Mixing tool for treating a portion of soil

Abstract

A device (10) for treating a portion of soil comprises a rotary shaft (20), at least one deployable mixer tool (40) secured to the rotary shaft (20), and a longitudinal pipe (22) for injecting a fluid in the proximity of the mixer tool (40). According to the invention, the treatment device (10) further includes a boring tool (24) situated at the bottom end of the shaft (20), an outer tubular element (30) extending parallel to the rotary shaft (20), the rotary shaft (20) being arranged inside said tubular element (30), and a coupling system (50) between the rotary shaft (20) and the tubular element (30). In a first configuration, the coupling system (50) is suitable for constraining the tubular element (30) and the rotary shaft (20) to move together in rotation about the main axis (X), in at least one direction of rotation, and for constraining the tubular element (30) and the rotary shaft (20) to move together in translation along the main axis (X), at least in the downstream direction. These movements in rotation and translation can be released in a second configuration of the coupling system (50).

Claims

1. A treatment device for treating a portion of soil, the device comprising: a rotary shaft extending along a main axis and comprising a top end pointing upstream and a bottom end pointing downstream; a deployable mixer tool fastened to the rotary shaft in the vicinity of the bottom end of the rotary shaft; a longitudinal pipe configured to inject a fluid into the proximity of the bottom end of the rotary shaft; a boring tool situated at the bottom end of the rotary shaft; a tubular element extending along an axis parallel to the main axis of the rotary shaft, the rotary shaft being arranged inside said tubular element; and a coupling system coupling the rotary shaft with the tubular element, and configured to be selectively set in a first configuration and a second configuration, wherein: in the first configuration, said coupling system is configured to: constrain the tubular element and the rotary shaft to jointly move together in rotation about the main axis, in at least one direction of rotation, and constrain the tubular element and the rotary shaft to jointly move together in translation along the main axis, at least in the downstream direction, and in the second configuration, the coupling system is configured to release the tubular element and the rotary shaft from the joint movement in rotation and the joint movement in translation; wherein: in the first configuration, the deployable mixer tool is housed in the tubular element and fastened to the tubular element; and in the second configuration, the deployable mixer tool is unfastened from the tubular element and configured to radially extend from the tubular element into a portion of soil to be treated.

2. The treatment device according to claim 1, wherein the coupling system comprises a bayonet system.

3. The treatment device according to claim 2, wherein: the coupling system comprises at least one lug formed on the inside face of the tubular element and a corresponding number of catches formed on the rotary shaft, wherein: in the first configuration, the at least one lug is configured to come into abutment radially and axially against a catch, and in the second configuration, the at least one lug is configured to release from the catch.

4. The treatment device according to claim 1, wherein the deployable mixer tool comprises at least one deployable mixer arm fastened to the bottom end of the rotary shaft and configured to: in the first configuration, be retained in a retracted position by the housing; and in the second configuration, extend laterally relative to the main direction of the shaft, such that a span of the mixer tool is greater than the outside diameter of the tubular element to enable the portion of soil to be treated by rotating the shaft.

5. The treatment device according to claim 4, wherein the mixer tool further comprises a spring configured to: extend the mixer arm to from the tubular element, and retract the mixer are to the retracted position while the bottom portion of the shaft is housed in the tubular element.

6. The treatment device according to claim 1, wherein the coupling system is configured to constrain the tubular element and the rotary shaft to move together in rotation about the main axis in both clockwise and anticlockwise directions of rotation.

7. The treatment device according to claim 1, wherein the coupling system is also adapted to constrain the tubular element and the rotary shaft to move together in translation along the main axis in the upstream direction.

8. The treatment device according to claim 7, wherein the coupling system further includes an abutment adapted to co-operate with the rotary shaft so that the rotary shaft and the tubular element are constrained to move together in translation in the upstream direction regardless of the angular position of the rotary shaft.

9. A treatment device for treating a portion of soil, the device comprising: a rotary shaft extending along a main axis and presenting a top end pointing upstream and a bottom end pointing downstream; at least one deployable mixer tool fastened to the rotary shaft in the vicinity of its bottom end; a longitudinal pipe for injecting a fluid into the proximity of the bottom end of the rotary shaft; a boring tool situated at the bottom end of the shaft; an outer tubular element extending along an axis parallel to the main axis of the rotary shaft, the rotary shaft being arranged inside said tubular element; and a coupling system between the rotary shaft and the tubular element, said coupling system being suitable in a first configuration for constraining the tubular element and the rotary shaft to move together in rotation about the main axis, in at least one direction of rotation, and for constraining the tubular element and the rotary shaft to move together in translation along the main axis, at least in the downstream direction, and said coupling system being suitable in a second configuration for releasing said movement in rotation and in translation; wherein the deployable mixer tool is housed in the tubular element when the coupling system is in the first configuration; wherein the deployable mixer tool is adapted to be extracted and extended radially from the tubular element and to be introduced into a portion of soil to be treated when the coupling systems is in the second configuration, wherein the coupling system further includes an abutment adapted to co-operate with the rotary shaft so that the rotary shaft and the tubular element are constrained to move together in translation in the upstream direction regardless of the angular position of the rotary shaft, and wherein the abutment comprises a collar formed on the inside face of the tubular element, the inside diameter of said collar being smaller than the maximum diameter of the rotary shaft on the portion of said shaft that is situated downstream from said collar.

10. The treatment device according to claim 1, including at least two mixer devices that are spaced apart axially along the main axis.

11. A treatment device for treating a portion of soil, the device comprising: a rotary shaft extending along a main axis and presenting a top end pointing upstream and a bottom end pointing downstream; at least one deployable mixer tool fastened to the rotary shaft in the vicinity of its bottom end; a longitudinal pipe for injecting a fluid into the proximity of the bottom end of the rotary shaft; a boring tool situated at the bottom end of the shaft; an outer tubular element extending along an axis parallel to the main axis of the rotary shaft, the rotary shaft being arranged inside said tubular element; and a coupling system between the rotary shaft and the tubular element, said coupling system being suitable in a first configuration for constraining the tubular element and the rotary shaft to move together in rotation about the main axis, in at least one direction of rotation, and for constraining the tubular element and the rotary shaft to move together in translation along the main axis, at least in the downstream direction, and said coupling system being suitable in a second configuration for releasing said movement in rotation and in translation; wherein the deployable mixer tool is housed in the tubular element when the coupling system is in the first configuration; wherein the deployable mixer tool is adapted to be extracted and extended radially from the tubular element and to be introduced into a portion of soil to be treated when the coupling systems is in the second configuration, and wherein the coupling system is provided in the vicinity of the bottom end of the rotary shaft and of the tubular element.

12. A method of treating a portion of soil, wherein the treatment device according to claim 1 is provided, said method comprising: constraining the tubular element and the rotary shaft to move together by bringing the coupling system into its first configuration; lowering the rotary shaft into the soil together with the tubular element until reaching the portion of soil to be treated; unconstraining the rotary shaft and the tubular element by bringing the coupling system into its second configuration; moving the rotary shaft relative to the tubular element until the mixer tool is inserted into the portion of soil for treatment; deploying the mixer tool; and rotating the shaft while injecting a fluid into the portion of soil via the longitudinal pipe, whereby the portion of soil is mixed with said fluid.

13. The method of treating a portion of soil according to claim 12, wherein, after the portion of soil has been treated, the tubular element is extracted from the soil together with the rotary shaft.

14. The method of treating a portion of soil according to claim 12, wherein the injected fluid is a depolluting agent.

15. The method of treating a portion of soil according to claim 12, wherein the injected fluid is a hydraulic binder.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention can be better understood on reading the following description of an embodiment of the invention given by way of non-limiting example, and with reference to the accompanying drawings, in which:

(2) FIG. 1 is a section view of a treatment device in an embodiment of the invention, the coupling system being in its first configuration;

(3) FIG. 2 is a section view on A-A of FIG. 1;

(4) FIG. 3 is a section view on B-B of FIG. 1;

(5) FIGS. 4 and 5 are fragmentary views, respectively an elevation view and a perspective view of the rotary shaft of FIG. 1, showing a portion of the coupling system;

(6) FIGS. 6 and 7 are fragmentary views of the tubular element, respectively in perspective and in section, showing a complementary portion of the coupling system;

(7) FIG. 8 is a fragmentary and exploded view of the coupling system;

(8) FIGS. 9A to 9F show successive steps of a method of treating a portion of soil in an implementation of the invention;

(9) FIGS. 10A to 10F show steps of assembling a treatment device in an embodiment of the invention, in which the rotary shaft is a string of rods and the tubular element is a string of tubes;

(10) FIGS. 11A and 11B show a coupling system suitable for use in a treatment device in a second embodiment of the invention; and

(11) FIG. 12 shows the operation of the coupling system of FIGS. 11A and 11B in greater detail.

(12) FIG. 1 is a section view on a vertical plane showing a treatment device 10 of the invention, for treating a portion of soil defined from a depth P below the ground surface S. With reference to FIG. 9A, which shows a first step of the treatment method of the invention performed by means of said device 10, the portion of soil for treatment is given reference ST.

(13) In the example, the device 10 is moved vertically for vertical boring. It is also possible to use the device 10 to perform horizontal boring or to perform boring on a slope.

(14) As can be seen in FIG. 1, the treatment device 10 has a longitudinal rotary shaft 20 of main axis X fastened to rotary drive means (not shown but known from elsewhere), and also to a hollow elongate element or external tubular element 30, in particular a tube, which in this example is coaxial with the rotary shaft 20 and surrounds it.

(15) The treatment device 10 described in this example is used for performing a soil mixing method.

(16) Soil mixing is a method that consists in treating a portion of soil by mixing the soil that has been broken up with a fluid, such as a slip or a reagent, in order to change its mechanical, physical, and/or chemical properties thereof.

(17) In the example shown, the rotary shaft 20 has a boring tool 24 at its bottom end, e.g. a three-blade drill bit, for boring the soil so as to allow the device 10 advance.

(18) Furthermore, a longitudinal pipe 22 passes through the rotary shaft in order to inject a fluid of the above-mentioned type in the proximity of the bottom end 28 of the shaft 20. In the example, the longitudinal pipe 22 passes through the boring tool 28 and opens out via an injection orifice 23 situated at the bottom end of said tool.

(19) The outer tubular element 30 also has cutter teeth 39 at its bottom end 38.

(20) When the portion of soil for treatment ST is deep underground, the rotary shaft 20 may be made up of a succession of rods that are screwed to one another. Likewise, the tubular element 30 may be in the form of a string of tubes.

(21) In the example, and as described in greater detail below, both the rotary shaft 20 and the tubular element 30 are made up of respective assemblies, each of a plurality of successive segments, the segments being assembled together by screw fastening.

(22) In the vicinity of its bottom end, the shaft 20 is provided with a deployable mixer tool 40 that comprises, in this example, two similar arms 42 arranged diametrically opposite each other on either side of the shaft 20.

(23) When the deployable tool 40 is in the tubular element 30, as shown in FIGS. 9A to 9C, the inside wall of the tubular element 30 acts on the arms 42 so as to bring them into a retracted position in which they extend along the bottom end of the shaft 20. In this position, the entire length of each arm 42 runs along the shaft 20. In this way, the boring tool 24 that projects at least in part beyond the bottom end of the tubular element 30 can pierce the soil freely.

(24) As can be seen in FIG. 9D, the two arms 42 are pivotally mounted of the bottom end 28 of the shaft 20 about axes that are orthogonal to the longitudinal direction X of the shaft 20. In this way, the arms 42 can extend laterally relative to the longitudinal direction X of the shaft 20.

(25) Spring means 44 (see FIG. 1) are arranged between the rotary shaft 20 and each of the two arms 42 so that whenever the arms 42 are outside the tubular element 30 they have a natural tendency to deploy relative to the axis X of the shaft 20 because of the action of the springs 44.

(26) In their deployed position, the arms 42 preferably form an angle that is open towards the bottom end of the shaft, as shown in FIG. 9D.

(27) It can be understood that, in the deployed position, the arms 42 serve to destructure the soil when the shaft 20 is rotated.

(28) As can be seen more clearly in FIG. 8, the rotary shaft 20 presents a section that is generally circular and of constant diameter. In the same manner, the tubular element 30 presents a section that is generally annular, with inside and outside diameters that are constant.

(29) The outside diameter of the rotary shaft 20 is smaller than the inside diameter of the tubular element 30. As can be seen in FIG. 1, an annular passage 60 is thus conserved between the two elements 20 and 30. As described in greater detail below, this passage 60 enables boring waste to be raised, i.e. a mixture of loosened soil and boring fluid from the boring operation.

(30) As can be seen in FIG. 1, the device 10 of the invention has a releasable coupling system 50 between the rotary shaft 20 and the tubular element 30.

(31) When the rotary shaft 20 is housed inside the tubular element 20, in other words when the mixer tool 40 is in the retracted position, the coupling system 50 is situated upstream from the mixer tool 40.

(32) In general, the coupling system 50 has first elements fastened to or forming integral portions of the tubular element 30, and second elements fastened to or forming integral portions of the rotary shaft 20. By co-operating, these first and second elements block certain degrees of freedom in relative movement between the tubular element 30 and the rotary shaft 20.

(33) In the example, the coupling system 50 comprises a plurality of lugs 54 formed on the inside wall of the tubular element 30 and adapted to co-operate with a corresponding number of housings 52 formed on the outside wall of the rotary shaft.

(34) FIGS. 6 and 7 show a segment 31 of the tubular element 30 on which the lugs 54 are formed. This segment 31 is threaded at each end 31a, 31b in order to enable it to be fastened respectively to a head tube 32 and a foot tube 33 of the tubular element 30.

(35) In this example, each lug 54 is in the form of an angular sector of an inside collar formed on the inside wall of the tubular element 30.

(36) In this example the coupling system has three lugs 54 that are distributed on the inside wall of the tubular element so as to form angles of 120 relative to one another.

(37) As can be seen in FIGS. 4, 5, and 8, the housings 52 are formed in projecting portions 53 that are formed on the periphery of the rotary shaft 20.

(38) FIGS. 4 and 5 in particular show a segment 21 of the rotary shaft 20 having the projecting portions 53. This segment 21 is threaded at each end 21a, 21b for fastening to a complementary segment of the rotary shaft 20.

(39) The outer radial faces of the projecting portions 53 run along the inside face of the tubular element 30.

(40) Between the projecting portions 53, the rotary shaft 20 has grooves 51 extending longitudinally (i.e. in the main direction X). Each groove 51 co-operates with a respective one of the housings 52 and is of sufficient width to enable a lug 54 to be slide inside it in the axial direction.

(41) In FIGS. 2 and 3, it can be seen that the depth of the grooves 51 is selected so as to leave a flow section that is sufficient for the boring waste. The projecting portions 53 constitute flow restrictions for said waste, which restrictions can be compensated, at least in part, by said grooves.

(42) In order to receive a lug 54, each housing 52 is in the form of a notch, specifically of profile complementary to the profile of the lugs 54, and formed in the outside walls of the projecting portions 53 of the rotary shaft 20.

(43) The coupling system is said to be in its first configuration when each lug 54 is housed inside a housing 52.

(44) Let F1 be the clockwise direction as shown in the various figures. In this configuration, if the rotary shaft 20 is set into rotation about the axis X in the direction F1, then each of the lugs 54 comes into abutment against the vertical wall 52c of its housing 52 (defined in a plane that is substantially axial). When the rotary shaft 20 moves, it thus drives the tubular element 30.

(45) When the rotary shaft 20 is simultaneously moved downstream, i.e. downwards in the various figures (direction referenced X1), then the lugs 54 come into abutment against the upstream horizontal walls 52b of their housings 52 (defined in a radial plane). Consequently, the rotary shaft 20 drives the tubular element 30 in its movement in translation.

(46) When the coupling system 50 is in its first configuration, and when as shown in FIGS. 9A and 9B the rotary shaft 20 is set into rotation in the clockwise direction F1 and moves in translation downstream (X1), i.e. into the depth of the soil, it takes the tubular element 30 with it.

(47) The soil is loosened by the boring tool 24 in the center and by the boring teeth 39 at the periphery of the device 10. Simultaneously, the boring fluid, generally water, is delivered into the soil in the proximity of the boring tool 24, by the longitudinal pipe 22.

(48) The mixture of soil and boring fluid rises via the annular passage 60 formed between the tubular element 30 and the rotary shaft 20. At the level of the coupling system 50, the mixture passes along the grooves 51 formed at the periphery of the shaft 20 between the projecting portions 53.

(49) The movements in translation and in rotation are continued until the bottom end of the tubular element 30 reaches the portion of soil to be treated ST, in other words the depth P.

(50) In order to enable the mixer tool 40 to be introduced into the portion of soil for treatment ST, the coupling system 50 is taken into its second position, as shown in FIG. 9C.

(51) While the tubular element 30 is held in position, either by friction against the soil or by a clamping device provided for this purpose, the rotary shaft 20 is pivoted in the anticlockwise direction F2 through about 45 so that the lugs 54 are extracted from their respective housings 52 and put into the grooves 51.

(52) As shown in FIG. 9D, the rotary shaft 20 is then moved in translation in a downstream direction (X1) until the lugs 54 leave said grooves 51.

(53) The coupling system is then in its second configuration, in which the rotary shaft 20 and the tubular element 30 are no longer coupled together, whether in rotation or in translation.

(54) The rotary shaft 20 can then be moved downstream (X1) until its bottom end, and in particular the mixer tool 40, becomes extracted from the tubular element 30 and penetrates into the portion of soil for treatment ST.

(55) When the arms 42 are deployed, the shaft 20 is rotated while simultaneously injecting fluid into the portion of soil ST via the bottom end of the shaft 20, such that the treated zone is confined to said portion of soil.

(56) Once the portion of soil has been treated down to the desired depth, the rotary shaft 20 is raised (X2) until the mixer tool 40 in particular is housed once more inside the tubular element 30.

(57) The rotary shaft 20 is moved in translation upstream along the main axis X, and it is simultaneously caused to rotate.

(58) Inevitably, since the outer tubular element is stationary, the grooves 51 of the rotary shaft 20 come into register with the lugs 54, which become received therein automatically.

(59) In order to extract the tubular element together with the rotary shaft, it would be relatively complicated (although possible if using sufficient precision) to reinsert each lug 54 into one of the housings 52 for the purpose of coupling the rotary shaft 20 and the tubular element 30 in translation for upstream movement.

(60) Consequently, as can be seen more particularly in FIG. 8, an internal collar 56 is formed upstream from the lugs 54 on the inside wall of the tubular element 30. This inside collar 56 has an inside diameter that is less than the diameter of the rotary shaft 20 in its portion situated downstream, in particular the diameter of the circle in which the projecting portions 53 are inscribed.

(61) The collar 56 forms a continuous annular border that ensures that the rotary shaft 20 is blocked in translation relative to the tubular element 30 regardless of the angular position of the rotary shaft 20.

(62) The abutment formed by the collar 56 makes it easy to withdraw the tubular element 30 simultaneously with the rotary shaft 20.

(63) FIGS. 10A to 10F show the forward assembly of the device 10 of the invention in which the rotary shaft 20 and the tubular element 30 are respectively constituted by a string of rods and by a string of tubes.

(64) In FIG. 10A, a bottom rod 201 (or first rod) of the rotary shaft 20 is fastened to a mover device comprising a rotary head 70, and it is surrounded by a bottom tube 301 (or first tube) of the tubular element 30. It should be observed that for reasons explained below, a portion of the first rod 201 projects from the top end of the first tube 301.

(65) A coupling system 50 of the above-described type is formed between the first rod 201 and the first tube 301, and brought into its first configuration. In this configuration, the first rod 201 and the first tube 301 are coupled together in rotation in the direction for screwing the rods together, which also corresponds for obvious reasons to the direction of rotation of the device during boring operations.

(66) As in the above-described example, a boring tool 24 is provided at the bottom end of the first rod 201, and a mixer tool 40 is provided between the coupling system 50 and the boring tool 24.

(67) Two guillotines, respectively an upstream guillotine 81 and a downstream guillotine 82 are arranged in register with the location where boring is to be performed, and thus in register with the portion of soil to be treated.

(68) In a first step, shown in FIG. 10B, the assembly is set into rotation by the rotary head 70 and it is moved in translation downstream so as to penetrate into the soil, until the first tube 301 is in register with the downstream guillotine 82 and the portion of the first rod 201 that extends beyond the tube 301 is in register with the upstream guillotine 81.

(69) The downstream guillotine 82 is clamped around the first tube 301.

(70) The first tube 301 and the first rod 201 are coupled together in rotation by the coupling system 50, so the first rod 201 is prevented from moving in the usual direction of rotation of the device.

(71) In contrast, rotating the rod 201 in the opposite direction releases its coupling with the first tube 301.

(72) In order to unscrew the rotary head 70, as shown in FIG. 10B, the first rod 201 is thus likewise held vise-like in the upstream guillotine 81.

(73) Once unscrewed, the rotary head 70 is raised and the upstream guillotine 81 is loosened (see FIG. 10C), in order to enable a second rod 202 and a second tube 302 to be screwed respectively onto the first rod 201 and the first tube 301 (see FIG. 10D).

(74) The assembly is once more set into rotation and introduced into the soil, as shown in FIG. 10E. Once again, the two guillotines 81, 82 are tightened.

(75) The rotary head 70 is unscrewed.

(76) As shown in FIG. 10F, the upstream guillotine 81 is once more loosened, and the rotary head 70 is moved away to enable a third rod and a third tube (no references) to be screwed respectively onto the second rod 201 and the second tube 301.

(77) The above-described set of steps is repeated as often as necessary for the borehole to reach a sufficient depth.

(78) The treatment device 100 in a second embodiment of the present invention is shown in FIGS. 11A, 11B, and 12.

(79) The mixer tool and the boring tool remain positioned as in the embodiment described above, and their respective structures likewise remain identical. They are therefore not shown and described again.

(80) This embodiment differs from the preceding embodiment essentially in that the coupling system 150 is situated at the top end of the device 100.

(81) Nevertheless, as above, it still comprises a bayonet system.

(82) The coupling system 150 comprises a plurality of lugs 154 (three in this example), that are now formed on the outside wall of the rotary shaft 120, and a corresponding number of housings 152 formed in the wall of the tubular element 130.

(83) Since the coupling system 150 is situated at the top end of the device, it is necessary for it to be capable of being dismantled in the event of the rotary shaft 120 and the tubular element 130 being constituted respectively by a string of rods and by a string of tubes.

(84) In this example, the coupling system 150 thus has two parts 158 and 159 that are releasably fastened respectively to the top end of the tubular element 130 and to the top end of the rotary shaft 120.

(85) A first part 158, in the form of a bushing, is adapted to co-operate with the top end of a tube of the tubular element 130 via its threaded end 158a (see FIG. 11A).

(86) A second part 159, of substantially cylindrical shape, is adapted to co-operate with the top end of a rod of the rotary shaft 20 via its threaded end 159a (see FIG. 11B).

(87) It can be understood that the three lugs 154 are adapted to slide in corresponding slots 152 formed in the first part 158.

(88) In the example of FIG. 11A, each slot 152 presents a first segment 155a extending longitudinally in the direction of the axis X, a second segment 155b extending transversely to said first segment 155a, and a return segment 155c.

(89) On the same principle as that described above with reference to the first embodiment, the coupling system 150 is said to be in its first configuration when each lug 154 is positioned in a corresponding return segment 155c formed in the tubular element 130.

(90) In this first configuration, the rotary shaft 120 and the tubular element 130 are coupled together in translation in a downstream direction, and in rotation in the clockwise direction F1 (see FIG. 12).