Note: Descriptions are shown in the official language in which they were submitted.
This inven-tion :relates to pu~lic works or similar
operations in the private sec-tor.
The main oblec-t is to produce a device which makes
it possible to pass a settable -fluid product, such as a grout
material that may be cement grou-t, under a prede-termined
pressure~ as often as desired, at any intervals of time, into
a space or void which .i.s not di.rectly access.ible, such as the
annular space between a plece oE tubln~ and a drllled hole, the
earth foundatlons a:E a construction, etc~ In other words, such
injections of grout ma-terlal in the llquld state are made at
locations where it ls usually expected that voids will develop
in or about such cons-truction works. The device of the invention
may be i.nstalled during the constructlon of a work which is
known to eventually have -to be treated, or installed by drilling
or boring.
Hitherto, such injections have been carried out by
means of a simple plunger tube, possibly provided with a non-
return valve, which generally only enables a single treatment
to be carried out since the setting of the product clogs up the
pipes when a settable product is being used unless the product
is driven out by water or slurry. This can be disadvantageous
since the liquid used for driving out then flows into -the
volume to be treated and can disrupt the product put in place.
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Such injections have also been carried out by means
of a device wlt~ a double shutter fixed at the end of a more or
less rigid in~ectio~ tube, which requires: straight pipes in
whlch the double shutter can slide; a pipe diameter which is
large enough to protect both an injection tube with sufficient
section, -taking into account the desi~ed flowt and any other
tubing necessary for the operatiol~ o;~ the device with the double
shutter; the performance of operations which are oEten delica-te,
with risk of the device with the double shutter becomin~ jammed
in the pipe; and surface equipment which is often substantial,
comprising, for example, a hoist.
Furthermore, the pressure at injection level cannot
be controlled unless additional costly equipment is used,
because of the uncertainty of the amount of pressure lost in
the pipes.
There is accordingly claimed herein essentially a
device allowing the repeated injection of a grout material in
liquid state into a volume to be treated, comprising valving
means, pumping means for pumping the grout material to said
valving means through a first tubing element, and a valve
device for varying the pressure in a second tubing element con-
nected downstream of said valving means, said valving means
being constructed to open to the volume to be treated only when
the pressure of the grout material e~ceeds a given minimum
value.
These tubing elements or pipes can have a small
diameter and may be flexible or ri~id, and can allow any course
determined by the limitations of the position and obstructions
on
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the site.
The pipes can be ~ashed, without unwanted
liquids passing into the volume to be -treated, by using
a washlng pressure which is insuf~icient to open the
shutter.
It is therefore possible to repeat the operation
as many times as desired, even after several hours or
several years, without having to use heavy equipment
(such as a hoist) but simply some flexible tubing.
The following description, which refers to the
attached drawings given as non-limiting examples, explains
how the invention is put into practice.
In the drawings:
Figure 1 is a diagrammatic view of a simple
embodiment of the device which is the subject of the
invention.
Figures 2 to 10 sho~ diagrammatically some
applications of the invention as follows:
For cementing a post or tube (Figures 2 and 3);
For treatment ~mder a dam (Figure 4);
For underpinning beneath foundations (Figure 5);
For work on a tunnel (Figure 6);
For repairing the joints of a retaining wall
(Figure 7); and
For various operations relating to marine
platforms (Figures 8 to 10),
In the embodiment shown in Figure 19 the device
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essen-tially comprises: a tubing element 1, for example a
U-tube, although its precise shape does no-t effect its
efficiency when it is placed at the level of the volume
to be -treated; and a v~lving means ~ on ~he element l,
which opens under pressure and can either connect the
interior of the elemen-t 1 -to -the ex-terior space (open
position, under pressure), or allow the liquid to flow
through -the element 1 as through a normal tube (closed
posi-tion, low pressure). This means 2 may comprise, for
example, a sleeve 20 made of rubber or similar resilien-tly
flexible material fixed to the outside of the tube 1,
placed around -the latter at the desired tension and
covering a part of the tube which has holes 10 drilled in
it. If the downstream circui-t is closed, the pressuris-
ation of the liquid in the tube 1 dilates the sleeve andthe liquid flows ou-t. If, on the other hand9 the down-
stream circuit is open and the flow is weak, the sleeve
remains flat against the tube, and the liquid flows into
the tube 1 to escape through the downstream circuit. It
should be noted that this type of means 2 allows the
downstream and upstream circuits to be reversed.
The element 1 is connected to the working area
by two pipes which can be flexible or rigid and comprising
a downstream pipe 3, and an upstream pipe 4 connected to
a unit 5 for pumping the trea-tment liquid.
In the pipe 3, in the working area there are
provided a device 6 for indicating the pressure (for
example a manometer) and a valve device such as a tap 7
5 --
A manometer ~, or any other device for measuring
pressure, Gan also be provided in the pipe 4, for example
at the outlet of the pumping unit.
The pipes can be put in position in varlous ways,
some examples of which are given in the following
paragraphs.
Before each operation 9 the pipes are washed by
passing the washing liquid (wa-ter or slurry, for example)
-through the upstream pipe 4 under low pressure, the tap 7
being open and the valving means 2 remaining closed.
After washing, the tap 7 is closed and pressure
is increased, which opens the means 2 and allows the
functioning of -the device to be checked before starting
the injection. The upstream flow is immediately stopped
and the tap 7 opened, so as to decrease the pressure in
the pipes 9 which has the effect of making the means 2
close again. Thus the washing liquid does no-t flow into
the volume to be treated.
The tap 7 is kept open and the washing liquid
is driven out at low pressure (so as not to open the valving
means 2) by the treatment liquid, ~hen the treatment
liquid reaches the means 2, which is determined by
knowing the volume of the pipes and the volume despatched
by means of a flow measuring instrument a-t the pump or
measurement at the ou-tlet of the tap 7), this tap is
closed, the pressure increases, the means 2 opens and
the treatment liquid flows into the volu~eto be treated.
At the end of the operation, the pipes are
washed agaln r still without pollu-tin~ the treated volume.
The same operation can be performed as many times as
desired, that is if a void de~elops again after a first
injection in the -treated zone~ It is then sufficient to inject
grout material at a pressure sufficient to cause burs-ting of
the previous grout ~aterial that may have se-t around the valving
means. This is possible since, by defillition, a void has
developed in the valving means area.
The knowled~e o the upper and lower pressures makes
10 it possible to know the exac-t pressure in the pipe at the level
~f the injection point' if this control is not required, the
devices 6 and 8 can be omit-ted.
The precise choice of technological components does
not effect the principle of operation of the system.
It is, of course, possible to have as many double
pipe systems plus valving means as injection levels. However,
it can be advantageous in certain cases to limit -the number of
pipes.
Below each valving means 2, a non-return valve can
20 be placed which opens at very low pressure, slightly less than
that at which the means 2 open, and thus connects several return
pipes, as is shown as an example in Figure 2, where the pipe 4
is connected to two branches or first tubing elements ~a and
4b which respectively feed elements la and lb whose return pipes
or second tubing elements 3a and 3b are fitted with respective
non-re-turn valves 9a and 9b placed upstream of their connection
to the common re-turn pipe 3.
The invention is capable of use in numerous applica-
tions, some non-limiting examples of which are given below.
For cementing a post or metal tubing into a
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drilled hole 11 (Figures 2 and 3) 9 -the device can be
fixed on to the -tubing 12 before the tubing is lowered,
the pipes being placed on the inside or outside of -the
tubing, -the valve or valves 2 being on the outside of
the tubing.
I-t is also possible for the plpes to be extendeà
into the annular space which surrounds -the tubing or post,
or into a hole drilled for this purpose, before or after
the positioning of the -tubing or post.
It is thus possible to fill the annular space
with cement, as shown at 1 in Figure 3, to complete the
contact between the base of the post and the ground
surrounding it, and/or to inject the product into the
latter so as to obtain a good quality of cement around
the post and a reinforcement with the same geotechnical
characteristics as the earth, or to treat a particular
layer with any product.
This makes it possible in particular to under-
prop concrete posts which are too short (Figure 3, case
II), or to treat a layer of earth, for e~ample near to a
foundation post (Figure 3, case III).
In the case of a dam 13, by using the device
according to the inven-tion -the dam can be secured to the
ground 14, as shown at IV in Figure 4, by using the unit
1, 2 under the barrage, or an impervious screen can be
formed or reinforced under the dam~ as shown at ~ also
in Figure 4.
Figure 5 shows how underpinning beneath the
foundations of a struc-ture l~ can be carrled out, either by
inserting the device into a hole 15 drilled and imperviously
sealed in 16 around the pipes 3 and 4, or by installing the
device before constructing the foundations, as shown at VI.
Regarding the impervious sealing at 16, it is obvious that it
can be achieved in any manner known to the man of -the art.
One can imagine a plu~ made oE cement or yet an inflatable
shutter but it is obvious that none of tl~ese solutions are
actually limitative to the present invention and do not Eo.rm
part of the present invention since, in any event, the same
sealing problem was present in the prior art devices~
Figure 6 illustrates the use of the device according
to the invention to the adherence of the arch 16 of a tunnel,
where the devices l, 2 are for eventual use, placed behind the
arch before it is concreted so as to simply ensure adherence
(VII) or also that cracked areas are treated (VIII).
The invention can also be applied to the repairing
of joints in a retaining wall 18 or in a similar type o~ wall
(Figure 7), of a dam, etc., -the device being positioned before
the wall is construct~d or before the bank is filled up.
The invention also makes it possible to obtain a
distribution of pressure (Figure 8) so as to avoid deformation
of the base 19, Eor example in a metal marine structure 23
(IX) in Fi~ure 8, or to counteract e~cessive sinking, whether
differential or not (X on the same Figure).
The inventlon can also be used for dislodging a
structurc, for example i.n recoverin~ gravity platforms 21,
that is platforms resting on the sea bed (Figure 9), by
injecting a liquid under pressure underneath the said structure
at one or several points, if possible appropriately dis-tribruted
points under the structure, between the structure and the bed
on which it rests.
It is also possible to strai~hte~ a structure, for
example a marine platEor~l 21, by maklng injectlons ùnder
pressure into one or several sections defined hy projections
22 beneath the struc-ture, as shown in Figure 10~
In e~ery case, the pipes can be pvsitioned, for
eventual use, by following any rou-te (before construction,
before rapairin~r etc) or they can be installed in a hole
drilled just before treatment, the upper par-t oE this hole
being blocked up by concretin~ or by the first injection.
It goes withou-t saying that the described embodiments
are given only by way of example and that they could be
modified, in particular by substi-tuting equivalent techniques,
without exceeding -the limitations of this invention.
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