EP1146173A1 - Apparatus for producing drilled piles - Google Patents

Abstract

The machine, mounted on a preferably tracked platform (10), consists of a vertical mast (14) with an auger (22) having a hollow core and at least one spiral vane rotated by a drive head (20). An extension tube (28) is fitted to the top of the auger, and a plunger tube (36) goes inside it to deliver wet concrete from a feed pipe (32) into the hole made by the auger. An annular power cylinder (38) has one end joined to the top of the extension tube and its other end connected to the top of the plunger tube.

Description

The subject of the present invention is a machine for production of auger type bored piles.

More specifically, the invention relates to a machine which simultaneously allows the drilling of a cylindrical excavation in the ground and filling this excavation with grout or concrete to finally get a stake molded into the excavated soil.

In Figure 1 attached, there is shown a machine auger type drilling for making molded piles. This machine comprises a platform 10 preferably mounted on a track 12 on which is articulated a guide mast 14 which, in the position of work, is vertical. The mast 14 carries on one of its faces slides vertical 16 for guiding in translation a carriage 18. This carriage 18 carries a rotation head 20 which cooperates with a hollow auger 22 consisting of a hollow core 24 and at least one propeller-shaped blade 26. The rotation head 22 is used to rotate the auger 22, which causes it to sink into the ground by screwing and therefore the drilling the well. The auger 22 is hollow, it is possible after drilling the well, inject grout or concrete into it to build the stake as the auger exits the well.

For reasons of both congestion during movement of the machine and for construction reasons, the height of mast 14 and height H of auger 22 are always limited to a value of the order of 20 meters. However, in some sites, it is desirable to be able to drill and make molded piles whose depth is around 25 meters.

To allow the realization of such piles, we have already proposed add an extension tube 28 to the upper part of the auger 22 later called Kelly. The Kelly 28 of length h is joined in rotation and translation at the upper end of the auger and the end upper 28b of Kelly 28 is connected by a rotating joint 30 to a concrete supply line 32. We understand that thus the depth of the achievable stake is equal to H + h, which gives a depth of order 25 meters. It should be noted that the rotation head 20 can also cooperate well with the auger core 24 than with the Kelly 28.

A major drawback of such a system is the way whose concrete is introduced into the borehole to make the pile. The concrete comes out directly at the lower open end 24a of the hollow core auger. The displacement of this lower end 24a using the carriage 18 is delicate and the risk is that this lower end is not found above the concrete gradually filling the drilled well. This discontinuity is accompanied by a risk of localized landslide of the land in which the well has just been drilled and very significantly alter the mechanical strength of the pile which will thus be produced.

Furthermore, we know from French patent 2,566,813 in the name of Solétanche an auger drilling machine which avoids the disadvantage mentioned above. This hollow core auger is fitted with a tube mounted sliding in the hollow core of the auger, this tube being most often called dip tube. This tube is in position retracted into the auger when drilling the well and its lower end is moved to protrude from the lower end of the auger when it is raised to allow the injection of concrete into the drilled well. This technique ensures the good quality of the pile produced and notably the continuity of the concrete injection over the entire height of the drilling.

We understand that there is a real need to have a auger drilling machine for making molded piles which allows both the creation of piles of increased depth and obtaining high quality piles and in particular having a great continuity of its concrete structure.

An object of the present invention is to provide such drilling machine meeting these two requirements simultaneously.

• des moyens de guidage vertical ;
• une tête de mise en rotation mobile par rapport auxdits moyens de guidage vertical ;
• une tarière comportant une âme creuse et au moins une pale en forme d'hélice, ladite âme ayant une extrémité supérieure et une extrémité inférieure ouverte ;
• un tube prolongateur dont l'extrémité inférieure est solidaire de l'extrémité supérieure de l'âme de la tarière, ladite tête de mise en rotation coopérant avec ledit tube prolongateur pour la mise en rotation de l'ensemble constitué par la tarière et le tube prolongateur ;
• un tube plongeur monté coulissant dans l'âme creuse de la tarière et le tube prolongateur, le tube plongeur ayant une extrémité supérieure raccordée à une conduite d'alimentation en béton ;
• des moyens formant vérin ayant une première extrémité solidaire en translation de l'extrémité supérieure dudit tube prolongateur et une deuxième extrémité solidaire en translation de l'extrémité supérieure dudit tube plongeur ; et
• des moyens pour commander les moyens formant vérin, par quoi la position relative de l'extrémité inférieure dudit tube plongeur peut être modifiée par rapport à la position de l'extrémité inférieure de l'âme de ladite tarière.

To achieve this object, according to the invention, the drilling machine for producing bored piles comprises:

• vertical guide means;
• a rotating head movable relative to said vertical guide means;
• an auger having a hollow core and at least one propeller-shaped blade, said core having an upper end and an open lower end;
• an extension tube, the lower end of which is secured to the upper end of the auger core, said rotation head cooperating with said extension tube for rotation of the assembly constituted by the auger and the tube extender;
• a dip tube mounted to slide in the hollow core of the auger and the extension tube, the dip tube having an upper end connected to a concrete supply pipe;
• actuator means having a first end integral in translation with the upper end of said extension tube and a second end integral in translation with the upper end of said dip tube; and
• means for controlling the means forming a jack, whereby the relative position of the lower end of said dip tube can be modified relative to the position of the lower end of the core of said auger.

We understand that thanks to the fact that the hollow core of the auger is extended by an extension tube or Kelly, we can make piles of depth increased substantially the length of Kelly. We see also that the placement of a movable dip tube in the assembly formed by the hollow core of the auger and the Kelly allows benefit from all the advantages of a dip tube as regards the control of injecting concrete or grout into the drilled well to obtain the stake.

Preferably, the actuator means comprise a annular body surrounding the dip tube and integral in translation with the upper end of the extension tube and an annular movable part surrounding the dip tube and integral in translation with the end upper part of the dip tube.

We understand that thanks to the presence of the annular cylinder, it is possible to precisely control the position of the lower end of the dip tube relative to the lower end of the hollow core of the auger, which provides a high quality of concrete injection in the well drilled as the auger and Kelly despite the latter's presence. In addition, the use of a jack ring surrounding the dip tube avoids the introduction of a misalignment between the dip tube on the one hand and the Kelly and the auger on the other hand.

la figure 1 déjà décrite montre une machine de réalisation connue de pieux forés de profondeur accrue ;

la figure 2 est une vue en élévation de l'ensemble de la machine de forage selon l'invention ;

la figure 3a est une vue partielle de la figure 2 montrant le tube plongeur en position rentrée ;

la figure 3b est une vue analogue à la figure 3a montrant le tube plongeur en position sortie ; et

la figure 4 est une vue de l'ensemble de la machine à la fin de la réalisation du forage.

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:

FIG. 1, already described, shows a known machine for making bored piles of increased depth;

Figure 2 is an elevational view of the entire drilling machine according to the invention;

Figure 3a is a partial view of Figure 2 showing the dip tube in the retracted position;

Figure 3b is a view similar to Figure 3a showing the dip tube in the extended position; and

Figure 4 is a view of the entire machine at the end of the drilling.

Referring first to Figures 2 and 3, we will describe a preferred embodiment of the drilling machine.

In Figures 2, we find the platform 10 with its mast vertical guide 14 of the rotation head 20 as well as the auger hollow 22 whose hollow core 24 is connected in translation and rotation to the lower end 28a of the Kelly 28. The mechanical connection between the soul of the auger and the Kelly is of any kind suitable to allow the transmission of rotation and displacement of the rotation head 20 from the Kelly 28 to the core 24 of the auger 22. In FIG. 3b, we have represented by 34 these mechanical connection means.

According to the invention, the machine further comprises a tube plunger 36 which is slidably mounted in the hollow core 24 of the auger and in the Kelly 28. The dip tube 36 has a lower end 36a and an upper end 36b which is connected to the pipe 32 supply concrete or grout to the dip tube 36. As the best shown in Figure 3a, the upper end 28b of the Kelly is connected to an annular cylinder 38 which is interposed between the end upper 28b of the Kelly and the upper end 36b of the dip tube. This annular cylinder 38 which surrounds the upper part of the dip tube consists of an annular body 40 which surrounds the dip tube 36 and which is integral in translation with the upper end 28b of the Kelly but, preferably free relative to the latter in rotation. The body 40 of the jack ring 38 is connected to a pipe 42 for supplying fluid under pressure to control the jack 38. The latter also comprises an annular movable part 44 which surrounds the dip tube 36 and of which the upper end 44a is connected and secured to the end upper 36b of the dip tube by means of joining 46 which join the movable part of the cylinder in translation with the dip tube but which is preferably free to rotate. Of preferably also, the joining system 46 constitutes at the same time a rotating joint for the concrete supply line 32 of the dip tube 36.

We understand that thanks to the presence of the annular cylinder 40, it is possible for any position of the assembly constituted by the auger 22 and the Kelly 28 to define for the dip tube 36 a retracted position (figure 3a) in which the end 36a of the dip tube is set back by relative to the lower end 24a of the auger core and a position output shown in Figure 3b. In the first case, the cylinder body annular 40 is supplied with pressurized fluid, which causes the rise of the dip tube relative to the assembly constituted by the auger and Kelly. On the other hand, when the supply of the cylinder body 40 is interrupted, the dip tube is lowered relative to the assembly constituted by the auger and the Kelly and its lower end 36a protrudes out of the lower end 24a of the auger core. In this position, it is possible to control, by the dip tube, the injection of concrete in the well previously drilled by the auger 22. For this, as it is known per se, preferably near its lower end 36a, the side wall of the dip tube is provided with injection orifices such than 50. In the injection position, the orifices 50 are located at a controlled depth h 'below the lower end 24a of the auger, which keeps the injection ports 50 below of the free level of the concrete gradually filling the drilled well.

As is also known per se, it is possible to equip the lower end 36a with a drilling tool which facilitates the action auger when drilling the well. In this case, it can be interesting to provide that the dip tube 36 is coupled in rotation with the auger 22 and Kelly 28. This is made possible by the presence of the rotating joint 46 making the connection between the supply line 32 and the dip tube 36.

In Figure 4, the start of filling of the wellbore after completion. The lower end 36a of the tube plunger is arranged below the lower end of the auger 24a in such a way that the orifices 50 allow the injection of concrete in below the auger in the lower part 52 of the drilled well. Then the annular jack 38 holding the dip tube 36 in the extended position, the assembly constituted by the auger 22, the Kelly 28 and the dip tube 36 is generally reassembled via the rotation head 20. The length h 'between the end 24a of the hollow auger and the orifices Injection 50 provides a safety range to ensure that ports 50 remain well arranged below the concrete level during the ascent auger and dip tube.

We understand that the machine defined above allows on the one hand to realize bored piles of increased depth thanks to the presence of the Kelly 28 mounted at the upper end of the core auger and on the other hand we get a high quality of piles molded due to the presence of the dip tube 36 and the possibility of relative movement of the latter relative to the auger 22 thanks to the presence of the annular cylinder 38 which can be controlled independently of the position of the rotation head 20 and therefore of the position of the auger.

Claims (6)

Machine for making bored piles comprising: vertical guide means; a rotating head movable relative to said vertical guide means; an auger having a hollow core and at least one propeller-shaped blade, said core having an upper end and an open lower end; an extension tube, the lower end of which is secured to the upper end of the auger core, said rotation head cooperating with said extension tube for rotation of the assembly constituted by the auger and the tube extender; a dip tube mounted to slide in the hollow core of the auger and the extension tube, the dip tube having an upper end connected to a concrete supply pipe and a lower end provided with orifices; actuator means having a first end integral in translation with the upper end of said extension tube and a second end integral in translation with the upper end of said dip tube; and means for controlling the means forming a jack, whereby the relative position of the lower end of said dip tube can be modified with respect to the position of the lower end of the core of said auger between a first position in which the lower end of the dip tube is set back from the lower end of the auger core and a second position in which the orifices of the dip tube are outside the auger core. Machine according to claim 1, characterized in that said cylinder means comprise an annular body surrounding the dip tube and integral in translation with the upper end of the extension tube and an annular movable part surrounding the dip tube and integral in translation with the upper end of the dip tube. Machine according to any one of claims 1 and 2, characterized in that said vertical guide means comprise a mast and a carriage movable along said mast, said rotating head being integral with said carriage. Machine according to any one of claims 1 to 3, characterized in that the lower end of said dip tube is provided with a drilling tool. Machine according to any one of claims 1 to 4, characterized in that said dip tube has in its side wall at least one concrete outlet orifice, said orifice being offset relative to the lower end of said dip tube. Machine according to any one of claims 1 to 5, characterized in that the upper end of said dip tube is connected to said concrete supply pipe by a rotating joint.

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