EP1878833B1 - Mixing tool for treating a portion of soil - Google Patents

Description

The present invention relates to the field of tools for treating a portion of soil in particular to improve the mechanical and / or physical characteristics.

The present invention relates more particularly to a mixing tool for the treatment of a portion of soil, said tool being in particular intended to be inserted into a tubular structure for its introduction into the soil portion.

By tubular structure is meant a structure having a cavity suitable for the passage of the mixing tool, for example a tube, a borehole or any other structure suitable for this purpose.

The document EP 1 630 299 describes a mixing tool which comprises a shaft whose lower end is provided with lateral wings which are actuated by a mechanism connected to a double set of rods extending longitudinally so as to be surface-connected to motor means.

It is understood that this type of assembly is complex and expensive because it requires a double set of rods to control the mixing tool.

An object of the invention is to provide a mixing tool which substantially overcomes the disadvantages mentioned above.

• un arbre rotatif longitudinal présentant une extrémité inférieure ;
• au moins un bras rétractable fixé à l'extrémité inférieure de l'arbre rotatif, et s'étendant latéralement par rapport à la direction longitudinale de l'arbre, ledit bras présentant une position déployée et une position rétractée de telle sorte que, en position déployée, l'envergure de l'extrémité inférieure de l'outil est supérieure au diamètre de la structure tubulaire pour permettre le traitement de la portion de sol par rotation de l'arbre ; ledit au moins un bras étant apte à se déployer par rapport à l'axe de l'arbre en formant angle ouvert vers son extrémité inférieure.
• des moyens ressorts disposés entre l'arbre rotatif et le bras rétractable permettant au bras de venir en position rétractée lors de l'insertion de la partie inférieure de l'arbre dans la structure tubulaire ; et
• une conduite (32, 132) longitudinale pour l'injection d'un fluide à proximité de l'extrémité inférieure de l'arbre.

The invention achieves its object by the fact that the mixing tool comprises:

• a longitudinal rotary shaft having a lower end;
• at least one retractable arm attached to the lower end of the rotary shaft, and extending laterally with respect to the longitudinal direction of the shaft, said arm having an extended position and a retracted position such that, in position deployed, the span of the lower end of the tool is greater than the diameter of the tubular structure to allow the treatment of the soil portion by rotation of the shaft; said at least one arm being adapted to deploy relative to the axis of the shaft at an open angle towards its lower end.
• spring means disposed between the rotating shaft and the retractable arm allowing the arm to come into retracted position upon insertion of the lower portion of the shaft into the tubular structure; and
• a longitudinal duct (32, 132) for injecting a fluid near the lower end of the shaft.

The deployed position is the natural position of the retractable arm, that is to say that in the absence of any external constraint, the arm extends laterally with respect to the longitudinal direction of the shaft being separated from this last thanks to the means springs.

When the tool is inserted into the tubular structure, it is understood that the inner wall of the tubular structure acts on the arm to bring it in retracted position, that is to say towards the shaft.

Preferably, in the retracted position, the arm extends along the rotary shaft.

It is understood that the arm is adapted to move from the retracted position to the deployed position only through the action of the spring means.

Finally, it is understood that when the treatment operation is completed, the shaft is raised to the surface, and the arm is brought into the retracted position when in contact with the lower end of the tubular structure.

Thus, the arm of the mixing tool according to the present invention is able to deploy autonomously without being actuated from the surface.

An advantage of the present invention is therefore to provide a mixing tool that does not require relative mechanical movement of parts of the type rods or coaxial tubes, and does not require the use of energy type hydraulic energy.

Another advantage of the invention is to be able to carry out a mixing operation generally called "soil mixing" which consists in mixing the soil destructured by the rotation of the arm with a fluid in order to modify the characteristics of the portion of soil treated.

For the purposes of the invention, this fluid may be, for example, a reactive liquid, a slurry or a gas carrying solid particles.

In particular, a reactive liquid may be used during an in-situ depollution operation where the destructured soil is mixed with this chemical reagent by the rotation of the retractable arm.

Advantageously, the mixing tool further comprises a ring adapted to maintain said at least one arm in the retracted position when the tool is out of the tubular structure.

The ring is used in particular before inserting the tool into the tubular structure to maintain the arm in the retracted position until it is inserted into the tubular structure.

Preferably, the ring is removed as soon as the arm is inserted into the tubular structure.

Advantageously, said at least one arm extends in an axial plane of the shaft while moving away from it.

An interest is to be able to promote the deployment of the arm during the downward translation of the tool.

Advantageously, the tool according to the invention further comprises detection means for detecting when said at least one arm is in the deployed position.

It is understood that the distance between the free end of the arm and the longitudinal axis of the shaft substantially defines the radius of the treated portion of soil.

Thus, since the arm is in an intermediate position between the retracted position and the deployed position, the diameter of the treated soil portion is smaller than the diameter for which the tool is provided, as a result of which it is not it is not possible to treat the entire portion of the soil.

The detection means according to the invention make it possible to ensure that the arm is actually in its deployed position and not in an intermediate position.

Particularly advantageously, the detection means according to the invention are particularly suitable for creating a pressure drop in the pipe.

An advantage of the creation of a pressure drop lies in the fact that it is easy to detect on the surface the presence or absence of such a pressure drop, in particular by measuring the pressure of the fluid flowing in the conduct.

Thus, thanks to the present invention, it is not necessary to place sensors near the lower end of the tool to detect the correct deployment of the arm. Such sensors generally require provide passages in the shaft to bring electrical cables from the surface to the lower end of the tool to power the sensors energy. The latter solution has the particular disadvantage of being expensive and complex to implement, unlike the technical solution proposed by the present invention.

Preferably, a significant drop in pressure measured in the pipe means that the shaft is correctly deployed.

Preferably, the detection means comprise an object capable of being held in the pipe by said arm when it is in the retracted position, and released as soon as the arm is in the deployed position.

Preferably, the span of the object is slightly smaller than the diameter of the pipe so as not to close it.

Within the meaning of the invention, "the object is released" means that the object can be driven out of the pipe by the fluid flow.

It is understood that when the object is in the pipe, it opposes the flow, so that the pressure upstream of the object is substantially greater than the pressure that would exist in the absence of this object.

Thus, the pressure in the pipe measured at the surface when the arm is in the retracted position is greater than the pressure in the pipe measured at the surface when the arm is in the deployed position, whereby it is easily detected that the arm is in the extended position.

Another advantage of the use of the object is that the pressure drop measured during the release of the object is abrupt and, consequently, easily identifiable.

Another advantage is that the position applied to the object acts on the arm so as to promote its opening.

Preferably, the object is a ball having a diameter slightly less than the inside diameter of the pipe.

It is also possible, without departing from the scope of the present invention, the use of a plurality of balls, where each is released to inform a deployment of the arm.

Advantageously, the arm comprises a lug for holding the object in the pipe when the arm is in the retracted position.

It is understood that the object is positioned upstream of the lug while being retained by it while the arm is in the retracted position.

According to a first advantageous embodiment of the present invention, the arm is pivotable along an axis orthogonal to the longitudinal direction of the rotary shaft.

Preferably, the pivot axis of the arm is positioned at a distance from the axis of the shaft.

Advantageously, the spring means comprise a cylindrical spring with angular action.

The cylindrical spring comprises a cylinder portion whose axis substantially corresponds to the axis of pivoting of the arm.

It is understood that an interest of the cylindrical spring with angular action is its compactness.

Advantageously, the lower end of the shaft further comprises a transverse opening hole communicating with the pipe, and optionally a receptacle for receiving the object disposed under the through hole.

It is understood that the receptacle serves to recover the object when it is released.

Since it is in the receptacle, the object no longer constrains the pipe and the fluid can flow through the through hole.

Preferably, the hole opens on the side of the arm so that the fluid can be brought into contact with the part of the soil that has just been destructured.

Advantageously, the tool according to the first embodiment of the invention comprises at least two similar retractable arms arranged on either side of a diameter of the rotary shaft.

Preferably, the tool according to the invention comprises two similar arms arranged on either side of a diameter of the shaft.

The invention also relates to an installation comprising a mixing tool according to the invention, a tube able to be arranged beforehand in the ground and into which the mixing tool can be inserted to reach the portion of soil to be treated.

Preferably, the lower end of the tubular structure is chamfered or beveled so as to allow the progressive deployment of the tool, and its subsequent reintroduction into the tubular structure.

An advantageous application of this installation is for example to improve a portion of soil under a railway, without polluting the ballast.

Another advantageous application of this installation is for example the treatment of a portion of soil located below a platform or a roadway layer.

Another advantageous application of this installation is the treatment of a portion of soil under a masonry element or concrete such as a sole, a raft or a wall. In this application, the tubular structure will consist of a borehole made in the element that the mixing tool must cross to reach the layer to be treated.

Indeed, it is understood that with the present invention, the soil layer extending along the tubular structure is advantageously protected.

The invention also relates to a method for treating a portion of soil in which a tube is provided, a mixing tool according to the invention, in which method the tubular structure is first introduced into the soil up to the portion of the soil to be treated, the tool is inserted into the tubular structure, the tool is moved into the tubular structure until the lower end of the tool is introduced into the soil portion, and the retractable arm is deployed. and rotating the shaft while injecting a fluid into the soil portion through the lower end of the shaft, whereby the treated area is circumscribed to said portion of soil.

The invention finally relates to a method of treating a portion of soil in which a tube is provided, a mixing tool which comprises a rotary shaft having a lower end provided with mixing means deployable, method in which the tubular structure is introduced into the soil to the portion of soil to be treated, the mixing tool is inserted into the tubular structure until the mixing means are arranged in the portion of soil to be treated the mixing means are deployed, the mixing means are activated while injecting a fluid into the portion of soil to be treated, whereby the soil layer extending over the height of the tubular structure is not treated.

• la figure 1 est une vue en coupe schématisant l'insertion de l'outil selon le premier mode de réalisation de l'invention dans un tube préalablement introduit dans le sol ;
• la figure 2 montre l'outil mélangeur selon le premier mode de réalisation de l'invention dans la phase du déploiement des deux bras ;
• la figure 3 est une vue longitudinale en coupe de l'outil mélangeur selon le premier mode de réalisation de l'invention, montrant l'injection de fluide après le déploiement des bras ;

The invention will be better understood and its advantages will appear better on reading the detailed description which follows, of embodiments shown by way of non-limiting examples. The description refers to the drawings, in which:

• the figure 1 is a sectional view schematically the insertion of the tool according to the first embodiment of the invention in a tube previously introduced into the ground;
• the figure 2 shows the mixing tool according to the first embodiment of the invention in the deployment phase of the two arms;
• the figure 3 is a longitudinal sectional view of the mixing tool according to the first embodiment of the invention, showing the injection of fluid after the deployment of the arms;

The mixing tool according to the present invention is in particular but not necessarily used in the implementation of a method of soil mixing.

Soil mixing is a process of treating a portion of soil by mixing the unstructured soil with a fluid such as a grout or reagent, in order to change its mechanical, physical and / or chemical properties.

With the help of Figures 1 to 3 We will now describe in more detail the mixing tool 10 according to one embodiment of the present invention.

The figure 1 is a sectional view taken in a vertical plane showing the insertion of the mixing tool 10 in a tubular structure constituted here by a tube 12 which has been previously introduced into the ground 14.

However, there are situations in which it is not necessary to use a tube: for example when it is necessary to cross a solid layer to reach the portion of soil to be treated, it is previously carried out a borehole in the solid layer , this drilling constituting the tubular structure within the meaning of the present invention. It is therefore understood that in the latter situation, the casing of the borehole is optional.

In the remainder of the detailed description, the particular case in which the tubular structure is a tube is described.

To introduce the tube 12 into the ground 14, it is in particular possible to make a first bore in which the tube 12 is lowered .

In the example shown on the figure 1 , The tube 12 is disposed substantially horizontally but could also decide to have an inclined manner.

The mixing tool 10 is intended to treat a portion of soil 16 located at the lower end of the tube 12, the latter having been represented by the dotted lines on the figure 1 .

As we see on the figure 1 , the mixing tool comprises a longitudinal rotary shaft 18 fixed to rotation means not shown here but otherwise known.

In this example, the lower end of the rotary shaft 18 is provided with, preferentially two retractable arm similar 20,22 which are arranged on either side of a diameter of the shaft. It is understood that the arms 20,22 can destructure the soil during the rotation of the shaft.

In their retracted position represented on the figure 1 , The two arms 20,22 extend along the lower end of the shaft 18 being held in this position by a ring 24.

According to the invention, the ring 24 serves to hold the two arms 20,22 in the retracted position before the insertion of the mixing tool 10 into the tube 12.

As we see on the Figures 1 to 3 , The two arms 20,22 are pivotally mounted on the lower end of the shaft 18, around axes orthogonal to the longitudinal direction of the shaft 18, such that the arms 20,22 can extend laterally with respect to the longitudinal direction of the shaft 18.

Spring means comprising cylindrical, angularly acting springs 26, 28 are arranged between the rotary shaft 18 and each of the two retractable arms 20, 22 , so that these arms have a natural tendency to deploy with respect to the axis. of the shaft 18 thanks to the action of the springs 26,28.

Preferably, in their deployed position, the arms 20, 22 form an open angle towards the lower end of the shaft, as shown in FIG. figure 3 .

It is understood that when the lower end of the mixing tool 10 is inserted into the tube 12, the inner walls thereof hold the arms 20, 22 in an intermediate position between the retracted position and the extended position.

To do this, the inside diameter of the tube 12 is slightly greater than the span of the tool when the arms 20,22 are in the retracted position.

When the lower end of the mixing tool 10 begins to emerge from the lower end of tube 12, while being driven in a rotational movement about the axis of the shaft 18, the arms 20,22 start to deploy under the action of the springs 26,28, to then reach their deployed position shown on the figure 3 .

Preferably, the lower end of the shaft 18 further comprises a drill bit 30 forming a tip to facilitate the penetration of the mixing tool 10 in the portion of soil to be treated.

In the deployed position, as shown in the figure 3 , the span e of the lower end of the tool 10 is greater than outside diameter d of the tube 12, to allow the treatment of the portion of soil 16.

Particularly advantageously, the shaft 18 further comprises a longitudinal pipe 32 for injecting a fluid near the lower end of the shaft 18.

As we see more particularly on figures 2 and 3 , the lower end of the shaft 18 further comprises a transverse opening hole 34 communicating with the pipe 32, this hole being disposed above the drill bit 30 when the latter is present.

This opening hole 34 makes it possible to direct the flow of the fluid towards the inside of the portion of soil to be treated.

The fluid that is injected through line 32 into the portion of soil 16 to be treated may be a liquid, a reagent, a slurry, a gas carrying solid particles or any other type of fluid for treating a soil.

The mixing tool according to the invention can in particular be used to carry out an in situ soil remediation by mixing the soil destructured soil portion for example with a chemical treatment liquid.

Particularly advantageously, the mixing tool according to the invention further comprises detection means 36 for detecting when the arms 20, 22 are in the deployed position.

To do this, the detection means 36 are able to create a head loss in the pipe, this head loss being detectable on the surface by measuring the pressure of the fluid flowing in the pipe 32.

It will be understood that when a pressure drop is created locally in the pipe 32 , the pressure of the fluid upstream of the pressure drop becomes greater than that existing in the absence of the pressure drop.

In other words, the creation (or disappearance) of a pressure drop is detectable on the surface by a simple pressure measurement of the fluid.

According to the invention, it is arranged that in the retracted position, a pressure drop is created in the pipe 32, while in the deployed position, this pressure drop is eliminated.

Therefore, it is understood that with the present invention, a simple measurement of a significant drop in fluid pressure can detect the deployment of the arms 20, 22.

Preferably, the detection means 36 comprise an object, for example a ball 38, able to be held in the pipe 32 by the arms 20, 22, when they are in the retracted position, and released as soon as the arms 20 , 22 are in the deployed position.

It is not essential that the object completely closes the pipe 32, the purpose here being to create a significant loss of load. Moreover, it is advantageous to allow the injection of fluid before the deployment of the arms 20,22.

To create the pressure drop, the ball 38 preferably has a diameter slightly smaller than the internal diameter of the pipe 32.

As we see on the figures 1 and 3 , each of the two arms 20,22 comprises a lug 40,42 to maintain the ball 38 in the pipe when the arms are in the retracted position.

As we see on the figure 3 , the shaft 18 further comprises two diametrically opposite longitudinal slots 43, 43 ' , opening into the pipe 32 on the one hand, and on the outer wall of the shaft 18 on the other hand, so as to define a passage for the lugs 40,42.

The advantage of having two lugs is understood by the fact that the ball 38 is released only when the two arms 20,22 are in the deployed position. Thus, if only one of the two arms is in the deployed position, the ball 38 will still be held in the pipe by the other arm.

In other words, the detection means can detect that these two arms are actually in the deployed position.

Preferably, the lugs 40,42 are constructed such that they release the ball 38 only when the two arms are in the deployed position and not in an intermediate position.

Moreover, it is understood that the fluid pressure being applied to the ball surface 38 generates a force which is transmitted to the pins 40,42 and 20,22 to the arm leading to their deployment.

Preferably, the lower end of the shaft 18 further comprises a receptacle 44, which may be formed in the drill bit 30, to recover the ball 38 when it has been released.

According to a variant, the tool 10 does not have a receptacle and the ball 38 is lost in the ground.

The invention also relates to an installation for treating a portion of soil comprising a mixing tool 10 according to the invention, and a tubular structure 12 adapted to be arranged beforehand in the ground and into which the mixing tool 10 can be inserted. to reach the portion of soil 16 to be treated.

According to the invention, the lower end of the inner wall of the tubular structure 12 is bevelled so as to allow the progressive deployment of the arms of the mixing tool according to the embodiment, as well as the progressive retraction of the arms during the ascent of the tool.

The invention also relates to a method of treating a portion of soil in which a tubular structure is provided, such as for example a tube 12 and a mixing tool according to the invention, for example but not necessarily a tool 10, depending on the method. embodiment of the invention.

According to the invention, the tube 12 is introduced first into the soil up to the portion of soil 14 to be treated, the tool 10 is inserted , in the tube 12, the tool is moved in the tube until the lower end of the tool 10 is introduced, in the ground portion, the retractable arms 20, 22 are deployed and the rotation is effected. the shaft 18 while injecting a fluid into the soil portion by the lower end of the shaft 18 or 118, whereby the treated area is circumscribed to said portion of soil.

In other words, the soil layer situated above the soil portion 16 is advantageously protected.

An example of application is the treatment of a portion of soil under a railway track.

Thanks to the present invention, it is indeed possible to treat the portion of soil by protecting the ballast supporting the railway, through a casing extending according to the height of the ballast.

It is also possible to treat a portion of soil under a platform or under a layer of roadway.

Also, this installation makes it possible to treat a portion of soil through a masonry element or concrete, such as a sole, a raft or a wall.

In cases where a solid layer must be crossed to reach the portion of the soil to be treated, drilling is carried out in this solid layer, said drilling constituting the tubular structure within the meaning of the invention.

It is understood that in the latter case, the casing drilling is optional.

The installation according to the invention also allows an in-situ depollution by injecting a chemical treatment liquid during the destructuration of the soil by the deployed arms.

The invention also relates to a method of treating a portion of soil in which a tubular structure is provided, such as for example a tube 12 a mixing tool 10 which comprises a rotary shaft 18 having a lower end provided with deployable mixing means 20, A method in which the tube 12 is introduced into the soil up to the portion of soil to be treated, the mixing tool 10 is inserted into the tube until the mixing means are arranged in the portion of soil to be treated, the mixing means 20,22 are deployed, the mixing means are activated while injecting a fluid into the portion of soil to be treated, whereby the layer of soil extending over the height of the tube is not treated.

In this process, it is particularly advantageous to use a mixing tool such as those described above.

This method makes it possible, in particular, to treat the pollution of a portion of soil with a minimum reworking of the soil situated above the portion of soil to be treated.

Claims (16)

1. A mixing tool (10) for treating a portion of ground (16), said tool being for inserting in a tubular structure (12) in order to enable it to be introduced into the portion of ground, said tool comprising:

   · a longitudinal rotary shaft (18) presenting a bottom end;

   · a longitudinal duct (32) for injecting a fluid in the proximity of the bottom end of the shaft;

   · at least one retractable arm (20, 22) fastened to the bottom end of the rotary shaft and extending laterally relative to the longitudinal direction of the shaft, said arm (20, 22) presenting a deployed position and a retracted position in such a manner that, in the deployed position, the span of the bottom end of the tool is greater than the diameter of the tubular structure for enabling the portion of ground to be treated by rotating the shaft (18), said at least one arm (20, 22) being suitable for deploying relative to the axis of the shaft (18) by forming an angle that is open towards its bottom end;
   the tool being characterized in that it further comprises:

   · spring means (26, 28) arranged between the rotary shaft (18) and the retractable arm (20), enabling the arm to go from the retracted position to the deployed position when the bottom portion of the shaft exits from the tubular structure and enabling the arm to go back from the deployed position to the retracted position when the bottom portion of the shaft is reincorporated in the tubular structure, whereby the mixing tool is suitable for deploying and retracting in self-contained manner without being actuated from the surface.
2. A mixing tool according to claim 1, characterized in that it further comprises a ring (24) suitable for holding said at least one arm (20, 22) in the retracted position when the tool is outside the tubular structure (12).
3. A mixing tool according to claim 1 or claim 2, characterized in that said at least one arm (20, 22) extends in an axial plane of the shaft while being spaced apart therefrom.
4. A mixing tool according to any one of claims 1 to 3, characterized in that it further comprises detector means (36) for detecting that said at least one arm (20, 22) is in the deployed position.
5. A mixing tool according to claim 4, characterized in that the detector means (36) are suitable in particular for creating a loss of head in the duct (32).
6. A mixing tool according to claim 5, characterized in that the detector means include an object (38) suitable for being held in the duct by said arm (20, 22) when it is in the retracted position, and for being released as soon as the arm (20, 22) is in the deployed position.
7. A mixing tool according to claim 6, characterized in that the object is a ball (38) of diameter that is slightly less than the inside diameter of the duct (32).
8. A mixing tool according to claim 6 or claim 7, characterized in that the arm (20, 22) includes a lug (40, 42) for holding the object (38) in the duct when the arm (20, 22) is in the retracted position.
9. A mixing tool according to any one of claims 1 to 8, characterized in that the arm (20, 22) is suitable for pivoting about an axis orthogonal to the longitudinal direction of the rotary shaft (18).
10. A mixing tool according to claim 9, characterized in that the spring means (26, 28) are arranged between the movable shaft and the retractable arm and comprise a cylindrical spring (26, 28) acting angularly.
11. A mixing tool according to claim 9 or claim 10, characterized in that the bottom end of the shaft (18) is also provided with a drilling tooth (30) in the form of a spike.
12. A mixing tool according to any one of claims 9 to 11, characterized in that the bottom end of the shaft also includes a transverse through hole (34) communicating with the duct (32) and a container (44) for receiving the object arranged under the through hole.
13. A mixing tool according to any one of claims 9 to 12, characterized in that it includes at least two similar retractable arms (20, 22) arranged on either side of a diameter of the rotary shaft (18).
14. Plant for treating a portion of ground, the plant comprising a mixing tool (10) according to any one of claims 1 to 13 and a tube (12) previously arranged in the ground and into which the mixing tool is to be inserted in order to reach the portion of ground (16) to be treated.
15. A method of treating a portion of ground (16) wherein a tubular structure (12) and a mixing tool (10) according to any one of claims 1 to 13 are provided, the method comprising initially introducing the tubular structure into the ground until it reaches the portion of ground to be treated, inserting the tool in the tubular structure, moving the tool in the tubular structure until the bottom end of the tool is introduced in the portion of ground, deploying the retractable arm (20, 22), and causing the shaft (18) to rotate while injecting a fluid into the portion of ground via the bottom end of the shaft, whereby the treated zone is restricted to said portion of ground.
16. A method of treating a portion of ground according to claim 15, characterized in that when the treating operation has finished, the shaft is raised to the surface, and the arm is taken to the retracted position on coming into contact with the bottom end of the tubular structure.

Images