GB2322658A

GB2322658A - Sheet pile seal

Info

Publication number: GB2322658A
Application number: GB9704041A
Authority: GB
Inventors: Jonathan Edward Marshall; David Ernest Thompson; Eric Caldwell
Original assignee: DEW GROUP Ltd
Current assignee: DEW GROUP Ltd
Priority date: 1997-02-27
Filing date: 1997-02-27
Publication date: 1998-09-02
Also published as: GB9704041D0

Abstract

A method and apparatus for producing a seal between the interlocking, open-sided channels (2) along the longitudinal edges (1) of two adjacent sheet piles comprises a first pile, a second pile and a sealant injection conduit (3).The sealant injection conduit (3) is dimensioned so that it can be inserted into and drawn from the channel (2) and is driven into the ground at the same time as the first pile. The bottom end of the channel (2) of the first pile may be plugged to prevent material being forced up into the channel and conduit. Additionally, a cover (5) can be attached to the conduit to prevent the ingress of ground material into the channel. Once in position, the conduit is drawn upwards out of the channel (2). As this proceeds a suitable sealing fluid is pumped downwards through the tube to fill the channel. When the conduit has been removed a second sheet pile can be driven into the ground in an interlocking relationship with the first panel. The injected sealant is displaced and forms a seal between the two.

Description

SHEET PILE T,' SEAL JIJS waL The present invention relates to a method and apparatus for producing a seal between two piles having interlocked longitudinal edges.

The use of interlocked sheet piles driven into the ground so as to produce containing walls is well known. The sheet piles used in such walls have channels along their longitudinal edges which can be interlocked so as to maintain the longitudinal edges of adjacent piles in contact with each other whilst enabling adjacent piles to slide relative to each other. A wall is formed by driving a first sheet pile into the ground, interlocking the bottom end of a channel of a second sheet pile with the top end of a channel of the first sheet pile, driving the second sheet pile into the ground, and then repeating the process to insert third, fourth etc piles into the wall.

The joint defined by the interlocking channels of adjacent piles is adequate for structural purposes, but is not normally watertight. There are certain circumstances in which it would be highly advantageous to form a reliable waterproof seal between adjacent piles.

For example watertight seals are sometimes required to form boundaries around waste disposal sites or to enclose areas of polluted ground.

European patent specification number EP 0628662 describes one known method of producing a seal between adjacent piles. This method involves the use of piles with a conventional channel along one edge and an enlarged channel along the other, adjacent piles being interlocked by interlocking the conventional channel of one pile with the enlarged channel of the adjacent pile, and the enlarged channel of each joint defining a void into which a sealant may be injected. Unfortunately this approach to the problem of sealing adjacent piles requires the manufacture of non-standard piles.

A second approach to addressing the problem of sealing the joint between adjacent piles is described in European patent number EP 0348012. That document describes a system in which an auxiliary section is interlocked with and driven into the ground with each pile.

The auxiliary section incorporates a conventional channel to interlock with the driven pile, that channel supporting a pair of tubes through which sealant may be injected. After a pile and auxiliary section have been driven together into the ground, the auxiliary section is withdrawn leaving a void in the ground surrounding the edge of the pile with which the auxiliary section is initially interlocked. Sealant is pumped through the tubes as the section is withdrawn so as to fill the space left by the withdrawn section. The next pile is then interlocked with and driven into the ground, the interlocked edge of the driven pile being forced through the previously injected sealant. The result is generally an acceptable seal, but if the sealant is to perform the desired function it must flow from the point of injection into the channel of the pile which is being vacated by the withdrawal of the auxiliary section, and there is therefore the risk that ground material will enter the channel defined by the pile, preventing the subsequent formation of the reliable seal.

It is an object of the present invention to obviate or mitigate the problems outlined above.

According to the present invention, there is provided a method for producing a seal between first and second piles longitudinal edges of which define channels that may be interlocked by sliding one pile relative to the other in the longitudinal direction, wherein a sealant injection conduit is interlocked with one edge of the first pile so as to extend along substantially the full length of that edge, the first pile and the injection conduit are driven into the ground together, the injection conduit is withdrawn from the ground, sealant being injected through the conduit as it is withdrawn so as to fill the space adjacent the pile edge vacated by the conduit, a lower end of the second pile is interlocked with the upper end of the first pile, and the second pile is driven into the ground and through the previously injected sealant, characterised in that the injection conduit is received within the channel of the first pile such that injected sealant is delivered directly into the channel as the conduit is withdrawn.

Thus in accordance with the present invention sealant is injected directly into the space where it is required that is into the space defined by the channel in which the conduit was received as the pile was driven in to the ground. The risk of ground material entering the channel and as a result threatening the integrity of the final seal is thus substantially reduced.

Preferably the end of the channel of the first pile which is driven into the ground is plugged to obstruct the entry of ground material into the channel as the pile is driven.

Preferably the conduit is connected to a cover which extends outside and across an open side of the pile channel into which the conduit is inserted, thereby to obstruct the entry of ground material into the channel as the pile is driven.

The invention also provides a pile sealant injection apparatus comprising a sealant injection conduit which is dimensioned to be received within an open sided channel extending along the longitudinal edge of a pile.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 illustrates a first embodiment of the present invention and shows an end view of a channel formed along one edge of a conventional sheet pile into which a tubular sealant injection conduit has been inserted; Figure 2 is perspective view illustrating a second embodiment of the present invention and shows a sealant injection conduit similar to that of Figure 1 but incorporating a further component to prevent ground material entering the channel; Figure 3 is end view of a sheet pile edge channel into which sealant has been injected using a conduit as illustrated in Figure 2; and Figure 4 is an end view of a seal joint between two conventional sheet pile channels formed by driving the channel of a further sheet pile into the sealant-fill channel of Figure 3.

Referring to Figure 1, an edge 1 of a conventional sheet pile defines an open-sided channel 2. The channel 2 extends along the full length of one longitudinally extending side of the sheet pile. The other longitudinal edge of the sheet pile defines a channel which is dimensioned to interengage with the channel shown in Figure 1. Thus as is conventional practice a sheet pile wall can be formed by driving a first pile into the ground, interengaging the upper end of one of the channels defined by the inserted pile with the lower end of the mating channel of the second pile, and then driving the second pile into the ground such that the mating channels become interlocked along their full lengths.

In accordance with the present invention, a joint between two adjacent piles can be formed by driving the first pile into the ground with a sealant injection conduit received within the channel with which a subsequently driven pile is to be interlocked. As shown in Figure 1, the injection conduit can be a simple tube 3 which is dimensioned so that it can be readily inserted into and drawn from the channel and yet is too large to pass through the opening 4 defined by the channel. The bottom end of the channel of the first pile to be driven may be plugged so as to prevent ground material being forced upwards into the channel and the tube 3. After the pile and tube 3 have been driven into the ground, some ground material may have penetrated into the channel 2 around the tube 3 but such penetration will be limited by the presence of the tube 3. The tube 3 is then withdrawn whilst at the same time pumping liquid sealant such as cement grout or bitumen through the tube so as to fill all of the space left by the withdrawn tube. When a second pile is subsequently driven into the ground in an interlocked relationship with the first panel the injected sealant is displaced and forms a reliable seal between the two piles.

In the arrangement described with reference to Figure 1, some ground material may enter the channel 2 as the pile and tube are driven into the ground. The risk of this occurring can be substantially reduced by combining the tube with a cover which extends through and across the open side 4 of the channel. For example, a tube 3 may be welded to a cover defined by a steel angle 5 as shown in Figure 2. The interconnected tube 3 and angle 5 are inserted into a first pile before it is driven into the ground, the pile is then driven into the ground, and the tube 3 and angle 5 are withdrawn as sealant is injected into the channel 2 through the tube 3. As illustrated in Figure 3 the result is that a body of sealant 6 is formed within the channel 2 after withdrawal of the tube. There is substantially no risk of ground material entering the channel 2 and being incorporated in the body of sealant 6.

Figure 4 illustrates an assembled joint between the edge 1 of a first pile and the edge 7 of a second pile. It will be noted that the sealant body as shown in Figure 3 has been displaced as the second pile is driven into the ground so as to form a body of sealant which fills all of the space defined between the interlocked pile edges. As a result a very reliable seal is ensured.

It will be appreciated that conduits having cross-sections which are not circular could be inserted into the channel 2. For example, a conduit could have a cross-section which makes it a relatively close fit in the channel to reduce the risk of ground material entering the channel around the conduit.

Claims

1. A method for producing a seal between first and second piles longitudinal edges of which define channels that may be interlocked by sliding one pile relative to the other in the longitudinal direction, wherein a sealant injection conduit is interlocked with one edge of the first pile so as to extend along substantially the full length of that edge, the first pile and the injection conduit are driven into the ground together, the injection conduit is withdrawn from the ground, sealant being injected through the conduit as it is withdrawn so as to fill the space adjacent the pile edge vacated by the conduit, a lower end of the second pile is interlocked with the upper end of the first pile, and the second pile is driven into the ground and through the previously injected sealant, characterised in that the injection conduit is received within the channel of the first pile such that injected sealant is delivered directly into the channel as the conduit is withdrawn.

2. A method according to claim 1, wherein the end of the channel of the first pile which is driven into the ground is plugged to obstruct the entry of ground material into the channel as the pile is driven.

3. The method according to claim 1 or 2, wherein the conduit is connected to a cover which extends outside and across an open side of the pile channel into which the conduit is inserted to obstruct the entry of ground material into the channel as the pile is driven.

4. A pile sealant injection apparatus comprising a sealant injection conduit which is dimensioned to be received within an open-sided channel extending along the longitudinal edge of a pile.

5. An apparatus according to claim 4, wherein the conduit is connected to a cover which is dimensioned to extend through and across an open-sided channel into which the conduit has been inserted.

6. A method for producing a seal between first and second piles longitudinal edges of which define channels that are interlocked substantially as herein before described with reference to the accompanying drawings.

7. A pile sealant injection apparatus substantially as herein before described with reference to the accompanying drawings.