US3599732A

US3599732A - Method for providing a hole in the soil as well as a device for applying said method

Info

Publication number: US3599732A
Application number: US855528A
Authority: US
Inventors: Jacob Kroon
Original assignee: Tot Aanneming Van Werken Voorheen HJ Nederhorst NV
Current assignee: Tot Aanneming Van Werken Voorheen HJ Nederhorst NV
Priority date: 1968-09-05
Filing date: 1969-09-05
Publication date: 1971-08-17
Anticipated expiration: 1988-08-17
Also published as: GB1245313A; DE1944686B2; DE1944686C3; FR1597317A; DE1944686A1; NL6812692A; NL137084C; BE723204A; MY7300404A

Abstract

A method and a device for providing a hole in the soil, for example for forming a foundation element, an earth-retaining wall or a water-retaining wall or the like in the soil, wherein a hollow pipe open at the lower end is introduced into the soil and the earth penetrated into the pipe is removed from the pipe. According to the invention the removal of the earth from the pipe is effected by a pressure fluid which is supplied to the pipe near the lower end of the pipe, and which forces the earth in the pipe upwards as a column.

Description

United States Patent Inventor Jacob Kroon Gouda, Netherlands Appl. No. 855,528

Filed Sept. 5, 1969 Patented Aug. 17, 1971 Assignee N.V. Tot Aanneming Van Werken Voorheen 11.,1. Nederhorst Gouda, Netherlands Priority Sept. 5. 1968 i Netherlands METHOD FOR PROVIDING A HOLE IN THE SOIL AS WELL AS A DEVICE FOR APPLYING SAID METHOD 20 Claims, 7 Drawing Figs.

US. Cl 175/20, 17 5/60, 175/422 lnt. Cl E21b 11/02, E21b 49/00 Field of Search 175/65, 60, 422, 20, 215

Primary Examiner-James A. Lcppink Attorney-Waters, Roditi, Schwartz and Nissen ABSTRACT: A method and a device for providing a hole in the soil, for example for forming a foundation element, an earth-retaining wall or a water-retaining wall or the like in the soil, wherein a hollow pipe open at the lower end is introduced into the soil and the earth penetrated into the pipe is removed from the pipe.

According to the invention the removal of the earth from the pipe is effected by a pressure fluid which is supplied to the pipe near the lower end of the pipe, and which forces the earth in the pipe upwards as a column.

PATENTEU m1 1 m1 SHEET 1 UF 3 h an 1 :1 l u l SHEET 2 UF 3 PATENTEU AUG] 7 I97! METHOD FOR PROVIDING A HOLE IN THE SOIL AS WELL AS A DEVICE FOR APPLYING SAID METHOD BACKGROUND OF THE INVENTION l This invention relates to a method for providing a hole in the soil, for example for forming a foundation element, an earth-retaining wall or a water-retaining wall or the like in the soil, wherein a hollow pipe open at the lower end is introduced into the soil and the earth, which penetrates into the pipe is removed from the pipe; as well as to a device for applying said method.

According to a known method, after the pipe has been introduced into the soil, the earth which penetrates into the pipe is removed therefrom by mechanical means, for example by means of an auger. However, this is rather time consuming and requires complicated equipment, furthermore the removed earth requires much space on the building site and the removal of this earth from the building site is a messy operation.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for providing a hole in the soil which presents considerable advantages over the above-described known method.

According to the invention the removal of the earth from the pipe is effected by a pressure fluid which is supplied to the pipe near the lower end of the pipe and which forces the earth in the pipe upwards as a column.

Compressed air, pressurized water or other pressurized fluid may be used as a pressure fluid.

According to the invention the removal of the earth from the pipe is effected very rapidly, and the clearing of the earth emerging as a column at the top of the pipe may be carried out for example by deflecting this column laterally and dividing the earth into slices which leave the building site by truck or via a conveyor belt. Consequently the space taken up on the site by the earth to be removed is small and the abovedescribed method results in a clean operation.

It is preferred to reduce the friction between the inner wall of the pipe and the earth in the pipe prior to and/or during the time that said earth is forced upwards. In this way a plug action is prevented at the lower end of the pipe during the introduction of the pipe into the soil and as a result the length of the mass of earth entering the pipe is always almost equal to the depth of penetration ofthe pipe into the soil.

In order to reduce the aforesaid friction, the pipe may have a lower cutting edge the inner cross section of which is slightly less than the inner cross section ofthe pipe. I

By correctly shaping the cutting edge, the advantage may be obtained that the earth, which is displaced by the pipe in consequence of its wall thickness, must deflect outwards and will be in contact with the outer surface of the pipe, which is of great importance since in this way the pressure fluid supplied to the pipe is prevented from flowing out of the pipe via its lower end and escaping upwards around the pipe.

In order to reduce the friction between the inner wall of the pipe and the earth contained in the pipe it is also possible to introduce the pipe into the soil while the pipe is being vibrated and/or to vibrate the pipe during the time that the earth is forced upwards.

Furthermore, this friction may be reduced by supplying a lubricant, such as for example a bentonite suspension, to the pipe near the lower end of the pipe during the introduction of the pipe into the soil, for which purpose the supply conduit for the pressure fluid may be used. In this case, said lubricant can also be utilized as a pressure fluid and therefore, when the pipe has reached the required depth in the soil, it is possible to continue atonce the supply thereof but now under increased pressure.

If it is necessary to form the hole in a highly permeable soil the danger may arise that the pressure of the pressure fluid supplied to the pipe near its lower end penetrates into the earth contained in the pipe, and consequently the lateral pressure of this earth on the interior of the pipe, and therefore the friction between this earth and the interior of the pipe increases so that the forcing upwards of the earth is considerably reduced and may even come to a standstill. In order to prevent this, there may be formed a sealing layer in the lower portion of the pipe, but above the point of supply of the pressure fluid, prior to forcing the earth upwards in the pipe.

This may be done for example by means of chemical injection, as is known per se for soil hardening so that a hard homogenous sealing layer is obtained.

If a liquid under pressure is used as a pressure fluid, sheetlike sealing elements having a specific gravity which is lower than that of the liquid may be added to the liquid, in order to form a sealing layer. These sealing elements will collect and by mutual overlapping will constitute the sealing layer. It is for example possible to add small pieces of synthetic foil, such as polyvinyl chloride foil having a surface area of a few cm. to the liquid under pressure.

A further possibility for forming the sealing layer consists in supplying an emulsion to the pipe near its lower end, the carrier of said emulsion filtering out in the earth and the floating substances of said emulsion constituting the sealing layer.

The invention furthermore comprises a device for providing a hole in the soil by means of the aforedescribed method.

BRIEF DESCRIPTION OF THE DRAWING The invention will be further explained with reference to the drawings, wherein:

FIG. 1 is a vertical section of the lower portion of a first embodiment of the device according to the invention for providing a hole in the soil.

FIG. 2 is a vertical section of the lower portion of a modified embodiment of the device for providing a hole in the soil.

FIG. 3-7 show diagrammatically the various processing steps for forming an earth-retaining wall in adjacent holes in the soil which are successively provided with the device according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS At present holes are provided in the soil for many purposes, for example for soil testing, for drainage or lowering the water level and for forming foundation elements, such as piles or the like, or earth-retaining walls or water-retaining walls in the soil.

FIG. 1 shows a first embodiment of the device according to the invention for providing such holes in the soil. This device comprises a hollow pipe 1, the cross section of which is cylindrical but may have any shape. The pipe 1 comprises near its lower end at least one, but preferably several lateral inlet openings 2 each connected to a supply conduit 3 extending in upward direction immediately outside the pipe 1.

To the lower end of the pipe 1 there is secured, by means of bolts 4, a pipe section 5, the enlarged central portion 5' of which abuts against the inner wall of the pipe 1. The pipe section 5 further comprises a lower portion 5" of reduced thickness, which connects via an exterior upwardly and outwardly slanting collar 6 to the likewise upwardly and outwardly slanting lower edge 6' of the pipe I and which ends at the lower end, via an upwardly and outwardly slanting lower edge 7, into a cutting edge 8, the inner cross section of which is slightly smaller than the inner cross section of the pipe I, The pipe section 5 further comprises an upper end portion 5 of reduced thickness extending in upward direction from a collar 9, which fits against the inner surface of the pipe I and which extends horizontally a small distance below the inlet openings 2.

The upper end portion 5'' defines with the inner surface of the pipe 1 an annular space 10, open at the top, into which the inlet openings 2 end.

Above the inlet openings 2 a distributor ring 11 is secured in said annular space 10, said ring 11 fitting externally of the inner surface of the pipe 1 and internally ofthe upper end portion 5, said ring 11 being provided with a plurality of passages 12 for the pressure fluid distributed along the periphery. In each of these passages 12 a valve 13 has been screwed from the top, said valve being constructed similar to a bicycle tire valve and cooperating with a rubber valve tube 14. These valve tubes 14 end at about the same level as the upper end portion 5" of the pipe section 5.

When introducing the pipe 1 into the soil the cutting edge 8 of the pipe section 5 will ensure that the friction between the earth entering the pipe 1 and the inner wall of the pipe 1 is restricted to a minimum.

Furthermore, when driving the pipe 1 into the soil, a lubricant, such as for instance a bentonite suspension, may be supplied via the supply conduits 3 to the annular space in the pipe 1, said lubricant passing through the valves 13 and bringing about an additional reduction of the friction between the inner wall of the pipe 1 and the earth entering this pipe 1.

After the pipe 1 has been introduced into the soil to a predetermined depth, a pressure fluid-for which purpose compressed air or a liquid under pressure may be used-is supplied via the supply conduits 3 to the lower ends ofthe pipe 1 and the earth contained in the pipe 1 is forced upwards as a column.

At the upper end of the pipe 1, the direction of movement of the rising column of earth may be deflected and the earth may be divided into slices. Further, removal of this earth from the building site may be effected for example, by truck of conveyor belt or similar device.

During tests, a pipe 1 having an inner diameter of 488 mm., which had been provided at the lower end with a cutting edge 8 having an inner diameter of 478 mm. was driven into the earth over a distance of 25 m. in 2 minutes with the aid of a Schenck DR6O vibrator. An ll percent bentonite suspension was thereby supplied as a lubricant via the supply conduits 3 to the pipe 1 and during the introduction of the pipe 1 about 300 liters of said suspension were used.

Immediately after the pipe 1 had been introduced into the soil to the above-mentioned depth, the supply of the bentonite suspension was continued, but now under a higher pressure, and the earth came up as a column out of the pipe 1. During the upward movement of this earth, the supply pressure of the bentonite suspension was gradually reduced thus ensuring a practically contact rate of discharge of the column ofearth.

FIG. 2 shows a modified embodiment of the device according to the invention for providing a hole in the soil. In this embodiment a pipe section 15 having a cutting edge 8 at its lower end is secured to the pipe 1 by means of welding. The lower portion 1 of the pipe 1 has the same inner cross section as the pipe piece 15, said inner cross section being slightly less than the cross section of the upper portion 1 of the pipe I. At the transition between the pipe portions 1' and 1'' an inner collar 16 of the pipe 1 slants inwards and downwards. The inlet openings 2 are provided immediately above this collar 16 in the pipe I.

A support ring 17 is welded in the pipe portion 1 and has an inwardly and upwardly slanting upper edge 18 defining together with the collar 16 a groove of V-shaped cross section. This groove accommodates an end strap 19 of a cable 20 extending upwardly at the outside of the pipe 1 and passed through a pipe 21 which has been mounted on the outer wall of the pipe 1.

After the pipe 1 has been inserted into the soil to the required depth, the upper end of the cable 20 is pulled, whereupon the end strap 19 cuts through the column of earth and forms a bottom surface at the earth in the pipe 1 and the pressure fluid-which subsequently is supplied via the supply conduits 3 to the pipe lmay immediately apply pressure on said bottom surface.

FIGS. 3-7 show diagrammatically the forming of an earthretaining wall in holes provided in the soil in the aforedescribed manner.

In FIG. 3 a round pipe 22 has been brought into the soil by vibration down to the required depth whereupon the earth penetrated in said pipe 22 has been forced upwards by a pressure fluid.

In FIG. 4 a second pipe 23 has been inserted into the soil while being vibrated, said second pipe having a flat substantially rectangular cross section and extending with a narrow side to the pipe 22, and the earth which penetrated into said pipe 23 may be removed in the manner described above.

In FIG. 5 a reinforcement has been arranged in the pipe 22 and concrete has been poured whereupon the pipe 22 has been pulled out and under vibration has been driven again into the soil at the other side of the pipe 23, whereafter the earth which has penetrated into the pipe 22 is removed.

In FIG. 6 a reinforcement has been arranged in the pipe 23 and concrete has been poured, whereafter the pipe 23 has been pulled out and while being vibrated has again been driven into the soil adjacent the pipe 22 but at an angle to its previous position whereupon the earth which has entered the pipe 23 has been removed.

In this way a zigzag-shaped earth-retaining wall (FIG. 7) can be very rapidly formed in the soil. If the pouring of the concrete is carried out at such rate that the mortar of each elongated intermediate portion may merge with the mortar of the adjacent columns, then an excellent waterproof wall is obtained.

The invention is not restricted to the embodiments shown in the drawings which may be varied within the scope of the appended claims.

I claim:

1. A method for forming a hole in the ground comprising vertically introducing a hollow pipe which is open at its lower end from the surface of the earth into the earth to the ultimate depth of the hole, vibrating the pipe during such introduction into the earth, and removing the earth which has penetrated into the pipe only after the pipe has reached its ultimate depth by supplying a pressure fluid into said pipe near its lower end to force the earth in said pipe upwards as a solid mass the introduction of the pipe into the earth being achieved solely by the vibration and in the absence of supply of pressure fluid.

2. A method according to claim 2, comprising reducing the friction between the inner wall of the pipe and the earth contained in the pipe, prior to and/or during the time that said earth is forced upwards.

3. A method according to claim 2, comprising forming the lower end of the pipe with a cutting edge, the inner cross sec tion of which is slightly less than the inner cross section of the pipe.

4. A method according to claim 2, comprising vibrating the pipe during the time that the earth is forced upwards.

5. A method according to claim 2, comprising introducing a lubricant into the lower end of the pipe during the introduction ofthe pipe into the soil.

6. A method according to claim 1 comprising forming a sealing layer in the lower portion of the pipe above the point of supply of the pressure fluid prior to forcing the earth in the pipe upwards.

7. A method according to claim 6, wherein said sealing layer is formed by chemical injection.

8. A method according to claim 6 comprising supplying an emulsion to the pipe near the lower end of said pipe, the floating substances of said emulsion constituting the sealing layer.

9. A method according to claim 1, comprising gradually reducing the supply pressure of the pressure fluid in the period during which the earth is forced upwards.

10. A method according to claim 1, wherein compressed air is used as the pressure fluid.

11. A method according to claim 1, wherein a liquid supplied under pressure is used as the pressure fluid.

12. A method according to claim 11, comprising adding sheetlike sealing elements having a specific gravity lower than that ofthe liquid to said liquid under pressure.

13. A method according to claim 12, wherein said sealing elements are small pieces ofa synthetic foil.

14. A method according to claim 1, wherein an 1 1 percent bentonite suspension supplied under pressure is used as said pressure fluid.

15. A method according to claim 1, wherein the pipe is raised after the earth has been forced upwards out of the pipe.

16. A device for forming a hole in the soil, said device com prising a hollow pipe having an open lower end and at least one lateral inlet opening near said open lower end; a supply conduit means connected to said inlet opening for the supply of a pressure fluid thereto and a pipe section secured to the lower end of said pipe and including a cutting edge, said pipe section having an inner cross section which is slightly less than the inner cross section of said pipe, said pipe section including an upper end portion of reduced thickness extending upwardly in spaced relation from said pipe and defining an annu- 18. A device according to claim 17, comprising a valve extending in the longitudinal direction of the pipe mounted in each of said passages, said valve having an upper end situated at substantially the same level as the top of the upper end portion of reduced thickness.

19. A device for forming a hole in the soil, said device comprisinga hollow pipe having an open lower end and at least one lateral inlet opening near said open lower end, a supply conduit means connected to said inlet opening for the supply of a pressure fluid thereto, a pipe section secured to the lower end of said pipe and including a lower cutting edge, said pipe section having an inner cross section which is slightly less than the inner cross section of said pipe, and a cable'having an end strap supported in the pipe at the level of said inlet opening, said cable extending upwards outside the pipe.

20. A device according to claim 19, wherein said pipe has an upwardly and outwardly slanting collar and comprising a support ring mounted in the pipe and having an inwardly and upwardly slanting upper edge facing said collar, said end strap being supported by said upwardly and outwardly slanting collar of the pipe and said inwardly and upwardly slanting upper edge of the support ring.

Claims

3. A method according to claim 2, comprising forming the lower end of the pipe with a cutting edge, the inner cross section of which is slightly less than the inner cross section of the pipe.

5. A method according to claim 2, comprising introducing a lubricant into the lower end of the pipe during the introduction of the pipe into the soil.

12. A method according to claim 11, comprising adding sheetlike sealing elements having a specific gravity lower than that of the liquid to said liquid under pressure.

13. A method according to claim 12, wherein said sealing elements are small pieces of a synthetic foil.

14. A method according to claim 1, wherein an 11 percent bentonite suspension supplied under pressure is used as said pressure fluid.

16. A device for forming a hole in the soil, said device comprising a hollow pipe having an open lower end and at least one lateral inlet opening near said open lower end; a supply conduit means connected to said inlet opening for the supply of a pressure fluid thereto and a pipe section secured to the lower end of said pipe and including a cutting edge, said pipe section having an inner cross section which is slightly less than the inner cross section of said pipe, said pipe section including an upper end portion of reduced thickness extending upwardly in spaced relation from said pipe and defining an annular space with said hollow pipe which is open at the top of said upper end portion, said pipe section including a collar below the juncture with said upper end portion, said collar being in contact with the hollow pipe and disposed a small distance below said inlet opening.

17. A device according to claim 16 comprising a distributor ring mounted in said annular space above the inlet opening and provided with a plurality of passages for the pressure fluid distributed along the periphery of the ring.

18. A device according to claim 17, comprising a valve extending in the longitudinal direction of the pipe mounted in each of said passages, said valve having an upper end situated at substantially the same level as the top of the upper end portion of reduced thickness.

19. A device for forming a hole in the soil, said device comprising a hollow pipe having an open lower end and at least one lateral inlet opening near said open lower end, a supply conduit means connected to said inlet opening for the supply of a pressure fluid thereto, a pipe section secured to the lower end of said pipe and including a lower cutting edge, said pipe section having an inner cross section which is slightly less than the inner cross section of said pipe, and a cable having an end strap supported in the pipe at the level of said inlet opening, said cable extending upwards outside the pipe.