Mortar feed box for a drill pipe, drill rig comprising such a box, and drilling method

Abstract

The invention provides a feed box (30) for a drill pipe (100, 11) whose wall has at least one hole for injecting mortar into the drill pipe, and whose body (32) has an internal chamber through which an upstream section (100) of the drill pipe passes, and a mortar feed fitting (46) for the internal chamber connected to a mortar feed source. The body (32) of the feed box (30) has another fitting (44) for supplying drilling fluid to the internal chamber, which is connected to a drilling fluid feed source, in particular water. The invention also provides a drilling rig equipped with such a mortar and drilling fluid feed box. The invention further provides a drilling method using such a drilling rig. Abstract figure: Fig. 1

Description

Title of the invention: Mortar feed box for a drill pipe, drill comprising such a box, and drilling method Technical field of the invention

[0001] The invention relates to a mortar feed box - also called a mortar box - for a drill tube whose wall has at least one hole allowing mortar to be transferred inside the drill tube.

[0002] The invention also relates to a drilling rig for drilling with the use of a drilling fluid and then injection of mortar by means of such a mortar box.

[0003] The invention further relates to a drilling method using such a drill. Technical background of the invention

[0004] In a known manner, particularly in the field of building and public works, for the execution of certain works, it is known to use a drill which is supplied with drilling fluid, for example water, during a drilling phase, then with a liquid or paste mixture generally called mortar or grout which is then injected progressively during the phase of raising the drill pipe.

[0005] For example, "solid" injection work involves injecting mortar into the ground through casing using an "upward pass." The most efficient technique is to drill, preferably with adjustable-frequency vibration assistance, using a drill pipe (in several sections connected by screw fittings) with an open drill bit. When the desired final drilling depth is reached, the mortar is injected into the drill pipe in successive passes via flexible "concrete" hoses.

[0006] To this end, in a known manner and along its vertical drilling axis, such a drilling rig comprises: - a superior drilling machine capable of rotating and vertically moving a drill pipe; - and a mortar feed box that is axially attached to the upper drilling machine, and in which the wall of the drill pipe has at least one hole inside the drill pipe, for injecting mortar - supplied by the mortar box -.

[0007] According to a known design, the mortar box comprises: - an internal annular axial chamber which is suitable for the drilling tube to pass through in rotation and in a watertight manner; - and a lateral mortar supply connection for the annular chamber which is suitable for connection to a mortar supply source, and which opens radially into the annular chamber.

[0008] For the supply of drilling fluid during the drilling phase, in particular water, it has been proposed to equip the drill rig with a water supply box - also called a water box - which is carried by the drilling machine and is thus arranged above the mortar box.

[0009] The drilling tube therefore extends vertically upwards from the level at which the mortar is injected, to the level at which the water is injected.

[0010] Such a design presents various disadvantages.

[0011] When the cut-off pressures are reached, the injected mortar rises in the drill tube above the mortar box, tends to wring itself out and then causes the formation of plugs at the lateral mortar supply connection.

[0012] Similarly, during drilling, this design requires that the flexible pipes connecting the mortar supply source to the side fitting be properly disconnected, otherwise the water washes away the mortar residue, which can also create many blockages.

[0013] The invention aims to remedy these drawbacks. Summary of the invention

[0014] The invention provides a feed box for a drill pipe, the wall of which has at least one hole for injecting mortar into the drill pipe, a mortar box having a body comprising: — an annular axial chamber which is suitable for being traversed in rotation and in a watertight manner by an upstream section of drilling pipe; — and a lateral mortar supply connection for the annular chamber which is suitable for connection to a mortar supply source and which opens radially into the annular chamber, characterized in that the body of the mortar box has another lateral drilling fluid supply connection to the annular chamber which is suitable for being connected to a drilling fluid supply source, in particular water, and which opens radially into the annular chamber.

[0015] According to other features of the power supply box: - upstream of each lateral connection supplying the annular chamber, the supply box is associated with a flow opening and closing control device; - the annular chamber is axially delimited by at least two opposing seals, upper and lower, capable of cooperating with the wall of said upstream section of drill pipe; - each sealing gasket is housed in an internal radial groove of the mortar box body; - the lateral mortar supply connection of the annular chamber has an inlet which is suitable for being connected to the mortar supply source or for being closed by a removable sealing plug during a drilling phase; - during a mortar injection phase through the drilling tube, to prevent mortar from rising through the lateral drilling fluid supply connection, a non-return valve is associated with the lateral drilling fluid supply connection of the annular chamber; - the upstream section of the drill pipe comprises successively an upper part comprising a flange for fixing to a drilling machine, an intermediate part in which at least one hole is formed allowing mortar to be injected inside the drill pipe, and a lower part for connecting to a drill pipe.

[0016] The invention also proposes a drilling rig for drilling with the use of a drilling fluid and mortar injection, which, along its vertical drilling axis, comprises: - a superior drilling machine capable of rotating and vertically moving an upstream section of drill pipe; - and a power supply box according to the invention which is axially attached to the upper drilling machine, drilling machine in which the wall of the upstream section of the drill pipe has at least one hole for injecting mortar into the drill pipe.

[0017] The invention further proposes a drilling method using a drill according to the previous invention comprising a feed box according to the invention, characterized in that it comprises steps consisting of: - seal the inlet of the lateral connection supplying the annular chamber with mortar using said plug: - supply the annular chamber with drilling fluid through the lateral drilling fluid supply connection; - proceed with drilling; - connect the inlet of the side mortar supply fitting to the mortar supply source; - proceed with the gradual raising of the drilling machine and the drill pipe by injecting mortar through the drill pipe as it is raised. Brief description of the Figures

[0018] [Fig.1] - [Fig.1] is a perspective view which represents in a simplified way a drill equipped with an example of an embodiment of a feed box according to the invention, the drill being illustrated in a vertical position corresponding to the final drilling depth and the beginning of the mortar injection phase;

[0019] [Fig.2] - [Fig.2] is a perspective view which represents the power supply box according to the invention;

[0020] [Fig.3] - [Fig.3] is a side view of the power supply box illustrated in [Fig.2]

[0021] [Fig.4] - [Fig.4] is a cross-sectional view of the power supply box according to the invention by the axial plane 4-4 of [Fig.3];

[0022] [Fig.5] - [Fig.5] is a perspective view of the upstream section of the drill pipe associated with the feed box according to the invention;

[0023] [Fig.6] - [Fig.6] is a cross-sectional view of the feed box similar to that of [Fig.4] on which the upstream tube section of [Fig.5] is also shown in the functional axial position it occupies relative to the feed box;

[0024] [Fig.7] - the [Fig.7] is a hydraulic diagram illustrating the control and operation of the drill of the [Fig.1]. Detailed description of the figures

[0025] For the description of the invention and the understanding of the claims, the vertical orientation will be adopted along the vertical axis V.

[0026] In the description that follows, identical, similar or analogous elements will be designated by the same reference numerals.

[0027] Figures show an upstream section 100 of a vertical axis V drill pipe whose upper part 12 is closed axially upwards and is formed into a flange 18 allowing its attachment to a complementary part 111 of a drilling machine to allow in particular the rotational drive in both directions and the axial displacement in both directions of the upstream section 100.

[0028] The upstream section 100 also includes a lower part 16 allowing the connection by screwing of another section 11 of drilling tube to the upstream section 100. For this purpose, the lower part 16 is externally threaded.

[0029] Finally, the upstream section 100 includes an intermediate part 14 comprising in particular at least one hole allowing mortar to be injected inside the drilling tube.

[0030] By way of non-limiting example, the intermediate part 14 here comprises a plurality (three) of holes 20 distributed angularly.

[0031] According to the teachings of the invention, the upstream section 100 is associated with a "double" feed box 30 which provides both a mortar box function and a drilling fluid box function such as water.

[0032] As can be seen in figures 2 to 4 and 6, the supply box 30 comprises a body 32 of generally tubular shape with vertical axis V which is suitable to be traversed axially by the upstream section 100 (See [Fig.6]).

[0033] In its internal cylindrical face 34, the body 32 delimits a central annular chamber 36 which is delimited radially towards the axis V by the portion opposite the wall of the upstream section 100 (See [Fig.6]).

[0034] Axially above the annular chamber 36, the internal cylindrical face 34 has a pair of upper radial grooves 38, each of which is suitable for housing a sealing gasket (not shown), in particular a lip seal(s) which cooperates with the portion opposite the wall of the upstream section 100.

[0035] Similarly, axially below the annular chamber 36, the internal cylindrical face 34 has a pair of lower radial grooves 40, each of which is suitable for housing a sealing gasket (not shown), in particular a lip seal(s) which cooperates with the portion opposite the wall of the upstream section 10.

[0036] Thus, the annular chamber 36 is a chamber delimited in a watertight manner at its two opposite axial ends.

[0037] For its attachment to a drilling machine 10, the body 32 of the power supply housing 30 here has two diametrically opposed lateral flanges 42.

[0038] The body 32 of the power supply housing 30 has two radial ports 43 and 45 which are arranged vertically so as to each open into the annular chamber 36.

[0039] The radial orifice 43 is equipped with a lateral fitting 44 for supplying the annular chamber 36 with drilling fluid, while the radial orifice 45 is equipped with a lateral fitting 46 for supplying the annular chamber 36 with mortar.

[0040] The two side fittings 44 and 46 are fixed by welding onto the body 32 of the power supply housing 30. side fittings 44 and 46 are for example of different dimensions with fitting 46 having a larger diameter for mortar supply.

[0041] Each lateral supply fitting 44, 46 has an inlet 48, 50 respectively which is suitable for being connected to a conduit 52 or a flexible hose 54, which is connected to a source 58, 60 (See [Fig.7]) of supply to the fitting 44, 46 of drilling fluid and mortar respectively.

[0042] The inlet 50 of the side fitting 46 for mortar supply of the supply box 30 is suitable for being connected in a removable manner to the flexible hose 54 or to a sealing plug (Not shown).

[0043] As shown in [Fig. 7], upstream of each lateral fitting 44, 46 the box 30 mortar supply is associated with a flow opening and closing control device, and for example a hydraulically controlled valve 62, 64.

[0044] During the mortar injection phase, to prevent mortar from rising through the lateral fitting 44 for supplying drilling fluid, a non-return valve 66 is associated with the fitting.

Claims

Demands

1. Feeding box (30) for a drill pipe, the wall of which has at least one hole (45) for injecting mortar into the drill pipe, feeding box (30) having a body (32) comprising: — an internal annular axial chamber (36) which is capable of being traversed in rotation and in a sealed manner by an upstream section (100) of drill pipe; — and a lateral mortar supply connection (46) for the annular chamber (36) which is suitable for being connected to a mortar supply source (60) and which opens radially into the annular chamber (36), characterized in that the body of the supply box (30) includes another lateral drilling fluid supply connection for the annular chamber (36) which is suitable for being connected to a drilling fluid supply source, in particular water, and which opens radially into the annular chamber (36).

2. Supply box (30) according to the preceding claim, characterized in that, upstream of each lateral connection (44, 46) supplying the annular chamber (36), the supply box (30) is associated with a flow opening and closing control device (62, 64).

3. Feed box (30) according to claim 1 or 2, characterized in that the annular chamber (36) is axially delimited by at least two opposing seals, upper and lower, adapted to cooperate with the wall of the upstream section (100) of drill pipe.

4. Feed box (30) according to the preceding claim, characterized in that each sealing gasket is housed in an internal radial groove (38, 40) of the body of the feed box (30).

5. Feed box (30) according to any one of claims 1 to 4, characterized in that the lateral mortar feed connection (46) of the annular chamber (36) has an inlet (48) which is suitable for being connected to the mortar feed source (60) or for being closed by a removable sealing plug during a drilling phase.

6. Feed box (30) according to any one of claims 1 to 5, characterized in that, during a phase of mortar injection through the drill pipe, to prevent mortar from rising through the lateral fitting (44) for supplying drilling fluid, a non-return valve (66) is associated with the lateral fitting (44) for supplying drilling fluid to the annular chamber (36).

7. Feed box (30) according to any one of the preceding claims, characterized in that the upstream section (100) of drill pipe successively comprises an upper part (12) having a flange (18) for fixing to a drilling machine (10), an intermediate part (14) in which at least one hole (36) is formed for injecting mortar into the drill pipe, and a lower part (16) for connecting to a drill pipe.

8. Drilling rig, for drilling with the use of a drilling fluid and injection of mortar and which, along its vertical drilling axis (V), comprises: - an upper drilling machine (10) capable of rotating and vertically moving an upstream section (100) of drill pipe; - and a feed box (30) according to any one of the preceding claims which is axially attached to the upper drilling machine (10), drilling rig in which the wall of said drill pipe has at least one hole (20) for injecting mortar into the inside of the drill pipe.

9. A drilling method using a drill according to the preceding claim comprising a feed box (30) according to claim 5, characterized in that it comprises steps consisting of: - plugging the inlet of the lateral feed fitting of the annular chamber (36) with mortar by means of said plug; - feeding the annular chamber (36) with drilling fluid through the lateral feed fitting of drilling fluid; - carrying out the drilling; - connecting the inlet of the lateral feed fitting of mortar to the source of mortar supply; - proceed with the gradual raising of the drilling machine and the drill pipe by injecting mortar through the drill pipe as it is raised.

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