LU85072A1 - METHOD FOR FORMING CONCRETE PILES AND NEW PREPARATORY PILE FOR THIS PROCESS - Google Patents

Description

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Concrete pile formation process and new preparatory pile for this process,

The present invention relates essentially to a process for forming concrete piles, as well as a new preparatory pile for this process.

It is well known (in particular according to the patent of the United States of America n ° 779 * 881) to form piles.in concrete by driving, into the ground, a preparatory pile comprising a barrel, as well as a base or 10 a pad removably attached to the bottom of the pile shaft, thereby forming an opening which, at least around the pile shaft, is filled with the concrete of which the permanent pile is to be made, the base then being detached from the barrel before removing the latter from the abovementioned opening.

Several improvements have been made to the process described in United States patent No. 779 * 881, these improvements being best illustrated by way of example in United States patent No. 3 * 851 * 485 on behalf of STED1NG · These improvements relate essentially to improved embodiments of the hopper intended to load the concrete into the opening, as well as to various configurations of the preparatory piles.

These known methods and apparatuses for forming concrete piles have a major drawback which consists in that, during the driving in of the preparatory pile, there is a movement of the ground giving rise to a "throttling" or a reduction of the diameter of the barrel according to well-known geotechnical principles with regard to shearing and displacement of the ground.

The object of the present invention is to find, for the first time, a solution preventing the "throttling" or the above reduction of the diameter h 2 * "of the barrel occurring during the driving of the preparatory pile, thus avoiding the drawback of known solutions for driving in.

According to the present invention, this solu-tion is carried out by a method for forming concrete piles, this method consisting in driving into the ground, a preparatory pile comprising a barrel and a base or a pad fixed removably at the bottom of the pile shaft, thus forming an opening 5 10 fill the opening, at least around the pile shaft, with the concrete of which the permanent pile is to be made and then detach the base of the pile before removing the drum by the opening, characterized in that it also consists in equipping the barrel of the preparatory pile, 15 at a height representing approximately four times the diameter of the barrel of the permanent pile above the base of the preparatory barrel, with casing with a diameter equal to that of the permanent drum, this casing being associated in its movement with the pile of the pile during the en-20 darkening of the preparatory pile, thus preventing shearing and displacement of the soil.

According to a particular embodiment, this casing may consist of a circular membrane fixed to the pile of the pile at discrete points around the latter in order to drive the concrete down during the driving in of the preparatory pile, this membrane then being removed through the opening together with the pile barrel.

In another embodiment, the casing may have a length equal to four times the diameter of the permanent pile barrel and, therefore, it extends downward from this height of about four times the diameter of the casing. bole of the permanent pile to come into contact with the base of the pile, this casing 35 being fixed to the bole of the pile to be removed together-

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3 ment with the latter through the aforementioned opening.

- According to another embodiment, the casing can consist of a concrete or asbestos / cement casing or it can also consist of a plastic pipe or a metal sleeve with a length equal to about four times the diameter of the permanent stake drum and extending downward from this height located at four times the diameter of the permanent stake drum above the base of the stake to contact that base. Preferably, according to this embodiment, this envelope is located in a corresponding cavity of the barrel of the preparatory pile, the latter having, in cross section, a profiled length equal to the diameter of the barrel of the permanent pile.

Likewise, the present invention relates to a new preparatory pile comprising a barrel and a base or a shoe removably attached to the lower part of the pile barrel, this pile being characterized in that it further comprises a height equal to about four times the diameter of the permanent pile barrel above the base of the preparatory pile, a casing with a diameter equal to that of the barrel of the permanent pile to be formed, this casing being arranged, relative to the pile of the pile, to be associated in its displacement with the latter 'during the driving in of the preparatory pile.

Accordingly, this tubing can be made in accordance with the truly preferred embodiments mentioned above.

The present invention will be illustrated with reference to the accompanying drawings in which; i ^ \! "4 Figure 1 is a schematic illustration of the shearing and displacement of the soil occurring during the driving in of the preparatory pile in accordance with known methods of the prior art which are illustrated by way of example in the United States patent United States of America No. 779 * 881; Figure 2 is an elevational view of the process of the invention according to the first embodiment of the preparatory pile of the invention; Figure 2a is a sectional view taken along the line Ila-IIa of FIG. 2; FIG. 3 is also an elevation view of the process of the invention according to a second embodiment of the preparatory pile of the invention. FIG. 3a is a sectional view taken along line III-IIIa of Figure 3. Figure 4 is an elevational view of the method of the invention in accordance with a third embodiment of the preparatory pile of the invention.

Referring to FIG. 1, the known method consists in driving into the ground 1 a preparatory pile 2 comprising a barrel 3 a base or a pad..4 removably fixed to the lower part 25 of the barrel of the stake, thus defining an opening 5,

This known method also consists in filling the opening 5) at least around the barrel 3 of the pile, with concrete 6, the “permanent pile of which must be formed, for example, using the concrete supply conduit 7 · According to this known method, the level of concrete is kept constant in the hole formed by the preparatory pile in order to fill the opening 5 as it is formed. When made of a hollow tube, the barrel 3 of the preparatory pile advantageously has holes 8 allowing the concrete to

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t t * * • 5 (ι l 4 move freely inside the pile shaft. The base is then detached before removing the shaft 3 from the pile.

According to this known process, during the installation of the preparatory pile 2, the base 4 or the plug of the preparatory pile 2 whose diameter D is necessarily equal to the diameter of the barrel of the permanent pile, there is a movement of the ground according to the arrows 10 represented in FIG. 1, the approximate limits of the movement of the ground being indicated by the outer line 12.

From FIG. 1, it can be seen that the lower limit of the movement of the ground is situated approximately at a depth equal to once the diameter of the base 4 of the pile, while this approximate limit of movement of the ground terminates at a height equal to four times the diameter of the base of the pile or of the permanent pile of the pile, since both the diameter of the base of the pile is that of the pile of the permanent pile to be formed.

This movement of the ground gives rise to a "throttling" effect or to a reduction in the diameter of the opening, that is to say a reduction in the diameter of the permanent pile.

This major drawback of the method known is avoided by the method of the present invention which will be! described below with reference to three really preferred embodiments which are illustrated in Figures 2 to 4 · 30 With reference to Figure 2 which shows the first embodiment of the preparatory pile of the invention, the pile preparatory 20 driven into the ground 1 of course also includes a barrel 21, j and a base or a removable pad 22 constituting J 35 the tip of the permanent pile in a known manner prior-

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! 6 ment and as illustrated by way of example in FIG. 1.

- In addition, according to the present invention, at a height approximately equal to four times the diameter of the barrel of the permanent stake above the base 22 of the prepa-5 stake, the latter also comprises a casing 24 of a diameter equal to that of the barrel of the permanent pile, this casing being associated in its displacement with the bole 21 at the course of the sinking of the preparatory pile 20, thus preventing shearing and displacement of the soil "

Preferably, as shown in FIG. 2, the casing 24 has a length equal to approximately four times the diameter of the barrel of the permanent pielt and, consequently, from this height situated at approximately four times the diameter above the base 22 of the pile, it extends downwards to come into contact with this base 22 "as shown clearly in FIG. 2, According to the embodiment illustrated in FIG. 2, the casing is fixed to the barrel 21 at discrete points 20 around the latter by means of protrusions 26 which are directed inward and which, in this case, are inclined. This fixing can be carried out according to any known technique and these internal protuberances can be, for example, 25 welded to the shaft 21 of the pile, -

According to the embodiment illustrated in FIG. 2, it can therefore be seen that the casing 24 prevents any "throttling" or any reduction in the barrel of the permanent pile, since both this casing 24 extends over a length representing four times the diameter of the permanent pile, thus preventing any movement of the soil during the driving in of the preparatory pile 20.

In the present embodiment, just as in the other embodiment illustrated in FIG. 3, the barrel 21 of the pile consists of a tube * comprising holes 28 allowing the concrete to

move freely inside this tube, since both the concrete is loaded outside the 5 preparatory pile 20, as indicated by arrow C

in Figure 2, the level of the concrete being indicated by the letters C * L. inside the temporary casing 30 which can be a hopper located in the opening made in the ground 1 · 10 Figure 2a shows that the shaft 21 of the pile comprises, in fact, a central tubular part 21a and radial extensions 21b which, in this case, are four in number, this number obviously being able to be lower or higher.

This tubing 24 which is fixed to the barrel 21 of the preparatory pile, will be removed with this barrel 21 when the latter is removed from the opening at the end of the process and after having detached, in a manner known per se, the base 22 of the pile constituting the tip of the stake per-20 manent. These removable assemblies between the barrel and the base of the pile are well known in the art and one can use, for example, those of the patent of United States of America n ° 779 * 881 or also the improvements described in the patent. of the United States of America No. 3 * 851 * 485 on behalf of STEDING.

Finally, it is also useful that the upper part 32 of the casing 24 which, in the present case, consists * of a hollow tube of roughly circular cross section, is inclined towards the inside, this inclined part leaving a free space. 36 between the barrel 21 of the stake and the upper part of the casing 24, this free space preferably representing approximately half the distance between the barrel 21 of the stake and the inner wall of the opening 34 * * 8 •

FIG. 3 represents another embodiment of the preparatory pile of the invention which, in this case, comprises the same barrel 21 as that illustrated in FIG. 2 with the same base 22. However, in this embodiment, the tubing is constituted by a circular membrane 40 which "preferably is fixed to the barrel 21 of the preparatory pile in the same way as the tubing 24 of the embodiment of Figure 2, in particular using protrusions 10 42 which are directed inwards and which are clinched as shown in the drawing · Likewise, the upper part 44 of the circular membrane 40 can advantageously be inclined towards the inside while leaving a free space 46 between the barrel 21 of the pile and 15 the upper part 44 of the casing 40 #

As shown in FIG. 3 * this circular membrane 40 constituting the casing is situated at a height representing approximately four times the diameter D of the barrel of the permanent pile above the base 22 of the preparatory barrel and, preferably, it ends exactly at this height and extends downward from this exact height to achieve the desired effect. The minimum length to achieve this desired effect is approximately half the diameter D of the permanent pile, this minimum length including the inclined portion 44 · In this embodiment, as in that of Figure 2 , thanks to the internal protrusions 42 * the concrete is driven down during the sinking

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30 of the preparatory stake.

Figure 4 illustrates a third embodiment of the preparatory stake of the invention. ,. In this case, the preparatory pile 50 comprises a barrel 51 which is shown in FIG. 4a and which must include a plate 51a on which two bars 51b, 51c ê 9 have been fixed perpendicularly and in alignment.

This barrel 51 also has holes 52 establishing free communication between the compartments defined between the plate 51a and the bars 51b, 51c, as will be clearly understood by examining FIG. 4a.

According to the present invention, this preparatory pile 50 also comprises a permanent envelope of concrete or of another resistant material 54 of a length approximately equal to four times the diameter D 10 of the barrel of the permanent pile, the lower part 54a of this pile coming into contact with the base 55 removably attached to the shaft 51 of the pile. This permanent envelope 54 is located inside a corresponding cavity 56 of the barrel 51 of the preparatory pile, the latter having, in this embodiment and outside the cavity 56, a profiled length in cross section practically equal to diameter D of the permanent pile, as shown clearly in Figure 4.

As a result, the permanent casing is practically locked "in the cavity 56 of the barrel 51 using the base 55 of the stake. Consequently, when the base 55 is detached from the pile of the barrel 51 and when the latter is removed, the permanent envelope 54 which, in this case, constitutes the casing of the invention, remains in the soil, thus preventing the movements of the latter both during the driving of the stake and subsequently.

Therefore, it is clear that one or the other of the three embodiments illustrated in Figures 2 to 4 is in accordance with the method of the invention "which has been described above.

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Claims (6)

2 · A method according to claim 1, 20 characterized in that the casing consists of a circular membrane fixed to the pile of the pile at discrete points around the latter in order to drive the concrete down during the sinking of the preparatory pile, this membrane then being removed jointly with the barrel of the pile, 3 * Method according to claim 1, characterized in that the casing has a length equal to approximately four times the diameter of the barrel of the permanent pile and s 'extends downwards from this height 30 situated at about four times the diameter of the permanent pile of the pile so as to come into contact with the base of the pile, this casing being fixed to the pile of the pile to be removed together with the latter, 4 · A method according to claim 1, 35 characterized in that the casing consists of an A è • ♦ 11 envelope of a resistant material with a length equal to about four times the diameter of the barrel of the permanent pile, while qu '' it extends downwards from this height located at about four times the diameter 5 of the permanent pile of the pile above the pile base, thus to come into contact with this base · 5 · Method according to claim 4, characterized in that the envelope is located in a corresponding cavity of the barrel of the preparatory pile which, in cross section, has a profiled length practically equal to the diameter of the barrel of the permanent pile, outside from the cavity, 6, New preparatory pile comprising a barrel and a base or a shoe removably attached to the lower part of this barrel, characterized in that it also comprises a casing (24 3 40, 54) situated at a height representing approximately four times the diameter of the permanent pile barrel above the base of the preparatory pile, this casing having a diameter equal to that of the permanent pile barrel and extinguished associated in its displacement with the pile of the pile during the insertion of the preparatory stake, thus preventing shearing and displacement, of the ground, 7 · Preparatory pile according to claims— 25 ~ tion 6, characterized in that the casing (40) consists of a circular membrane fixed to the barrel (21) of the pile at discrete points around the latter in order to expel the concrete downwards during the driving in of the preparatory pile, this membrane then being removed together with the barrel (21) of the pile, 8, Preparatory pile according to claim 6, characterized in that the casing (24) has a length equal to approximately four times the diameter of the barrel of the permanent pile, while it extends downwards from of this height located at about four ê \ • '12 I times the diameter of the drum of the permanent pile to come into contact with the base (22) of the pile, this casing (24) being fixed to the drum (21) of the pile to be removed together with the latter # 5 9 # Preparatory pile according to claim 6, characterized in that the casing (54) consists of an envelope made of a resistant material with a length equal to approximately four times the diameter of the barrel of the permanent pile and hearing downward at par-10 shot from this height located about four times the diameter of the barrel of the permanent pile above the base (55) of the pile, to come into contact with this base (55). 10 # Preparatory pile according to the resell - 15 cation 9, characterized in that the concrete envelope is located inside a corresponding cavity (56) of the barrel (52) of the preparatory pile, the latter having, in cross section, a profiled length roughly equal to the diameter of the barrel of the permanent pile, outside the cavity (56).