Steel pile adapted to be driven into the ground and method for driving a steel pile

Description

[0001] The invention relates to a steel pile as defined in the preamble of claim 1.

[0002] A pile of this type is disclosed in document EP 0 342 138.

[0003] With this well-known steel pile a passage system comprising a horizontally extending passage with downwardly directed passages extending therefrom is cut in a central web of the pile body, said passage system being covered on either side of the web by said two strip portions, with the exception of the lower end portions of said downwardly extending passages. The lower end portions of the downwardly extending passages constitute transverse openings through the central web, through which, when driving the pile into the ground, fluid under pressure may enter laterally into the ground so as to improve lubrication of the pile surface on both sides and thereby facilitate driving of the pile into hard (rocky) grounds. Driving of the pile is taking place by hammering.

[0004] The particular manner of providing a fluid passage with the well-known steel pile above referred to result in a rather complicated pile foot.

[0005] The present invention aims at providing an improved pile, which is particularly suitable for driving into the ground by vibration.

[0006] According to the invention this aim is achieved by the features defined in the second part of claim 1.

[0007] As compared with the well-known steel pile described hereinabove the steel pile according to the invention has a "fluid injecting" pile foot that can be easily obtained by having said two strips extend below the lower edge of the web of the pile body.

[0008] The invention also relates to a method for driving a steel pile of the type above referred to into the ground by vibration, as defined in the preamble of claim 2.

[0009] The method according to the invention is characterized by the features mentioned in the second part of claim 2.

[0010] Due to the fact that the fluid under pressure leaves the collecting and distributing passage exclusively in a substantially downward direction, driving of the steel pile vibration will be accompanied by an enhanced process of bringing the ground immediately below the lower terminal end of the steel pile body into a fluidized state, which facilitates the penetration of the pile into the ground quite substantially. Moreover the controlled supply of fluid will keep the ultimate hold between the pile body and the surrounding soil substantially unaffected.

[0011] It is to be noted, that document GB 398 354 discloses a sheet pile, comprising a central fluid supply conduit that discharges in a pointed arch-shaped lower foot end of the pile. With this pile there is no horizontal fluid collecting and distributing passage from which fluid may enter into the ground during pile driving. With this well-known pile the fluid supply conduit may easily get blocked.

[0012] Furthermore, as an alternative, the invention provides a method as defined in claim 3.

[0013] As to the type of steel pile used with this alternative method reference is made to DE-A 35 42 313, which discloses a steel pile with a fluid discharging tube along the lower terminal edge of the pile body, from which tube a fluid, more particularly bentonite, is discharged through openings, which are directed upwardly and laterally. Moreover the well-known steel pile is said to be driven into the ground by vibration.

[0014] The steel pile used with the alternative method of the invention distinguishes from this well-known pile in that the fluid discharge openings are all directed in the substantially downward direction.

[0015] It is further to be noted that on page 11, lines 22-25 of DE-A-35 42 313 mention is made of the possibility of discharging water under high pressure from the lower end of the pile body so as to bring the ground in a fluidized state.

[0016] The invention will be hereinafter further described by way of example with reference to the accompanying drawings in which:

Fig. 1 is a perspective view, showing two sheet piles for use in a method according to the present invention in mutual engaging relationship;

Fig. 2A is a vertical cross-sectional view through the lower edge of a sheet pile, according to the line II-II in Fig. 1 and

Fig. 2B is a cross-sectional view of a steel pile according to the present invention;

Fig. 3 shows a pipe-shaped form of a steel pile for use in a method according to the invention and

Fig. 4 is a perspective view of a steel pile for use in a method according to the invention in the form of a profile.

[0017] With reference to Fig. 1 two sheet piles 1 and 2 of a well-known trapezoid shape are diagrammatically shown. The sheet pile 1 has already been driven at the desired depth whereas the sheet pile 2 has to be driven further into the ground.

[0018] The sheet piles 1 and 2 have their longitudinal edge formations in mutual engaging relationship as is well known in the art. A relatively thick-walled steel tube 3 is attached, e.g. by welding, along the lower edge of the sheet piles 1 and 2. Said tube 3 is provided with downwardly facing discharge openings 4. In the example shown in Fig. 1, the tube 3 is following the profile of the lower edge of the respective sheet pile and is connected to the lower end of a supply tube 5, which extends upwardly along the body of the respective sheet pile.

[0019] In operation the supply tube 5 is connected with its upper end to a source of pressurized fluid (liquid), which is supplied through the supply tube 5 to the tube 3 along the lower edge of the sheet pile entering into the ground and is discharged from the latter tube through said openings 4.

[0020] While driving the sheet pile, by vibration or pushing, the fluid supply is controlled such that the discharging fluid brings the soil immediately below the lower edge of the sheet pile in a fluidized state. Depending on the type of the ground the required fluid pressure may vary e.g. between 10 and 100 bar.

[0021] In the example of Fig. 1 a central supply tube 5 is used and the tube 3 may have its ends closed. The tube 3 could also be connected to a supply conduit provided in the so-called "lock space" along the free longitudinal edge formation (to the right in Fig. 1), which supply conduit would have to be removed prior to driving the next sheet pile.

[0022] In the steel pile according to the invention shown in Fig. 2B, a downwardly open collecting or pressure passage 3' is provided, which is confined by two strips 6 that are attached, e.g. by welding, on both sides of the lower portion of the respective sheet pile and is connected with a fluid supply conduit (5'). For the purpose of strengthening the strips 6 may be interconnected by bridging portions at regularly spaced locations.

[0023] In the embodiment shown in Fig. 3 the steel pile is in the form of a steel pipe 10, having a substantially circular tube 11 of reduced diameter fastened, e.g. welded, to its lower edge. The circular tube 11 is provided with downwardly directed discharge openings 12. The tube 11 may be in the form of two sections, which each cover a half of the circumference of the pipe 10 and are each connected with one end to the lower end of a supply conduit 13, that extends along the inner side of the pipe 10 upwardly, whereas the two sections 11a are closed at the opposite ends.

[0024] In operation the supply conduits 13 are connected with their upper ends to a source of pressurized fluid (liquid), which is supplied through the supply conduits 13 to the tube sections 11a along the lower edge of the pipe 10 entering into the ground. Driving of the pipe 10 is preferably effected by vibration. Especially with pipes of larger diameters less vibrating energy will be required for entering the pipe into the ground. It will be understood that a plurality of tube sections each connected to a supply conduit 13, may be used.

[0025] In the embodiment shown in Fig. 4 the steel pile is in the form of a H-profile 20, the lower edges at the foot of the profile being provided with fluid injection tubes 21 having discharge openings 22. In this example the injection tubes 21 are supplied with fluid through two supply conduits 23 on either side of the web of the H.

[0026] The profile shown in Fig. 4 may e.g. be used for making so called "Berliner" walls, with which between individual H-profiles horizontally extending beams of wood can be inserted.

Claims

1. A steel pile, adapted to be driven into the ground and having along at least part of its lower terminal edge a thickened edge formation which comprises two strip portions (6) positioned on either side of a web portion of the pile body and forming, together with said web portion, a fluid collecting and distributing passage (3') which is connected with a fluid supply conduit (5') that extends along the pile body downwardly, from which passage fluid under pressure may enter into the surrounding soil during pile driving, characterized in that said two strip portions (6) extend downwardly beyond the respective web portion, so as to form said passage as a substantially downwardly directed channel between said two strip portions below the lower edge of said web portion.

2. A method for driving a steel pile according to claim 1 into the ground by vibration, while simultaneously causing a fluid to discharge from the fluid collecting and distributing passage (3') along the lower edge of the pile body, characterized in that the fluid is caused to discharge exclusively substantially vertically downwardly and controlled to be just enough to bring the soil immediately below the lower end of the pile body into a fluidized state.

3. A method for driving a steel pile into the ground by vibration, wherein the pile is of the type comprising a pile body with a fluid discharge tube (3) along part of its lower terminal edge and with the fluid discharge openings (4) of said discharge tube being all directed substantially downwardly, the method comprising the step of causing a fluid to discharge through said substantially downwardly directed discharge openings and controlling the fluid supply to be just enough to bring the soil immediately below the lower terminal end of the pile body into a fluidized state.

Ansprüche

1. Stahlpfahl, der zum Eintreiben in den Boden ausgebildet ist und entlang mindestens einem Teil seines unteren Endrands eine verdickte Randausbildung hat, die zwei Streifenbereiche (6) aufweist, die an beiden Seiten eines Stegbereichs des Pfahlkörpers positioniert sind und gemeinsam mit dem Stegbereich einen Fluidsammel- und -verteilerkanal (3') bilden, der mit einer Fluidzuführleitung (5') verbunden ist, die entlang dem Pfahlkörper abwärts verläuft, wobei während des Eintreibens des Pfahls Druckfluid aus dem Kanal in das umgebende Erdreich eintreten kann, dadurch gekennzeichnet, daß die beiden Streifenbereiche (6) nach unten über den jeweiligen Stegbereich hinaus verlaufen, um den Kanal als einen im wesentlichen abwärts gerichteten Kanal zwischen den beiden Streifenbereichen unterhalb des unteren Rands des Stegbereichs zu bilden.

2. Verfahren zum Eintreiben eines Stahlpfahls nach Anspruch 1 in den Boden durch Rütteln, während gleichzeitig ein Fluid zum Austritt aus dem Fluidsammelund -verteilerkanal (3') entlang dem unteren Rand des Pfahlkörpers gebracht wird, dadurch gekennzeichnet, daß das Fluid veranlaßt wird, ausschließlich im wesentlichen vertikal nach unten auszutreten, und so eingestellt wird, so daß es gerade ausreichend ist, um das Erdreich unmittelbar unter dem unteren Ende des Pfahlkörpers in einen fluidisierten Zustand zu bringen.

3. Verfahren zum Eintreiben eines Stahlpfahls in den Boden durch Rütteln, wobei der Pfahl von dem Typ ist, der einen Pfahlkörper mit einem Fluidaustrittsrohr (3) entlang einem Teil seines untersten Endrands aufweist, wobei die Fluidaustrittsöffnungen (4) des Austrittsrohrs sämtlich im wesentlichen abwärts gerichtet sind, wobei das Verfahren den Schritt aufweist: Austretenlassen eines Fluids durch die im wesentlichen abwärts gerichteten Austrittsöffnungen und Einstellen der Fluidzufuhr so, daß sie gerade ausreichend ist, um das Erdreich unmittelbar unter dem untersten Ende des Pfahlkörpers in einen fluidisierten Zustand zu bringen.

Revendications

1. Pieu en acier, adapté pour être enfoncé dans le sol et ayant le long d'au moins une partie de son bord terminal inférieur un élément formant bord épaissi qui comporte deux parties de bande (6) positionnées de chaque côté d'une partie d'âme du corps de pieu et formant, en association avec ladite partie d'âme, un passage de collecte et de distribution de fluide (3') qui est relié à un conduit d'alimentation en fluide (5') qui s'étend le long du corps de pieu vers le bas, passage à partir duquel du fluide sous pression peut pénétrer dans le sol environnant pendant l'enfoncement du pieu, caractérisé en ce que lesdites deux parties de bande (6) s'étendent vers le bas au-delà de la partie d'âme respective, de manière à former ledit passage sous la forme d'un canal dirigé sensiblement vers le bas situé entre lesdites deux bandes en dessous du bord inférieur de ladite partie d'âme.

2. Procédé pour enfoncer un pieu en acier selon la revendication 1 dans le sol par mise en vibration, tout en provoquant simultanément l'alimentation en fluide à partir du passage de collecte et de distribution de fluide (3') le long du bord inférieur du corps de pieu, caractérisé en ce que le fluide est amené à être alimenté exclusivement sensiblement verticalement vers le bas et est commandé pour être juste suffisant pour amener le sol situé immédiatement en dessous de l'extrémité inférieure du corps de pieu dans un état fluidisé.

3. Procédé pour enfoncer un pieu en acier dans le sol par mise en vibration, dans lequel le pieu est du type comportant un corps de pieu ayant un tube d'alimentaion en fluide (3) le long d'une partie de son bord terminal inférieur et les ouvertures d'alimentation de fluide (4) dudit tube d'alimentation sont toutes dirigées sensiblement vers le bas, le procédé comportant l'étape de provoquer une alimentation en fluide à travers lesdites ouvertures d'alimentation dirigées sensiblement vers le bas et à commander l'alimentation en fluide pour qu'elle soit juste suffisante pour amener le sol situé immédiatement en dessous de l'extrémité terminale inférieure du corps de pieu dans un état fluidisé.

Drawing