EP0580510B1 - Method, equipment and device for generating and injecting foam for digging of soil - Google Patents

Abstract

The partition (8) of the confinement chamber (9), the front and the rear of the excavator disc (7), the screw (10) for the removal of debris, as well as the peripheral skirt (6) of the boring tool (1), are provided with orifices (21) for injection of foam, in proximity to each of which at least one pressurised foam generator device (24) is situated, which device has its own operational control. <IMAGE>

Description

The subject of the present invention is a process of drilling holes, more particularly of digging galleries or tunnels, in an atmosphere contained, using a drilling tool, such as a tunnel boring machine, of the type into which foam is injected under pressure through a plurality of orifices, at front and rear of the excavator disc, in the cuttings reception room behind the disc excavator, through the tool skirt drilling and on the cuttings extraction screw. The invention also relates to digging equipment of soil and a device for generating and injecting pressure foam, for carrying out the process of the invention.

We know in the prior art drilling facilities for sandy clay soil, in confined atmosphere, which require balancing the ground pressure by means of a foam sent under pressure in the containment chamber; usually, the foam is sent simultaneously towards the front and towards the back of the excavator disc, through the skirt or peripheral shield of the drilling tool, and in the cuttings removal screw. The foam used must be sufficiently strong, under pressure from containment chosen, so that it is a suspension of cuttings in the foam which is transported by the screw evacuation.

In the known technique, a generator single foam, located at a certain distance back of the drilling tool, generates foam necessary, and this is conveyed by a pipe to the level of the digging point, where it is distributed by a series of branches up to each injection points.

In practice, we find that we cannot not get it that way, at the injection points, homogeneous quality foam with pressure defined and controllable. In addition, foam injection cannot be adapted to actual conditions encountered at every moment of the advancement of the construction site.

The object of the invention is precisely to overcome this major drawback, by providing a process and equipment for digging all types of soil furniture or massive rock requiring lubricant unclogging, and ensuring performance and safety improved compared to techniques and installations earlier.

To this end, the subject of the invention is a process and equipment for direct injection of a expansive lubricant in the immediate vicinity of the job. The action of the expanded lubricant in the work results on very cohesive soils by a momentary absence of adhesion phenomena developed by this type of material and avoids swelling.

In what follows we mean by foam under pressure, foaming solution and foaming product, all expanded lubricant, solution of this agent lubricant and lubricating agent, capable of filling the unclogging function of the excavated ground.

• au moins un dispositifs, situé dans le voisinage immédiat de la cloison arrière de la chambre de réception des déblais, et l'on injecte la mousse sous pression dans ladite chambre; et/ou,
• au moins un dispositif situé dans le voisinage immédiat de l'arbre creux relié aux orifices placées sur le disque excavateur, et l'on injecte la mousse sous pression dans ledit arbre creux; et/ou,
• au moins un dispositif, situé dans le voisinage immédiat de la vis d'évacuation des déblais, et l'on injecte la mousse sous pression dans ladite vis; et/ou,
• au moins un dispositif situé dans le voisinage immédiat de la jupe périphérique de l'outil de forage, et l'on injecte la mousse sous pression vers l'extérieure à travers ladite jupe.

The methods according to the invention are characterized in that foaming solution and air are transported into the drilling tool where said foam is generated under pressure by:

• at least one device, located in the immediate vicinity of the rear wall of the cuttings receiving chamber, and the foam is injected under pressure into said chamber; and or,
• at least one device located in the immediate vicinity of the hollow shaft connected to the orifices placed on the excavator disc, and the foam is injected under pressure into said hollow shaft; and or,
• at least one device, located in the immediate vicinity of the cuttings discharge screw, and the foam is injected under pressure into said screw; and or,
• at least one device located in the immediate vicinity of the peripheral skirt of the drilling tool, and the foam is injected under pressure towards the outside through said skirt.

By drilling tool is meant any means of digging of the type comprising a drilling cutter, such that for example a tunnel boring machine using a disc excavator.

According to other characteristics advantageous of the process of the invention, the generation of pressure foam, either independently at the level of each of the generation devices and pressure foam injection, i.e. at the level of a plurality of groups of these devices.

• pression de confinement,
• couple du disque excavateur,
• couple de la vis d'évacuation des déblais,
• vitesse d'avancement de l'outil de forage.

The control of the generation of foam under pressure is carried out as a function of at least one of the following parameters:

• confinement pressure,
• torque of the excavator disc,
• torque of the cuttings discharge screw,
• advancement speed of the drilling tool.

According to a preferred embodiment of the process of the invention, each level is ensured pressure generating device, flow constant foaming solution, and air pressure determined.

• la cloison arrière de la chambre de réception des déblais,
• l'avant et l'arrière du disque excavateur,
• la vis d'évacuation des déblais,
• la jupe périphérique de l'outil de forage,

sont pourvus d'orifices d'injection de mousse sous pression, et des moyens de génération de mousse sous pression reliés à ces orifices, et est caractérisé en ce que les moyens de génération de mousse sont constitués d'une pluralité de dispositifs alimentés chacun, en solution moussante par une conduite, et en air comprimé par une autre conduite, chaque dispositif générateur de mousse sous pression étant situé à proximité immédiate d'un orifice d'injection, ou d'un groupe d'orifices d'injection, qui lui est associé.The invention also relates to equipment for digging soils in a confined atmosphere, intended for the implementation of the above method. This equipment is of the type comprising, a drilling tool of which:

• the rear wall of the cuttings receiving room,
• the front and rear of the excavator disc,
• the excavation screw,
• the peripheral skirt of the drilling tool,

are provided with pressure foam injection ports, and pressure foam generation means connected to these ports, and is characterized in that the foam generation means consist of a plurality of devices each supplied, in foaming solution via a line, and in compressed air through another line, each pressurized foam generating device being located in the immediate vicinity of an injection orifice, or a group of injection orifices, which is associated.

According to a first preferred form of embodiment, the equipment of the invention comprises for each pressure foam generating device a independent operation control.

According to a second preferred form of realization of the equipment of the invention, the pressurized foam generating devices are grouped into a plurality of sets of devices, each set being equipped with an independent control Operating.

According to a third preferred form of realization of the equipment of the invention, the pressurized foam generating devices are grouped into a plurality of sets of devices, each device within a set being equipped an independent operating control.

• une cuve d'équilibre partiellement remplie de solution moussante,
  • un collecteur d'alimentation des dispositifs générateurs de mousse sous pression, en solution moussante, partant du fond de cette cuve d'équilibre.
• un collecteur d'alimentation des dispositifs générateurs de mousse sous pression, en air comprimé, partant du sommet de cette cuve d'équilibre.

Advantageously, the equipment of the invention comprises a train following the drilling tool, carrying on a trailer:

• a balance tank partially filled with foaming solution,
  • a supply manifold for the foam generating devices under pressure, in foaming solution, starting from the bottom of this balancing tank.
• a manifold for supplying compressed foam generating devices with compressed air, starting from the top of this equilibrium tank.

• un ou plusieurs réservoirs de produit moussant,
• des pompes de transfert de produit moussant et d'eau vers la partie inférieure de la cuve d'équilibre,
• un compresseur d'air relié à la partie supérieure de cette cuve éventuellement par l'intermédiaire d'un réservoir tampon.

According to a particular embodiment of the equipment of the invention, the follower train carries, preferably on the same trailer as the balance tank:

• one or more foaming product tanks,
• foam and water transfer pumps to the lower part of the balancing tank,
• an air compressor connected to the upper part of this tank possibly via a buffer tank.

The invention also relates to a device for generating and injecting pressure foam for equipment according to the invention.

• un corps d'alimentation en solution moussante et en air comprimé;
• une chambre d'expansion emplie d'un garnissage, et,
• une buse de sortie de forme convergente.

This pressure foam generation and injection device includes:

• a foaming solution and compressed air supply body;
• an expansion chamber filled with a lining, and,
• an outlet nozzle of converging shape.

Advantageously, the body supply comprises two supply ducts, know a foaming solution supply pipe fitted a flow regulator and preferably a detector flow, and a compressed air supply duct fitted preferably a pressure sensor, these two conduits opening into a single conduit which opens itself in the expansion chamber.

According to a preferred embodiment of the device for generating and injecting foam under pressure, according to the invention, the single duct is provided a foaming solution expansion sensor in the room, connected to a synoptic control panel indicating the generation and injection devices pressure foam in service, and informing possible operating anomalies thereof.

According to a particular embodiment of the device of the invention, the expansion chamber has a grid at its entrance and at its exit calibrated.

According to another embodiment feature of the device of the invention, the lining of the expansion chamber is a loose packing, in particular made up of roughly shaped elements toric.

Other advantages and characteristics of the invention will appear on reading the example which follows, it being understood that this example cannot be interpreted as any limitation to claims.

• la figure 1 est une vue schématique partielle d'un équipement de creusement de tunnel conforme à l'invention ;
• la figure 2 illustre schématiquement l'alimentation des dispositifs de génération et d'injection de mousse ;
• la figure 3 est une vue en coupe longitudinale d'un dispositif de génération et d'injection de mousse ; et
• la figure 4 représente en coupe, à plus grande échelle, un élément du garnissage du dispositif de la figure 3.

This exemplary implementation of the invention relates to a tunnel boring machine and will be described with reference to the appended drawings, in which:

• Figure 1 is a partial schematic view of tunnel digging equipment according to the invention;
• Figure 2 schematically illustrates the supply of foam generation and injection devices;
• Figure 3 is a longitudinal sectional view of a device for generating and injecting foam; and
• FIG. 4 represents in section, on a larger scale, an element of the lining of the device of FIG. 3.

FIG. 1 shows the arrangement general of tunneling equipment of which the diameter can be of the order of 7 m, the pressure of confinement of about 1.5 bar, the torque of the disc 600 ton excavator. minute, and speed advancement of 5 mm / minute. This equipment includes essentially a tunnel boring machine (1) to which a follower train (2) consisting of a series of trailers (3), and an apparatus (4) for generation and injection foam in the forehead region (5).

The TBM includes a skirt or shield cylindrical (6), of substantially horizontal axis X-X, open green at the rear and fitted at its front end with a excavator disc (7). A short distance from this disc, a transverse watertight partition (8) is fixed in the skirt and delimits with the disc a chamber (9) of containment and reception of cuttings. A screw (10) for the removal of cuttings obliquely from the bottom of the chamber (9), and its casing passes through the partition (8) of waterproof way.

The trailers (3) of the following train are harnessed to each other and carry all of the devices necessary for the advancement of the site. For the needs of this description, no one will describe that one of these trailers, referenced (3A) and represented schematically in Figure 1, which shows part of the aforementioned apparatus (4).

More specifically, the trailer (3A) carries a foaming tank (11), a balancing tank (12) and a control cabinet (13). A pipe (14) of foaming product, equipped with a pump (15), opens in the discharge line (16) of a pump (17) supplied for example by a water pipe (18) of the network. The resulting foaming solution reaches the lower part of the tank (12). A compressor air (19) also fixed on the trailer (3A) sending compressed air in a buffer tank (20) connected to the upper part of the tank (12).

• dans le disque (7), une série d'orifices (21) d'injection de mousses disposées à différentes distances de l'axe X-X et orientées certaines vers l'avant, c'est-à-dire vers le front de taille, et l'autre vers l'arrière, c'est-à-dire débouchant dans la chambre (9). Chaque buse est reliée par un conduit (22) intérieur au disque à un arbre creux central (23) obturé à ses deux extrémités et traversant à joint étanche la cloison (8) ;
• derrière la cloison (8), une série de dispositifs (24) de génération et d'injection de mousse. L'un de ces dispositifs débouche dans l'arbre (23). Plusieurs autres débouchent directement dans la chambre (9) à travers des orifices de la cloison (8) ; d'autre débouchent dans le carter de la vis (10) ; et d'autres encore débouchent radialement à l'extérieur de la jupe (6).

The apparatus (4) comprises another part mounted in the tunnel boring machine (1), namely:

• in the disc (7), a series of orifices (21) for injecting foams arranged at different distances from the axis XX and oriented some towards the front, that is to say towards the cutting face, and the other towards the rear, that is to say opening into the chamber (9). Each nozzle is connected by a conduit (22) inside the disc to a central hollow shaft (23) closed at its two ends and passing through the partition (8);
• behind the partition (8), a series of devices (24) for generating and injecting foam. One of these devices opens into the tree (23). Several others open directly into the chamber (9) through orifices in the partition (8); others open into the housing of the screw (10); and still others open radially outside the skirt (6).

Each device (24) is powered independently by two supply lines, at know a line (25) of foaming solution and a compressed air line (26). All pipes (25) and (26) start from a distribution box (27) to which lead to a collector (28) for supplying foaming solution which leaves from the bottom of the tank (12), and a compressed air supply manifold (29) which from the top of this tank.

As seen in Figure 2, the cabinet (27) includes a solution distribution box (30) foaming and an air distribution box (31) compressed.

The box (30) includes an inlet pipe (33) connected to the manifold (28) and provided with a main solenoid valve (34) and a flow controller (35). Downstream of the latter leave as many branches (36) that there are devices (24), each bypass being fitted with a manual shut-off valve (37) and a solenoid valve (38) and being connected to the pipe (25) of the associated device (24).

The box (31) includes a pipe inlet (39) fitted with a main solenoid valve (40) and connected to the collector (29). Downstream of the solenoid valve (40) leave as many diversions (41) as there are device (24), each branch being equipped with a manual shut-off valve (42) and a solenoid valve (43) and being connected to the pipe (26) of the device (24) associated.

FIG. 3 shows the structure of a device (24) for generating and injecting foam. The device includes a supply body (44), an expansion chamber (45) and an outlet chamber (46). The device can have a length of the order of 0.6 m and a diameter of the order of 0.10 m for a foam production of the order of 200 l / min.

The body (44) comprises two conduits (47) of foaming solution and (48) compressed air connected respectively to lines (25) and (26) corresponding. The conduit (47) includes a detector flow (49) followed by a flow regulator (50) and a sprinkler (51). The conduit (48) includes a detector air pressure (52) followed by a nozzle (53). Downstream sprinklers, the two conduits (47) and (48) are join in a single outlet duct (54), provided a control sensor (61), and said single conduit (54) outlet opens into the chamber (45).

The chamber (45) is cylindrical, coaxial with conduit (54) and fixed at one end to the body (44). It has at each end "a calibrated grid (55) and is filled with loose packing (56). As shown in Figure 4, packing elements have been shown to consist of elements (57) of generally toric shape, of the type '"necklace pearls", glass or ceramic, which are inert materials vis-à-vis the foaming solution.

The outlet nozzle (46) forms a cap fitted on the downstream end of the expansion chamber. It has a convergent shape between an inlet diameter neighbor of diameter of the chamber (45) and a diameter of significantly smaller output. The nozzle can be directly connected to the foam injection port corresponding, in the partition (8), the housing of the screw (10), the skirt (6) or the hollow shaft (23). Alternatively, if the need for implantation requires it, a short stretch of tube can connect the outlet of the nozzle to the orifice injection (21). For example, the device (24) can be fixed by clamps along the partition (8) and the nozzle can be connected by an elbow to the orifice injection (21).

In operation, the site advances by successive steps corresponding to the length of a ring (58) of the tunnel lining (Figure 1). Each ring consists of several prefabricated segments in circle sector assembled to each other.

During each step in advance, the disc (7), driven in rotation, digs the waist while a ring of jacks (59) parallel to the axis X-X, one of which is shown schematically in Figure 1, taking support on the last ring (58) in place, cause the forward movement of the TBM and the train follower.

During this advance, foam generated under pressure by a device (24) is injected into the hollow shaft (23) and, from there, on the cutting face and in the chamber (9) through the injection orifices (21); foam, generated by the other devices (24), is injected directly into the chamber (9) by the nozzles (21); foam generated by others devices (24), is injected directly into the chamber (9) and in the housing of the screw (10), and also directly around the shield (6). Towards the back, the foam is retained by a filling cement base previously injected around the rings (58) of coating already in place;

The cuttings pass through the lights of the disc (7), remain more or less suspended in the foam, and the screw (10) discharges back a mixture cuttings and moss, which is not recycled.

The control cabinet 13 (Figure 1) controls on the one hand the dosage of the foaming solution and the filling of the tank (12), and on the other hand solenoid valves (38) and (43) (Figure 2). She can thus activate or deactivate each device (24).

The cabinet (13) can also be adjusted to will the foam outlet pressure, per action on the compressor (19). This pressure, of the order of some absolute bars, for example is greater than one predetermined value, which can be of the order of 1 bar, at the desired containment pressure. However, in this example the foaming solution flow rate of each device (24) is constant and regulated by the regulator (50) (Figure 3). Monitoring by detectors (49) and (52) trigger alarms in the event of incident, their exit signals being sent via a line (60) (Figure 3). The proper functioning of each injector is thus constantly checked.

In addition, the single duct (54) is equipped a control sensor (61) detecting the phenomenon expansion of the foaming solution in the room (45), so that in the event of a malfunction, a alert signal is transmitted by line (60) to a general control panel in the cab steering. This synoptic table makes it possible to monitor the foam generation and injection devices service and through the control sensor (61), visualize a possible anomaly of their operation.

The choice of injection pressure for the foam can for example be made according to the following parameters: Containment pressure, i.e. back pressure to be established in the chamber (9), torques exerted on the disc (7) and on the screw (10), and advancement speed of the TBM. This pressure can be actually obtained at each injection point since the foam is produced in its immediate vicinity and is not transported over long distances with the creation of random pressure drops. By elsewhere, the choice and number of injectors to be used service depends on the terrain encountered and the various site parameters and can be adjusted at will. The whole management of the switchgear (4) can be largely automated, in particular by a expert system.

Optionally, the same device (24) can be connected to a small number of injection ports immediately neighbors and, in some cases, several devices (24) can be controlled as a group.

Claims (18)

1. Equipment for excavating earth in a confined atmosphere, of the type that includes, a drilling tool (1) for which, the rear bulkhead (8) of the chamber (9) for receiving excavated material, the front and the rear of the excavator disc (7), the screw (10) for clearing out the spoil, and the peripheral skirt (6) of the drilling tool, are provided with orifices (21) for the injection of foam under pressure, and means of generating foam under pressure connected to these orifices, characterised in that the means of generating foam is made up of a plurality of devices (24), each fed with a foam solution by a pipe (25), and with compressed air by another pipe (26), each device (24) for generating foam under pressure being situated in immediate proximity to an injection orifice (21), or a group of injection orifices (21) which is linked to it.
2. Equipment according to Claim 1 characterised in that it comprises :

   at least one device (24) situated in the immediate vicinity of the rear bulkhead (8) of the chamber (9) for receiving excavated material, in such a way as to inject the foam under pressure into said chamber (9); and/or

   at least one device (24) situated in the immediate vicinity of the hollow shaft (23) connected to the injection orifices (21) positioned on the excavator disc, in such a way as to inject the foam under pressure into said hollow shaft (23); and/or

   at least one device (24) situated in the immediate vicinity of the screw (10) for clearing out the spoil, in such a way as to inject the foam under pressure into said screw (10); and/or

   at least one device (24) situated in the immediate vicinity of the peripheral skirt (6) of the drilling tool (1) in such a way as to inject the foam under pressure into and towards the exterior through said skirt (6).
3. Equipment according to one of Claims 1 to 2, characterised in that it comprises, for each device (24) for generating foam under pressure, an independent operational control.
4. Equipment according to one of Claims 1 to 2, characterised in that the devices (24) for generating foam under pressure are grouped together into a plurality of groups of devices, each group being equipped with an independent operational control.
5. Equipment according to one of Claims 1 to 2, characterised in that the devices (24) for generating foam under pressure are grouped together into a plurality of groups of devices, each device within a group being equipped with an independent operational control.
6. Equipment according to any one of Claims 1 to 5, characterised in that it includes a following train (2) for the drilling tool (1), that carries on a trailer (3A) a balancing tank (12) partially filled with foam solution, a collector (28) for supplying the foam solution and a collector (29) for supplying compressed air, for said devices (24) for generating foam under pressure, the collector (28) and the collector (29) running from the bottom and the top of this tank respectively.
7. Equipment according to Claim 6, characterised in that the following train (2) carries, preferably on the same trailer (3A) as the balancing tank (12), one or more reservoirs (11) of foam product, pumps (15, 17) for the transfer of foam product and water towards the lower part of the balancing tank (12) and an air compressor (19) connected to the upper part of this tank, possibly with a buffering reservoir (20) in between.
8. Device (24) for generating and injecting foam under pressure for equipment according to any one of Claims 1 to 7, characterised in that it includes :

   a unit (44) supplying foam solution and compressed air

   an expansion chamber (45) filled with packing (56) ; and,

   an outlet nozzle (46) of the combining cone type.
9. Device according to Claim 8, characterised in that the supply unit (44) comprises two feed pipes, namely a pipe (47) for supplying foam solution fitted with a flow rate regulator (50) and preferably a flow rate detector (49), and a pipe (48) for supplying compressed air, preferably fitted with a pressure detector (52), these two pipes feeding into a single pipe (54) which itself feeds into the expansion chamber (45).
10. Device according to Claim 9, characterised in that the single pipe (54) is fitted with a sensor (61) for the control of the expansion of the foam solution in the chamber (45), connected to a control board by the line (60).
11. Device according to one of Claims 7 to 10, characterised in that the expansion chamber (45) includes a calibrated screen (55) at its inlet and at its outlet.
12. Device according to one of Claims 7 to 11, characterised in that the packing (56) is a bulk packing material, notably made up of roughly torus shaped elements (57).
13. Method of using equipment for excavating earth in a confined atmosphere, the equipment being of the type that includes a drilling tool (1) into which the foam is injected under pressure through a plurality of injection orifices (21) positioned, on the rear bulkhead (8) of the chamber (9) for receiving the spoil, at the front and at the rear of the excavator disc (7), on the screw (10) for clearing out the spoil and on the peripheral skirt (6), characterised in that the foam solution is conveyed through a pipe (25) and the air through another pipe (26) into the drilling tool (1) where said foam is generated under pressure by;

    at least one device (24), situated in the immediate vicinity of the rear bulkhead (8) of the chamber (9) for receiving the spoil, and the foam is injected under pressure into said chamber (9) ; and/or,

    at least one device (24), situated in the immediate vicinity of the hollow shaft (23) connected to the orifices (21) positioned on the excavator disc (7), and the foam is injected under pressure into said hollow shaft (23) ; and/or,

    at least one device (24), situated in the immediate vicinity of the screw (10) for clearing out the spoil, and the foam is injected under pressure into said screw (10) ; and/or,

    at least one device (24), situated in the immediate vicinity of the peripheral skirt (6) of the drilling tool (1), and the foam is injected under pressure towards the exterior through said skirt (6).
14. Method according to Claim 13, characterised in that the generation of the foam under pressure is independently controlled at each of the devices (24) or at a plurality of groups of these devices (24).
15. Method according to Claim 14, characterised in that said control is carried out as a function of at least one of the following parameters : confining pressure, excavator disc (7) torque, torque of the screw (10) for clearing out the spoil, rate of penetration of the drilling tool (1).
16. Method according to any one of Claims 13 to 15, characterised in that, at each device (24) generating foam under pressure, a constant flow rate of foam solution and a predetermined air pressure is provided.
17. Method of excavating earth in a confined atmosphere, where the pressure of the ground is balanced using a foam sent under pressure to the drilling tool (1), characterised in that the foam solution is conveyed through a pipe (25) and the air through another pipe (26) to the drilling tool (1) where said foam is generated under pressure by :

    at least one device (24), situated in the immediate vicinity of the rear bulkhead (8) of the chamber (9) for receiving the spoil, and the foam is injected under pressure into said chamber (9) ; and/or,

    at least one device (24), situated in the immediate vicinity of the hollow shaft (23) connected to the orifices (21) positioned on the excavator disc (7), and the foam is injected under pressure into said hollow shaft (23) ; and/or,

    at least one device (24), situated in the immediate vicinity of the screw (10) for clearing out the spoil, and the foam is injected under pressure into said screw (10) ; and/or,

    at least one device (24), situated in the immediate vicinity of the peripheral skirt (6) of the drilling tool (1), and the foam is injected under pressure towards the exterior through said skirt (6).
18. Method of excavating earth in a confined atmosphere, according to Claim 17, characterised in that one uses equipment according to any one of Claims 1 to 7, possibly fitted with a device according to any one of Claims 8 to 12.

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