Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Arrangement for injecting and affixing a reinforcing
or anchoring element in a rock wall.
Field of the invention
The present invention relates to an arrangement and a method for affixing
reinforcing and/or anchoring elements in rock walls in accordance with the
preamble of claim 1 and in accordance with claim 13.
io Background of the invention
Work on and in rock walls often results in problems relating to crack
formations, the danger of rock slides or rock slips and other hazards that
make it
necessary to reinforce the rock wall. For example, such problems may occur in
the
building of tunnels or rock cavities, and may also apply to open - air rock
walls in
is the construction of roads, highways and the like. In such cases
reinforcement is
most often achieved with the aid of different methods in which reinforcement
elements, normally in the form of reinforcing rods or reinforcement rounds or
the
like anchored in holes drilled in the rock wall. So-called rockbolts and roof
bolts are
examples of reinforcing and/or anchoring elements.
20 A well known and simple method of affixing reinforcement elements in a
rock wall involves firstly the injection of cement or like material into a
hole in the
rock wall. This hole may be an already existing hole in the rock wall,
although the
hole will be a separately pre-drilled hole in the majority of cases. A
reinforcing
element is then inserted into the cement, whereafter the entire cement package
is
25 allowed to harden. As the cement hardens it will shrink somewhat and
because
there is no other form of anchorage in the rock wall than that afforded by the
adhesion of the cement to the rock face, there is often the danger that the
entire
cement-"plug", including the reinforcement element, will loosen and at times
even
fall out of the hole.
30 Another problem experienced when working with and in rock walls is that
moisture and water may obtain ingress through cracks for instance, which often
results in the need to seal such cracks. When holes are drilled for the
reinforcement of rock walls as described above, leakages also often occur as a
result of puncturing the natural screen that was present prior to drilling. A
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2
punctured screen is often sealed by injecting some kind of sealing agent into
the
drilled holes. One example of such a sealing agent is cement grout or concrete
injected into the hole. However, these sealants are not able to penetrate out
into
the actual cracks and consequently the leakage problems remain in many
instances. Another method of sealing the rock is to cover the entire inner
surface
of the rock wall with concrete or some other suitable material for instance.
Neither is it permitted to secure reinforcing bolts in water-conducting holes
in several instances, but that it must first be ensured that the hole is dry
before
securing such bolts.
The insertion of a sealing agent or filler in a rock-wall hole is often
carried
out with the aid of a so-called packer. A packer typically includes a tubular
part
fitted to the end of a tubular drill bit or to a conduit for delivering some
type of
sealant, and an expandable cuff, made for instance of a rubber-like material,
is
disposed on the tubular part. When the cuff is caused to expand, the packer
will be
held firmly to the inner surface of the hole by friction, and therewith seal
against
the walls of the hole. The sealant subsequently injected into the hole is thus
unable to run out while still in a liquid state, provided that the packer
remains
seated in the hole.
Prior publication WO 99/56001 teaches an arrangement for reinforcing
2o and sealing a rock wall, said arrangement comprising a reinforcing rod that
is
connected to an injection element that includes an injection pipe and a check
valve. The reinforcement rod is permanently connected to the check valve and
is
inserted into a pre-drilled hole together with the injection element. The rod
is
anchored in the hole and an expandable seal ensures that injected material is
unable to run back out of the hole and the injection material is injected into
the
hole via the injection pipe and a check valve, wherein the check valve
includes a
cuff that prevents injection material being pressed back via the valve. The
injection
phase is effected at an overpressure, wherewith injection material shall also
be
capable of penetrating any possible cracks that open into the hole. Cement and
concrete are mentioned as examples of injection material. The seal is expanded
by tightening a nut disposed beneath the seal and therewith compress the seal,
via a washer or like device. The nut and the washer can be removed upon
completion of the injection phase and after the material has hardened,
wherewith
the seal is allowed to return to its non-expanded state, whereafter the seal
may
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also be removed. Remaining parts of the arrangement are left permanently in
the
drilled hole on the other hand. One drawback with this known arrangement is
that
it cannot be re-used and is therefore expensive. Another drawback is that
there is
always a risk of corrosion attack in the space that remains in the lower part
of the
hole after having removed the seal, nut and washer, despite subsequently
filling
the space with a filling material, due to the fact that parts of the injection
device still
remain in the hole.
In such cases there is also a need of fixating in the rock anchoring
devices which enable other devices to be secured in or to the rock wall. This
may
io apply, for instance, to affixing rockbolts, affixing reinforcement nets in
the case of
injection processes, affixing a protective net to prevent loose pieces of rock
or
stones from falling down onto a road surface or somewhere else, providing a
suspension point for different devices and elements used in mining and
tunnelling
practices, affixing ventilation equipment comprising fans, blowers and ducts,
channels/drums for other purposes, lighting, etc.
Summary of the invention
The aim of the present invention is to provide an arrangement and a
method which will resolve these problems and satisfy the needs mentioned
above.
2o This aim is achieved by means of an arrangement that has the novel features
set
forth in the characterising clause of the accompanying claim 1, and by means
of a
method that has the characterising features set forth in claim 13.
Thus, the inventive arrangement comprises a coupling which is connected
to a reinforcing and/or anchoring element, and an injection pipe which is
connected to the coupling means at a front end that faces inwardly in the hole
and
which is also provided with connecting means for connection to an injection
medium supply means, wherein the arrangement also includes an injection
medium check valve and an expandable seal, and wherein the invention is
characterized in that the arrangement has the form of a separate unit that can
be
3o disengaged from the reinforcing and/or the anchoring element upon
completion of
the injection phase.
The advantage afforded by this arrangement is that solely the end of the
reinforcing and/or the anchoring element is exposed within the hole, and no
other
parts remain. An additional advantage is that it is much simpler to seal-off
the
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remaining hole and the end of the reinforcing and/or the anchoring element
than is
possible in the case of the earlier known technique, by injecting some type of
filler
into the hole subsequent to completion of the injection phase. This greatly
reduces
the risk of corrosion attack. Alternatively, it may be elected not to fill the
remaining
part of the hole with filler and, instead, obtain the advantage of being able
to use
the free end of the reinforcing/anchoring element in the hole as an anchorage
and
securing point for diverse equipment. Examples of such equipment have already
been mentioned above.
Another advantage afforded by constructing the injection arrangement as
io a separate unit is that it can be removed from the hole upon completion of
the
injection phase so as to enable it to be re-used in a new hole, even
repeatedly.
The invention thus affords significant cost savings. A particularly beneficial
embodiment of the invention thus enables the arrangement to be re-used.
According to another beneficial feature of the invention, the arrangement
is is characterized in that the coupling means has an internally threaded
coupling
end for connection with an externally threaded end of the reinforcing and/or
anchoring element. The coupling means and the injection pipe comprise a single
entity, which affords the advantage of greater mechanical strength than would
otherwise be the case, eliminates the risk of these components being separated
20 from each other after having been screwed together and the entire
arrangement
shall be unscrewed from the anchoring point, and enables the arrangement to be
handled more practically from a general aspect. The coupling means is
beneficially
also designed so as to facilitate the release of the arrangement from the
surrounded injected material upon completion of the material injection phase
and
25 subsequent to hardening of the material. This can be achieved by causing
the
coupling means, which is typically cylindrical, to taper conically to a slight
extent in
a direction inwardly in the hole, or to coat the outer surface of the coupling
means
with Teflon for instance, or with some readily elastic or resilient material.
Other
coupling means may, alternatively, be greased. A combination of these proposed
3o alternatives is also feasible.
According to one feature of the arrangement, the seal has the form of a
sleeve disposed around the injection pipe. The sleeve will then function
beneficially as an inner seal defining wall, wherewith the seal is caused to
expand
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radially outwards between the outer wall of the injection pipe and the inside
of the
hole for sealing abutment with both outer wall and inner surface.
According to one variant, the seal has the form of a mechanically
expandable sleeve.
According to another variant, the seal has the form of a sleeve that
includes double walls and that can be expanded by injecting a pressurised
medium into the sleeve between said walls. Consequently, the inventive
arrangement also includes means for delivering pressurised medium to the seal.
According to a first embodiment, the check valve is disposed at the front
lo end of the injection pipe. This embodiment is beneficial when the
reinforcing
and/or anchoring element is a solid rod and when the injection medium shall be
pressed out into the hole behind the coupling means but in front of the seal.
According to a second embodiment, the arrangement is characterized in
that the coupling means includes an axially extending and through-passing
aperture and is designed to enable it to be coupled to a tubular element that
forms
said reinforcing and/or anchoring element; and is further characterized in
that the
check valve functions to regulate the supply of injection medium from the
injection
pipe via the aperture in the coupling means and through said tubular element
and
out at the front end thereof. The benefit afforded by this embodiment is that
the
injection medium can be fed out at a point much further into the hole,
depending
on the length of the tubular reinforcing and/or anchoring element, and there
penetrate into the cracks etc. present in the rock wall.
A further benefit achieved by this embodiment is that the tubular element
forming the reinforcing and/or anchoring element may consist of a drill rod
that
includes internal channels and also a drill bit for boring said holes,
wherewith the
check valve regulates the supply of injection medium from the injection pipe
via
the aperture in the coupling means, through said drill rod and out through the
drill
bit.
The inventive method of injecting and securing a reinforcing and/or
3o anchoring element in a rock wall comprises the following method steps:
- inserting a reinforcing and/or anchoring element in a hole in the rock wall
with said element coupled to an injection means which constitutes a
separate entity or unit and includes means for coupling the injection means
to a reinforcing and/or anchoring element, an injection pipe which is
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connected to said coupling means at a front end facing inwardly in the hole
and which is also provided with connecting means for connection to an
injection medium supply means, wherein the arrangement also includes a
check valve for co-action with the injection medium and an expandable
seal;
- expanding the seal on the injection means so as to prevent injection
medium injected into the hole from exiting from the hole during and after the
medium injection phase;
- delivering injection medium to the hole via said injection arrangement and
said check valve;
- terminating the injection phase and allowing the injection medium to
harden;
- causing the expandable seal to return to its non-expanded state after
termination of the injection phase and allowing the injection medium to
harden at least partially; and
- removing the injection means as a unit.
This method affords the benefits that no part of the injection means will be
left in the hole, therewith greatly reducing the risk of corrosion in the hole
and also
2o enables the injection means to be re-used as it is.
Another beneficial feature is that the hole is drilled with the aid of a drill
rod provided with a drill bit where said drill rod later forms the reinforcing
and/or
anchoring element, and that drilling takes place when the injection means has
already been coupled to the reinforcing and/or anchoring element. According to
the inventive method, the injection phase can be carried out via a through-
penetrating aperture in the coupling means and also via an internal channel in
the
drill rod and out into the hole via the drill bit fitted to the front end of
the drill rod.
According to the inventive method, the injection medium is beneficially
injected at an overpressure, wherewith the hole is first filled with injection
medium
which then penetrates into any cracks present in the surrounding rock, said
injection means opening out into the hole so as to thereby seal the cracks.
Among
other things, this avoids the risk of the injected medium solely forming a
plug in the
hole without being anchored to the surrounding rock. As earlier mentioned, any
plug that forms can easily loosen from the sides of the hole and therewith
fall out
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of the same. By overpressure is meant in this case a pressure of at least 1
bar and
normally between 1- 2 bar and up to 100 bar or even at a higher pressure if
necessary. With regard to sealing the rock, the pressure applied must also be
adapted to the nature of the rock into which the medium is injected. The rock
is
sometimes of a poor quality, i.e. very porous and perhaps also water-
conducting,
wherewith a high pressure is required in sealing the rock, in some instances
up to
several hundred bar. A high injection pressure eliminates the risk of pockets
of air
and water. The reinforcing element is also anchored more securely in the rock.
The magnitude of the pressure required will also depend on the extent of
io the rock covering above the area to be sealed, in other words on how much
rock is
located above this area, and will also depend on the static pressure exerted
by the
ground water. The ground water pressure will also be high in the case of rock
that
includes an open-air lake, therewith requiring the application of a high
injection
pressure.
Another beneficial feature afforded by the inventive method is that the
injection means can be re-used for the injection and anchoring of a new
reinforcing
and/or anchoring element in the rock wall. This clearly constitutes an
economic
benefit in comparison with earlier known arrangements of the one-time-use only
type.
Finally, a further beneficial feature afforded by the invention is that
subsequent to removing the injection means the reinforcing and/or anchoring
element will have a free end located within the hole sealed with the injection
medium, this free end being available for the attachment of further equipment.
This
is of enormous benefit. Examples of equipment that can be secured with the aid
of
an anchoring element include ventilation systems in tunnel roofs, ventilation
ducts,
fans, blowers and lighting equipment. The anchoring element can also be used
to
hang-up other equipment used in tunnelling practices for instance. Further
examples include devices for fastening reinforcing nets, protective nets
against
stone and rock slides, etc. The anchoring element can also be used solely for
securing a device that pressurizes the rock as it is.
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8
Brief description of the drawings
The present invention will now be described in more detail with reference
to the exemplifying embodiments illustrated in the accompanying diagrammatic
drawings, in which
Figure 1 is a diagrammatic sectioned side view of a first embodiment of
an inventive arrangement that includes a first variant of the
expandable seal with the seal shown in a non-expanded state;
Figure 2 is a diagrammatic side view corresponding to Figure 1, but
showing the expandable seal in an expanded state;
io Figure 3 is a diagrammatic sectioned side view of a second embodiment
of an arrangement according to the present invention, showing
a second variant of the expandable seal with the seal in a non-
expanded state;
Figure 4 is a diagrammatic side view corresponding to Figure 3, but
showing the expandable seal in an expanded state;
Figure 5:1-8 illustrates the method of using an arrangement according to the
first embodiment;
Figure 6: 1-6 illustrates the method of using an arrangement according to the
second embodiment;
2o Figure 7 is a diagrammatic sectioned side view of a third embodiment of
an arrangement according to the present invention, with the
expandable seal shown in a non-expanded state;
Figure 8 is a diagrammatic side view corresponding to Figure 7, but
showing the expandable seal in an expanded state; and
Figure 9 is a diagrammatic sectioned side view illustrating an example of
use in accordance with the inventive method.
Those components shown in the figures that are common to the various
embodiments have been identified with the same reference signs.
3o Detailed description of the invention
Figures 1 and 2 illustrate a first embodiment of an arrangement 1 for
injecting and securing a reinforcing element and/or anchoring element 2 in a
rock
wall 3, in accordance with the present invention. For the sake of simplicity
the
arrangement will be referred to solely as an injection means in the following
text.
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Correspondingly, the reinforcing and/or anchoring element 2 will be referred
to
solely as the reinforcing element in the following text. This should in no way
be
understood as limiting the scope of the invention. The reinforcing and/or
anchoring
element 2 may also consist of solid iron material or a hollow tube.
Figures 1 and 2 show a first embodiment of the injection means 1 coupled
to the reinforcing element 2, wherewith the mutually coupled members are
together inserted into a hole 4 in a rock wall 3. The injection means
constitutes a
separate unit. The illustrated first embodiment of the injection means I
includes a
first variant of a packer-type expandable seal, namely a mechanically
expandable
io seal 5. The injection means I also includes means 7 for connection to a
means
(not shown) for supplying an injection medium 8. This supply means preferably
includes a pump, which enables the injection medium to be supplied at an
overpressure. A suitable injection medium is a cement grout or a chemical
liquid.
The connection means 7 is provided at the end of an injection pipe 9 remote
from
the hole, this end also being called the outer end. A check valve 10 is
provided in
connection with the front end of the injection pipe line, i.e. the end
proximal to the
hole 4. This check valve may be of a known kind, e.g. of the kind known from
prior
publication WO 99/56001. The check valve 10 shall, in any case, be able to
withstand the pressure at which the injection medium is injected, so as to
ensure
that the injection medium will not flow back out through the valve. The
injection
means 1 also includes coupling means 15 on the front end of the injection
pipe.
This coupling means has an internal thread 16 and is screwed to an externally
threaded end 17 of the reinforcing element 2. The reinforcing element 2 is
thus of
a typical kind provided with an external thread.
The hole 4 in the rock wall 3 may be an existing hole or a hole that was
made particularly for the purpose concerned.
Figure 1 shows the injection means 1 and the reinforcing element 2 when
they have just been inserted into the hole 4, prior to expansion of the seal
5. This
figure also corresponds to Figure 5:2.
Figure 2 shows the injection means 1 when the seal 5 has been caused to
expand and therewith seal against the inner wall of the hole 4. As will be
seen, the
seal 5 of this embodiment has the form of an expandable sleeve disposed around
the injection pipe 9. The seal 5 is made of an elastic, resilient, springy
material or
some other yieldable material, such as rubber, so as to enable its shape to be
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changed. The seal is caused to expand mechanically with the aid of a known,
separate clamping tool 20, which is shown in Figure 5:3. The tool 20 exerts a
force
on the outwardly facing end of the seal 5 and, by virtue of an abutment means
or
stop 18 provided at the inner end of the seal that prevents the seal from
moving
5 inwardly along the injection pipe 9, the seal will be compressed axially and
therewith expand radially so as to come into sealing abutment with the inner
wall
of hole 4. Provided at the outwardly facing end of the seal is some type of
locking
device that prevents the seal from sliding back outwardly and return to its
non-
expanded state subsequent to removing the clamping tool 20. The locking device
io will preferably be comprised of locking washers or plates 19 in the form of
a known
particular type of spring washer.
Figures 3 and 4 illustrate a second embodiment of an arrangement 1 for
injecting and securing a reinforcing element and/or anchoring element 2 in a
rock
wall 3, in accordance with the present invention. In the case of this second
embodiment, the injection means differs from the injection means of the first
embodiment, in that the expandable seal consists in this case of a second
variant
in the form of a pneumatically or hydraulically expandable seal 50. The seal
50
thus has the form of a sleeve which includes double walls and which can be
expanded with the aid of a pressurized medium delivered into the sleeve, i.e.
into
the space between said walls. According to this second embodiment, the
injection
means therefore includes means for delivering said pressurized pneumatic or
hydraulic medium 58. Thus, in addition to the means 7 for connecting the
injection
means to an injection medium supply means, as shown at 8, the injection means
also includes means 51 for connection to a pneumatic or hydraulic pressure
source, not shown. A connecting line 52 is provided between the connection
means 51 and the space between the walls of the sleeve-like seal, so that
pressurized medium is transported to the space between the double walls and
therewith cause the seal 50 to expand; see Figure 4. Other parts of the
injection
means are the same as those in the first embodiment, with the exception that
the
use of locking washers or plates at the outwardly facing end of the seal is
not
necessary in the case of the second embodiment. Nevertheless, the material
from
which the seal is made is an elastic, springy material or a material that is
non-rigid,
such as a rubber material, so that its form can be changed.
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The coupling means 15 in both embodiments has the form of a truncated
cone that has an internal thread 16. The conical shape of the coupling means
is
primarily intended to facilitate release of said means from the injected
material 8
subsequent to said material having hardened, whereafter the injection means 1,
including the coupling means 15, shall be removed completely from the hole 4.
The coupling means 15 may also be treated on its outer surface with a removal
facilitating means, for instance with a Teflon coating or a coating of some
elastic
material. Alternatively said outer surface may be greased.
The inventive method will now be described with reference to Figures 5:1-
io 8 and 6:1-6, these figures being related to the first and the second
embodiment
respectively.
Figures 5:1 and 6:1 illustrate respectively a rock wall 3 in which a hole 4
has been drilled, this being the normal procedure. Figures 5:2 and 6:2
illustrate
respectively the insertion of a reinforcing and/or anchoring element 2 into
the hole
4 in the rock wall 3. The element 2 is coupled to an injection means 1 which
constitutes a separate unit and includes a means 15 for coupling the injection
means 1 to the reinforcing and/or anchoring element 2, connecting means 7
being
intended for connection to a means for the supply of injection medium 8, an
injection medium check valve 10 and an expandable seal 5 and 51 respectively.
Figure 6:2 also shows the expansion of the seal 50 of the injection means,
which in this case is achieved with the aid of a delivered hydraulically or
pneumatically pressurized medium, such as water or air for instance. Figure
6:3
shows the appearance of the expanded seal 50. The seal 50 is in sealing
abutment with the injection pipe and all the walls of the hole and prevents
injection
medium injected into the hole 4 from flowing out of the hole during and after
the
injection phase. Correspondingly, Figure 5:2 shows how the first variant of
seal 5
is expanded mechanically with the aid of a tool 20.
Figures 5:4 and 6:3 illustrate delivery of injection medium 8 to the hole 4,
via said injection means 1 with its coupling means 7 for connection to the
injection
medium delivery means, and the injection pipe 9 and the check valve 10. The
cavity in the hole 4 and around the reinforcing element 2 is filled with
injection
medium 8 and when the cavity is full, the injection medium is pressed out into
rock
cracks and fissures that open into the hole 4, by virtue of the overpressure
to
which the injection medium is subjected.
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Respective Figures 5:5 and 6:4 show the injection means 1 and the hole 4
after completion of the injection phase, while the injection medium 8 is
allowed to
harden.
Figure 6:4 also shows how the expandable seal 50 is caused to return to
its non-expanded state after completion of the injection phase and after the
injection medium 8 has hardened at least partially. This is achieved by either
returning the pressurized expansion medium to the pressure source or releasing
it
to the surroundings. With regard to the mechanically expandable seal 5, Figure
5:6
shows how the seal is allowed to return to its non-expanded state by removing
the
io locking washers 19.
Respective Figures 5:7 and 6:5 illustrate the removal of the injection
means 1, comprising the means 15 for coupling the injection means to the
reinforcing and/or anchoring element 2, the check valve, seal and injection
medium delivery means. The injection means can thus be released from the
reinforcing element, by unscrewing the coupling means 15 from the reinforcing
element 2.
Finally, respective Figures 5:8 and 6:6 illustrate the hole 4 subsequent to
the removal of the injection means. As will be evident from the figures, the
reinforcing element 2 leaves in the hole 4 a free end 17 which can be used to
secure diverse equipment, as earlier described. Naturally, it is also possible
to fill
the remainder of the hole with injection medium or with some other type of
filler if
so preferred.
Figures 7 and 8 illustrate a third embodiment of an injection means 1 and
the attachment of a reinforcing element and/or anchoring element 62 in a rock
wall
3, in accordance with the present invention. This embodiment differs from the
two
earlier embodiments, primarily by virtue of the fact that the coupling means
65 is
also hollow, i.e. provided with a through-passing aperture or bore. In this
case, the
check valve 10 is located between the front end of the injection pipeline and
the
aperture in the coupling means 65. When also including a hollow reinforcing
3o element 62, this enables injection medium to be fed right up to the
innermost end
of the reinforcing element, where the medium is then pressed out into the hole
4. It
is then possible, in particular, to allow the reinforcing element 62 to
comprise a drill
rod that has an internal channel, i.e., in principle, a thick-walled pipe
which is fitted
with a drill bit 63 at its front end. This embodiment can thus be used to
first drill the
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hole 4 in the rock wall 3, prior to said injection phase and the affixation of
the
reinforcing element 62. The coupling means 65 is also conveniently provided
with
an internal thread 66 in this case, for connection with an external thread 67
on the
drill rod 62.
In the case of the third embodiment, the expandable seal 60 is comprised
of a mechanically expandable seal.
This third embodiment also includes means 7 for the supply of injection
medium 8. This supply means may consist of a swivel device. The injection pipe
9
includes an extension 68 along the supply means. This extension is intended
for
io connection to a drilling machine and is preferably solid. The hole is
drilled by
relatively slow rotation of the drill rod, at a speed of about 100 - 200 rpm,
preferably combined with a certain amount of impact energy.
In order to achieve rotation of the drill rod 62 via the injection pipeline
and
its extension 68, it is necessary to mount the injection medium supply means 7
on
is the injection pipe in a manner to prevent rotation of said supply means as
other
components rotate. In this connection, it is convenient to use a separate
expansion device 69 for the seal 60, this expansion device being the subject
of an
individual, separate patent application filed on the same day as the present
application and by the same applicant. This expansion device 69 may be placed
2o around the injection pipe 9 in a manner which prevents it from rotating
with the
injection pipe. This expansion device is based on a piston-cylinder-device and
is
controlled either pneumatically or hydraulically.
The arrangement and method according to this third embodiment function
in accordance with the following. The drill bit 63, which is of a disposable
type, a
25 so-called lost bit, a drill rod 62, the injection means 1, the injection
medium supply
means 7 and preferably also the separate expanding device 69 are assembled
together and connected to a drilling machine. Drilling of the hole is
commenced,
alternatively there is used an existing hole of some kind, and the arrangement
is
inserted as far as possible into the hole before starting the drilling phase.
Drilling is
30 terminated when a desired bore depth has been reached, and the seal 60 is
then
expanded so that the entire device will be held firmly in the hole by means of
friction. The injection medium 8 is then delivered at an overpressure through
the
arrangement and out into the hole, via the drill bit 63 which includes
suitable
channels to this end. The injection phase is terminated and injection medium
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14
allowed to harden. The expandable seal 60 is then caused to return to its non-
expanded state, by releasing the pressure in the expansion device 69. The
entire
arrangement can then be loosened from the drill rod 62 by unscrewing the
coupling means 65 from the end of the drill rod and the entire arrangement can
be
removed optionally for use in a further hole. The drill bit thus remains in
the hole
together with the firmly injected drill rod and functions as a reinforcing
element and
can also be used as an anchoring element when it has a free end similar to
that
obtained in the other described embodiments.
It should be added that although the injection pipe and the coupling means
io of all illustrated embodiments have been shown as being a single unit it
will be
understood that this is not a requirement of the actual concept of the
invention.
It will also be understood that it is, of course, also conceivable to include
a
variant of the invention that is adapted for a non-hollow drill rod which is
connected
to the coupling means and used to drill the hole and then function as a
reinforcing
or anchoring element. Such a variant would then include coupling means, check
valve and seal constructed in accordance with the principle illustrated in the
two
first embodiments, while the injection medium supply means and the hole
sealing
expansion means must be designed to permit rotation of other components,
corresponding to that illustrated in Figures 7 and 8 respectively.
Figure 9 shows how the free end 17 of the reinforcing element 2 in the
hole 4 can be used to attach equipment. In this case there is included a
threaded
rod 30 that carries a washer 31 and a nut 32 which is used to tension the rock
itself by tightening the nut and/or for fastening, e.g., a reinforcing net or
the like. An
internally threaded sleeve 33 of a known kind is used as a coupling means
between the reinforcing element and the threaded rod.
It will be understood that the invention is not restricted to the illustrated
exemplifying embodiments thereof, and that modifications and changes can be
made in various ways by the person skilled in this art within the scope of the
accompanying claims.
