Micro-tunnelling device comprising an annular joint for the separation of drilling and lubricating fluids

Abstract

The invention relates to a microtunneling machine (12) comprising: a cutting module (100), a fluid circulation device (110) for injecting a drilling fluid (F) and aspirating drilling cuttings (D) in the front part of the cutting module, a device for injecting a lubricating fluid (L) outside the jacking pipe; The invention is characterized in that the cutting module (100) has an annular seal (150) located on the outer face (102a) of the cylindrical body (102), the diameter (D3) of the annular seal (150) being at least equal to the diameter (D2) of the cutter head (108), so that the annular seal (150) comes into contact with the ground during drilling to achieve fluid separation between the drilling fluid (F) and the lubricating fluid (L).

Description

Technical Field

[0001] The present invention relates to the field of tunneling in the ground, and more specifically the construction of micro-tunnels. The invention relates in particular to a micro-tunneling machine and its use. Previous Technique

[0002] The technique of creating micro-tunnels in the ground, also called micro-tunneling, differs from the creation of conventional tunnels in particular by the fact that micro-tunneling uses a digging machine, called a micro-tunneler, which is driven into the ground using pipes that will constitute the final structure, whereas conventional tunneling uses a tunnel boring machine that advances while resting on the segments that have been previously laid.

[0003] The assembly consisting of the micro-tunnel boring machine and the jacking pipes is pushed from the starting shaft by a jacking station equipped with hydraulic jacks. Once a jacking pipe is completely sunk into the ground, an additional jacking pipe is brought to the bottom of the shaft in the jacking station, between the last jacking pipe and the hydraulic jacks. The actuation of the latter therefore has the effect of exerting a thrust on the additional jacking pipe which, in turn, pushes and advances the assembly of jacking pipes and the micro-tunnel boring machine already sunk into the ground.

[0004] It is therefore the entire micro-tunnel, made up of the succession of sinking pipes and the micro-tunnel boring machine, which advances into the ground as the digging progresses.

[0005] The cuttings are evacuated by a drilling fluid circulation device, this fluid being for example water or drilling mud.

[0006] Typically, the cutting face is pressurized so that the drilling fluid, also called the slurry fluid, also serves to maintain a confining pressure providing frontal support for the excavation.

[0007] Furthermore, as the micro-tunnel lengthens, friction forces between the extrados of the jacking pipes and the ground will appear and increase. In order to limit friction forces, a lubricating fluid is injected outside the jacking pipes, in the annular space between the extrados of the jacking pipes and the ground.

[0008] The invention thus relates to a micro-tunneling machine comprising: a cutting module comprising a cylindrical body extending axially between a rear portion and a front portion, and a cutting head located at the front of the cylindrical body opposite the rear portion, the cutting head being rotatable relative to the cylindrical body about the axis of the cylindrical body, a fluid circulation device for injecting a drilling fluid and sucking up the drilling cuttings in the front portion of the cylindrical body, at least one sinking pipe located at the rear of the cylindrical body; a device for injecting a lubricating fluid outside the sinking pipe.

[0009] In conventional micro-tunneling machines, the lubrication fluid, which is injected under pressure, sometimes flows longitudinally towards the cutting module and is then sucked in by the pumps designed to suck up the excavation spoil. This phenomenon is amplified on downward slopes.

[0010] This situation has several disadvantages.

[0011] First of all, the suction of lubricating fluid has the disadvantage of increasing the consumption of lubricating fluid.

[0012] Another disadvantage is that the presence of lubricating fluid at the front of the machine makes it more difficult to control the confining pressure in the drilling chamber. In addition, contamination of the drilling fluid by the lubricating fluid requires treatment of the drilling fluid.

[0013] Document CN216518002 U describes a micro-tunneler according to the preamble of claim 1, which is equipped with a double collar. Statement of the invention

[0014] An aim of the invention is to propose a micro-tunneler which makes it possible to reduce the consumption of lubricating fluid while facilitating the regulation of the confinement pressure in front of the cutting module.

[0015] The invention achieves its aim by a micro-tunneler according to claim 1 in which the cutting module further comprises an annular seal located on the outer face of the cylindrical body, the diameter of the annular seal being at least equal to the diameter of the cutting head, so that the annular seal comes into contact with the ground during drilling to achieve a fluidic separation between the drilling fluid and the lubricating fluid.

[0016] The annular seal therefore has the effect of physically separating the lubricating fluid from the drilling fluid (marbling).

[0017] The annular seal has the effect of delimiting two fluidic zones, namely a drilling fluid zone and a lubrication zone containing the lubrication fluid. The annular seal is sized so that, in use, it comes into contact with the ground wall surrounding the cutting module. Also, the annular seal prevents unwanted mixing of the drilling fluid and the lubrication fluid, which keeps the confining pressure stable at the cutting head and, consequently, makes it easier to control the micro-tunneling machine.

[0018] The lubrication operation is also improved since the lubricating fluid remains confined in the lubrication zone and is not sucked up by the sluicing pumps. In turn, the improved lubrication reduces the thrust forces required and advantageously increases digging efficiency.

[0019] Furthermore, compared with the prior art, the invention avoids the pollution of the drilling fluid by the lubricating fluid, thereby reducing the treatment process of the drilling fluid containing the cuttings.

[0020] The ring seal can be an insert that is mounted on the cylindrical body by the operator before digging. It can also be integrated into the cylindrical body at the time of manufacturing the micro-tunneling machine.

[0021] Advantageously, the annular seal is located in the front part of the cylindrical body. This has the effect of increasing the lubrication surface around the cylindrical body, which further reduces friction forces against the ground and improves digging efficiency.

[0022] Without departing from the scope of the invention, the annular seal may consist of a single or multiple parts. Preferably, the annular seal is a flexible and / or elastic part. It is understood that the annular seal has a diameter greater than that of the cylindrical body, and at least a diameter greater than the rear portion of the cylindrical body.

[0023] According to the invention, the annular seal comprises a collar formed from a plurality of fins. It is understood that the collar preferentially surrounds the front part of the cylindrical body.

[0024] The fins are shaped to bear against the ground wall. They have a certain elasticity in order to adapt to the roughness of the ground. The fins can therefore deform independently of the others during the advancement of the micro-tunnel in order to maintain contact of the annular seal against the ground over substantially its entire periphery and, consequently, ensure fluid separation between the drilling and lubrication fluids.

[0025] According to the invention, the fins are juxtaposed and overlap laterally at least partially two by two.

[0026] The lateral overlap between two adjacent fins prevents fluid from flowing between the two fins, which improves the seal between the two fluids.

[0027] According to the invention, the fins are elastically movable relative to the cylindrical body.

[0028] The fins are configured to be flexible enough not to disrupt the existing terrain, but rigid enough to withstand the pressure of the lubricating fluid.

[0029] According to the invention, at least one of the fins is inclined relative to the cylindrical body.

[0030] Preferably, at least one of the fins is formed from a folded sheet metal having a base fixed to the cylindrical body and a plate forming an angle with the base.

[0031] More preferably, the base has a hole for receiving a fixing element to the cylindrical body.

[0032] Preferably, the internal angle between the base and the plate is greater than 90° before its insertion into the ground.

[0033] It is understood that, at the moment of insertion of the body into the ground, the plate comes into contact with the ground and pivots relative to the base to a position where the internal angle between the base and the plate is less than 90°. The plate, which tends to return to its initial position, is blocked in rotation by the ground. This has the effect of forcing the plate against the wall of the ground, thus ensuring a sealed contact between the plate and the ground.

[0034] Preferably, the internal angle is of the order of 120° before its insertion into the ground.

[0035] Advantageously, the diameter of the cutting head is greater than the outside diameter of the cylindrical body.

[0036] Preferably, but not exclusively, the outer diameter of the cylindrical body is between 500 mm and 3000 mm.

[0037] It is therefore understood that the lubricating fluid flows into the annular space located on the outer face of the cylindrical body and the land surrounding the cylindrical body.

[0038] Preferably, the cutting head comprises a cutting wheel which is provided with cutting tools projecting radially beyond the diameter of the cylindrical body.

[0039] Advantageously, the outside diameter of the sinking pipe is less than or equal to the diameter of the cylindrical body.

[0040] It is also understood that the lubricating fluid flows in the annular space between the outer face or extrados of the sinking pipe and the ground surrounding the sinking pipe.

[0041] Preferably, the sinking pipe comprises at least one injection orifice opening onto its outer face and cooperating with the lubricating fluid injection device.

[0042] Preferably, but not exclusively, to further facilitate the advancement of the micro-tunneler in the ground, the latter also comprises a lubrication ring arranged axially between the cylindrical body and the sinking pipe.

[0043] The invention finally relates to the use of a micro-tunneling machine according to the invention for manufacturing a micro-tunnel in a ground, said micro-tunnel consisting of a plurality of sinking pipes arranged one after the other. Brief description of the drawings

[0044] The invention will be better understood on reading the following description of an embodiment of the invention given as a non-limiting example, with reference to the appended drawings, in which: [ Fig. 1 ] There Figure 1 is a perspective view of an example of a micro-tunneling installation, arranged in the ground (not shown here) and comprising a micro-tunneler according to the invention; [ Fig.2 ] There Figure 2is a detailed view of the cutting module of the micro-tunneling machine of the Figure 1 ; [ Fig. 3 ] There Figure 3 is a schematic view of the micro-tunneling machine of the Figure 1 and its constituent elements; [ Fig.4 ] There Figure 4 is a top view of a fin of the annular seal of the cutting module of the Figure 2 before insertion into the ground; [ Fig.5 ] There Figure 5 is a side view of the fin of the Figure 4 before inserting the cutting module into the ground; and [ Fig.6 ] There Figure 6 illustrates several adjacent fins of the annular seal of the cutting module of the Figure 2 , after inserting the micro-tunneler into the ground. Detailed description of the invention

[0045] On the Figure 1 , an example of the implementation of a micro-tunneling installation has been illustrated 10 comprising a starting well 14 for a micro-tunneler 12. In this example, the well 14consists of a circular wall 16 made in a soil S (not shown here for readability). At the bottom of the well 14 there is a sinking station 16 equipped with sinking jacks 18 which extend in a sinking direction A. In the extension of the sinking jacks 18, an opening 20 through is provided in the circular wall 16. We understand that the micro-tunneler 12 is engaged in the ground, in a direction slightly inclined to the horizontal, through this opening 20.

[0046] The micro-tunneling machine 12 includes a cutting module 100 comprising a cylindrical body 102 having a diameter D1 extending axially between a rear portion 104 and a front part 106. The cutting module 100 further includes a cutting head108 which is located at the front of the cylindrical body 102, opposite the rear part 104.

[0047] Thanks to motor means known elsewhere, the cutting head 108 is rotatable relative to the cylindrical body 102 around the axis B of the cylindrical body. The cutting head has a diameter D2 so that the diameter of the excavation made in the ground has a cylindrical shape of diameter D2.

[0048] The cutting head 108 has a cutting wheel 109 which is equipped with cutting tools 111 projecting radially beyond the diameter D1 of the cylindrical body.

[0049] In this non-limiting example, the micro-tunneler further comprises a lubrication ring 170 which is arranged between the cylindrical body and the first sinking pipe 120.

[0050] As is also known, the cutting head 108 forms a slaughter chamber.

[0051] As schematized in Figure 3 , the micro-tunneling machine 12 further comprises a fluid circulation device 110 comprising means for injecting a drilling fluid F in the blast chamber and suck up the drill cuttings D in the front part of the cylindrical body. In this example, the drilling fluid F is a drilling mud.

[0052] As is also known, the cutting module 100 first went down into the well 14, it is then driven into the ground using driving jacks 18.

[0053] As is well known, the micro-tunneling machine 12 further comprises at least one first sinking pipe 120 having an outside diameter D4. The sinking pipe is placed at the rear of the cylindrical body 102.In this example, the outer diameter D4 of the jacking pipe is slightly smaller than the diameter D1 of the cylindrical body.

[0054] In this example, a first sinking pipe is illustrated. 120 and a second sinking pipe 122 arranged behind the first sinking pipe.

[0055] Once the cutting module is introduced into the ground S through the opening 20, the sinking jacks 18 are retracted and the first sinking pipe is lowered 120 so as to arrange it between the rear part of the cylindrical body 102 and the sinking jacks 18. These are then put into action so as to push the first jacking pipe 120 according to management A, so that the first jacking pipe pushes the cutting module 100 into the ground. After introducing the first jacking pipe 120,the sinking jacks are retracted 18 and the second sinking pipe is introduced 122 into the well so as to position it between the first sinking pipe 120 and the sinking jacks 16. The driving operation is repeated, so that the second driving pipe pushes the assembly consisting of the cutting module 100 and the first jacking pipe into the ground. These operations are repeated until the desired length of the micro-tunnel is obtained. At the end of the operation, the cutting module is removed and the succession of jacking pipes forms the micro-tunnel in the ground.

[0056] To facilitate the insertion of the sinking pipes into the ground, a device for injecting a lubricating fluid is provided. L outside the sinking pipes 120, 122. The lubrication fluid is injected onto the extrados of the sinking pipes. The injection device 130 lubricating fluidL has a reservoir 138 lubricating fluid L and pipes 134 which connect the reservoir 138 to the various sinking pipes 120, 122, as well as to the cylindrical body. e. The pipes 134 are connected to orifices 136 located on the peripheral wall of the sinking pipes, and also on the peripheral surface of the cylindrical body 102. These orifices 136 are better visible on the figures 1 And 3 . On the diagram of the Figure 3 , only pipes supplying the first sinking pipe have been shown.

[0057] Using the Figure 3 , we understand that the lubricating fluid L is injected into the annular space between the extrados of the sinking pipes and the ground, and also between the cylindrical body 102 and the land.

[0058] We understand in particular that the diameter D2 of the cutting head 108 is greater than the outer diameter D1 of the cylindrical body, so as to provide an annular space between the cylindrical body and the wall of the excavation.

[0059] The drilling fluid is injected in the front part 106 of the cylindrical body 108, so that the drilling fluid flows between the cutting face 11 and the cutting head 108, and also in the annular space between the cutting head 108 and the land.

[0060] According to the invention, the cutting module 100 further includes an annular seal 150 which is located on the outer face 102a of the cylindrical body. The diameter D3 of the annular seal 150 is at least equal to the diameter D2 of the cutting head 108 so that the annular seal 150comes into contact with the wall P of the excavated ground during drilling so as to achieve fluid separation between the drilling fluid F and the lubricating fluid L.

[0061] Thanks to the invention, the drilling fluid F and drilling fluid L do not mix. Furthermore, the lubricating fluid L is not sucked into the circulation device and does not disturb the marinating pressure of the drilling fluid F. In addition, the lubricating fluid L is not polluted by drilling fluid F.

[0062] As can be seen on the figures 1 to 3 , the annular seal 150 is located in the front part of the cylindrical body 100. In this example, the annular seal 150 includes a collar 152 formed from a plurality of fins 154. On the figures 4 to 6 ,the fins were illustrated 154 according to the invention. In this example, each of the fins 154 consists of a folded sheet metal plate having a base 158 fixed to the cylindrical body 100 and a plate 156 forming an angle α with the base.

[0063] As illustrated in particular in the Figure 6 , the fins 154 are juxtaposed and partially overlap laterally two by two, thanks to a lateral extension 156 has platelets 156. This lateral overlap improves the sealing of the annular seal 150.

[0064] The collar 152 extends annularly around the cylindrical body 102 so as to achieve axial sealing between the space defined between the cutting head 108 and the ground on the one hand and the annular space between the cylindrical body 102 and the wall P from the ground on the other hand.

[0065] In this example, the fins are elastically movable relative to the cylindrical body, so as to adapt to the roughness of the ground while maintaining the seal as the micro-tunneling machine advances into the ground. It can also be seen that the fins 154 are inclined relative to the cylindrical body. More precisely, the fins are inclined relative to the axis B of the cylindrical body 100.

[0066] Before the introduction of the micro-tunneling machine into the ground, as illustrated in Figure 5 , the angle between the base 158 and the plate 156 is greater than 90°, of the order of 120°. When introducing the cutting module into the ground, we understand that the plate 158of each fin engages with the ground, which causes it to pivot relative to the base so that the angle between the base and the plate, after insertion of the cutting module into the ground, is less than 90°, as illustrated in particular in figures 3 And 6 . In operation, the angle between the pad and the base is in the order of 45°-60°.

[0067] The plates, which tend to return to their initial position, are pressed against the ground, which allows the seal between the collar and the ground to be maintained locally despite the roughness of the ground.

[0068] Without departing from the scope of the present invention, the initial angle between the plate could be equal to or less than 90° as long as the plate rests against the ground.

[0069] Alternatively, the annular seal could also be made of a single piece, or of two half collars.

Claims

1. A micro-tunneling machine (12) comprising: a cutting module (100) comprising a cylindrical body (102) extending axially between a rear portion (104) and a front portion (106), and a cutting head (108) located at the front of the cylindrical body opposite the rear portion, the cutting head (108) being rotatable with respect to the cylindrical body (102) about the axis (B) of the cylindrical body, a fluid circulation device (110) for injecting a drilling fluid (F) and sucking up the drilling cuttings (D) in the front portion of the cylindrical body, at least one sinking pipe (120) located at the rear of the cylindrical body; an injection device (130) for injecting a lubricating fluid (L) outside the sinking pipe; wherein the cutting module (100) further comprises an annular seal (150) located on the outer face (102a) of the cylindrical body (102), the diameter (D3) of the annular seal (150) being at least equal to the diameter (D2) of the cutting head (108), such that the annular seal (150) comes into contact with the ground (P) during drilling to achieve a fluidic separation between the drilling fluid (F) and the lubricating fluid (L), wherein the annular seal (150) comprises a collar (152) formed of a plurality of fins (154) juxtaposed and elastically movable with respect to the cylindrical body, at least one of the fins (154) being inclined with respect to the cylindrical body, characterized in that the fins (150) overlap laterally at least partially in pairs.

2. The micro-tunneling machine according to claim 1, wherein the annular seal (150) is located in the front portion of the cylindrical body (100).

3. The micro-tunneling machine according to any one of the preceding claims, wherein at least one of the fins is made from a folded metal sheet having a base (156) attached to the cylindrical body (100) and a plate (158) forming an angle (α) with the base.

4. The micro-tunneling machine according to claim 3, wherein the angle (α) between the base (156) and the plate (158) is greater than 90° before its insertion into the ground.

5. The micro-tunneling machine according to any one of the preceding claims, wherein the diameter (D2) of the cutting head (108) is greater than the outer diameter (D1) of the cylindrical body.

6. The micro-tunneling machine according to claim 5, wherein the cutting head (108) comprises a cutting wheel (109) which is provided with cutting tools (111) projecting radially beyond the diameter (D1) of the cylindrical body.

7. The micro-tunneling machine according to any one of the preceding claims, wherein the outer diameter (D4) of the sinking pipe is less than or equal to the diameter (D1) of the cylindrical body.

8. The micro-tunneling machine according to any one of the preceding claims, wherein the sinking pipe comprises at least one injection orifice (136) opening onto its outer face and cooperating with the lubricating fluid injection device.

9. The micro-tunneling machine according to any one of the preceding claims, further comprising a lubricating ring (170) disposed axially between the cylindrical body (100) and the sinking pipe (120).

10. A use of a micro-tunneling machine (12) according to any one of the preceding claims for manufacturing a micro-tunnel in a ground (S), said micro-tunnel consisting of a plurality of sinking pipes (120, 122) arranged one after the other.

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