Note: Descriptions are shown in the official language in which they were submitted.
BACKGROUND OF THE INVENTION
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- This invention relates to a support member capable of bearing an
axial compressive load, which may be used as a support in an
underground mine or in the construction industry or the like.
5 SUMMARY OF THE INVF.NTION
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According to the invention there is provided a support member
capable of bearing an axial compressive load which comprises an
elongate tube of a flexible material divided by dividing walls of a
flexible material into a plurality of compartments running the
10 length of the tube, at least some of the compartment being filled
with a particulate filler material.
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The support member may include restraining means encircling the
outside of the tube to restrain the tube from deformation in a
direction transverse to the longitudinal axis of the tube. The
restraining means may run the whole or only a part or parts of the
5 length of the tube. The restraining means may comprise any suitable
material such as weld mesh, diamond mesh, fencing wire, plastic
netting, a plastic mesh such as that covered by South African Patent
No~ 82/7300, a plastic or metal rope or a plastic or metal tape. In
all cases the restraining means must restrain deformation of the
10 tube in a direction transverse to the longitudinal axis of the tube,
especially when the support member is placed under an axial
compressive load.
As an alternative, the compartments around the circumference of the
tube may be left empty to restrain the tube from deformation in a
15 direction transverse to the longitudinal axis of the tube. It has
been found that leaving one or more empty compartments around the
~- circumference of the tube increases the strength of the tube to
deformation in a direction transverse to the longitudinal axis of
the tube.
20 The flexible material may be any suitable flexible material such as
a plastics material, an aluminium foil, paper, paper or plastic
laminated aluminium foil, or a thin metal sheeting. The flexible
material is preferably a plastics material. The plastics material
may be a conventional plastics material, a biaxially oriented
25 plastics material or a woven or non-woven fabric. Suitable plastics
include include high and low density polyethylene, polypropylene,
styrene based plastics, polyesters and polyvinyl chloride.
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~ 2
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The elongate tube divided into compartments preferably has a
honeycomb structure. The structure may be made, for example, by the
method described in United States Patent No. 4,478,659, by joining a
series of non-metallic sheets to each other by welding along their
5 lengths.
The particulate filler material which is used to fill the
compartments may be any suitable particulate material such as sand~
cement, crushed stone, a particulate containing sludge or slurry,
mine tailings, fly ash, river bed sediment, or bentonite, or a
10 mixture of two or more thereof.
Some or all o the compartments may include a rigid filler item such
as a wood, cement or metal pillar or prop. The area around the
pillar or prop in a compartment is then filled with the particulate
filler material. Such a pillar or prop serves to provide rigidity
15 to the support member especially before all the compartments have
been filled with the particulate material.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a front view of a support member according to the
invention; and
20 Figure 2 is a cross-sectional view along the line A-A in Figure 1.
DESCRIPTION OF PREFERRED EMBODIMENTS
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Referring to the drawings, a support member 10 comprises an elongate
tube 12 of a flexible material divided by dividing walls into a
plurality of compartments or cells 14. The elongate tube 12 divided
25 into compartments 14 has a honeycomb structure as can be seen from
Figure 2. This honeycomb structure is created by joining sheets of
the flexible material 16 to each other along join lines 18.
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At least some of the compartments 14 are filled with a particulate
filler material 20.
The support member 10 includes restraining means 22 being metal or
plastic bands located around the circumference of the elongate tube
5 12 to restrain the support member 10 from deformation in a direction
C which is transverse to the longitudinal axis D of the tube 12.
A method of constructing the support member 10 for supporting a
hanging wall 30 in a mine will now be described. Firstly, the tube
12, which is open at both ends, is located in position between the
10 foot wall 32 and the hanging wall 30 of the mine, with a gap of a
few centimetres between the top of the tube 12 and the hanging wall
30. As the tube is flexible, it requires to be supported initially
either by locating a wood, concrete or metal pillar o-r prop in one
or more of the compartments 14, or by attaching the tube 12 to the
15 hanging wall 30 so that it hangs down therefrom, or by any other
suitable means. Once the tube 12 is in position, and any pillars or
props to be used are in position, the particulate filler material 20
is filled into the compartments 14, e.g. by pumping the particulate
material 20 in. The particulate filler material 20 may be vibrated
20 in order to ensure that it settles and consolidates sufficiently.
The restraining means 20 are then located around the tube 12.
Thereafter, the gap between the top of the support member 10 and the
hanging wall 30 may be filled with wooden blocks or wedges or an
inflatable pillow 34 or the like. The inflatable pillow 34 may also
25 be filled with the particulate filler material. The support member
10 is now in a position to bear an axial compressive load.
As stated above, the elongate tube and dividing walls of the support
member of the invention are made of a flexible material which may be
a plastics material, thin metal sheeting, paper, or a laminate of
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one or more of these. The flexible material is preferably a
plastics material which may be a conventional plastics material, a
biaxially oriented plastics material or a non-woven fabric.
Where the flexible material is a non-magnetic material, the elongate
5 tube divided into compartments is preferably made by the method
described in United States Patent No. 4,478,659. This patent
discloses, inter alia, a method of joining a first sheet of two
sheets of a non-magnetic material which are joined to each other
along a join line to a third sheet of a non-magnetic material along
10 a join line. This method comprises the steps of locating the three
sheets close to a magnet with the third sheet adjacent the first
sheet, locating a body which is attracted by the magnet between the
first sheet and the second sheet so that the first sheet and the
third sheet are brought together in a zone between the magnet and
15 the body with the second sheet below the body, causing the first
sheet and the third sheet to be moved through the zone, and joining
the third sheet to the first sheet in the zone or immediately after
~ the third sheet and the first sheet have passed through the zone to
form the join line. Generally the first sheet and the second sheet
20 are joined to each other along two substantially parallel join lines
and the third sheet is joined to the first sheet along a join line
which is intermediate the join lines of the first and second sheets.
The result of this is a honeycomb structure. The sheets, when they
comprise a plastics material, may be joined to each other by heat
25 welding or by ultrasonic welding which creates a continuous welded
join line along the length of the sheets. Thus, preferably each
compartment of the elongate tube of the support member of the
invention comprises a cell in the honeycomb structure formed between
two adjacent sheets of a suitable material. Each cell may have a
30 round, square, diamond or hexagonal shape or any other suitable
shape.
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A similar honeycomb structure may be created in other ways. For
example, where the flexible material is paper, the honeycomb
structure may be formed by glueing the adjacent sheet of material to
each other along join lines.
5 The cross-sectional area of each cell of the honeycomb structure may
vary according to the use to which the support member is to be put.
Generally, each cell will have a diameter of lOOmm to l metre or
larger.
Where the flexible material comprises a flexible plastics material,
10 it may comprise a plastics film having a thickness of 50~m to 500~m.
The length of the elongate tube may be any desired length, for
example l metre to 1000 metres.
The flexible material may be micro-perforated to permit the egress
of liquid from the tube but not the egress of the particulate filler
15 material.
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The particulate filler material which is used to fill the
compartments may be any suitable particulate material such as sand,
cement, crushed stone, a particulate-containing sludge or slurry
such as a mine sludge or slurry, mine tailings, fly ash, river bed
20 sediment, or bentonite or other clays or the like.
In addition, some or all of the compartments may include a rigid
filler item such as a wood, cement or metal pillar or prop. The
area around the pillar or prop in a compartment is then filled with
the particulate filler material. Such a pillar or prop serves to
25 provide rigidity to the support member especially before all the
compartments have been filled with the particulate material.
Each restraining means illustrated in Figure 1 of the drawings, run
only a part of the length of the tube. However, restraining means
may be used which runs the whole of the length of the tube. The
restraining means illustrated in Figure 1 is a plastic or metal
5 tape. However, the restraining means may also comprise weld mesh,
diamond mesh, fencing wire, plastic netting, or a plastic mesh such
as that covered by South African Patent No. 82/7300 or a plastic
metal or rope.
It is not necessary to use restraining means. In particular, it is
10 not necessary to use restraining means where the ratio of the
diameter of the support member to the height of the support member
is sufficiently great. For example, where the diameter or width of
the support member is 8 times the height of the support member, no
restraining means will generally be required.
15 As a further alternative, to obviate the need for restraining means,
the compartments around the circumference of the tube may be left
empty. This provides additional restraint against deformation in a
direction transverse to the longitudinal axis of the tube.
The support member gains its great strength under an a~ial
20 compressive load because of the fact that most or all of the
compartments are adjacent two or more other compartments which are
also filled with the particulate filler material. This prevents the
compartments from rupturing as they are simultaneously supported by
their neighbours and provide support to their neighbours.
25 The support member may be used as a support in an underground mine
as illustrated in the drawings to support a hanging wall in the same
manner that a conventional mat pack is used. The support member may
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also be used in the construction industry as a load-carrying support
member. For example, it may be used in the construction of
buildings or as a support for a bridge or the like. It may also be
used to form ballast for a railway line, in which case the support
5 will generally be between 0, 5M and lm in height.
The support member of the invention has several advantages.
Firstly, it is easy and cheap to manufacture. Secondly, it may be
assembled on site, e.g. down a mine, which has considerable
logistical advantages. For example, the empty tube divided into
10 compartments may be folded up and easily transported down the mine.
There it may be placed in position and then filled with a
particulate filler material which is available on site. Thirdly,
the support member is able to bear high compressive loads.
