US3807184A

US3807184A - Method and means for producing pile or like structural columns in situ

Info

Publication number: US3807184A
Application number: US00287929A
Authority: US
Inventors: L Turzillo
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-03-16
Filing date: 1972-09-11
Publication date: 1974-04-30
Anticipated expiration: 1991-04-30

Abstract

Pile or like structural column produced in earth situs by drilling with continuous flight auger to define cavity of requisite depth, withdrawing auger by successive incremental extents and maintaining auger affixed against axial movement at top of each said extent while feeding and compacting columnforming material, through hollow shaft of auger, into each respective cavity extent, until series of successively formed extents produce integrated column. Closure on inner end of hollow auger shaft operable to stop flow of material at any depth of cavity. For forming concrete pile, closure means operable to form enlarged base or bulb of self-hardening material at bottom of cavity to increase load-bearing capacity of the formed pile.

Description

Turzillo Apr. 30, 1974 METHOD AND MEANS FOR PRODUCING PILE OR LIKE STRUCTURAL COLUMNS IN SITU Inventor: Lee A. Turzillo, 2078 Glengary Rd.,

Akron, Ohio 44313 Filed: Sept. 11, 1972 Appl. No.: 287,929

Related US. Application Data Division of Ser. No. 19,906, March 16, 1970.

US. Cl 61/53.6, 61/5364, 61/63 Int. Cl E02d 5/34, E02d 5/44 Field of Search 61/5352, 53.62, 53.6,

3,422,629 1/1969 Watts 61/5352 Primary Examiner.lacob Shapiro [5 7] ABSTRACT Pile or like structural column produced in earth situs by drilling with continuous flight auger to define cavity of requisite depth, withdrawing auger by successive incremental extents and maintaining auger affixed against axial movement at top of each said extent while feeding and compacting column-forming material, through hollow-shaft of auger, into each respective cavity extent, until series of successively formed extents produce integrated column. Closure on inner end of hollow auger shaft operable to stop flow of material at any depth of cavity. For forming concrete pile, closure means operable to form enlarged base or bulb of self-hardening material at bottom of cavity to increase load-bearing capacity of the formed pile.

3 Claims, 10 Drawing Figures PA'TGNTEUAPR so 1914 SHEET 2 [IF 5 Z a r 5 If I PATENTEUamo 1914 3.807384 SHEEI 3 BF 5 METHOD AND MEANS FOR PRODUCING PILE OR LIKE STRUCTURAL COLUMNS IN SITU This is a divisional application of US. application Ser. No. 19,906, filed Mar. 16, 1970.

BACKGROUND OF THE INVENTION tain best results. With particular reference to production of concrete piles, the present method obviates the I prior art problem of feeding more material into the drilled cavity than necessary for particular purposes, such as where excavation below the existing ground level is specified to be accomplished after the pile installation is completed. The improved method also obviates the prior art problem of spillage of excess fluid cement mortar, or other filler material, above ground adjacent completed structural columns.

SUMMARY OF THE INVENTION The method and means of the invention is for providing a concrete pile or other structural column in an earth situs, and includes rotating a relatively large hollow-shafted auger to form a bore of selective full depth in the situs, with a smaller auger selectively rotatable and axially shiftably mounted in shaft of the larger auger and withdrawing the augers from the formed bore by a plurality of increments of total depth thereof. Upon withdrawal of the augers to define a first hollowbore increment, the smaller auger is selectively axially shifted to project into the bore increment to open a closure carried on the smaller auger, and thereby to open the end of the hollow shaft. The smaller auger is then rotated for forcible mechanical conveyance of fluid bore-filling material through the hollow shaft, of the larger auger until material becomes packed in a first closed hollow bore increment, as by pressure applied by the screw action of the smaller auger. This material compacting procedure is repeated in each successive closed, hollow-bore increment, until a full structural column is formed. The small auger may be selectively withdrawn to close the inner end of the large auger shaft, to stop inward movement of material at any desired depth of bore, such as a predetermined excavation level below the. existing earth surface, to avoid wasting material. Projection of the rotating smaller auger into the bore increments assures maintenance of a uniform mixture of a fluid concrete mix therein, for

example.

Neat cement or mortar may be initially pumped through the smaller auger shaft, before the closure or bit is moved to open the inner end of the larger auger shaft prior to initial withdrawal of the same, thereby to form a concrete base or bulb in the earth at the bottom of the drilled bore, for increasing the point-bearing load capacity of the finishedconcrete pile supported thereon (see FIG. 1).

As an additional feature of the invention, a remote controlled earth cutting blade is provided at the lower end of the large auger to effect, upon rotation of the auger, radial extension of the auger flighting and thereby enlarge the diameter of the drilled cavity, at the bottom thereof. This enlargement is filled with self-hardenable cementitious material, which'upon hardening, forms a base or bulb on which the ultimately formed pile is supported to have substantially increased point-bearing load capacity.

Other objects of the invention will be manifest from the following brief description and the accompanying drawings.

Of the accompanying drawings:

FIG. 1 is a vertical cross-section, partly broken away, through a completed concrete 'pile produced in an earth situs by one embodiment of the improved method of the invention.

FIG. 2 is a vertical cross-section, on the same scale and partly broken away, illustrating the general type of equipment referred to herein, including an auger within an auger, and suitable for practicing the improved methods hereof, at a point in which a pile cavity has beenbores to full depth.

FIG. 3 is an enlarged verticalcross-section, corre-' sponding to the lowerportion of FIG. 2,'but illustrating a first stage of incremental withdrawal of the larger auger, at which fluid cementitious material is about to be forced into the first of a plurality of hollow incremental cavity extents.

FIG. 4 is aview corresponding to FIG. 3, illustrating a subsequent operation of force feeding fluid, selfhardening cementitious material through the large auger shaft into the first said cavity event.

FIG. 5 is a view corresponding to FIG. 4, illustrating completion of the first said concrete pile increment,

and initial movement of the auger within an auger, toward a second incremental stop position for filling a second incremental cavity extent.

FIG. 6 is a fragmentary cross-section corresponding to FIG. 5, but showing the larger auger withdrawn from the cavity to a point above the completed pile, and the smaller auger retracted within the larger auger to close the inner end of the hollow shaft thereof,'to obviate leaving excess concrete above an excavation line or level.

FIG. 7 is a fragmentary cross-section corresponding to FIG 2, on a reduced scale illustrating use of a similar auger within an auger combination, as for forcefully feeding material into a bore made by the larger auger, such as for producing a sand drain in the situs.

FIG. 8 is a fragmentary view corresponding to the lower portion of FIG. 6, but with the smaller auger withdrawn to closed position of a closure thereon.

FIG. 9 is an enlarged-scale viewof the lower portion of the apparatus shown in FIG. 7, but illustrating use of a power-adjustable blade extension on the large auger flighting, for forming a:cavity enlargement as a matrix for a concrete base or hell to increase the point-bearing load capacity of a concrete pile formed by the method of the invention.

FIG. 10 is a horizontal cross-section, taken on the line 10-10 of FIG. 9, and on the same scale.

Referring particularly to FIG. 2 of the drawings,

there is illustrated apparatus 10 for practicing the method of the invention to produce a unitary concrete pile 11 in an earth situs, as shown in FIG. 1. Such appa,

ratus may include a sectional, continuous flight flight, auger 12 rotatably mounted on a'suitable carriage 13,

which is verticallymovable, by means of a hoist cable 14, on guide rails of a drilling rig R. A reversing-type hydraulic motor 16 on the carriage 13 is selectively operable as for rotating the auger 12 about a vertical axis thereof, through a connecting chain drive 17. The

auger 12 is thereby vertically operable at will, to drill a bore or cavity 18 of any predetermined depth, and likewise to withdraw the auger.

For feeding column-forming material, such as hydraulic cement mortar 19, into the bore from a hopper 28, the hollow shaft 20 may have a smaller hollowripheral seat portion 23 normally held in abutment withthe lower end of the larger auger shaft 20, to prevent passage of materials into or out of the shaft passage 24. The smaller auger21, however, is selectively vertically reciprocable, between extended and retracted'conditions with respect to said lower end of the larger auger shaft 20, to open and close the lower end of passage 24 therethrough, as by means of simultaneously operable

hydraulic cylinders

25, 25 mounted on the carriage 13 and selectively operable to reciprocate a support 26 for a hydraulic motor 27, which rotatably carries the smaller auger 21.

Motors

16 and 27 may be synchronized to rotate as one in clockwise direction, during the operation of large auger 12 for drilling the bore 18. When the bore has been drilled to requisite depth, however, as shown in FIG. 2, joint rotation of the two augers l2 and 21 may be stopped, and the

hydraulic cylinders

25, 25 are selectively operable to ram the smaller auger 21 downwardly with respect to the larger auger 12, thereby to open the lower end of shaft passage 24, as shown in FIGS. 3 to 5. While the larger auger 12 may be withdrawn from the formed earth bore 18, by means of hoist cable14 with the cored earth retained in the auger flighting as shown in FIGS. 2 to 9, it is adapted to be stopped and held affixed at any point while the hydraulic motor 27 is selectively operated to rotate the smaller auger in counter-clockwise direction, uniformly and continuously to feed concrete, sand, or other porous materials from a hopper 28 affixed on carriage 13 (see FIG. 2), downwardly through the auger shaft passage 24, and out through the open lower end of the same, with resultant uniform spreading and force-feeding of the material into the closed cavity increment l8i, defined by the selective location of the fixedly spaced inner end of the auger 12.

For the purposes described, the closure or bit 22 may be fishtail shaped to have

curvate portions

29, 29 which dig into the soil during the bore-drilling operation. In the reverse rotational operation of the bit 22 with the small auger, however, said curvate portions conversely will tend to pack the filler material downwardly by holding the larger auger temporarily affixed for a relatively short period. While the smaller auger is rotated as described, the fluid mortar can be fed or conveyed mechanically, by the flighting of the smaller auger, into the closed cavity increment 18i until a suitable back pressure is built up against the cavity walls, which will cause relatively slight upward movement of the larger auger, which is visibly manifested by corresponding slight movement at the upper end of the large auger.

Referring generally to FIGS. 1 to 6, the steps of the improved method represented therein, include first drilling a bore 18 in the earth formation E, as by means of the continuous flight, hollow-shafted auger 12, to predetermined full depth as shown in FIG. 2. Next, the auger 12 is withdrawn from the formed bore 18 by means described above, by successive incremental stages, to a succession of stop positions of auger 12, defining a plurality of cavity increment extents, from each of which the earth of. the situs is removed upwardly by the large'auger flighting and the inner end of the fixed auger 12 is presented toward the respective hollow cavity increment or extent 18i. Starting with the first incremental stage, the large auger 12 is withdrawn from the bore ,18, a given first incremental extent to a momentarily stoppedposition, as shown in FIG. 3, while the smaller auger may be retained inwardly extended from the end of the larger auger as shown in FIG. 3, or at least sufficiently to maintain the closure 22 in open position for downward, pressure-fed movement of the fluid hydraulic cement mortar, or the like selfhardening cementitio us'material, from supply hopper 28, first to fill the first cavity increment with the mortar Y and then to compact the same against the resistance of the enclosing walls of the cavity including portions of the auger flighting and augered earth retained in the flighting. For this purpose, the end of the small auger may be retained, either extended or withdrawn with respect to the larger auger shaft, while said larger auger is being withdrawn to the next incremental stop position, as shown in FIG. 5, which corresponds to FIG. 4 except that the first pile increment lli will have been compactly formed as described above, sided 'by delayed, fluid-agitating retention of a substantial flighted extent of the small auger in the fluid mortar (see chaindotted lines in FIG. 5). This incremental augerwithdrawal and cavity-filling procedure is repeated until a unitary pile 11 of selective extent is formed, as shown in FIGS. 1 and 6, wherein the top of the formed pile is at a below-surface point which subsequently, by excavating, will terminate at the desired elevation. This cut-off procedure is accomplished withoutwaste of cementfmortar because the small auger is easily operable from above ground to move the closure 22 to the closed position thereof, as shown in FIG. 6, to stop the flow of fluid material precisely at any desired elevation, after which bothaugers can be removed from cavity 18 along with the core of augered earth material remaining inthe large auger flighting. Upon setting and hardening of the cement mortar in the successively formed incremental column extents lli, the samewill have been amalgamated into an integral pile body of substantially uniform density (see FIG. 1).

For certain types of less densified soils of the situs, the load carrying capacity of the finished pile may be increased by, at cavity-forming method stage shown in FIG. 2, pumping chemical or cement grout through the small auger shaft 21, to permeate the soil ofthe situs and form a so-called bulb or base 11b, which, upon setting and hardening, provides improved point-bearing support for the subsequently completed pile body 11 (see FIG. 1). v

FIGS. 7 and 8 illustrate a modified form of auger equipment 10a, suitable for practicing methods of the invention to produce piles or columns of any fluid or flowable material, including self-hardenable cementitious material such as cement mortar, or porous mate-- rial such as sand. v

For producing a sand or porous drain column in an earth situs E, for example, the augering equipment of FIGS. 7 and 8 may-include a relatively large, sectional continuous flight auger releasably affixed by means of a coupling 36, to an adaptor tube 37, rotatably mounted on a carriage 38 which is, by a hoist cable 39, vertically movable along guide rails 40 of drilling rig 41. A reversible hydraulic motor 42, on carriage 38, is selectively operable through adaptor 37 to rotate the auger 35 about a vertical axis of the same for drilling a large diameter bore 46 or requisite extent in the situs E, in accordance with methods to be described later. Cutting teeth 47 or other driving means may be provided on the lower end of auger 35.

A hopper 48 may be affixed on lower part 49a of a two-part carriage 49, to be vertically movable therewith along the upright guide rails 40, by means of a hoist cable 50, either concurrently with or independently of the carriage 38. For this purpose, the hopper 48 converges to a tubular section 51 having nonrotatable, quickly releasable connection to the carriage 38 to communicate the interior'of the hopper with the cylindrical passage 52 through adaptor tube 37, to the passageway 53 of the large auger 35 without interfering withrotation of the auger. To this end, the hopper section 51 may have affixed to its lower end a centrally apertured annulus 54, held complementally and nonrotatably seated in peripheral seat means 55 on carriage 38, as by a plurality of quick-acting, springpressed latches 56, 56, provided on a fixed part of the carriage 38.

A reversible hydraulic motor 58 mounted on upper part 49b of the two-part carriage 49, releasably attached to part 49a thereof, carries a relatively small, sectional auger device 59 adapted to extend through the hollow shaft 57 of the large auger 35, selectively to be rotated at the same time or independently thereof, in any rotational direction. For ease of changing the lengths of both augers at the same time, the small auger device 59 may have a releasable coupling of known type, slightly below the coupling 36 of the large auger. In this way, the small auger selectively may be made to extend'either beyond the inner end of the large auger as shown in FIG. 7, or to position a combined driving bit and closure member '61, affixed on the hollow shaft portion 59d of the small auger, within the passageway 53 of the larger hollow shaft 57. Auger device 59 may be reciprocated toward and from the FIG. 6, closed position of closure 61, by releasing latch means 56 and thereby, through cable 50, to raise or lower the carriage 49 with hopper 58 thereon. This actuation 48 carriage 49 also may be utilized to empty hopper 48, or to inspect soil of the situs collected in the flighting of the small auger. Alternatively, the auger device 59 may be similarly reciprocated or retracted, without hopper 48, by releasing upper carriage part 49b from carriage part 49a at 490.

For certain purposes, fluid hydraulic cement mortar or grout, under pressure, may be pumped through the hollow shaft of small auger 59, through a suitable swivel connector 64 at the upper end thereof.

Referring further to FIG. 7, while the small auger de-' vice 59 may be of the substantially continuous-flight type, the present invention contemplates provision of substantial extents 59a and 59b of spiral flighting at the upper and lower ends of small auger shaft 59d, and a substantial intermediate extent 590 of the smaller auger adapted to be contained within the larger auger shaft 57 (see FIGS. 7 and 8). Affixed to the upper portion of the intermediate shaft extent 590, or otherwise within or below hopper 48 there may be at least one fluid pump P, which utilizes a screw-like rotor (not shown) and operable by rotation of auger device 59 to pump fluid material, such as cement mortar, granular materials, or mixes and the like, including sand. By rotation of auger device 59 within the large auger shaft 57, therefore, fluid material from hopper 48 is fed to pump P, which accelerates movement of the material through the large auger shaft in the open position of closure, shown in FIG. 7, which corresponds to the first incremental stop position of the larger auger as is shown and described above in connection with FIGS. 3 and 4. As before, the fluid sand may be forced into each cavity increment as shown in FIG. 7, in which the pressurized fluid material is being mixed and further compacted within the confined cavity space, by the rotating auger flight extent 59b. When each said cavity space has been compactly filled with material the closure 61 may be moved to closed position before starting upward movement of the larger auger, as shown in FIG. 8, or the small auger extent 59b may be extended and rotating in a manner to keep the filler material compacted. The segmental step process may be repeated as described until the desired upward extent of formed sand or other column is accomplished, at which time the small auger may be withdrawn to the closed position of closure 61, to accomplish full withdrawal of the largerauger without unnecessary loss of filler material.

Referring to FIGS. 9 and 10, there is illustrated modified form of the soil augering means best shown in FIG. 1, but in which a cutter plate or blade is mounted on the lowermost portion of the flighting 12f of large auger 12, to be selectively slidable toward and from a position in which a substantial extent of the blade will project into the earth of the situs, as shown in chain-dotted lines in FIG. 10, for enlarging the diameter of a substantial vertical extent 71- of the lower end of the cavity 18, by appropriate axial movement of the largeauger while being rotated in cavity boring direction (see FIGS. 9 and 10). For this purpose a hydraulically, actuated piston unit 72, mounted on the underside of the large auger flighting 12f, is selectively operable by suitable remote control means (not shown), to extend the blade 70 beyond the peripheral edge of said auger flighting 12f, as shown in chain-dotted lines in FIG. 10. The projected blade 70 is adapted, with appropriate rotation and axial movement of the large auger 12, to feed the materialscooped from the augered enlargement 71 up the large auger flighting 12f, for removal of the scooped material along with the earth 'core from the augered cavity 18. This feature makes it possible to form a concrete base or bulb 11d, in the enlarged cavity portion 71, which becomes an integral part of the completed concrete pile l1.

Furtherin reference to FIGS. 9 and 10, it is readily apparent that the blade 70 may be adjusted to extend beyond the cutting edge of the auger flighting a lesser extent than shown, as for example a fraction of an inch, thereby during rotative withdrawal of the large auger, to provide scoring or grooving on the walls of at least one of the cavity increment extents 18:. The subsequently formed and hardened concrete pile for example, by extension into the scores or grooves in the cavity walls will, by increasing the shear resistence of the hardened pile, increase the ultimate load bearing capacity of the pile correspondingly. This scoring procedure can be utilized in forming concrete piles by other methods utilizing hollow-shafted augers.-

In practice of the foregoing and related methods for producing concrete piles, load-bearing capacities of the finished piles may be substantially increased by, before or while pumping the fluid cement mortar into each closed cavity increment, forcing chemical or cement grout through the

small auger shafts

21 or 59 ,of FIGS. 2 and 7, respectively. The relatively more fluid grout is thereby displaced by the heavier pressurized cement mortar, and is forced into the cavity wall areas of the respective cavity extents to permeate radially into the surrounding earth, including fissures crevices and voids therein. The grout-permeated earth hardens substantially as integral reinforcing extensions of the hardened concrete piles, with very substantial increase in said pile load-bearing capacities. The degree of penetration of the more fluid grout will depend upon the permeability of the-surrounding soil, but is to a substantial degree measurable by the total amount of grout pumped into the cavity and/or the amounts pumped into the cavit increments.

In a modified use of the apparatus generally described above, and particularly as described above in reference to FIGS. 1 to 6, for producing columns of either self-hardenable cementitious material or porous materials, the following method procedure is calculated to produce highly satisfactory results. After screwing the larger auger into the situs to full depth of the cavity 1 8, the large auger is withdrawn by a plurality of separate incremental steps to successive stop positions-of the larger auger, as shown in FIGS. 4 and 5, each time at a given withdrawal speed while rotating the smaller auger 21 at a second rate of speed, calculated mechanically to force-feed the fluid material from the hopper axially into the respective cavity increment at a faster linear speed than the rate of withdrawal of the larger auger. As the larger auger is thus withdrawn toward any given said stop position, however, the continued relatively fast rotation of the smaller auger, including a substantial flighted extent thereof presented below the inner end of the larger auger (see FIGS. 4 and 5), force-feeds the fluid material into the corresponding cavity increment 18i, rapidly to fill the same to a point of refusal at which the fluid material becomes static in the large auger shaft passage 24, as well as in the supply hopper. Full of maximum compaction and densifying of the fluid material fed or conveyed into each closed cavity increment l8i will be readily discernible at each said point or period of refusal by observing an accompanying static condition of the material in the hopper, or by slight upward movement of the larger auger, after which the operation is repeated until the incremental column is completed, generally as shown in FIG. 1. In addition, the above-described force-feeding rotation of the smaller auger may be accompanied by reciprocation of the same to provide pumping action in the-discharged fluid material.

Modification of the invention may be resorted to without departing from the spirit of the invention or the scope of the appended claims.

. What is claimed is:

l. A method as for providing in an earth situs a column or structural formationof material different from that of the situs, comprising the steps of:

screwing a continuous flight auger into the situs to form a cavity therein of requisite depth; withdrawing said auger by successive incremental stages to stop positions of the auger defining a plurality of cavity increment extents in which the inner end of the auger is presented to the respective said cavity increment extent; and feeding fluid columnforming material into each successive said cavity increment extent, inupward progression, while the auger is in the corresponding said stop positions to fill the respective cavity increment extents, until the successive incremental extents of columnforming material form an integrated column of said selectivelength, the method including the step of adjusting cutter means on the inner end of said auger'radially outwardly thereof to form a radial enlargement of the cavity at the bottom thereof, which when filled with self-hardening cementitious said column-forming material, fed through the auger, provides a supporting base for said formed column to increase the load supporting capacity of the column. I

2. Apparatus for providing a pile or like body in an earth situs, comprising a spiral-flightscrew auger rotatable in the situs to define a cavity of requisite depth by upward movement of theaugered earth along the spiral flighting; cutter means operable with rotation of the auger for enlarging the cavity at the bottom thereof; and means for feeding self-hardenable cementitious material through. said auger to fill the cavity and enlargement therewith to a selective extent upwardly within the cavity; said cutter means including a blade shiftably mounted on the auger, and power means for shifting said blade to project beyond the cutting edge of the auger flighting; and said blade in projected position thereof being inclined substantially as a spiral dispersed extension of the spiral flighting, whereby earth from said cavity-enlargement tends to merge with said upwardly moved augered earth.

3. Apparatus for forming a pile or like body in an earth situs, comprising; a spiral flight screw auger rotatable in the situs to define a cavityof requisite depth by displacement of the augered earth; cutter means operable upon rotative withdrawal thereof with the auger from the augered cavity to score the wall thereof, and means for feeding self-hardenable cementitious material through said auger tofill the cavity including said scoring, upon withdrawal of the auger from the cavity, said cutter means being shiftably mounted on said auger, and means being provided for shifting said cutter means to project beyond the cutting edge o h au er fli htin Pa 3,807,184 Dated April 30, 1974 Inventor(s) Lee Turxlllo It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2 line 32 "event" should read ear tent Claim 2 line 45 "persed" should read H posed Signed and sealed this 1st day of October 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. C. MARSHALL DANN Attesting' Officer Commissioner of Patents FORM POJOSO (10,69) USCOMMDC 60376-P69 us GOVERNMENT PRINTING OFFICE: 930

Claims

1. A method as for providing in an earth situs a column or structural formation of material different from that of the situs, comprising the steps of: screwing a continuous flight auger into the situs to form a cavity therein of requisite depth; withdrawing said auger by successive incremental stages to stop positions of the auger defining a plurality of cavity increment extents in which the inner end of the auger is presented to the respective said cavity increment extent; and feeding fluid column-forming material into each successive said cavity increment extent, in upward progression, while the auger is in the corresponding said stop positions to fill the respective cavity increment extents, until the successive incremental extents of columnforming material form an integrated column of said selective length, the method including the step of adjusting cutter means on the inner end of said auger radially outwardly thereof to form a radial enlargement of the cavity at the bottom thereof, which when filled with self-hardening cementitious said columnforming material, fed through the auger, provides a supporting base for said formed column to increase the load supporting capacity of the column.

2. Apparatus for providing a pile or like body in an earth situs, comprising a spiral-flight screw auger rotatable in the situs to define a cavity of requisite depth by upward movement of the augered earth along the spiral flighting; cutter means operable with rotation of the auger for enlarging the cavity at the bottom thereof; and means for feeding self-hardenable cementitious material through said auger to fill the cavity and enlargement therewith to a selective extent upwardly within the cavity; said cutter means including a blade shiftably mounted on the auger, and power means for shifting said blade to project beyond the cutting edge of the auger flighting; and said blade in projected position thereof being inclined substantially as a spiral dispersed extension of the spiral flighting, whereby earth from said cavity enlargement tends to merge with said upwardly moved augered earth.

3. Apparatus for forming a pile or like body in an earth situs, comprising; a spiral flight screw auger rotatable in the situs to define a cavity of requisite depth by displacement of the augerEd earth; cutter means operable upon rotative withdrawal thereof from the augered cavity to score the wall thereof, and means for feeding self-hardenable cementitious material through said auger to fill the cavity including said scoring, upon withdrawal of the auger from the cavity, said cutter means being shiftably mounted on said auger, and means being provided for shifting said cutter means to project beyond the cutting edge of the auger flighting.