METHOD AND APPARATUS FOR FORMING STRUCTURES IN THE GROUND

• US 3,638,433 A
• Filed: 03/28/1969
• Issued: 02/01/1972
• Est. Priority Date: 03/28/1969
• Status: Expired due to Term

• Current Assignee: James L. Sherard
• Original Assignee: James L. Sherard
• Inventors: Sherard, James L.
• Primary Examiner(s): Shapiro, Jacob
• Application Number:
  US04/812,574
• Time in Patent Office: 1,040 Days
• Field of Search: 61/11,13,35,36,53.52,53.6,53.64,53.66,63,53.5
• US Class Current: 405/50
• CPC Class Codes: E02D 1/04 Sampling of soil E02D1/025 takes precedence
• CPC Class Codes: E02D 3/106 by forming sand drains containing only loose aggregates sand piles E02D3/08
• CPC Class Codes: E02D 5/30 made of concrete or reinforced concrete or made of steel and concrete E02D5/50 takes precedence; assembled from segments E02D5/523; prestressed concrete E02D5/58
• CPC Class Codes: E02D 5/385 with removal of the outer mould-pipes documents also covered by one or several of the groups E02D5/40 - E02D5/44 are classified in all the relevant groups
• CPC Class Codes: E02D 5/46 making in situ by forcing bonding agents into gravel fillings or the soil consolidating soil in general E02D3/12
• CPC Class Codes: E02D 5/54 Piles with prefabricated supports or anchoring parts; Anchoring piles E02D5/44 takes precedence; ground anchors E02D5/80; anchored foundations E02D27/50
• CPC Class Codes: E02D 5/72 Pile shoes

Abstract

A method for making an elongated liquid-filled hole extending downwardly in the ground which may be used in the construction of foundation piling, water wells, sand drains, tension anchors and related installations, the method comprising generally the steps of providing a rigid, elongated drive member or mandrel having a drive foot on its lower end; forcing the mandrel drive foot through and displacing the soil to form a space with a crosssectional area greater than the mandrel stem in the wake of the drive foot; and simultaneously filling this space with a preselected liquid supplied at the ground surface, the liquid thereby flowing downwardly with the mandrel behind its drive foot. For some embodiments of the invention, the liquid is left in the hole formed where it becomes part of the body of the completed structure, such as in cast-in-place concrete piles or sand drains. The drive foot of the mandrel in all cases is left within the hole and in some instances the mandrel stem is detachable from the drive foot and is removed from the hole formed, either before or after additional liquid is applied, depending on the type of structure being built.

Claims

1. A method of forming a sand drain in the ground comprising the steps:

providing a mandrel having a straight stem and a detachable drive foot at or near its lower end, said drive foot having a cross-sectional area in the direction transverse to the mandrel axis which is larger than the transverse cross-sectional area of the solid portion of the mandrel stem;

moving said mandrel stem downwardly to cause said drive foot to penetrate into the ground so that an elongated hole is formed, the area of which hole is larger than the cross-sectional body area of the mandrel, thus creating longitudinal space in the ground adjacent the mandrel stem behind said downward penetrating drive foot;

causing a liquid to flow downwardly from the ground surface into said longitudinal space simultaneously with the downward mandrel penetration so that at least a portion of this space is immediately filled with liquid as soon as it is created, said liquid serving to prevent the soil or ground water from the walls of the hole from entering said space;

withdrawing said mandrel from the ground while simultaneously causing an additional supply of liquid to flow into the hole in such a way that the volume of the mandrel being withdrawn is replaced with liquid, leaving the detachable drive foot fixed in the ground at the bottom of the liquid-filled hole;

filling said liquid-filled hole with sand by pouring it in from the surface.

2. A method of forming a sand drain in the ground comprising the steps:

providing a mandrel having a straight stem with a hollow interior and a detachable drive foot at or near its lower end, said drive foot having a central opening and cross-sectional area in the direction transverse to the mandrel axis which is larger than the transverse cross-sectional area of the solid portion of the mandrel stem;

moving said mandrel stem downwardly to cause said drive foot to penetrate into the ground so that an elongated hole is formed, having an area larger than the cross-sectional body area of the mandrel, thus creating longitudinal space in the ground adjacent the mandrel stem behind said downward penetrating drive foot, and so that some of the soil lying in the path of the downward penetrating mandrel enters the interior of said mandrel stem in the form of a soil plug, said soil plug inside said mandrel being carried out of the hole along with said mandrel stem;

causing said longitudinal space to be filled with liquid simultaneously with the downward mandrel penetration so that at least a portion of this space is immediately filled with liquid as soon as it is created, said liquid serving to prevent the soil or ground water from the walls of the hole from entering said space;

withdrawing said mandrel from the ground while simultaneously causing an additional supply of liquid to flow into the hole in such a way that the volume of the mandrel being withdrawn is replaced with liquid leaving the detachable drive foot fixed in the ground at the bottom of the liquid-filled hole;

filling said liquid-filled hole with sand by pouring it in from the surface.

3. The method as described in claim 2 including the further step of removing said soil which enters the hollow interior of said mandrel progressively as the mandrel enters the ground.

4. The method as described in claim 3 in which said soil plug is removed from the interior of said mandrel by blowing it out with compressed air.

5. The method as described in claim 2 wherein said mandrel stem is a hollow tubular member having holes spaced apart along its length and said drive foot is an annulus with a central opening, said soil plug having an outside diameter smaller than the inside diameter of the mandrel stem, said water flowing through the holes in the walls of said mandrel stem filling the annular space created between the soil plug and the interior of said mandrel stem during its downward travel.

6. A method of forming a sand drain in the ground comprising the steps:

providing a mandrel with a straight hollow tubular stem and a detachable drive foot at or near its lower end, the exterior dimensions of said drive foot in the direction transverse to the mandrel axis being larger than the exterior diameter of the mandrel stem, said detachable drive foot also having a central opening;

moving said mandrel stem downwardly to cause said drive foot to penetrate into the ground so that an elongated hole is formed with a cross-sectional shape the same as the exterior shape of said drive foot and larger than said mandrel stem, thus creating longitudinal space in the ground adjacent the exterior surface of said mandrel stem behind said downward penetrating drive foot, some of the soil lying in the path of the downward penetrating mandrel entering the interior of the mandrel stem through said drive foot central opening in the form of a soil plug;

causing said longitudinal space that is exterior of said mandrel stem to be filled with liquid simultaneously with downward mandrel penetration, said liquid serving to prevent soil or ground water from the walls of the hole from entering said space, said liquid being a flowable mixture of sand and self-disintegrating mud;

withdrawing said mandrel stem from the ground, said soil plug inside the mandrel being carried out of the ground with the mandrel stem, while simultaneously causing an additional supply of the same liquid to flow into the hole in such a way that the voLume of the mandrel and soil plug being withdrawn is replaced with the liquid, leaving the detachable drive foot fixed in the ground at the bottom of the liquid-filled hole.

7. The method of claim 6 including the further step of moving said soil which enters the hollow interior of said mandrel stem progressively as the mandrel penetrates the ground.

8. The method as described in claim 7 in which said soil is removed from said mandrel interior by blowing it out with compressed air.

9. The method as described in claim 6 wherein said mandrel stem has holes spaced apart along its length and said soil plug has a diameter smaller than the inside diameter of the mandrel stem, said liquid flowing through said holes in the walls of the mandrel stem filling the annular space created between the soil plug and the interior of the mandrel stem during the downward penetration of the mandrel into the ground.

10. The method as described in claim 6 in which said soil plug is left behind in the ground when the mandrel is withdrawn, said sand drain being formed with a tubular shape.

11. A method of forming a sand drain in the ground comprising the steps:

providing a mandrel having a straight stem and a detachable drive foot at or near its lower end, said drive foot having a cross-sectional area in the direction transverse to the mandrel axis which is larger than the transverse cross-sectional area of the solid portion of the mandrel stem;

attaching one end of a porous conduit to said drive foot, said porous conduit having a length approximately equal to that of the sand drain being formed;

moving said mandrel stem downwardly to cause said drive foot to penetrate into the ground so that an elongated hole is formed, the area of which hole is larger than the cross-sectional body area of the mandrel, thus creating longitudinal space in the ground adjacent the mandrel stem behind said downward penetrating drive foot and carrying said porous conduit into the ground inside said elongated hole;

causing liquid to flow into said space simultaneously with downward mandrel penetration so that at least a portion of the space is immediately filled with liquid as soon as it is created, said liquid serving to prevent soil or ground water from the walls of the hole from entering said space, said liquid being a flowable mixture of sand and self-disintegrating mud;

withdrawing said mandrel stem from the ground while simultaneously causing an additional supply of the same liquid to flow into the hole in such a way that the volume of the mandrel being withdrawn is replaced with the liquid, leaving the detachable drive foot fixed in the ground at the bottom of the liquid-filled hole and leaving said porous conduit centrally located in the liquid-filled hole extending at least to the ground surface.

12. A method of creating a sand-filled cavity below ground comprising the steps:

providing a mandrel having a straight stem and a detachable drive foot at or near its lower end, said drive foot having a cross-sectional area in the direction transverse to the mandrel axis which is larger than the transverse cross-sectional area of the solid portion of the mandrel stem;

moving said mandrel stem downwardly to cause said drive foot to penetrate into the ground so that an elongated cavity is formed, the area of which is larger than the cross-sectional body area of the mandrel, thus creating longitudinal space in the ground adjacent the mandrel stem behind said downward penetrating drive foot;

simultaneously filling said cavity with a fluid mixture of sand a viscous liquid, which fluid mixture has sufficient pressure to prevent collapse of the cavity, said viscous liquid having the characteristic that its viscosity decreases with time and gradually approaches the viscosity of water, said mixture within said cavity being left in place while the viscosity of said liquid decreases, thereby eventually leaving the cavity filled only with sand and a liquid having a viscosiTy essentially that of water.

13. The method of claim 12 in which said viscous liquid is a self-disintegrating mud comprising:

a mixture of water and an organic substance with some form of bacteria or enzymes which cause the organic substance to self-destruct within a few days.

14. The method as described in claim 13 including the extra step of placing a porous tubing having a smaller diameter than the diameter of said cavity and positioning it centrally inside said cavity.