US3200599A - Method for forming piles in situ - Google Patents

Description

Aug. 17, 1965 1 J. PHAREs ETAL 3,200,599

METHOD FOR FORMING PILES IN SITU 'MMMW HTTOFNEK Aug. 17, 1965 L. J. PHARES ETAL 3,200,599

METHOD FOR FORMING PILES IN SITU Filed Dec. 23, 1960 ll Sheets-Sheet 2 Aug. 17, 1965 l.. J. PHAREs ETAL METHOD FOR FORMING PILES IN SITU 11 Sheets-Sheet 4 Filed Dec. 25. 1960 Aug 17, 1955 L. .1. PHARES ETAL 3,200,599

METHOD FOR FORMING PILES IN SITU Filed Dec. 25, 1960 ll sheets-.sheet e #1293 rd, I I I I II/ 20] I I I I I I I I I I 107 706 I 105 I I I I I g I I I/ 19@ I M s 74 775 IN VEN TORS.

L /NDsEV J PHAQES. H'HQoLoM/Ifc CALL. BY Plc/#119D ICS/vanaf.

ATTORNEKS.

ug- 17, 1965 L. J. PHARx-:s ETAL 3,200,599

METHOD FOR FORMING PILES IN SITU Filed Deo. 25, 1960 11 Sheets-Sheet 7 IN VEN TORS. LINDSEY JPHAQES. HAQOLDMZWC/QLL BY P/cHA/PDK-S/vo m iQ/V557- WpmvNH/q/(E.

Aug. 17, 1965 1 J. PHARl-:s ETAL 3,200,599

METHOD FOR FORMING PILES IN SITU Filed Deo. 25. 1960 11 Sheets-Sheet 8 IN V EN TORS. L /NDSEVJ PHA PES. Hapol. DM/fcC/ML. B Y P/cH/qpo/(S/vow E'p/vs-WPANNHAKE.

Aug. 17, 1965 1. PHAREs ETAL 3,200,599

METHOD FOR FORMING PILES IN SITU Filed Dec. 23, 1960 u Sheets-Sheet 9 HQPOLDMMCCHL B YP/cH/vpo if.' SNOW a INVENTOR EQ/VSTWDAN/VHAKE.

L @44a/MM@ Aug. 17, 1965 1 J. PHARl-:s ETAL METHOD FOR FORMING PILES IN SITU ll Sheets-Sheet 10 F'iled Deo. 23. 1960 INVENTORS.

L/NDSEVJPHAPES.

' HAPOLDMMCCQLL. BY P/CHAQDKS/VOIM EPA/STWPANNHKE.

TPVEK United States Patent O 3,2005@ METHOD FUR FRMING PILES EN SH'U Lindsey J. Phares, Smoke Rise, Butler, and Harold M.

McCall, Fair Lawn, NJ., Richard K. Snow, St. Petersburg, Fla., and Ernst W. Spannhake, Smoke Rise, Butler, NJ., assignors to Raymond International Inc., New

York, N .Y., a corporation of New Jersey Filed Dec. Z3, 1960, Ser. No. '77,973 4 Claims. (Cl. 6-53.64)

This invention relates to methods and apparatus for placing caissons or piles of the shell-less type in the earth by hollow stern auger drills by pumping a cementitious material, vsuch as grout, through such stem into a cavity formed beneath the auger as it is Withdrawn, together with the earth in its ilights, from a hole in the earth which has been drilled by it. The invention more particularly relates to novel methods and apparatus for improving the quality of such piles, including the shape and strength thereof, by controlling and adjusting in a novel manner the pressures and volume ofthe cementitious material placed in such cavity during auger withdrawal.

Methods and apparatus of this general character in the prior art have failed to provide any suitable or accurate control and adjustment of pressures of the cementitious material in such a cavity beneath the auger.

Also such prior art methods and apparatus have failed to make the most economical use of such cementitious material by so failing to control and adjust the pressures of the material in theicavity beneath the auger.

Further, such prior art methods and apparatus have been relatively kslow in forming such piles.

Also, the prior art has failed to provide adequate methods and apparatus for forming piles of the above character and. concurrently placing therein reinforcing rods or bars.

One kof the objects of the present invention is to overcome the above difficulties or to reduce same to insignilicance.

Another object is to provide novel methods and apparatus for controlling and recording certain factors, such as the pressure of the cementitious material near the auger tip during the injection thereof thereby to demonstrate the quality of shell-less piles of'this type.

A further object in one form of the invention is to sense and indicate that variable factor occurring during the formation of such piles which, by adjusting other factors such as drill rise rate and grout inflow rate, can be most advantageously controlled and adjusted to obtain high quality piles, namely, the pressure of the grout or other cementitious material at or near the lower end of the auger drill during drill withdrawal and injection of the grout, such pressure being controlled to follow preselected values during such drill withdrawal.

A furtherobject is to provide novel methods and apparatus for forming a shell-less type pile of cementitious material which is capable of developing skin friction at least equal to that of a driven pile in certain types of earth, for example, wherein there occurs lateral protrusions of such material.

Another object is to provide novel methods and apparatus for avoiding in the cementitious material near the drill tip during drill Withdrawal any substantial pressure variations from selected norm values.

Another object is to provide novel methods and apparatus for controlling the pressure of the cementitious pile-forming material as measured at the upper region of the cavity vacated by the rising auger drill, such pressure control providing a positive and accurate method and means for preventing a cave-in of the earth surrounding such cavity while making most economical use of such material.

n n p ICC A further object is to provide novel methods and apparatus for attaining and maintaining accurate control over the pressure of the cementitious mixture during the injection of the latter substance into the cavity beneath the auger during its Withdrawal from the hole which has been drilled by it.

Another object is to provide novel methods and appaL ratus for controlling the speed of drill withdrawal.

A further object is to provide novel methods and apparatus for controlling the pressure conditions 0f the cementitious material which is injected into the cavity beneath the drill by correlating in a novel manner the volumetric inflow rate of such material into the cavity and the rate of withdrawal of the drill or auger to insure a selected pressure gradient in the upper region of such material as the drill is withdrawn, and also to insure that the pressure of the cementitious material at the region of the lower end of the drill comprises during drill withdrawal a selected function of'the depth of such lower drill end during withdrawal.

A further object is to provide novel methods and apparatus for controlling the cementitious material pressure conditions in the cavity by integrating and correlating during drill withdrawal the total cementitious mixture iiow volume) with the total volume of the cavity.

A further object is to provide novel methods and apparatus for the control of the withdrawal of an auger drill from a hole drilled in the earth by it, such control being eiected by servo means under the inuence of the pressure of the substance injected into the cavity formed by the withdrawal .of the auger from the hole.

A further object is to provide novel methods and apparatus for controlling the hoisting of the auger out of a hole in the earth drilled by it by sensing the pressure of the cementitious mixture in the hole and controlling and adjusting the hoisting in response to such sensed factor.

Another object is to provide novel methods and apparatus to insure adequate filling with cementitious material of the cavity beneath an auger drill during its withdrawal from a hole in the earth drilled by it by correlating in a novel manner the number of turns of a pump which forces such material into the cavity with the linear extent of drill withdrawal from the bottom of the hole.

A further object is to provide novel methods and apparatus to establish proper depth and load-carrying capacities of piles by sinking an auger drill to a depth Where the torque required to drive same is at a value equal to the torque required to sink the auger for ,previous piles which have met satisfactory load tests.

A further object is to provide novel valve apparatus for the lower end of suchv auger drill for controlling the ow of a drill medium, such as water or drill mud, and also for the control of the ow of a pile-forming material such as grout.

A further object is to provide a novel auger drill having means for keeping the drilling medium, such as Water or mud, used in the drilling of the bore separate from the cementitious mixture or grout employed in forming the pile.

A further object is tofprovide a novel valve structure employed at the lower extremity of a hollow stem auger which enables an operator at his discretion to stop and start a rlow of a pile-forming substance from such lower extremity. n

A further object is to provide a novel valve for the lower extremity of a hollow stem earth auger which valve is held shut by the downcrowding force applied to the auger stem during drilling into the earth with the auger, such valve being responsive to gravity and the pressure of a pile-forming material, such as grout, Within the hollow stem of the auger at the start of the withdrawal or hoisting operation of the auger, the pile-forming material being directed toward the valve via the passage in such hollow stem which thus aids in pushing such valve open.

A further object is to provide a novel valve device for the lower extremity of an auger type earthdrill wherein one of the movable valve elements mount a cutter head for the drill, for example, a pilot bit, drilling torque being applied to such cutter head by novel mechanical means which serve the double purpose of transmitting such torque and holding in aligment the movable part of the valve.

The invention, in one aspect thereof, comprises a method for forming piles in the earth and consists in `the steps of sinking an auger with a hollow stem into the earth to a selected depth, extracting the auger while sinking) and thereafter exerting a force in an upward direction on the drill while concurrently forcing yunder pressure into the cavity created beneath the drill, and via said hollow stern, a cernentitious mixture of pile-forming material, the force acting on the drill being adequate to raise the drill out of the earth together with the earth in its flights vthereby to withdraw same from the hole. During such drill withdrawal, there is provided a primary series of signalsindicating the-injection via such stem into the cavity of a corresponding series of increments of selected volume of such cementitious mixture,and also there is provided a secondary series of signals indicating the occurrence of a corresponding series of successive selected linear increments of drill rise,` each producing pumping grout through the passage in the stem into the cavity below the auger to ll such cavity, and sensing the pressure of the grout at or near the lower end of the auger and regulating the `rate of auger extraction in response to such sensed pressureY to insure that such cavity filling occurs, such pumping of the grout into the cavity being at a substantially constant volumetric flow rate.

The invention, in another aspect thereof, comprises a method for forming piles in the earth and consists in the steps of drilling a hole in the earth by sinking to a desired depth an auger type drill by turning same, the drill being provided with a hollow tubular stem and spiral iiights. After the drill has been sunk to the desired depth, it is progressively withdrawn from the hole, together with the earth in its ights by applying a lifting force thereto adequate for this purpose and thereby forming beneath the drill a cavity adapted'to receive a pile-forming substance, such as grout. The volume of the cavity vprogressively increases as the driil is Withdrawn and while it is so increasing the cavity is filled completely during drill withdrawal by forcingtherein with the aid of a pump and via the hollow stem the aforementioned pileforming substance. The rate of drill withdrawal and the volumetric rate of inflow of such pile-forming substance into the cavity are controlled to produce a changing pressure of the pile-forming substance as measured near the lower end of the drill, which changing pressure is a function of the changing level of the lower end of the drill as it is lifted out of the hole, and such controlling includes adjusting one or both of such rates to change the an added increment of volume of theV cavityv selected substantially to yaccommodate such volumetric increments of the cementitious mixture injected into the cavity. The raising of theY drill and theV injection ofthe mixture are Vcontrolled so that for each such primary signal there occurs substantially concurrently one of the secondary signals.

pressure of the cementitious mixture to a desired value in response to such pressure departing from desired norm Values at selected levels of such lower drill end during its withdrawal. v

The invention in a further. aspect thereof comprises the method for forming piles in theA earth which consists in drilling a hole in the earth by sinking an auger type drill therein by rotating same and after the drill has been sunk to a desired depth, exerting a lifting force on the drill adequate to lift it outvof the earth thereby to form a cavity beneath the drill while concurrently forcing a The invention in a still further aspect thereof comprisesk the method for forming piles in the earth which consists in turningr an auger type Vof drill to sink same into and thereby form a hole of a desiredV depth inthe earth, the drill having a hollow stem with avalve outlet at the lower end thereof (the 'valve being closed 'duringV drill The above and further objects and novel features of the present invention will 'more clearly appear from the description set forth below when thevsame is read in connection with Vthe accompanying drawings which are submitted herewith for purposes of illustration only and which do not define the limits of the invention, reference for this latter purpose being had to the appended claims.

lIn the drawings:

FIG. l is a side elevationvof an apparatus/comprising a truck-borne drill rig embodying one form of thepresent invention; f

FIG. 2 is a schematic representationV of Vthe apparatus shown in FIG l but with the drill, namely, a hollow stem auger, penetrating into the earth, there being also shown apparatus for directing a cementitious mixture, such as grout, into the hollow stem of the auger;

FIG. 3 is a schematic representation, partly in section and with parts broken away, showing a crown assembly of the auger drill employed in FIGS. 1 and-2 and embracing the mount for the auger drill at its upper extremity, such crown assembly being adapted for vertical movement as guided by a mast of the drilling rig; Y

FIG. V4 is a schematic representation of a portion of means employed in the present'invention for sensing the pressure Vof the cementitious material near the drill tip and comparing it with a norm;

FIG. 5' is aschematic representation of the manner in which a hoisting cable of the present invention is associated with the crown assembly for raisingand lowering the auger drill thereof, said arrangement being referred to as a reavingl diagram for the hoisting apparatus;

FIG. 6 is a diagram of the several control means and indicators available to the operator of the apparatus ernbodying the present invention in the form of FIGS. l and 2; FIG. 7 is a schematic representation of apparatus for sensingthe pressure of the rcemetitious mixture, such as grout, at the lower extremity yof the drill and for comparing such sensed pressure with a selected 'norm pressure a portion of this apparatus being shown in FIG. 4;

v FIG. 7a is a graphical comparison of a norm grout pressure `gradient and grout pressuresensed at or near the lower drill end during drill withdrawal;

FIG. 8 is a vertical sectional view, partly in section and with parts broken' away, of a portion of a, differential diaphragm pressure sensitive'device which is employed near.r the ylower extremity or tip -of the drill as shown in FIG. 7;

FIGK9 is a front `elevation of the parts shown in FIG. 8 but also showing schematicallyacheck valve connected thereto; l FIG.`V l0 is a vertical sectional-viewpartly in section and with parts broken away,KVI of such differential diaphragm device, a part of which is shown Vin FIG.V 8 and which embodies a valving device for aiding in sensing the pressure as aforementioned;

FIG. 11 is a front elevation of the parts shown in FIG.

FIG. 12 is a schematic representation of one form of apparatus for integrating and comparing factors representing the total volume of the cementitious mixture pumped into the cavity beneath the drill and the total volume of such cavity as the drill is withdrawn from the hole which it has drilled in the earth;

FIG. 13 is a side elevation, partly in section and with parts broken away, of one form of the lower extremity of the hollow stern auger drill employed in the present invention and showing a valve in such stem for controlling the flow of the cementitiousmixture, such as grout, the-lower extremity of the auger being shown at the bottom of a hole which it has drilled, the valve being shown in its closed condition, there being a down pressure exerted upon the lower tip or end of the auger as during the hole drilling process;

FIG. 14 is a view of the parts shown in FIG. 13 but with the auger drill being withdrawn from the hole and wherein the down pressure on its lower extremity is relieved and by virtue Iof the weight of an axially movable lower valve portion the aforementioned valve for the grout or cementitious mixture is open allowing it to flow through the valve and into the cavity beneath the drill during withdrawal;

FIG. 15 is a sectional view taken substantially along lines 15-15 of FIG. 14;

FIG. 16 is a side elevation, partly in section and with parts broken away, of the lower extremity of a drill or drill stem employed in the present invention and showing another form of valve construction embracing valves for controlling the flow of both the cementitious mixture and the drilling medium, e.g. water;

FIG. 17 is a vertical sectional view, partly in section and with parts broken away, of an an upper portion of the auger drill which portion includes a water swivel assembly and comprising a showing of two concentric tubular portions of the stem of the auger and means for directing water into one of such passages by means of a relatively stationary collar which is in communication with a rotating portion of the drill stem;

FIG. 18 is a sectional view taken substantially along line 12B- 18 of FIG. 17;

FIG. 19 is a side view, partly in section and with parts broken away, of a modification of the auger construction shown in FIG. 13 and illustrating means for placing one or more reinforcing bars;

FIG. 20 is an end elevation of the parts shown in FIG. 19;

FIG. 21 is a sectional view taken substantially along line 21--21 of FIG. 19; and

FIGS. 22, 23 and 24 illustrate a modification of FIGS. 19, 20 and 21.

Referring to the drawings in greater detail, with particular reference to FIGS; 1-4, the apparatus embodying the form of the invention therein shown is broadly designated at 20 and comprises a mobile drill rig including an auger type earth boring drillv 21 which is suspended rotatably from its crown by means of a crown assembly 22 which is mounted for vertical movement with the aid of suitable rails of a mast 23, such rails, for example, being shown at 24 and 2S.

The mast Z3 is mounted for pivotal movement (between vertical and horizontal positions) about a shaft 26, such shaft being mounted upon a Icarrier truck 27 by means of two pairs of arms 2S, 29 and 30, 31, the latter pair not being shown in FIG. 1.

The pairs of arms 2S, 29and 30, 31 in turn are mounted upon a shiftable deck 32 which in turn is mounted upon the back 33 of the track 27.

,Normally the deck 32 mounting the arms 28, 219 and 30, 31 is held rigidly in place for drilling, but such deck 6 can be adjusted in position and shifted fore and aft of the truck along a horizontal center line through, for example, a selected distance, such as two or three feet, by means of a suitable slidable mounting (not shown). This sliding movement is controlled by a pair of hydraulic slide cylinders 34, only one of which is shown in FIG. 1.

y The shiftable deck 32 also can be angularly shifted about a vertical axis through a selected angular distance, for example, i40 with respect to its norm centered position, by means of a pair of hydraulic cylinders 35, again only one of which is shown in FIG. 1.

The mast 23 is provided with cylindrical auger guides 36 and 37. The latter by suitable reaving means (not shown) -is positioned midway between the auger crown and the mast bottom.

Further, the mast 23 can be raised and lowered by means of a pair of hydraulic mast raising cylinders 38, one of which is on each side of the mast. Each of such mast raising cylinders is operatively associated with the mast, as shown in FIG. 1, the righthand extremity of the cylinder thereof being secured to the arms 29 and piston 39 of each being connected to the mast as by a pivoted joint 40. f

For purposes of providing stability to the drill rig while drilling, a pair of hydraulic jacks 41, one on each side of the rig thereof, is provided, these jacks being shown in their extended condition in FIG. 1.

The hydraulic jacks 41 are mounted upon extendable Outrigger devices (not shown) for the purpose of increasing the distance between them when desired and thus enhancing drill stability.

The means for raising and lowering the auger 21, as shown in FIG. 1, includes a cable drum assembly 42 which will be described in greater detail hereinafter. This cable drum assembly is operatively associated with the crown assembly 22 of the auger by a system of cables which will be described in connection with FIG. 5. The cable drum assembly 42 is driven, in the form' shown, by means of an hydraulic motor 43 which receives hydraulic fluid, such as oil, from one or more hydraulic pumps 44. In FIG. 1 only a single hydraulic pump 44 is shown although we have found it advantageous in this form of the invention to employ two such pumps which may be connected individually or jointly to the hydraulic motor 43. For purposes of simplicity the hydraulic interconnections between the pumps 44 and the motor 43 are not shown.

The hydraulic motor 43 is operatively connected to the cable drum assembly 42 by a suitable power multiplying means, in this form comprising two pairs of sprocket wheels 45, 46 and 47, 48. The pair 45 and 46 are respectively of large and relatively quite small diameter and are coaxially mounted upon a jack shaft 49. The sprocket wheel pair 47, 48 respectively of relatively large and small v diameters are in the form shown mounted coially with the pivot shaft 26 of the rnast 23.

The hydraulic motor 43 is operatively connected to the sprocket wheel 45 by a suitable roller chain 50 and in turn the smaller sprocket 46 is drivably connected to the larger sprocket 47 by a roller chain 51, and the sprocket 48 is connected to a sprocket 52 of the cable drum assembly by means of a roller chain 53.

The aforementioned hydraulic pump 44 is capable of generating high pressure, for example, 5000 p.s.i. (oil) and this is employed for the heavy work required to be done by the apparatus, for example, energizing the hydraulic motor 43 and also for energizing an hydraulic motor which turns the auger 21 located in the crown assembly 22 and which will be described more fully hereinafter.

One or more additional hydraulic pumps, such as 54, are provided for activating, e.g., mast raising cylinder 38 and power cylinders 34 and 35. In the form shown, two such hydraulic pumps 54 are employed. The hydraulic pumps 54- are substantially in alignment with 4one another as shown in the form of FIG. 1. Such pumps are driven by any suitable power source, for example, an internal combustion engine 55 which drives same by means of a main pulley 56 which is, by means of endless belts, driv ably connected to a pump drive pulley S7, the latter in turn via universal couplings 58 and 59 directing torque to such pumps 44 and 54. On the opposite side of the rig, as viewed in FIG. 1, a similar pair of pumps, such as 44 and 54, are located and are sim-ilarly driven.

In order to support mast 23 when in its inactive horizontal position, there are provided a pair of vertically extending posts 60 and 61 which are mounted respectively upon the forward portion of the deck 32 and the front of the'truck 27, which posts are provided with bifurcated upper elements or cradles, as at 60a and 61a respectively, for supporting the mast as aforementioned when the latter has been lowered under the influence of the hydraulic mast raising and lowering power cylinder 38.

Secured to a vertical mounting plate 62 are three hydraulic valves 63, 64 and 65 which respectively perform the following functions:

(a) Valve 63.--This valveV controls the auger drive motor (to appear more fully hereinafter) locatedy in the crown assembly 22 at the top of the auger 21. The latter motor is sometimes referred to as the rotary drive motor.

(b) Valve 64.-This valve controls the cable drum drive motor 43.V

(c) Valve 65.-This valve is a so-called selector valve which is capable of directing oil or some suitable hydraulic medium either to said auger drive motor in the crown assembly 22 or to the auger hoist motor 43.

The valves 63, 64 and 65 are under the control of suitable manually operable levers as will be described in connection with FIG. 6., The valve 64, -in addition to being controlled by a manually operable lever, as will 'be described in connection with FIG. 2, is also controlled by a servo mechanism responsive to pressure measured at or near the lower extremity or tip f the auger as will be described more fully' hereinafter. The aforementioned hydraulic system is provided with an oil reservoir 66.

For purposes of clarity, the system of hydraulic conduits are not shown in connection with FIG. l `or in connection with FIG. 6, although a portion of such conduits are shown in FIG. 2 in a schematic manner, it being understood that the system of hydraulic conduits in the present apparatus is laid out in any suitable manner to achieve the specified functions of the apparatus.

Referring now to FIG. 3, there will be described the portions of the apparatus comprising the crown assembly 22 aforementioned. Such crown assembly 22 is schemat-l ically shown in FIG. 3 and comprises a crown frame or mounting 67 upon which the various elements comprising same are mounted. These elements embrace hydraulic motor 68 which is designed for turning the auger 21 via a suitable operative interconnection which will now be described: Y

The auger 21 is provided with a hollow stem 69 consisting, in the form shown, of two concentric coaxial tubes, the center one 70 for conducting the cementitious mixture or grout from the top of the auger to the drill tip thereof and thence into the cavity drilled in theearth; and an outer tube 71 for the purpose of conducting the drilling medium, such as drill mud or water to the lower end of the drill. The stem 69 thus comprises a hollow tube to which are rigidly secured the helical yflights of the auger.V o

Suitable bearing means comprising thrust bearings and weight supporting bearings are provided for the auger, such bearings being schematically indicated at 72. j

. The hydraulic motor 68 transmits torque to the stem 69 of the auger 21 via a pair of bevel gears 73 and 73a, the latter comprising a bevel gear of substantial diameter which is horizontal in attitude, as shown in FIG. 3, and which meshes with the bevel gear 73, the latter being substantially vertical as shown in this gure.

f T'husthe shaft of the bevel gear 73ais in effect the stem 69 of the auger.V Shaft 74 of the bevel gear' 73, on the g, other hand, is perpendicular. to the .axis of they stem A69. A 'suitable power multiplying device consisting of ay series of sprocket wheels interconnected by suitable roller chains drivably connects the hydraulic motor 68 to the shaft 74as follows:

A sprocket wheel 75 is driven directly by the motor 68 via an output shaft thereof and such sprocket wheel '75 in turn drives a pair of coaxial sprocket wheels 76 and 77 which are rigidly secured to a common Vshaft 78, the driving thereof being accomplished via a roller chain 78a. The sprocket wheel 76 is of substantially larger diameter than that of 77. The latter in turn is drivably connected to said shaft 74 via a further sprocket wheel 79 of substantially larger diameter than that of` 77, this connection being accomplished via a rollerchain 80. It is, of course, understood that the shafts 78 and 74 are suitably mounted upon the crown frame 67. Via the bevel gear 73a rigidly secured to the stem 69, torque is communicated to the 4auger 2i to turn same and thereby to sink the drill into the earth as shown in FIG.. 2.

The drilling medium, such as .water or drilling mud, is communicated to the outermost of the two conduits, namely the tube 71 aforementioned, via a device referred to as a swivel S1 and consisting of a relatively stationary collar 82 which is mounted upon Ythe frame 67, and which surrounds a portion of the tube 71 having an orifice 83 therein through which the'drilling medium passes into such tube71. The drilling medium is Vconducted to the swivel 8l. via a conduit 84 at a selected pressure and from a suitable source. A suitable packing or. lgland construction, as at 35, is provided for preventing leaking of the drilling uid despite the rotation of the rotating stem 71.

The cementitious mixture, such as grout or pumpable concrete, in turn is'communicatedV to the hollow stemmed auger drill via a swivel S6 having a stationary ycollar portion 87 which is associated with the rotatable inner conduit 7) via agland or, packing 88 thereby to prevent leakage of the cementitious mixture as it is pumped under pressure into such conduit 70. The stationary portion S7 of the swivel 86 in turn is in communication with the source of the cementitious mixture under pressure via a rigid conduit 89which is secured to a flexible conduit 90 by a suitable joint. As the crown assembly 22 moves up and down vertically IdurinsT the operation of the apparatus, the cementitious mixture and the drilling mediumV are 4communicated thereto via the flexible conduits 84 and 90 respectively thereby avoiding the. disadvantage of having to mount containers of these substances upon the vertically movable carriage or frame 67.

Referring now to FIG. 5, there will be described the means for raising and lowering the crown assembly 22, such means being designed for the purpose not only of applying -a hoisting or lifting force to the auger, but also a force referred to as a down-crowding force by which the auger is urged intov the earth forcefully, that is, by force other than that attributableV to the weight 0f the auger and its crown assembly 22. f The cable drum assembly 42 (FIG. 5) is operatively connected to the hydraulic motor 43, via an interconnection gli. The cable drum .assembly 42 or hoist drum has wound about it a hoisting cable 92, an uphoist portion 92a of which passes respectively over a crown sheave 93 (mounted on mast 23), under a cable sheave 94 mounted on the crown assembly frameor carriage 67 and thence over another crown sheave 95 (also mounted on mast 23) and thence to theupper extremity 96 of a vertically movable piston 97 of a crowd cylinder` 98 which isrigidly secured to the mast 23 as shown in FIG. l. The portion 96 comprises a link'between the uphoist portion of the cable 92a and the piston 97. On'the otherhand, a downhoist portion g2b Vof. the cable 92 passesover a fleeting sheave 99 which is rotatable upon a shaft '100 having a stationary axis. Y ,Y A Y From the fleeting sheave 99 the downhoistcableportion 92h passes over a crowdcable sheave ltllfwhch isV 9 i mounted for rotation upon the rear of the crown frame 67 of the auger drill and from thence the cable portion 92b passes downwardly, as viewed in FIG. 5, and under a down hoist sheave 102 which is mounted for rotation upon the lower region of the mast 23 about a stationary axis. From such sheave 102 the downhoist cable portion 92h is secured, as by link 103, with the lowermost extremity of the piston 97 of the crowd cylinder 93.

The function of the crowd cylinder is to provide a ne adjustment to the positioning of the auger with respect to its vertical movement or, if desired, it can provide additional up or down force by the application of fluid under pressure on the proper side of a piston 104 thereof. The crowd cylinder piston may have a travel, for example, of i4 feet from its central location or a total range of about 8 feet.

The hydraulic motor 43 turning the hoist drum 42 thus can lift the auger or it can exert a down force there- In order to obtain an indication of the downhaul or downhoist pressure, there is connected to conduit 98a (FIG. a downhaul pressuregauge 105. Such gauge may be employed not only for measuring downhaul pressure but also uphoist pressure as exerted by the crowd cylinder 98.

Referring now to FIG. 2, there is shown at 106 the pumping means for the cementitious mixture, such as grout, such pumping means comprising: a pump 107 which may be constructed in accordance with the apparatus shown in U.S. Patent No. 2,796,029, anda suitable pump drive 108. In this instance the pump drive comprises an internal combustion engine. The cementitious mixture is mixed ina hopper 109 and fed by means of the conduit 110 in the bottom thereof into the inlet of the pump 107.

To the outlet of the pump 107 there is secured by a suitable joint the lowermost extremity of the iiexible conduit 90 which is connected to the swivel 87 of FIG. 3.

The internal combustion engine or power drive for the pump 107 is provided with a suitable speed control schematically indicated at 111 and a clutch as at 112. The speed control 111 embraces a hand lever or throttle 113 which is connected by suitable means to a carburetor 114 of the engine 108. v

The clutch 112 in turn is controlled by a hand lever 115 which, via a clutch control means 116, governs the aforementioned clutch 112.

Referring now to FIG. 6, there will be described the manually controllable vlevers and handles at the control station for the apparatus and also the instruments which are immediately visible to the operator.

The internal combustion engine has a starter and ignition control panel at 117 embracing a starter button 118 and an ignition switch 119.

On the lefthand portion of the control station there are provided four levers 120, 121, 122 and 123 which are respectively movable in the direction of the arrows shown and for the following purposes:

Lever ]20.-For controlling the azimuth or angular adjustment of the deck 32 under the influence of the hydraulic power cylinders 35. An adjustment of i40 from the centerline of the truck can be made by lever 120. i Lever 121.--For controlling the fore and aft sliding motion of the-deck 32 under the influence of hydraulic cylinders 34 and whereby line adjustments in the positioning of the auger drill can be made along such fore and aft line. By a joint control of the hydraulic cylinders 34 and 3S the auger drill can be accurately placed.

Lever 122.-This lever controls the flow of hydraulic uid under pressure to the hydraulic mast raising cylinder 3S thereby to raise or lower same.

Lever .723.-This lever controls the hydraulic fluid under pressure to the crowd cylinder 98 (FIG. 5) to provide fine adjustments in positioning of the auger to aid in positioning its crown assembly, for example, for joining sections of the auger together or alternatively it can be used to aid in downcrowding the auger during drilling or to hoist same when it is to be lifted out of the earth.

The internal combustion engine 55 is under the influence of throttle lever 124 and engine choke lever 125.

The internal combustion engine for the cementitious mixture pump 107 is under the Ainfluence of the throttle lever 113, as described above, and also under the influence of the clutch control lever 115, both of these levers being preferably positioned within easy reach of the operator of the apparatus.

Main hydraulic levers 126 and 127 are employed which are respectively:

(a) For directing oil to the selector valve 65 from either the pump 44 (FIG. l) or a second pump 44a (not shown), each of these pumpsbeing capable of delivering fluid under 5000 psi.; and Y (b) For controlling the hoist under slow conditions.

A lever 128 is provided for directing the high pressure hydraulic fluid from, eg., the pump 44 either to the hoist hydraulic motor 43 or to the drill drive or rotary hydraulic motor 68 in the crown assembly 22.

A lever 129 can be moved either to the reverse condition or the forward condition, as shown in FIG. 6, this lever controlling the direction of rotary motor 68 and thus governing the direction of angular motion of the auger 21. When the lever 129 is in the forward position, the hydraulic or rotary motor 68 causes the auger to drill into the earth in a downscrewing direction and when the lever 129 is in the reverse position, the reverse is true.

A lever 130 controls the direction of rotation of the hoist motor 43.

A hoist brake (not shown) is under the control of a lever 131 which is movable either by foot or by hand to the off or on positions.

There is positioned in a location convenient and easily visible to the operator a control panel 132 at which there is localized the several instruments which should be under examination by the operator and including the aforementioned auger downhaul pressure gauge 105 and also an auger torque pressure gauge 133, the latter reflecting the torque exerted by the rotary auger turning motor 68 and connected as schematically shown in FIG. 2.

Also on the control panel are:l A depth-volume integrator indicator 134, the operation of which will be explained hereinafter; also an auger depth indicator 135; and a grout or cementitious mixture desired or norm pressure indicator 136.

The operative interconnection of the several instruments on the control panel will be set forth more fully hereinafter in connection with the description of the system shown in FIG. 2.

As aforementioned, in the preferred form of the present invention, the auger is of the hollow stem variety having therein two passages, one for the cementitious mixture or grout and another for the drilling medium, such as mud or water. Preferably the drill stem is divided into two coaxial passages one of which embraces the other as has been described above in connection with FIG. 3. That is, the central conduit or tube '70 is for the passage of the grout or cementitious mixture and the second conduit 71 comprising a coaxial and embracing tubular member is for the water or other drill medium. It is possible for the functions of these passages to be reversed and for the center one to conduct the drill medium and the outer one the cementitious mixture in which event valve means therefor are employed at the lower drill end to accommodate such change.

The present invention employs a novel grout valve or cementitious mixture valve, it being understood that whenever the expression grout is employed herein there is embraced cementitious mixture. The grout valve is designed in such a way that during the sinking of the auger drill into the earth such valve is closed and there is thus prevented the .escape of anygrout from the lower end of the auger. However, during the drilling the drill ing fluid, such as water, is directed into the excavation as the. drill is sunk into the earth, for example, by increasing the pressure therein to a point adequate to overcome one or a plurality of Vpoppet valves which are -arranged in the outer surface of the conduit 71 and as shown in FIG. 13.

In the present invention the grout valveis constructed so that when the drilling is under way the central grout conveying passage is sealed and thus prevented from being plugged by the earth as the drilling7 proceeds, but on the other hand is constructed is such a way that when the auger is hoisted out of the earth and withdrawn the grout valve is automatically opened to permit the escape o f the grout or other cementitious mixture thereby to till the cavity formed beneath the auger.

This is well illustrated in FIGS. 13-15 which show a preferred formof grout valve employed at the lower extremity of the drill in the present invention, such valve being in its closed condition as shown in FIG. 13 and in its open condition in FIG. 14.

Thus in FIG. 13'there is shown the lower extremity of the auger 21 employing a preferred form of grout valve designated in general by the numeral 137 and embracing the following construction: to the lowermost extremities of the coaxial tubes 70 and 71 there is secured as by welding a anged tubular element 138 having an upper collar or flange 139 which performs .the function of closing the bottom extremity of the drill medium passage namely the conduit existing between the inner tubular member 70 and the outer tubular member 71. Thus the flange 139 prevents the progress of the drilling uid such as water past the upper surface of such flange 139 it being possible for the water or other. drilling medium to escape 'from the lower region of the auger e.g. via one or more poppet valves one of which is shown at 140. Such valve 140 includes a valve plate 141 having a valve stem 142 the latter being urged inwardly to force 'resiliently the plate 141 against the outer surface of the outer stem 71 with the aid of a poppet valve spring 143 which is interposed between the inner surface of the .tube 71 and a poppet washer 144 secured to the stem 142. Thepoppet valve can be adjusted to open in response to any desired fluid pressure within the conduit 71. Alternatively any suitable form tof valving arrangement can be employed for permitting the water or drill medium to escape from the lower end of the auger but yet prevent the entrance of soil to plug the drill medium conduit. For example, a :one way Hap or check valve 140e (FIG. 7) can be employed which is hinged to tube 71 in such a location that when the auger is turned the hinge is in the leading position and when the auger has stopped rotation the drilling medium can escape by pressing against the hinged flap.

Reverting to the flanged tubular member 138, in FIG. 13 it is shown that this member comprises an extension of the grout or cementitious mixture conduit 70, such tubular member 138 having an outwardly belled or outwardly Haring cross-sectional area to inhibit the formation of grout or cementitious plugs at the lower exremity of the drill. Thus, the cross-sectional area of the grout passage gradually is increased starting from the uppper extremity of Vthe tubular member 133 and ending at the lower extremity which coacts with a grout valve plate 145. 'Ihe upper face of the grout valve plate 145 is shown at 145a and coacts with the lowermost annular edges 138a of the tubular member 138 thereby to close the valve and prevent the escape of the grout during drilling in the manner shown in FIG. 13. Y

The grout .valve plate 14S is axially movable with respect to the tubular member 138 by virtue of a plurality of vertical cylindrical posts 146 of suitable metal, there being fourV employed in the embodiment shown separated by 90 intervals, such posts beingvrigidlysecured about the margin of the grout valve plate 145 asby welding. Such posts passfthrough aligned passages,V as at 147, formed in the helix of the auger 21.

A furtherfunction of the vertical posts 146 is to communicate torque to a cutter head 14S which is secured to the groutvalve plate 145. This, is accomplished by means of a pair of perforated collars 149.and 151B which are horizontal in attitude as shown in FIG. 13 and which have aligned pasages through which'pass the four vertical posts 146,- there being suitable clearance to permit free axial movement of such posts, thereby tov permit relative axial movement of the cutter head 148 Ywhen the drill is hoisted as will be described hereinafter. The cutter head 148, in the form shown,` isof the fishtail .variety although any suitable type of. cutter head r may be employed. Y

The cutterhead-148 is secured to the grout -valve plate 145 as follows: such valve plate 14,5 haspassing centrally therethrough va cylindrical collar 151'which is rigidly secured to v.such plate as by welding and which is also provided with a passage 152 therethrough of square cross section which is well shown inv FIG. 15. The hollow collar 151 thus is adapted to receive a square stud or post 153 which is secured rigidly to Vthe cutter head 148, the square post`153 being secured Within the collar 151 as by a bolt 154 which passes vdiametrically through both. The'cutter head 148 thus is removable for substitution of varying types of cutting heads as desired.

Thus torque communicated to the auger 21 is communicated to the cutter headv148 via the tubular element 138, the perforated collars 149, 15) and the four vertical posts 146 which in turn cause the grout valve plate 145 to rotate and thence to communicate the turning force to the cutting head via the interfitting parts 151 and 153 above described.

The length of the posts 146 and the disposition of the perforations through/which they pass and also the shape of the tubularmember 138 are .such'that the grout valve plate 145 can lit closely against the lowermist surface 138e of the element 138 to assume theV positions shown in FIG. 13 during the sinking of the auger.

It will be noted in FIG. 13 thatk the helical surfaces of the auger 21 .proceed down to the cutting edge 155 which is the lowermostedge of the helix and which is immediately above -the -axially shiftable grout valve plate 145. The outermost diameter of the iishtail cutter head `14S is substantially equal to the outermost diameter yof the collar 150. Such diameter ofthe lishtail cutter head is somewhat greater than or at least equal to the outer diameter of the grout valve plate 145. Y i Referring .to FIG. 14, the auger 21- instead of being urged downwardly as at FIG. 13 is undergoing a hoisting or uplifting motion and this has caused an opening of the grout valve 137 by virtue of grout pressure-:within tube 71) and the weight of the cutter head 148 and the parts thereof which may shift axially therewith including the grout valve plate 145, and the several posts 146. The relative axial movement ofthe grout Valve plate 145 is limited by meansv of limit-stop pins 156, there being one each in the upperextremities .of each of the vertical metal posts 146 and each of whichfcoacts with the. upper surface .ofthe perforated collar 149 to prevent the detachment of the cutter head 148 and its valve plate 145 attached thereto. The degree of opening of the grout valve 137 is selected to be adequate for the desired maximum flow rate of the grout, bearing in mind the constituents thereof, the outermost marginof the plate 145 preferably 'being tapered downwardly as viewed injFIG. 14 to facilitate the exit of the grout or other cementitious mixture in the manner shown in such FIG. 14. n Y .The auger construction of FIGS. 19-21, inclusive, will now be described, it being similar to that of FIGS. V13-15, inclusive, withthe exceptions set forth. Y This construction is forthepurpose of installing concurrentlywith the injectionof the cementitiousmaterial a reinforcingbar Seoane@ centrally of the pile and, if desired, one or more bars radially spaced from and preferably symmetrically situated about such center. This is accomplished by employing an expendable cutter head 14ga having, for example, two radially extending cutting fins 148]), such expendable cutting head being separable from the valve plate 145 and having secured centrally thereto a stud 153 which is of square cross-section and analogous to the stud 153 of FIG. 13, such `stud 153 having integrally secured thereto and extending coaxially thereabove a reinforcing rod or bar 153e which extends to any desired height up into the tube 7 0, for example, high enough to be above ground level when the drill is fully withdrawn from the earth. The reinforcing bar 153e may be of square cross-section, the same as the stud 153', or, as shown, it may be of circular cross-section. In any event, the cross-sectional shape and size of the bar 153e is selected to be easily slidable through the central passage formed in the collar 151.

The aforementioned cutting head or drill bit 14361 being expendable, may be of an inexpensive variety.

The pile is drilled in the manner set forth above using the bit li-Sa and the downcrowd force during augering holds it firmly as shown against the bottom face of the valve plate 141-5, the bit tending to keep the stem on center.

Thus when the hole has been drilled to its final depth, as above described, and the grout pump started, the grout valve 137 will be opened by the combined action of gravity and grout pressure acting on the plate 145. This will move the expendable drill bit 14de and its reinforcing bar 153a downward with respect to the stern of the drill. The central portion of the stem during injection of the grout will cause the bit 148e to remain in place at the bottom or point of the pile, such bit 143:1 firmly anchoring the reinforcing bar 153e at the point of the pile. The movement of the grout through the tube 7d during withdrawal of the drill tends to hold the reinforcing rod 153e positioned in the desired centered location. The injection of the grout or other cementitious material continues while the drill is withdrawn until the drill stem is clear of the ground level at which time the lower extremity of the stem is lifted off of any remaining portion of the reinforcing rod 153:1 which protrudes above ground level.

Also, if desired, in addition to or in lieu of installing the central bar 15311 as above, one or more additional reinforcing bars can be `analogously installed concurrently with the injection of the grout, which additional bars lare radially spaced from the center of the pile and close to the pile outer surface. Often pile reinforcing specifications require the use of such multiple reinforcing bars in such radially spaced positions so as appreciably to increase the bending strength of the pile.

Such reinforcing bars radially spaced from the center of the pile are placed as follows: along the outer surface of the drill stern 69 (which, for example, may be of 8 inch outer diameter) there lis located one or more hollow guide tubes 153i), each of which extends from near the lower end of the helix along the sides of such stem 169, one such guide tube being provided for each reinforcing bar which is to be placed. In the form shown in FIGS. l9 2l there are four such guide tubes 15311 for receiving four reinforcing bars 153C which are spaced about the longitudinal axis of the auger separated by 90 intervals. Each such guide tube 15315 is terminated at the endregion of lthe auger helix, the mouth of each such tube opening upon the lower face of the last turn of the helix. For example, a lowerrnost mouth of a guide tube is preferably located at or near the lowermostportion of the helix and the next lowermost mouth of a guide tube is located on the underside of the helix -but spaced upwardly therefrom to the extent of 90 of the helix, and so on.

The lengths of the guide tubes 1531; correspond substantially to the lengths of the reinforcing bars 153e therein. For example, in the case of a pile requiring reinforcing in its upper 2O feet, the pile being, forexample, 30 feet in depth, such guide tubes 153e will be approximately 20 feet long. The bars 153C are inserted into the aforementioned lowermost mouths of the tubes 153i). Each such bar is provided at its lower extremity with a flat washer or disc 153d which functions to prevent it from being pushed up inside the tube 1531; during drilling. At the upper extremity of each bar 153e there is provided a sufiicient protrusion above the top of its respective tube in order that a pin, such as 153e, can be inserted in a passage through the bar in order to rest on the top lip of the tube 153b to prevent the dropping out of the bar until the desired time. The pile, which may be of any length, then is drilled employing the apparatus of FIGS. 19-21, and while the auger is being withdrawn, in order to release the reinforcing bars 153C, it is necessary to wait until the top portions of such bars are exposed above ground level in order that the pins 153e may be removed. Thereafter, if desired, in order to start the dropping out of the bars, each may be struck a blow upon the top thereof, as by a hammer, to aid its slipping out of its respective tube as the auger is further withdrawn from the hole. The start of such drop-out of bars 153C can be concurrent with or later than that of bar 153e. The guiding action of the Atubes 153b keeps such bars equally spaced insuring their accurate location in the pile. Substantially semicireular portions of the valve plate are cut away (FIGS. 19 and 20) respectively as at 145a to permit the dropping out of the reinforcing bars 153C.

Referring now to FIGS. 22, 23 and 24, there is there shown a modification of FIGS. 19, 20 and 2l which is identical thereto except that reinforcing bars 153e (FIG. 22) instead of terminating just beneath the helix 2,1, in the manner of bars 153C (FIG. 19), extend therebelow through perforations in the valve plate 145 and down to a bottom plate 148C of an expendable drill bit 148:1', to which they are secured as by welding. Reinforcing bar guide tubes 153b (FIG. 22) therefor are also downwardly continued whereby they extend down and loosely through such perforations in valve plate 145 and terminate preferably just beneath the lower surface thereof (FIG. 22) when the valveis closed. In contrast to FIGS. 19-21, in the modification `of FIGS. 22-24, the release or drop-out of all the reinforcing bars 153e and 153e commences concurrently because all such bars are secured to the same bottom plate, namely, 148C'.

An alternative form of valve structure is shown in FIG. 16 which is referred to as a grout-water valve in view of the following construction: during the downscrewing or sinking of the auger into the earth a grout valve is closed and a water or drill medium valve is open, but when the auger has been sunk to depth it is reversed two revolutions which causes the group valve to open and the theretofore open water valve to close.

Such alternative form of construction of FIG. 16 is broadly designated by the numeral 1,57 andk consists of an outer stem tube 158 and an inner stern tube 159. The latter is for conducting the grout to the tip of the drill and the space between the latter and the inside surface of the stem tube 15S is for conducting the drilling medium such as water. These two tubes are relatively fixed and do not shift axially relative to one another.

The lower outer surfaces of the inner hollow stern 159 is provided with a plurality of threads as at 161) which engage with threads 16de upon the inner surfaces of a valve sleeve 161 which can undergo relative angular movement thereby to shift axially relative to the tubes 158 and 159.

The valve sleeve 151 is provided with drilling medium valve surfaces 162 coaxial with its lower region the latter having orifices 163 for moving into register with orifices 164 in the lowermost portion of the outer tube 158 as shown in FIG. 16. Thus during the downscrewing of the auger 21 the drilling medium can escape from the lower portion ofthe drill via the registered orifices 163 and 164i, this by virtue of the relative axial position of the parts as shown in this figure.

Y non with FIGURE s.

'hole from closing in or caving in.

However, during such downdrilling the grout valve is closed this valve comprising a skirt portion 153a along the lowermost periphery of the tube 158 such skirt closing ygrout orifices 165 during this condition. Such grout orifices are formed in a grout valve plate 166 to which is secured a pilot bit (not shown) having a shaft167 -of square cross section which is tted into a central passage in such plate 166. Y

After the augerhasbeen sunk to depth by turning same in a downscrewing direction, thereafter it is turned, for example, two revolutions in an unscrewing direction thereby causing the following operation: the pilot bit being embedded in the earth will cause the valve sleeve 161 to be angularly relatively stationary to the angularly shifting portions 158 and 159 which are turned backward in an upscrewing direction through the aforementioned two revolutions. This will cause the threads 16u, 160:1 to coact thereby in effect to unscrew aV portion of the auger and to shift the valve sleeve 151 in such a Way that the drill medium orices 163 and 164 .are no longer in register but rather are out of register, the orifices 164 being closed by the cylindrical portion 152. On the other hand, the grout valve orifices 165 are Vopened by virtue of the raising of lthe skirt portion 158er .relative to plate 165 in response to the unscrewing motion p f the auger drill.

Referring now to FIGURES 17 and 18, there are shown in somewhat greater detail certain portions of the apparatus as shown schematically and described in connec- Thus the water swivel 81 of FIGURE 3 is shown in greater detail in FIGURE 17 and comprises the above described relatively stationary collar 82 having an annular passage or groove formed internally thereof at 82a to which is directed the drilling Y medium which finds its way into the drilling medium conduit 70 via the passage 83 as shown. The details of the gland or packing 85 are also shown in this FIGURE 17. Y

In the region designated 168 (FIG. 17) is located the vso-called rotary table by which torque is communicated to the auger stem via the bevel gear arrangement 73, 73a described above in connection with FIGURE 3.

Grout pressure control method and means pressure of the cementitious mixture :in the cavity which ris vacated by the drill.

Prior apparatus and methods of this type have failed to provide any adequate information as to the conditions regarding these factors occurring during the forming of the pile.

One of lthe principal objectives of the present invention is to provide novel methods Vand apparatus for maintaining preselected pressures of the grout or cementitious mixture column, as measured near the auger end during withdrawal, at least great enough to prevent the drilled Successful installation of Vpiles of this type, which `are formed by filling with groutthe cavity vacated by the auger as it is extracted from the earth, requires a knowledge Vof pressure conditions of the grou-t in the cavity, preferably grout pressure conditi-ons in the region of the lower extremity of the drill.

Accordingly, in the present invention there is provided a pressure sensing system broadly designated 169 (FIGS. 2, 4 and 7) having a pressure sensing element 1711 for sensing the pressure of the grout in the lower region ofthe auger'drill. The position of the sensing element 171) is Well shown in FIGS. 7 land 13. It is operatively associated Withmeans at the operators station (FIG. 6) for indicating when the grout pressure in the neighborhood of the lowery end of the drill, falls below a selected value which value is different for each level of such drill end. l Y

We have found it desirable in one form to employ a substantially constant volumetric inflow rate of the grout or cementitious mixture into the cavity via the stem, and while withdrawing the auger to control and adjust the rate of withdrawal so that the pressure of the grout in the region of the lower end of the drill will not fall below or'appreciably below the selected norm for each level -of withdrawal of the drill tip as per 'F=IG. 7a. For example, at a depth rof 40 feet of the drill tip it is desirable for the grout pressure to be 4() p.s.i.and at a drill tip depth of 20 feet for the grout pressure to be say 2O p.s.i.

The grout pressure indicating means, in one form of the present invention, which signals to the operator of the apparatus lthe departure of the grout pressure below a selected norm at eachievel of withdrawal, is of the pneumatic variety and is illustrated in connection with FIGS. 4 and 7. In effect the means of FIG. V4 comprises a pressure comparator device with a signal means, and is of the following construction and operation: vthe pressure comparator device is indicated by the numeral 171 (FIG. 4) and comprises an Velement 172 into which is directed, via a pneumatic infeed line 173, air at a selected constant feed pressure of say 150 p.s.i. The element 172 causes small charges of this high pressure APf of air to be directed through an exit port 174 to a conduit 175 which is in communication with the aforementioned pressure sensing element 171i, the conduit 175 and the element 17) comprising the system connected to such exit port. Operatively connected to the element 172 is a signal device 176 which, for example, can -ernit an audible signal, although the invention is not limited to any particular type of signal. However, in this instance the signalling device is of the audible variety land each time the element 172 emits a charge or a pulse lof `the high pressure input air the signal means `176 is actuated to make oney signal, eg., to ring a bell once.

In between these pulses 'of' ysuch high pressure air Pf the-re is made .a comparison between: (a) a desired pressure norm Pn as shown on an indicator 177, and (b) the grout pressure Pg as measured by element 170, the comparison being made pneumatically via an element 173. The indicator 177, as shown in FIG. 4 shows a norm pressure of 45 p.s.i. This indicates the norm pressure Pn against which a comparison is made with the pressure Pg in the system 175, this comparison being made by the coa-ction of the elements 172 and 178.

The element 172 continues t-o discharge the pulses of high pressure air (e.g., at p.s.i.) at intervals until the pressure Iin the ksystem 171), 175 reachesV thepreselected norm pressure which is set or adjusted, as by a wheel 179 which is .operatively connected to the indicator 177 for changing the setting thereof to accord with the desired norm, and lalso is operatively connected to the comparator element178. When the pressure in the system 171i, 175V lreaches theV desired norm theL signal means 176 ceases to operate. Y

The frequency of the audible signals from 176 is a function of the degree of departure of the pressure Pg in the .system 1711, from thedesired norm Pn and as the desired norm is approached the frequency becomes lower and lower until eventually itrbecomes zero indicating that the pressure inthe system 170, 175 is not below the norm.

The conduit 175,`which placesrin communication the pressure sensing element 171) Wit-h the pressure comparator 171, is of a liexible nature, Vas indicated in FIG. 7, between .the exit port 174 and the top ofj the auger, there being a suitable swivel joint communicating the pressure medium to a portion 175e of the conduit which is located within the water passage of the stem 69 of the auger 21.

The pressure sensing element 17 t) in effect is a differential pressure diaphragm device the details of which are shown in FIGS. 8-11 with particular reference to FIG. 10. In the latter figure the pressure differential diaphragm device embraces a diaphragm proper 180 the periphery of which is secured tightly to a diaphragm cup 180:: having a primary chamber 180]) therein which is in communication with the lower extremity of the conduit 175 via a port 189C and a passage 180d. The primary chamber 180b of the pressure differential diaphragm device 170 is separated from a secondary chamber 181 which is coaxial therewith and positioned interiorly of the chamber 180b as is shown in FIGS. 8, 9 and l0. Such primary and secondary chambers are normally separated from one another by means of a valve plate 182 which coacts with a valve seat 133 of ring-like or annular shape comprising the line of demarcation between the primary and secondary chambers 180k and 181. The valve plate 182 is secured to the diaphragm 180 and can shift into and out of engagement with the valve seat 133 in response to certain pressure differentials existing between the primary chamber 1S0b and the pressure acting upon the righthand face of the diaphragm 180 as viewed in FIG. l0.

The primary chamber 180b embraces not only a relatively deep portion liib, as shown in FIGS. 8 and 9, but also concentric and relatively more shallow portions 180e and 18th'- which comprise annular grooves formed concentric with the two coaxial and concentric primary and secondary chambers 180k and 181. The concentric grooved portions 180e and 1801 are in communication with one another via radially extending passages 180g and 186k (FIG. 9).

Thus the air pressure in the element 172 Pg is symbolic of or representative of the pressure in the primary chamber 18012.

Since the exterior face of the diaphragm 1&0 is exposed to the cementitious mixture or grout at the upper reg-ion of the cavity, by virtue of its location near the lower end of the drill, such cementitious mixture exerts pressure against the righthand face of the diaphragmv 180, as mentioned above, and if such grout pressure exceeds that of the air pressure within the primary chamber 18% the valve plate 132 will be pressed against the valve seat 183. Thus if a desired grout pressure at the part-icular level of the pressure sensing element 170 should be 45 p.s.i., for example, by virtue of a 45 foot penetration of the drill and such grout pressure is in fact 45 p.s.i. or greater, then the valve 182, 183 will be closed. Assuming that it has been closed for an adequate period and also that 45 p.s.i. has been set as the norm upon-the pressure comparator 171 (FIG. 4) via the wheel 179, then the audible signaling device 176 will be inoperative because the pressure in the system 170, 175 is not less than the norm. Y

However, if during withdrawal of the stem, and during the injection of the grout into the cavity beneath the auger, the latter is withdrawn at too fast a rate (the grout then being fed at a substantially constant volumetric inflow rate) then the grout pressure will drop and if it falls below the preselected minimum value for Vthe given depth ofthe auger, as adjusted by the wheel 179 upon the pressure comparator, the air pressure within the primary chamber 180!) will exceed that on the righthand face of the diaphragm 180 andthe valve 182, 183 will open thereby permitting the theretofore trapped air in chamber 180b to exhaust into the secondary chamber 131 and thence via an escape port 184 and a passage 185 (FIG. 9) to a check valve 186 thereby permitting the pressure within the chamber 180b to drop to a value approaching atmospheric pressure. At this point the pressure comparator device 171 will immediately start functioning and the signal device 176 will be activated to emit audible signals at a substantial frequency dependent upon the degree of drop of the pressure below' the norm and immediately the operator of the device, by controlling the hoist motor lever 130, or a Vernier control therefor :1 (FIG. 6) will slow down the rate of withdrawal of the auger. In the meantime the pressure comparator device 171 will attempt to rebuild the pressure in the system 170, 17S thereby causing the aforementioned audible signals to cont-inue. The pulses of the infeed air Pf will continue intermittently into the system 171), 175 until the external grout pressure, that is the pressure sensed by the right hand face of the diaphragm 180, is restored to the selected norm (resulting from the slowing down of the drill withdrawal rate) at which time the audible signal means 176 will become inactive.

We have found it advantageous to employ in connection with an auger of for example, 16" outer diameter, l p.s.i. of air pressure for every foot of depth of penetration of the drill. That is the grout or cementitious mixture is injected into the cavity at the 40 foot level under a pressure equal to or greater than 40 p.s.i. Thereafter it is possible manually to reduce the setting of the indicator 177 via the adjusting wheel 179, for example, 5 p.s.i. for each 5 foot increment of withdrawal. Alternatively as shown in FIGURE 2, the adjusting wheel 179 is operatively associtaed with means for changing same exactly to accord with the level of withdrawal of the lower end of the drill. For example, the adjusting wheel 179 is operatively connected to the jack shaft 49 by an operative interconnection schematically indicatedv at 187 in which there is interposed a reducing gear 188 to correlate the revolutions of thepjack shaft 49 with the upward movement of the auger 21.

Thus the pressure comparator'device 171 is automatically adjusted to accord with the level of withdrawal of the auger 21.

As shown in FIG. 2, there is provided in one form of the invention a servo mechanism 189 which is operatively connected to the engine throttle lever 113 vfor the grout pump engine, and also to the hoist motor lever 130, which controls the hydraulic valve 64 of the hydraulic motor 43, to accomplish the following: assuming that it is desired to feed into the cavity grout at a constant volumetric inow rate, the servo mechanism 189 is operatively connected to the pressure comparator and signaling device 171, by means of an operative interconnection schematically shown in 190, in such a way that when the signaling device 176 is activated the servo mechanism will alter the setting of the lever 130 thereby to slow down the auger as a function of the frequency of the signals. That is, the hoist motor control lever 130 will be adjusted tovprovide a norm rate of withdrawal which can be adjusted in a negative direction to slow down the drill withdrawal rate within a selected small range for example, 1 foot per minute which may constitute 10% of the total rate of withdrawal of the drill and by such slowing down will automatically reinstate the desired grout'pressure at the region of the lower end of the drill.

Alternatively, the volumetric inow rate of the grout can be increased via the servo mechanism 189, or either one or both of these factors, namely,'the rate of withdrawal of the drill or the volumertic inflow rate of the grout can be adjusted to reinstate the desired pressure at the lower end of the drill.

Thus, the novel method carried out by the above ascribed apparatus with particular reference to the pres`Y sure comparator device 171 is as follows: (l) drilling a hole in the earth by sinking to a desired depth an auger type drill by turning same, said drill havingy a hollow tubular stem and spiral ilights; (2) thereafter progressively withdrawing the drill from the hole, together with the earth in its flights, by applying a lifting force e.g. to the upper end thereof adequate for this purpose and there-

Claims (1)

1. THE METHOD FOR FORMING PILES IN THE EARTH WHICH CONSISTS IN DRILLING A HOLE IN THE EARTH BY TURNING AN AUGER TYPE DRILL HAVING FLIGHTS AND SINKING THE LOWER END THEREOF TO A DESIRED DEPTH BELOW THE SURFACE OF THE EARTH, THEREAFTER PROGRESSIVELY WITHDRAWING THE DRILL FROM THE HOLE, TOGETHER WITH THE EARTH IN ITS FLIGHTS, BY APPLYING A LIFTING FORCE TO THE DRILL THEREBY FORMING BENEATH THE DRILL A CAVITY OF A VOLUME WHICH PROGRESSIVELY INCREASES AS THE DRILL IS WITHDRAWN, FORCING A FLOWABLE PILEFORMING SUBSTANCE INTO THE CAVITY RESULTING BENEATH THE UPWARDLY MOVING LOWER END TO PROGRESSIVELY FILL SAID CAVITY AND SIMULTANEOUSLY MEASURING THE RESPECTIVE FLOW VOLUME RATE OF THE SUBSTANCE BEING PROVIDED TO THE LOWER END OF THE DRILL, FURTHER SIMULTANEOUSLY AND CONTINUOUSLY MEASURING THE DEPTH OF SAID END OF THE DRILL BELOW THE SURFACE WHILE MEASURING THE RESPECTIVE PRESSURE OF THE FLOWABLE SUBSTANCE AT THE PARTICULAR LEVEL OF SAID MEASURED DEPTH, AND BASED ON THE RESPECTIVE MEASURED DEPTH, VARYING SAID FLOW VOLUME RATE OF SAID SUBSTANCE UNTIL THE MEASURED PRESSURE CHANGES TO SUBSTANTIALLY MATCH THAT OF A PRE-SELECTED AS DEMANDED FOR SAID RESPECTIVE MEASURED DEPTH ON A PRESSURE GRADIENT PREDETERMINED FOR SUCCESSIVE LEVELS OF DEPTH MEASURED BELOW THE SURFACE OF THE EARTH, AND REMOVING SAID DRILL FROM SAID HOLE AND LEAVING SAID FLOWABLE SUBSTANCE TO BE HARDENED IN THE CAVITY AND PROVIDE A SOLID LOAD-BEARING PILE.

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