US3303656A

US3303656A - Method and apparatus for constructing columns of material in soil

Info

Publication number: US3303656A
Application number: US246411A
Authority: US
Inventors: Richard E Landau
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-12-21
Filing date: 1962-12-21
Publication date: 1967-02-14
Anticipated expiration: 1984-02-14

Description

Feb. 14, 1967 R. E. LANDAU 3,3 56

METHOD AND APPARATUS FOR CONSTRUCTING COLUMNS 0F MATERIAL IN SOIL Filed Dec. 21, 1962 3 Sheets-Sheet l INVENTOR 23s RICHARD E.LANDAU 1967 R. E. LANDAU 3,303,556

METHOD AND APPARATUS FOR CONSTRUCTING COLUMNS OF MATERIAL IN SOIL Filed Dec. 21, 1962 5 Sheets-Sheet 2 z 'a. viii/ 1191;

F l G .10

F l G .3

use 148 I46 9 INVENTOR RICHARD E. LANDAU Feb. 14, 1967 R. E. LANDAU 3,303,656 METHOD AND APPARATUS FOR CONSTRUCTING COLUMNS 01? MATERIAL IN sou Filed Dec. 21, 1962 s Sheets-Sheet a A E J. N i

F I G .4 270 42 275 O 262 25a 2 L J {I #34 J L. --27o E1 V 9 i g F I 'l INVENTOR N U '2 RICHARDE LA DA United States Patent 3,303,656 METHOD AND APPARATUS FOR CONSTRUCTING COLUMNS OF MATERIAL IN SOIL Richard E. Landau, Middle Village, N.Y. (717 Cornwell Ave., West Hempstead, N.Y. 11552) Filed Dec. 21, 1962, Ser. No. 246,411 14 Claims. (Cl. 6163) The present invention relates to construction methods and apparatus, and, more particularly, to novel methods and mechanisms for installing columns of material in soils.

In construction of structures such as bridges, highways and buildings, it is often necessary to consolidate the soil on which these structures are to be placed by draining the soil of undesirable sub-surface water to ensure proper soil support therefor. Stabilization is usually accomplished by placing vertical columns of highly permeable material, such as coarse sand, at spaced intervals into the soil to be consolidated.

Heretofore, this has been done by driving or forcing a hollow mandrel or casing into the soil formation to be consolidated, filling the casing with porous material, and then withdrawing the casing to leave a column of material in the soil. As discussed more fully in my copending application, Serial No. 746,099, filed July 2, 195 8, and now Patent No. 3,096,622, the driving and subsequent pulling of the mandrel or casing results in smearing of the face of the soil void to be drained in contact with the mandrels outer surface. In addition, the driving of the mandrel or casing re-molds the soil in the u vicinity of the cavity. The smearing and re-molding inherent in the placement of said drains by driving results in a substantial decrease in the consolidation rate of the soil and in a reduction of the soil strength. In addition, driving a mandrel may also result in movement of the soil displaced thereby so as to effect a shearing of previously-installed columns or drains, thus destroying their usefulness.

In other construction techniques, the structures, such as bridge abutments and buildings, are supported by piles or pillars of concrete or like material rather than directly by the soil. Heretofore, cast-in-place piles were formed, as with sand drains, by driving an outer mandrel into the soil, filling such soil with concrete, and when the concrete had set or hardened sufiiciently, the mandrel could be withdrawn, if desired, or left in the cavity as a pile housing. However, non-displacement piles are particularly useful in foundation work where care must be taken not to disturb or damage adjacent structures or prior-placed piles by driving of piles or mandrels.

It is an object of the present invention to provide novel methods and mechanisms for placing columns of material in soil formations without displacing, smearing, remolding or otherwise disturbing the soil.

One aspect of the present invention is characterized by the provision of a novel apparatus for the placing of drains or columns of porous material in soils. In such a device, a hollow shaft, continual-flight auger is employed, which cuts into the soil formation to the desired depth. By suitably cutting into the soil formation rather than disturbing the soil, as by driving a mandrel, the soil formation is neither displaced nor re-molded, nor, in the case of varved soils, is the soil smeared. The auger is provided at its leading end with a cap member remov able when the auger is withdrawn to admit the sand or other porous material into the cavity to form the drain as the auger is withdrawn. To supply the drain material to the auger, there is mounted thereon at the end of the auger remote from the cap a housing which holds the volume of material required by the drain. To ensure a free flow of the materal, the housing or hopper is provided with a pneumatic pressure system having one outlet adjacent the entry of the material from the housing into the auger. The pressure system prevents interruption of material feed and ensures a steady supply of material to the auger. This precludes any possibility of voids developing in the drain by an interruption of drain material feed, and results in the formation of a continuous column of material in the soil having a uniform dimension and shape.

Means are also provided for replacing the auger cap with a drill element when obstructions such as boulders are encountered, or to permit the taking of soil samples at a selected depth. This drill element may be separately rotatable or rotatable with the auger. Likewise, a vibrator, if desired, can be inserted into the material after placement in the cavity to densify the columnar material, or the vibrator can be employed to settle and densify the soil formation adjacent to the auger either by insertion into the auger section in contact with the soil.

In one embodiment of the present invention, there is provided a novel device for forming non-displacing piles directly in place in the soil formation. In this embodi ment of the invention, there is provided a second auger rotatably mounted inside the hopper or housing, and preferably extending into the inside of the outer auger. Concrete is placed in the housing and, as the outer auger and any internal mechanism are withdrawn to form the cavity, the second auger i rotated to feed concrete into the cavity. This arrangement provides a positive feed for the concrete or other material where homogeneity is desired and segregation of its component materials is to be avoided.

By utilizing an internal auger to feed the concrete, it is assured that the concrete is positively placed in the cavity to form a continuous column without incurring harmful segregation of particles. Likewise, the present arrangement permit the use of concrete having the conventional aggregate size. This results in a stronger, more economical, shell-less concrete pile than heretofore, where grout mixtures have been used containing only fine aggregate.

To provide for vibration of the pile material, the second auger can also be of the hollow-center shaft type. In this case, a vibrator can be connected to or inserted through the second auger shaft to vibrate and densify the pile material at it is placed into the cavity or immediately thereafter.

As in the first-described embodiment, a drill element may be included to penetrate any rock formation and to provide proper seating of the pile, if such is desired.

In each embodiment of the invention, means is disclosed which may be utilized for effecting rapid coupling and uncoupling of successive sections of anger shaft. The contiguous ends of the auger shafts to be joined are provided with matching teeth and are threaded in opposite directions; that is, one shaft has a right-handed thread while the second shaft has a left-handed thread. The coupling for the auger shafts is also provided with two corresponding sets of opposite threads. The shafts are aligned in the coupling, and the coupling rotated to draw the shafts together, mating the teeth of the shafts. This coupling arrangement produces a joint of high torque and tension capacity, which does not continue to tighten upon rotation of the augers, and can be easily uncoupled without great force.

Novel means are also provided for safely conveying cavity material to the auger hopper or housing. The hopper is usually loaded when the auger is in its elevated position. To convey the material to the elevated housing, there is provided a vertically-travelling, tiltable conveyor. When the conveyor reaches the elevated housing, the conveyor is pivoted into feeding position to permit passage of the cavity material from the conveyor into the housing. Stop means is employed to ensure that the conveyor and housing, when in feeding position, maintain their respective relative feeding positions.

The auger and drive system are normally freely suspended. However, if desired, these members can be positively urged as by pulling as they travel on their supporting structures. In soft, wet, clay-like or organic-type soils, the auger and its appended equipment may penetrate the soil at an excessive rate by plunging under its own weight through these soil formations which offer little resistance, thereby causing smearing or other undesirable effects. To avoid this problem and control the maximum rate of travel of the auger to preferably a penetration rate of one pitch length per auger revolution with a helical auger flight configuration, a novel pivotable tooth device is utilized. The tooth is disposed between successive auger flights adjacent the entry of the auger into the soil. In hard strata, such as sands, gravels and other granular soils, the rate of auger penetration decreases below the desired rate, and the tooth is pivoted upwardly out of its normal horizontal position. However, the tooth is pivotal only in the upward direction. Thus, when the auger penetration rate tends to increase above the desired rate, the tooth resists such penetration so that the pivotal tooth ensures that the auger penetration does not exceed the desired rate.

The control tooth also services to remove any soil adhering to the auger flight as it moves therepast, and an air jet can also be employed to assist the tooth in cleaning the auger flight.

Objects and advantages of the invention will be obvious herefrom, or may be learned by practice with the invention, the same being realized and attained by means of the instrumentalities and combinations pointed out in the appended claims.

The invention consists in the novel parts, constructions, arrangements, combinations and improvements herein shown and described.

The accompanying drawings, referred to herein and constituting a part hereof, illustrate one embodiment of the invention and together with the description, serve to explain the principles of the invention.

FIG. 1 is a side elevation, partly in section, of one embodiment of the present invention.

FIG. 2 is a sectional view, taken along line 2-2, FIG. 1.

FIG. 3 is a side sectional view of another embodiment of the invention.

FIG. 4 is a side elevation of the auguer penetration rate control device.

FIG. 5 is a sectional view, taken along line 5-5, FIG. 4.

FIG. 6 is a side elevation, partly in section, of a third embodiment of the invention.

FIG. 7 illustrates one form of cap suitable for use in the present invention, together with a suitable soil samp e.

FIG. 8 illustrates another form of suitable cap.

FIGS. 9 and 10 illustrate two forms of suitable embodiments of shaft coupling means for use in the present invention.

FIG. 11 illustrates a suitable form of vibrato-r for use in the present invention.

FIG. 12 illustrates a suitable form of drill bit for use in the present invention.

Turning to the drawings, and particularly to FIGS. 1 and 2, there is illustrated an embodiment of the present invention having particular application to the installation of sand drains.

The invention comprises a hollow shaft auger 10 having an essentially continuous flute or flight 12, preferably helical in configuration. It will be understood that flight 12 can have spaced intervals therein, as when a succession of short length auger elements are employed, as discussed hereinbelow. The only requirement is that flight 12 be sufficiently continuous so as to provide segmental support for the soil engaged thereby. Shaft 10 has a hollow interior 14 of generally cylindrical cross-section and is secured at its upper terminus to a storage and feed hopper 16. Hopper 16 has a hollow interior 17 also and tapers as at 18 for connection to auger 10 as by a flange and bolt arrangement 20. The interior 17 of hopper 16 communicates with the interior 14 of auger 10 to effect passage of material from hopper 16 into auger 10.

To effect a cutting entry of auger 10 into the soil, there is provided means for rotating auger 10. Rotation of auger 10 effects its screw-like entry into the soil. To rotate auger 10, hopper 16, which is rotatable with auger 10, is provided at its upper terminus with a flange 22 bolted to a corresponding flange 24 mounted for rotation with hollow drive shaft 26.

Shaft 26 is mounted in suitable bearings in gear reducer unit 28, in turn driven from a suitable source of power such as motor 30. It will be understood that, thus, motor 38, through gear reducer 28, drive shaft 26 and housing 16, effects rotation of anger 10 for cutting into the soil.

In normal practice, the drains installed with the present invention may vary in length from ten feet or shorter to over one hundred feet in length. Thus, as anger 10 is rotated and makes its entry into the soil, means must be provided for supporting auger 10 and its associated mechanism for travel to the desired depth in the soil.

Accordingly, gear reducer 28 is mounted on a traveling carriage 32 which includes a support plate 34 braced at each side by struts 36.

Members

34 and 36 are fixed to a pair of spaced channel members 38 and 40, each adapted by a plurality of wheels 42, for travel along its

respective lead members

44 and 46.

To ensure rigidity, leads 44 and 46 are interconnected by spaced braces 4, while carriage channels 38 and 40 are braced by spaced cross-struts 50.

Plate 34 has on each side thereof a cable eye 52 accommodating an auger support cable 54 adapting the auger 10 and its associated mechanism for elevation to the desired height from a suitable source such as a lifting crane. It will be understood that, during the cutting operation, the tension in the cables 54 is relieved and the entire auger weight supported on the leading end thereof. However, it is desirable that cables 54 remain connected to plate 34 as a safety measure.

The leading or cutting end 56 of auger 10 is preferably provided with a retrievable, removable cap member 58 (see FIGS. 7 and 8). Cap 58 is preferably of the friction type and includes a cap plate 60, preferably circular and of a diameter approximately equal to the outside diameter of shaft 10. Cap plate 60 is provided on the inner face 62 thereof with a locking unit 64, including a gasket 66 disposed between and connected to a pair of relatively

movable plates

68 and 70. Plate 70 is fixed to face 62. A threaded bolt 72 is freely accommodated in cooperating recesses 69 and 71 in

plates

68 and 70, respectively. One end of bolt 72 is threadedly engaged in a threaded aperture 73 in plate 60, and passes freely into a central opening 75 provided in cutter member 74. The terminal end of bolt 72 in opening 75 is provided with a suitable actuating slot 77 for effecting rotation of bolt 72 to suitably travel the bolt through plate 60. Since bolt 72 has a flange 76 supported on plate 68, travel of bolt 72 in plate 60 in the direction of the arrow, FIG. 7, effects relative movement of plates 63 and 70 toward each other, expanding gasket 66 thereby.

In operation, cap 58 is seated against the bottom of auger 10 with gasket 66 and

plates

68 and 70 disposed inside auger 10. Alignment pins 78 on auger 10 and cooperating recesses 80 in plate 60 ensure proper align ment of cap 58 on auger 10. Bolt 72 is then rotated by means of slot 77 to expand gasket 66 into frictional en gagement with the inside periphery of auger 10. Bolt 72 is rotated until the desired amount of frictional engagement between gasket 66 and auger 10 is accom-t plished. To improve resistance against removal of cap 58, seated in auger 10, from gravity or soil suction during the cutting operation, a suitable support ridge or shoulder 82 is formed on the inside periphery of auger (see FIG. 7). Chain 84, fixed to auger 10 and cap 58, permits retrieval of the cap with the auger 10 as the latter is extracted from the soil at the end of the drain installation.

To facilitate entry and travel of auger 10 in the soil, leading end 11 of flight 12 and cap 58 are provided with exterior cutters 86.

FIG. 8 discloses an alternative cap structure, utilizing a cap plate 88 having a spring-return air cylinder 90 mounted thereon. Piston rod 92 of cylinder 90 acts as a latching device and normally rests in latching position on an abutment 94 fixed to auger 10 as shown, and accommodated in a recess 96 in plate 88. Plate 88 also includes a concave element 98 thereon, accommodating a mating convex element 100 on the inside of auger 10 to define a joint of pivot point 104 for plate 88 as it is released when cylinder 90 is appropriately actuated through line 102 as described hereinbelow to withdraw piston 92 from latching position. Chain 106, fixed to auger 10 and member 98, permits retrieval of the cap at the end of the drain installation.

In operation, auger 10 is positioned over the desired location for the drain column with auger 10 and hopper 16 in raised position at the start of the cutting operation. Auger 10 with its helical flight 12 is rotated by means hereinbefore set forth and makes its cutting entry into the soil with cap 58 in position in auger 10 to prevent entry of soil into the hollow auger as it is travelled thereinto. It has been found desirable that the auger penetration rate be one pitch length per revolution for soft soils, such as wet, clay-like or organic-type soils. Auger 10 is rotated, penetrating the soil until the desired depth is reached by the leading end thereof.

It will be understood that by helically cutting into the soil formation by means of continuous helical flight 12, smearing, re-molding and disturbance of the soil is minimized during the cutting operation.

At the desired depth, the auger is preferably rotated in place at least one complete revolution. This in-place rotation gently cuts a column or core of soil C defined by the periphery of flight 12 from the remaining soil formation. The auger is then withdrawn from the soil formation as by pulling through cables 54 to remove this soil core C from the remaining formation.

To replace the soil core thus removed, means is provided for feeding porous drain material M, such as coarse sand, from hopper 16 through interior 14 of shaft 10. As auger 10 is withdrawn carrying with it the soil core, the porous material M is fed from the leading or cutting end 56 of the auger 10 to replace the soil from the cavity and thus form the drain. In this manner, the formed cavity is always completely supported, either by auger 10 with core C or by the material M deposited therein.

To supply the porous material to auger 10, hopper 16 acts as a storage bin therefor, material M being fed in at least one embodiment by gravity from the interior of hopper 16 into and through the interior of auger 10 to the leading or cutting end 56 thereof. It will be understood that when cap 58 is utilized, as the auger 10 is withdrawn the weight of the column of material in auger 10 overcomes the frictional resistance of gasket 66, pushing the cap 58 out of closing position in auger 10 into open material-releasing position shown in FIGS. 4 and 7. Thus, the material in auger 10 freely exits therefrom into the soil cavity, filling the cavity simultaneously with the withdrawal of the auger and in response thereto.

Porous material, such as coarse sand, exhibits a pecu liar phenomenon generally referred to as arching; that is, the sand, due to its natural coefficient of internal friction, resists free gravity flow from a larger area into a more restricted passage and ends to form a bridge or arch across such passage generally along a line as shown in dotted lines, FIG. 1. When such arches are formed, the flow of material is interrupted.

To prevent the formation of such arches and ensure continuous free gravitational flow of the porous drain material from hopper 16 into and through auger 10, and hence int-o the soil cavity, means is provided for breaking and/or preventing the formation of such arches. This means includes an air outlet nozzle 108 disposed inside hopper 16 adjacent one wall thereof and adapted to -re= lease air under pressure against the drain material adjacent the dotted arch line. The air under pressure breaks any arch already formed and prevents the formation of any new ones, as well as those that might form in shaft 11.

The air to nozzle 108 is fed from a pneumatic system associated with hopper 16, which not only controls the air to nozzle 108, but also effects the opening and closing of the access entry to hopper 16, pressurizes the upper surface of the soil material to prevent upward travel of air from nozzle 108, and which can, if desired, operate vibrator means to assist the flow of material from hopper 16 into auger 10 and control the operation of cylinder to release the cap illustrated in FIG. 8.

It has been found that, in some instances, the weight of the material column in auger 10 has not been sufficient to effect movement of cap 58 out of auger 10 into its open material-releasing position. However, it was further found that by utilizing a pneumatic nozzle, such as 108, in the lower section of hopper 16 to prevent formation of arches, the pressure exerted by nozzle 108 also was, in effect, transmitted through the voids inherent in the porous material M in auger 10, such that nozzle 108 assisted the column of material M in auger 10 to effect release of frictional cap 58.

In the embodiment shown in FIG. 1, nozzle 108 is fed from a pneumatic line 112 supported on the interior surface of hopper 16 by a bracket 114. Line 112 is connected through a suitable check valve 118 to a main air pressure line comprising a hollow shaft or pipe 120 seated concentrically within drive shaft 26. Air shaft 120 is mounted intermediate its length in a plate 122 disposed between

flanges

22 and 24. Plate 122 completely closes olf the top of hopper 16 (see FIG. 3) which, with annular gasket 124, thus forms a sealed upper enclosure 126 for housing 16. An outlet nozzle 116 in line 112 located above the maximum level of material in hopper 16 effects pressurization of the sealed upper portion of hopper 16 simultaneously with the release of air from nozzle 108. The pressurization of the upper portion of hopper 16 is desirable to prevent any blowback of material from nozzle 108. It is desirable to thus prevent blow-back since this avoids entrappment of an excess of air in the material M. It has been found that

nozzles

108 and 116 should be no more than one-half inch in diameter when a two inch cylinder 146 is fed by a one-quarter inch diameter line 158 with air supplied from a six hundred cubic feet per minute compressor.

The material intake port for hopper 16 is best shown in FIG. 3 and reference will be made thereto. However, it will be understood that the construction and operation of the hopper intake port is essentially the same for all the embodiments of the invention where air pressure is utilized to maintain continuous flow of material from hopper 16 into auger 10.

The hopper intake port includes an access opening 128 in the upper tapered section 130 of hopper 16 provided with a flange 132 and sealing gasket 134. A door 136 pivotally mounted on pin 138, carried by spaced brackets 140 (only one of which is shown), is adapted for rotatable movement into operative closed position against gasket 134, as shown in full lines, FIG. 3, from a non-operative open or admitting position shown in phantom in FIG. 3.

Spring 142, secured at one end to a bolt 144 in hopper 16 and at its other end to door 136, normally maintains door 136 in open position to provide ready access to hopper 16. To close door 136, there is provided a suitable, single-acting, spring-return air cylinder 146 pivotally secured at 148 to, the iner face of hopper 16 at the section opposite opening 128. The free end of the cylinder piston is pivotal-ly secured to door 136 by pin 152.

After hopper 16 has been filled with porous drain material M as described hereinbelow, the main air control valve 110, which is preferably a three-way valve having one side connected to atmosphere, is actuated to admit air under pressure from a suitable source (not shown) into the system. The air under pressure enters shaft 120 through swivel 154.

In the embodiment shown in FIG. 1, air from shaft 128 passes directly into line 112 through check valve 118 and substantially simultaneously exits through nozzle 108 and outlet 116. Likewise, in this embodiment, a second pneumatic line 156 is connected to shaft 120*. This line passes through hopper 16 to the outside. However, a branch or flexible hose line 158 from line 156 re-enters hopper 16 and is connected to air cylinder 146 for actuation thereof. Thus, air entering shaft 120 also passes through

lines

156 and 158 to energize cylinder 146, extending piston 150 thereof. This overcomes the force of spring 142 and pivots door 136 about its pivotal support 138 into closed position. Cylinder 146 is also provided with a vent line 160 communicating with the atmosphere.

It is evident that air entering shaft 120 is released through nozzle 108, and outlet 116 and, in addition, effects the closing of door 136 to permit pressurizing of the upper portion 126 of hopper 16 from outlet 116. The pressurizing of this portion of hopper 16 also assists in keeping door 136 in closed position.

Preferably, a second banch 162 is provided from line 156. This branch 162 passes through a conduit 164 extending through hopper 16, and is connected to a suitable pneumatic vibrator device 166 positioned against the outside of hopper 16 at the material arch line. Vibrat-or 166, it will be understood, assists nozzle 188 in maintaining free flow of the drain material M from hopper 16 into auger 10. As described in my aforementioned patent application, Serial No. 746,099, vibrator 166 can also be employed to vibrate auger 16 itself to thereby consolidate granular subsoils, or suiably rotated for that purpose. Emergency relief valve 168 is provid ed in hopper 16 to furnish means for manually releasing the pressure in section 126 in the event of a malfunction in the pneumatic system. Likewise, having one port in valve 110 connected to atmosphere permits venting of the entire system as desired.

It will be understood that when an auger cap is employed having the pneumatic latching system shown in FIG. 8, line 102 thereof is suitably connected to one of the pneumatic lines, preferably through a separate control valve (not shown) to one of the

pneumatic lines

112, 156 or 162, as is most convenient.

In the embodiment shown in FIG. 3, a plenum chamber 170 is employed. Chamber 170 is formed on the top of hopper 16 by plate 172, which extends across the top of hopper 16 between access opening 128 and flange 22. The plenum chamber 170 is thus defined by

plates

122 and 172 and the interior wall of hopper 16. In this embodiment, shaft 120 terminates at its lowermost end 121 in chamber 170. Thus, air emitting from shaft 120 pressurizes chamber 170. An outlet 174 from chamber 170 is connected through check valve 118 to line 112, which is pressurized from plenum 170 rather than directly from shaft 120, as in the embodiment of FIG. 1. In like manner, pneumatic line 156 is connected to and pressurized from plenum 170 rather than directly from shaft 120, as in the previously-described embodiment. Thus, the difference between the embodiments of FIGS. 1 and 3 resides in the pressurizing of the pneumatic system of FIG. 3 through a plenum chamber 1170 rather than directly from the pressure source as in FIG. 1. The use of a plenum chamber provides a greater degree of precise pressure control than is normally possible when the various branches of the pneumatic system are directly connected to the pressure source. However, in either case, the operation of the parts controlled is essentially the same.

Means are provided for loading hopper 16 with the porous drain material. Although hopper 16 can be filled at any point on its travel on leads 44 46, this is usually done when hopper 16 is in its lowest position after auger 10 is fully inserted in the ground. The drain material is elevated to hopper 16 by means of a travelling skip or hopper charger conveyor 176, comprising an elongated four-sided closure including a base plate 178, a pair of

side plates

188 and 182, a back plate 184 and an inclined top plate 186. An access 188 in the top of the skip provides an entry for loading thereof. The material exits from skip 176 through opening 190 therein opposite plate 184. Opening 190 is generally closed by a sliding plate member 192 until the start of the hopper charging operation. Hatch 192 is mounted for sliding travel in tracks 194 (only one shown) carried by the underface of base plate 178. Spring 196, secured at one end to plate 178 and at the other end to hatch 192, is operative to normally maintain hact 192 in closed position shown in full lines in FIG. 1.

To raise skip 176 to its elevated charging position shown in phantom in FIG. 1, there is provided a skip carriage 199 including a pair of

channel members

198 and 200 adapted for travel along leads 44 and 46, respectively, by carriage wheel 202 (see FIG. 2). As shown best in FIG. 1, the skip carriage 199 is disposed on

leads

44 and 46 beneath the auger carriage 32. Channel members 198 and 201) are cross-braced by plate 284-and retained in spaced horizontal relationship with channels 38 and 40 by spacers 286 (see FIG. 2).

To adapt it for travel, skip 176 is provided at each side thereof with

arms

208 and 210, secured together by a cross plate 212

adjacent leads

44 and 46. Plate 212 is, in turn, provided with a pair of spaced

eye elements

214 and 216. Eye 214 is disposed between the extending arms of a yoke member 218 fixed to channel 198, while eye 216 is disposed between the extending arms of a yoke member 220 fixed to channel 200. Pin 222 pivotally interconnects eye 214 and yoke 218, while pin 224 pivotally interconnects eye 216 and yoke 220.

In operation, a cable member 226 is secured in a suitable cab'le connector 228 carried by each

arm

208 and 210. Only one cable member 226 and connector 228 are shown for simplicity. The loaded skip 176 is then raised by means of cables 226 from a suitable power source such as a crane with the skip carriage 199 travelling vertically upwardly along leads 44 and 46 until the top of the skip carriage 199 contacts the bottom of the auger carriage 32. This limits the vertical travel of the skip carriage 199. However, continued raising of the skip by cables 226 effects pivotal movement of the skip 176 about pins 222 and 224 from its generally horizontal position shown in full lines in FIG. 1 to its inclined loading or discharging position shown in phantom in FIG. 1. Skip 176 continues to pivot about pins 222 and 224 until the extensions 238 and 232 on cam arms 234 and 236, respectively carried by skip

arms

208 and 210, contact their associated stop members 238 and 240 fixed to channel members 38 and 40, respectively.

With extensions 230 and 232 in contact with their respective stops 238 and 244), opening 190 in skip 176 is aligned with opening 128 in hopper 16. Hatch 192 contacts flange 132 and is then slid or cammed thereby against the action of spring 196 away from opening 190 to permit the material M to enter from skip 176 into hopper 16. Hatch 192 may also be actuated by means of a rope line from the ground, or, if desired, automatically by a pneumatically-actuated air cylinder (not shown). At the end of the hopper loading or charging operation, hatch 192 is permitted to return to its closed position as skip 176 is pivoted under its own weight to its horizontal position, and hence, with carriage 199, to ground until the next hopper loading operation. Stops 238 and 240 also serve to support carriage 199 in its unloading position, such that, if cables 226 are accidently released, skip 176 will not crash into hopper 16, thus avoiding damage to the equipment.

Means are also provided for controlling the maximum auger penetration rate and for simultaneously cleaning the auger flight 12 (see FIGS. 4 and 5) while ensuring proper alignment of the auger. To accomplish this, there is provided adjacent the entry of auger into the soil an arcuate auger guide 242 secured by spaced

extensions

244 and 246 to a support plate 248 carried by

leads

44 and 46, which are, in turn, suitably supported by a suitable support member 250, such as a crane catwalk. Disposed between

extensions

244 and 246 and pivotal'ly supported thereby on pin 252 is a tooth member 254. Tooth 254 is constructed and arranged to be disposed normally between successive convolutions of flight 12, as shown in full lines in FIG. 4. In this position, tooth 254 engages any soil clinging to the underface of flight 12 between successive turns thereof and removes it therefrom before entry of the flight into the soil. To facilitate disposal of the soil engaged by tooth 254, auger guide 242 is provided with openings (not shown) through which the soil may pass. Tooth 254 is adapted to be disposed as shown in full lines in FIG. 4 when auger It is penetrating at its maximum rate. When the rate of penetration of auger 10 is less than its maximum amount, tooth 254 will be pivoted upwardly about pin 252 to the position shown in dotted lines in FIG. 4. A shock absorber unit 256 bears against the bottom of tooth 254, minimizing the shock forces on the auger and its asosciated mechanisms dues to changes in anger penetration rate, and also ensuring continuous contact of the upper edge 258 of tooth 254 and the bottom surface of continuous flight 12.

It will be understood that if auger 10 suddenly encounters a stratum of soil having little strength and attempts to plunge or penetrate at a rate in excess of the desired rate, tooth 254 will be pivoted downwardly against the force of shock absorber 256 until stop 260, fixed to the bottom edges of

extensions

244 and 246, is encountered. Tooth 254, not being able to pivot further, will thus support auger 10, preventing the auger from plunging or penetrating in excess of its maximum rate. At least one air nozzle 262 is also provide to assist tooth 254 in cleaning flight 12. Air nozzle 262 may be suitably connected to the pneumatic system of hopper 16 previously described, or may be separately connected to the air pressure source.

It will be further evident that in the withdrawal operation of auger 10, tooth 254 merely pivots out of the way of the auger into its position shown in dotted lines in FIG. 4, offering no hindrance to the auger withdrawal.

Occasionally, when available head-room is limited and the hopper 16 cannot be raised to the full drain height as when the construction runs in the vicinity of an airport, it is necessary to realize the full drain length by means of coupling successive shorter lengths of auger togather rather than by a single auger. To provide for rapid coupling of successive lengths of auger 10a and 10b, novel coupling means is provided that is capable of transmitting high torque during the auger penetration operation, yet a coupling that can be quickly and easily applied and removed, since the coupling is constructed and arranged to transmit high torque without tightening.

To accomplish this, the ends of the central shafts of successive augers 10a and 10b to be joined are provided with mating teeth 266 which are rectangular as shown in FIG. 9. Likewise, the ends of the shafts to be joined 10 are oppositely threaded with shaft 101; provided with a right-hand thread 267, while shaft 10b has a left-hand thread 269. The coupling 268 for augers 10a and 10b is similarly threaded, having one set of right-hand threads 273 for application to shaft 10a and one set of left-hand threads 271 for application to shaft 1%.

In operation augers 10a and 10b are aligned in coupling 268 such that the teeth 266 of shafts 10a and 10b will ultimately mate, as shown in FIG. 9 for the triangular-shaped teeth. Coupling 268 is then suitably rotated as by a spanner wrench in the direction for application onto shafts 10a and 1% simultaneously. However, since this movement also effects relative movement of coupling 268 and shaft 10b because of the opposite threading thereof, the effect of rotating coupling 268 is to draw the ends of shafts 10a and 10]) toward each other into fully seated position in coupling 268 with the teeth 266 thereof in adjacent mating disposition as shown in FIG. 9 for the triangular-shaped teeth without relative rotation of the augers.

Continued rotation of the joined shafts 10a and 10b does not tend to tighten or loosen coupling 268 as is presently the case with coupled shafts, since the torque is transmitted directly through the joined shafts by means of mated teeth 266. Thus, coupling 268 can be quickly and easily removed when uncoupling shafts 10a and 1012. However, because of their mating teeth 266, shafts 10a and 10b can transmit the high torque required by the penetration of auger 10 into the soil formations.

It will be understood that shaft 10a may be the shaft having the left-hand thread, while shaft 1012 may be provided with the right-hand thread. The only requirement is that the shafts be oppositely threaded and coupling 268 be threaded as to accommodate each shaft 10a and 10b.

Where it is desired to put coupling 268 under tension to ensure stability when transmitting high torque, the triangular-shaped teeth of FIG. 9, or other suitably shaped teeth, are employed. This shape produces a vertical force component related to the force affected by the torque, hence putting a tensile stress into the coupling. This force component keeps the coupling from rotating if frictional forces are set up between the soil and the coupling during the angering operation.

FIG. 6 discloses another embodiment of the invention having particular suitability for the formation of earth of a column of materials, such as concrete piles. In this embodiment, wherein like numerals designate like parts to the previously described constructions, hopper 16 and anger 10 are rotated by means of shaft 26 through gear reducer 2-8. However, swivel 154 is connected to a preferably hollow shaft 270. Shaft 270 is preferably threaded and splined as shown, and is provided with a feed control collar 272. Shaft 278 passes through gear housing 274 where it is provided with a driving gear 276, which, in turn, is in selected driving engagement with variable-speed gear train 278 to rotate shaft 270 clockwise or counterclockwise, or gear 276 can be completely disengaged from train 278 to maintain shaft 270 stationary or to permit it to rotate with hopper 16 and anger 10. Any suitable means, such as manual levers, can be utilized for connecting gear 276 with the appropriate gears in train 278 to actuate shaft 270 as desired. Gear train 278 is driven from motor 30, which also drives gear reducer 28 but, in this embodiment, through a clutch member 29. By suitably actuating or de-actuating clutch 29, it is therefore possible to rotate shaft 270 while hopper 16 is rotating or stationary as desired.

As stated hereinabove, shaft 270 pases through gear housing 274 and is concentrically and rotatably mounted in shaft 26. Shaft 270 also is rotatably disposed concentrically through suitable bushings in

plates

122 and 172 and then hopper 16, passing through plenum 170.

1 1 The section of shaft 270 located in plenum 170, however, is provided with an outlet 280 to admit air therein from the air pressure source into the plenum chamber 170. The bushings in

plates

122 and 172 and bearing 282 are suitably sealed to prevent excessive loss of air pressure from plenum 178.

Shaft 270, suitably supported in bearing 282, passes through plenum 178 and extends preferably at least the entire length of hopper 16. Shaft 270 may be vertically advanced through auger 18 and hopper 16 by means of feed collar 272. When it is desired to advance shaft 276, collar 272 is suitably rotated for threaded travel along the splined section 271 of shaft 270.

It will be understood that spline 271 extends through bearing 282 for proper vertical movement of shaft 270.

In this embodiment, hopper 16 preferably has its lowermost terminal section 284, formed in the shape of a cylinder, of a diameter corresponding to the inside diameter of shaft 11.

Shaft 270 extends through hopper 16 and section 284 thereof and has at least the portion thereof in hopper 16 provided with a continuous flight 286. As shown, the portion of flight 286 in section 284 is preferably of constant diameter and gradually widens from section 284 upwardly in hopper 16 (see FIG. 6).

In operation, hopper 16 is loaded as heretofore from skip 176. However, in this instance, pre-mixed concrete is loaded into hopper 16. If desired, the concrete ingredients can be deposited in hopper 16 and shaft 270 can be suitably driven by gear train 278 in a direction opposite to the arrow, FIG. 6, to properly mix the concrete. Also, shaft 270 can be rotated in the mixing direction when pro-mixed concrete is used to complete the mixing thereof and eliminate a segregation of aggregate that may have occurred in the loading operation.

At the end of the loading operation, plenum 170 is presurized from shaft 270. This, in turn, effects closing of door 136 'by actuation of cylinder 14-6 and opening the cap by actuating cylinder 90 from line 288 communicating with plenum 170. It will be understood that in this embodiment it is not necessary to pressurize the top section of hopper 16 since there is no danger of blow-back; hence, door cylinder 146 and door 136 may be eliminated, if desired. In like manner, any external air-actuated accessories, such as vibrator 166, are actgated from line 290 also communicating with plenum 1 0.

Auger is rotated by motor 30 to cut into the soil to the desired depth 'as heretofore described. In the construction of piles, this depth usually extends until a suitable bearing stratum or rock is encountered upon which the pile can rest. These are known as point-bearing piles. However, piles can also be constructed in relatively stable soils with this apparatus by simply cutting into the soil to the depth calculated to provide the proper amount of support for the pile load by soil friction. When the desired depth of the auger is reached, the auger is rotated one or more times to cut a soil core from the natural formation and the auger is then withdrawn to form a cavity in the soil as heretofore, removing the driving cap 58 in the process.

To fill the soil cavity and thus form'the pile, shaft 270 is rotated in the direction of the arrow, FIG. 6. The concrete in the hopper is engaged by the rotating flight 286 and travelled downwardly thereby in the manner of a screw feed device toward and into auger 10.

Shaft 270 and its flight 286 preferably. extend the entire length of auger 10, ensuring a positive feed of concrete all the way into the soil cavity. However, shaft 270 and its flight 286 can terminate at the connection of auger 10 and hopper 16 and the concrete allowed to flow by gravity through auger 10. Alterantively, shaft 270 and its flight 286 can terminate at some intermediate point in auger 10 with the concrete completing its travel through Car auger 10 under the force of gravity. If hopper 16 is pressurized, the air pressure assists in moving the concrete. In any event, shaft 270 and flight 286 ensure a continuous, positive feed of concrete from hopper 16 into auger It will be evident that in this arrangement, concrete having the conventional size aggregate and ingredients can be used successfully without component segregation, thereby ensuring homogeneity in the formed pile with predictable support capacity. Further, since the concrete. is positively fed to the auger, a low slump concrete can be used, giving higher strength, and no big voids in the pile column can occur, and through vibration the desired density can be achieved. The term big voids denotes disjunction in the pile.

In the present embodiment, it will be evident that shaft 270 need not be hollow to effect proper concrete feed. However, when shaft 270 is of the preferred hollow type, a blow-count probe 291 can be inserted through shaft 270 into the soil or rock in advance of any concrete deposit. By means of probe 291, the resistance of the soil or rock can be determined for each pile by counting the number of blows on probe 291, using a known force to drive the probe. Thus, the true bearing capacity of the soil can be readily and accurately calculated prior to forming the pile. This was impossible heretofore in cast-inplace piles, since the driving of the mandrel for such piles so altered the soil characteristics that true bearing values could not be obtained and there was no suitable way to insert a probe.

In like manner, hollow shaft 270 can accommodate a suitable sample spoon or rock core sampler 292 for obtaining true and accurate samples of the soil or rock upon which the pile is to be placed.

Another advantage realized by means of the invention is the ability to consolidate and densify the pile material as it is being formed. In this case, a vibrator 294 is inserted either through hollow shaft 270 into the freshly deposited concrete or connected directly to the lower end of shaft 270. Vibrator 294, which may, if desired, be actuated from plenum 170, is operative to vibrate the deposited concrete as it is deposited or immediately thereafter, eliminating Big voids therein and thus densifying the pile structure to form a stronger pile.

Occasionally, it is desired to provide the pile with a full seat in the rock rather than merely resting the point on the surface thereof. It will be obvious that seating the pile greatly increases its load-carrying capacity. In the present invention, if such is desired, shaft 270 is dimensioned to extend the entire length of auger 10 and is provided at its lowermost terminal end with a drill bit such as bit 296 of FIG. 12. Alternatively, shaft 270 can accommodate an interior concentric shaft (not shown) provided with bit 296. Bit 296 is rotated in advance of auger 10 to drill the desired seat in the rock.

A cap similar to that shown in FIGS. 7 and 8 is used preferably when soil and rock samples are required and when vibrators or probes are used. However, when shaft 270 is provided with a bit 296, the upper section of shaft 270 is threaded as at 271, which meshes with feed collar 272. To prepare the auger 10 for insertion into the soil, bit 296, preferably of a diameter approximately equal to the outside diameter of shaft 11 when bit 296 functions as a cap also, is drawn into place by taking up on feed collar 272.

Feed collar 272, which can be rotated either manually or by remote means (not shown), bears against hub 275 of gear 276 when shaft 270 is drawn up to the proper position for its cap or bit 296 to bear against the bottom 56 of shaft 11. When the auger descent into the subsoil is completed, the feed control collar 272 is backed-off or travelled upwardly away from bearing on hub 275 of gear 276; thus, as the carriage 32 is withdrawn with the hopper 16 and auger 10 attached thereto, shaft 270 does not move until suitable contact is made between hub 275 and the feed control collar 272, at which point shaft 270, whose thread 279 is meshed with the feed control collar 272, is pulled upward with the system. The lead distance of hub 275 to produce the contact with the feed collar 272 provides an equivalent space between the bit 296 attached to the lower extremity of shaft 270 and the bottom 56 of auger shaft 11. This lead space furnishes the required space for the backfill material M to pass from the hollow 14 of shaft 11 into the cavity C in the soil formed'by auger 10.

To permit vertical movement of the shaft 270, when gear train 274 is part of the system, shaft 270 is also provided with a spline 277 with meshes with an equivalent spline internal to hub 275 of gear 276. Bearing 282, used to maintain the true alignment of shaft 270, also has its inner race suitably splined. The plate 122 through which shaft 270 passes would have a suitable bushing or bearing provided for shaft 270 alignment as does plate 172. If the plenum is to be pressurized through nozzle 280, the points where shaft 270 passes through

plates

122 and 172 must be made sufliciently air-tight to prevent excessive loss of pressure. In addition, nozzle 280 must be so positioned during the time of pressure build-up that it is within the limits of the plenum, or else additional openings may be provided in shaft 270 such that at least one pressure injection point, such as nozzle 280, is always available to supply the plenum.

During the drilling operation, feed control collar 272 is suitably backed-off through gear 276 of gear train 274, and shaft 270 with drill bit 296 attached to its lower end is rotated. Pressure applied to the drill may either be limited to the weight of shaft 270 or, if this is insufiicient to produce proper drilling pressure, then a weight annular to shaft 270 and resting on feed control collar 272 may be added as needed. This same type of weight may be used to drive shaft 270 when used as a probe. In this fashion the drilling pressure maintained at the drill may be held constant for most eflicient results.

In instances where it may be desired to have internal auger 286 in a specific relative position during that portion of the operation when material is being mixed or fed, a portion of the flights of auger 286 can be suitably shaped to fit into hollow 14 of auger to permit the required drill lead movement and at the same time be properly positioned by contact with the lower taper 18 of hopper 16 to permit the lead. If desired, an upper stop may also be provided on shaft 270, such as collar 283, which contacts bearing 282 when shaft 270 is in its uppermost position.

It will be understood that a drill bit 296 can also be employed with the embodiments of the invention shown in FIGS. 1 and 3. Such drill device is utilized when the auger 10 encounters an obstruction, such as a boulder or strata of auger-resistant material like a course gravel lens. In such instance, bit 296 can be inserted through shaft 120, or a shaft similar in construction and operation to shaft 270 can be mounted axially within hopper 16 and auger 10 and provided with a bit 296 to serve as the cap for auger shaft 11 for rotation with anger 10, and when needed, rotatable in advance of the anger as previously described for penetration of obstructions.

It will be understood that when shaft 270 is provided with drill bit 296 serving as a cap also, there is no requirement that shaft 270 be hollow.

Likewise, it will be understood that, throughout the specification, while there is disclosed a pneumatic pressure system for actuating the several associated devices, other fluid pressure means can be employed by those persons skilled in the art.

I have also found that a suitably densified .pile can be obtained by means of the mechanism shown in FIG. 6 without the necessity of utilizing vibrator means. It will be understood that flight 286 acts as a screw-feed device forcefully feeding concrete from hopper 16 into auger shaft 11. To obtain a densifying effect from the screw-feed action of flight 286, the auger .10 is extracted from the soil, forming the soil cavity at a given rate of speed. However, flight 286 is rotated at a speed to feed concrete linearly into the cavity at a second rate of speed slightly faster than the rate of withdrawal of anger 10, thus feeding a slight excess of concrete into the cavity. This excess feed effects a densifying of the formed pile by eliminating big voids therein. Flight 286 agitates the concrete for better density.

A like effect can be realized by weighting the end of shaft 270 to apply added weight to the concrete in the soil cavity. This added weight is also desirable when the mechanism for drilling through obstructions is utilized as described hereinabove. This added weight brings greater pressure to bear on bit 296, facilitating the drilling operation.

It will be further understod that flight 286 also operates to agitate or mix the concrete even when rotating in the mixing direcion of the arrow, FIG. 6, to prevent segregation of the concrete ingredients.

Thus, there is disclosed novel methods and mechanisms for forming columns of material in soil or earth formations, wherein the columns are formed with a minimum of displacement, smear, re-molding, and disturbance of such soil formations, means for penetrating such columns through obstructions, as well as means for temporarily or permanently inserting equipment and devices into such columns simultaneously with the construction of such columns.

What I claim is:

1. Apparatus for forming a column of material in soil comprising an auger having a hollow shaft and cutting means for penetrating said hollow shaft into said soil, a hopper for admitting a supply of columnar material into said hollow shaft, means mounting said hopper and auger for travel toward and away from said soil, means connecting the interior of said hopper and the interior of said hollow shaft to permit the passage of columnar material from said hopper to said hollow shaft, means for rotating said auger for penetrating said auger into said soil to the desired depth, means for travelling said auger to withdraw said auger from said soil to form a cavity in said soil, a rotatable flighted shaft mounted within said hollow shaft, means for rotating said flighted shaft within said hollow shaft to feed said columnar material through said hollow shaft to form said column of material as said apparatus is withdrawn from said soil.

2. Apparatus for forming a column of material in soil comprising an auger having a hollow shaft and cutting means for penetrating said hollow shaft into said soil, a hopper for admitting a supply of columnar material into said hollow shaft, means mounting said hopper and anger for travel toward and away from said soil, means connecting the interior of said hopper and the interior of said hollow shaft to permit the passage of columnar material from said hopper to said hollow shaft, means for rotating said hopper and auger conjointly for penetrating said hollow shaft auger into said soil to the desired depth, means for travelling said hopper and auger to withdraw said auger from said soil to form a cavity in said soil, a movable means located at the penetrating end of said auger to prevent the intrusion of soil into said hollow shaft, and means to control said movable means to permit passage of columnar material from said hollow shaft into said cavity as the apparatus is withdrawn from said soil.

3. The invention as defined in claim 1, whereina movable means is located at the penetrating end of said hollow shaft auger to prevent the intrusion of soil into said hollow shaft.

4. The invention as defined in claim 2, wherein said movable means located at the penetrating end of said auger to prevent the intrusion of soil into said hollow shaft is connected to a control means which has an actuating system extending to a point remote from said penetrating end.

5. Apparatus for forming a sand column in soil comprising an auger having a hollow shaft and an outer cutting flight for segmentally supporting a soil core, a hopper for admitting a supply of sand, means communicating the interior of said hopper with the interior of said hollow auger shaft, means for rotating said auger for penetrating said auger into said soil to the desired depth, means for pulling said auger from said soil to form a cavity therein, means to prevent arching of sand at the point of communication between said hopper and said auger hollow shaft, a cap means on the penetrating end of said auger hollow shaft, and means for displacing said cap means for admitting sand from said auger hollow shaft into said cavity to form said sand column.

6. Apparatus for forming a cast-in-place pile in soil comprising a hollow shaft auger and an outer cutting flight for segmentally supporting a soil core, a hopper for admitting a supply of pile material, means mounting said hopper on one end of said auger, means communicating the interior of said hopper with the interior of said hollow auger shaft, means for rotating said auger for penetrating said soil to the desired depth, means for pulling said hollow shaft auger from said soil to form a cavity therein, a second shaft having an outer flight mounted within said first auger hollow shaft, means rotatably mounting said second shaft axially in said hollow shaft auger and hopper, means for rotating said second shaft to feed pile material through said hollow auger shaft, a cap means on the other end of said auger shaft to prevent intrusion of soil into said hollow shaft, and means for displacing said cap means to admit pile material from said hollow shaft into said cavity to form said concrete pile.

7. The invention as defined in claim 6, wherein said second shaft is provided with a hollow axial opening for accommodating an auxiliary construction element.

8. Apparatus for controlling the penetration rate of apparatus for forming a column of material in soil by means of a cavity forming rotatable auger with external flight cutting means, comprising a tooth mounted adjacent to said rotatable auger, means mounting said tooth for pivotal movement in the direction of auger movement, said tooth mounting means positioning said tooth within and in engagement with said external flight cutting means, a stop means for limiting the pivotal travel of said tooth when said auger flight movement urges the tooth to pivot toward said soil thereby controlling the linear travel of said auger toward said soil to a rate related to the speed of auger rotation and selected configuration of said external flight cutting means engaged by said tooth.

9. Apparatus for conveying material to the uppermost end of a column forming hollow shaft auger apparatus comprising carriage means for pivotally supporting a container holding said columnar material, means for travelling said carriage and container to a measured point along said hollow shaft auger apparatus, stop means provided on said hollow shaft auger apparatus limiting further linear movement of said carriage toward the uppermost end of said auger apparatus, pulling means to rotate said container in said pivotally supporting means, guide means on said container for engaging cooperating guide means on said hollow shaft auger apparatus whereby said container is positively controlled in its rotation toward the uppermost end of said auger apparatus to enable the material in said container to be fed into said hollow shaft auger apparatus.

10. Apparatus for forming a sand column in soil comprising an auger having a hollow shaft and an outer cutting flight for segmentally supporting a soil core, a hopper for admitting a supply of sand, means communicating the interior of said hopper with the interior of said hollow auger shaft, means for rotating said auger for penetrating said auger into said soil to the desired depth, means for pulling said auger from said soil to form a cavity therein, means to prevent arching of sand at the point of communication between said hopper and said auger hollow shaft, a cap means on the penetrating end of said auger hollow shaft, and means for displacing said cap means for admitting sand from said auger hollow shaft into said cavity to form said sand column, wherein the sand partially fills said hopper, said hopper includes an outlet from a pressure system to control a closure element for said hopper, a second outlet from said pressure system located within the hopper to pressurize said hopper after closure, said pressure system also operating the arch preventing means to maintain the continuous flow of sand.

11. The invention defined in claim 6, including means for rotating said second shaft having an outer flight independently of said hollow shaft auger and hopper.

12. The invention as defined in claim 6, including means for rotating said second shaft in a direction opposite to its feeding direction for mixing concrete in said hopper.

13. A method of forming columns of material in soil by means of an anger apparatus containing a supp-1y of column forming materials and having a hollow shaft with a cutting flight or flights, and hollow shaft having a conveyor means extending longitudinally of and within said hollow shaft, comprising helical cutting into said soil with said hollow shaft auger, withdrawing said auger from said soil such that a cavity is formed in said soil, conveying said contained material into said cavity in timed relationship with the withdrawal of said auger to form said column of material.

14. The method of claim 13 wherein the conveyor means is a flighted shaft.

References Cited by the Examiner UNITED STATES PATENTS 1,356,125 10/ 1920 Chattstrom 84 1,817,240 8/1931 CuthbeItSOn 2.. 30253 2,048,710 7/ 1936 Ranney 61-63 2,109,344 2/1938 Selger 285330 2,195,492 4/1940 McDonald 285330 2,729,067 1/1956 Patterson 6153.58 2,822,671 2/1958 Dentz et al. 6153.66 X 2,920,455 1/1960 Ryser et al. 6-1-53.64 2,952,131 9/ 1960 Lyroudias 61-63 3,096,622 7/1963 Landau 6110 3,115,074 12/1963 Smith 9446 FOREIGN PATENTS 582,692 9/ 1963 Canada.

CHARLES E. OCONNELL, Primary Examiner.

JACOB SHAPIRO, Examiner,

Claims

13. A METHOD OF FORMING COLUMNS OF MATERIAL IN SOIL BY MEANS OF AN AUGER APPARATUS CONTAINING A SUPPLY OF COLUMN FORMING MATERIALS AND HAVING A HOLLOW SHAFT WITH A CUTTING FLIGHT OR FLIGHTS, AND HOLLOW SHAFT HAVING A CONVEYOR MEANS EXTENDING LONGITUDINALLY OF AND WITHIN SAID HOLLOW SHAFT, COMPRISING HELICAL CUTTING INTO SAID SOIL WITH SAID HOLLOW SHAFT AUGER, WITHDRAWING SAID AUGER FROM SAID SOIL SUCH THAT A CAVITY IS FORMED IN SAID SOIL, CONVEYING SAID CONTAINED MATERIAL INTO SAID CAVITY IN TIMED RELATIONSHIP WITH THE WITHDRAWAL OF SAID AUGER TO FORM SAID COLUMN OF MATERIAL.