GB2300210A

GB2300210A - Piling

Info

Publication number: GB2300210A
Application number: GB9508233A
Authority: GB
Inventors: Yat Sun Chan
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-04-24
Filing date: 1995-04-24
Publication date: 1996-10-30
Anticipated expiration: 2015-04-24
Also published as: HK1011718A1; GB9508233D0; GB2300210B

Abstract

A piling method includes fitting a steel pile shoe 11 to the bottom of a pile 10. The pile shoe 11 has a cylindrical part 13 completely filled with cementitious material. In use, a hammer is dropped down against the top of the cementations material to drive the pile 10 into the ground. The cementitious material bonds to the inside surface of the pile 10 above the part 13. A second pile may be fixed to the upper end of the first pile 10 by fitting a plate 17, having reinforcing bars 23, inside the first pile adjacent the upper end thereof. A cementitious mixture is poured onto the plate 17 and a plate 18 fitted over the end face. A metal sleeve 24 is fitted around the inside of the lower end of the second pile and the plate 18 is welded to a metal band surrounding the exterior of the lower end of the second pile.

Description

Piling The invention relates to piling.

Piling is commonly used to provide foundations in the ground for buildings and other structures and can require tubular piles to be hammered into the ground.

Pre-stressed concreted tubular piles are generally suitable and better than steel tube piles primarily due to the comparison of costs. However, when a concrete pile is hammered from the top there is a tendency for damage and breakage of the pile to occur especially above ground level. For the pile section already in the ground, lateral compression of the soil generally prevents such damage or breakage. Therefore at present, apart from possible breakage occurring at upper exposed sections of each pile occurring during the piling process, any exposed pile that is cut-off when piling is completed cannot normally be re-used and must be scrapped.

It is an object of the present invention to overcome or at least reduce these problems.

According to one aspect of the invention there is provided a method of piling using tubular piles comprising fitting a pile shoe at the base of a pile having an open topped cylinder which fits inside the base of the pile, completely filling the cylinder with a cementations mixture, and driving the pile into the ground by hammering against the cementations mixture with a hammer which extends down inside the pile from the top of the pile.

The method may include fitting a removable sleeve in the pile which surrounds and allows a head of the hammer to slide up and down inside the sleeve.

The method may include fitting a second pile end to and with the first pile, fitting a one or more plates at the joint between the ends, joining the plates together and filling inside of the joint with cementations material which extends upwards into the second pile to provide a hammering surface for the hammer inside the second pile adjacent its lower end.

The joining method may include fitting a cylindrical sleeve inside and adjacent the lower end of the second pile within which most of the cementations material is contained.

A metallic loop may be fitted with the outside surface of the second tube adjacent its lower end.

According to another aspect of the invention there is provided piling apparatus which comprises a metallic pile shoe having a pointed end and a hollow cylindrical top arranged to fit inside one end of a hollow cylindrical pile which is totally filled with cementations material.

Piling apparatus and a method of piling according to the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows a side view of a pile with a pile shoe fitted to its lower end; Figure 2 shows a cross-sectional view of Figure 1; Figure 3 shows a side view of the pile shoe; Figure 4 shows an isometric view of a hammer for driving the pile into the ground; Figure 5 shows a side view of the ends parts of two piles that are to be joined together end to end; Figure 6 shows a cross-sectional view of the end parts after being joined together; Figure 7 shows an exploded view of an end part of an upper pile prepared to be joined to another pile; Figure 8 shows a pile with a shoe fitted and a hammer inside the pile; Figure 9 is a sectional view of Figure 8;; Figure 10 shows a pile with a shoe fitted with a different hammer near the top of the pile; and Figure 11 is a sectional view of Figure 10.

Referring to the drawings, in Figures 1 and 2 a cylindrical hollow pile 10 is formed of pre-stressed concrete and is provided with a steel pile shoe 11 (also shown in Figure 3) at its lower end. The pile 10 is reinforced by steel bars (not shown) which run in conventional fashion longitudinally down the length of the pile inside its walls. The shoe 11 is formed of a solid pointed body which has an upper open cylinder part 13 extending up inside the pile 10 adjacent its lower end. The cylinder 13 is filled with a cementations mixture. A removable metal sleeve 14 fits inside the pile 10.

In Figure 4. the hammer comprises I-beam shank 15 and a solid cylindrical head 16. The head is formed to be a loose sliding fit in the pile 10 see Figures 8 and 9. In use, the hammer is driven by a diesel engine, or preferably used as a free fall hammer to drive the pile into the ground, in which case the sleeve 14 is included and the hammer is a loose sliding fit in the sleeve, see Figures 10 and 11. The head 16 impacts the cementations mixture. Initial hammering compresses the mixture and some bonding is formed between the mixture and the inside walls of the pile around the top of the cylinder part 13. As a result, the pile shoe 11 receives its impacts through the mixture and via the side bonding. Such impacts therefore do not normally allow or rely on direct metal to metal contact between the hammer head 16 and the shoe 11.Further, the cylinder part 13 prevents hoop stresses in the bottom of the pile which could damage the pile at least during its initial entry into the ground. The sleeve 14 protects the inside surfaces of the pile 10 along its length being damaged by the movement of a free fall hammer up and down inside the pile 10. Importantly, the driving impact is delivered directly during piling to adjacent the lower end of the pile (as compared to normal hammering which is applied at the upper end of the pile) and such that the pile 10 is not likely to be damaged or broken. This means in addition that if all the pile is not driven into the ground1 its exposed upper part can be cut-off and used to form another pile or part of another pile.

The preferred cementat ions mixture consists by weight of one part cement, two parts sand and three parts stone. Water is added to comprise not more than 20% by weight of the cement.

When a first pile has been driven into the ground a second pile is fixed to the upper end of the first pile. The sleeve 14, if present, is removed and a metal plate 17 (see Figures 5 and 6) is fitted at the upper end of the first pile 10. The plate 17 fits inside adjacent the end and then cementations mixture added before a plate 18 is fitted over an upper end face. A metal band 19, as shown in Figure 5 (or a larger band 20 as shown in Figure 7 which is welded to reinforcing steel bars 21) is provided at the lower end of a second pile 22. Inside the pile steel reinforcing bars 23 extend from the plate 17 through the plate 18 up inside the pile 22. A metal cylindrical sleeve 24 is fitted around the inside of the pile 22 surrounding and extending a short distance above the bars 23. The joint between the two piles is held together by externally welding the plate 18 to the band 20. The joint is further filled inside with cementat ions mixture as shown in Figure 6.

When the joint has been completed the sleeve 14 is fitted inside the pile 22 and piling is continued by impacting the head 16 against the top of the cementations mixture inside the joint. As before, impact forces from the head 16 are transmitted to the joined piles by bonding which is formed between the cementations mixture and the inside walls of the pile 22. The walls are protected against any excessive hoop stresses in the vicinity of the joint by the sleeve 24.

Piling is continued until a third (or fourth and so on) pile is required which is joined to the second pile in the same way as described above.

Typically, the pile 10 has a diameter of 66cm and is lOm long. The shoe 11 has a 450 pointed end and its cylindrical part extends about 50cm up into the lower end of the pile 10. The sleeve 24 is also 50cm in height and 0.5cm in thickness. Normally the cylindrical part of the shoe 11 and the sleeve 24 are completely filled with cementations mixture.

Claims

1. A method of piling using tubular piles comprising fitting a pile shoe at the base of a pile having an open topped cylinder which fits inside the base of the pile, completely filling the cylinder with a cementations mixture, and driving the pile into the ground by hammering against the cementations mixture with a hammer which extends down inside the pile from the top of the pile.

2. A method according to claim 1 including fitting a removable sleeve in the pile which surrounds and allows a head of the hammer to slide up and down inside the sleeve.

3. A method according to claim 1 or 2. including fitting a second pile end to and with the first pile, fitting a one or more plates at the joint between the ends, and joining the plates together, and filling inside of the joint with cementations material which extends upwards into the second pile to provide a hammering surface for the hammer inside the second pile adjacent its lower end.

4. A method according to claim 3, including fitting a cylindrical sleeve inside and adjacent the lower end of the second pile within which at least most of the cementations material is contained.

5. A method according to claim 3 or 4, including fitting at the joint a metallic loop flush with the outside surface of the second tube adjacent its lower end.

6. Piling apparatus comprising a metallic pile shoe having a pointed end and a hollow cylindrical top arranged to fit inside one end of a hollow cylindrical pile which is totally filled with cementations material.

7. Piling apparatus according to claim 6, including an elongate hollow pile formed of pre-stressed concrete.

8. A method of piling substantially as herein described with reference to the accompanying drawings.

9. A pile shoe and piling apparatus subtantially as d5 herein described with with reference to the companying drawings.

9. A pile shoe and piling apparatus substantially as herein described with reference to the accompanying drawings.

Amendments to the claims have been filed as follows CLAIMS 1. A method of piling using tubular piles comprising fitting a pile shoe at the base of a pile having an open topped cylinder which fits inside the base of the pile, completely filling the cylinder of the pile shoe with a cementations mixture and driving the pile into the ground by hammering against the cementations mixture with a hammer which extends down inside the pile from the top of the pile.

3. A method according to claim 1 or 2. including fitting a second pile end to and with the first pile.

fitting a one or more plates at the joint between the ends and joining the plates together. and filling inside of the joint with cementat ions material zilch extends upwards into the second pile t provide a hainme r 1 ng surface for the hanirn r I fl I de the Second pile adjacent its lower end.

4. A method accordlng to claim '. i nclu lno fltting a cylindrical sleexe inside and adjacent the lower end eE the second p i IL withing wihch at least most of the cementat ions material is contained.

5. A method according to claim 3 or t. including fitting at the joint a metallic loop flush with the outside surface of the second tube adjacent its lower end.

6. Piling apparatus comprising a metal C pile shoe having a pointed end and a hollow cvl indrical top arranged to fit inside one end of a hol low cylindrical pile which hollow cylindrical top is totally filled with cementat ions material.

Piling apparatus according to claim 6. including an elongate hollow pile formed of pre-stressed concrete.

S. A method of piling substantially as herein described with reference to the accompanying drawings.