[0001] The present invention relates to a process for consolidation of soils and/or building
structures in contact with soils, as well as a relevant device used in said process.
[0002] The soils, but also the building structures of civil, industrial or monumental buildings,
as well as the building structures consisting of retaining walls of embankments or
slopes, may be ravelled, in particular as a result of ground failures or seismic events,
which may cause instability and damages, even serious ones, to the relevant building
structures.
[0003] The consolidation of said soils and of the building structures in contact with them,
which may also be performed by way of prevention (in particular, antiseismic prevention),
is traditionally performed in two ways:
- through the so-called micropiles, reinforced with steel pipes, having such a length
as to allow a suitable (according to the indications inferred from on-site surveys
and from a geotechnical site characterization) underlying soil to be reached. The
use of micropiles normally involves the use of extremely bulky machinery and the accomplishment
of significantly invasive excavations and also entails the accomplishment of reinforced
concrete curbs connecting the micropile heads.
- through the reclamation of the existing soil by injecting polyurethane resins or eco-friendly
expansive cement mortars allowing the soil to be consolidated, however with limited
results, which may be insufficient.
[0004] Italian patent
IT 1383319 and
EP-A1-1719841 describe a process for consolidating building structures and the relevant device
to implement said process, basically combining the micropile technology with soil
consolidation through expanding substances. In particular, the process consists of:
producing at least one hole having a first section which extends in the building structure
and a second section which extends in the adjacent soil;
inserting into each hole a reinforcement which extends in both the first section and
the second section;
injecting at least in the second section, between the reinforcement and the wall of
each hole, an expanding resin which, once cured, is adapted to consolidate the soil
and to constrain the reinforcement thereto.
[0005] However,
IT 1383319 also provides the possibility to constrain the reinforcement in each hole to the
building structure by injecting in said first section of the hole, according to a
particular technique, a fluid other than said resin and suitable to harden after curing.
[0006] In this manner, micropiles are implemented in particular under the foundations of
a building structure and, in addition, the soil around each micropile and more generally
under the building structure is consolidated, all this in order to make sure that
the underlying soil and the overall building structure are consolidated as desired.
[0007] However, the solution offered by
IT 1383319 has some drawbacks. In particular, once the above hole has been drilled, in yielding
soils it may turn out hard or even impossible to insert the relevant reinforcement
in the hole, because the soil surrounding the hole collapses, clogging it.
[0008] Furthermore, it is necessary to have availability of two different machine-tools,
namely a drill and a machine for injecting the expanding resin.
[0009] The present invention sets the goal to implement a process for consolidation of soils
and, if present, also of the building structures in contact with said soils, as well
as a device usable in said process, so that the drawbacks described above do not arise.
[0010] Said goal is achieved and the relevant technical problem is solved by the consolidation
process and the relevant device disclosed in the appended claims.
[0011] The invention will be more easily understandable from the following description of
a form of embodiment of the process and device according to the invention. In said
description reference will be made to the appended drawings, wherein:
fig. 1 is a side view of a form of embodiment of the device according to the invention,
to be used for implementing a process according to the invention, the process allowing
soils and/or building structures in contact with said soils to be consolidated;
fig. 2 is an enlarged view of one of the sleeves which are a part of the device of
fig. 1;
fig. 3 is a side view of the same sleeve as shown in fig. 2, but rotated by 90° degrees
around its own axis;
fig. 4 is a top view thereof;
fig. 5 is an axial cross-section according to the dashed line 5-5 of fig. 3;
fig. 6 is a cross-section thereof according to the dashed line 6-6 of fig. 5;
fig. 7 shows the device of fig. 1 as mounted in situ as a result of the implementation
of the process according to the invention, the device having been used to consolidate
a soil having a level surface;
fig. 8 shows the use of several devices according to the invention for consolidating
the soil underlying a mat foundation of a building structure, the devices being constrained
to said foundation;
fig. 9 shows the use of devices such as those of fig. 1 for consolidating a stone
building structure of a traditional type as well as the underlying soil;
fig. 10 shows how it possible to consolidate the soil under a traditional stone building
structure and at the same time to constrain the device according to the invention
to said structure without any drilling concerning the building structure directly;
fig. 11 shows an alternative way to connect a traditional stone building structure
with the devices according to the invention;
fig. 12 shows how it is possible to consolidate an embankment and the relevant building
structure consisting of a traditional stone containment wall;
fig. 13 shows how it is possible to consolidate and contain an embankment or a slope.
[0012] Examining fig. 1 it can be seen that the device 10 comprises a series of conventional
self-drilling hollow bars 12 (in the specific case three bars, marked with 12.1, 12.2
and 12.3), made of steel (such as S 355 steel or a steel with enhanced performance),
of the type with improved adhesion, the side surface of said bars having a helical
rib allowing a connection to be made between them through sleeves 14, the enlargement
of one of which is shown in figures 2-6.
[0013] As can be seen in particular in figures 5 and 6, the sleeve 14 is internally threaded
so that the corresponding ends of two consecutive bars 12 can be screwed thereinto,
implementing the connection between the two bars 12. In particular, fig. 6 shows that
the two hollow bars 12 which are screwed to refusal into the sleeve 14 do not reach
the through side openings 16 obtained in the sleeve 14 in diametrically opposed positions.
It should be remarked that the number of openings 16 can be other than two (although
the availability of two openings arranged like openings 16 is preferential) and the
openings can even not be lying on the same transverse plane, their number ranging
from a single opening to a number not far higher than two, for obvious reasons. The
openings 16, if more than one, are conveniently arranged at an angle and are equally
spaced. Check valves (non shown for the sake of simplicity), opening when a certain
pressure is achieved inside the sleeve, are inserted in the openings 16.
[0014] Again with reference to fig. 1, it can be seen that a conventional single-use drill
bit 18 is fastened in a conventional way to the lower end of the bar 12.1. The assembly
formed by the self-drilling bars 12.1, 12.2 and 12.3, by the two connecting sleeves
14 and by the drill bit 18 forms a drill rod 10 which is used, by means of special
machines, in the process according to the present invention.
[0015] The length of the drill rod 10 can be varied within certain ranges, using an appropriate
number of bars 12 and sleeves 14, the bars being available on the market in different
lengths and diameters. In particular, bars of the self-drilling type having an outer
diameter of 32 mm, 38 mm and 51 mm, respectively, and a thickness of 5.2 mm for 32
and 38 mm bars and a thickness 9.4 mm for 51 mm bars can be retrieved.
[0016] The connecting sleeves 14, preferably made of S 355 steel or a steel with enhanced
features, are made so as to be adapted to the diameter of the bars 12 which must be
connected.
[0017] The two through openings 16 provided in the sleeves 14 have in this specific case
a diameter of 16 mm. The relevant check valves (as pointed out, not shown for the
sake of simplicity) are conveniently of the type applicable by pressing them into
the relevant openings 16 and can be set, for example, to 10 bar or to 20 bar opening
or to other pressure values, depending on the requirements.
[0018] As regards the single-use drill bits 18, they are retrievable on the market as kits
for the aforesaid self-drilling bars and they can be provided with bits for holes
in the rock or in walls, or else they can be three-blade drilling bits for drilling
in soils of any nature. Said single-use bits are provided with through openings allowing
the environment outside the bit and the inside of the hollow drill rod 10 to communicate
with each other.
[0019] The hole which is obtained by drilling with drill rods 10 provided with the drill
bits 18 has a diameter ranging from 60 to 100 mm, depending on the diameter of the
bar 12 and hence of the drill bit 18 in use.
[0020] Some applications of the process and of the device according to the present invention
will now be described, referring to figures 7-14.
[0021] The drill rod 10 represented in fig. 1 can be used to simply consolidate the soil,
for example the soil marked with 20 in fig. 7. In this case, after accurate geotechnical
surveys, a design will be drafted, providing a certain number of drillings with drill
rods 10 of a certain length and consisting of a certain number of self-drilling bars
12, having a certain diameter and a suitable single-use drilling bit 18.
[0022] Once a drilling to reach the desired depth (for example to reach a soil layer with
better features or to have an anchorage of sufficient length) has been made and once
the relevant hole has accordingly been bored in the soil 20, the drill rod 10 is left
in the hole, so as to act as reinforcement.
[0023] Through an injection pipe 19 connected with the outer end of the drill-reinforcement
rod 10, an expanding fluid substance (for example a proper polyurethane resin of the
type used for consolidating soils, or else a mortar based on expanding cement, of
the type which is already used for this purpose) is now injected inside the latter.
The injection occurs at a pressure which causes the opening of the check valves provided
in the openings 16 of the sleeves 14, so that the expanding substance flows out of
the openings 16 and out of the openings (not shown) which are present in the bit 18,
fills the hole portion which is not occupied by the drill rod 10 and also infiltrates
the surrounding soil. Once said expanding substance is cured, the situation is as
represented in fig. 7, wherein the area marked as a whole with 21 is the soil portion
concerned by said substance one expanded, so that the soil is consolidated on account
of the presence of the above expanded substance and of the relevant reinforcement
consisting of the drill rod 10.
[0024] Repeating the above process for the required number of times, a soil with any surface
extension may be consolidated.
[0025] The process according to the present invention can also be used to consolidate a
soil on which a building structure is already existing (in particular, a pre-existing
building structure in a seismic area), which is in its turn consolidated. Fig. 8 shows
a building structure 22.1 (represented very schematically), in particular a reinforced
concrete structure, whose foundation 24.1 rests on the soil 20.
[0026] Using such a process as described above with reference to fig. 7, it is possible
to achieve the situation represented in fig. 8, wherein the soil 20 under the foundation
24.1 is consolidated through the use of a series of drill-reinforcement rods 10 and
relevant soil areas 21 concerned by the expanding substance, but in this case the
drilling also concerns the building structure 22.1 and in particular its foundation
24.1, a ring gasket 26 fitted on each drill rod 10 prevents the expanding fluid substance
from climbing again to the hole beyond said gasket and the hole section remaining
free from the drill rod 10 above the gasket 26 is injected, through a second injection
pipe 23, with a fluid substance (for example an epoxy mortar with large-size gravel
and/or rapid-setting, shrink-proof rheoplastic mortar), thus implementing a connecting
means, marked with 27, adapted to make the relevant section of the drill-reinforcement
rod 10 integral with the foundation 24.1 of the structure 22.1.
[0027] Fig. 9 represents a situation wherein the drill-reinforcement rods 10 are also constrained
to the building structure 22.2, which is of the traditional type made of stone, and
in particular to its foundation 24.2, since the drilling has been performed through
said foundation as well. Highlighting that identical or similar elements in figures
8 and 9 have been marked with the same reference numbers (this applies also to the
remaining figures), it should be remarked that in fig. 9 the two visible drill-reinforcement
rods 10, to be regarded as not lying on the same vertical plane, have an opposed tilting
and might belong to a sequence of rod pairs such as the one in fig. 9, a sequence
which concerns the whole length of the structure 22.2 perpendicularly to the sheet
plane.
[0028] Fig. 10 represents a building structure 22.2 similar to the one of fig. 9, the only
difference being that the two drill-reinforcement rods 10 do not cross the building
structure and are inserted directly into the soil (as is the case of fig. 7), but
are slightly tilted in the opposite direction and with one of the two rods 10 (the
one on the right) being connected to the building structure 22.2 by a connecting means,
marked as a whole with 27.1, comprising a section of the steel L-profile 30.1, which
is connected both to the relevant rod 10 by a special threaded sleeve 28 and to the
building structure 22.2 through screws 29 conventionally inserted in the foundation
of the building structure 22.2.
[0029] Fig. 11 represents another situation wherein the two drill-reinforcement rods 10,
in this case arranged vertically, do not cross the stone building structure 22.2:
they are both connected to the structure 22.2 by a connecting means, marked as a whole
with 27.2, comprising a metal profile 30.2 arranged across the foundation of the building
structure 22.2 and buried in a concrete casting, with the two ends of the profile
30.2 being welded to the head of the relevant rods 10 and embodied in their respective
reinforced concrete grade beams extending parallel to the foundation of the building
structure 22.2 and containing the same.
[0030] Fig. 12 shows how the process and the device according to the present invention allow
an embankment 20 supported by a building structure 22.3 consisting of a traditional
stone containment wall to be consolidated. The drill-reinforcement rod 10 inserted
into the embankment crosses also the wall 22.3 and is connected thereto by the connecting
means 27 used in figures 8 and 9; however, a steel match plate 33 fastened to the
rod 10 by a threaded sleeve 28 similar to the one used in fig. 10 to fasten the rod
10 to the L-profile 30 is also provided. Obviously, in the case of fig. 12 several
drill-reinforcement rods 10 might be provided and the containment wall might be made
of reinforced concrete instead of stone.
[0031] Fig. 13 illustrates the case wherein an embankment 20 (originating for example from
excavations), not supported by a containment wall, is stabilised by means of the drill-reinforcement
rods 10, whose outer end is fastened to plates 33 such as those of figures 12 and
13, the plates matching an electrowelded steel net 34, between the latter and the
embankment a geonetwork 35 being available to prevent the embankment from collapsing.
[0032] As can be understood from the foregoing, the process and the device according to
the present invention are usable for consolidation of soils and/or building structures
in the most varied situations and are adjustable to the specific requirements which
may arise, particularly for the consolidation of soils and building structures existing
in seismic areas, but also simply for the consolidation of soils (for example liquefied
as a result of an earthquake) and/or for increasing the load-carrying capacity thereof
in view of the construction of new building structures upon them.
[0033] It is also highlighted that in order to implement the process according to the present
invention a single machine-tool can be used to perform both the drilling and the injection.
1. Process for consolidating soils (20) and/or building structures (22) in contact with
these soils, comprising the following steps:
- producing in the soil (20) to be consolidated, by means of drilling, at least one
hole using a drill rod (10) with a drill bit (18) of single use type, the drill rod
(10) comprising several hollow drill bars (12) arranged consecutively and connected
to one another by means of coaxial sleeves (14) to obtain a rotating coupling that
allows drilling, at least one of the sleeves (14) being provided with at least one
lateral through opening (16) that places the inside of the sleeve (14) in communication
with the outside, this opening (16) being closed by a check valve adapted to open
when the pressure inside the sleeve (14) exceeds a predetermined value;
- leaving the drill rod (10) in the hole bored in the soil, so as to act as reinforcement;
- injecting into the drill rod (10), through the outer end thereof, at a pressure
that causes opening of the check valves provided in the holes (16) of the sleeves
(14), an expanding substance adapted, once cured, to consolidate the surrounding soil
and to constrain thereto the drill rod (10) acting as reinforcement.
2. Process according to claim 1, wherein the expanding substance is a two-component polyurethane
resin having this characteristic.
3. Process according to claim 1, wherein the expanding substance is a premixed cement-based
mortar having this characteristic.
4. Process according to claim 1, wherein, if a building structure (22) is present on
the soil (20) to be consolidated, there are provided means (27) to connect the outermost
length of the drill rod (10) left in situ with a part of the building structure (22).
5. Process according to claim 4, wherein the means (27) for connecting the outermost
length of the drill rod (10) with a part of the building structure (22) are obtained
by boring, by means of the same drill rod (10), a first part of the hole in the building
structure (22), and then inserting into the first part of the hole, between the drill
rod (10) left in situ and the wall of the hole, an annular gasket (26) that, when
injection is carried out, prevents the expanding resin from rising substantially into
the first part of the hole that involves the building structure (22), the drill rod
(10) not having the aforesaid sleeves (14) provided with check valves in the first
part of the hole;
subsequently, after the expanding substance has been injected, injecting into the
hole bored in the structure, between drill rod (10) and wall of this hole, a fluid
substance adapted to unify the related length of the drill rod (10) with the building
structure (22).
6. Process according to claim 5, wherein the fluid substance adapted to unify the related
length of the drill rod with the building structure (22) is an epoxy mortar and/or
a quick setting shrinkage-compensated rheoplastic mortar.
7. Process according to claim 4, wherein the means for connecting the outermost length
of the drill rod with the part of the building structure comprise metal elements (30)
and/or reinforced concrete elements (31) fastened both to the outermost length of
the drill rod (10) and to the building structure (22).
8. Device for consolidating soils (20) and/or building structures (22) in contact with
these soils, consisting of a drill rod (10) comprising several hollow drill bars (12)
arranged consecutively and connected to one another by means of coaxial sleeves (14)
to obtain a rotating coupling between the bars (12) that allows drilling, at least
one of the sleeves (14) being provided with at least one lateral through opening (16)
that places the inside of the sleeve (14) in communication with the outside, this
opening (16) being closed by a check valve adapted to open when the pressure inside
the sleeve (14) exceeds a predetermined value.
9. Device according to claim 8, wherein the drill bars (12) are of the self-drilling
type with external helical ribs, the sleeves (14) being internally threaded so that
the related end of the corresponding bar (12) can be screwed, for a given length,
until the end of its travel, into each of the two ends of the sleeves (14).
10. Device according to claim 8, wherein the drill bars (10) and the connecting sleeves
(14) are made of S355 steel.
1. Ein Verfahren zur Verfestigung von Böden (20) und/oder Baustrukturen (22), welche
sich in Berührung mit diesen Böden befinden, das jeweils folgende Schritte umfasst:
- Das Herstellen von mindestens einer Bohröffnung durch Bohren in dem Boden (20),
der verfestigt werden soll, wobei ein Bohrgestänge (10) mit einer Einwegbohrspitze
(18) verwendet wird und das Bohrgestänge (10) mehrere hohle Bohrstangen (12) umfasst,
welche jeweils hintereinander angeordnet und miteinander mit Hilfe von koaxialen Hülsen
(14) verbunden sind, um eine Drehkupplung zu erzielen, welche das Bohren gestattet,
wobei mindestens eine der Hülsen (14) jeweils mit mindestens einer seitlichen durchgehenden
Öffnung (16) versehen ist, die das Innere der Hülse (14) jeweils mit der Außenseite
in Verbindung bringt, wobei diese Öffnung (16) durch ein Rückschlagventil geschlossen
wird, das geeignet ist, sich jedes Mal dann zu öffnen, wenn der Druck im Innern der
Hülse (14) einen vorbestimmten Wert überschreitet;
- das Zurücklassen des Bohrgestänges (10) in der in den Boden gebohrten Bohröffnung,
so dass es als Verstärkung fungiert;
- das Einspritzen in das Bohrgestänge (10), und zwar durch dessen äußeres Ende und
bei einem Druck, welcher das Öffnen des in den Öffnungen (16) der Hülsen (14) vorgesehenen
Rückschlagventils verursacht, einer Expansionssubstanz, die geeignet ist, nach entsprechender
Aushärtung den Umgebungsboden zu verfestigen und das Bohrgestänge (10), welches als
Verstärkung fungiert, darin zu verankern.
2. Ein Verfahren gemäß Anspruch 1, wobei die Expansionssubstanz ein Bikomponenten-Polyurethanharz
ist, welches diese Eigenschaft aufweist.
3. Ein Verfahren gemäß Anspruch 1, wobei die Expansionssubstanz ein vorgemischter zementhaltiger
Mörtel ist, welcher diese Eigenschaft aufweist.
4. Ein Verfahren gemäß Anspruch 1, wobei, wenn eine Baustruktur (22) auf dem Boden (20)
vorhanden ist, welcher verfestigt werden soll, jeweils Elemente (27) vorgesehen sind,
um die äußerste Länge des Bohrgestänges (10), das in situ belassen wird, jeweils mit
einem Teil der Baustruktur (22) zu verbinden.
5. Ein Verfahren gemäß Anspruch 4, wobei die Elemente (27) zur Verbindung der äußersten
Länge des Bohrgestänges (10) mit einem Teil der Baustruktur (22) durch Bohren eines
ersten Teils der Öffnung in der Baustruktur (22) mit Hilfe des selben Bohrgestänges
(10) erzielt werden, und dann durch Einsetzen in den ersten Teil der Öffnung, zwischen
das in situ belassene Bohrgestänge (10) und die Wand der Öffnung, einer ringförmigen
Dichtung (26), welche nach Durchführung der Einspritzung das Expansionsharz im wesentlichen
daran hindert, in den ersten Teil der Öffnung zu steigen, der die Baustruktur (22)
involviert, wobei das Bohrgestänge (10) nicht die zuvor erwähnten Hülsen (14) mit
den entsprechenden Rückschlagventilen im ersten Teil der Öffnung aufweist;
anschließend, nachdem die Expansionssubstanz eingespritzt wurde, durch Einspritzen
in die in die Struktur gebohrte Öffnung zwischen dem Bohrgestänge (10) und der Wand
dieser Öffnung, einer flüssigen Substanz, welche geeignet ist, die entsprechende Länge
des Bohrgestänges (10) jeweils mit der Baustruktur (22) zu verbinden.
6. Ein Verfahren gemäß Anspruch 5, wobei die flüssige Substanz, welche geeignet ist,
die entsprechende Länge des Bohrgestänges mit der Baustruktur (22) zu verbinden, ein
Expoxy-Mörtel und/oder ein rheoplastischer, schnellhärtender, schrumpfkompensierter
Mörtel ist.
7. Ein Verfahren gemäß Anspruch 4, wobei die Elemente zur Verbindung der äußersten Länge
des Bohrgestänges mit dem Teil der Baustruktur Metallelemente (30) und/oder verstärkte
Betonelemente (31) umfassen, welche beide jeweils an der äußersten Länge des Bohrgestänges
(10) und an der Baustruktur (22) befestigt sind.
8. Eine Vorrichtung zur Verfestigung von Böden (20) und/oder Baustrukturen (22), welche
sich in Berührung mit diesen Böden befinden, die aus einem Bohrgestänge (10) besteht,
das mehrere hohle Bohrstangen (12) umfasst, die jeweils hintereinander angeordnet
und miteinander mit Hilfe von koaxialen Hülsen (14) verbunden sind, um eine Drehkupplung
zwischen den Stangen (12) zu erzielen, welche das Bohren gestattet, wobei mindestens
eine der Hülsen (14) jeweils mit mindestens einer seitlichen durchgehenden Öffnung
(16) versehen ist, welche das Innere der Hülse (14) mit der Außenseite in Verbindung
bringt, und diese Öffnung (16) durch ein Rückschlagventil geschlossen wird, das geeignet
ist, sich zu öffnen, wenn der Druck im Innern der Hülse (14) einen vorbestimmten Wert
überschreitet.
9. Eine Vorrichtung gemäß Anspruch 8, wobei die Bohrstangen (12) vom selbstbohrenden
Typ mit äußeren schraubenförmigen Rippen sind und die Hülsen (14) innen ein Gewinde
aufweisen, so dass das entsprechende Ende der jeweiligen Stange (12) über eine bestimmte
Länge und bis zum Ende seines Wegs in jedes der beiden Enden der Hülsen (14) eingeschraubt
werden kann.
10. Eine Vorrichtung gemäß Anspruch 8, wobei das Bohrgestänge (10) und die Verbindungshülsen
(14) aus S355 Stahl bestehen.
1. Procédé de consolidation de sols (20) et/ou de structures de construction (22) en
contact avec ces sols, comprenant les étapes suivantes :
- l'exécution dans le sol (20) à consolider, par forage, d'au moins un trou en utilisant
une tige de forage (10) avec un outil de forage (18) d'un type à usage unique, la
tige de forage (10) comprenant plusieurs barres de forage creuses (12) agencées consécutivement
et reliées l'une à l'autre au moyen de manchons coaxiaux (14) pour obtenir un accouplement
tournant qui permet le forage, au moins un des manchons (14) étant pourvu d'au moins
une ouverture passante latérale (16) qui met l'intérieur du manchon (14) en communication
avec l'extérieur, cette ouverture (16) étant fermée par un clapet de non retour adapté
pour s'ouvrir quand la pression à l'intérieur du manchon (14) dépasse une valeur prédéterminée
;
- le fait de laisser la tige de forage (10) dans le trou foré dans le sol, de manière
à servir de renforcement ;
- l'injection dans la tige de forage (10), à travers son extrémité extérieure, à une
pression qui provoque l'ouverture des clapets de non retour dans les trous (16) des
manchons (14), d'une substance expansible adaptée, une fois durcie, pour consolider
le sol environnant et pour fixé à celui-ci la tige de forage (10) agissant comme un
renforcement.
2. Procédé selon la revendication 1, dans lequel la substance expansible est une résine
de polyuréthane à deux composants ayant cette caractéristique.
3. Procédé selon la revendication 1, dans lequel la substance expansible est un mortier
à base de ciment pré-mélangé ayant cette caractéristique.
4. Procédé selon la revendication 1, dans lequel, si une structure de construction (22)
est présente sur le sol (20) à consolider, il est prévu des moyens (27) pour connecter
le tronçon le plus externe de la tige de forage (10) laissée en place comme une partie
de la structure de construction (22).
5. Procédé selon la revendication 4, dans lequel les moyens (27) pour connecter le tronçon
le plus externe de la tige de forage (10) avec une partie de la structure de construction
(22) sont obtenus en forant, au moyen de la même tige de forage (10), une première
partie du trou dans la structure de construction (22), et en insérant ensuite la première
partie du trou, entre la tige de forage (10) laissée en place et la paroi du trou,
une garniture annulaire (26) qui, quand l'injection est exécutée, empêche la résine
expansible de monter sensiblement dans la première partie du trou qui concerne la
structure de construction (22), la tige de forage (10) n'ayant pas les manchons précités
(14) munis de clapets de non retour dans la première partie du trou ;
successivement, après que la substance expansible a été injectée, l'injection dans
le trou foré dans la structure, entre la tige de forage (10) et la paroi de ce trou,
d'une substance fluide adaptée pour unir le tronçon correspondant de la tige de forage
(10) à la structure de construction (22).
6. Procédé selon la revendication 5, dans lequel la substance fluide adaptée pour unir
le tronçon correspondant de la tige de forage à la structure de construction (22)
est un mortier époxy et/ou un mortier rhéoplastique à retrait compensé à prise rapide.
7. Procédé selon la revendication 4, dans lequel les moyens pour connecter le tronçon
le plus externe de la tige de forage avec la partie de la structure de construction
comprend des éléments métalliques (30) et/ou des éléments en béton armé (31) fixés
à la fois au tronçon le plus externe de la tige de forage (10) et à la structure de
construction (22).
8. Dispositif pour la consolidation de sols (20) et/ou de structures de construction
(22) en contact avec ces sols, comprenant une tige de forage (10) comprenant plusieurs
barres de forage creuses (12) agencées consécutivement et reliées l'une à l'autre
au moyen de manchons coaxiaux (14) pour obtenir un accouplement tournant entre les
barres (12) qui permet le forage, au moins un des manchons (14) étant pourvu d'au
moins une ouverture passante latérale (16) qui met l'intérieur du manchon (14) en
communication avec l'extérieur, cette ouverture (16) étant fermée par un clapet de
non retour adapté pour s'ouvrir quand la pression à l'intérieur du manchon (14) dépasse
une valeur prédéterminée.
9. Dispositif selon la revendication 8, dans lequel les barres de forage (12) sont du
type auto-perceur avec des nervures hélicoïdales externes, les manchons (14) étant
profilés intérieurement de manière que l'extrémité correspondante de la barre correspondante
(12) puisse être vissée, sur une longueur donnée, jusqu'à la fin de sa course, dans
chacune des deux extrémités des manchons (14).
10. Dispositif selon la revendication 8, dans lequel les barres de forage (10) et les
manchons de raccordement (14) sont réalisés en acier S355.