Micro-tunneling machine with an annular seal for the separation of drilling and lubricating fluids

Abstract

The invention relates to a micro-tunneling machine (12) comprising: a cutting module (100), a fluid circulation device (110) for injecting a drilling fluid (F) and sucking up the drilling cuttings (D) in the front part of the cutting module, a device for injecting a lubricating fluid (L) outside the sinking pipe; The invention is characterized in that the cutting module (100) 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), so that the annular seal (150) comes into contact with the ground during drilling to achieve a fluidic separation between the drilling fluid (F) and the lubricating fluid (L). Figure for abstract: figure 3

Description

Title of the invention: Micro-cooper comprising an annular seal for the separation of drilling and lubricating fluids 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. Prior art

[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 by means of sinking pipes which will constitute the final structure, whereas conventional tunneling uses a tunnel boring machine which advances while resting on the segments which have been previously laid.

[0003] The assembly consisting of the micro-tunneling 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-tunneling machine already sunk into the ground.

[0004] It is therefore the entire micro-tunnel, consisting 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] Generally, the cutting face is pressurized so that the drilling fluid, also called sluicing fluid, also serves to maintain a confining pressure ensuring frontal support of the excavation.

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

[0008] The invention thus relates to a micro-tunneling machine comprising:

[0009] a cutting module comprising a cylindrical body extending axially between a rear part and a front part, and a cutting head located in front of the cylindrical body opposite the rear part, the cutting head being rotatable relative to the cylindrical body about the axis of the cylindrical body,

[0010] a fluid circulation device for injecting a drilling fluid and sucking the drilling cuttings in front of the cylindrical body,

[0011] at least one drilling pipe located behind the cylindrical body;

[0012] a device for injecting a lubricating fluid outside the drilling pipe.

[0013] In conventional micro-tunneling machines, it sometimes happens that the lubricating fluid, which is injected under pressure, flows longitudinally towards the cutting module and is then sucked by the pumps provided for sucking the excavation cuttings. This phenomenon is amplified on a downward slope.

[0014] This situation has several drawbacks.

[0015] First of all, the suction of the lubricating fluid has the disadvantage of increasing the consumption of lubricating fluid.

[0016] 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 blasting chamber. In addition, pollution of the drilling fluid by the lubricating fluid requires treatment of the drilling fluid. Statement of the invention

[0017] 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.

[0018] The invention achieves its aim by the fact that 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.

[0019] The annular seal therefore has the effect of physically separating the lubricating fluid from the drilling fluid (marining).

[0020] The annular seal has the effect of delimiting two fluidic zones, namely a drilling fluid zone and a lubrication zone containing the lubricating fluid. The annular seal is dimensioned so that, in use, it comes into contact with the ground wall surrounding the cutting module. Also, the annular seal makes it possible to avoid undesirable mixing of the drilling fluid and the lubricating fluid, which makes it possible to maintain stable the confining pressure at the cutting head and, consequently, to make it easier to control the micro-tunneling machine.

[0021] 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. As a result, the improvement in lubrication makes it possible to reduce the necessary thrust forces and advantageously increases the digging efficiency.

[0022] Furthermore, compared to the prior art, the invention avoids pollution of the drilling fluid by the lubricating fluid, which makes it possible to reduce the treatment process of the drilling fluid containing the cuttings.

[0023] The annular seal may be an added part that is mounted on the cylindrical body by the operator before digging. It may also be integrated into the cylindrical body at the time of manufacturing the micro-tunneling machine.

[0024] 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 the friction forces against the ground and improves the digging efficiency.

[0025] 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.

[0026] According to a preferred embodiment, the annular seal comprises a collar formed from a plurality of fins. It is understood that the collar preferably surrounds the front part of the cylindrical body.

[0027] The fins are shaped to bear against the wall of the ground. 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 microtunnel 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 lubricating fluids.

[0028] Advantageously, the fins are juxtaposed and overlap laterally at least partially two by two.

[0029] The lateral overlap between two adjacent fins prevents fluid from flowing between the two fins, which improves the seal between the two fluids.

[0030] Advantageously, the fins are elastically movable relative to the cylindrical body.

[0031] 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.

[0032] Advantageously, at least one of the fins is inclined relative to the cylindrical body- lindric.

[0033] Preferably, at least one of the fins is made from a folded sheet metal having a base fixed to the cylindrical body and a plate forming an angle with the base.

[0034] More preferably, the base comprises a hole for receiving an element for fixing to the cylindrical body.

[0035] Preferably, the internal angle between the base and the plate is greater than 90° before its insertion into the ground.

[0036] 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 sealed contact between the plate and the ground.

[0037] Preferably, the internal angle is of the order of 120° before its insertion into the ground.

[0038] Advantageously, the diameter of the cutting head is greater than the external diameter of the cylindrical body.

[0039] Preferably, but not exclusively, the outer diameter of the cylindrical body is between 500 mm and 3000 mm.

[0040] 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.

[0041] Preferably, the cutting head comprises a cutting wheel which is provided with cutting tools projecting radially beyond the diameter of the cylindrical body.

[0042] Advantageously, the outside diameter of the sinking pipe is less than or equal to the diameter of the cylindrical body.

[0043] 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.

[0044] Preferably, the sinking pipe comprises at least one injection orifice opening onto its outer face and cooperating with the lubricating fluid injection device.

[0045] Still preferably, but not exclusively, to further facilitate the advancement of the micro-tunneler in the ground, the latter further comprises a lubrication ring arranged axially between the cylindrical body and the sinking pipe.

[0046] The invention finally relates to the use of a micro-tunneler according to the invention for manufacturing a micro-tunnel in a ground, said micro-tunnel being made up of a plurality of sinking pipes arranged one after the other. Brief description of the drawings

[0047] The invention will be better understood on reading the following description of an embodiment of the invention given by way of non-limiting example, with reference to the appended drawings, in which:

[0048] [Fig-1] [Fig.l] is a perspective view of an example of a micro-installation tunneling, arranged in the ground (not shown here) and comprising a micro-tunneling machine according to the invention;

[0049] [Fig.2] [Fig.2] is a detail view of the cutting module of the micro-tunneling machine of [Fig.l];

[0050] [Fig.3] [Fig.3] is a schematic view of the micro-tunneling machine of [Fig.l] and its constituent elements;

[0051] [Fig.4] [Fig.4] is a top view of a fin of the annular seal of the cutting module of [Fig.2] before insertion into the ground;

[0052] [Fig.5] [Fig.5] is a side view of the fin of [Fig.4] before insertion of the cutting module into the ground; and

[0053] [Fig.6] [Fig.6] illustrates several adjacent fins of the annular seal of the cutting module of [Fig.2], after insertion of the micro-tunneling machine into the ground. Detailed description of the invention

[0054] In [Fig.l], an exemplary embodiment of a micro-tunneling installation 10 has been illustrated comprising a starting shaft 14 for a micro-tunneling machine 12. In this example, the shaft 14 consists of a circular wall 16 made in a soil S (not illustrated here for reasons of readability). At the bottom of the shaft 14 is a sinking station 16 provided with sinking jacks 18 which extend in a sinking direction A. In the extension of the sinking jacks 18, a through opening 20 is provided in the circular wall 16. It is understood that the micro-tunneling machine 12 is engaged in the ground, in a direction slightly inclined relative to the horizontal, through this opening 20.

[0055] The micro-tunneler 12 comprises a cutting module 100 comprising a cylindrical body 102 having a diameter DI extending axially between a rear portion 104 and a front portion 106. The cutting module 100 further comprises a cutting head 108 which is located at the front of the cylindrical body 102, opposite the rear portion 104.

[0056] By means of 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.

[0057] The cutting head 108 comprises a cutting wheel 109 which is provided with cutting tools 111 projecting radially beyond the diameter DI of the cylindrical body.

[0058] 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.

[0059] In a manner known elsewhere, the cutting head 108 forms a felling chamber.

[0060] As shown diagrammatically in [Fig.3], the micro-tunneler 12 further comprises a fluid circulation device 110 comprising means for injecting a drilling fluid F into the blasting chamber and sucking up the drilling cuttings D in the front part of the cylindrical body. In this example, the drilling fluid F is a drilling mud.

[0061] In a manner known elsewhere, the cutting module 100 is first lowered into the well 14, it is then driven into the ground using driving jacks 18.

[0062] In a known manner, 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 outside diameter D4 of the sinking pipe is slightly less than the diameter DI of the cylindrical body.

[0063] In this example, a first jacking pipe 120 and a second jacking pipe 122 arranged behind the first jacking pipe are illustrated.

[0064] Once the cutting module is introduced into the ground S through the opening 20, the driving cylinders 18 are retracted and the first driving pipe 120 is lowered so as to arrange it between the rear part of the cylindrical body 102 and the driving cylinders 18. The latter are then put into operation so as to push the first driving pipe 120 in the direction A, so that the first driving pipe pushes the cutting module 100 into the ground. After introduction of the first jacking pipe 120, the jacking cylinders 18 are retracted and the second jacking pipe 122 is introduced into the well so as to position it between the first jacking pipe 120 and the jacking cylinders 16. The jacking operation is repeated, so that the second jacking 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 microtunnel is obtained.At the end of the operation, the cutting module is removed and the succession of sinking pipes forms the micro-tunnel in the ground.

[0065] To facilitate the insertion of the sinking pipes into the ground, a device for injecting a lubricating fluid L is provided outside the sinking pipes 120, 122. The injection of the lubricating fluid is carried out on the extrados of the sinking pipes. The injection device 130 of the lubricating fluid L comprises a reservoir 138 of 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 in Figures 1 and 3. In the diagram of [Fig.3], there is shown only pipes supplying the first sinking pipe.

[0066] With the aid of [Fig. 3], it is understood 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 ground.

[0067] It is understood in particular that the diameter D2 of the cutting head 108 is greater than the external diameter DI of the cylindrical body, so as to provide an annular space between the cylindrical body and the wall of the excavation.

[0068] The drilling fluid is injected into the front part 106 of the cylindrical body 108, so that the drilling fluid flows between the cutting front 11 and the cutting head 108, and also in the annular space located between the cutting head 108 and the ground.

[0069] According to the invention, the cutting module 100 further comprises 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 150 comes into contact with the wall P of the excavated ground during drilling so as to achieve a fluidic separation between the drilling fluid F and the lubricating fluid L.

[0070] Thanks to the invention, the drilling fluid F and the drilling fluid L do not mix. Furthermore, the lubricating fluid L is not sucked in by 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 the drilling fluid F.

[0071] As can be seen in 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 comprises a collar 152 formed of a plurality of fins 154. In Figures 4 to 6, the fins 154 according to the invention have been illustrated. In this example, each of the fins 154 is made up 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.

[0072] As illustrated in particular in [Fig.6], the fins 154 are juxtaposed and partially overlap laterally two by two, thanks to a lateral extension 156a of the plates 156. This lateral overlap makes it possible to improve the sealing of the annular seal 150.

[0073] The collar 152 extends annularly around the cylindrical body 102 so as to provide 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 of the ground on the other hand.

[0074] 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-tunneler 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.

[0075] Before the introduction of the micro-tunneler into the ground, as illustrated in [Fig. 5], the angle between the base 158 and the plate 156 is greater than 90°, of the order of 120°. When the cutting module is introduced into the ground, it is understood that the plate 158 of 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 plate and the base is of the order of 45°-60°.

[0076] The plates, which tend to return to their initial position, are pressed against the ground, which makes it possible to locally maintain the seal between the collar and the ground despite the roughness of the ground.

[0077] 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 comes to bear against the ground.

[0078] Alternatively, the annular seal could also be made of a single piece, or of two half collars.

Claims

Claims

1. 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 relative 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), so 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 relative to the cylindrical body, at least one of the fins (154) being inclined relative to the cylindrical body, characterized in that the fins (150) overlap laterally at least partially two by two.;

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

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

4. Micro-tunneling machine according to claim 3, in which the angle (a) between the base (156) and the plate (158) is greater than 90° before its insertion into the ground.

5. 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 (Dl) of the cylindrical body.

6. A micro-tunneler 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 (Dl) of the cylindrical body.

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

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

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

10. Use of a micro-tunneler (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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