Method and device for inserting a drainage wick

Abstract

A device for and a method of inserting a drainage wick into the ground comprising the steps of: providing a drainage wick comprising a transversely permeable filter material surrounding a core adapted to longitudinal water circulation, where a portion of said drainage wick is arranged so as to be transversely and/or longitudinally impermeable;threading said drainage wick through an inserting tube;fixing an anchorage component to the lower end of said drainage wick extending out of said inserting tube;driving said anchorage component, said drainage wick and said inserting tube downwardly into the ground; andpulling up said inserting tube whereby said anchorage component and said drainage wick are permitted to remain into said ground.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic perspective view of a device used for implementing an embodiment of a process according to the invention.

FIG. 2 is a diagrammatic view of a drainage wick used to implement the process;

FIG. 3 is a diagrammatic longitudinal section of a portion of apparatus positioned in the ground;

FIGS. 4A and 4B are diagrammatic longitudinal sections of a portion of the equipment according to different process steps of an embodiment of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

An embodiment of a device used to implement one process according to the invention is shown in FIG. 1 and comprises: a frame formed by a hydraulic crane 1; a guide 2; an inserting tube 3; supply means 4 for the drainage wick; a drive member such as cable 6. Guide 2 is arranged in a generally vertical position in operating conditions.

Drainage wick 5 is inserted into the ground by moving the inserting tube 3 in downward direction through the guide 2 using the cable 6 formed in a closed loop fastened at opposite ends to fastening element 9 attached to inserting tube 3. Drainage wick 5 is received in inserting tube 3. Ends of cable 6 are connected to the fastening element 9 and cable 6 fits over reversing wheel 7 arranged on guide 2. The inserting tube 3 is therefore set into movement by rotating wheel 7 to drive the cable 6. Inserting tube may 3 also be moved into the ground by vibration means.

FIG. 2 depicts a drainage wick used to implement a process according to an embodiment of the invention: such a drainage wick 5 comprises a flexible core 52 adapted to longitudinal water circulation. It is usually manufactured of polypropylene. Both sides include grooves, through which water can flow unimpeded. Core 52 is surrounded by a transversely permeable filter material 51. Filter material 51 is made of strong and durable geotextile filter fabric with excellent filtration properties. Free access of ground water is thus permitted into the drainage wick 5. At the same time, this filter prevents agglomeration of fines from adjacent soils and thus avoids clogging.

A typical drainage wick 5 is manufactured in a strip shape, namely in a width of 100 mm and a thickness of about 5 mm. A cylindrical drainage wick comprising cylindrical core is also suitable.

FIG. 3 illustrates an advantageous application of the process. The ground of FIG. 3 consists of two soil layers: layer 41 is a soft soil layer and layer 42 is a hard soil layer, with aquifer presence. Inserting tube 3, anchorage component 11 and the bottom of drainage wick 5 are driven downwardly into the hard soil layer 42, penetrating in the hard soil layer 42. Inserting tube 3 is then pulled up and bottom end of drainage wick 5, fixation point 12 and anchorage component 11 remain in hard soil layer 42. It is thus possible to take advantage of the hard soil layer 42 to fix anchorage component 11 and the soil around anchorage component 11 rearranges or consolidates when pulling up inserting tube 3.

The depth of the upper part of hard soil layer 42 is determined prior to inserting drainage wick 5 into the ground. A portion 20 of drainage wick 5 is determined where water contamination is to be avoided in a corresponding ground zone. In the present example, water contamination of aquifer presence in hard soil layer 42 is to be avoided. Portion 20 is thus determined as starting from the bottom end of drainage wick 5, near fixation point 12 and coming to a point determined to fit a point of soft soil layer 41, close to the upper part of hard soil layer 42, but sufficiently distant of said upper part to avoid water communication between soil layer 41 and soil layer 42. Portion 20 of bottom part of drainage wick 5 is arranged prior to inserting drainage wick 5 into the ground so as to be transversely and/or longitudinally impermeable. It is thus possible to avoid water contamination when hard soil 42 contains an aquifer table and/or to allow processing vacuum soil consolidation.

According to another embodiment or feature of the process disclosed, a hard soil layer is included between two soft soil layers situated one above the other. When such a hard soil layer includes an aquifer and when both soft soil layers have to be drained, one can determine the depth and length of such hard soil layer and, prior to inserting drainage wick into the three stacked soil layers, arrange a portion of the drainage wick so as to be transversely impermeable.

Different steps of an embodiment of the process according to the invention are shown in FIGS. 4A and 4B. FIG. 4A shows the step before inserting the tube 3 into the ground: a drainage wick is unwound from supply means 4, positioned over a wheel 8 and threaded through inserting tube 3. When the lower end of drainage wick 5 is coming out or close to the lower end 15 of inserting tube 3, one can fix an anchorage component 11 to a fixation point 12 of drainage wick 5. The anchorage component 11 shown in FIG. 4A is a disc with a diameter is slightly larger than the maximum size of the external part of the section of inserting tube 3.

The anchorage component 11 is laying on the ground level 40 and the lower end 15 of inserting tube 3 contacts said anchorage component 11. Anchorage component 11 and drainage wick 5 are then driven downwardly into the ground with inserting tube 3. According to an embodiment of the present invention, drainage wick 5 and anchorage component 11 are driven downwardly into the ground by means of inserting tube 3 (see FIG. 4B).

According to another embodiment of the present invention, means are included in the device for inserting the drainage wick so that the distance between wheel 8 and upper part 16 of inserting tube 3 remains constant when driving downwardly inserting tube 3.

When anchorage component 11 and drainage wick 5 have reached their final position, inserting tube 3 is pulled out. After pulling out inserting tube 3, drainage wick 5 is cut near ground level 40 and another drainage wick can be installed.

Referring again to FIG. 4A, a diagrammatic longitudinal section of a portion of the device according to the invention is depicted. The device includes:

• • an inserting tube 3 that is adapted to surround and protect the drainage wick 5 as the inserting tube 3 penetrates downwardly into the earth,
  • a guide such as a mast 2 or pole or shaft, which is designed to initially position the inserting tube 3 generally vertically above the earth,
  • means to move the inserting tube 3 from its initial vertical position downwardly with respect to the guide 2 so that the inserting tube 3 and the drainage wick 5 it protects will penetrate into earth; and
  • means for coating or impregnating the drainage wick 5.

The coating or impregnating means may include a container 24 filled with a water proofing material containing solution 23, elevation means suitable to move up and down container 24, such as an up and down motorized platform 22 supporting said container 24, rolls 25 suitable to drive drainage wick 5 inside container 24 when container 24 is positioned so as to operate coating or impregnation. Coating or impregnation means are not operating as shown on FIG. 4A and are operating as shown on FIG. 4B. Container 24 of FIG. 4A is at its rest position, motorized platform 22 is in a low position and drainage wick 5 remains uncoated or unimpregnated. Alternatively, container 24 of FIG. 4 B has been raised through motorized platform 22 and drainage wick 5 dips in solution 23 to coat the wick 5.

The invention is not restricted to the above described embodiments which can be varied in a number of ways within the scope of the claims.

Claims

1. A method of inserting a drainage wick into the ground comprising the steps of: providing a drainage wick where a portion of said drainage wick is arranged so as to be transversely and/or longitudinally impermeable;threading said drainage wick through an inserting tube;fixing an anchorage component to said drainage wick extending out of said inserting tube;driving said anchorage component, said drainage wick and said inserting tube downwardly into the ground; andpulling up said inserting tube whereby said anchorage component and said drainage wick are permitted to remain into said ground.

2. A method according to claim 1 where the drainage wick comprises a transversely permeable filter material surrounding a core adapted to longitudinal water circulation.

3. A method according to claim 1 where anchorage component and drainage wick are driven downwardly into a first soft soil layer, into a hard soil layer, into a second soft soil layer, said layers being stacked.

4. A method according to claim 1 comprising the steps of: closing the lower end of said inserting tube with a shutter before driving said anchorage component and said drainage wick downwardly into the soilreleasing said shutter before and/or when pulling up said inserting tube.

5. A method according to claim 1 comprising the step of filling the soil zone around the anchorage component with a sealing material before and/or when said inserting tube is pulled up.

6. A method according to claim 1 where said anchorage component and said drainage wick are driven downwardly into a layer of hard soil situated underneath a layer of soft soil and said anchorage component and said drainage wick are permitted to remain in said layer of hard soil.

7. A method of inserting a drainage wick into the ground comprising the steps of: providing a drainage wick where a portion of said drainage wick is impermeably coated or impregnated;threading said drainage wick through an inserting tube;fixing an anchorage component to said drainage wick extending out of said inserting tube;driving said anchorage component, said drainage wick and said inserting tube downwardly into the ground; andpulling up said inserting tube whereby said anchorage component and said drainage wick are permitted to remain into said ground.

8. A method according to claim 7 where drainage wick comprises a transversely permeable filter material surrounding a core adapted to longitudinal water circulation and where a portion of said permeable filter material is impermeably coated or impregnated.

9. A method according to claim 8 comprising the steps of coating or impregnating said portion of said transversely permeable filter material on a beforehand cut length of drainage wick and next threading said drainage wick through the lower end of inserting tube.

10. A method according to claim 8 comprising the step of coating or impregnating said portion of said transversely permeable filter material after unwinding said drainage wick from supply means and before threading said drainage wick through the upper end of inserting tube.

11. A method according to claim 7 where the step of coating or impregnating includes a step of dipping in a water proofing material containing solution and/or projection of a waterproofing material containing solution and/or solid.

12. A method according to claim 11 where said waterproofing material is selected from the group consisting of polymer glue and water activated polymer.

13. A method according to claim 7 where anchorage component and drainage wick are driven downwardly into a first soft soil layer, into a hard soil layer, into a second soft soil layer, said layers being stacked.

14. A method according to claim 7 comprising the steps of: closing the lower end of said inserting tube with a shutter before driving said anchorage component and said drainage wick downwardly into the soilreleasing said shutter before and/or when pulling up said inserting tube.

15. A method according to claim 7 comprising the step of filling the soil zone around the anchorage component with a sealing material before and/or when said inserting tube is pulled up.

16. A method according to claim 7 where said anchorage component and said drainage wick are driven downwardly into a layer of hard soil situated underneath a layer of soft soil and said anchorage component and said drainage wick are permitted to remain in said layer of hard soil.

17. A method of inserting a drainage wick into the ground comprising the steps of: providing a drainage wick comprising a transversely permeable filter material surrounding a core adapted to longitudinal water circulation, where a portion of said core is removed from the lower end of said drainage wick;threading said drainage wick through an inserting tube;fixing an anchorage component to said drainage wick extending out of said inserting tube;driving said anchorage component, said drainage wick and said inserting tube downwardly into the ground;pulling up said inserting tube whereby said anchorage component and said drainage wick are permitted to remain into said ground.

18. A method according to claim 17 comprising the steps of: closing the lower end of said inserting tube with a shutter before driving said anchorage component and said drainage wick downwardly into the soilreleasing said shutter before and/or when pulling up said inserting tube.

19. A method according to claim 17 comprising the step of filling the soil zone around the anchorage component with a sealing material before and/or when said inserting tube is pulled up.

20. A method according to claim 17 where said anchorage component and said drainage wick are driven downwardly into a layer of hard soil situated underneath a layer of soft soil and said anchorage component and said drainage wick are permitted to remain in said layer of hard soil.

21. A device for inserting a drainage wick downwardly into the earth and which includes: an inserting tube that is adapted to surround and protect said drainage wick as the inserting tube penetrates downwardly into the earth,a guide such as a mast, which is designed to initially position said inserting tube vertically above the earth,means to move said inserting tube from its initial vertical position downwardly with respect to said guide so that said inserting tube and the drainage wick it protects will penetrate into earth; andmeans for coating or impregnating the drainage wick.

22. A device according to claim 21 where means for coating or impregnation are dipping means.

23. A device according to claim 22 where dipping means comprise a container filled with a water proofing material containing solution, elevation means suitable to move up and down said container, rolls suitable to drive drainage wick inside said container when said container is positioned in coating or impregnation position.

24. A device according to claim 21 where means for coating or impregnation are pulverization means.