WO2015114219A1

WO2015114219A1 - Pile shoe and pile

Info

Publication number: WO2015114219A1
Application number: PCT/FI2015/050062
Authority: WO
Inventors: Vesa Järvinen; Janne VEKKELI; Teemu YLI-KOVERO; Teemu JÄRVINEN; Jukka Rantala
Original assignee: Rautaruukki Oyj
Priority date: 2014-01-31
Filing date: 2015-01-30
Publication date: 2015-08-06
Also published as: EP3102740A1; EP3102740B1; NO3102740T3; FI20145108L

Abstract

The invention relates to a rock shoe and a pile. The pile (2) comprises a first end (3) provided with the rock shoe (1) and a second end. The rock shoe (1) comprises a base plate (10) having a lower surface (14) faced away from the pile (2) and a hole (20) extending from the lower surface (14) towards the pile (2), and a dowel (30) having a neck portion (40) and a drive portion (32). The neck portion (40) is mounted into the hole (20) such that the drive portion (32) protrudes from the lower surface (14) and from the first end (3) of the pile (2). The hole (14) comprises a tapered hole portion (26) tapering from the lower surface (14) towards the pile (2), and the neck portion (40) comprises a tapered neck portion (43) tapering from drive portion (32) and corresponding the tapered hole portion (26).

Description

PILE SHOE AND PILE

FIELD OF THE INVENTION

The present invention relates to a rock shoe according to the preamble of claim 1 and more particularly to a rock shoe for a longitudinal pile to be installed into ground, the rock shoe comprising a dowel comprising neck portion and a drive portion, and a base plate to be mounted to an end of the pile, the base plate comprising a lower surface provided with a hole extending into the base plate, the hole provided to the base plate being arranged to receive the neck portion of the dowel for securing the dowel to the base plate such that the drive portion of the dowel protrudes from the lower surface of the base plate. The present invention further relates to pile according to the preamble of claim 8 and more particularly to a steel pile to be installed into ground, the pile comprising a first end and a second end, the first end of the pile being provided with a rock shoe for penetration into the ground, the rock shoe comprising base plate mounted to the first end of the pile, the base plate having a lower surface faced away from the pile and a hole extending from the lower surface towards the pile, and a dowel having a neck portion and a drive portion, the neck portion of the dowel being mounted into the hole of the base plate such that the drive portion of the dowel protrudes from the lower surface of the base plate and from the first end of the pile.

BACKGROUND OF THE INVENTION

Piles, particularly steel piles and tubular driven steel piles may be provided with a rock shoe facilitating and enabling the penetration of the pile into the ground and a rock shoe also spread the support force of a rock to the whole cross section of a pile. The rock shoe is mounted to the lower end of the longitudinal pile and it is thus the tip of the pile when it is installed into the ground. The rock shoe conventionally comprises base plate mounted to the lower end of the pile and a dowel or point mounted to the base plate. During the installation of the pile into the ground the forces are transferred from the dowel to the base plate and from the base plate further to the pile. The dowel is loosely secured to the base plate and such that the forces are transferred to the base plate linearly in the longitudinal direction of the pile. The base plate is on the other hand mounted to the lower end of the pile such that the forces from the dowel are further transferred to the pile via the lower end of the pile and in the longitudinal direction of the pile. The dowel of the rock shoe may encounter inclined rock surfaces or other hard inclined surfaces in the ground during installation of the pile. In this situation the forces subjected to the dowel are not in the direction of the longitudinal axis of the pile, but the inclined rock surface tends to turn the dowel in relation to the base plate and the pile. This is caused because only one edge portion or corner of the dowel is first pressed against the inclined rock surface. Thus the dowel causes a moment force to the base plate and the loosely to the base plate mounted dowel tends to tilt in relation to the base plate. Accordingly the forces are not transferred from the dowel to the base plate and from the base plate further to the pile in the longitudinal of the pile. The shifted force direction and the tilting of the dowel cause increased loads to the rock shoe, dowel and base plate and also to the pile and subjects the rock shoe and pile to damages and difficulties in the installation of the pile. In the prior art the mentioned disadvantages are tired to be solved by providing very massive and thick base plates which could withstand the increased loads caused by inclined rock surfaces. However, this leads to vary massive constructions in the rock shoes and furthermore it does not solve the problems relating the damaging of the dowel and difficulties in the installation of the pile due to the tilted position of the dowel. BRIEF DESCRIPTION OF THE INVENTION

An object of the present invention is therefore to provide a rock shoe and pile so as to overcome or at least alleviate the prior art disadvantages. The objects of the invention are achieved by a rock shoe according to the characterizing portion of claim 1 , and more particularly with a rock shoe in which the hole of the base plate comprises a tapered hole portion extending and tapering from the lower surface of the base plate into the base plate, and that the neck portion of the dowel comprises a tapered neck portion extending and tapering from drive portion and corresponding the tapered hole portion. The objects of the present invention are further achieved with pile according to the character- izing portion of claim 8, and more particularly with a pile in which a the hole of the base plate of a rock shoe comprises a tapered hole portion extending and tapering from the lower surface of the base plate towards the pile, and a the neck portion of the dowel comprises a tapered neck portion extending and tapering from drive portion and corresponding the tapered hole portion.

The invention is based on the idea of providing a rock shoe which comprises a tapered or conical support surfaces between the dowel of the rock shoe and the base plate of the rock shoe. The base plate is provided with a hole extending from the lower surface of the base plate into the base plate. The hole of the base plate is provided with a tapered or conical hole portion extending and tapering from the lower surface of the base plate into the base plate. The tapered hole portion comprises a tapered hole support surface. The dowel of the rock on the other hand comprises a drive portion which is in contact with the ground and penetrates the ground during installation of the pile, and a neck portion extending from the drive portion are arranged to be mount- ed into the hole of the base plate for securing the dowel to the base plate. The neck portion of the dowel comprises a tapered or conical neck portion extending the drive portion and tapering away from the drive portion. The tapered neck portion comprises a tapered neck support surface. The tapered neck portion and the tapered hole portion correspond each other such that the tapered neck support surface and the tapered hole support surface fit and are arranged against each other during installing the pile. Accordingly the dowel is supported to the base plate via the tapered or conical portion of the hole of the base plate and the neck of the dowel for transferring the forces via the mating tapered hole support surface and the tapered neck support surface.

Accordingly the forces subjected to the dowel during installing the pile are transported from the dowel to the base plate via the tapered or conical support surfaces of the hole of the base plate and neck portion. Therefore, the forces are transported from the dowel to the base plate in the longitudinal direction of the pile and also transversely, or perpendicularly, to the longitudinal direction of the pile. Thus the forces are distributed from the dowel to the base plate and further to the pile effectively and moment forces due to the inclined rock surfaces may be substantially eliminated. The conical or tapered portions and surfaces of the hole and the neck further center the dowel to the hole and prevent the dowel from tilting due to inclined rock surfaces during installation of the pile. Therefore, the rock shoe and the pile may be more effective and accurately installed to a desired location and position in the ground. Furthermore, the base plate may be formed smaller, thinner and not so massive without risk for damages. The rock shoe and pile becomes simpler and material savings may be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS In the following the invention will be described in greater detail by means of preferred embodiments with reference to the attached [accompanying] drawings, in which

Figure 1 shows one embodiment of a base plate in an end of a pile according to the present invention;

Figure 2 shows one embodiment of a dowel of the a rock shoe according to the present invention;

Figure 3 shows features of the base plate and dowel of figures 1 and 2 in more detail;

Figure 4 one embodiment of rock shoe according to the present invention mounted to a pile; and

Figure 5 shows another embodiment of rock shoe according to the present invention mounted to a pile.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 is shows a pile 2 and a base plate 10 of a rock shoe. The pile 2 is preferably a tubular steel pile having an inner surface 6 and an outer surface 4. The pile 2 may further or alternatively be tubular driven pile or the like. The pile 2 comprises lower end 3 having a lower end surface 8. As shown in figure 1 , the base plate 10 of the rock shoe is mounted to the lower end 3 of the pile 2. The base plate 10 is mounted to the first end 3 of the pile 2 with a friction joint such that the base plate 10 is at least partly inside the pile 2 and fitted against the inner surface 6 of the pile 2. The base plate 10 is supported against the lower end surface 8 of the first end 3 of the pile 2 for transferring forces from the base plate 10 to the pile 2. The base plate 10 comprises a first shoulder 16 having a first shoulder support surface 18. The first shoulder support surface 18 is arranged against the lower end surface 8 of the first end 3 of the pile for supporting the base plate 10 to the pile 2 and transferring forces from the base plate 10 to the pile 2. In an alternative embodiment (not shown) the base plate 10 comprises an outer sleeve which is arranged to be fitted against the outer surface 4 of the pile 2 for mounting the base plate 10 with a friction joint to the first end 3 of the pile 2. It is obvious that all parts may also be jointed together by welding. In this embodiment an upper surface of the base plate 10 may be supported to the lower end surface 8 of the first end 3 of the pile 2 for transferring forces from the base plate 10 to the pile 2. The pile 2 and the base plate 10 have preferably circular cross section. The base plate 10 of the rock shoe to be mounted to an end 3 of the pile 2 comprises a lower surface 14 faced away from the pile 2 and an upper surface 12 faced towards to the pile 2. The base plate 10 further comprises a hole 20 extending into the base plate 10 and from the lower surface 14 to- wards the pile 2. In the embodiment of figure 1 the hole 20 is a through hole extending from the lower surface 14 of the base plate to the upper surface 12 of the base plate 12. In an alternative embodiment the hole 20 of the base plate 10 may be a blind hole having depth less than the thickness of the base late 10 and extending from the lower surface 14 of the base plate 10 into the base plate 10. The hole 20 has preferably a circular cross section.

As shown in figure 1 , the hole 14 of the base plate 10 comprises a tapered hole portion 26 extending and tapering from the lower surface 14 of the base plate 10 into the base plate 10. The cross section of the tapered or conical hole portion 26 decreases from the lower surface 14 towards the upper surface 12 and the pile 2. The tapered hole portion 26 comprises a tapered or conical hole support surface 28. The hole 20 of the base plate 10 further comprises a straight hole portion 22 having a uniform cross section and extending from the tapered hole portion 26 into the base plate 10 and to the upper surface 12 of the base plate 10. The straight hole portion 22 comprises a straight hole support surface 24.

Figure 2 shows an embodiment of a dowel 30 of the rock shoe to be mounted to the base plate 10. The dowel 30 comprises a drive portion 32 and a neck portion 40. The drive portion 32 forms the tip or point of the rock shoe for penetration into the ground and the neck portion 40 is provided for mount- ing the dowel 30 to the base plate 10. The dowel 30 has preferable a circular cross section, and drive portion 32 has larger cross section area or diameter that the neck portion 40. Therefore, the dowel 30 may comprise a second shoulder 34 forming a second shoulder support surface 36. The neck portion 40 extends from the drive portion 32, and more particularly from the second shoulder support surface 36 of the drive portion 30. The neck portion 40 of the dowel 30 is arranged to be inserted into the hole 20 of the base plate 10 for mounting and securing the dowel 30 to the base plate 10.

The neck portion 40 comprises a tapered neck portion 43 extending and tapering from drive portion 32 and towards an upper end 42 of the neck portion 40 and dowel 30. The tapered or conical neck portion 43 comprises a tapered neck support surface 46. The tapered neck portion 43 and the tapered neck support surface 46 correspond the tapered hole portion 26 and the tapered hole support surface 28. The neck portion 40 of the dowel 30 comprises a straight neck portion 41 having uniform cross section and extending from the tapered neck portion 43 away from the drive portion 32 and to the upper end 42 of the dowel 30. The straight neck portion 41 comprises a straight neck support surface 44.

Figure 3 shows the tapered hole portion 26 of the hole 20 base plate 10 and the tapered neck portion 43 of the dowel 30 in detail. The depth D of the tapered hole portion 26 into the base plate 10 may be 20 to 100 % or preferably at least 30 % of the thickness A of the base plate 10. Accordingly the tapered hole portion 26 may extend along the hole 20 from the lower surface 14 of the base plate 10 to the upper surface 12 of the base plate 12 or from the lower surface 14 to a bottom of the hole 20 if it is a blind hole. Thus the hole 20 be provided with a tapering cross along the whole depth D, and thus the hole 20 comprises no straight hole portion 22. In the embodiment of figure 3 the depth D of the tapered hole portion 26 is approximately third, or 33 %, of the thickness A of the base plate 10. The tapered hole portion 26 comprises a first tapering angle, or coning angle, a, as shown in figure 3. The first tapering angle a of the tapered hole portion 26 of the base plate 10 may be between 10 to 45 degrees or preferably at least 15 degrees and not more than 35 degrees. The height H of the tapered neck portion 43 of the dowel 30 corresponds preferably the depth D of the tapered hole portion 26. The height H of the tapered neck portion 43 may be maximally the height B of the whole neck portion 40 such that the tapered neck portion 40 comprises no straight neck portion 41 . The tapered neck portion 43 comprises a second tapering angle, or coning angle, β, as shown in figure 3. The second tapering angle β of the tapered hole portion 43 of the neck 40 of the dowel 30 may be between 10 to 45 degrees or at least 15 degrees and not more than 35 degrees. The first and second tapering angle α, β preferably correspond each other and thus the first tapering angle a of the tapered hole portion 26 of the base plate 10 and the second tapering angle β of the tapered neck portion 43 of the dowel 30 may both be between 10 to 45 degrees, or at least 15 degrees and not more than 35 degrees.

Figure 4 shows one embodiment of the rock shoe 1 and the pile of the present invention. The base plate 10 is mounted to the first end 3 of the pile 2. The hole 20 provided to the base plate 10 is arranged to receive the neck portion 40 of the dowel 30 for securing the dowel 30 to the base plate 10 such that the drive portion 32 of the dowel 30 protrudes from the lower surface 14 of the base plate 10. The hole 20 of the base plate 10 comprises the tapered hole portion 26 extending and tapering from the lower surface 14 of the base plate 10 into the base plate 10. The neck portion 40 of the dowel 30 comprises the tapered neck portion 43 extending and tapering from drive portion 32 and corresponding the tapered hole portion 26. As the neck portion 40 is mounted into the hole 20 such that the drive portion 32 protrudes from the lower surface 14 of the base plate 10 and from the first end 3 of the pile 2, the tapered neck support surface 46 is arranged and supported against the tapered hole support surface 28, as shown in figure 4. Furthermore, the second shoulder support surface 36 is arranged and supported against the lower surface 14 of the base plate 10. The tapered hole portion 26 and the tapered neck portion 43 are designed and dimensioned such that tapered support surfaces 28, 46 and the second shoulder surface 36 and the lower surface 14 base plate 10 are arranged against each other at the same time such that the dowel 30 is supported to the base plate 10 by the second shoulder 34 and the tapered neck portion 43. In an alternative embodiment the dowel 30 is supported to the base plate 10 only by the tapered neck portion 43. Thus the second shoulder 34 and the second shoulder surface 36 are not supported against the lower surface 14 of the base plate 10, but there is a gap between the second shoulder surface 36 and the lower surface 14 of the base plate 10. In a yet alternative embodiment the dowel 30 may be formed such that it does not comprise second shoulder 34 at all and thus the dowel 30 is supported base plate 10 only by the tapered neck and the tapered support surfaces 28, 46. It should be noted that in all the embodiments of the present invention the dowel 10 is supported to the base plate 10 at least by the tapered neck portion 43.

As shown in figure 4, the hole 20 of the base plate 10 is a through hole extending from the lower surface 14 of the base plate 10 to an upper sur- face 12 of the base plate 10. Such a hole enables the fixing if a dowel 30 to the base plate 10 with less work. The neck portion 40 of the dowel 30 is arranged to extend in the hole 20 through the base plate 10 from the lower surface 14 to and/or above the upper surface 12, and over the upper surface 14 of the base plate 10. The rock shoe 1 further comprises securing means above the upper surface 12 for loosely securing the dowel 30 to the base plate 10. The securing means may comprise retainer 50, such a s retainer ring or locking ring, ar- ranged to the upper end 42 or vicinity thereof of the neck potion 40 of the dowel 30 for securing the dowel 30 to the base plate 10. As shown in figure 4, the dowel 30 is thus secured loosely between the upper surface 12 and lower surface 14 of the base plate 10. Loosely secured means in this connection that the dowel 30 may move little in the longitudinal direction of the pile 2 relative to the base plate 10. Accordingly the distance between the retainer 50 and the second shoulder 34 is greater than the thickness A of the base plate 10.

Figure 5 shows an alternative embodiment, in which the hole 20 of the base plate 10 is a blind hole having depth D less than the thickness A of the base late 10 from the lower surface 14 to an upper surface 12 of the base plate 10. In this embodiment the upper end of the neck portion 40 remains inside the base plate 10. The securing means comprise retainer 50 arranged to the upper end 42 or vicinity thereof of the neck potion 40 of the dowel 30 and a retainer cavity 52 formed inside the base plate 10. A retainer cavity needs ad- ditional work which is possible to avoid with embodiment according to Figure 4. The neck portion 40 of the dowel 30 is arranged to extend from the lower surface 14 of the base plate 10 to the retainer cavity 52 in the hole 20 for securing the dowel 30 between the retainer cavity 52 and the lower surface 14 of the base plate 10 by means of the tapering neck portion 43 and the retainer 50. Also in this embodiment the invention the dowel 10 is supported to the base plate 10 at least by the tapered neck portion 43 during use.

In the present invention a tapered hole portion 26 in a hole 20 of base plate 10 of a rock shoe 1 and a tapered neck portion 43 in a neck portion 40 of dowel 30 of a rock shoe 1 are used for arranging and supporting the dowel 30 to the base plate 10 such that the neck portion 40 of the dowel 30 is installed into the hole 20 of the base plate 10.

It will be obvious to a person skilled in the art that, as the technology advances, the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.

Claims

1. A rock shoe (1) for a longitudinal pile (2) to be installed into ground, the rock shoe (1) comprising:

- a dowel (30) comprising neck portion (40) and a drive portion (32); and

- a base plate (10) to be mounted to an end (3) of the pile (2), the base plate (10) comprising a lower surface (14) provided with a hole (20) extending into the base plate (10),

the hole (20) provided to the base plate (10) is arranged to receive the neck portion (40) of the dowel (30) for securing the dowel (30) to the base plate (10) such that the drive portion (32) of the dowel (30) protrudes from the lower surface (14) of the base plate (10),

characterized in that the hole (20) of the base plate (10) comprises a tapered hole portion (26) extending and tapering from the lower surface (14) of the base plate (10) into the base plate (10), and that the neck portion (40) of the dowel (30) comprises a tapered neck portion (43) extending and tapering from drive portion (32) and corresponding the tapered hole portion (26).

2. A rock shoe (1) according to claim 1, characterized in that the depth (D) of the tapered hole portion (26) into the base plate (10) is:

- 20 to 100 % of the thickness (A) of the base plate (10); or

- preferably at least 30 % of the thickness (A) of the base plate (10).

3. A rock shoe (1 ) according to claim 1 or 2, characterized in that a first tapering angle (a) of the tapered hole portion (26) of the base plate (10) and a second tapering angle (β) of the tapered neck portion (43) of the dowel (30) is:

- between 10 to 45 degrees; or

- preferably at least 15 degrees and not more than 35 degrees.

4. A rock shoe (1) according to any one of claims 1 to 3, c h a r - acterized in that the hole (20) of the base plate (10) comprises a straight hole portion (22) having a uniform cross section and extending from the tapered hole portion (26) into the base plate (10), and that the neck portion (40) of the dowel (30) comprises a straight neck portion (41) having uniform cross section and extending from the tapered neck portion (43) away from the drive portion (32).

5. A rock shoe (1 ) according to any one of claims 1 to 4, c h a r a c - t e r i z e d in that the neck portion (40) is arranged to extend in the hole (20) through the base plate (10) from the lower surface (14) above the upper surface (12).

6. A rock shoe (1) according to any one of claims 1 to 5, c h a r - acterized in that the rock shoe (1) comprises securing means (50, 52) above the upper surface (12) for loosely securing the dowel (30) to the base plate (10).

7. A rock shoe (1) according to any one of claims 1 to 6, c h a r - acterized in that the drive portion (32) of the dowel (30) comprises shoulder (34) arranged to be supported against the lower surface (14) of the base plate (10) when the dowel (30) is pressed against the base late (10) during use.

8. A steel pile (2) to be installed into ground, the pile (2) comprising a first end (3) and a second end, the first end (3) of the pile (2) being provided with a rock shoe (1) for penetration into the ground, the rock shoe (1) comprising:

- base plate (10) mounted to the first end (3) of the pile (2), the base plate (10) having a lower surface (14) faced away from the pile (2) and a hole (20) extending from the lower surface (14) towards the pile (2); and

- a dowel (30) having a neck portion (40) and a drive portion (32); the neck portion (40) of the dowel (30) being mounted into the hole

(20) of the base plate (10) such that the drive portion (32) of the dowel (30) protrudes from the lower surface (14) of the base plate (10) and from the first end (3) of the pile (2),

characterized in that the hole (14) of the base plate (10) comprises a tapered hole portion (26) extending and tapering from the lower surface (14) of the base plate (10) towards the pile (2), and that the neck portion (40) of the dowel (30) comprises a tapered neck portion (43) extending and tapering from drive portion (32) and corresponding the tapered hole portion (26).

9. A pile (2) according to claim 8, characterized in that the pile (2) is tubular pile having an inner surface (6) and an outer surface (4), or that the pile (2) is a tubular driven pile having an inner surface (6) and an outer surface (4).

10. A pile (2) according to claim 8 or 9, characterized in that the base plate (10) is mounted to the first end (3) of the pile (2) with a friction joint such that the base plate (10) is supported against an end surface (8) of the first end (3) of the pile (2).

1 1 . A pile (2) according to any one of claims 8 to 10, c h a r a c - t e r i z e d in that the neck portion (40) of the dowel (30) extends in the hole

(20) through the base plate (10) from the lower surface (14) to the upper surface (12), and that the dowel (30) is loosely secured to the base plate (10) with securing means (50, 52).

12. Use of a tapered hole portion (26) in a hole (20) of base plate (10) of a rock shoe (1 ) and a tapered neck portion (43) in a neck portion (40) of dowel (30) of a rock shoe (1 ) for arranging and supporting the dowel (30) to the base plate (10) such that the neck portion (40) of the dowel (30) is installed into the hole (20) of the base plate (10).