EP1805395B1 - Method for embedding rock anchors - Google Patents

Abstract

A hardening mass is comprised of a mixture of hardenable plastic and hardening plastic supplied to an inner channel (8) of a drill rod (1) over a preset transport time. The plastics and the mixing ratio of the plastics are selected such that the transport time corresponds to a hardening time and the hardened mixture fills the flow path between the mixing point and output of a drilled hole of a rock.

Description

The invention relates to a method for setting rock anchors, according to the preamble of claim 1.

This method is known by the DE 102 34 255 A1 or WO 03/044324 A1 , In this method, a drilling injection anchor, which is designed as a boring bar with a central inner channel, driven into the mountains to be armed. At the same time, the rinsing is carried out with a liquid through which the borehole is widened. After reaching the intended drilling length is through the inner channel of the drill rod, the injection of a viscous cement mixture, which fills the hole and hardens to a Betonkem, in which the boring bar remains.

This method is especially intended for soft and sandy rocks. In harder rock, as it is found in particular when upgrading the track in underground mining or tunneling, mainly hardening plastics are shipped instead of concrete These hardening plastic are entered after drilling the borehole and pulling out the drill rod by a lance into the hole; then the lance is pulled out of the hole and a rock bolt driven into the well, which is then connected by the hardening plastic with the surrounding rock solid and sustainable.

It is an object of the invention to provide a method in which in an uninterrupted operation an anchor rod, which may also be the boring bar, set as rock anchors by filling the borehole with a thermosetting plastic, thereby ensuring that on the one hand the borehole On the other hand, despite the usual over-head working, no plastic escapes from the borehole in substantial quantities over its entire length.

The solution results from claim 1. It takes into account the fact that curing plastics in a low curing time lead to a much higher hardness or viscosity than a cement injection. On the other hand, it is avoided that the thermosetting plastic leads to contamination of the drill and the environment and wasted in uneconomical ways larger amounts of this plastic become.

To such a cure is used as hardness components z. B. a radical polymerization of unsaturated polyester resins, vinyl esters, epoxy acrylates, silicate resins, e.g. by adding peroxides in a volumetric ratio of 1: 1 to 10: 1 applied.

Suitable hardening plastics and hardening plastics are eg in the DE 103 15 610 B4 . DE 101 24 466 C1 . DE 102 18 718 C1 described.

An essential advantage of the invention is that it permits the substantially automatic filling of the borehole, wherein the borehole is substantially completely filled from the tip of the boring bar or rock bolt to the mouth of the borehole and the boring bar or rock bolt is completely filled with the borehole hardened plastic is sheathed. This is sufficient for a substantial safety requirement of mining and tunneling.

One of the essential criteria of the invention is that the delivery time F and the curing time H are matched to one another. The curing time H of the plastic is determined by the choice of the hardenable plastic and the hardening plastic and optionally other components and by the mixing ratio of the components, but also by the temperature of the environment, the quantitative main components and the rock.

The delivery time F is given as the time required to completely backfill the flow path of the cure mixture. That is, the curing of the thermosetting plastic takes place only after mixing with the curable and the curing plastic. The flow path is therefore the distance between the mixing point and the mouth (outlet) of the borehole. If the mixture of the two components is carried out by a static mixer, the mixing point is at this static mixer. The flow path then includes the further inner channel up to its exit on the outer circumference of the drill, generally up to the drill bit. The flow path further comprises the drill hole surrounding the anchor rod. The delivery time is therefore such that, taking into account the delivery characteristics of the pumps, in particular the pressure dependence of the delivery characteristics sufficient, and the volume of the inner channel and the volume of the anchor rod surrounding wellbore fills.

The invention can be carried out by first drilled a hole with a conventional drill rod and then pulled back the boring bar out of the hole and instead a tubular anchor rod (= rock anchor) is introduced with an inner channel. This method has, in addition to the other advantages, the advantage that the drill bit to be used for hard rock, which is expensive, can be used several times.

However, it is also possible to drill the hole with an inner channel boring bar, which is also designed as a suitable anchor rod. This Borhrstange remains in the borehole and is used according to the invention after drilling as rock anchors. The disadvantage of using only once is the technical advantage over that time-consuming steps omitted.

In the context of this application, in particular the use of the drill rod is described as rock anchors; However, the invention also applies and the method is used identically for a method in which - as described - not the boring bar but a subsequently introduced anchor rod is used with inner channel.

Claim 2 ensures that the hardening mixture does not form any cavities in the borehole and comes into intimate contact with the wall of the boring bar and the wall of the borehole. This measure can be done in addition to the usual during drilling water flushing of the borehole and has the advantage that even water residues are blown out of the well and dried.

It should be noted that the drill rod may be provided at its tip with a drill bit, the cutting blades bypass a hole diameter which is greater than the outer diameter of the drill rod.

The curing of the curable plastic component means an increase in viscosity beyond the viscous and pasty area. The aim is a viscosity of the curable component of at least 100,000 pa x sec, so that the compound of the plastic mass against the borehole and against the boring bar is so strong that the Borehole at the usual operational loads associated with the drilling operation and the injection of the plastic mass, can no longer be pulled out of the well or rotated in the borehole. It is thus possible, the drill chuck, in which the boring bar is clamped for the purpose of drilling, and / or the injection head (adapter for connecting the plastic leads to the inner channel of the anchor rod / boring bar) without the aid of a holding the boring bar holding device, retaining claw of the Loosen the drill rod, z. B. by backward rotation of the drill chuck (claim 5 and 6).

In an advantageous embodiment according to claim 7, it is provided that the plastics after merging and mixing in a very rapid chemical reaction to a - so called here - pasty mass crosslink. This is done by admixing suitable substances, e.g. Amines. In the method according to claim 8, the handling is facilitated and the reliability increased by the fact that after the merging and mixing of the components and before the onset of leading to curing chemical reaction increased viscosity (greater than 500 pa sec, preferably greater than 1000 pa sec) is reached. This pre-reaction is caused by mixing in a small amount of substances with suitable tixotropic properties, e.g. Substances from the group of amines.

By this initially only small, but very rapid increase in viscosity before the onset of finally desired curing (tixotropic effect) is achieved that the hardening mixture of plastics does not flow out of the well without allowing the pressure build-up, which is required to the hole as a whole and complete with all cavities completely and completely.

To further reduce the drilling and injection process, the development according to claim 8 is used. This prevents that not fully cured plastic material from the inner channel of the drill rod expires after the release of the drill chuck or after loosening the plastic feed channel or dripping or swelled out.

When calculating the delivery time and adjusting the hardening time, the pumping characteristics of the pumps through which the hardenable material must flow must be determined Component and the curing component is supplied to the inner channel of the boring bar, to be considered.

Ideally, pumps are selected whose delivery rate per unit time is not dependent on the backpressure. In this respect, in particular piston pumps and of these in particular radial piston pumps are suitable.

This is particularly useful because it prevents a temperature increase of the plastics, which could lead to a change in the Aushärtcharakteristik and in particular to a shortening of the curing time.

In order to prevent liquid shocks and thus the bursting of lines i should be provided in the development of the method that the pumps can start with a delay. Also shortly before the end of the delivery time is a reduction of the delivery speed to avoid pressure peaks appropriate.

Alternatively, it is also possible to use pumps with a pressure-dependent delivery characteristic to convey the curable plastic and / or the hardening plastic. Such pumps, e.g. Gear pumps have the advantage of their simple design. Incidentally, the pressure-dependent delivery characteristic has the advantage that pressure peaks are avoided. On the other hand, the pressure dependence in the case of the internal reflux of the excess flow rates also leads to heating; Therefore, the Aushärtcharakteristik and in particular the curing time must be adjusted accordingly.

In the development of the invention according to claim 11, a shutdown of the supply of curable and / or curing plastic, if the respective discharge pressure exceeds a predetermined limit. But it can also be an outlet program of the drive motors of the pump are turned on, by which the speeds of the pumps are returned continuously or in stages to zero. As a result, damage to the conveyor system and possible contamination by one of the plastic components are avoided.

If, in this case, the pressure increase is due to curing of the plastic prior to complete filling of the borehole, however, a new boring is to be carried out and the boring bar may be lost. In this case, however, there is a poor coordination of filling time and curing time. If the filling time and the hardening time are precisely matched, this pressure-dependent shutdown occurs as precisely as possible at or shortly before the time at which the plastic comes out of the borehole mouth.

However, it is also possible to specify the conveying time F by hand or by means of an adjustable clock. The aim is that the curing time and thus the filling time is less than one minute.

The vote of filling time and curing time can be done by experiment, although the delivery characteristics of the pump and the filling volume V of the inner channel and the borehole surrounding borehole is at least roughly considered. The algorithm to be followed for the coordination of filling time and curing time results from claim 11.

In order to make the advantage of the invention, namely the rapid and safe integration of a rock bolt in a borehole fully usable, the development of the method according to claim 12ff is of particular importance. Claim 12 ensures the reliable connection of the plastic leads to the inner channel of the anchor rod / drill rod and avoids unnecessary assembly and adjustment that serve this purpose. For this purpose, an injection head - referred to in this application also adapter, the one side of the plastic line, on the other hand, but also serves as a tool for connecting the inner channel of the anchor rod with the plastic pumps.

Claim 13 serves the purpose of avoiding mixing of the components at the wrong time, that is to say in particular before the intended mixing point and static mixer, and thus premature curing of the plastics and contamination of the pipe systems by cured plastics.

Also claim 14 serves a similar purpose and at the same time ensures the effective cleaning of points of the supply system to which the plastic deposit are disturbing.

In the following an embodiment of the invention will be described with reference to the drawing:

• Figur 1 schematisch eine Bohrstange mit Bohrfutter und Zufuhradaptem (Injektionskopf).
• Figur 2 ein Förderdiagramm
• Figur 3 und 4 schematisch eine Bohrstange mit Bohrfutter und Zufuhradaptern (Injektionskopf).

Show it:

• FIG. 1 schematically a drill rod with chuck and Zufuhadaptem (injection head).
• FIG. 2 a funding diagram
• FIG. 3 and 4 schematically a drill rod with chuck and Zuführadaptern (injection head).

In the figures, it is described that a drill rod remains in the wellbore that has been drilled with it and then remains in the wellbore as an anchor rod / rock bolt and is poured. Therefore, the drilling process is described to the figures. However, if the boring bar is withdrawn from the hole after completion of the borehole and an anchor rod is inserted as a rock bolt instead of it, the production of the borehole is no longer within the scope of this invention; Otherwise, however, all embodiments that describe the inventive method for filling the inner channel of the anchor rod and the Behohrlochs with a thermosetting plastic mixture (hardening mixture). The following explanations apply to all figures, unless it is expressly referred to deviations with respect to individual figures.

The drill rod 1 with a drill bit 2 is through the chuck 3 in a

Mountains 19 drilled from solid rock. For this purpose, the drill chuck 3 is driven in the direction of feed 4 and direction of rotation 5.

The drill rod consists of several - here two pieces - which can be assembled by screwing in a nut 6 to a predetermined length. For this purpose, the drill rods are provided on its outer circumference with a thread which fits into a corresponding thread of the cap nut 6. This thread also serves the purpose of allowing a good connection of the drill rod 1 with the plastic to be filled into the borehole.

The drill bit 2 is occupied with 7 clips. These drill holes 7 cover a borehole cross section with a diameter D ₁ . This diameter D ₁ is greater than the outer diameter D _{A of} the drill rod 1 and, of course, larger than the inner diameter of the thread D _I. Calculated, the volume of the drill rod with sufficient accuracy by the average diameter D ₂ = (D _A + D _I ) / 2 determined. The boring bars 1 and the sections of the boring bar are penetrated centrally by an inner channel 8, which in the drill bit 2 opens into a collecting space 9 and in exit channels 10. The inner channel can through the chuck 3 via suitable adapter first with water or air as a rinse and then preferably also on the chuck, but also on any other suitable connector, which, for example, based on Fig. 4 be loaded with a hardenable plastic compound and a hardening plastic.

Only provided for loading with plastic device parts are shown here schematically. It is the injection head / adapter 11, which can be placed on the front side of the connector, here chuck, and the inner channels 12 and 13 has. The inner channel 12 is connected via hose 27 and feed pump 14 with a reservoir 15 for a curable plastic material. The inner channel 13 is substantially smaller in its width than the inner channel 12; its cross-sectional area is about 1/10 of the cross-sectional area of the inner channel 12. The inner channel 13 is connected via tubing 25 and a feed pump 16 with a storage container 17 for the curing plastic composition. Since the curable synthetic material and the hardening plastic compound are mixed in a ratio of 10: 1 or less (up to 1: 1, see above), the delivery pump 16 is correspondingly smaller. The inner channels are brought together in the connecting piece / drill chuck 3 in a collecting chamber 18, which then corresponds to the inner channel 8 of the drill rod.

In Fig. 1 It is shown that the first segment of the drill rod at the entrance of its inner channel 8 has a static mixer 20. Such a mixer may also be at the beginning of each segment. If the static mixer is designed as an insertable component, it is sufficient if such a static mixer 20 is inserted into the inner channel 8 of the last boring bar 1 to be introduced. In the secondary figure, an insert member 21 is shown in which in addition to the static mixer 20 and a check valve / ball valve 22 is integrated. The insert member 21 may in the inner channel 8 of the last introduced boring bar before drilling z. B. be screwed with thread.

Function and operation:

For boring the boring bar 1, initially only one boring bar element is inserted into the drill chuck. The drill chuck turns in the direction of rotation 5 added. At the same time - in a manner not shown - a feed force 4 exerted on the drill rod. As a result, a borehole is introduced into the mountains with the diameter D1 of the drill bit or the cutting blades 7 on the drill bit. When the drill hole has reached the length of the first segment of the drill rod, the cap nut 6 is screwed onto the free end and screwed into this another segment of the drill rod 1, in which it - is supplied from behind through the chuck - in a manner not shown , In this case, the well can be rinsed in a manner not shown by water, which is supplied through the inner channel of the drill rod.

When the intended depth of the borehole is reached (eg at 2 m to 2.50 m) the drilling process is terminated. It is now the collection chamber 18 of the borehole - in a manner not shown - applied through the inner channel 8 of the boring bar with air and thereby rinsed the cuttings from the well and cleaned the well and dried. Subsequently, the filling of the borehole is carried out with a curable plastic, which is previously mixed with a hardening plastic. The filling volume is on the one hand, the inner channel 8 from mixer 20 and the other the borehole, ie $${\mathrm{V}}_{\mathrm{ges}}={\mathrm{V}}_{\mathrm{I}}+{\mathrm{V}}_{\mathrm{well}}-{\mathrm{V}}_{\mathrm{drill\; rod}}=\mathrm{pi}/4\left({\mathrm{L}}_{\mathrm{B}}\times \left({\mathrm{D}}_1{}^2-{\mathrm{D}}_2{}^2\right)+{\mathrm{L}}_{\mathrm{i}}\times {\mathrm{D}}_1{}^2\right)$$

The filling is carried out by the pumps 14 and 16. These are, for. B. to radial piston pumps, which can deliver a pressure-independent flow rate per unit time. However, it may also be gear pumps, since the high viscosities of the promotional plastics is not to be expected inadmissible losses and the funding law is therefore sufficiently accurately determinable.

The flow rate is set by appropriate default and speeds of the drive motors 24 and 26 of the pump now so that, taking into account the delivery characteristics and the delivery law, the filling quantity of thermosetting plastic and curing plastic is promoted exactly in those delivery time, which corresponds to the curing time.

The curing time of the plastic can be determined on the one hand by the selection of the plastic components, on the other hand also by the mixing ratio and by the temperature. The Temperature can be z. B. be assumed at 30 ° C. The hardness of the plastic in the curing time is determined by practical considerations. In particular, the plastic should not emerge by itself from the mouth of the borehole, but at best appear as pasty mass in the mouth of the borehole. It is also beneficial for the speed of the overall drilling and backfilling process when the plastic at the mouth of the wellbore has hardened to such an extent that the chuck can be separated from the drillstring without having to hold the drill rod with special tools or from falling out to prevent from the borehole. A viscosity of 100,000 pa sec. May be sufficient, but is preferably also exceeded. By suitable admixtures, a pre-crosslinking of the introduced plastic mixture with increasing the viscosity (so: more than 500 pa sec) take place before the actual curing reaction starts or has an effect.

It is desirable to separate the drill chuck from the drill rod as quickly as possible, at a time when the last registered plastic mix has not yet completed the curing time. Therefore, in the flow direction in front of the static mixer, the check valve 22 is provided which opens in the direction of backfilling and in the opposite direction prevents the registered plastic mixture to flow out of the inner channel again.

After removing the drill chuck from the drill rod, the connector / chuck can be rinsed with one of the plastic components or with water. The corresponding devices are not shown.

In Fig.2 schematically is a delivery diagram of the subsidized plastic components, ie in particular the curable plastic component and the curing plastic component and possibly the other admixed substances shown. Shown is the course of the flow rate per unit time over time and above the corresponding pressure profile in the collection chamber 18 or at another point. The delivery depends on the one hand on the speed curve of the drive motors of the pump. In addition, in some types of pumps with the Pressure dependence of the flow rate can be calculated. Ideal would be a constant delivery characteristic, as they have eg radial piston pumps. The aim is in any case, that the pumps start in a steady state, to avoid pressure surges.

The inventive method can therefore also be carried out when the curable and the curing plastic during the delivery time F with a variable flow rate according to predetermined course of delivery per unit time, in particular with delayed increasing flow rate are promoted at the beginning of the funding period or if the curable and the curing Plastic are promoted during the delivery time F with a pressure-dependent according to a predetermined law flow rate per unit time. In any case

If, after reaching the maximum set speed, the flow rate per unit time decreases with the increasing pressure, which results from the fact that on the one hand, the flow path of the plastic mixture is longer and on the other hand, the viscosity increases, the total delivery time is calculated so that the capacity in this Delivery time - in the diagram is the shaded area below the flow rates - curve - the volume of the inner channel and borehole - as described above - corresponds and that this conveying time corresponds to the curing time. This ensures that the arriving at the borehole mouth plastic mouth has become so highly viscous that it shuts off the mouth and the Bohranker so tightly encloses that he can withstand the torque created when loosening the chuck and that he does not fall out of the well under its own weight ,

Under this condition, it is possible to operate the controller 28 by hand or by presetting an operating time for the pump motors. However, it is also possible to provide control by the pressure sensor 23, through which the shutdown or, as shown, a discharge circuit takes place when the pressure before the mixing device - e.g. in the collection chamber - exceeds a preset limit G to be determined by trial.

Figure 3 distinguished by the following:

The chuck is removed after completion of the well. The connection of the anchor rod / boring bar 1 with the injection head / adapter 11 is effected by a connector 3. This consists - as the minor figure too Fig. 4 shows, from two half-shells 31, 32. These have on their length in each case a semicircular recess 33,34. These recesses complement each other in the closed state of the half shells in the arrow direction to a circular cylindrical inner channel with changing diameters. The diameters are designed so that the inner channel in the closed state - like Figure 4 shows - a positive fixing of the connector on one side causes the injection head 11 and on the other side of the anchor rod / boring bar 1. The injection head therefore has a bead 35, which fits into a corresponding diameter extension of the inner channel 33,34. For holding the anchor rod / boring bar 1, the inner channel has a coarse internal thread, which corresponds to the external thread of the anchor rod / boring bar 1.

In Figure 3 It is shown that the gap 18 between the end of the injection head 11 and the end of the anchor rod / drill rod 1 is bridged by means of an annular seal 30 and radially sealed. The static mixer 20 is also here at the beginning of the anchor rod / drill rod 1. In the execution of Figure 4 in contrast, the static mixer is in the connecting piece 3 with the half-shells 31,32. For this purpose, the mixing elements 20 are also here in an insert component / mixer housing 21, which is designed as a circular cylindrical tube. Externally, this tube has at its beginning a bead 36, which in the closed state in the arrow direction of the half-shells 31,32 by an entsrechenden recess of the inner channel of the half-shells 31,32 positively enclosed and axially and radially fixed. In addition, the inner channel of the half-shells 31,32 encloses the tube of the mixer housing tight fitting.

This is particularly important because preferably the mixer housing 21 is made of plastic and only by the tight contact with the walls of the firmly pressed half shells is sufficiently pressure resistant.

Furthermore, it is particularly important that the mixer housing is also positively supported at its outflow end in the axial direction in order to prevent that a mixer housing made of plastic ruptures or tears axially. This axial fixing is done in the example shown by support on the end face of the facing end of the anchor rod / drill rod 1, which in turn - as stated - is fixed in the half-shells of the connector. That too Fig. 1 and 3 illustrated and described check valve is not shown here, but would also be used here with corresponding advantage.

After completion of the filling time and completion of the filling of the borehole, the half-shells are moved apart (against the arrow direction), so that the anchor rod / drill rod and the injection head are released. In this case, the static mixer, which - as described - is designed as a unit - be ejected because it is still filled with the thermosetting plastic mixture. If necessary, the injection head and / or connector 3 are cleaned and then a new assembly inserted as a mixer before the attachment to another anchor rod / drill rod and their filling begins.

In the method according to Figure 4 an extended type of control is also used. There is an activation and deactivation of the system for filling a borehole by switch 29, which synchronously the two check valves 38 and 39 in the inner channels 12,13 of the injection head 11 in terms of flow or in the sense of pressure-safe Blocking actuated To start the filling, the two pumps 24, 26 are first put into operation by means of control 28. After pressure build-up in the supply lines 25,26 the check valves 38,39 are opened in synchronism with each other by means of switch 29, so that the mixing and filling process begins immediately with the presence of both components. After expiration of the operating time / curing time - as described above - the switch 29 is again actuated in the sense of synchronous and abrupt blocking of the check valves 38,39. It is thereby ensured that after blocking on the exit surface 37 on the mixer 20 facing end face none of the components more leak and can lead to contamination. In addition, however, it is provided that the exit surface is cleaned after opening the half-shells 31,32 with a pressurized water jet. In any case, the exit surface is 37 even and without projections or depressions designed so that it can be easily and effectively cleaned.

When the check valves are locked, the two pumps in the lines 25,27 build a higher pressure. By pressure sensor 23 in each of the lines of this pressure is queried and fed via lines 40, 41 of the controller 28. In the control device is stored, which limit pressure may be stored in the one and the other line maximum. If one of these limit pressures is reached, the shutdown of the affected pump drive, preferably both pump drives / motors 24,26 done by the control device.

The execution after Figure 4 also has the peculiarity of the method that the two plastic components or their leads 12,13 are combined in the injection head Y-shaped or T_förmig in a point which lies just before or best in the exit surface 37. Especially the latter case facilitates the cleanliness or cleaning of the exit surface.

reference numeral

1.

Bohrstange, Ankerstange 1

2.

Bohrkrone 2

3.

Bohrfutter 3, Verbindungsstück

4.

Vorschubrichtung 4

5.

Drehrichtung 5

6.

Mutter 6 Überwurfmutter 6

7.

Kluppen 7 Bohrkluppen 7

8.

Innenkanal Zentralkanal 8

9.

Sammelraum 9

10.

Austrittskanälen 10

11.

Adapter 11, Injektionskopf

12.

Innenkanal 12

13.

Innenkanal 13

14.

Förderpumpe 14

15.

Vorratsbehälter 15 für eine aushärtbare Kunststoffmasse

16.

Förderpumpe 16

17.

Vorratbehälter 17 für die härtende Kunststoffmasse

18.

Sammelkanal 18, Zwischenraum

19.

Gebirge 19

20.

statischen Mischer 20, Mischelemente

21.

Einsatzbauteil 21 Mischergehäuse

22.

Rückschlagventil/Kugelventil 22

23.

Druckfühler 23

24.

Motor 24, Pumpenantrieb

25.

Schlauch 25, Leitung

26.

Motor 26, Pumpenantrieb

27.

Schlauch 27, Leitung

28.

Steuereinrichtung 28, Steuerung

29.

Ein/Ausschalter, Schalter 29

30.

Dichtring, Dichtung

31.

Halbschale 31

32.

Halbschale 32

33.

Ausnehmung 33

34.

Ausnehmung 34

35.

Wulst 35

36.

Wulst 36

37.

Stirnfläche, Austrittsfläche 37

38.

Sperrventil 38, elektromagnetisch

39.

Sperrventil 39, elektromagnetisch

40.

Leitung 40

41.

Leitung 41

Bohrlochquerschnitt mit einem Durchmesser D₁.
Außendurchmesser D_A der Bohrstange 1
Innendurchmesser des Gewindes D_i
mittleren Durchmesser D2 = (D_A + D_i)/2

1.

Boring bar, anchor rod 1

Second

Drill bit 2

Third

Drill chuck 3, connector

4th

Feed direction 4

5th

Direction of rotation 5

6th

Nut 6 union nut 6

7th

Clamps 7 Drill Rigs 7

8th.

Inner channel central channel 8

9th

Collection room 9

10th

Exit channels 10

11th

Adapter 11, injection head

12th

Inner channel 12

13th

Inner channel 13

14th

Feed pump 14

15th

Reservoir 15 for a hardenable plastic mass

16th

Feed pump 16

17th

Storage container 17 for the curing plastic compound

18th

Collecting channel 18, gap

19th

Mountains 19

20th

static mixer 20, mixing elements

21st

Insert component 21 Mixer housing

22nd

Check valve / ball valve 22

23rd

Pressure sensor 23

24th

Motor 24, pump drive

25th

Hose 25, pipe

26th

Motor 26, pump drive

27th

Hose 27, pipe

28th

Control device 28, control

29th

On / off switch, switch 29

30th

Seal, seal

31st

Half shell 31

32nd

Half shell 32

33rd

Recess 33

34th

Recess 34

35th

Bead 35

36th

Bead 36

37th

End face, exit surface 37

38th

Shut-off valve 38, electromagnetic

39th

Check valve 39, electromagnetic

40th

Line 40

41st

Line 41

Borehole cross section with a diameter D ₁ .
Outer diameter D _{A of} the boring bar 1
Inner diameter of the thread D _i
average diameter D2 = (D _A + D _i ) / 2

Claims (19)

1. A process for setting rock bolts,
   in which a bolt rod with an inner channel is introduced into a drill hole,
   a free-flowing, self-hardening mass is pressed through the inner channel,
   the finished drill hole is filled with the mass and the mass hardens in the drill hole with the bolt rod remaining in the drill hole,
   characterised in that
   the hardening mass is made from a mixture of a hardenable plastic material and a curing plastic material,
   in that the hardening plastic material and the curing plastic material are supplied in a mixed state to the inner channel of the drill rod over a predetermined delivery time F,
   in that the plastic materials are so selected and, at a mixing point located a short distance upstream of or in the inner channel, are brought together in such a mixing ratio and mixed to form the mixture that a defined hardening time H is produced, wherein the delivery time F and the hardening time H are matched to one another in such a way
   that the delivery time substantially corresponds to the hardening time and substantially results in a complete filling of the flow section with the curing mixture between the mixing point and the exit of the drill hole.
2. A process according to Claim 1,
   characterised in that
   the inner channel and the drill hole are flushed with air during and/or after the drilling procedure, and in any case prior to the introduction of the curing mixture.
3. A process according to Claim 1,
   characterised in that
   the mixer is arranged in the inner channel.
4. A process according to Claim 1,
   characterised in that
   the mixer is a static mixer arranged upstream of the inner channel.
5. A process according to Claim 1,
   characterised in that
   the viscosity of the curing mixture in the hardening time is at least 100,000 Pa sec.
6. A process according to Claim 1,
   characterised in that
   the curing mixture hardens to such an extent in the hardening time that the torque of the drill rod in the drill hole is greater than the torque which is required to release the drill rod from the drill chuck holding it.
7. A process according to Claim 1,
   characterised in that
   a substance or plastic material is added to the curing mixture or one of the components and results in a precross-linking of the components with an increase in the viscosity to more than 500 Pa sec, preferably more than 1000 Pa sec, within and preferably at the start of the hardening time.
8. A process according to Claim 1,
   characterised in that
   the entrance of the inner channel of the drill rod is blocked by a non-return valve which is permeable in the filling direction.
9. A process according to Claim 1,
   characterised in that
   the hardenable and the curing plastic material is delivered over the delivery time F at a pressure-independent delivery quantity per unit time.
10. A process according to one of Claims 1-9, characterised in that
    the supply of the plastic materials and optional admixtures is switched off or otherwise terminated if a predetermined limit pressure is exceeded.
11. A process according to one of Claims 1-10, characterised in that,
    taking into account the delivery characteristics of the hardening and the curing plastic material, the fill time for the fill volume V to be filled downstream of the mixing point satisfies the equation: $$\mathrm{V}=\mathrm{k\; x}{{}_{0}f}^{\mathrm{H}}\left({\mathrm{q}}_{\mathrm{A}}\mathrm{+}{\mathrm{q}}_{\mathrm{H}}\right)\mathrm{dt};$$

    

    
    where
    V = fill volume of the inner channel downstream of the mixing point and the drill hole
    q_A = delivery quantity per unit time of the hardenable plastic material
    q_H = delivery quantity per unit time of the hardening plastic material
    dt = time increment
    H = hardening time
    K = constant taking into account site-dependent conditions, in particular the temperature and the quality of the rock.
12. A process according to Claim 1,
    characterised in that
    the plastic components are fed by an injection head (adapter 11),

    ➢ which is continually connected by means of lines to the delivery pumps of the plastic components, which delivery pumps are carried on a transport vehicle (drill truck),

    ➢ which is movably guided between a rest position and an operating position on the drill truck, and

    ➢ which, in the operating position, may be connected in pressure-tight manner by way of a connecting piece to that end of the bolt rod which projects out of the drill hole.
13. A process according to Claim 12,
    characterised in that

    ➢ in the injection head, a stop valve is located in each of the feed lines of the plastic components for the purpose of closing or opening the feed line,

    ➢ in that both stop valves may only be opened and/or closed synchronously with one another in normal operation, and

    ➢ in that the drive motors of the pumps may preferably be switched off in each case by way of a pressure sensor located in the respective feed line when a predeterminable maximum pressure is reached.
14. A process according to Claim 12,
    characterised in that
    the plastic lines, which are formed in the injection head and are connected to hoses on the supply side, lead into a smooth, preferably planar, face on the side facing the connecting piece (connecting side of the connecting piece), which face may be flushed by a highpressure jet, preferably a water jet, after the connecting piece has been disconnected.
15. A process according to Claim 12,
    characterised in that
    the connecting piece comprises two half shells which may be moved relative to one another perpendicular to the flow direction of the plastic materials guided on the inside and, in the assembled condition, enclose in pressure-tight manner, or otherwise connect, the injection head on the one hand and that end of the bolt rod which projects out of the drill hole on the other.
16. A process according to Claim 12,
    characterised in that
    the feed lines of the plastic materials are guided separately from one another in the injection head and in that the plastic materials are brought together in the connecting piece.
17. A process according to Claim 16,
    characterised in that
    the static mixer is arranged in the inner channel of the bolt rod.
18. A process according to Claim 16,
    characterised in that
    the static mixer is arranged in the connecting piece.
19. A process according to Claim 18,
    characterised in that
    the static mixer is constructed in a tube shape with mixing elements located in its mixing pipe and is preferably surrounded by a plastic pipe,
    in that, in the assembled condition, the half shells of the connecting piece form a guide channel which lies tightly against the mixing pipe and in which the mixing pipe is preferably form-fittingly, yet readily detachably, fixed at its two ends for support against the entry pressure of the plastic materials entering the mixer.

Images