Method for forming holes in earth and setting subterranean structures therein

Abstract

A method of forming a hole in earth and of installing a subterranean structure, wherein a rigid open-ended tube is lowered into the earth and simultaneously air under pressure is discharged into the lower end of the tube to displace and discharge soil. The subterranean structure is inserted in the tube at desired position and the tube is withdrawn while the structure remains in position. The apparatus employed to practice the method includes means carried by the tube providing a gas pressure passage with an inlet at one end of the tube and an outlet into the opposite end of the tube, and means by which the tube may be supported at the end adjacent the inlet. The supported end of the tube may mount a shiftable deflector for soil being discharged.

Parent Case Text

CROSS-REFERENCE TO RELATED APPLICATION

This is a Division of my U.S. application Ser. No. 340,238, filed Mar. 12, 1973 and now Pat. No. 3,825,082.

Description

This invention relates to a method and apparatus for forming holes in earth and setting subterranean structures therein, such as well points, submersible pumps and structural members.

In many types of construction work, such as laying sewers, installing building foundations, and building bridges, conditions are encountered which entrail high water content of subsurface soil or sandy soil, or other conditions which render subsurface soil unstable and make the desired construction work difficult. In such cases, it is common to install well points or submersible pumps adjacent to the area in which the work is to be performed to permit withdrawal of water from the soil around the area in which the work is to be performed and thereby stabilize and solidify the soil as required for acceptable working conditions of the construction area. The installation of well points, submersible pumps or other structural elements under subterranean water conditions or sandy or mucky soil conditions is frequently quite difficult and time consuming. Thus, if a drill or other means is used to form a hole to receive the well point or any other subsurface installation, its use may be ineffective because no means exists to maintain a desired hole at a subsurface level at which subsurface water exists or at which loose sand or muck exists and fills the hole with water-laden dirt or sand as the drill or digging tool is removed. Such conditions are encountered frequently so that the installation of a well point or other subterranean unit to the desired depth cannot be accomplished easily or rapidly.

It is the primary object of this invention to provide a method and apparatus which enables a well point or other subterranean structure to be installed at desired location and at desired depth, rapidly and with minimum risk of failure, regardless of the existence of subsurface water, sand, muck, or other conditions which have heretofore been difficult to overcome by prior methods and the use of previously known apparatus.

A further object is to provide a novel, simple and rapid method of forming a hole in earth.

A further object is to provide a method by means of which a rigid open-ended tube is progressively lowered endwise into soil while gas under pressure is discharged into the lowermost end of the tube, as a means to progressively displace and discharge soil upwardly through the tube as the tube descends.

A further object is to provide a method of this character by which a tube is lowered endwise into soil and the soil and its contents penetrated thereby are simultaneously ejected through the tube until a selected depth is reached, whereupon a well point or other subterranean structure is inserted in the tube, following which the tube is withdrawn to leave the well point or other structure in place in the soil.

A further object is to provide a method of this character by means of which a tube is progressively lowered into the soil while simultaneously removing the soil and its content from the tube as it is lowered, followed by insertion into the tube of a well point or other object having a clearance fit within the tube, the filling of the clearance space between the well point and the tube with granular or other packing material, and then withdrawal of the tube while the installed well point and packing material are retained in selected position within the soil.

A further object is to provide apparatus for installing a subterranean structure or unit wherein a rigid open-ended tube is provided with a longitudinal passage which discharges into the lower end of the tube and which communicates at the opposite end of the tube with a source of air under pressure.

A further object is to provide apparatus of this character provided with means at one end of a rigid tube for supporting and manipulating the tube, means for discharging air under pressure into the lowermost end of the tube, and means for guiding or directing the discharge of soil and effluent from the upper end of the tube as the tube is lowered endwise and through soil and subsurface or subterranean materials.

A further object is to provide apparatus including a tube with means at its upper end by which the tube may be elevated and lowered, means at its lower end for discharging therein air under pressure, and means at its upper end for deflecting materials discharged from the tube, which deflecting means are shiftable to afford access for the insertion of articles and materials into the tube through its upper end when installed within the earth.

Other objects will be apparent from the following specification.

In the drawings:

FIG. 1 is a perspective view illustrating apparatus for the practice of the method.

FIG. 2 is a perspective view, with parts broken away, illustrating one embodiment of apparatus used in the practice of the method.

FIG. 3 is a view illustrating the direction of discharge of soil and effluent in the practice of the method by the use of one embodiment of the invention.

FIG. 4 is an enlarged vertical sectional view of the apparatus taken on line 4--4 of FIG. 5.

FIG. 5 is a transverse sectional view taken on line 5--5 of FIG. 4.

FIG. 6 is a transverse sectional view taken on line 6--6 of FIG. 4.

FIG. 7 is a transverse sectional view taken on line 7--7 of FIG. 4.

FIG. 8 is a view illustrating a step in the practice of the method of installing a well point or other subterranean structure.

FIG. 9 is a view illustrating another step in the practice of the method by the use of the apparatus.

FIG. 10 is a view illustrating a well point or other structure installed upon completion of practice of the method.

My new method contemplates the lowering of a rigid open-ended tubular member endwise into the soil while simultaneously discharging into the lower end of the tube air or gas under pressure sufficient to displace and expel soil through the tube as the tube is lowered to provide a hole of selected depth. A well point or other subterranean structure having a clearance fit within the tube is received within the tube, following which the tube is withdrawn while the well point or other structure to be installed remains in place. The method may entail the introduction of filler material between the well point or other unit being installed and the tubular casing prior to or incident to withdrawal of the casing so as to be retained in a subsurface location surrounding the well point or other installed item.

The tubular member is provided at its upper end with inlet means for connection with a source of air or gas under pressure, and a passage discharging gas into the lower end of the tubular member. Means to facilitate and direct lowering and elevation of the tubular member are provided at the upper end thereof. Releasable or shiftable means is selectively positionable to direct the discharge of soil and effluent material from the tube or open the upper end to afford access to the tube for introduction therein of articles to be located in a submerged or subterranean position upon elevating withdrawal of the tube.

One embodiment of the apparatus suitable for utilization in the practice of the method is illustrated herein. Such apparatus, as illustrated in FIG. 1, includes power actuated mechanism 20 adapted to raise and lower an object. The mechanism 20 may be a crane, a backhoe, or the like, which is preferably of mobile character and of sufficient size, strength and utility to serve the required purpose. In the case of a backhoe, a power actuated mechanism supports a rigid, pivoted, elongated arm 22 whose vertical angular position may be selectively varied, a rigid extension arm 24 is pivoted to the upper end of the arm 22 under the control of suitable power actuated mechanism capable of swinging arm 24 to selected vertical angular position on arm 22, and a bucket or shovel 26 pivoted at the free end of the rigid arm 24 and adjustable upon arm 24 by power actuated means as the arm 24 or the arm 22 or both arms 22 and 24 are shifted. The bucket 26, as shown in FIG. 1, or the free movable terminal portion of any other power driven hoist mechanism for raising and lowering articles, is provided with means such as hooks, clamps, jaws, or the like (not shown), at which may be releasably connected one end of an elongated tubular unit 28. The apparatus also utilizes an air compressor 30, preferably portable, connected by a flexible tube 32 to the tubular unit 28 to supply air under pressure to tube 28 adjacent to the supported end of the tubular unit 28.

The construction of the unit 28 may be of the character best illustrated in FIGS. 2, 4, 5, 6 and 7. The construction utilizes an elongated rigid open-ended tube 40, preferably formed of metal, and of selected length and of substantially uniform bore diameter throughout its length. At one end thereof the tube 40 mounts members defining a chamber 42 which preferably encircles the tube. The chamber 42 preferably includes a top wall 44 having an opening therein to receive the end of the tube 40, and is preferably continuously welded at said opening around the circumference of the tube 40. A lower wall 46 spaced below top wall 44 also has a central opening into which the tube 40 fits and around which the tube 40 is welded continuously circumferentially, except at one or more notches 48, as best illustrated in FIGS. 4 and 5 for purposes to be described. The chamber 42 is completed by outer walls 50 which span the space between the plates 44 and 46, and which are sealingly secured to the margins of the plates 44 and 46, as by welding or any other means, so as to provide a chamber 42 which is substantially pressure-tight. The chamber walls 50 may provide a substantially square chamber encircling tube 40, as illustrated in FIG. 5, or may be of any other shape found suitable. The chamber 42 is provided with an inlet fitting 52 of any suitable type adapted for connection with a cooperating outlet fitting 54 carried by the end of air conduit 32 and preferably including a swivel.

One or more passage-defining members are secured to the tube 40 to extend lengthwise thereof from the chamber-defining structure. As here illustrated, these passage-defining members constitute channel member 60 whose legs bear upon and are continuously welded at 62 to the outer surface of the tube 40 and whose upper ends are welded at 64 to the bottom wall 46 around the notches 48. The lower end of the tube 40 is encircled by a rigid, short tube 66 of greater inner diameter than the outer diameter of tube 40. The tubes 66 and 40 are fixedly anchored together in concentric relation by means of spacers 68, as best seen in FIG. 7. The lower end portion 70 of tube 66 projects slightly beyond the adjacent end of the tube 40. Tube 66 is of a length short compared to the length of tube 40 and extends to the lower ends of the channels 60 which are welded thereto at 72 in a manner to provide open communication between the passages provided by the channel members 60 and the clearance space between the tubes 66 and 40. The upper portion of the tube 66 not connected to the channels 70 is closed at 74, as by welding the circumference of the tube 66 to the circumference of the tube 40 continuously between channels 60, in cases where more than one channel 60 is provided. It is preferred that two or more channels 60 be provided and that the same be substantially equi-spaced circumferentially of the tube 40.

At the upper end of the apparatus, as at the upper end of one side wall 50, are provided lugs or ears 80 to which are pivotally connected ears 82 of a deflector. The deflector preferably includes a curved hood or deflector plate 86 having depending side walls 88 adapted in one position, as illustrated in FIGS. 2 and 4, to bear upon the margins of the plate top wall 44 of the chamber 42 in outwardly spaced relation to the tube 40. The deflector plate 86 is spaced above the upper end of tube 40 in its operative position and its free end preferably projects from the chamber-defining structure at the side opposite the pivot 84. The deflector provides clearance space for and directs laterally the discharge of material ejected from the upper end of the tube in the manner illustrated in FIGS. 3 and 4 and at an outlet opening 90.

The upper end structure of the rigid tubular unit 28 is completed by any suitable means which may be engaged by hooks, clamps, jaws or the like carried by the actuating or hoisting mechanism 20. Thus, as here illustrated, a structure may be secured to the chamber unit 42 of a nature to provide spaced lugs or ears 92 projecting from one of the walls 50 and interconnected by a cross bar 94 with which a hook or jaw or clamp is engageable. The cross bar 94 will preferably be positioned laterally of, between and clear of the inlet fitting 52 and the discharge opening 90.

In the practice of the method by the use of the apparatus, the hoisting mechanism 20 and compressor 30 are located adjacent the point at which the well point or other subterranean structure is to be installed. The conduit 32 of the compressor is connected with the inlet fitting 50 of the elongated rigid tubular unit 28, and the hoisting mechanism is connected to the elongated rigid tubular unit at cross bar 94. The hoisting mechanism 20 is then operated to position the elongated rigid tubular unit 28 vertically at the point at which the well point or other member is to be installed. The hoisting mechanism 20 is then operated to lower the tubular elongated unit 28 endwise, while in substantially vertical position, into contact with the ground at the lower end of the tube portion 70 thereof. When such contact of the tube unit 28 with the ground occurs pressure is exerted to force the tube into the ground and the line or conduit 32 from the compressor 30 is opened to supply compressed air to the chamber 42. The pressure will preferably be in the range from 75 psi to 125 psi or more at the compressor or supply outlet. Compressed air flows from line 32 through chamber 42, the channels 60, and the annular chamber between lower tube part 66 and tube 40, and thence inwardly into the tube 40, and discharges upwardly through the open upper end of the tube 40. The flow of compressed air in this path coincident with the lowering of the rigid tubular unit 28 forces the unit 28 into the soil, displaces the soil within the lower end of the unit and discharges the displaced soil upwardly through the tube 40. The displaced material is discharged laterally in selected direction or location determined by the deflector 86 as illustrated in FIGS. 3 and 4. Lowering of the tube continues until it reaches the selected depth in the soil, as at a position as illustrated in FIG. 9. The material discharged will include dirt, sand, water and stones. Thus stones as large as five inches have been discharged in use of the apparatus.

After the tubular unit 28 is installed to desired depth the well point, submersible pump or other subterranean structure 100 to be installed in the subterranean position is lowered into the tube 40, as in the manner partially illustrated in FIG. 8, and as accommodated by pivotal movement of the deflector 86 to a lateral open position, as shown in FIG. 8, which provides clear vertical access to the upper end of the tube 40, as seen in FIG. 8. The well point or other structure 100 may be of any suitable character, and, as here shown, includes the usual screen structure 102 at its lower end and a Tee or other fitting 104 at its upper end. The well point or other unit 100 will be of a cross sectional size for free and clearance fit thereof within the tube 40. The tube 40 may be of any selected diameter, such as diameters ranging from 6 inches to 14 inches or more, and of a selected length, as from 12 feet to 30 feet or more, to accommodate the reception of the unit 100. The unit 100 is lowered into contact with the soil 108 at the lower end of the tube 40, or into contact with filler material, such as sand or gravel 106, which is introduced into the lower part of the tube before the insertion of the unit 100. The desired amount of filler material 106 is then introduced in tube 40 to surround the lower portion of the well point or other subterranean unit 100. After the unit 100 has been placed in selected position the hoisting mechanism 20 is actuated to withdraw the tubular unit 28 vertically. In usual practice, the amount of fill material 106 introduced will not exceed that which can conveniently be shoveled into the upper end of the tube unit 28 by workmen incident to the withdrawal thereof.

As the tubular unit 28 is withdrawn, the soil surrounding the bore which had been formed by and within the tube unit is free to compact around the filler material 106 and around the installed unit 100, thereby holding the installed unit 100 in the desired subterranean position. Upon withdrawal of the tube unit 28, the fitting 104 of the well point or other structure 100 may be connected by conduit means 110 with a water delivery system (not shown), as by connecting a group of well points to means to pump subterranean water from the soil. The withdrawal of water by the installed units 100 serves to solidify the soil at the working area at which construction is to take place.

From the foregoing it will be seen that my improved method entails the formation of a hole in the earth by lowering a rigid open-ended tube into the earth and simultaneously discharging gas under pressure into the lowermost end of the tube to displace soil and discharge soil upwardly through the tube. The method entails the further step of placing a well point or other subterranean structure within the tube at selected subterranean position, the introduction of filler material into the tube around the lower part of the inserted structure, and finally the withdrawal of the tube while leaving the subterranean structure in desired location within the earth.

The method is useful in a wide range of operating conditions and with most subsoil conditions encountered. As subsoil strata of different types are encountered the apparatus permits successful practice of the method in most instances. Even a stratum of clay can be penetrated by alternately raising and lowering the tube until the stratum is broken to form a hole which will receive the tube and the broken pieces of which will pass through and be discharged from the tube by the air under pressure. Only the presence of a rock stratum or contact of the lower end of the tube with subsurface rocks or rigid obstacles of large size will normally prevent successful practice of the method.

While the construction of the apparatus and the steps of the method herein described are preferred, it will be understood that changes may be made within the scope of the appended claims without departing from the spirit of the invention.

Claims

What I claim is:

1. The method of installing a subterranean structure in the earth consisting of the steps of

lowering an open-ended rigid tube endwise into the earth

discharging gas under a pressure of at least 75 psi substantially uniformly around and below the lower end of the tube for flow into the lower end of the tube while lowering the tube to thereby displace soil and discharge displaced soil and gas upwardly through the tube until the tube is lowered to selected depth,

lowering a subterranean structure into the tube at said selected depth, and

withdrawing the tube while said subterranean structure remains at selected depth.

2. The method defined in claim 1, wherein filler material is introduced into said tube around said subterranean structure befor withdrawal of said tube.

3. The method defined in claim 1, wherein a quantity of filler material is introduced into said tube before said subterranean structure is lowered therein and a further quantity of filler material is introduced into said tube around said subterranean structure at its lowered position in said tube before withdrawal of said tube.