GB2158493A

GB2158493A - Method of installing a pile

Info

Publication number: GB2158493A
Application number: GB08506813A
Authority: GB
Inventors: Stuart Komaromy
Original assignee: Earl & Wright Ltd
Current assignee: Earl & Wright Ltd
Priority date: 1984-03-16
Filing date: 1985-03-15
Publication date: 1985-11-13
Also published as: GB8506813D0; GB8406847D0

Abstract

A pile having a grout channel 11 extending along all or part of its length, means to introduce grout into that channel, and a temporary closure member 14 for the channel arranged so that said closure member is opened when grout is introduced into the channel under sufficient pressure, thus permitting grout to flow into the soils around the pile. <IMAGE>

Description

SPECIFICATION Method of installing a pile The invention relates to the installation of a pile.

The invention provides a pile having a grout channel extending along all or partof its length, means to introduce grout into that channel, and a temporary closure memberforthe channel arranged so that said closure member is opened when grout is introduced into the channel under sufficient pressure, thus permitting groutto flow into the soils around the pile.

Preferablythe pile is hollow, and the channel is disposed along the inside surface ofthe pile.

It is preferred that there is a temporary closure memberforthe channel ator near one end of the pile, and adjacentto that closure memberthere is a non return valve, whereby grout cannotflow back into the channel.

It is also preferred thatthere are a plurality of channels extending along the pile.

In this last mentioned form the channels are advantageously symmetrically disposed around the periphery ofthe pile.

The invention also provides a method of installing a pile which comprises the steps of driving the pile to a required depth, and then introducing grout under pressure to soils around that piiethrough a grout channel in the pile and a temporary closure member forthat channel, which closure member is designed to be opened when grout is introduced into the channel under sufficient pressure.

In one form there is a non return valve adjacent to thetemporaryclosure member, and the grout is introduced through a stinger extending along the channel which stinger has an inflatable packer adapted to close this channel, wherein afterthe pile has been driven, the packer is inflated to close the channel, grout is introduced under sufficient pressure to open the closure member and flow into the soils surrounding the pile, grouting pressure is reduced within the channel (the non return valve preventing back flow from the surrounding soil), and the stinger is detached on the side ofthe packer away from the opened closure member, and is then withdrawn.

In anotherform the grout is introduced through a stinger extending along the channel,which stinger has two verticaly spaced inflatable packers adapted to close this channel, wherein afterthe pile has been driven, the packers are inflated to close off a length of the channel, grout is introduced under sufficient pressure to open the closure member and flow into the soil surrounding the pile, grouting pressure is reduced within the channel and the stinger is decoupled above the packers, and is then withdrawn.

Preferablytherearebuiltin non return devices which are operative before the stinger is withdrawn.

A specific embodiment of the invention (and two variants thereof) will now be described by way of example with reference to the accompanying drawings in which: Figure lisa side elevation of a pileforan offshore structure, Figure 2 is a cross section of that pile along the line II - II, Figures 2A and 2B arevariants ofthe cross section shown in Figure 2, Figure 3 is a scrap section of a portion of the pile tip in the region of circle III, Figure 4 is a sketch of a base grouting stinger, Figure 5 is a sketch of a side grouting stinger, and Figures 6to 16 are diagrammatic illustrations of a sequence of events in the installation of a pile.

As shown in Figures 1 and 2 a hollow pile 10 (which is intended for example to form part of the foundation foran offshore oil platform) has four internal grout channels 11 symmetrically arranged on its internal wall surface 12. Each ofthefour grout channels has a series of temporary closure members 14 disposed along its length. The closure members 14 are located in the external wall surface 15 of the pile 10. It will be understood that the temporary closure members 14 exist merely to prevent soil getting into and blocking the channel while the pile is being driven. A non return valve would fulfill the same purpose.

Figures 2A and 2B show alternative cross sectional configurations in which the channels 1 1A and 11 B are formed of pipes extending down the interior of the pile. In figure 2Athe pipes are unshielded, and in Figure 2B they are protected by cover plates.

Atthetip ofthe pile-shown in more detail in Figure 3-the channels 11 terminate at end closure members 16. These closure members 16 are located in the tip surface of the pile. Within the channels 11 and adjacent to the closure members 16, there are non return ball valves 17 arranged to permittheflow of grout from the channel into the soils surrounding the end ofthe pile, but to prevent return flow.

The ball valve 17 at the base may be replaced by an alternative non return device being part of the pile system or part of a grout stinger system detailed hereunder.

Figures 4and 5 show grouting pipes (referred to within the art as stingers) capable of introducing grout down the channels 11. Figure 4 shows a base grouting stinger, designed to introduce grout at the tip of the pile. This stinger has an end aperture 18, a single inflatable packer 19 a short distance above the aperture 18, and a de-couplable 21 a short distance above the packer 19.

Figu re 5 shows a side grouting stinger which has an aperture 25 between a pair of inflatable packers 22 and 23, and a de-couplable connection 24 a short distance abovethe upper packer 23.

Figures 6 to 16 are diagrammatic illustrations of a sequence of events in the installation of a driven and grouted pile.

In figure 6the Pile loins driven into the soil to the required depth or refusal.

In Figure7the basegroutingstinger(shownin Figure 4) is inserted so that it extends down to the base tip of the pile. The packer 19 is inflated in Figure 8, and in Figure 9 grout is injected under pressure so that it bursts open the temporary closure member, and flows out into the soils surrounding the base tip ofthe pile, so to grout up part ofthe base ofthe pile.

In Figure 10 the stinger is uncoupled atthe connection 21 above the non return valve 17 and the packer 19. The base grouting stinger is then withdrawn.

The steps shown in Figures 7,8,9 and 10 are then repeated for the remaining three grout channels, so to complete grouting atthe base ofthe pile.

Figure 11 illustrates the insertion of a side grouting stinger (see Figure 5) so that it is level with the lowest side grouting temporary closure.

The top and bottom packers 23 and 22 of the side grouting stingerare inflated in Figure 12; and in Figure 12A grout is pumped under pressure down the stinger and bursts outthrough the lowest side grouting hole.

As shown in Figure 14the stinger is then uncoupled at 24 (above the non return valve), and is withdrawn.

In Figure 15 the side grouting stinger is inserted to the next highest side grouting hole, and the steps shown in Figures 11 to 14 are repeatedforall four grout channels at each level of grout holes until the pile is fully grouted.

Thefullygrouted pile is represented in Figure 16. It is the intent of the arrangement shown in the specific embodiment that the sequential use of multiple grout outlets will ensure thatthere will be a circumferential zone of groutsurrounding the pile, so to bend this pile to the surrounding soil.

Claims

1. A pile having a grout channel extending along all or part of its length, means to introduce grout into that channel, and a temporary closure memberforthe channel arranged so that said closure member is opened when grout is introduced into the channel undersufficient pressure, thus permitting grout to flow into the soils around the pile.

2. A pile as claimed in claim 1 in which the pile is hollow, and the channel is disposed along the inside surface ofthe pile.

3. A pile as claimed in claim 1 or 2 in which there is a temporary closure memberforthe channel at or near one end ofthe pile, and adjacentto thatclosure member there is a non return valve, whereby grout cannotflow back into the channel.

4. A pile as claimed in any one of the preceding claims in which there are a plurality of channels extending along the pile.

5. A pile as claimed in claim 4 in which the channels are symmetrically disposed around the periphery of the pile.

6. A method of installing a pile which comprises the steps of driving the pile to a required depth, and then introducing grout under pressure to soils around that pile through a grout channel in the pile and a temporary closure memberforthatchannel,which closure member is designed to be opened when grout is introduced into the channel under sufficient pressure.

7. A method as claimed in claim 6 in which there is a non return valve adjacent to the temporary closure member, and t:le grout is introduced through a stinger extending along the channelwhich stinger has an inflatable packer adapted to close this channel, wherein afterthe pile has been driven, the packer is inflated to close the channel, grout is introduced under sufficient pressure to open the closure member and flow into the soils surrounding the pile, grouting pressure is reduced within the channel (the non return valve preventing back flow from the surrounding soil), and the stinger is detached on the side of the packer awayfrom the opened closure member, and is then withdrawn.

8. A method as claimed in claim 6 in which the grout is introduced through a stinger extending along the channel, which stinger has two verticaly spaced inflatable packers adapted to close this channel, wherein after the pile has been driven, the packers are inflated to close off a length of the channel, grout is introduced under sufficient pressure to open the closure member and flow into the soils surrounding the pile, grouting pressure is reduced within the channel and the stinger is decoupled above the packers, and is then withdrawn.

9. A method as claimed in claim 8 in which there are built in non return devices which are operative beforethe stinger is withdrawn.

10. A pile substantially as hereinbefore described with reference to and as shown in Figure 1 to 3 orals modified in Figures 2A or 2B ofthe accompanying drawings.

11. A method substantially as hereinbefore described with reference to the accompanying drawings.