchor has pre-assembled linear, layered, or cross-band cartridges embedded in the hollow bar, which are pressed into the annular space of the anchor borehole by a piston with a static mixing device for chemical curing. The pre-assembled pressure adhesive, in the form of a paste or granulate, reacts under pressure with the dispensing piston in the macro or molecular range with the hardener embedded in the adhesive without a mixing device during the dispensing process through a bursting valve, which triggers the curing of the adhesive mixture in the annular space of the borehole.In the safety end position, the ejection piston separates the pressurized water from the annular space and prevents unintentional further ejection of the adhesive mixture to the anchor base, which would lead to the weakening of the adhesive bond of the inliner hollow bar fully composite anchor in the borehole.

[0007] DE 10 2011 102 994 A1 discloses a rock anchor with an anchor tube, an anchor tip, a static mixer, and a cartridge. The cartridge is inserted into the anchor tube, and the cartridge has at least a first volume and at least a second volume, which are separated from one another by at least one partition and are each filled with an adhesive. The rock anchor is realized by providing a first ejection piston in the first volume of the cartridge and a second ejection piston in the second volume of the cartridge, such that the adhesive can be ejected from the first volume with the first ejection piston, and the adhesive can be ejected from the second volume with the second ejection piston, in the direction of the static mixer.

[0008] Such solutions known from the state of the art can offer further potential for improvement, in particular with regard to a flexible design of the adhesive systems that can be adapted to the existing rock situation, whereby in particular the pressing process of the individual adhesive components can be controlled very precisely and reproducibly.

[0009] It is therefore the object of the present invention to at least partially overcome the disadvantages known from the prior art. In particular, the object of the present invention is to provide an improved composite anchor and an improved method for installing a composite anchor in a rock layer, wherein, in particular, the ejection process of the adhesive systems used can be carried out more reproducibly, quickly, and reliably.

[0010] The problem is solved by the features of the independent claims, directed to the system according to the invention and the method according to the invention. Preferred embodiments of the invention are specified in the subclaims, in the description, or in the figures. Further features described or shown in the subclaims, in the description, or in the figures may constitute a subject matter of the invention, individually or in any combination, unless the context clearly indicates otherwise.

[0011] The object is achieved according to the invention by a system for setting a hollow bar composite anchor in rock layers, comprising at least one hydraulic pressure generating unit and a hollow bar composite anchor hydraulically connectable to the hydraulic pressure generating unit, wherein the hollow bar composite anchor has an anchor base with one or more outlet channels, a hollow bar arranged at the anchor base containing a static mixing device, an adhesive cartridge with several compartments and an ejection piston, wherein the ejection piston is designed in several parts in an axial direction according to the number of compartments of the adhesive cartridge and has ejection stamps that are independently displaceable in the hollow bar in the axial direction and are each adapted in a radial cross-sectional area to a compartment cross-section of the adhesive cartridge,A hydraulic flow divider is arranged between the hydraulic pressure generating unit and the extrusion piston, the hydraulic flow divider being configured to exert different hydraulic forces on each extrusion piston independently of one another. Surprisingly, it was found that rock layers can be secured flexibly and reproducibly using the system according to the invention. In particular, various adhesive systems adapted to the application situation can be used, which were previously not accessible with standard anchors. Due to the direct controllability of the extrusion process via individual pressure control for the individual components of the two- or multi-component adhesive, compartment-dependent, as a function of time,Different quantities of adhesive components can be applied. Due to the independent power transmission to each individual ram of the extrusion piston and the mechanical decoupling of the individual rams of the piston, each individual adhesive component can be precisely controlled in its flow. This is made possible by the use of a hydraulic flow divider, which can specifically distribute the integral pressure provided by the hydraulic pressure generation unit to the individual rams. These rams are moved independently of one another as a function of the respective pressure in the hollow rod and can thus specifically deliver specific quantities and ratios of adhesive components per unit of time through the static mixer into the rock. This arrangement is significantly more flexible than state-of-the-art solutions, which either use only one ram or offer only synchronously movable rams.which offer only a single pressure and ejection speed for all the adhesive components. In these state-of-the-art solutions, the individual adhesive components cannot be dispensed independently from the compartments. A further advantage of the inventive solution is that the individual ratios between the components can be variably controlled as a function of time, so that different mixing ratios between the components can also be adjusted in a single ejection process. This enables significantly better control of the composition of the adhesive mass and thus the achievable adhesive properties. The inventive system is a system for setting a hollow bar composite anchor in rock layers.The system comprises at least one hydraulic pressure generating unit and a hollow bar composite anchor hydraulically connectable to the hydraulic pressure generating unit. The system thus has a hydraulic pressure generating unit and a hollow bar composite anchor as its fundamental units. The pressure generating unit can, for example, be designed in the form of a compressor, which brings water from one pressure level to a higher one and makes this compressed water flow available in a targeted manner. Conventional pressure generating units, for example in the form of pumps, can be used. The basic structure of the pressure generating units is known to those skilled in the art. The pressure generating unit can preferably provide a hydrostatic pressure of greater than 50 bar, more preferably greater than 75 bar, and more preferably greater than 100 bar. The pressure generating unit can, for example, be connected to the hollow bar composite anchor via a hose system.which transmits the hydraulic pressure of the pressure generation system to the anchor. The hollow bar composite anchor used is suitable for stabilizing rock layers in mining, tunneling, civil engineering, and rock construction. Rock layers can be consolidated superficially by inserting anchors to prevent the accidental displacement of rock fragments or slabs. The composite anchors are inserted into anchor bores, which are drilled using wet or dry drilling methods depending on the rock hardness. The composite anchor comprises several components, with the anchor base and the other components usually arranged within a cylindrical hollow bar. The hollow bar can be made of metal, for example, steel. The hollow bar composite anchor is first inserted into the borehole at the base end and then pushed completely into the borehole using the hollow bar attached to it. It is possible tothat the hollow bar composite anchor is formed from a single hollow bar with an anchor base or from several hollow bars and an anchor base. The additional hollow bars can serve as an extension of the first hollow bar composite anchor via a mechanical connection option. The hollow bar composite anchor has an anchor base with one or more outlet channels, a hollow bar arranged at the anchor base containing a static mixing device, an adhesive cartridge with several compartments, and an ejection piston. The hollow bar composite anchor has at least one anchor base with one or more outlet channels. After installation of the hollow bar composite anchor, the anchor base is located at the deepest point in the borehole, and fasteners can be guided out of the anchor through the outlet channels into the surrounding rock. The emerging fasteners apply adhesive to the entire or at least a large part of the anchor on the outside.so that after setting, a firm connection is created between the hollow bar composite anchor and the surrounding rock layer. The outlet channels can be arranged symmetrically or asymmetrically on or in the anchor base, and preferably, the anchor base can have more than 2, furthermore preferably more than 3, and furthermore preferably more than 4 outlet channels.

[0012] A hollow bar is arranged behind the anchor foot, towards the borehole opening. The hollow bar with the other components of the hollow bar composite anchor can either be permanently connected to the anchor foot or can be designed so that it can be connected to it. For example, the hollow bar can be connected to the anchor foot using a screw, clamp, weld, or adhesive connection, or it can be connected to the anchor foot shortly before installation. In this way, variable anchor feet can be used depending on the rock type, or different hollow bars, for example with varying hollow bar volumes, can be used for fastening. The material of the hollow bar is preferably metal, furthermore preferably steel. Possible dimensions of the hollow bar range from approximately 50 cm to 6 m in length and 2.5 cm to 50 cm in diameter.

[0013] The hollow bar has a static mixing device. Starting from the bottom of the borehole, the anchor base extends first, followed by the hollow bar, which can be attached to this. The static mixing device is located inside the hollow bar adjacent to the anchor base. A static mixing device does not have any mechanically driven mixing elements. The mixing effect of the static mixer is essentially based on the forced guidance of the components to be mixed by the guide devices of the static mixer. The components to be mixed are therefore first passed through the static mixer, mixed there, and then leave the mixing device towards the anchor base. The mixed adhesive is fed through the outlet channels of the anchor base into the gap between the hollow bar composite anchor and the rock, where it then completely cures.The mixing device can preferably have an extension in the longitudinal direction of the hollow bar composite anchor of greater than or equal to 5 cm and less than or equal to 50 cm. The ratio of the mixer to the hollow bar composite anchor total length, expressed as the length of the static mixer unit divided by the length of the hollow bar composite anchor, can preferably be greater than or equal to 0.01 and less than or equal to 0.5. Within this range, good mixing results can be achieved while still maintaining sufficient adhesive volumes. A device for opening the parts of the adhesive cartridge can be arranged upstream of the mixing device. The adhesive cartridge can preferably have a bursting surface on the lower part towards the mixing device, which cooperates with the device for opening the adhesive cartridge. The bursting surface can be designed for the entire cartridge or, expediently, for each individual compartment.For example, the bottom surface of the adhesive cartridge can be made of metal, with the metal having an embossed pattern that contributes to a reduction in mechanical strength in the embossed area. When pressure is applied, these areas yield, allowing the cartridge to open precisely before the mixer.

[0014] The hollow bar composite anchor also features an adhesive cartridge with multiple compartments and an dispensing piston. The static mixer is filled with fasteners via a cartridge, whereby the fasteners can preferably be two-component or multi-component adhesives. In the case of a two-component adhesive, the two components can be referred to as hardener and binder. The two components are located within the adhesive cartridge and are separated from each other by walls, which prevents premature reaction between the individual components before ejection. The individual volumes within the adhesive cartridge, separated from each other by walls, form the compartments. The adhesive component(s) contained in the adhesive cartridge are partially liquefied by pressure applied to the dispensing pistons and forced towards the mixer.There, the components come into contact, are thoroughly mixed, and react, or either exit the hollow bar as such. The mixed adhesive exits the anchor base through the outlet channels and hardens between the anchor exterior and the borehole wall, partially or completely along the borehole length up to the anchor base. Additional functional components, such as a nut and / or an anchor plate, can be arranged on the hollow bar composite anchor, for example, at the anchor head. The anchor plate can be mechanically connected to the nut.

[0015] The dispensing piston is constructed in multiple parts in an axial direction, corresponding to the number of compartments in the adhesive cartridge. Depending on the number of individual compartments in the adhesive cartridge filled with adhesive components and separated from one another by walls, the dispensing piston each has individual means that selectively act on the respective compartment. If, for example, the adhesive cartridge has two separate chambers containing hardener and binder, the dispensing piston is constructed in two parts. If there are four compartments, the dispensing piston has four separate means for dispensing. In this context, the axial division of the dispensing piston indicates that the dispensing piston is divided lengthwise into the hollow rod and that the division does not occur radially as a radial cut through the piston.In the latter division, the piston would act on the entire internal cross-section, whereas with an axial division, several parts result, which can act independently on different cross-sectional areas of the hollow bar's internal cross-section in the direction from the borehole mouth to the anchor foot. The specifications axial and radial refer to the basic symmetry of the hollow bar. The division of the extrusion punch results in extrusion punches that can be moved independently of one another in the axial direction within the hollow bar and, in a radial cross-sectional area, each adapted to a compartment cross-section of the adhesive cartridge. The shape of the punches is designed so that the surface of a punch essentially only exerts forces on one compartment of the adhesive cartridge. The cross-section in the radial direction of each extrusion punch is therefore essentially adapted to the shape of the underlying compartment to be extruded.Other compartments containing additional or different adhesive components are essentially not mechanically influenced by the respective ram, since the ram, due to its position within the hollow bar and its cross-sectional area, cannot influence the other compartments of the adhesive cartridge. The individual rams are not mechanically coupled to one another, allowing them to move independently of one another within the hollow bar, i.e., within the respective compartment, from the borehole mouth or anchor head toward the anchor base. This mechanical independence is essential, as only in this case can an expiration speed adapted to the individual compartment be achieved. This allows even significantly different adhesive volumes to be reproducibly mixed.The stamps move within the respective compartments and the applied pressure is stabilized via the compartment walls so that a compartment-specific pressure is maintained even during the stamp movement.

[0016] A hydraulic flow divider is arranged between the hydraulic pressure generation unit and the extrusion piston. A hydraulic flow divider is attached to the hollow rod, the pressure generator, or between the hollow rod and the pressure generator. This divider divides the main hydraulic flow provided by the pressure generator into two or more flows, with the flows having different or the same pressure. The division is preferably carried out in such a way that at least two different flows result. The different flows can, for example, be flows of the same volume per unit of time. The partial flows can, for example, have a pressure that can differ by up to 80% or less. There are two basic designs for flow dividers. One is a piston flow divider or a gear flow divider. The piston flow divider is technically simpler.It is a branch piece without any additional technical components. The volume flow is introduced at one side and distributed into the sub-lines, usually via openings of different sizes. The incoming volume flow is divided as a function of the cross-sections of the sub-lines. A rotary flow divider, usually designed as a gear flow divider, has a more complex structure. This component has a small gear pump inside, which maintains the pressure and velocity of the incoming volume flow. Rotary flow dividers can have multiple outlets, so that pressure amplification or reduction and the distribution of the volume flow take place in a single component. The flow divider can also be designed as a Venturi flow divider. The individual outlets of the flow divider can be pressure-tightly connected to the individual compartments, in which the respective extrusion rams then move during the extrusion process.

[0017] The hydraulic flow divider is designed to exert different hydraulic forces on each dispensing ram independently of one another. The flow divider therefore has an inlet, which is fed via the hydraulic pressure generation unit. The number of outlets is a function of the number of compartments of the adhesive cartridge and, accordingly, also a function of the number of dispensing rams of the dispensing piston. If four dispensing rams and compartments are present, the flow divider has four outlets. The distribution of the main flow can be a function of the respective cross-sectional area of ​​the ram being acted upon and the corresponding compartment to be emptied, or, in particular according to the invention, a function of the adhesive volume to be emptied per unit of time.The different emptying speeds can be exerted and adjusted, for example, by applying different hydraulic forces to the respective punches. These different forces can be used, for example, to ensure that the individual punches move evenly or at uneven speeds during the extrusion process. If the individual punches have significantly different surfaces, the different surface friction of the punches can cause a punch with the larger surface to move more slowly with just one applied pressure. As a result, the desired mixing ratio of the adhesive components is no longer correct. This effect can be compensated for by applying different pressures and correspondingly different forces.With a volumetric mixing ratio of 1:1 for a two-component anchor adhesive, the flow rates of the flow divider should be the same for each compartment, so that the individual pistons run exactly parallel in the hollow rod. Because the walls of the compartments can be very thin, the pistons should run parallel in the compartments; this way, they stabilize each other, and the resulting supporting forces maintain the frictional seal between the piston and the compartment walls along the length of the extrusion path in the anchor.

[0018] In a preferred embodiment of the system, the hydraulic flow divider can be arranged on or in the hollow bar composite anchor. For highly precise control of the extrusion process, it has proven particularly advantageous to arrange the flow divider directly on the hollow bar composite anchor. In these cases, the hydraulic flows are only divided directly upstream of the extrusion rams, which enables even pressure and force distribution with simple pipe routing. The flow divider can also be arranged reversibly on the hollow bar, which represents a cost-effective, reusable solution for the use of the divider. This then makes the flow divider part of the anchor drilling and setting rig. Alternatively, the flow divider can be integrated into the hollow bar, for example, directly upstream of the extrusion rams, in which case it becomes part of the anchor. This allows for reliable distribution of the main flow to the currently existing compartmentalization.In a further embodiment of the system, the hydraulic flow divider can be arranged via an internal thread on the anchor head of the hollow bar composite anchor. For pressure-tight installation and to reduce the required supply line lengths, it has proven particularly suitable to arrange the flow divider on the hollow bar for the extrusion process. The flow divider can be applied to the anchor head at the borehole wall in a force-locking or form-locking manner, with the flow divider conveniently being handled as part of the anchor setting carriage of the drilling rig or the pressure generation system. This means that several composite anchors of the same type can be set with just one flow divider. The screwed or clamped flow divider also engages the individual compartments of the adhesive cartridge with its outlets in a pressure-tight manner.This allows the different pressure of the flow divider to be maintained in the individual components through the compartment walls after the initial movement of the respective stamps within the individual compartments to extrude the adhesive.

[0019] In a further preferred embodiment of the system, the hydraulic flow divider can have sealing surfaces, wherein the sealing surfaces are configured to hydraulically seal the individual compartment cross-sections of the adhesive cartridge during the dispensing process. To ensure uniform hydraulic pressure during the dispensing process, it has proven advantageous for a sealing connection to the individual compartments to be established via the attached mechanical flow divider. Such sealing can be achieved, for example, via the outlets of the flow divider, which contact the compartments and allow sealing through the contact surfaces, so that the pressure at the outlet of the flow divider constantly acts only on the plunger within the respective compartment during the dispensing process.Optionally, the outlets of the flow divider can also be designed so that they are pushed into the compartments during extrusion, mechanically stabilizing the extruded sections of the compartments. The sealing surfaces can, in particular, be designed to seal the respective compartments and also seal the adhesive cartridge against the hollow bar composite anchor.

[0020] In a preferred embodiment of the system, the extrusion punches can have a longest axial and a longest radial extent relative to the orientation of the hollow rod, wherein a ratio of the longest axial to radial extent, calculated from the longest axial extent of the extrusion punch divided by the longest radial extent of the extrusion punch, is greater than or equal to 2 and less than or equal to 10. The radial area of ​​the individual extrusion punches does not occupy the entire internal cross-section of the hollow rod, but is adapted to the radial cross-sectional area of ​​the corresponding compartments of the adhesive cartridge located towards the anchor base. To ensure a reproducible and stable extrusion process, it has proven particularly advantageous to maintain the relationship between radial and axial extent specified above for each punch and for the sum of the punches.The punches are therefore at least twice as long (axial direction) as they are wide (radial direction). This can contribute to particularly stable guidance of the individual punches during the setting process. More preferably, the ratio can be greater than or equal to 3 and less than or equal to 9, and further preferably greater than or equal to 4 and less than or equal to 8.5.

[0021] In a further preferred embodiment of the system, the adhesive cartridge can have two compartments. The use of a 2-component system, wherein the two components of the adhesive are each present in an independent compartment, can be ejected particularly reproducibly using the system according to the invention, even under difficult conditions, such as significantly different volumes of hardener and binder. A particular advantage of the system according to the invention using a 2-component adhesive can also be that significantly different adhesive volumes of hardener and binder can be used. Significantly different adhesive volumes are difficult to apply with conventional methods, since fluctuations in the ejection process affect the individual components significantly differently in terms of percentage.The minor component will exhibit increasingly higher percentage deviations compared to the main component when there are fluctuations in the extrusion pressure. Two-component adhesives can preferably be used with the system according to the invention, which have a volume ratio of hardener to binder, or vice versa, of greater than or equal to 1:1, preferably greater than or equal to 1:2; preferably greater than or equal to 1:3, more preferably greater than or equal to 1:4, and still more preferably greater than or equal to 1:5. Separate extrusion allows even highly asymmetrical adhesive volume ratios to be processed reliably.

[0022] In a preferred embodiment of the system, the adhesive cartridge can have an inner compartment and an outer compartment, wherein the inner compartment is configured in the shape of a cylinder, the central axis of the inner compartment coinciding with a central axis of the hollow rod, and the outer compartment is configured in the shape of a cylinder jacket and arranged around the inner compartment, the central axis of the cylinder jacket of the outer compartment coinciding with the central axis of the inner compartment. The flow dividers usable according to the invention also allow the use of adhesive arrangement geometries that cannot be used at all or only very unreproducibly with a non-selective hydraulic main flow.In this embodiment, one component is located in the center of the adhesive cartridge, while the other component is arranged around it up to the inner wall of the hollow rod in the adhesive cartridge. This division can improve the mixing result of both components and lead to a uniformly symmetrical bond around the hollow rod. This embodiment can be more suitable than a halving of the entire compartment volume, since the desired symmetry of a uniform radial distribution of the adhesive around the entire hollow rod is not achieved when ejecting from the latter. Within a further preferred embodiment of the system, the inner compartment can be mechanically fastened at one or more points to an inner circumference of the hollow rod by webs, wherein the webs are designed to be removed by arranging the hydraulic flow divider on or in the hollow bar composite anchor.To ensure secure contact with the inner compartment through the flow divider outlets, it has proven particularly advantageous for the inner compartment to be mechanically connected to the hollow bar composite anchor at one or more points, preferably in the direction of the anchor head. This can be achieved, for example, using thin webs that mechanically fix the position of the inner compartment during storage. To ensure that the webs do not hinder the ejection of the adhesive from the outer compartment, they can be removed during the connection process to the flow divider. The webs can have one or more break points for this purpose. The webs are then preferably broken through when the flow divider is arranged and accommodated by the flow divider in such a way that they cannot enter one of the compartments during the ejection process.This embodiment can contribute to a stable storage solution even when using very low-viscosity adhesive components, since the latter can stabilize the position of the inner compartment to a lesser extent than high-viscosity components.

[0023] In a further preferred embodiment of the system, the inner compartment and the outer compartment can each be filled with a different adhesive component, with the adhesive component with the lower density or higher viscosity being arranged in the inner compartment and the adhesive component with the higher density or lower viscosity being arranged in the outer compartment. This arrangement of the two adhesive components in a specifically designed, two-part adhesive cartridge can effectively stabilize the position of the inner compartment. This can help prevent the inner compartment from being secured in its position within the anchor by additional mechanical means. Furthermore, the outer compartment has a larger surface area.The larger surface area can result in lower pressure being applied when ejecting a more viscous component compared to ejecting from a compartment with a smaller surface area. In the case of different viscosities, it can be advantageous to place the higher-viscosity component in the inner compartment, as the smaller compartment surface area reduces friction for ejection compared to the outer compartment. This can keep the overall force required to eject the components lower.

[0024] In a preferred embodiment of the system, the inner compartment can have mechanical means, wherein the mechanical means are designed to fix the position of the inner compartment in the outer compartment. To ensure a storage-stable position of the inner compartment, it can be advantageous for the inner compartment to be mechanically connected to the outer compartment at one or more points on its outside. However, it is also possible for the inner compartment to have a thin tube or a thin web that extends through the inner compartment. These mechanical means can be pushed together during the extrusion process and collected, for example, upstream of the static mixer.

[0025] In a preferred embodiment of the system, the adhesive cartridge can have four compartments. The system according to the invention allows even difficult ejection geometries with multiple compartments and, if necessary, significantly different volumes of the individual compartments to be reliably managed.

[0026] In a preferred embodiment of the system, three compartments can be arranged spaced apart from one another on an inner circumference of the adhesive cartridge. The proposed system also allows for adhesive arrangements within the adhesive cartridge that would not lead to suitable anchoring results with uniform pressure application across the entire cross-sectional area of ​​the hollow rod. In particular, the almost exclusive arrangement of one component on the inner circumference of the adhesive cartridge leads to undesirable extrusion artifacts and uneven anchoring of the hollow rod in the rock with uniform pressure application across the entire cross-section. Controllable extrusion of compartments arranged on the inner circumference of the adhesive cartridge allows for significantly better and reproducible results, which is achieved through improved, separate application of force to these areas.Typically, these areas have a small radial cross-sectional area compared to the entire hollow bar cross-section, which makes uniform extrusion using state-of-the-art systems challenging.

[0027] In a preferred embodiment of the system, the three compartments arranged on the inner circumference of the adhesive cartridge can be evenly spaced from one another. To achieve the most uniform fastening result possible, it has proven advantageous to divide one of the components into three compartments, with each compartment being arranged equally spaced from one another on the inner circumference of the adhesive cartridge. The individual compartments can, for example, be arranged offset by an angle of 120° on the inner circumference of the adhesive cartridge. These compartments can preferably together occupy a volume which, in relation to the other component, is less than or equal to 1, more preferably less than or equal to 2, and further preferably less than or equal to 3.This means that even very asymmetrical adhesive volumes can be ejected, whereby in the case of a 2-component adhesive the ratio of the volumes is 1:3 in the extreme case, i.e. one of the components has a three times higher ejected volume.

[0028] In a further preferred embodiment of the system, the walls of the adhesive cartridge can be made of metal, coated plastics, or combinations thereof. To ensure the most constant and specific extrusion pressure per compartment, it has proven particularly suitable for the compartment walls to be made of metals such as steel, aluminum, or their alloys. Furthermore, high-strength plastics can also be used, which can be coated with metal, for example, to prevent the diffusion of an adhesive component during storage. Metallization of the plastic compartment interior walls can thus be useful for reducing or preventing adhesive diffusion.

[0029] In a further preferred embodiment of the system, either the hydraulic pressure generation system, the hydraulic flow divider, or the hollow bar composite anchor itself comprises means that enable a controlled discharge of the hydraulic pressure generation medium after the adhesive has been extruded and the hollow bar composite anchor has thus been set into the rock. Thus, either all of the above-mentioned components or just one or two of these components can be configured to withdraw the pressurized extrusion medium and prevent the medium from accidentally escaping into the anchor environment. This can be particularly advantageous in cases where water is used as the pressure generation medium and the environment cannot tolerate large water loads.This design is particularly suitable for salt mining, where uncontrolled water discharge from the anchor after the setting process can lead to highly detrimental results in the form of brine formation. The extraction of the extruded fluid can be achieved by retracting the extruding pistons or by maintaining the piston position after extruding. For example, the fluid can be extracted or drained from the pipes and the anchor via a valve using a hydraulic device. It is also conceivable for the extruded fluid to be extracted via a vacuum device. The extruded fluid can therefore be reused in subsequent setting processes, which improves the sustainability of the system and conserves environmental resources.A further advantage of this additional device for withdrawing the extruded medium can be seen in the fact that the controlled withdrawal of the medium after extrusion is very gentle and controlled on the technical environment. Strong pressure drops are avoided, which increases the longevity of the devices and the system. Furthermore, the use of the system according to the invention for stabilizing rock layers in mining, tunneling, civil engineering, and rock construction is also in accordance with the invention. Surprisingly, it has been shown that difficult-to-stabilize rock layers can be secured very reproducibly using the system according to the invention. A variety of 2- or multi-component adhesive systems can be used, which produce unsatisfactory results with only one pressure application.In addition, adhesive systems with significantly different hardener and binder volumes can be used, which would produce unsatisfactory results if only a single, uniform dispensing of the adhesive. Thus, the system according to the invention can also handle difficult bonding situations, such as those encountered in rock construction.

[0030] Further advantages and advantageous embodiments of the inventive objects are illustrated by the drawings and explained in the following description. It should be noted that the drawings are for descriptive purposes only and are not intended to limit the invention in any way.

[0031] The figures show:

[0032] Fig. 1 shows schematically the structure of a system according to the invention;

[0033] Fig. 2 shows schematically a hollow bar composite anchor suitable for use in the system according to the invention with direct connection of a hydraulic flow divider;

[0034] Fig. 3 shows schematically a possible design of the compartment division of an adhesive cartridge in plan view;

[0035] Fig. 4 shows a schematic view of another possible embodiment of the compartmentalization of an adhesive cartridge in plan view; Fig. 5 shows a schematic view of another possible embodiment of the compartmentalization of an adhesive cartridge in plan view;

[0036] Fig. 6 shows schematically another possible embodiment of the compartment division of an adhesive cartridge in plan view;

[0037] Fig. 7 shows schematically another possible embodiment of the compartment division of an adhesive cartridge in plan view;

[0038] Fig. 8 shows a schematic diagram of the division of three independently operating extrusion dies in plan view.

[0039] Figure 1 schematically shows the structure of a system according to the invention. The system comprises, as individual components, a hydraulic pressure generation system 2, a hydraulic flow divider 3, and a hollow bar composite anchor 1. The hydraulic pressure generation system 2 generates the necessary hydraulic pressure to extrude the adhesive and thus to insert the hollow bar composite anchor 1 into the rock. The hydraulic pressure generation system 2 can be designed in the form of a pump. Water is preferably used as the hydraulic medium. The hydraulic flow divider 3 can be arranged directly on the hydraulic pressure generation system 2, between the hydraulic pressure generation system 2 and the hollow bar composite anchor 1, or directly on the hollow bar composite anchor 1.The output of the hydraulic pressure generation system 2 forms the input of the hydraulic flow divider 3, which divides the input flow into two or more output flows, possibly with different pressure levels, according to the requirements of the hollow bar composite anchor 1. The output flows from the hydraulic flow divider 3 are then forwarded separately to the hollow bar composite anchor 1 via separate lines. These lines can be omitted if the hydraulic flow divider 3 is arranged directly on the hollow bar composite anchor 1. The hydraulic flow divider 3 divides the water pressure supplied by the hydraulic pressure generation system 2 into different water pressures according to the requirements of the adhesive system in the hollow bar composite anchor 1.The different water pressures can cause different forces and thus different extrusion speeds on the extrusion rams 12 during the extrusion process of the hollow bar composite anchor 1. Alternatively, the goal can also be to generate exactly the same extrusion speeds for each ram. In this case, the mixing ratios of the adhesives can, in principle, be precisely controlled by the size of the respective compartments and / or the flow velocities from the individual compartments.

[0040] Figure 2 shows a schematic view of a hollow bar composite anchor 1 suitable for use in the system according to the invention. The hollow bar composite anchor 1 is inserted through the borehole mouth 4 into the already drilled hole in a rock layer. The anchor base 5 is located furthest from the borehole and generally has several outlet channels 6 through which the mixed adhesive system is pressed from the hollow bar composite anchor 1 into the surrounding rock, thus bonding the hollow bar composite anchor 1 to the rock. In the order from the borehole mouth 4 or anchor head 16 to the borehole mouth 4 or anchor head 16, the hollow bar composite anchor 1 has a static mixing device 8 and an adhesive cartridge 9 located inside the hollow bar 7. By applying a mechanical force, the ejection piston 11 is moved through the hollow bar 7 and acts on the adhesive cartridge 9, which is located inside the hollow bar 7.This figure shows that the dispensing piston 11 has already moved through the adhesive cartridge 9 and has conveyed a large portion of the adhesive towards the static mixing device 8. The dispensing piston 11 consists of several dispensing rams 12, which can move independently of one another in the hollow bar 7 without being mechanically coupled. The mechanical force for moving the dispensing piston 11 is provided by a hydraulic flow divider 3 arranged on the hollow bar composite anchor 1, which divides an input flow generated by a hydraulic pressure generation system 2 (not shown) into several output flows. The hydraulic flow divider 3 does not necessarily have to be arranged directly on the hollow bar composite anchor 1. It is also possible for the hydraulic flow divider 3 to be arranged in the line path between the hollow bar composite anchor 1 and the hydraulic pressure generation system 2.The hydraulic flow divider 3 can alternatively be arranged in the hydraulic pressure generation system 2 itself and transmit the different pressures via separate lines. The output flows generated by the hydraulic flow divider 3 have different pressure levels and are each directed to a respective extrusion ram 12 of the extrusion piston 11. Thus, via the settings of the hydraulic flow divider 3, each extrusion ram 12 of the extrusion piston 11 can be moved independently of one another. Due to the mechanical decoupling of the extrusion rams 12, they can move at different speeds within the hollow bar composite anchor 1 and expel the different components of the adhesive system at different speeds. This allows the use of a variety of multi-component systems. This applies particularly to adhesive systems that have significantly different volumes for the individual components.By precisely and individually controlling the ejection of the individual components, significantly more reproducible results can be achieved in the setting process. Alternatively, improved, i.e., highly uniform punch speeds for the individual extrusion punches 12 can be achieved.

[0041] Figure 3 shows a schematic view of a possible compartment division of an adhesive cartridge 9. The adhesive cartridge 9 is shown in the direction of view from the borehole mouth 4 towards the anchor base 5. The adhesive cartridge 9 is divided into two different compartments 10, each compartment 10 containing a different adhesive component. In this case, a 2K adhesive can be used. The compartment cross-section 13 is semicircular for both components. Figure 4 shows a schematic view of a possible compartment division of an adhesive cartridge 9. The adhesive cartridge 9 is shown in the direction of view from the borehole mouth 4 towards the anchor base 5. In this case, a 2K system is also used to set the hollow bar composite anchor 1. One of the components is arranged in an inner compartment 14 and the other component around it in an outer compartment 15.The outer compartment 15 is designed in the shape of a cylindrical shell and arranged around the inner compartment 14. The central axis of the cylindrical shell of the outer compartment 15 coincides with the central axis of the inner compartment 14. The inner compartment 14 has a round compartment cross-section 13. The purpose of this arrangement is to ensure that the flow divider 2, regardless of whether it is pressed or turned open, always sits precisely positioned with its inlet nozzles on or in the respective compartments 14 in front of the respective extrusion rams 12.

[0042] Figure 5 schematically shows a possible compartmentalization design of an adhesive cartridge 9 in a top view. The adhesive cartridge 9 is shown looking from the borehole mouth 4 toward the anchor base 5. The cross-sectional distribution in this design is asymmetrical, with the individual components of the 2K system occupying significantly different volumes.

[0043] Figure 6 shows a schematic view of a possible compartment division of an adhesive cartridge 9. The adhesive cartridge 9 is shown in the direction of view from the borehole mouth 4 towards the anchor base 5. The division of the cross-sections is asymmetrical in this design, with the individual components of the 2-component system occupying significantly different volumes. To even out the mixing result, one component is divided into two compartments located at the edge of the hollow bar composite anchor 1. Figure 7 shows a schematic view of a possible compartment division of an adhesive cartridge 9. The adhesive cartridge 9 is shown in the direction of view from the borehole mouth 4 towards the anchor base 5. The division of the cross-sections is symmetrical in this design, with the individual components of the 2- or more-component system occupying significantly different volumes.The adhesive cartridge 9 has four compartments 10, with three compartments 10 arranged at a distance from one another on an inner circumference of the adhesive cartridge 9. In this embodiment, the three compartments 10 arranged on the inner circumference of the adhesive cartridge 9 are evenly spaced from one another. Figure 8 shows a possible division of the extrusion dies 12 for a compartment division illustrated in Figure 7. There are four independently movable extrusion dies 12, each of which can act with its cross-section on only one compartment 10 of the adhesive cartridge 9. The individual extrusion dies 12 of the extrusion piston 11 can move at different speeds and dispense the volume of the respective compartment 10 of the adhesive cartridge 9 at different speeds.

[0044] The latter is achieved by using a hydraulic flow divider 3, which can generate a suitable hydraulic pressure tailored to the respective extrusion ram 12.

[0045] Reference symbol

[0046] 1 hollow bar composite anchor

[0047] 2 hydraulic pressure generation unit

[0048] 3 hydraulic flow divider

[0049] 4 Borehole mouth

[0050] 5 Anchor foot

[0051] 6 outlet channels

[0052] 7 hollow rod

[0053] 8 static mixing device

[0054] 9 adhesive cartridges

[0055] 10 compartments

[0056] 11 squeezing pistons

[0057] 12 pressing stamps

[0058] 13 Compartment cross-section

[0059] 14 inner compartment

[0060] 15 outer compartment

[0061] 16 Anchor head

Claims

Patent claims 1. A system for setting a hollow bar composite anchor (1) in rock strata, comprising at least one hydraulic pressure generating unit (2) and a hollow bar composite anchor (1) hydraulically connectable to the hydraulic pressure generating unit (2), wherein the hollow bar composite anchor (1) has an anchor base (5) with one or more outlet channels (6), a hollow bar (7) arranged on the anchor base (5) and containing a static mixing device (8), an adhesive cartridge (9) with several compartments (10), and an extrusion piston (11), characterized in that the extrusion piston (11) is formed in several parts in an axial direction corresponding to the number of compartments (10) of the adhesive cartridge (9) and has extrusion punches (12) that are independently displaceable in the hollow bar (7) in the axial direction and each adapted in a radial cross-sectional area to a compartment cross-section (13) of the adhesive cartridge (9),wherein a hydraulic flow divider (3) is arranged between the hydraulic pressure generating unit (2) and the extrusion piston (11), wherein the hydraulic flow divider (3) is designed to exert different hydraulic forces on each extrusion piston (12) independently of one another.

2. System according to claim 1, wherein the hydraulic flow divider (3) can be arranged on or in the hollow bar composite anchor (1).

3. System according to claim 2, wherein the hydraulic flow divider (3) can be arranged via an internal thread on the anchor head (16) of the hollow bar composite anchor (1).

4. System according to one of the preceding claims, wherein the hydraulic flow divider (3) has sealing surfaces, wherein the sealing surfaces are designed to hydraulically seal the individual compartment cross-sections (13) of the adhesive cartridge (9) during the squeezing process.

5. System according to one of the preceding claims, wherein the extrusion dies (12) have a longest axial and a longest radial extent relative to the orientation of the hollow rod (7), wherein a ratio of the longest axial to radial extent, calculated from the longest axial extent of the extrusion die (12) divided by the longest radial extent of the extrusion die (12), is greater than or equal to 2 and less than or equal to 10.

6. System according to one of the preceding claims, wherein the adhesive cartridge (9) has two compartments (10).

7. System according to claim 6, wherein the adhesive cartridge (9) has an inner compartment (14) and an outer compartment (15), wherein the inner compartment (14) is designed in the shape of a cylinder, wherein the cylinder center axis of the inner compartment (14) coincides with a center axis of the hollow rod (7) and wherein the outer compartment (15) is designed in the shape of a cylinder jacket and is arranged around the inner compartment (14), wherein a center axis of the cylinder jacket of the outer compartment (15) coincides with the center axis of the inner compartment (14).

8. System according to claim 7, wherein the inner compartment (14) is mechanically fastened at one or more locations by webs to an inner circumference of the hollow bar (7), the webs being adapted to be removed by arranging the hydraulic flow divider (3) on or in the hollow bar composite anchor (1).

9. System according to claim 7 or 8, wherein the inner compartment (14) and the outer compartment (15) are each filled with a different adhesive component, wherein the adhesive component with the lower density and / or the higher viscosity is in the inner compartment (14) and the adhesive component with the higher density and / or the lower viscosity is arranged in the outer compartment (15).

10. System according to one of claims 7 to 9, wherein the inner compartment (14) has mechanical means, the mechanical means being adapted to fix the position of the inner compartment (14) in the outer compartment (15).

11. System according to one of claims 1 to 5, wherein the adhesive cartridge (9) has four compartments (10).

12. System according to claim 11, wherein three compartments (10) are arranged spaced apart from one another on an inner circumference of the adhesive cartridge (9).

13. System according to claim 12, wherein the three compartments (10) arranged on the inner circumference of the adhesive cartridge (9) are evenly spaced from one another.

14. System according to one of the preceding claims, wherein the walls of the adhesive cartridge (9) consist of metal, coated plastics or combinations thereof.

15. Use of a system according to one of claims 1 to 14 for securing rock layers in mining, tunnelling, civil engineering and rock construction.

Images