US3178893A - Pile and pile driving apparatus - Google Patents

Description

April 20, 1965 v. J. FIORE 3,17

FILE AND PILE DRIVING APPARATUS Filed Jan. 23, 1961 4 Sheets-Sheet 1 FIG.1

" mmvrm Vincent J. Fiore ATTORNEY April 20, 1965 Filed Jan. 25, 1961 v. J. FIORE 3,178,893

FILE AND PILE DRIVING APPARATUS 4 Sheets-Sheet 2 am INVENTOR. 21A

Vmcenr J. Flore ATTORNEY April 20, 1965 v. J. FIORE PILE AND PILE DRIVING APPARATUS 4 Sheets- -Sheet 3 Filed Jan. 23, 1961 JNVENTOR.

Vincent J. Fiore ATTORNEY April 20, 1965 v. J. FIORE 3,173,893

PILE AND PILE DRIVING APPARATUS Filed Jan. 23, 1961 4 Sheets-Sheet 4 INVENTOR.

24 BY Vincem J. Fiore ATTORNEY United States Patent 3,17 8,893 PILE AND PHJE DRIVING APPARATUS Vincent J. Fiore, New York, N.Y., assignor to Foundation Specialties, Inc., New York, N.Y. Filed Jan. 23, 1961, Ser. No. 84,057 14 Claims. (Cl. 6153) This invention relates to a method and apparatus for driving piles, and more specifically an apparatus and method of driving piles permitting the use of relatively short pile driving leads and the inspection of the pile when placed in the ground.

As it is not uncommon for piles to attain a length of 50, 75, 100 or more feet, it was heretofore necessary to employ relatively very long pile driving leads for sinking a requisite length of pile into the ground. At the present time such piles generally comprise H-bearing beams known to those skilled in the art as BP sections. These H-bearing piles or 13? sections are generally driven directly into the ground without casings by repeated blows of a hammer on the upper end thereof. Upon the completion of the driving of such piles it was heretofore virtually impossible to determine the condition of the buried pile as inspection thereof was rendered impossible. Consequently, neither deflection or plumbness of the pile as driven could be detected. For this reason building codes limit the loading which can be placed on a BP section of a given size driven in this manner. Also the pile driving leads required to drive the longer piles attained prohibited lengths.

An object of this invention is to provide a method and apparatus for driving or sinking piles of relatively very long length in a manner which permits the use of only relatively very short leads and also which permits inspection of the entire sunken length of the pile.

Another object of the invention is to provide for a novel pile driving apparatus comprising essentially a plurality of telescoping nested tubular shell sections of relatively thin gauge material which are adapted to be extended to form a casing for a cast-in-place pile.

Another object is to provide the adjacent sections of the nested tubular shell section with cooperating interlocking means when in the extended position thereof.

Still another object of this invention is to provide a novel mandrel for driving pile shell casings into the ground.

Still another object is to provide a pile driving arrangement wherein the impact of the driving hammer for a mandrel driven cast-in-place pile is applied at the bottom of a mandrel or driving core where the blows of the hammer are rendered the most effective.

Another object is to provide in a method for shelling up and/ or driving a combination shell and H-core for a cast-in-place pile into the ground with a minimum of pile driving leads.

The foregoing objects, other features and advantages are attained in accordance with this invention by a series of tubular shells of relative short sections assembled in concentrically disposed telescoping relationship with respect to one another and which shells are adapted to be driven from a nested retracted position to an extended position of desired length and including cooperating means on adjacent shell sections for interlocking the same with a slip joint in the extended position thereof. In accordance with this invention the shell section for receiving an H-bearing or BP section may be driven into the ground either by a novel bottom driven telescoping mandrel or driving core adapted to be received within the respective nested shells or by driving the telescoping shell casings and encased H-beam or pile simultaneously using the latter as the driving core. In driving the H-beam and shell casing simultaneously, with the pile functioning as the driving core, the telescoping casing may be either first drawn up to encase the beam or pile prior to driving, or the sections of the telescoping shell may be successively carried into the ground along with the beam as the interlocking means of the adjacent shells engage, as the pile is being driven.

A feature of this invention resides in the provision of a bottom driven telescoping mandrel which permits the core or mandrel sections to be formed of relatively light gauge material.

Another feature resides in the provision of a telescoping shell of a cast-in-place pile wherein the adjacent shell sections have cooperating means for interlocking the adjacent sections to form a slip joint therebetween in the extended position thereof.

Other features and advantages will become readily apparent when considered in view of the drawings and description thereof in which:

FIG. 1 is a fragmentary sectional view of the telescoping shell casing for a cast-in-place pile and telescoping mandrel for driving the same, both illustrated in the nested inoperative position.

FIG. 2 is a sectional view of the telescoping shell casing and mandrel therein, both illustrated in the operative extended position thereof.

FIG. 3 is a section view taken along line 33 of FIG. 1.

FIG. 4 illustrates a modified detail of the innermost core section of the mandrel shown in FIG. 2.

FIGS. 5 and 6 illustrate modified cross-sectional shapes which the respective tubular shells of the casing of FIGS. 1 and 2may take.

FIG. 7 is a modified detail of the cooperating means which form the slip joint between adjacent tubular sections of the pile casing of FIGS. 1 and 2.

FIG. 8 is still another modified showing of the slip joint between adjacent tubular sections of the shell casing.

FIG. 9 is a sectional view of the extended shell casing shown with an H-beam or pile section in position therein. FIG. 10 illustrates the telescoping casing in retracted inoperative position.

FIG. 11 illustrates the casing in extended operative positive with the H-beam or pile section disposed therein encased in concrete.

FIG. 12 is a bottom view of the drive shoe of the pile casing.

Referring to the drawings, the pile casing 20 in accordance with this invention comprises a plurality of tubular shell sections 21, 22, 23 concentrically arranged one within the other, which in the nested or retracted position thereof, as shown in FIGS. 1 and 10 constitute a relatively short column. In the illustrated embodiment of FIGS. 1 and 2, the shell casing 20 is formed of three cylindrical sections, i.e. the innermost or first shell section 21, a second shell section 22 and a third section 23. While only three such shell sections are illustrated it will be understood that any number of such shell sections may be concentrically disposed as may be required to attain a given predetermined extended length.

In the form of the invention shown in FIGS. 1 and 2, each shell section 21, 22, 23 is circular in cross-section and sized so that one slides within the other. Each of the shell sections adjacent its lower end is provided with an inwardly tapering frusto-conical outer surface 21A, 22A, 23A, respectively, to define an inwardly extending flange terminating in an upright annular skirt 21B, 22B, 23B spaced from the inner surface of the respective shells. Thus an annular open, upper end groove 21C, 22C, 23C is formed in the lower end of each shell section.

surface of the respective shells. Thus a downwardly open end groove 21F, 22F, 23F is formed exteriorly, about the upper end of each shell, respectively. a

As will be hereinafter described, the depending skirt 22E, 23E adajacent theupper end of shells 22, 23 respectively in constructed and arranged so as to be re ceived in the annular grooves 22C, 23C formed at the bottom of the next adjacent shell and the upwardly extending skirts 22B, 23B are arranged to project into the downwardly opening groove 22F, 23F to form aninterlocking slip joint between successive shells in the extended positions thereof, as seen in FIG. 2. a

As shown in FIG. 2, a drive shoe24 is" connected to the bottom of innermost shell 21 to lead the shell casings as they are being driven into the ground. The'drive shoe 24 is provided with an outwardly turned flange.

25 having a depending skirt 26 adapted to fit into the groove 21C adjacent the lower end of the inner shell section 21. The tip 24 of the shoe is provided with a pair of inverted V grooves crossing at right angles to provide sharp edges to facilitate driving the shell casings into the ground. See FIG. 12. shoe 24 may be formed as an integral part of the inner shellsection 21.

In accordance with this invention the shell casing 20 is adapted to be driven by means of a novel telescoping core or mandrel 30, or the shell casing may be driven as a combination shell and H-core pile (FIG. 9) to permit greater pile loading with lighter steel members or H-core.

As shown in FIGS. 1 and 2, the mandrel 30 is made up of a plurality of core sections 31, 32, 33, each concentrically disposed one within the other. In the illustrated embodiment, the mandrel 30 comprises an innermost core 31, an intermediate core section 32, and an outer core section 33. Generally the number of core sections equal the number of shell sections.

An important feature of this invention resides'in that If desired the drive portion 36 and the bumper head 39 isa guide shaft 40 for guiding the rise and fall of the hammer 34 slidably mounted therein and disposed within the inner core section 31. The hammer 34 issuspended from steel cables 41 connected to the upper end of the hammer 34, and

' which cables 41 extend upwardly through appropriate openings 42 in the bumper head 39 and connect to a swivel 43. The swivel 43 in turn connects to cable 44 .of the driving piston (not shown) for controlling the rise and fall of therhammer.

Preferably the space between the litter or bumper head 39 and anvil portion 36 should be approximately three (3) times the length ofthe hammer 34. Thus the length of the'inner or first shell section is determined by the overall length of the, hammer assembly 35. Also, it should be noted that the hammer or drive weight 34 is provided with a blocked edge at top and bottom; and the cables 41 connecting the hammer being secured thereto below its top surface.

The next adjacent core section 32 comprises a tubular core member having its lower end tapering inwardly at 32A to mate with the conical surface 31A adjacent the upper end of the inner core 31 and withthe inclined surface 21D of section 21 when in the extended position thereof, and the upper end of the core section 32 is also provided with an outwardly flared frusto-conical surface 32B.

The outer core section 33 islikewise similarly formed with an inwardly tapered lower end 33A'and an outwardly flared conical upper surface 33B.

In accordance with this invention each of the core sections 31, 32, 33 are slidably keyed one'to the other. This is attained by providng each of the core sections 31, 32,

the hammer 34 for driving the shell casings 21, 22, 23

Consequently the inner core section 31 is provided I at its lower end portion with an anvil portion 36 to receive the impact of the hammer 34, and the anvil portion 36 is adapted to be received in a 'well 37 formed in the upper end of the drive shoe 24. As shown the walls of the well 37 taper slightly outwardly to conform to the shape of the anvil portion 36.

If desired the anvil portion 36 may be formed either 7 as an integral part of the inner core section as seen in FIG. 2, or it may be rendered detachably connected thereto as shown in FIG. 4.

As shown in FIG. 4 the anvil portion 36' and lower end of ,the inner core 31 are formed withcooperating shoulders for keying the anvil 36' into the lower end of the inner core section 31 and the anvil portion 36' secured to inner core 31' by means of suitable fasteners 38 such as flushed, bolts and the like.

Adjacent itsupper end, the inner core section '31 is provided with an outwardly extending frusto-conical shoulder 31A to define an enlarged upper end portion 31B. Capping the top of the inner core section 31 is a bumper or lifted head 39. Extended between the anvil.

33 with longitudinal keyways 31c, 32c, 33c circumferentially spaced therearound. Preferably three or four such keyways on 90 or 120 spacing will suffice. Adapted to be received in each of the keyways is a key 45 connected by flush bolts to the inwardly tapered lower ends 32A, 33A of thenext adjacent core section.

If desired the wall of the inner core section or hammer assembly may be providedwith a series of perforations or openings 46 to allow for washing out in the event that mud or dirt enters therein as a result of the pile becoming damaged in driving.

If desired the shell sections may be provided with longitudinally extending flutes 47, 48 to provide shell sections 50, 51 with a cross-sectional shape as seen in FIGS. 5 and 6. The flutes 47, 48 may extend either the'entire length of the shell section, or they may terminate intermediate the length of the shell sections 50, 51. Thus, the fluted wall constructions of FIGS. 5 and 6 permit a shell section to be formed of still higher gauge material.

FIGS. 7 and 8 illustrate modified detailsof the slip joint construction between adjacent shell sections. In FIG. 8

' the depending skirt 60 of a modified inner shell section 61 and the upwardly extending skirt62 of the next outer shell section63 are taperedrinwardly in the direction of their freeend. Thus a wedging action is attained in forming the interlock as the respective shell sections are extended.

In FIG. 7, the respective skirts70 and 71 of an inner and next adjacent outer shell 72, 73, respectively, have complementary irregular or joggled surfaces to provide a more positive interlocking arrangement between the respective shell in the extended position.

As shown in FIGS. 7 and 8,- a suitable packing gland V or gasket 80, 81 may be positioned in the bottom of the annular groove defined by the respective skirts and the wall of its respective shell section to provide for a more positive' seal against the seepage of any water into the shell in the event'water is present during a pile driving operation.

In field operation the telescoping mandrelv 30 described eliminates many of the difliculties thatheretofore'arose in driving long shell piles, chiefly among which was the shelling up of the presently known mandrels which in themselves are required to equal the length of the pile casing to be driven. In such instances the leads required attained enormous lengths which in all cases had to be as long as the mandrel length plus the additional lead above the mandrel for the driving hammer.

Thus with the construction herein described piles of extra long lengths can be driven with the use of relatively very short leads, since the initial length of the mandrel St? is only a fraction of that otherwise required. Also the construction described is provided with a guide shaft 49 sufficiently long to allow for additional rise and fall of the hammer to create greater foot pounds of energy without requiring interchanging hammers.

In operation the nested shell sections 20 are placed in a suitable carriage to hold the assembled shell sections in place while driving, which carriage also prevents the following sections from entering the ground until the cooperating skirts or slip joints of adjacent shell sections are engaged. The telescoped mandrel 30 is then placed in position within the nested shell sections 20 and the cables 44 for operating the hammer secured. Accordingly the hammer is operated so that its impact or force is applied at the bottom of the core or mandrel. Upon the driving or complete extension of the nested shell sections, the mandrel is removed and an H-beam column 84 is placed within the sunken shell sections. In this manner the plumbness of the beam 84 is assured, and can be loaded to its designed specification. Also to increase its load bearing characteristics, the beam may be embedded in concrete 85 as shown in FIG. 11.

As an alternate method, the telescoping shell sections 20 may be driven as a combination shell and H-core pile. In accordance with this method the H-pile 84- is placed in its leads and positioned into the nested, shell sections with the bottom of the pile seated in the well 3'7 of the drive boot 24. The shell is then drawn up to encase the steel pile 84 with the respective slip joints interlocking as the shell is pulled up. After shelling, the pile 84 is then driven nnto the ground with the H-beam acting as the core for driving. See FIG. 9.

If desired the shelling up step of the pile may be eliminated from the preceding method, in which case the driving of the H-beam 84 will successively carry down the respective sections of the shell casing as the slip joints engage.

While the instant invention has been disclosed with reference to a particular embodiment thereof, it is to be appreciated that the invention is not to be taken as limited to all of the details thereof as modifications and variations thereof may be made without departing from the spirit or scope of the invention.

What is claimed is:

1. A pile casing comprising a plurality of nested telescoping tubular shell sections adapted to be extended to a predetermined length and including a lead shell section, a drive shoe connected to the lead shell section, and means for successively extending the shell sections into the ground, said means including a mandrel having a plurality of nested telescoping tubular core sections adapted to be received within said shell sections, said core sections including a first core section the bottom of which is adapted to engage said drive shoe, a hammering means movably mounted in said first core section whereby the force of said hammer is applied at the bottom of said first core section and each of said core sections and corresponding shell sections having cooperating shoulder portions for maintaining the respective she-ll sections in compression and for transmitting driving force applied by said hammer through the extended core sections to the corresponding shell sections so that the respective shell sections successively follow the corresponding mandrel core sections as the latter are driven into the ground during a driving operation.

2.. A pile casing comprising a plurality of nested, concentrically disposed, telescoping, tubular shell sections adapted to be extended between nested inoperative position and an extended operative position, a drive shoe connected to the innermost shell section, drive means for successively extending the respective shell sections and sinking the same into the ground, and the adjacent she'll sections of said nested sections having cooperating means to form an interlocking slip joint therebetween as each shell section is successively extended to its operative extended position and said driving means including a mandrel having a plurality of core sections corresponding in number to said shell sections, and said core sections and corresponding shell sections having cooperating shoulders for maintaining said shell sections in compression when extended during a driving operation.

3. The invention as defined in claim 2 wherein each of said shell sections have an outwardly extending flange adjacent the upper end thereof, said outwardly extending flange having a depending skirt spaced from the outer surface of said shell, and an inwardly extending flange adjacent the lower end of said shell, said inwardly extending flange having an upwardly extending skirt spaced from the inner surface of said shell.

4. The invention as defined in claim 3 wherein said cooperating skirts are tapered to provide wedging action between the cooperating surfaces of said slip joint.

5. The invention as defined in claim 3 wherein said cooperating skirts are joggled to provide an interlocking slip joint.

6. A pile casing comprising nested telescoping tubular shells including an innermost shell and a concentrically disposed outer shell, each of the said shells having an inwardly extended flange and connected upright skirt spaced from the inner surface of said shell adjacent the lower end thereof and an outwardly extended flange having a connected depending skirt spaced from the outer surface of said shell adjacent the upper end thereof whereby the flange and connected skirt adjacent the upper end of one shell cooperates with the flange and connected skirt adjacent the lower end of the adjacent outer shell in the extended position thereof to form a slip joint therebetween, and means for successively driving each of said shells into the ground, said means including a mandrel having telescoping core sections adapted to be received within said shells, said core sections including an innermost tubular core section and a concentrically disposed outer tubular core section corresponding to said shell sections, means slidably connecting adjacent core sections together, each of said core sections having an inturned shoulder adjacent the lower end thereof, said inturned shoulder being adapted to engage the outwardly extended flange of a corresponding shell section, and each of said core sections having an outwardly turned shoulder adjacent the upper end thereof arranged to engage the inturned shoulder of the next adjacent core section in extended position thereof, and means for successively extending each of said core sections and corresponding shell sections, said latter means including a hammer movably mounted within said innermost core section so that the force of said hammer is applied directly to the bottom of said innermost core whereby the force applied is transmitted to the succeeding core sections for driving each of said core sections and its respective shell, said force being transmitted through said cooperating inturned and out-turned shoulders of adjacent core sections to maintain the respective shell sections in compression during a driving operation.

7. A pile casing comprising a plurality of nested telescoping tubular shells including an innermost shell and a plurality of concentrically disposed outer shells, each of the said shells having its lower end tapering inwardly and terminating in an inwardly extending flange with an upright skirt spaced from the inner surface thereof, and an outwardly extending flange terminating in a depending skirt spaced from the outer wall of said shell adjacent 7 the upper end thereof whereby the ,flange adjacent the ripper end of one shell cooperates with the flange -ad jacent the lower end of the next adjacent outer shell in the extended position thereof to form a slip joint the-re between, a drive shoe connected to the lower end of the innermost shell, and means for successively sinking each of said shells into .the ground, said means including a telescoping mandrel adapted to be received within said shells, said mandrel including an innermost tubular section and a plurality of concentrically disposed outer tubular sections, said mandrel sections adapted'to correspond with'each of said shell-s, said respective mandrel sections and corresponding shell sections having cooperating shoulders for maintaining said shell sections in compression when extended, means for slidably'connecting adjacent mandrel sections, and means for successively extending each of saidmandrel sections and corresponding shell, said latter means including a hammer movably mounted Within said inner-most core section whereby the.

force of said hammer is applied directly to the bottom of said innermost mandrel section tor driving each of said mandrel sections and the torce applied being transmitted through the respective mandrel sections to the corresponding shell sections and to its corresponding shell whereby they are successively sunk with the respective mandrel sections as the latter are being driven into the ground.

'8. The invention as defined in claim 7'whereine-ach mandrel section is provided with a plurality of'circumcferentially spaced longitudinally extending keyway grooves formed in the outer surfacethereof, and a cooperating key adapted to be received in said grooves connected to the next adjacent outer mandrel section.

-9. The invention as defined in claim 8 whereinthe outer surface of each mandrel section is provided with an outwardly flaring shoulder surface adjacent the upper end thereof and an inwardly extending'shoulder surface adjacent the lower end thereof whereby the outwardly flaring surface of the inner mandrel cooperates with the inwardly extending shoulder surface adjacent the lower end of the next adjacent outer mandrel section in the ex:

tended operative position of said mandrel so that the.

force applied to one mandrel section is transmitted to the other in the extended position thereof.

'10. A telescoping mandrel for driving a pile casing comprising a plurality of nested telescoping tubular cOTe sections including inner core sections and an outer concentrically disposed core section, cooperating shoulder means formed on said core sections engage-able to limit slidably connecting means including a key and complementary keyway formed on said inner and outer core sections, and a driving means disposed and confined of said core section. I

1 2. A telescoping mandrel for driving'pile casing into the ground comprising a plurality of tubular nested te escoping core sections including an inner core and a plurality of outer concentrically disposed core sections, each of said tubular core sections having an inwardly tapering lower end and an outwardly flaring upper end whereby the flaring upper end of the inner core cooperates the inwardly tapering lower end of the next adjacent outer. core section in the extended position of said sections, means for slidably connecting said inner core section relative to the next adjacent outer core section, said sliding means including a key connected to one of said core sections and a keyway for receiving said key disposed in the surface of the other of said core sections, and a hammering means disposed Within said inner core section, said hammering means including a hammer reciprocally mounted and housed in said inner core, a guide means for guiding the rise and fall of said hammer within said inner core section so that the force of said ham mer in driving said mandrel is applied directly to the bottom of the inner core so that said bottom driving of said mandrel allows said core section to be formed of relatively thin gauge material.

13. A pile casing comprising a plurality of nested telescoping tubular shell sections adapted to be extended between an inoperative nested position and an extended operative position, andmeans for successively extending said nested shell sections into the ground, said means including a mandrel having a plurality of nested core sections corresponding with said shell sections whereby the extension therebetween, means for slidably connecting the inner core section within said outer core section, said each of the respective core sections is adapted to be received within a corresponding shell sect-ion, said core sections and corresponding shell sections having cooperating means adjacent the upper and lower ends thereof for, maintaining the shell section being extended in compression during a driving operation, and a hammer means movably, mounted and confined within the inner-most core sect-ion whereby the force of said hammer is applied at the bottom of said inner-most core section for extending the respective shells, and said force being transmitted through the extended core 'sections'to the corresponding extended shell sections as the latter arebeing extended into the ground.

14. A pile casing comprising a plurality of nested telescoping tubular. shell sections, means interconnecting adjacent nested shell'sections to extend the same between inoperative nested position and extended operative position, and means for successively driving each of said shell sections into the ground, said means including a mandrel having a plurality of nested telescoping tubular core sections adapted to correspond with and be received within said shell sections'respectively, said core sections and their respective shell sections having cooperating shoulders for maintaining said shell sections in compression when extendedduring a. driving operation, and said core sections including a first core section, and a hammering means movably mounted in said first core section so that the force of said. hammer is applied at the bottom of said fiist core section.

References Cited by the EXflmiHeI'. UNITED STATES PATENTS 1,342,424 6/20 Cotten 61-5364 1,771,312 7/30 Pierce 6l53.-52 1,872,688. 8/32 Dealy ole-53.72 2,036,355 4/36 Orr et a1. 61-53.52 2,371,784 3/45 Titcomb et a1. 6l-53'.7 2,528,999 11/50 Bruns 6l-53.62 2,693,087 11/54 Quillinan 61--53.7 2,875,584 3/59 Turzillo 61--53.62 X

. FOREIGN PATENTS V 65 12/ 13 Netherlands.

330,536 12/20 Germany.

215,177 5/24 Great Britain.

BENJAMIN BENDETT, Primary Examiner.

WILLIAM I. MUSHAKE, JACOB SHAPIRO, JACOB L. NACKENOFF, Examiners.

Claims (1)

1. A PILE CASING COMPRISING A PLURALITY OF NESTED TELESCOPING TUBULAR SHELL SECTIONS ADAPTED TO BE EXTENDED TO A PREDETERMINED LENGTH AND INCLUDING A LEAD SHELL SECTION, A DRIVE SHOE CONNECTED TO THE LEAD SHELL SECTION, AND MEANS FOR SUCCESSIVELY EXTENDING THE SHELL SECTIONS INTO THE GROUND, SAID MEANS INCLUDING A MANDREL HAVING A PLURALITY OF NESTED TELESCOPING TUBULAR CORE SECTIONS ADAPTED TO BE RECEIVED WITHIN SAID SHELL SECTIONS, SAID CORE SECTIONS INCLUDING A FIRST CORE SECTION THE BOTTOM OF WHICH IS ADAPTED TO ENGAGE SAID DRIVE SHOE, A HAMMERING MEANS MOVABLY MOUNTED IN SAID FIRST CORE SECTION WHEREBY BY FORCE OF SAID HAMMER IS APPLIED AT THE BOTTOM OF SAID FIRST CORE SECTION AND EACH OF SAID CORE SECTIONS AND CORRESPONDING SHELL SECTIONS HAVING COOPERATING SHOULDER PORTIONS FOR MAINTAINING THE RESPECTIVE SHELL SECTIONS IN COMPRESSION AND FOR TRANSMITTING DRIVING FORCE APPLIED BY SAID HAMMER THROUGH THE EXTENDED CORE SECTIONS TO THE CORRESPONDING SHELL SECTIONS SO THAT THE RESPECTIVE SHELL SECTIONS SUCCESSIVELY FOLLOW THE CORRESPONDING MANDREL CORE SECTIONS AS THE LATTER ARE DRIVEN INTO THE GROUND DURING A DRIVING OPERATION.

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