WO2011073545A1

WO2011073545A1 - Device for anchoring in multilayer ground

Info

Publication number: WO2011073545A1
Application number: PCT/FR2010/052031
Authority: WO
Inventors: Christian Meline
Original assignee: Ancrest S.A.
Priority date: 2009-12-16
Filing date: 2010-09-28
Publication date: 2011-06-23
Also published as: EP2513378B1; EP2513378A1

Abstract

The invention relates to an anchoring device wherein a positioning plate (5), intended for bearing on the ground surface, is mounted onto a hollow rod (2). The rod consecutively supports, from the positioning plate (5) to the free end (22), at least one helical force disk (6) then one helical penetration disk (8). Said anchoring device is characterized in that the rod extends after the helical penetration disk opposite the plate (5). Said anchoring device is moreover characterized in that a bit (4) is placed on the free end of said rod so that a first portion of the rod (2), capable of being screwed into at least one first ground layer, extends from the plate (5) to the helical penetration disk and moreover so that a second portion of the rod (2), capable of being anchored in a second ground layer, extends from the helical penetration disk (8) to the bit (4).

Description

Anchoring device in a multilayer floor.

The present invention relates to an anchoring device in a multilayer floor, of the type comprising a hollow rod whose first end receives means of fasteners and whose opposite end free is intended to penetrate into the ground.

Two types of anchoring devices are known, each adapted to anchors in specific soils. The anchoring, whether terrestrial or maritime, of buildings or structures may indeed be to be carried out in loose soil or floors of greater hardness. Thus, in the case of loose soil, screw anchoring devices comprising one or more mounted helical discs welded to a rod are provided. These anchors screw can stabilize the structure to anchor, since the thickness of the first layer of loose soil is sufficient.

In addition to this first problem related to the environment in which this type of device must be used, another disadvantage is that this type of screw anchor device can not be used in layers of hard floors. In the case of these hard floors, self-drilling anchoring devices are provided, in which the rod is provided at its end with a cutter capable of digging the soil and whose size greater than the diameter of the rod makes it possible to create a cavity. in which is injected cement to secure the anchoring with the ground. Such a self-drilling device however has the disadvantage of not adapting to soils of lesser hardness.

Now, the anchoring structure can be made to be made in a soil of variable hardness, composed from the surface of a first layer of loose soil, then a second monolithic layer. The use of one or other of the devices mentioned above can not allow a satisfactory anchoring of the structure. The first layer of loose soil is of insufficient thickness to stabilize a screw anchor, and the use of a self-drilling anchor is made impossible by the depth to which the second layer extends, the distance to the surface likely to destabilize the self-drilling anchor.

In addition, the self-drilling capacity of the anchoring devices used until now may be insufficient, particularly in some granulometry and varied mineral structure, compacted by the pressure of water and also in some terrestrial soils of clay-limestone nature or composed of serious with hydraulic catch, presenting compactness close to monolithic soils.

The present invention aims to provide an anchoring device that allows a solid anchoring in soils of variable thickness and / or different hardness, as mentioned above.

For this purpose, the invention proposes an anchoring device in a multilayer floor, of the type comprising a hollow rod whose first end receives fastening means and whose opposite end free is intended to penetrate into the ground, in a positioning plate is mounted on the hollow rod and is intended to bear on the ground surface, the rod carrying successively from the positioning plate towards the free end at least one helical force disk and a helical disk of penetration, characterized in that the rod extends after the helical disc penetration opposite the positioning plate, and in that a cutting is disposed at the free end of this rod, so that first part of the rod extends from the positioning plate to the helical penetration disk, this first part being able to be screwed into at least a first layer of soil, and so that a second part of the rod extends from the helical penetration disc to the cutter, this second part being able to be anchored in a second layer of soil.

Such a device allows a strong structure anchoring, the first part of the rod being intended to be screwed into a first layer of soil, for example furniture, which extends over a second layer of a soil for example monolithic and consolidated rocky type, harder than the first layer of soil, and in which the second part of the stem is able to be anchored.

According to various features of the present invention:

the cutter has a diameter greater than the diameter of the rod;

the at least one helical force disk and the helical penetration disk are welded to the rod;

a cylindrical envelope is formed around the first part of the rod, between the positioning plate and the helical disk of effort closest to the plate; a cylindrical envelope is formed around the first part of the rod, between the positioning plate and the helical penetration disk,

the cylindrical casing has a variable diameter whose smallest diameter is greater than the diameter of the second part of the stem,

the cylindrical envelope comprises a first section extending from the positioning plate and having a first diameter followed by a second section extending to the helical penetration disk and having a second diameter smaller than the first diameter and greater than diameter of the second part of the stem,

the hollow stem is threaded or smooth,

the hollow rod is threaded on at least the second portion extending between the helical penetration disc and the cutter, and in that this hollow rod is smooth in the first part surrounded by the cylindrical envelope;

- At least a portion of the rod and the cutter are drilled with holes for the injection of a cement or a synthetic resin for anchoring in compact soils of rock type;

the holes for cement injection are drilled only on the second part of the rod and on the cutting edge,

the holes for the injection of cement or resin are drilled on the first part and the second part of the rod and on the cutting edge,

the at least one helical force disk has an outside diameter greater than the outside diameter of the helical penetration disk,

the hollow rod carries between the at least one helical helical disk and the helical penetration disk at least one intermediate helical disk of outside diameter between the outside diameters of the helical disks, respectively of force and penetration,

said at least one intermediate helical disc is formed by a discontinuous spiral, and

said at least one intermediate helical disk is formed by a continuous conical spiral connecting the helical disks.

The invention will now be described in more detail but in a nonlimiting manner with reference to the appended figures and in which: - Figure 1 is a schematic representation of an anchoring device according to a first embodiment of the invention;

FIG. 2 is a schematic representation of an anchoring device according to a second embodiment of the invention;

FIG. 3 is a schematic representation of an anchoring device according to a third embodiment of the invention;

FIG. 4 is a schematic representation of an anchoring device according to a fourth embodiment of the invention,

FIG. 5 is a schematic representation of an anchoring device according to a fifth embodiment of the invention,

FIG. 6 is a schematic representation of an anchoring device according to a sixth embodiment of the invention,

FIG. 7 is a schematic representation of an anchoring device according to a seventh embodiment of the invention,

FIG. 8 is a schematic representation of an anchoring device according to an eighth embodiment of the invention, and

- Figure 9 is a schematic representation of an anchoring device according to a ninth embodiment of the invention.

The anchoring device according to the invention, as shown in all the figures, comprises a hollow rod 2, a first end 21 of which receives attachment means, not shown, of a structure or a building to anchoring in the ground, the opposite end free 22 of the hollow rod 2 being for this purpose intended to penetrate into the ground. This structure is brought to be fixed relative to the ground, whether in a land or sea application.

This anchoring device is of particular interest in the case of an anchoring ground formed of several layers of distinct compositions, and in particular a floor as shown in FIGS. 1 and 2, in which a first layer 31 is formed of a thickness of loose material, for example sand, chippings and generally unconsolidated materials, this first layer 31 resting on a second layer 32 formed of rocks, limestones or concretes end urcis and materials in general monolithic or consolidated, or in the case of a soil shown in FIGS. 3 and 4, in which a third layer 33, formed of vases, rests on this first layer 31.

For this purpose, the rod 2 has, at a determined distance from the ends, a helical penetration disk 8, a first portion 23 of the rod 2 extending between the first fastening end 21 and this helical penetration disk 8, while a second portion 24 of the rod 2 extends between the helical penetration disk 8 and the free end 22 of drilling. The first portion 23 of the rod 2 is, as shown in the figures, adapted to be screwed at least in the first layer of soil 31, and the second portion 24 of the rod 2 is adapted to be anchored, by drilling of the end of the rod 2, in the second layer of soil 32.

A positioning plate 5 is mounted on the hollow rod 2 and is intended to bear on the ground surface, while the helical penetration disk 8 is disposed on the rod 2 at a determined length of this positioning plate 5 so that the helical penetration disk 8 rests on the upper part of the second layer of harder soil 32. A soil analysis prior to drilling makes it possible to determine the size of the first layer of soil 31, and thus to determine at what distance from the positioning plate 5 the helical penetration disk 8 must be arranged on the rod 2.

Depending on the application and the type of ground in which the anchoring device is used, the positioning plate 5 is not necessary for example for anchoring in underwater soils.

The first portion 23 of the rod 2 comprises at least one helical disk 6 effort whose function is to penetrate by screwing in the first layer of loose soil 31. Depending on the thickness of the loose soil layer, it may be provided several helical disks force 6. The number of helical disks to be provided on the rod 2 depends on the density of the soil in which the rod must be anchored. The increase in the number of helical force disks increases the anchoring effort of the device. Thus, the lower the density of the soil, the higher the number of force disks must be. The diameter of the selected discs is determined to avoid that torques of recovery efforts are too important. The distance between two helical disks force 6 depends on the diameter of the disks. This distance between two disks is between two and five times the diameter of the disk, and advantageously between three and four times this diameter.

The helical disks force 6 extend over the first portion 23 of the rod 2, between the helical penetration disk 8 and the positioning plate 5. So that the helical disks effort 6 are in engagement with the first layer from the ground 31, the diameter of the helical penetration disk 8, brought to penetrate the ground before the helical disks of force 6, must be equal to or smaller than the diameters of the helical disks of effort 6. It has been represented, on all the figures, helical disks force 6 diameter equivalent to each other, it will be understood that in accordance with what has been written above, the diameters of each helical disk effort 6 could vary, from when a reduction in the diameter of the helical disks force 6 is respected, the helical disk effort 6 closest to the positioning plate 5 to the helical disk 6 effort closest to the disq These helicoidal force disks 6 may advantageously have an incoming portion of beveled primer and reinforced by a filler metal. Like the hollow rod 2, these helicoidal disks 6 and penetration 8 can be made of high-strength steel. The spiral disks 6 and penetration force 8 are welded to the rod 2.

According to a feature of the present invention, the rod 2 extends in a second portion 24, after the helical penetration disk 8 opposite the positioning plate 5. A cutting 4 is disposed at the free end 22 of This rod 2 This self-drilling cutter 4 is welded or screwed at the end of the rod 2, and has the rigidity characteristics necessary to be able to drill in a second layer of soil 32, made of consolidated or monolithic material. The second portion 24 of the rod 2 will thus participate in fixing the structure by anchoring in the ground, following the drilling performed by the cutter 4. The length of the second portion 24 of the rod 2 is then chosen to achieve this anchoring over a sufficient length to stabilize the anchoring device. According to an embodiment not shown, a connecting sleeve can be used to increase the total length of the rod and thus the depth of penetration into the ground. Such a device allows a strong structure anchoring, the first portion 23 of the rod 2 being intended to be screwed into at least a first layer of loose soil 31, which extends over a second layer 32 of a monolithic soil and consolidated , harder than the first layer of soil 31, and wherein the second portion 24 of the rod 2 is adapted to be anchored. The drill end of the rod, provided with the cutter, initially digs the first layer of loose soil, and shapes a borehole which facilitates the screwing action of the helical discs penetration and effort in this first layer.

The cutter 4 disposed at the free end of the rod 2 has a diameter greater than the diameter of the second portion 24 of the rod 2. The drilling of the ground by the cutter 4 then generates a cavity 12 in which extends to following the cutting 4, the second portion 24 of the rod 2. In order to anchor the rod 2 in the ground, an injection of cement or synthetic resin is performed in this cavity 12 (Figures 1 to 5) to maintain in position the rod 2 relative to at least the second layer of soil 32. For this purpose, at least a portion of the rod 2 and the cutter 4 are pierced with holes, not shown, for injection.

This cement or this resin can be injected on a greater or lesser part of the rod 2 of the anchoring device. In a first embodiment shown in Figure 1, only the second portion 24 of the rod 2 and the cutter 4 are pierced with injection holes.

In a second embodiment shown in Figure 2, the assembly of the rod 2 and the cutter 4 are pierced with injection holes, so that the cement or the resin is spread around the entire rod 2 , in the cavity 12 formed by the cutter 4 for the second portion 24 of the rod 2, and in an additional cavity 1 1 formed by the helical penetration disk 8 and the helical disks force 6 for the first part 23 of the stem 2.

The choice of use of an anchoring device according to one or other of the embodiments mentioned above is in particular made by the thicknesses of the different layers of each floor. If the first soil layer 31 and the third soil layer 33 require that the first portion 23 of the rod 2 be of a large size, it may be considered preferable for the stability of the anchor to perform a cement injection on the entire stem 2. However, the composition of the third soil layer 33, made of vases, makes it impossible to inject cement or resin around the first portion 23 of the rod 2 which extends into this third layer. The additional cavity 1 1 formed by the passage of the helical penetration disk 8 in the third soil layer 33 is recapped immediately after the passage of the helical penetration disk 8. This may also be the case in the first layer of soil 31, in particular if this layer is composed of sand.

In order to provide a space in which the resin or the injected cement can be inserted, as illustrated by FIGS. 3 and 4, a cylindrical envelope 20 is formed around the first part 23 of the rod 2. The envelope 20 is extends between the positioning plate 5 and the helical disk effort 6 closest to this plate, and rests against the plate 5 and this disk. Thus, after the passage of the discs, the loose material forming the third layer of soil 33 can not fill the additional cavity 1 1 formed by the discs 6 and 8, and a cement injection can be made between the rod 2 and the Cylindrical shell 20. It should be noted that, in one embodiment not shown, the envelope 20 may be provided between two helical disks force 6 to allow injection of cement around the rod in the first thickness of soil 31 .

According to a variant, the cylindrical envelope 20 is formed around the first portion 23 of the rod 2, between the positioning plate 5 and the helical penetration disk 8.

In a fifth embodiment shown in FIG. 5, a cylindrical casing 40 is formed around the first portion 23 of the rod 2 between the positioning plate 5 and the helical penetration disk 8 and this casing 40 has a variable diameter.

In general, the variable diameter of the cylindrical envelope 40 varies between a large diameter and a small diameter which is greater than the diameter of the second portion 24 of the rod 2.

As shown in FIG. 5, the cylindrical envelope 40 comprises a first section 41 extending from the positioning plate 5 and having a first diameter d1 followed by a second section 42 extending to the helical penetration disk 8 and having a second diameter d2 less than first diameter d1 and greater than the diameter d3 of the second portion 24 of the rod 2.

In this embodiment also, at least a portion of the rod 2 and the cutter 4 are pierced with holes for the injection of a cement or a synthetic resin.

Thus, according to various embodiments, only the portion of the rod 2 located between the helical penetration disk 8 and the cutter 4 is pierced with holes for the injection of cement or resin or only the portion of the rod 2 located between the last helical drive disk 6 and the helical penetration disk 8 is pierced with holes for the injection of a cement or a synthetic resin.

According to yet another embodiment, the holes for the injection of cement or synthetic resin are drilled over the entire length of the second portion 24 of the rod 2 and on the cutter 4.

As shown in FIG. 5, holes are also drilled on the first portion 23 of the rod 2 for filling with cement or synthetic resin chambers inside the casing 40. This filling increases the strength of the envelope and allows also eliminate any internal corrosion.

The sections 41 and 42 of the cylindrical envelope 40 are welded together and they support helical disks force 6. The hollow rod 23 threaded or smooth form the main resistance column and allows all types of attachment in the upper part as well as the connections with a device for injecting cement or synthetic resin.

Referring now to FIGS. 6 to 9, other embodiments of the anchoring device according to the invention will be described.

In these figures, the elements common to the previous embodiments are designated by the same references.

The anchoring device shown in these figures has a higher self-drilling capacity than the devices previously described and it can be used in particular in certain underwater soils, of varying grain size and mineral structure, compacted by the pressure of water and also in some Terrestrial soils of clay-limestone nature or composed of gravels with hydraulic grip, presenting compactness close to monolithic soils.

In Figures 6 and 7, the anchoring device is formed by a hollow rod 2 threaded along its entire length between the two ends 21 and 22. The end 22 of the rod 2 is provided with a cutting 4. The disc helicoidal force 6 closest to the cutter 4 has an outer diameter greater than the outer diameter of the helical disc penetration 8.

The rod 2 carries in its second portion 24 between the helical disk 6 effort closest to the cutter 4 and the helical disk penetration 8 at least one helical disk 50 intermediate outer diameter between the outer diameters of the helical disks, respectively of effort 6 and penetration 8.

According to the embodiment shown in FIG. 6, the intermediate helical disk 50 is formed by at least one discontinuous spiral 51 welded to the rod 2.

According to one variant, a plurality of discontinuous spirals 51 may be interposed in the space delimited by the helical force disk 6 and the helical penetration disk 8, these discontinuous spirals being interposed in a variable or constant pitch and the diameter of these discontinuous spirals. being inscribed in a frustoconical envelope whose large base is the diameter of the helical disk of force 6 and the small base, the diameter of the helical disc of penetration 8.

According to another embodiment shown in FIG. 7, the intermediate helical disk 50 is formed by a conical spiral 52 continuous connecting the helical disks, respectively of force 6 and penetration 8. This continuous spiral 52 is inscribed in a frustoconical envelope whose large base is determined by the outer diameter of the helical force disk 6 and the small base is determined by the outer diameter of the helical penetration disk 8.

According to the embodiments shown in Figures 8 and 9, a cylindrical casing 40 having a variable diameter and disposed around the first portion 23 of the rod 2 and the helical disk effort 6 closest to the cutting 4. This cylindrical envelope 40 is identical to that described for the embodiment shown in Figure 5.

In these embodiments, the helical force disk 6 closest to the cutter 4 also has an outside diameter greater than the outside diameter of the helical penetration disk 8 and the rod 2 carries between this helical disk 6 and this drive disk helical helix 8 at least one intermediate helical disc 50 of outer diameter between the outer diameters of the helical disks, respectively of force 6 and penetration 8.

In FIG. 8, said at least one intermediate helical disk 50 is formed by a discontinuous spiral 51 identical to the discontinuous spiral of the embodiment shown in FIG. 6. In FIG. 9, said at least one intermediate helical disk is formed by a continuous conical spiral 52 continues identical to that of the embodiment shown in FIG. 7.

As shown in the figures, the hollow rod 2 forming the anchoring device has a constant diameter over the entire length of the anchoring device. It will be understood that a rod 2 of constant diameter allows simplified industrialization of the anchoring device, but could be replaced in one variant by a rod of variable diameter. By way of nonlimiting example, the diameter of the parts of the rod 2 not covered with a cylindrical envelope 20 or 40 could be greater than the diameter of the parts of the rod surrounded by said envelope 20 or 40. These variations in diameter of the rod must however allow the realization of the characteristics mentioned above, namely in particular that the cutter 4 must have a diameter greater than the diameter of the second portion 24 of the rod 2.

Similarly, there is shown in the figures a hollow rod 2 threaded. It will be understood that this rod can be threaded or smooth, and for example have a mixed profile. For example, the rod 2 may be threaded on the second portion 24 extending between the penetration disc 8 and the cutter 4, and this rod 2 may be smooth in the portion 23 surrounded by the cylindrical envelope 20 or 40.

Such an anchoring device allows the fixation of structure or building in soils with layers of different compositions. The anchoring device is put in place by screwing using a rotary hammer, supported by a drill arm or by a submerged installation according to the terrestrial application or Navy envisaged. The device can then extend in these successive layers in a strictly vertical manner as shown, or with a different orientation without departing from the context of the invention, since the cutting edge and the second part of the rod are anchored in a second layer of monolithic or consolidated soil, or furniture, and since this second layer is covered with at least a first layer of loose soil, and that the first part of the stem and the associated disks are screwed into at least the first layer of loose soil.

Such a mixed anchoring device, combining the characteristics of anchoring by drilling and screwing, by means of a single rod, makes it possible to take into account in a single device all the anchoring forces, to know the efforts of extraction and bending on the one hand, and compression and buckling on the other hand.

The mixed anchoring device according to the invention is able to withstand various stresses and mainly bending forces by reinforcing the upper diameter of the rod 2. The bending forces are generated by variable forces with an orientation between 0 and 90 °.

Claims

1. - Anchoring device in a multilayered soil comprising a hollow rod (2), a first end (21) of which receives fastening means and whose opposite free end (22) is intended to penetrate into the ground, in which a positioning plate (5) is mounted on the hollow rod (2) and is intended to bear on the ground surface, the rod carrying successively from the positioning plate (5) to the free end (22) at least one helical force disk (6) and a helical penetration disk (8), characterized in that the rod extends after the helical penetration disk (8) opposite the positioning plate (5), and in that a cutter (4) is arranged at the free end of this rod, so that a first portion (23) of the rod (2) extends from the positioning plate (5) to the helical disc penetration (8), this first part (23) being able to be screwed into at least one e first layer of soil (31), and so that a second portion (24) of the rod (2) extends from the helical penetration disk (8) to the cutting edge (4), this second portion (24) being adapted to be anchored in a second layer of soil (32).

2. - Anchoring device according to claim 1, characterized in that the cutter (4) has a diameter greater than the diameter of the second portion (24) of the rod (2).

3. An anchoring device according to claim 1 or 2, characterized in that the at least one helical force disc (6) and the helical penetration disk (8) are welded to the rod (2).

4. - anchoring device according to claim 1, characterized in that a cylindrical casing (20) is formed around the first portion (23) of the rod (2), between the positioning plate (5) and the helical effort disk (6) closest to this plate (5).

5. - Anchoring device according to claim 1, characterized in that a cylindrical casing (20, 40) is formed around the first portion (23) of the rod (2), between the positioning plate (5) and the helical penetration disc (8).

6. - anchoring device according to claim 5, characterized in that the cylindrical casing (40) has a variable diameter, the smallest diameter is greater than the diameter of the second portion (24) of the rod (2).

7. - Anchoring device according to claim 6, characterized in that the cylindrical envelope (40) comprises a first section (41) extending from the positioning plate (5) and having a first diameter followed by a second section (42) extending to the helical penetration disk (8) and having a second diameter smaller than the first diameter and greater than the diameter of the second portion (24) of the rod (2).

8. - Anchoring device according to any one of claims 4 to 7, characterized in that the hollow rod (2) is threaded or smooth.

9. - Anchoring device according to any one of claims 4 to 7, characterized in that the hollow rod (2) is threaded on at least the second part

(24) extending between the helical penetration disc (8) and the cutter (4), and in that said hollow rod (2) is smooth in the first part (23) surrounded by the cylindrical envelope (20, 40).

10. Anchoring device according to one of the preceding claims, characterized in that at least a portion of the rod (2) and the cutter (4) are pierced with holes for the injection of a cement or a synthetic resin for anchoring in compact soils of the rock type.

1 1. - Anchoring device according to claim 10, characterized in that the holes for the injection of cement or resin are drilled only on the second portion (24) of the rod (2) and on the cutter (4).

12. - Anchoring device according to claim 10, characterized in that the holes for the injection of cement or resin are drilled on the first portion (23) and the second portion (24) of the rod (2) and on the cutting edge (4).

13. - Anchoring device according to any one of the preceding claims, characterized in that the at least one helical drive disk (6) has an outer diameter greater than the outer diameter of the helical penetration disk (8).

14. - Anchoring device according to any one of the preceding claims, characterized in that the hollow rod (2) carries between the at least one helical drive disk (6) and the helical penetration disk (8) at minus one intermediate helical disc (50) of outer diameter between the outer diameters of the helical disks, respectively of force (6) and penetration (8).

15. - Anchoring device according to claim 14, characterized in that said at least one intermediate helical disc (50) is formed by a discontinuous spiral (51).

16. - anchoring device according to claim 14, characterized in that said at least one intermediate helical disc (50) is formed by a conical spiral (52) continuous connecting the helical disks, respectively of effort (6) and of penetration (8).