Machine for creating a double-diameter pile in the ground

Abstract

The invention relates to a machine (10) for making a two-diameter pile in the ground comprising: a casing (12) having a first diameter, the casing having a casing axis and a lower part comprising a first cutting element, the casing being mobile in rotation around the casing axis and mobile in translation along the casing axis; an auger (20) having a second diameter, smaller than the first diameter, and being coaxial with the casing, the auger having an auger axis and being mobile in rotation around the auger axis and mobile in translation along the auger axis, the auger having a lower part provided with an injection orifice (30);a coupling device (40), located in the lower part of the machine, comprising a free position in which the auger can rotate and translate relative to the casing and a coupled position in which the auger is fixed to the casing such that the rotation of the auger causes the concomitant rotation of the casing around the casing axis and the translation of the auger causes the concomitant translation of the casing along the casing axis; and an injection device (32) for injecting a binder into the soil via the injection orifice. Figure for the abstract: Figure 3;

Description

Title of the invention: Machine for driving a two-diameter pile in the ground technical field

[0001] The present invention relates to the field of the construction of bi-diameter piles in the ground in the context of geotechnical works such as foundations. Previous technique

[0002] In a known manner, a two-diameter pile comprises an upper portion and a lower portion arranged in continuity with each other, the diameter of the upper portion being greater than the diameter of the lower portion.

[0003] The first section is constructed to a depth of approximately 5 meters, allowing it to withstand horizontal forces. The length of the lower section is dimensioned to obtain the required vertical load-bearing capacity.

[0004] The advantage of a double-diameter pile, compared to a single-diameter pile whose diameter corresponds to the diameter of the upper portion, lies in the savings in concrete that are achieved.

[0005] The construction of a two-diameter pile makes it possible to reduce by approximately 20 to 40% the quantity of concrete to be used to obtain the desired mechanical properties.

[0006] The use of bi-diameter piles therefore has the effect of reducing the environmental impact of the foundation. Description of the invention

[0007] One object of the invention is to provide a machine for making a bi-diameter pile.

[0008] The invention achieves its goal by means of a machine for the construction of a two-diameter pile in the ground comprising:

[0009] a casing having a first diameter, the casing having a casing axis and a lower part comprising a first cutting element, the casing being mobile in rotation around the casing axis and mobile in translation along the casing axis;

[0010] an auger having a second diameter, smaller than the first diameter, and being coaxial with the casing, the auger having an auger axis and being movable in rotation around the auger axis and movable in translation along the auger axis, the auger having a lower part provided with an injection orifice;

[0011] a coupling device, disposed in the lower part of the machine, comprising a free position in which the auger can rotate and translate relative to the casing and a coupled position in which the auger is fixed to the casing so that the rotation of the auger causes the concomitant rotation of the casing around the axis of The casing and the translation of the auger result in the concomitant translation of the casing along the casing axis; and

[0012] an injection device for injecting a binder into the soil via the injection orifice.

[0013] It is understood that when the auger is coupled to the casing, the latter is mechanically linked to the auger. Since the casing is fixed to the auger, when the coupling device is in the coupled position, the movement of the auger causes the same movement of the casing in rotation and / or translation along the casing axis.

[0014] Preferably, the tubing axis is vertical.

[0015] The vertical movement of the auger in the ground, in the coupled position, causes the entire assembly consisting of the casing and the auger to be driven into the ground. This movement therefore results in drilling a first hole in the ground with a diameter equal to the first diameter of the casing.

[0016] It is also understood that, in free position, the auger is mobile in rotation and translation relative to the casing.

[0017] The auger has, in particular, a retracted position in which the casing is located axially in the lower part of the auger. Preferably, the machine is arranged so that the transition between the coupled position and the free position occurs when the auger is in the retracted position.

[0018] In the retracted position, the auger can be completely retracted into the casing or extend slightly beyond the lower end of the casing along the casing axis, particularly when the lower end of the auger is equipped with a cutting element.

[0019] In the free position of the coupling device, the auger can be extended axially beyond the lower end of the casing. This allows the auger to be driven into the ground without the casing, which remains at the same depth.

[0020] The binder, for example concrete, can be injected through the injection port as the auger is raised, initially filling the second hole to form the lower portion of the two-diameter pile. Then the auger is reattached to the casing, and the auger and casing are raised together while injecting the binder into the first hole to form the upper portion of the two-diameter pile, thus creating the two-diameter pile.

[0021] It is understood that the coupling device has the function of coupling the auger and the casing in rotation so that the rotation of the auger causes the rotation of the casing in the same direction and at the same speed of rotation.

[0022] The auger comprises a tubular auger body and at least one helical blade extending along the auger body. The lower end of the auger preferably comprises a second cutting element.

[0023] The casing is preferably devoid of helical blades.

[0024] The injection device preferably includes a binder supply line which is connected to an upper end portion of the auger.

[0025] Preferably, but not exclusively, the auger comprises a dip tube housed within the auger body. The dip tube is free to move relative to the auger body and has the injection port at its lower end. Such a dip tube is known elsewhere. To perform the injection, the dip tube is extended relative to the auger body to expose the injection port. During drilling, the dip tube is retracted to cover the injection port.

[0026] Advantageously, the machine according to the invention further comprises a lining tube having a third diameter which is greater than the second diameter and less than the first diameter, the lining tube being arranged in the casing being coaxial with said casing, while the auger is mobile in rotation and translation in the lining tube.

[0027] The third diameter of the casing tube is slightly larger than the second diameter of the auger. Preferably, the third diameter is less than 105% of the second diameter.

[0028] During the drilling stage, the cuttings are brought to the surface by circulating vertically between the auger and the casing tube.

[0029] Advantageously, the casing tube is rotationally mobile relative to the casing around the casing axis.

[0030] According to a preferred embodiment, the lining tube is fixed relative to the ground. To achieve this, the machine further includes a locking device to prevent the rotation of the lining tube relative to the ground.

[0031] The locking device prevents the casing from rotating with the auger during the drilling stage, whether the auger is rotationally coupled to the casing or not. This facilitates the removal of cuttings.

[0032] In the absence of a locking device, the possible rotation of the casing tube with the rotating auger can result from friction induced by the cuttings inside the casing tube during the auger's rotation. The cuttings then couple the casing tube to the auger. The inventor has observed that rotating the casing tube in the same direction as the auger generally has the disadvantage of preventing the cuttings from being brought up, creating a blockage.

[0033] According to a preferred embodiment, the locking member comprises at least one wing disposed in the upper part of the liner tube, the wing cooperating with an object stationary relative to the ground.

[0034] The stationary object on the ground can be, for example, a part of a tracked carrier, for example the mast, which supports the machine according to the invention. The wing comes to rest against the mast, thereby preventing the casing tube from rotating during the rotation of the auger.

[0035] Preferably, the coupling member comprises two wings arranged on either side of the liner tube.

[0036] The casing remains free to rotate relative to the casing tube. It is understood that when the auger is coupled to the casing, the assembly consisting of the auger and the casing rotates relative to the casing tube.

[0037] Preferably, the casing tube moves in translation with the assembly consisting of the auger and the casing, when the coupling device is in the coupled position.

[0038] To achieve this, the lining tube is connected to the casing via a pivot joint. This pivot joint has the dual function of guiding the rotation of the casing relative to the lining tube and of coupling the lining tube to the casing in translation, whereby the lining tube is driven in translation during the translational movement of the casing.

[0039] Advantageously, the coupling device is located in the lower part of the tubing.

[0040] According to one embodiment, the coupling device includes a clamping element arranged to pinch the auger.

[0041] Advantageously, the machine further comprises a sealing device disposed between the casing tube and the clamping element to prevent the entry of debris between the casing and the casing tube.

[0042] The coupling device further includes an actuator for actuating the clamping element.

[0043] Advantageously, the auger comprises a main blade and a secondary blade, and the clamping element is arranged to press radially on diametrically opposed portions of the main and secondary blades.

[0044] Preferably, the clamping element comprises a chuck.

[0045] Preferably, the chuck comprises two jaws mounted to the casing pivotally around at least one axis of rotation parallel and distant from the axis of the casing, the jaws being arched and arranged on either side of the auger.

[0046] According to a preferred embodiment, each of the two jaws is mounted to pivot around an axis of rotation.

[0047] Preferably, but not exclusively, the internal surface of the jaws is corrugated or provided with protrusions in order to increase the coefficient of friction between the chuck and the auger.

[0048] According to one embodiment, the jaws are actuated by an actuator connecting two ends of the jaws opposite the axis of rotation. This actuator can be a hydraulic cylinder. The extension of the cylinder causes the chuck to open, while the retraction of the cylinder causes the chuck to close and the auger to lock against the casing.

[0049] Preferably, the first cutting element extends annularly at the lower end of the tubing.

[0050] Preferably, the lower end of the casing has an opening whose diameter is slightly larger than the diameter of the auger. The first cutting element extends annularly around said opening. The first cutting element preferably comprises several cutting tools.

[0051] The invention further relates to an installation for the construction of a two-diameter pile in soil, comprising a machine according to the invention and a carrier equipped with a mast from which the machine is suspended, the carrier comprising a drive device to drive the auger in rotation around the auger axis and in translation along the auger axis.

[0052] The drive device includes a rotational drive device and a translational drive device along the auger axis, which is substantially vertical.

[0053] In the embodiment where the machine includes a lining tube, the wing of the locking member, when present, comes to rest against the mast of the carrier, which constitutes a stop preventing the rotation of the lining tube relative to the ground.

[0054] The invention also relates to a method for constructing a two-diameter pile in soil, in which:

[0055] A machine according to the invention is provided,

[0056] the coupling device is brought into the coupled position so as to secure the casing to the auger;

[0057] The auger is rotated using the drive device so as to drive the assembly consisting of the auger and the casing into the ground to a first depth, thereby drilling a first hole in the ground having a first diameter to a first depth; then

[0058] the coupling device is brought into a free position so as to detach the casing from the auger;

[0059] the auger is driven into the ground to a second depth, so as to drill a second hole in the ground in continuity with the first hole, the second hole having a second diameter smaller than the first diameter;

[0060] a binder is injected into the soil through the orifice of the auger while raising the auger to the first depth so as to fill the second hole;

[0061] the coupling device is brought into the coupled position so as to secure the casing to the auger;

[0062] The auger is raised again, together with the casing, while continuing the injection of binder into the soil so as to fill the first hole; then

[0063] the machine is removed from the ground.

[0064] The two-diameter pile is therefore made up of the first and second holes filled with binder. The first hole filled with binder constitutes the upper portion of the pile, while the second hole filled with binder constitutes the lower portion of the pile.

[0065] The two-diameter pile is made in a substantially vertical direction.

[0066] The upper portion of the two-diameter pile allows for the transfer of horizontal forces, which are greater in the upper part of the pile. The lower portion has a smaller diameter but is generally longer in order to ensure the load-bearing capacity of the pile.

[0067] Preferably, at least one reinforcement cage is inserted into at least one of the first and second holes filled with binder after the machine has been removed.

[0068] Advantageously, the machine further comprises a casing tube having a third diameter greater than the second diameter and less than the first diameter, the casing tube being coaxial with the casing and the auger being sliding in the casing tube, and in which the auger rotates relative to the casing tube during the drilling of the first and / or second holes.

[0069] Preferably, the casing tube is blocked from rotating relative to the ground during the drilling of the first and / or second holes.

[0070] Advantageously, the rotational coupling of the auger with the casing is achieved by tightening the auger blades. Description of the drawings

[0071] The invention will be better understood upon reading the following description of an embodiment of the invention given by way of non-limiting example, with reference to the accompanying drawings, in which:

[0072] [Fig-1] Fig. 1 illustrates, in a perspective view, an example of the realization of the machine according to the invention, and more particularly its lower part;

[0073] [Fig.2] The [Fig.2] is a front view of the machine of the [Fig.1];

[0074] [Fig.3] The [Fig.3] is a longitudinal sectional view of the machine of the [Fig.2];

[0075] [Fig.4] Fig.4 illustrates the machine of Fig.3 without the tubing casing, showing the mandrel;

[0076] [Fig.5] Fig.5 illustrates the installation according to the invention and a first step of the process according to the invention in which the casing and the auger are driven into the ground simultaneously so as to drill a first hole, the casing tube being blocked in rotation by the mast of a carrier and the auger being coupled with the casing;

[0077] [Fig.6] Fig.6 illustrates a second step of the process according to the invention in which the auger is decoupled from the casing and drills a second hole below the casing;

[0078] [Fig.7] Figure [Fig.7] illustrates the injection of binder into the second hole during the raising the auger;

[0079] [Fig.8] Figure 8 illustrates the injection of binder into the first hole during the ascent of the casing and auger, coupled to each other; and

[0080] [Fig.9] Fig.9 illustrates the two-diameter pile, equipped with a cage of reinforcement, produced by the process according to the invention. Detailed description

[0081] Figure 5 illustrates an example of an installation 100 according to the invention for driving a two-diameter pile P in soil S, comprising a machine 10 according to the invention, and a carrier 110 equipped with a mast from which the machine is suspended. In this example, the carrier 110 is a tracked carrier.

[0082] In this example, the mast is substantially vertical and the machine 10, which will be described in more detail below, is carried by a trolley 114 which is mobile in translation along the mast 112.

[0083] The actuation system of the carriage 114 is known from elsewhere and will not be described in more detail here.

[0084] Referring to figures 1 to 3, it can be seen that the machine 10 according to the invention comprises a casing 12 having a general cylindrical shape having a first diameter DI and a casing axis A. In this example, the casing axis is substantially vertical.

[0085] In figures 1 to 3, for the sake of readability, only the lower portion 14 of the casing 12 has been shown. The casing 12 also includes a cylindrical casing body 11, visible in figures 3 and 6, which connects to the lower portion 14.

[0086] The casing 12 has a lower portion 12a which is equipped with a first cutting element 18. In this example, the first cutting element 18 consists of a plurality of cutting tools 19 which extend annularly at the lower end 13 of the casing. The first cutting element is located at the lower end 13 of the casing, on a lower annular face 22 of a circular plate 15 of the casing.

[0087] In this example, the outer wall 12b of the casing is substantially flat and devoid of helical blades.

[0088] The diameter of the first cutting element 18 is substantially equal to or slightly greater than the first diameter Dl.

[0089] As will be explained in more detail below, the casing 12 is mobile in rotation around the casing axis A and mobile in translation along the axis of the casing A.

[0090] The machine 10 according to the invention further comprises an auger 20 having a second diameter D2, smaller than the first diameter D1. The auger 20 has an auger shaft B and comprises a tubular body 22, a main blade 24 which is helical and surrounds the tubular body 22, and a secondary blade 26 located in its lower part 20a of the auger. The secondary blade 26 is angularly offset by 180° relative to the main blade 24.

[0091] The second diameter D2 corresponds to the outside diameter of the main blade 24.

[0092] The auger 20 comprises a second cutting element 28 comprising a first part 28a disposed at the lower end of the main blade 24, a second part 28b disposed at the lower end of the secondary blade 26 and a third part 28c disposed at the lower end 22a of the tubular body 22.

[0093] As can be seen in [Fig.3], the auger 20 is coaxial with the casing 12.

[0094] The auger 20 is mobile in rotation around the auger axis B and mobile in translation along the auger axis B.

[0095] The auger 20 also includes an injection orifice 30 which is connected to an injection device 32 for injecting a binder into the soil S. This binder can be, for example, a concrete grout or mortar. The auger 20 is hollow so that the binder flows through the auger to the injection orifice 30. Without departing from the scope of the present invention, the auger may include several injection orifices. In this example, the auger 20 includes a dip tube 23, known elsewhere, which is free to move in translation relative to the tubular body 22, and the injection orifice is provided at a lower end portion of the dip tube. In a known manner, to perform the injection, the dip tube 23 is extended axially out of the tubular body to expose the injection orifice. During drilling, the dip tube 23 is retracted into the tubular body, as illustrated in [Fig.3], in order to mask the injection port.

[0096] The installation 100 further includes a drive device 130, arranged in the carriage 114, to drive the auger 20 in rotation around the auger axis B and in translation along the auger axis B.

[0097] Furthermore, the tubing 12 can also be guided in translation and rotation relative to the mast via a guiding element 132.

[0098] The machine 10 further comprises a coupling device 40, disposed in the lower part of the machine, comprising a free position in which the auger can rotate and translate relative to the casing 12, and a coupled position in which the auger is locked relative to the casing so that the rotation of the auger 20 causes the concomitant rotation of the casing around the casing axis, and the translation of the auger causes the concomitant translation of the casing along the casing axis A.

[0099] The coupling device 40 is controllable so that it can be placed in a free (or decoupled) position and in a coupled position.

[0100] In this example, when the coupling device is in the coupled position, the auger is fixed to the casing.

[0101] Still in this example, the coupling device 40 is located in the lower part of the casing. As can be seen in [Fig. 3], the coupling device 40 is arranged at the interior of the lower part 14 of the casing. The coupling device 40 is located above the circular plate 15. It includes a clamping element 42 arranged to grip the auger 20. The clamping of the auger by the clamping element 42 causes the casing to become fixed to the auger. Consequently, the movement of the auger, by translation and / or rotation, is accompanied by the concomitant movement of the casing. In other words, the movement of the casing is controlled by the auger when the coupling device is in the coupled position.

[0102] The clamping element 42 is arranged to press simultaneously, and radially on diametrically opposed portions of the main and secondary blades 24,26.

[0103] In this example, the clamping element 42 includes a chuck 44 which consists of two jaws 46 which are mounted to the plate 15 of the casing 12 in a pivotal manner around axes of rotation XI, X2 parallel and distant from the axis of casing A.

[0104] As can be seen in [Fig. 4], the jaws are arched and arranged on either side of the auger so as to be able to radially grip the main and secondary blades. To achieve this, the jaws 46 are actuated by an actuator 48, in this example a cylinder, which connects the two ends of the jaws that are opposite the axes of rotation XI, X2.

[0105] It is understood that the deployment of the cylinder has the effect of opening the jaws, that is to say, of moving them apart from each other, while the retraction of the cylinder has the opposite effect of closing the jaws.

[0106] When the auger is retracted into the casing 12, the pinching area of ​​the main and secondary blades is substantially at the same axial level as the clamping element 42. The coupling of the auger with the casing preferentially takes place when the auger is retracted.

[0107] Advantageously, the machine 10 further comprises a lining tube 60 having a tube axis C and having a cylindrical shape of diameter D3.

[0108] The lining tube is arranged inside the casing 12, coaxial with said casing. The lining tube is free to rotate relative to the casing around the casing axis A. In this example, the lining tube is connected to the casing body 11 by means of a pivot joint 17, which guides the rotation of the lining tube 60 relative to the casing 12, while preventing the translation of the lining tube 60 relative to the casing 12. The pivot joint 17 comprises an annular guide portion 17a fixed to the inner wall of the casing, and two annular portions 17b, 17c, fixed to the outer wall of the lining tube and enclosing the annular guide portion. Rollers 17d, mounted along the two annular portions, facilitate the rotation of the annular portion relative to the lining tube. The pivot joint thus achieves a translational coupling, along the casing axis A, of the casing tube 60 relative to the casing 12.Consequently, the displacement is in translation. The casing along the casing axis A causes the casing to move in translation.

[0109] The third diameter D3 of the casing tube 60 is greater than the second diameter D2 of the auger but less than the first diameter DI of the casing.

[0110] It is therefore understood that the lining tube is disposed inside the casing and that the auger is disposed inside the lining tube.

[0111] The machine further comprises a sealing device 57, visible in [Fig. 3], disposed between the casing tube 60 and the clamping element 42 to prevent the entry of excavation debris between the casing and the casing tube. In this example, the sealing device 57 is located at the lower end of the casing tube and includes an annular seal 59 which bears against the upper face of the jaws 46.

[0112] The third diameter D3 of the casing tube is slightly larger than the second diameter D2 of the auger.

[0113] The auger 20 is free to rotate and translate relative to the casing tube 60. When the coupling device is in the free position, the auger can translate and rotate relative to the casing tube. The auger can also rotate within the casing tube when the coupling device is in the coupled position.

[0114] The machine 10 also includes a locking device 62 to prevent the rotation of the casing tube relative to the ground S, particularly during the drilling operation. In this example, the locking device has two wings 62 arranged on the upper part of the casing tube 60. The wings project radially from the casing tube.

[0115] It can be seen in [Fig. 5] that one of the wings 62 cooperates with the mast 112 of the carrier. The mast is stationary relative to the ground so that the latter acts as a stop for the wing, which has the effect of blocking the rotation of the casing tube around the casing axis.

[0116] The locking device ensures that the casing tube does not rotate with the auger. Consequently, during drilling, the auger rotates relative to the casing tube around the auger axis, which facilitates the removal of cuttings by the rotation of the auger.

[0117] Using figures 5 to 9, we will now describe a method of implementing the process of constructing a two-diameter pile P in the soil S.

[0118] According to this method, a machine according to the invention is provided, such as that described above.

[0119] First, the installation 100 is positioned at the location where the pile P is to be made.

[0120] The coupling device 40 is brought into the coupled position so as to secure the casing 12 to the auger 20. The auger 20 is rotated around the auger axis by means of the drive device 130. As the auger 20 is secured to the casing 12, it is understood that rotating the auger causes the casing to rotate. The assembly consisting of the auger and the casing rotates as a single unit around the casing axis. This rotating assembly is then driven into the ground S to a first depth PI, so as to drill a first hole of length L1 in the ground S, the diameter of which is the first diameter DI of the casing 12.

[0121] In this example, the machine 10 further comprises a casing tube 16 having a third diameter larger than the second diameter and smaller than the first diameter. The casing tube 16 is coaxial with the casing and the auger is mounted to slide within the casing tube.

[0122] The casing tube 16 is prevented from rotating relative to the ground during the drilling of the first and second holes. In this example, the auger 20 is prevented from rotating relative to the ground during its rotation by means of the wing 62, which bears against the mast 112. Preventing the casing tube from rotating facilitates the removal of the excavated material to the surface by the auger 20.

[0123] After reaching the first depth PI, the coupling device 40 is brought into a free position so as to decouple the casing 12 from the auger 20, as a result of which the auger 20 can move, in translation and in rotation, relative to the casing 12.

[0124] As illustrated in [Fig.6], the auger 20 is driven into the ground to a second depth P2, so as to drill a second hole in the ground in continuity with the first hole.

[0125] The second hole has a generally cylindrical shape extending over a length L2 and whose diameter is the second diameter D2. In the figures of the example, the second hole has at its lower end a small third hole whose diameter is smaller than the diameter of the auger. This third hole has a small vertical height relative to the length L2 of the second hole.

[0126] As illustrated in [Fig. 7], a binder, for example concrete, is then injected into the soil S through the orifice 30 of the auger 20 while raising the auger to the first depth PI so as to fill the second hole with binder. The third hole, if present, is also filled with binder.

[0127] In this example, the plunger tube 23 is axially deployed out of the auger body 22 so as to expose the injection orifice 30.

[0128] Once the auger has risen substantially to the first depth PI, the coupling device is brought into the coupled position so as to secure the casing 12 to the auger 20.

[0129] The auger 20 is then raised, carrying the casing 12 along in its vertical movement, while the injection of binder into the soil continues in order to fill the first hole. This is illustrated in [Fig.8].

[0130] Finally, the machine is removed from the ground.

[0131] Before the binder solidifies, a reinforcement cage 70 is inserted into the first and second holes so as to obtain the reinforced pile P illustrated in [Fig.9].

Claims

Demands

1. Machine (10) for the construction of a two-diameter pile (P) in a soil (5) comprising: a casing (12) having a first diameter (Dl), the casing having a casing axis (A) and a lower part (12a) comprising a first cutting element (18), the casing being mobile in rotation around the casing axis (A) and mobile in translation along the casing axis; an auger (20) having a second diameter (D2), smaller than the first diameter (Dl), and being coaxial with the casing (12), the auger having an auger axis (B) and being mobile in rotation around the auger axis and mobile in translation along the auger axis, the auger having a lower part (20a) provided with an injection orifice (30);a coupling device (40), disposed in the lower part of the machine, comprising a free position in which the auger can rotate and translate relative to the casing and a coupled position in which the auger is fixed to the casing such that the rotation of the auger causes the concomitant rotation of the casing around the casing axis and the translation of the auger causes the concomitant translation of the casing along the casing axis; and an injection device (32) for injecting a binder into the soil via the injection orifice.

2. Machine according to claim 1, further comprising a lining tube (60) having a third diameter (D3) which is greater than the second diameter (D2) and less than the first diameter (D1), the lining tube being disposed in the casing being coaxial with said casing, while the auger is mobile in rotation and translation in the lining tube.

3. Machine according to claim 2, wherein the lining tube is rotationally movable relative to the casing around the casing axis.

4. Machine according to claims 2 or 3, further comprising a locking member (62) for blocking the rotation of the lining tube relative to the ground.

5. Machine according to claim 4, wherein the locking member (62) comprises at least one wing disposed in the upper part of the liner tube (60), the wing cooperating with an object stationary relative to the ground.

6. Machine according to any one of claims 1 to 5, in which the coupling device (40) is located in the lower part of the casing.

7. Machine according to claim 6, wherein the coupling device (40) comprises a clamping element (42) arranged to pinch the auger.

8. Machine according to claim 7, wherein the auger comprises a main blade (24) and a secondary blade (26), and the clamping element is arranged to press simultaneously on diametrically opposed portions of the main (24) and secondary (26) blades.

9. Machine according to claim 7 or 8, wherein the clamping element (42) comprises a chuck (44).

10. Machine according to claim 9, wherein the chuck (44) comprises two jaws (46) mounted to the casing pivotally about at least one axis of rotation parallel and distant from the axis of the casing, the jaws being arched and arranged on either side of the auger.

11. Machine according to claim 10, wherein the jaws are actuated by an actuator (48) connecting two ends of the jaws opposite to the axis of rotation.

12. Machine according to any one of the preceding claims, wherein the first cutting member extends annularily to the lower end (13) of the tubing.

13. Machine according to any one of the preceding claims, wherein the auger has a lower end provided with a second cutting member.

14. Installation (100) for making a two-diameter pile in soil, comprising a machine (10) according to any one of the preceding claims, a carrier (110) equipped with a mast (112) from which the machine is suspended, the carrier comprising a drive device for driving the auger in rotation around the auger axis and in translation along the auger axis.

15. A method for constructing a two-diameter pile in soil, wherein: a machine according to any one of claims 1 to 13 is provided; the coupling device is brought into the coupled position so as to secure the casing to the auger; the auger is rotated so as to drive the assembly consisting of the auger and the casing into the soil to a first depth, thereby drilling a first hole having a first diameter to a first depth; then the coupling device is brought into the free position so as to de- The auger casing is lidarized; the auger is driven into the ground to a second depth, so as to drill a second hole in the ground in continuity with the first hole, the second hole having a second diameter smaller than the first diameter; a binder is injected into the ground through the orifice of the auger while raising the auger to the first depth so as to fill the second hole; the coupling device is brought into the coupled position so as to secure the casing to the auger; the auger is continued to be raised, together with the casing, while continuing the injection of binder into the ground so as to fill the first hole; then the machine is removed from the ground.

16. Method according to claim 15 wherein at least one reinforcement cage (70) is inserted into at least one of the first and second holes filled with binder after removal from the machine.

17. A method according to claim 15 or 16, wherein the machine further comprises a casing tube (60) having a third diameter greater than the second diameter and less than the first diameter, the casing tube being coaxial with the casing and the auger being sliding in the casing tube, and wherein the auger rotates relative to the casing tube during the drilling of the first and / or second hole.

18. Method according to claim 17, wherein the casing tube is blocked from rotating relative to the ground during the drilling of the first and / or second hole.

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