EP0900913A1 - Drillstring - Google Patents

Abstract

The drilling string consists of a number of rods (16) joined by male and female couplings. Each rod has an axial channel (34) running its whole length, with the rods fitted together so that the channels on adjoining rods lie at 180 degrees to one another. The channels contain flexible pipes (20,22) which are used to carry a fluid such as mortar, water or air, the width of the channels being at least equal to the outer diameter of the pipes.

Description

The present invention relates to a drill string.

In the field of building and public works, there is a certain number of situations in which it is necessary to be able to have a train hollow rods to allow drilling and injection of liquid materials such as only grout.

This is particularly, but not exclusively, the case of implementation a rotary jet soil treatment process, which is used for the production of reinforcing elements in the form of columns and that of screens sealing in the mass of permeable ground.

Such a process is described in detail in French Patent No. 2,697,551. It is therefore not necessary to describe it in more detail. Just call back that for the implementation of this process, a device is usually used comprising a cement grout production plant supplying grout one or more pumps connected via a rotating joint to a train of rods introduced into the borehole where the jet treatment must be carried out. The drill string can be driven in translation and in rotation thanks to a hydraulic rotary head, by tightening the upper end of the rod train which is itself mounted preferably on a drilling slide. In general, the pump (s) deliver the fluid most often consisting of a grout (consisting of a mixture of water and cement or water and binder) or water with pressures on the order of 200 to 700 bars or more.

As is well known, the drill string consists of rods having the form of unitary tubular sections connected to each other and provided with appropriate seals, each section can be formed of a single tube in the case of a single jet or multiple coaxial tubes in the case with a double or triple jet. We understand that in this process, the drill string fulfills the double function of allowing movement in drilling of the rotary jets and to transmit fluids from the production station to ejection nozzles, these fluids can be a grout, air or water.

In addition, a drilling tool can be provided below the nozzles. used to make the jets at the lower end of the drill string for carry out the drilling in which the treatment will be carried out.

In practice, the jet treatment is started by placing the device jet at the bottom of the borehole and driving the drill string in a movement of rotation and translation towards the borehole head until a column of land treated at the desired height. We understand that, during this operation, the drill string during its ascent protrudes from a height more and more larger above the surface of the soil in which the treatment is applied. This is not a disadvantage when the work is carried out in normal site conditions, i.e. under conditions where the height above the ground is not limited or at least allows the complete ascent of the drill string.

However, there are situations in which the available height above the borehole is reduced for example due to a height ceiling room, narrow working room, etc., so that there is no in the axis of the drilling of the place necessary to go up the desired length of drill string. We understand that, in this case, it is necessary to dismantle during treatment rods as they rise.

However, such a dismantling has the disadvantage that it creates the risk that grout circulating in the tubular elements constituted by the rods penetrates in the air or water supply channel of these rods, which, when the treatment is resumed, damages or clogs the grout ejection nozzles. In addition, during disassembly, we are forced to stop the supply of fluids and in particular of the train grout rods and there is a risk that there would be an untimely return of air ejected from clogging the nozzles.

In order to remedy this drawback, it has been proposed in the patent French already mentioned to separate the drill string function proper from the function of channeling the grout supply of the ejection nozzles. In this patent, it is planned to use flexible pipes connected to the ejection head and arranged outside the drill string. This solution effectively solves the problem posed since, the grout not circulating in the drill string, it is easy to dismantle the rods as they rise.

This solution is satisfactory. However at least in some cases the presence of flexible pipes in the drilling outside the drill string makes as these flexible pipes are not protected, they may therefore be worn or even perforated.

An object of the present invention is to provide a drill string for drilling which, in particular in the case of the implementation of a process for injecting grout, allows easy disassembly of the drill string without interrupting the supply in grout of the ejection nozzles, while avoiding the drawbacks mentioned above.

To achieve this object, according to the invention, the drill string comprising a plurality of rods all having the same axial recess, each rod comprising at a first end a male end and at a second end a female end, the male end of a first rod being able to cooperate with the female end of an adjacent rod, is characterized in that each rod has in its wall surrounding said axial recess a slot extending over its entire length, the male and female end pieces being arranged in such a way so that when several rods are assembled, the slit of a rod, relative to the common axis of the rods, or disposed substantially at 180 ° relative to the slots of the two adjacent rods, said train further comprising at least one pipe disposed in the axial recesses of said rods, the width of the slot of each rod being at least equal to the diameter of said pipe.

We understand that, thanks to the particular shape given to each rod of the drill string, the lines for the various liquids which must be ejected the base of the drill string circulates in hoses arranged inside the rods thus ensuring the protection of these hoses. We understand, however, that, because that each rod has a slot over its entire length, it is possible to proceed to the removal and disassembly successively of each rod without this disrupts the flow of grout in the hoses. We also see that the alternation of the rods having slots arranged at 180 ° ensures a very good guiding the hoses inside the axial recess defined by the succession of rods and the mechanical protection of these hoses. However, disassembly successive rods is easy since the hoses can pass through the slot provided in each rod.

According to a preferred embodiment, each male or female end piece has an axial recess extending that of the rod and a surrounding wall said recess, said wall having notches extending parallel to the axial direction of the rod, one of said notches extending the slot of the rod, said notches being separated by protruding portions of the wall, the notches of a male or female end of a rod corresponding to the portions in projection of a female or male end of an adjacent rod, whereby the faces lateral notches parallel to the axial direction of a male end and a female tip cooperate with each other when a rotational movement is applied to the drill string, and the faces of the protruding portions and the notches of a nozzle male and female tip cooperate with each other under the effect of a push downward vertical applied to the drill string.

• la figure 1 est une vue d'ensemble d'une installation de traitement du sol par jet rotatif utilisant un train de tiges conforme à l'invention ;
• la figure 2 est une vue simplifiée en élévation d'un train de tiges conforme à l'invention ;
• la figure 3 est une vue en coupe horizontale selon la ligne 3-3 de la figure 2 ;
• les figures 4 et 5 sont des vues en perspectives respectivement de l'embout mâle et de l'embout femelle d'une tige ;
• la figure 6 est une vue en coupe horizontale de l'embout mâle d'une tige présentant une première orientation de fente ;
• la figure 7 est une vue en coupe horizontale de l'embout mâle d'une tige présentant la deuxième orientation de fente ; et
• la figure 8 est une vue en coupe horizontale d'un embout mâle et d'un embout femelle connectés entre eux.

Other characteristics and advantages of the invention will appear better on reading the following description of several embodiments of the invention given by way of non-limiting examples. The description refers to the appended figures, in which:

• Figure 1 is an overview of a soil treatment installation by rotary jet using a drill string according to the invention;
• Figure 2 is a simplified elevational view of a drill string according to the invention;
• Figure 3 is a horizontal sectional view along line 3-3 of Figure 2;
• Figures 4 and 5 are perspective views respectively of the male end and the female end of a rod;
• Figure 6 is a horizontal sectional view of the male end of a rod having a first slot orientation;
• Figure 7 is a horizontal sectional view of the male end of a rod having the second slot orientation; and
• Figure 8 is a horizontal sectional view of a male endpiece and a female endpiece connected together.

In FIG. 1, there is shown in vertical section, in a simplified manner, an installation for the implementation of the soil treatment process by jet of grout. In the borehole 10 is arranged a tubular rod train 14 constituted by the rods 16a, etc., 16n. The lower rod 16n has its lower end secured to a grout ejection head 18, this ejection head possibly also possibly be equipped with a drilling head used to carry out drilling 10. Inside the axial passage defined by the tubular rods 16 are arranged conduits flexible such as 20 and 22 for supplying the ejection nozzles especially in grout in water or air. Advantageously, the ends of these flexible tubes 20 and 22 can be wound on storage drums such than 24 arranged on the ground surface. The installation also includes a head 26 for rotating the rod train and a slide 28 for guiding the rods in their part projecting out of the borehole 10.

In Figure 2, there is shown schematically drill rods 16 assembled together. These tubular rods comprise an upper male end piece 30 and a female lower end piece 32. It is thus possible to make the mechanical connection between two consecutive rods 16 and thus constitute the entire set of rods. According to an essential characteristic of the invention, as will be explained in more detail later, the rods of course comprise an axial recess 34 which communicates with the outside by a slot 36 whose width e is substantially equal to the dimension e 'of the recess 34. According to another characteristic of the invention, the male 30 and female 32 ends are produced in such a way that, after assembly, the slots 36 of the rods are arranged alternately at an angle of 180 ° by relative to the common axis XX 'of the drill string. For example, in Figure 2, for the rod 16b, the slot is directed towards the front of the figure, while for the rod 16a, the slot is directed towards the rear of the figure.

The axial recess of each rod is intended to receive the pipes 20 and 22.

Preferably, the current part of each rod 16 is constituted by a folded sheet 38 which defines the axial housing 34 as well as the slot 36.

As shown more clearly in Figures 4 and 5, the end caps respectively male 30 and female 32 are solid parts welded to ends of the current part of the rod 16.

If we consider the male end piece 30, it has a massive part 40 provided with the slot 42 extending the slot 36 of the rod and of a connection part 44. In the case of the male end piece 30, this connection part comprises, like the shows better in Figure 6 two recesses 46 and 48. If we consider the different areas of the connection part 44 with respect to the axis XX 'of the train rods, there is a first projecting area 50 opposite to an area forming a slot 52 which extends the slot 42. The remaining parts constitute the notches 46 and 48 which are diametrically opposite as well as two projecting portions, the portion 54 being connected to portion 50 and portion 56 being isolated. Figure 5 shows the female end piece which has exactly the same shape as the male end piece. The only difference is that the projecting parts of the male end are provided at their upper end with chamfers such as 60 to facilitate assembly of rods.

The female end piece 32 therefore has exactly the same system notch and projecting parts. If we consider the male and female tips rods intended to be associated with a given rod and whose orientation of the slot is arranged at 180 °, we find the arrangement shown in Figure 6.

Regarding the male and female ends 63 of the rods intended for present the opposite slot orientation, they present an inversion of the parts in projection and notches as shown in Figure 7.

We understand that the engagement of the male end of a rod and the female end of the adjacent rod ensures on the one hand the rotational connection of these two rods by the cooperation of the vertical faces such as 62 of the notches and on the other hand the connection of these two rods in the direction of insertion by the cooperation of the bearing surfaces such as 64 of the notches and parts in projection, these faces being perpendicular to the axis of the rods, that is to say horizontal.

Preferably, as shown for example in Figure 6, the vertical side faces 62 ₁ and 62 ₂ of the notches 46 and 48 are arranged in the same plane containing the axis XX 'of the rod. This arrangement of course promotes the transmission of torque between the rods. Due to the presence of the slots in the rods, the other vertical lateral faces 62 ₃ and 62 ₄ of the notches cannot comply exactly with this provision. They approach it. As can be seen in FIG. 6, the faces 62 ₃ and 62 ₄ are arranged substantially in the same plane, but this plane is slightly offset with respect to the axis XX '.

More generally, efforts are made to ensure that the lateral faces corresponding notches are substantially arranged in the same plane containing the axis of the rod.

To ensure the necessary mechanical connection between the rods during their rise, there is provided in each female endpiece a movable axis 70 and 72 which can be engaged in corresponding bores 74 and 76 for the female end piece and 78 and 80 for the male end. We understand that, when axes 70 and 72 are engaged and locked in the different "horizontal" bores, securing the rods is ensured in the direction of lifting said rods.

Figure 8 shows the assembly of the male end of a rod and the female end of the adjacent rod. We see that at this level the axial recess is fully surrounded by the combination of male and female tips, which ensures maintaining the hoses 90 and 92 in the rods. However, as soon as the stems are uncoupled, the slot allowing the extraction of the hoses is recreated.

Claims (6)

A drill string comprising a plurality of rods having all the same axial recess, each rod having at one end a male end piece and at a second end a female end piece, the male end piece a first rod being able to cooperate with the female end of a rod adjacent, characterized in that each rod has in its wall surrounding said axial recess a slot extending over the entire length, the male end fittings and female being arranged in such a way that when several rods are assembled, the slot of a rod, relative to the common axis of the rods, is disposed substantially 180 ° to the slots of the two adjacent rods, said train comprising at in addition to at least one pipe disposed in the axial recesses of said rods, the width of the slot of each rod being at least equal to the diameter of said rod conduct. Rod string according to claim 1, characterized in that each male or female end piece has an axial recess extending that of the rod and a wall surrounding said recess, said wall having notches extending parallel to the axial direction of the rod, one of said notches extending the slit of the rod, said notches being separated by portions protruding from the wall, the notches of a male or female end of a rod corresponding to the protruding portions of a female or male end of a rod adjacent, whereby the lateral faces of the notches parallel to the direction axial of a male end piece and a female end piece cooperate with each other when rotational movement is applied to the drill string, and the faces of the portions in protrusion and notches of a male end piece and a female end piece cooperate between them under the effect of a downward vertical thrust applied to the drill string. Rod string according to claim 2, characterized in that each male or female end piece has two notches and therefore two portions in protrusion. Rod string according to claim 3, characterized in that the corresponding side faces of the notches are arranged in the same plane substantially containing the axis of the rod. Rod train according to any one of claims 2 to 4, characterized in that each male or female end piece includes means movable rod locking relative to adjacent rods according to the direction of the common axis of said rods. Rod string according to claim 5, characterized in that said locking means comprise pins mounted sliding in bores in said end pieces, the axes of said bores being orthogonal to the longitudinal axis of the rod.

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