Note: Descriptions are shown in the official language in which they were submitted.
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METHOD AND SYSTEM FOR GENERATING A DRILLING PATTERN, AND A
ROCK DRILLING RIG
Field of the invention
The present invention relates to rock excavation, and in particular to a
method and
system for generating a drilling pattern during rock excavation. The invention
also
relates to a rock drilling rig, as well as a computer program and a computer-
readable
medium that implement the method according to the invention.
Background of the invention
Rock excavation, in particular underground rock excavation, may be carried out
using
various techniques, where excavation using drilling and blasting technology is
a
commonly used method. The excavation may consist in the creation of a rock
cavity
having a predefined shape and geographical location. This may be the case, for
example, when creating tunnels or other kinds of underground cavities.
Excavation
using drilling and blasting is, in general, carried out in a manner in which
drilling is
performed in rounds, where a round of holes is drilled to thereafter be loaded
with
explosives to blast the rock. Following removal of rock being detached by the
blasting, a new round of holes are drilled to blast a subsequent portion of
the cavity
to be created. This is repeated until excavation of the desired cavity has
been
completed.
In order to achieve a rock excavation that results in a desired cavity being
created,
each round of holes are being drilled according to a drill plan, or drilling
pattern,
which essentially determines location, direction, length and possibly diameter
of the
holes to be drilled. The object of the drilling pattern being to create a
cavity having a
cross-sectional shape and geographical alignment that corresponds to the
cavity the
creation of which being the task at hand.
Cavities of this kind may be of various designs. For example, the cavity may
be
designed to have essentially the same cross-sectional appearance following an
essentially straight line. However, as is oftentimes the case, properties of
the cavity,
e.g. in terms of cavity cross section and curvature, may vary along the length
of the
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cavity. This may require utilization of different drilling patterns for
different sections of
the cavity to be excavated.
With regard to, for example, tunnels, but also other kinds of cavities, these
are
oftentimes associated with highly precise requirements regarding conformance
with
the desired cavity cross section and geographic alignment/extension. For
example,
lining such as concrete lining may be utilised, where over-break of rock
result in an
increased consumption of lining and oftentimes also an increase in the
requirement
of rock reinforcement. Insufficient breaking, under-breaking, on the other
hand, may
require additional drilling and blasting to obtain the desired cavity. Hence,
well-
designed drilling patterns and subsequent drilling in accordance with the
drilling
patterns is essential in order to achieve the desired result.
Summary of the invention
It would be advantageous to achieve a method and system that may be utilised
to
obtain a drilling pattern for rock excavation that may reduce surplus rock
when
excavating a cavity in conformance with predetermined geographical
alignment/extension.
According to the present invention, it is provided a method for generating a
drilling
pattern for excavating a cavity in rock, the drilling pattern determining
holes to be
drilled in a face of the rock, the determination of the holes to be drilled
being a
determination of location, direction and length of the holes to be drilled,
the holes
being arranged to be drilled by a drilling rig comprising at least one feed
beam
carrying a drilling machine, the at least one feed beam having a first end
arranged
to, during drilling, face the rock to be drilled and a second end being
opposite to said
first end. The method comprises:
- generating a drilling pattern comprising holes having a drillability, the
drillability of
said holes being determined when generating said drilling pattern by ensuring
a
manoeuvrability of said second end of said at least one feed beam in relation
to
surrounding rock.
The drilling pattern may be generated prior to excavation of the cavity
commences.
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The drilling pattern may comprise holes to be drilled subsequently to the
generation
of the drilling pattern.
The drilling machine may be slidable along the feed beam.
As was mentioned above, the drilling pattern being used in rock excavation
using
drilling and blasting technology is an important factor in order to achieve a
cavity
having a cross section and geographical extension that conforms to a high
extent to
the planned alignment of the cavity. Drilling patterns, also known as drill
plans, define
the location, position, of the holes to be drilled in a rock face of the rock
to be
excavated, and also the direction and length of the holes. The drilling
pattern may
also determine the diameter of the hole to be drilled, where e.g. holes along
a
periphery of the contour, i.e. cavity profile, outline or cross section, to be
drilled may
be of a different diameter than holes more to the centre of the rock portion
to be
excavated. Contour is used in the following as a representation of cavity
profile/outline/cross-section.
The drilling pattern is generated on the basis of the contour/profile of the
cavity to be
created, and a plurality of consecutive rounds of drilling and blasting are in
general
required to create the desired cavity, such as a tunnel.
Drilling patterns may be generated in various manners as is known to the
person
skilled in the art, and embodiments of the invention may be utilised in
combination
with any such method. Drilling patterns are oftentimes generated beforehand,
i.e.
prior to excavation of the cavity commences, e.g. in a control/planning
centre, to then
be downloaded to the rock drilling rig for use in the excavation.
Rock excavation often results in surplus rock being broken, and this is also
often
necessitated by constructional constraints that hinders optimal positioning of
a drilling
rig/drilling machine used in the excavation, which thereby renders it
difficult to drill
holes that result in excavation without surplus rock being broken. Surplus
cavity
formed during tunnel excavation is oftentimes subject e.g. to subsequent
concrete
lining, where the surplus rock being broken also results in additional
consumption of
concrete e.g. in concrete lining operations and may also generate an increase
in
required rock reinforcement following blasting. Drilling patterns are in
general
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designed to reduce the amount of surplus rock being broken, but it may not
always
be possible to drill completely according to the predetermined drilling
pattern.
According to embodiments of the invention, the drilling pattern is generated
following
drilling and blasting of a previous round, and when generating the drilling
pattern, this
is designed to comprise holes having a drillability, i.e. the holes are to be
drillable by
the rock drilling rig. The drillability of the holes is determined by ensuring
a
manoeuvrability of the feed beam in relation to surrounding rock to ensure
that the
surrounding rock does not hinder positioning of the feed beam required to
drill the
hole. In particular, in order for a hole to be drillable, it is ensured that
the rear end of
the feed beam, i.e. the end facing away from the rock face during drilling,
can be
manoeuvred in relation to the surrounding rock to ensure that a hole can
actually be
drilled.
In this way, a drilling pattern can be generated that ensures that holes of
the drilling
pattern are also drillable in reality, so that adaptions of the drilling
pattern during
ongoing drilling of a round due to holes not being possible to drill can be
reduced,
which thereby may reduce the risk of over-breaking and/or under-breaking of
rock
resulting from adaptions of the drilling pattern during ongoing drilling.
According to embodiments of the invention, the manoeuvrability of the second
end of
the feed beam in relation to surrounding rock utilises a representation of the
rock
surrounding said second end. For example, manoeuvrability of the second end of
the
feed beam in relation to surrounding rock can be ensured when generating the
drilling pattern utilising a representation of the cavity in a coordinate
system of the
cavity. Using the position of the drilling rig in this coordinate system, the
manoeuvrability of the feed beam can then be determined using the
representation of
the cavity, where the rock outside the cavity contour in the representation of
the
cavity represents the surrounding rock
According to embodiments of the invention, a manoeuvrability of the second end
of
the feed beam in relation to surrounding rock when generating the drilling
pattern is
ensured utilising a representation of actual rock walls, resulting from
blasting of one
or more previous rounds of drilling, where the representation of the actual
rock walls
can be generated e.g. by one or more scanners, e.g. located on the drilling
rig. In this
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way, manoeuvrability of the feed beam can be determined in relation to
actually
excavated rock, which, e.g. in case of over-breaking, may allow further
manoeuvrability and thereby drilling of further/other holes than would be
possible to
drill according to the predetermined cavity contour.
5 According to embodiments of the invention, a manoeuvrability of the
second end of
the feed beam in relation to surrounding rock is determined utilising a
representation
of a cross section, contour, of the cavity at a distance from a representation
of the
face to be drilled substantially corresponding to the length of the feed beam.
It is in
general the second, i.e. rear, end of the feed beam that will impose
limitations, and in
this way manoeuvrability can be determined by determining the manoeuvrability
of
the second end in relation to the cavity contour prevailing at its location. A
profile
representing actually excavated rock may also be utilised.
Furthermore, in addition to taking into account the second(rear) end of the
feed
beam, further portions of the feed beam between the first end and the second
end
may also be taken into account when determining drillability. For example, in
case
there are protrusions in the rock along the length of the feed beam,
manoeuvrability
of the feed beam may be determined in relation to such protrusions as well.
The rock drilling rig may comprise a plurality of feed beams, each carrying a
drilling
machine, and the determination may be performed for the particular feed beam
that
is to drill an intended hole.
According to embodiments of the invention, the manoeuvrability of the feed
beam is
determined when the cross section, contour, of the cavity is narrowing in the
direction
of excavation, and/or a curvature of the cavity is changing. It is oftentimes
in
situations of these kinds that limitations regarding the manoeuvrability of
the feed
beam may have the most negative impact when drilling a drilling pattern where
this
manoeuvrability has not been accounted for.
According to embodiments of the invention, the manoeuvrability of the feed
beam is
determined when the cross section, contour, of the cavity is changing such
that
different drilling patterns are used for consecutive rounds of drilling and
blasting.
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According to embodiments of the invention, the manoeuvrability of the feed
beam is
determined when excavation of the cavity has progressed to an extent at least
corresponding to the length of the feed beam.
According to embodiments of the invention, when generating the drilling
pattern, a
face contour is determined to represent the rock face to be drilled, the face
contour
constituting a cross section of the cavity in a navigation plane adjacent the
rock face
to be drilled is determined.
The drilling pattern can be determined as an aggregate drilling pattern
comprising
determination of a first drilling pattern for a first part of the face
contour, and at least
one second drilling pattern for at least one second part, different from the
first part, of
the face contour. A maximum hole length of holes of the first drilling pattern
can be
arranged to be longer than a maximum hole length of holes of the second
drilling
pattern.
The first part of the face contour can be determined using a first contour and
a
second contour, where the first contour is a representation of the cross
section of the
cavity at a distance from the face contour substantially corresponding to the
length of
the feed beam, and where the second contour is a representation of a cross
section
of the cavity at a distance from the face contour substantially corresponding
to the
maximum length of the holes to be drilled.
According to embodiments of the invention, the first part of the face contour
is
determined utilising interpolation between the first contour, which is located
in one
direction from the face contour and the second contour, which is located in
another
direction from the face contour in the plane of the face contour. The
interpolation is
made in the plane of the face contour. This first part of the face contour
represents a
part for which holes having a length determined by the distance between the
face
contour and the second contour can be drilled. For example, the maximum length
of
holes to be drilled in the round. Since the face contour defines the maximum
surface
to be drilled, the interpolation may be delimited also by the face contour so
that the
first part forms part of the face contour and does not extend outside the face
contour
even if this would be the result from the interpolation. In this way, in
particular
because of the use of the first contour, a part/portion of the face contour
can be
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determined, where it can be ensured that the holes of the drilling pattern can
be
drilled to a desired, e.g. full length, without feed beam manoeuvring imposing
limitations once drilling is started.
The method may be arranged to be utilised in situations where the
interpolation
results in the first part of the face contour will not comprise the full face
contour.
The first part may further be determined utilising projection of the first
contour and/or
said second contour onto the face contour instead of utilising interpolation.
In this
way, the part of the face contour for which holes of full length are drilled
can be
reduced to, instead, increase the remaining part, for which, according to the
below,
holes of a reduced length is drilled. For example, this may be utilised when
otherwise
the remaining part of the face contour becomes undesirably small so it may
e.g. be
difficult to get room for further, or a desired number of, holes to be drilled
in the
remaining part.
With regard to the portion of the face contour for which holes having full
length are
not to be drilled, i.e. the remaining part of the face contour, it can be
determined, e.g.
on the basis of the width of this portion of the face contour and/or the
number of
holes to be drilled on this remaining portion, at least one intermediate
contour
between the face contour and said second contour, each of said at least one
intermediate contours representing a cross section of the cavity at different
distances
from the face contour towards the second contour. These at least one
intermediate
contours are then used when generating a drilling pattern of said remaining
portion of
the face contour, and a drilling pattern is generated for different
parts/portions of said
face contour for each of said intermediate contours utilising said
intermediate
contour, respectively, and said first contour e.g. as described above using
interpolation and/or projection. The holes of these at least one additional
drilling
pattern will hence have a shorter length than the holes of the first part of
the face
contour above. The reduced hole length in combination with the first contour
ensures
that also the remaining part of the face contour can be drilled using a
drilling pattern
where manoeuvrability of the feed beam is still ensured.
A drilling pattern encompassing the face contour can consequently be
determined,
where the drilling pattern is an aggregate of drilling patterns for different
parts of the
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face contour. Further, when holes of drilling patterns for different parts of
said face
contour are located within less than a first distance from each other, thereby
considered to have overlapping coverage of the rock to be drilled, holes of at
least
one of the drilling patterns can be omitted. For example, the hole having the
shortest,
or longest for that matter, length, can be arranged to be omitted.
It will be appreciated that the embodiments described in relation to the
method
aspect of the present invention are all applicable also for the system aspect
of the
present invention. That is, the system may be configured to perform the method
as
defined in any of the above described embodiments. Further, the method may be
a
computer implemented method which e.g. may be implemented in one or more
control units of a rock drilling rig.
Further characteristics of the present invention and advantages thereof are
indicated
in the detailed description of exemplary embodiments set out below and the
attached
drawings.
Brief description of the drawings
Fig. 1A-B illustrates an exemplary representation of a part of a tunnel to be
excavated;
Fig. 2 illustrates an exemplary embodiment of a rock drilling apparatus in
which
embodiments of the invention may be utilised;
Fig. 3 illustrates an exemplary method according to embodiments of the
invention;
Fig. 4 illustrates an exemplary method for reducing the risk that under-
breaking of
rock occurs;
Fig. 5 illustrates a further exemplary method according to embodiments of the
invention for generating a drilling pattern.
Fig. 6 illustrates an exemplary representation of a part of a tunnel to be
excavated,
including contours utilised when generating a drilling pattern according to
embodiments of the invention;
Fig. 7 illustrates determination of a contour for drilling of full-length
holes, forming part
of a rock face to be drilled;
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Fig. 8 illustrates the cross sectional appearance of the contour for drilling
of full-
length holes in relation to the rock face to be drilled;
Fig. 9 illustrates the cross sectional appearance of the contour for drilling
of holes
having a reduced length in relation to the rock face to be drilled;
Fig. 10 illustrates a method for determination of contours for drilling holes
having a
reduced length, the contours forming part of a rock face to be drilled;
Fig. 11 illustrates holes to be drilled from a face contour towards bottom
contours
according to embodiments of the invention;
Fig. 12 illustrates a method for increasing the cross sectional appearance of
the
contour for drilling of holes having a reduced length in relation to the rock
face to be
drilled;
Detailed description of exemplary embodiments
Embodiments of the invention will be exemplified in the following with
reference to
examples relating to excavation of a tunnel. Figs. 1A-B illustrates an
exemplary
representation of a section of a tunnel to be excavated in rock. The tunnel
may be
any kind of tunnel for any suitable use, and e.g. comprise a tunnel forming
part of a
mine, or a tunnel for road or railway transport.
According to the example, the tunnel is represented by a tunnel line TL, which
essentially is defined by points TLn-3, TLn-2... TLn+2 which may be
interconnected.
The extension, alignment, of the tunnel in the longitudinal direction may
hence be
obtained by interconnecting the tunnel line points. The disclosed section of
the tunnel
to be excavated represents a section of the tunnel about n tunnel line points
into the
tunnel. The tunnel line points are defined in a 3D-coordinate system being
used in
the excavation, e.g. a global coordinate system or a coordinate system local
to the
area of excavation, so that the desired tunnel can be excavated in conformity
with the
pre-planned tunnel alignment.
Any suitable number of tunnel line points may be used in the representation of
the
tunnel, where the number e.g. may depend on the length of the tunnel to be
excavated, and any suitable, constant or varying, distance between the tunnel
line
points may be used, e.g. in dependence of curvature. For example, the distance
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between tunnel line points may represent the length of the longest holes to be
drilled
during a round for subsequent blasting. The length of the holes to be drilled
may e.g.
correspond to the length along a feed beam that a drilling machine may slide,
and
e.g. be in the order of 0-10 metres.
5 In order to obtain a 3D-representation of the tunnel alignment, e.g. a
representation
of the desired tunnel cross section, in the following denoted tunnel contour,
or tunnel
profile, may be defined for each tunnel line point, e.g. in a plane
perpendicular to the
tunnel line TL. The tunnel contours of different tunnel line points may be
defined in a
same plane, but may also be defined in different non-parallel planes. An
example of
10 a tunnel contour 101 is disclosed in fig. 1B, exemplifying a tunnel
contour 101 of
tunnel line point TLn, and which also indicates the location of the associated
tunnel
line point TLn in relation to the tunnel contour 101. For simplicity, the
tunnel line point
TLn is shown as being located essentially in the centre of the tunnel contour
101 of
fig 1B, but it may be arbitrarily located on, or principally anywhere on a
plane of, the
tunnel contour 101 for as long as the relation between tunnel line point and
tunnel
contour is defined. Positioning of the desired tunnel contour to encompass the
associated tunnel line point may be advantageous e.g. from a navigation point
of
view during actual excavation.
The interconnected tunnel line points together with the associated tunnel
contours,
which may vary in shape from one tunnel line point to another can be used to
form a
3D-volume through interpolation representing the tunnel and which is being
defined
in a coordinate system to allow excavation at a desired location.
Consequently, the
tunnel is represented by tunnel contours distributed along the tunnel line TL
representing the desired extension of the cavity to be excavated. In case the
tunnel
contours differ from one tunnel line point to another, e.g. interpolation can
be utilised
in a straight-forward manner to obtain a tunnel cross-section also at any
point
between the defined tunnel line points. In case the tunnel contours are
defined in a
same plane 2D-interpolation may be utilised, while otherwise 3D-interpolation
may be
utilised to determine an intermediate tunnel contour in any desired plane.
Tunnel/cavity excavation of this kind often involves generation of a drill
plan, in the
following denoted drilling pattern, for drilling of a set, or round, of drill
holes in a rock
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face for subsequent blasting. The drilling pattern defines the holes to be
drilled, e.g.
in the coordinate system of the tunnel, and may define position, length and
direction
for each hole. Holes having different diameters may also be drilled, and hence
a hole
diameter may be defined by the drilling pattern as well. Following drilling of
a round,
the drilled holes are charged with explosive material that is detonated
following
drilling and charging of the holes of the drilling pattern.
After the explosion, broken rock is taken away and following scaling, if
required, i.e.
clearing and loosening of cracked and/or partly loose rock resulting from the
blasting,
a new round is drilled and blasted to progress the excavation of the tunnel.
This is
then repeated until the complete volume of the desired tunnel/cavity has been
excavated. When generating a drilling pattern of a round to be drilled the
object is in
general to design the drilling pattern such that the cavity formed by the
blasting
following the drilling results in a cavity having a spatial extension that at
least clears
the rock encompassed by the 3D-representation of the desired cavity, such as
the
cavity defined by an interpolation of the tunnel line points and associated
contours. In
reality surplus rock is oftentimes excavated in addition to the breaking of
rock forming
the desired cavity. This is due to a difficulty in breaking rock precisely
according to
desired cavity boundaries. It is, however, usually a requirement that the
desired
cavity is also excavated in full, i.e. the complete cross section of any given
point of
the tunnel being cleared from rock, and in order to ensure that at least this
is
accomplished surplus rock is oftentimes broken to ensure that under-breaking
does
not take place. The drilling pattern may be designed in an attempt to reduce
the
breakage of surplus rock as much as possible while still ensuring that at
least the
desired cavity is excavated.
Fig. 2 illustrates an exemplary movable rock drilling rig 201 that may be
utilised e.g.
in tunnel excavation. The rock drilling rig 201 is an underground drilling rig
and is
shown in position for drilling a round of holes in a rock face 202 during
tunnel
excavation, e.g. along the tunnel line TL of fig. 1A.
As can be seen in fig. 2, the rock drilling rig 201 according to the disclosed
example
is provided with three booms 203-205, each of which is carrying a drilling
machine
206-208 via feed beams 209-211. Accordingly, the disclosed rock drilling rig
201 may
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drill up to three holes at a time. Drilling rigs of the disclosed kind are
known per se.
The drilling machines 206-208 are, in this example, hydraulically driven and
power
supplied from one or more hydraulic pumps 212, which in turn are driven by one
or
more electric motors and/or combustion engines 213, also in a manner known per
se.
The drilling process may be controlled by an operator from a cabin 215.
The drilling rig 201 further comprises a control system comprising at least
one control
unit 214, which controls various of the functions of the drilling rig 201,
e.g. by suitable
control of various actuators/motors/pumps etc. Drilling rigs of the disclosed
kind may
comprise more than one control unit, where each control unit, respectively,
can be
arranged to be responsible for different functions of the drilling rig.
The drilling rig 201 is arranged to be repositioned as excavation progresses
and
comprises, according to the present example, wheels 216, 217 for allowing
drilling rig
movability. Crawler drives or other suitable means may alternatively be used
to allow
manoeuvring of the drilling rig 201.
Fig. 2 hence discloses a drilling rig that following a previous blast and
clearing of
broken rock has been moved forward in the excavating direction, i.e. along the
tunnel
line TL, towards the rock face 202 resulting from the previous blast and the
drilling rig
201 has been positioned for drilling the subsequent round for blasting of the
next
section of the tunnel/cavity to be excavated. In order to correctly excavate
rock
according to the predetermined tunnel alignment, the exact position of the
rock
drilling rig 201 in the prevailing coordinate system must be determined. This
can be
accomplished in various ways and, for example, by aligning one of the feed
beams,
e.g. feed beam 211 to a laser beam of a theodolite (not shown), where the
position of
the theodolite in turn has been established using fixed points.
The drilling rig in 201 general comprises a local rig coordinate system, and
through
the use of the drilling rig coordinate system the position of the drilling rig
can be
determined using the location of the feed beam in the drilling rig coordinate
system
and the location of the feed beam as determined in the coordinate system of
the
tunnel. In addition to the feed beam being aligned with a laser beam of a
theodolite,
the position of the feed beam along the laser beam must also be determined.
This
can be performed e.g. by straight-forward measurement or in any other way.
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For example, the length of the tunnel that so far has been excavated from the
beginning of the excavation, i.e. the drilled and blasted length of the
tunnel, may e.g.
be marked on the tunnel wall to facilitate positioning of the drilling rig. As
is realized,
any other suitable method of positioning the drilling rig in the coordinate
system of the
tunnel to be drilled may be utilized. According to embodiments of the
invention, the
drilling rig is provided with fixed points, which may be used to position the
drilling rig
using e.g. a theodolite, and where the rig fixed points are also defined in
the
coordinate system of the drilling rig, so that thereby e.g. the position of a
feed beam
may be determined in the coordinate system of the tunnel.
As before mentioned, prior to drilling of the rock face 202 commences, a
drilling
pattern is generated, and fig. 3 illustrates a highly schematic flowchart for
generating
a drilling pattern to be drilled prior to blasting the current rock face 202.
The positions
of the holes to be drilled on the rock face are schematically illustrated by
"x"
markings, where these positions are determined by the drilling pattern. The
drilling
pattern to be used is oftentimes determined prior to the excavation of a
tunnel
commences e.g. in a planning centre, where the holes are planned such that the
subsequent blasting as close as possible corresponds to the desired cavity to
be
excavated. The generation of the drilling pattern that is optimal from an
excavation
point of view, e.g. with regard to surplus rock being broken, may be
difficult, in
particular when excavation is in progress and the excavation has progressed to
a
position along the tunnel line that does not correspond to a position for
which drilling
is planned to be performed on the planning stage. According to the invention,
it is
provided a method for generating a drilling pattern that takes further factors
into
account when generating the drilling pattern in an attempt to reduce the
amount of
surplus rock being broken during the excavation.
This is accomplished by means of a method 300 according to fig. 3, which
starts in
step 301 by determining whether a drilling pattern is to be generated. This
may be
initiated e.g. by an operator of the drilling rig 201, e.g. by suitable input
to the drilling
rig control system, or by any other suitable means. The method continues to
step 302
when a drilling pattern is to be generated while otherwise the method remains
in step
301. In step 302 a representation of the location of the rock face to be
drilled is
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determined, e.g. by positioning the drilling rig according to the above using
the
coordinate system of the drilling rig in combination with the position of the
drilling rig
in the coordinate system of the tunnel, where the representation of the rock
face can
be expressed in the coordinates of the coordinate system being used for
excavation
of the tunnel. The rock face is often represented by a navigation plane, which
can be
arranged to be located in any conventional manner with regard to the rock
face, e.g.
as discussed below with reference to figs. 5-12.
When the position of the rock face 202 in the coordinate system of the tunnel
has
been determined, a desired contour/profile of the tunnel section to be drilled
and
longitudinal alignment may also be determined, e.g. through the use of
interpolation
using the tunnel contours of the tunnel line point or points closest to the
rock face
202.
In step 303, the drilling pattern is generated on the basis of the
predetermined
contour and alignment of the tunnel section about to be drilled. The drilling
pattern
may basically be generated according to any of the various known technologies
for
generating a drilling pattern, but according to embodiments of the invention,
in
addition, further aspects are taken into account when generating the drilling
pattern.
In general when generating a drilling pattern, holes to be drilled close to
the periphery
of the rock face are subject to limitations regarding possible hole direction.
This is
due to the inherent diameter/size of the drilling machine/feed beam. That is,
it is not
possible to drill precisely along a contour outline but drilling will have to
be performed
slightly outwards in relation to the desired direction to make room for
drilling
machine/feed beam when drilling the next round of holes following blasting of
the
current round. This is known per se, and the general principle is illustrated
in fig. 4,
where in which a desired width of a tunnel to be drilled is indicated with a,
in which
the actual drilling is represented as a saw tooth pattern 401, in which the
distance b
is essentially governed by the dimensions of the drilling machine/feed beam,
and
where the distance b ensures that the width of the tunnel can be maintained at
the
subsequent round. That is, if the distance b is made smaller in one round,
this may
make drilling difficult in a following round, so that the drilling e.g. will
be directed more
outwards due to space limitations. Fig. 4 merely illustrates a general
principle, and
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the outward angulation c may be determined in any suitable manner, in general
in an
attempt to limit over-breakage of rock, where the outward angulation c may
vary from
one round to another.
However, according to embodiments of the invention, other parameters than the
5 limitations of fig. 4 are taken into account. Therefore, when generating
the drilling
pattern in step 303 in fig. 3, limitations imposed by the already excavated
portion of
the tunnel regarding manoeuvrability of the rear end 209B, 210B, 211B of the
feed
beam 209-211 is also taken into account when generating the drilling pattern.
The
tunnel walls of the already excavated portion of the tunnel will impose
restrictions on
10 possible manoeuvring of the feed beam(s) of the drilling rig so that
holes that would
be desired to drill from an excavation point of view e.g. to reduce the amount
of
surplus rock being excavated may not in reality be possible to drill due to
feed beam
space limitations, which may render a required manoeuvring of the feed beam in
order to drill the holes according to the determined drilling pattern
impossible. This
15 may be the case, for example, when the cavity to be drilled is
narrowing, and/or when
cavity is not following a straight line.
When generating the drilling pattern, a hole desired to be drilled may be
checked,
step 304 regarding manoeuvrability as soon as a hole has been determined to be
drilled, or following the generation of the complete drilling pattern, where
holes being
found to be unsuitable from a drillability perspective may be re-determined.
This may
result e.g. in holes being replaced by holes having another direction and
possibly a
different hole length. An iteration may be performed until all holes are
considered
drillable in step 304, in which case the method is ended in step 305. The rock
face
may then be drilled according to the determined drilling pattern.
Hence, according to embodiments of the invention, a drilling pattern may be
generated that will also be drillable, and that may not be subject to
manoeuvring
difficulties due to surrounding rock being unaccounted for. In this way it can
be
ensured that rock is excavated to an extent sufficient to provide the desired
cavity
while simultaneously breaking of surplus rock may be reduced by creating a
drilling
pattern that take the actual conditions prevailing at the location of the rock
face
regarding manoeuvrability of the feed beam into account to thereby create a
drilling
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pattern that may result in less surplus rock being excavated than otherwise
might be
the case. According to embodiments of the invention, the disclosed method may
be
most beneficial in sections where the contour is changing, in particular
narrowing
and/or the tunnel is curving or the curvature of the tunnel is changing.
According to embodiments of the invention, the representation of the tunnel in
the
tunnel coordinate system, e.g. as determined by the tunnel line TL and
associated
contours according to the above, be used to determine possible manoeuvrability
of
the feed beam and thereby drillability of a hole when generating the drilling
pattern.
That is, the cavity that is assumed to have been excavated up to the face to
be drilled
may be utilised, where a 3D-representation of the assumed cavity may be
obtained,
for example, using interpolation according to above.
According to embodiments of the invention, a contour of the already excavated
portion of the tunnel at a distance from the face to be drilled substantially
corresponding to the length of the feed beam may be used to determine
limitations
regarding the manoeuvrability of the end of the feed beam facing away from the
drilling direction when determining drillability of a hole.
According to embodiments of the invention, the actual rock walls are instead
used to
determine drillability of the holes of the drilling pattern. This may be
accomplished, for
example, by scanning the rock walls as the excavation progress. Since there
oftentimes is an over-breakage of rock, this may render further feed beam
manoeuvring possibilities, so that holes that may not be considered drillable
using the
theoretical extension of the cavity may in reality still be drillable.
Further, embodiments of the invention relates to particular methods for
generating
the drilling pattern that take limitations regarding manoeuvrability of the
feed beam
into account.
In the following, therefore, an inventive method 500 of fig. 5 according to
embodiments of the invention for generating a drilling pattern will be
exemplified. The
method will be exemplified with further reference to figures 6-12.
In FIG. 6 a tunnel line TL is illustrated which is similar to the tunnel line
of fig. 1A, but
where in addition the desired outline 601 of the tunnel as seen from above is
also
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illustrated. In addition, the actual rock walls 602 of the already excavated
portion of
the tunnel are shown, including the rock face 603 about to be drilled as the
excavation progress. As has been discussed above, the tunnel line points are
defined in the coordinate system being used in the excavation, and in the
present
example drilling has reached a point between TLn and TLn+1. Even if, prior to
the
excavation of the tunnel commences, it may be an intention to drill
consecutive
rounds at consecutive tunnel line points, drilling may not progress precisely
according
to pre-planned drilling patterns, where each round of drilling and blasting
may be
expected to reach the next tunnel line point of the tunnel line TL. For
example, the
blasting may not break the full length of a hole, and/or a larger portion of
rock may be
broken, e.g. due to more porous rock. According to embodiments of the
invention,
however, the drilling pattern for the next round is established only once the
location
of the rock face to be drilled has been determined, and is independent from
the
current progress in relation to the tunnel line points.
The exemplified method in fig. 5 starts in step 501, where, similar to the
method of
fig. 3, it is determined whether a drilling pattern is to be determined. When
this is the
case, the method continues to step 502 where a face contour FC of the current
rock
face to be drilled is determined. The face contour FC is determined for a
plane, here
denoted navigation plane NP as is commonly the case, from which hole length,
direction etc. of the holes to be drilled is determined. As can be seen from
fig. 6, the
resulting rock face 603 from the preceding blast is uneven, and may vary
considerably. The navigation plane NP may be determined such that it
substantially
or completely clears the rock face 603 to be drilled, but the navigation plane
NP may
also be arranged to partially or fully intersect the rock face 603 to be
drilled.
The navigation plane NP may be defined in various ways, and according to the
present example, the navigation plane NP is defined such that it is
perpendicular to a
line, dashed line 605, representing an intended drilling direction of the
round to be
drilled. The intended drilling direction may, as in the present example,
differ from the
direction of the tunnel line TL at the point where the tunnel line TL is
intersected by
the navigation plane NP. For example, the direction of drilling may be
determined by
a line 605 that intersect the tunnel line TL at the point where the tunnel
line TL is
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intersected by the navigation plane NP, and where the line 605 also intersects
the
tunnel line TL, point 604, at some suitable distance from the navigation plane
NP.
The distance from the navigation plane NP to point 604 may correspond to, or
substantially correspond to, the longest hole length to be drilled in the
round for
which the drilling pattern is generated. The distance from the navigation
plane NP to
the point 604 may also be any other suitable distance, greater or smaller than
the
longest hole length to be drilled in the round. For example, the distance may
be set
or changed from a pre-set value e.g. by an operator in case it is desired to
change
the drilling direction, and in which case the navigation plane may be
automatically
adjusted to be e.g. perpendicular to the drilling direction. In the present
example the
navigation plane NP is hence determined such that line 605 is normal to the
navigation plane NP. The navigation plane NP is hence defined independently
from
the general appearance of the rock face 603 to be drilled, and e.g. need not
be
parallel to this rock face 603, but may be angled considerably in relation to
the actual
rock face.
The navigation plane NP may also be defined independently from a drilling
direction,
and may essentially have any suitable angle in relation to e.g. the tunnel
line TL
and/or drilling direction 605 and/or rock face. There exist various methods in
the art
for determining a navigation plane NP, and any such method may be utilised.
For
example, the navigation plane NP can be arranged to be determined e.g. by an
operator of the drilling rig and/or other person involved in the generation of
drilling
patterns. Further, an intended drilling direction may be defined according to
any
suitable criteria and may have any suitable direction and hence need not be
defined
according to the example using tunnel line points described herein.
The face contour FC is determined in the navigation plane NP, where the face
contour FC can be determined by 2D or 3D interpolation as explained above
using
the tunnel contours of TLn and TLn+1, depending on whether these tunnel
contours
are in a same plane or not, to obtain the face contour in the navigation plane
NP. The
tunnel line contours of adjacent tunnel line points may differ in shape from
one tunnel
line point to another, e.g. if the tunnel is narrowing or otherwise changing
shape, and
may be defined in different planes, e.g. by the curvature changing such as in
the
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present example, where tunnel line contours of tunnel line points TLn and
TLn+1 are
also in different planes with respect to the navigation plane NP. The
navigation plane
NP hence need not, and according to the present example is not, be
perpendicular to
the tunnel line at the point where this is crossed, and the face contour FC
will
therefore differ from the tunnel line contour even if the tunnel contours of
adjacent
tunnel line points TLn and TLn+1 are the same. The exemplified method is
perhaps
most advantageous when conditions for generating the drilling pattern differ
from one
round to another, in particular when the tunnel is narrowing and/or the tunnel
is
curving or the curvature of the tunnel is changing.
The method then continues to step 503 in which, in a similar manner to the
above, a
bottom contour BCO is determined. The bottom contour BCO is determined in a
bottom plane BP, which is a plane at a distance from the face contour FC. The
bottom plane may be defined to be located at a distance from the face contour
FC,
e.g. defined by line 605 above, and hence at a distance e.g. corresponding or
substantially corresponding to the longest length of the holes to be drilled
in the
round for which the drilling plan is generated. The bottom plane BP may also
be
arranged to be located at any other, greater or smaller, distance from the
face
contour FC. The location of the bottom plane BP may also be arranged to be
adjusted by an operator of the drilling rig, e.g. by changing pre-determined
distance
between face contour and bottom plane in case this is desired, e.g. to extend
or
reduce the distance between the face contour/navigation plane and the bottom
plane
BP. The distance between the face contour and bottom plane may hence exceed
the
longest hole length to be drilled. Further, in case the planes are angled with
respect
to each other, the distance between the planes will vary in dependence on
where on
the planes measurement is made, and hence the distance may be both greater and
smaller than the longest hole length to be drilled even if e.g. the distance
along the
tunnel line equals the longest hole length to be drilled. The bottom plane BP,
and
thereby bottom contour BCO may be arranged to be perpendicular to the tunnel
line
TL where this is intersected, i.e. at point 604 in the present example. The
bottom
plane BP may alternatively be arranged to be perpendicular to the line 605,
and
hence be parallel to the navigation plane NP. The bottom plane may also be
defined
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in any other suitable manner. The bottom contour BCO may be determined using
2D
or 3D interpolation, in this case using tunnel line points TLn+1, TLn+2.
In step 504 a further contour, a limiting contour LC, is established. The
limiting
contour LC is also interpolated using adjacent tunnel line contours, TLn-2,
TLn-1, in a
5 manner similar to the above at a distance from the face contour FC, and
in a direction
from the face contour FC opposite the drilling direction. The distance between
the
face contour FC and the limiting contour LC may e.g. be selected to equal the
length
of the feed beam of the drilling rig. The limiting contour LC is used to take
surrounding rock of the already excavated portion of the tunnel into account
10 according to the above to determine drillability of the holes when
determining the
drilling pattern so that the manoeuvrability of the feed beam is taken into
account.
The limiting contour LC may be interpolated using tunnel line contours as
above, but
if a scanned representation of the actual rock wall of the already drilled
portion of the
tunnel is available this can be used instead to increase accuracy when
determining if
15 holes are drillable or not. Furthermore, the limiting contour LC may be
selected such
that it's normal vector coincides with the direction of navigation and hence
the limiting
contour LC is parallel to the face contour FC.
According to the present exemplary method for generating a drilling pattern at
the
current location of the drill rig, a drilling pattern encompassing the face
contour FC to
20 be drilled is formed by generating separate drilling patterns for
different portions of
the face contour FC. Therefore, in step 505 a first maximum contour MCO is
generated. This maximum contour MCO represents the maximum possible portion of
the face contour FC where it is possible to drill the holes having the maximum
length
being drilled during the excavation of the tunnel, while ensuring
manoeuvrability of
the feed beam. The maximum contour MCO is arranged to be in the navigation
plane
NP, i.e. the same plane as the face contour FC. The boundaries of the maximum
contour MCO is limited by the periphery of the face contour FC, since this is
the
maximum surface to be drilled, but MCO is also delimited by a 3D-interpolation
using
the limiting contour LC and the bottom contour BCO in the plane of the face
contour
FC. This is illustrated in FIG. 7 by dashed interpolation lines 701 and 702.
The
resulting contour MCO, delimited also by the face contour FC, is shown as the
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hashed area of fig. 8, which hence shows the face contour FC and the
determined
MCO. The area MCO, consequently, represents the portion of the face contour FC
that may be drilled with full-length holes when drilling the next round. The
area
resulting from the interpolation that is located outside the face contour FC,
i.e. the
hashed area 801, is disregarded since this area is not to be drilled.
When the maximum contour MCO has been determined according to the above, a
drilling pattern is generated, step 506, for the maximum contour MCO, which
hence
constitutes a drilling pattern of holes to be drilled from face contour FC to
the bottom
contour BCO. The drilling pattern for the maximum contour MCO may
alternatively not
be generated until all contours according to the below have been established.
That
is, the various contours are first established, whereafter the drilling
pattern is
generated for the various portions of the face contour. The drilling pattern
of the
maximum contour MCO can be generated according to any suitable method for
generating a drilling pattern for drilling a contour towards a bottom contour,
where
various methods are known in the art. The drilling pattern of maximum contour
MCO
will not, since this contour does not encompass the full face contour FC,
represent
the total volume that is to be drilled and blasted during the round to be
drilled.
Additional drill holes must be added in order to drill the full volume.
Therefore, the
remaining portion of the face contour, i.e. the non-hashed portion of fig. 8,
shown as
hashed in fig. 9 and denoted DC, is still to be drilled, but full-length holes
may not be
utilised due to the manoeuvrability limitations of the feed beam, but holes
having a
length being less than the maximum length of the holes of the round to be
drilled may
be used for this portion of the face contour.
In step 507, therefore, the difference surface, contour DC, constituting the
difference
between the face contour FC and the maximum contour MCO is determined. With
regard to this surface, a drilling pattern is to be generated where holes are
drilled to a
shorter length than holes being drilled when drilling the generated drilling
pattern of
the maximum contour MCO.
It is therefore determined a number of rows of holes to be drilled on the
difference
contour DC. This can be established, for example using rules regarding
distance
between holes to be used when generating drilling patterns, where this
distance can
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be dependent e.g. on the properties of the rock to be drilled, diameter of
holes to be
drilled, length of the section of rock that is about to be excavated in the
current round
etc., as is known per se. This determination regarding the holes, however, is
oftentimes already performed, and is therefore not part of the invention.
Hence, when
e.g. the applicable hole distance is established, a number of rows of holes to
be
drilled in the difference contour DC may also be determined.
The determined number of rows of holes to be drilled, and/or alternatively the
width of
the difference contour DC, is then used to establish a number n intermediate
bottom
contours BC1...BCn, step 507, to be used between the face contour FC and the
original bottom contour BCO. For example, one bottom contour can be generated
for
each, e.g. vertical or horizontal row of holes to be drilled in the difference
contour DC.
The intermediate bottom contours BC1...BCn can be generated in the same manner
as BCO above, i.e. through interpolation using the tunnel contours of the
adjacent
tunnel line points. With regard to the location of the bottom contours
BC1...BCn,
these can be arranged to be evenly spaced between the face contour FC and the
bottom contour BCO. That is, for example, if only one additional drilling
pattern is to
be generated, the additional bottom contour BC1 can be arranged to be
positioned at
half the distance from the face contour FC to the bottom contour BCO. The
distances
to the additional bottom contours/planes may also be determined in any other
suitable manner, e.g. in dependence of the curvature of the cavity to be
drilled.
According to the present example, two additional bottom contours BC1, BC2 are
generated, which are evenly spaced between the face contour FC and the bottom
contour BCO. This is illustrated in fig. 10, where the two intermediate planes
BC1,
BC2 are shown. Other distributions than even distances between contours may
also
be utilised. A drilling pattern may then be generated for each additional
bottom
contour BC1...BCn, step 508, where the additional drilling patterns can be
generated
using the above described principle, by interpolating, respectively, the
additional
bottom contours BC1...BC2 and the limiting contour LC in the plane of the face
contour, and further delimit by the face contour FC. This is illustrated by
the lines
1001, 1002 used in the interpolation in fig. 10, and the portion to be drilled
to a hole
depth delimited by BC1 is schematically indicated as MC1 portion of DC in fig
9, and
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the portion to be drilled to a hole depth delimited by BC2 is schematically
indicated as
MC2 portion of DC in fig 9. Portions of the face contour FC for which drilling
patterns
have already been generated, e.g. MCO, are disregarded. As was mentioned
above,
the drilling pattern for MCO may be generated after the portions MC1, MC2 have
been determined. Hence, when generating a drilling pattern for BC1, this will,
according to the present example, render one or more further row of holes to
be
drilled, essentially having a length corresponding to the distance between the
face
contour FC and the intermediate bottom contour BC1. Again, holes regarding
portions of the face contour FC for which a drilling pattern has already been
generated are disregarded. Furthermore, holes being too close to already
planned
holes, e.g. for the maximum contour MCO may also be disregarded, since the
already
planned holes in general will be holes of a longer length. Alternatively, such
holes
may be omitted from the drilling pattern of MCO instead.
When the drilling pattern for the first intermediate bottom contour BC1 has
been
generated, a drilling pattern is generated for the second intermediate bottom
contour
BC2 in a similar manner, which in this example will render one or more further
row of
holes to be drilled, essentially having a length corresponding to the distance
between
the face contour FC and the second intermediate bottom contour BC2, i.e. holes
having a yet shorter length. In addition to holes regarding portions of the
face contour
FC for which a drilling pattern has already been generated with respect to the
bottom
contour BCO, holes of the drilling pattern for the first intermediate bottom
contour BC1
are also disregarded, and also holes being too close to already planned holes
as
discussed above.
When drilling patterns have been generated for the bottom contour BC and the
intermediate contours BC1, BC2, consequently, an aggregate drilling pattern
covering the full face contour FC have been generated, and fig. 11
schematically
illustrates the holes to be drilled by solid lines extending from the face
contour FC to
the bottom contours, respectively. The aggregate drilling pattern may then be
drilled
one at a time or be treated as a single aggregated drilling pattern, step 509,
where
holes may be drilled in any order and not just one drilling pattern at a time.
The
method is then ended in step 510.
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The drilling patterns regarding the different bottom contours may also be
generated in
any other order, still for the same areas, but shorter holes may be maintained
instead
of longer holes in the border areas should this be considered advantageous,
e.g. to
reduce surplus rock. Also, the different portions MCO, MC1 etc. may be
determined
prior to the actual drilling patterns are being determined.
Furthermore, according to embodiments of the invention, the areas of the face
contour FC not covered by the maximum contour MCO may be enlarged, i.e. the
area
of MCO may be reduced. This may be carried out e.g. in order to make room for
one
or more further rows of holes in case the difference contour is determined to
be too
small, e.g. being too narrow. Such parameters may be pre-set in the control
system.
Enlargement of the difference area may be accomplished by reducing the size of
the
maximum contour MCO. For example, the limiting contour LC can be projected to
the
face contour FC in the navigation plane, instead of utilising interpolation,
thereby
further limiting the size of the maximum contour MCO. This is exemplified in
fig. 7 by
dotted line 710, which hence renders the maximum contour MCO smaller, thereby
increasing the area to be drilled using shorter hole lengths.
The projection may be used in combination with interpolation according to the
above,
but projection may also be utilised instead of the interpolation. That is, for
example,
only the limiting contour LC or a bottom contour BCO may be used in the
establishment of the maximum contour MCO /difference contour. Consequently,
according to embodiments of the invention, only the bottom contour BCO or
Limiting
contour LC is determined in the method of fig. 5.
According to the above example, projection of the bottom contour BCO onto the
face
contour FC may not impose any substantial differences. However, according to
other
situations, such as e.g. situations of the kind shown in fig. 12, projection
of the bottom
contour BCO onto the face contour FC may be suitable to use.
Fig. 12 illustrates a situation where the tunnel is narrowing, i.e. the
tunnel/cavity is
transitioning from a wider section to a narrower section. The line 1201
exemplifies
interpolation according to the above, which results in a maximum contour MCO
having a width corresponding to line 1203. According to the example disclosed
in fig.
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12, the maximum contour MCO can be reduced by projecting the bottom contour
BCO
onto face contour FC instead of utilising interpolation.
This is illustrated by line 1202, which represents projection of the bottom
contour BCO
onto the face contour FC and results in a maximum contour MCO having the
smaller
5 width indicated by line 1204 in the figure. This, in turn, increases the
part of the face
contour FC for which holes having a reduced length are to be drilled, the
increase of
the difference contour, i.e. reduction of the maximum contour MCO, being
indicated
by line 1205.
Finally, for the sake of simplicity, the bottom contours BCO, BC1, BC2 have
been
10 illustrated as at least essentially planar surfaces. This need not be
the case, but any
of or all of the bottom contours may take any desired shape.
Furthermore, the method for generating a drilling pattern has been described
above
as being carried out by a drilling rig that is present at a location where a
rock face is
about to be drilled. According to embodiments of the invention, the generation
of the
15 drilling pattern may be carried out by a computer e.g. in a planning
centre, where e.g.
a drilling pattern may be generated for any location of the cavity to be
drilled, so that
personnel e.g. may evaluate the generated the drilling pattern, and adjust
input
parameters to be used in the generation of the drilling pattern.
