US2920455A

US2920455A - Method for forming concrete piles

Info

Publication number: US2920455A
Application number: US547241A
Authority: US
Inventors: Leo W Ryser; Ward W White; James D Brown; Henry A Franklin
Original assignee: PETER KIEWIT SONS Inc
Current assignee: PETER KIEWIT SONS Inc
Priority date: 1955-11-16
Filing date: 1955-11-16
Publication date: 1960-01-12
Anticipated expiration: 1977-01-12

Description

Jan. 12, 1960 w. RYSER ETAL 2,920,455

METHOD FOR FORMING CONCRETE FILES Filed Nov. 16, 1955 3 Sheets-Sheet 1 I 57 7' 1 as ill .5 I1

IN VENTORS A ORNEYS' Jan. 12, 1960 w, RYsER ETAL 2,920,455

METHOD FOR FORMING CONCRETE FILES Filed Nov. 16, 1955 3 Sheets-Sheet 3 E17- g H 33 2: ;.3

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United States Patent-"Q 2,920,455 METHOD FOR FORMING CONCRETE PILES Application November 16, 1955, Serial No. 547,241

1 Claim. (Cl. 61-57) This invention relates broadly to the production of concrete piles and in its more specific aspects it relates to a method and apparatusv whereby poured-in-place concrete piles are rapidly and efficiently produced; and the nature and objects of the invention will be readily recognized and understood by those skilled in the arts to which it relates in the light of the following explanation and detailed description of the accompanying drawings illustrating what I at present believe to be the preferred embodiments or mechanical expressions of my invention from among various other forms, arrangements, combinations and constructions, of which the invention is capable within the spirit and scope thereof.

In construction work where concrete piling is required it is conventional practice to drill a hole in the ground to the proper depth with an earth auger and to then withdraw the auger whereupon the pile is formed by pouring concrete into the hole. Concrete piles are of course used in many different ground formations and classes of earth and we have encountered many difliculties'and inherent problems in forming piles in the conventional manner, and our present invention is directed toward and does solve the many undesirable aspects and operational problems which have heretofore caused the forming of piles to be a slow, expensive and relatively difficult construction process.

'In conventional methods of forming piles the nature of the soil in which the hole has been drilled may be such that after the auger is withdrawn the wall of the hole will collapse or cave in so that the next step in the process of pouring the concrete may not be accomplished. When such a cave-in occurs it is necessary to re-drill the hole or remove the dirt in some way and to shore up, rei'n'force or stabilize the walls so that the hole may be kept clear and the concrete poured to form the pile.

Various means have been devised for stabilizing the soil to prevent cave-ins following withdrawal of the auger. For instance, treatment of the soil with stabilizing chemicals has been suggested and tried, and structural apparatus for preventing cave-ins and collapse of the walls have been used. However except in ideal soil conditions such methods and operations are very difiicult and are obviously expensive and time consuming.

"'Our studies and experiments in this field resulted in the development of the concept which involves the use of the drill or earth auger itself as the stabilizing medium for the wall of the hole into which the concrete is to be poured. It will be recognized that this conception and the method and apparatus whereby it may be practically carried out, eliminates the time consuming steps of removing the auger after the hole has been drilled, then stabilizing the walls of the hole if the soil will permit and then pouring the concrete.

need for certain apparatus and materials which were required in the practice of prior methods, and it ensures against cave-ins while prior methods were, at best, uncertain;

Not only does our concept involve the saving of time but it also eliminates the ice In practicing our method of producing poured-in-place concrete piles we do not remove the earth auger immediately following the operation-of drilling the hole to the proper depth, instead the auger is gradually withdrawn from' the hole as the concrete is pumped in through the auger itself. Thus, the auger forms at all times the wall reinforcing means for that portion ofthe 'hole which has not been filled with concrete. It will be fully appreciated as the description of our method and apparatus proceeds that the concept of slowly withdrawing the auger as the concrete is poured eliminates the need for certain heretofore required extra equipment and materials and reduces the number of steps to be performed in forming concrete piles, and our invention therefore constitutes a substantial saving in labor, time and materials without sacrificing the strength or efiiciency of the finished pile,

Iu order to provide practical equipment to carry out our method of using the earth auger as the stabilizing or supporting means for the walls of the hole while pumping or otherwise causing concrete to flow through the auger and into the hole while withdrawing the auger as the hole is filled with concrete, we evolved an earth auger of novel construction and also supporting and operating equipment of an ingenious nature whereby the efliciency of our operation is substantially advanced.

. The drill or earth auger which we have evolved is of generally tubular construction so that a duct or core is provided therethrough through which the concrete flows into the hole, Since the auger which is used as the sta bilizer for the walls of the hole is the one which has drilled the hole in the ground it is provided with a cutting bit on one end which must be so designed that it will not obstruct the flow of concretefrom the drill into the hole. Because of the consistency of the concrete the complete flow course provided in the drill must be designed for free-and unobstructed flow of the concrete if eificient and satisfactory results are to be obtained. We

have designed the bit of our earth auger so that it affords free flow of the concrete into the hole which the auger has drilled and we have also designed the bit to act as a spreader for the concrete as it flows from the auger and into the hole.

It will be recognized that during the drilling operation it will be necessary that the duct or tubular core of the auger be kept free of the excavated material so that the concrete may flow therethrough at the proper time. We

' have designed a bit or drill tip which functions in this desirable manner for it deflects the excavated material radially outwardly away from the lower outlet from the concrete flow duct through the auger to ensure against such excavated material entering and clogging or obstructing the duct.

augeras a wall stabilizing medium and of forcing con-- crete through the auger as it is withdrawn from the hole which has been drilled thereby we have devised a novel rig for supplying the concrete to the auger and for controlling the auger in all of its various operations in carrying out the steps of our method.

Claims directed to the auger are not presented in this application but are included in our copending divisional 1 application Serial No. 693,094.

With the foregoing general objects, features and results in view, as well as certain others which will be ap parent from the following explanation, the invention consists in certain novel features in design, construction, mounting and combination of elements, as will be more full and particularly referred to and specified hereinafter.

Referring to the accompanying drawings:

Fig. 1 is a view illustrating the rig and mobile equipment we may use in drilling holes and pouring concrete thereinto while following the method we have devised.

Fig. 2 is a view in elevation of the earth auger of this invention.

Fig. 3 is a view in elevation of the bit or tip of the earth auger with parts of the auger being broken away.

Fig. 4 is a view in elevation of the bit or tip of the earth auger rotated approximately 45 from the position illustrated in Fig. 3.

Fig. 5 is a view taken on line 55 of Fig. 3.

Fig. 6 is a front view in elevation illustrating parts of the rig and particularly the mounting and arrangement of the concrete pressure part, drill table and air motor.

Fig. 7 is a side view in elevation of the parts of the rig illustrated in Fig. 6.

Fig. 8 is a plan view of the lower end of the earth auger particularly illustrating the bit or tip of the auger.

In Fig. l of the drawing we have illustrated schematically the equipment required in practising our method of constructing foundation substructures in place, such as poured-in-place concrete piles. This equipment may include a mobile crane 1 having the usual boom 3 extending therefrom. A superstructure, or framework 5 may be supported on the ground adjacent the spot where the hole is to be drilled, the superstructure being positioned and controlled by the crane by means of a swivel 7 to which lines 9 and 11 extending from the boom are attached. Leads or rails 13 (Fig. 6) are provided on the superstructure or framework 5 for a purpose to be hereinafter described.

We provide a sliding platform or elevator which is mounted on the superstructure 5 for movement therealong in either direction. This sliding platform supports the earth auger in different raised positions relative to the ground, the mechanical means for operating the auger and the concrete supply, tank, all as will be explained.

The sliding platform or elevator may consist of two vertically spaced floors or supporting

surfaces

15 and 17 which are connected together by braces 19 to form a unitary supporting or elevator structure which is slidably mounted on the superstructure or vertical framework 5 by means of shoes 21 adapted to slide on the leads or rails 13. The platform is movably maintained in any desired position along the superstructure by means of a hoist line 23 which is connected to the platform or elevator in any suitable manner, the hoist line extending over the top of the superstructure as at 25 and then to the crane where it may be Wound and unwound on a usual drum or the like at the will of the operator. Thus, by winding or unwinding the cable or line 23 the position of the elevator on the superstructure and the distance thereof from the ground may be changed.

We have used the numeral 27 to designate the earth auger in its entirety. The earth auger is formed with a tubular shaft or stem 29 which extends through the

platform

15 and 17 when the auger is mounted and supported in operative drilling position. The drill or auger stem extends upwardly above upper platform 17 where it is associated with any suitable drill table 31 which is supported by the upper platform 17.

A concrete pressure pot 33 is supported from the upper platform 17 by means of braces 34 above the drill table 31 and is formed with a lower tubular concrete outlet 35 which is in communication with a swivel 37 associated with the drill table and the upper end of stem or tubular shaft 29, The construction is of such nature that concrete may flow from the pot 33 through outlet 35 into the swivel 37 and into the upper open end or mouth of the shaft or stem 29 of auger 27. The concrete in concrete pot 33 may be subjected to a head of pressure for insuring proper flow of the concrete from the pressure pot and into the drilled hole. Compressed air is generated by a compressor 39, the air being carried to the pressure pot by means of a flexible hose 41.

Compressed air from the compressor is also supplied to an air motor 43 by means of a flexible hose 45. The air motor is mounted on platform 15 and is adapted to cause rotation of the auger and is operatively connected therewith in any suitable manner, as by transmission 47 and a chain drive 49. The equipment preferably includes a pressure pot loading bucket 51 which is adapted to be hoisted in any suitable and usual manner up the superstructure to the pressure pot for dumping its load of concrete thereinto. The raising and lowering of the bucket 51 may be controlled by a cable 53 which extends from operating means in crane 1 to pulley 55 at the base of the superstructure and up to and over pulleys 57 mounted on the superstructure.

The earth auger 27, which forms one of the novel features of our invention and is particularly useful in practising our method of forming concrete piles though not limited to earth drilling operations following the method of our invention, comprises the hollow stem or shaft 29, which is open at both ends and is designed for free and unobstructed flow of concrete therethrough. Fixed on and extending upwardly from the lower end of shaft 29 to a point spaced below the upper end of. the shaft are flights 59 which function to remove the excavated material as the auger is rotated by the air motor in a drilling operation. We have had satisfactory results when using a shaft of approximately 5 LD. and approximately A" plate flights at approximately 7 pitch. The edge of the lower flight 61 mounts a cutting plate 63 by means of bolts 65 and the cutting plate may be provided with a tapered leading edge 67 for cutting into the ground as the auger is rotated in a drilling operation.

We have used the numeral 69 to designate in its entirety the tip or hit of the earth auger. The tip 69 is mounted on the lower end of hollow shaft 29 by means of a collar 71 which encompasses the end of the shaft and is fixed thereto by welding or the like. The collar may be of split ring construction and if so the split should be welded after the collar 71 is mounted on the lower end of shaft 29.

Fixed in any suitable manner, as by welding, to the collar 71, we provide a pair of oppositely disposed and circumferentially spaced

elongated vanes

73 and 75, which depend downwardly from the collar. Each vane is inwardly curved or of arcuate formation downwardly to a point where the ends thereof are notched and abut as at 77, the extending ends 78 and 80 forming a fish tail point for the drill bit which breaks up any hard strata of material that may be encountered in the drilling operation. The abutting ends of the vanes may be fixed together by welding. The vanes are of downwardly tapering construction and the diameter of the lower end of the tip 69 is reduced relative to the diameter of the upper end. The forward or leading edge of vane is curved inwardly as at 76 while the forward or leading edge of vane 73 is curved inwardly as at 74'. The rear or pressure edge of vane 75 is curved outwardly as at 76 while the rear or pressure edge of vane 73 is curved outwardly as at 74.

A spreader plate 79 is welded to each of the vanes, the spreader plate extending between and in welded engagement with the vanes from a point adjacent the abut ting tips thereof upwardly a distance. This spreader plate, as will become apparent, functions as a structural member for the vanes and also as a spreader element for the concrete as it fiows out of the auger. Each vane is twisted or warped about a generally longitudinal axis and in the same direction from their fixed points on the collar to 5 thereby offset each longitudinal edge of one vane relative to the plane of rotation of one of the longitudinal edges of the other vane. This twisting distortion or warping of the vanes also causes the abutting ends of the vanes to be offset as at 81. Due to the warping of the

vanes

73 and 75, as described, the leading

edges

74 and 76 on the vanes, along substantially their entire lengths, are disposed radially inwardly relative to the trailing edges 74 and 76' of the vanes. Consideration, particularly of Figure 5 of the drawings, will clearly illustrate that, as the auger is rotated in a drilling operation in the direction of the arrow, the excavated material will be thrown radially outwardly due to the unique distortion configuration of the vanes, which relatively positions the leading and trailing edges, as described. Thus, no excavated material will be forced or will otherwise accumulate in and clog the shaft 29, through which concrete is adapted to flow.

In order to facilitate the drilling operation we provide a number of fins on each vane which extend radially outwardly therefrom. In the particular embodiment illustrated in the drawing we provide three fins 86 which may be welded to the vane 73 in vertically spaced relation. Each side fin is fixed to the vane at an angle or inclined downwardly in a forward direction so that its leading edge 88 is lower than its trailing edge 90. Three generally similar fins 92 are fixed on vane 75, the lowermost of said fins being fixed in a plane below the lowermost fin 86 on vane 74 and the other fins 92 being alternately positioned horizontally with respect to fins 86. The fins 92 are mounted at an angle so that each leading edge 94 is lower than each trailing edge 96. It will be recognized that due to this particular construction the

fins

86 and 92 will push the material up to the cutting edge 67 and onto the flights.

When it is desired to form poured-in-place concrete piles, in accordance with our method and with the apparatus we have devised, the superstructure 5 is posi.

tioned adjacent the site in which the hole is to be drilled, superstructure being so positioned that the sliding platform or elevator will be directly over the spot Where the hole is to be drilled. It will be understood, of course, that all of the operating equipment is properly mounted on the superstructure and operatively connected with the crane and compressor. The auger is then rotated by the air motor and the hole is drilled to the proper depth, whereupon the rotation of the auger is stopped and the auger is maintained in its position; within the hole which it has just drilled. With the auger in position within the drilled hole, it will be evident that it acts as a reinforcing or stabilizing member preventing collapse or cave-in of the walls of the hole. Thus, it is not necessary when following the teachings of our method to apply any additional stabilizing medium to the walls and we have therefore eliminated steps in prior art methods and we have also eliminated the need for extra equipment.

In designing the tip or bit of the auger, it was necessary to form all components of the tip so that they would not obstruct the concrete as it flows out of the hollow shaft and past and through the tip. It was essential, of course, not to sacrifice the cutting and operating characteristics of the tip in order to afford free unobstructed flow. With these prerequisites in mind, we also had to design the tip so that it would throw the excavated material radially outwardly, rather than inwardly, to thereby avoid clogging the shaft or the tip with excavated material which would hinder concrete flow. We have evolved a tip which accomplishes all of these purposes. It presents no obstructions against flow of concrete. It cuts efliciently and it throws the excavated material radially outwardly and upwardly where it is caught by the spiral flights 59 and carried upwardly out of the hole. As the drilling operation proceeds, the blade 63 cuts into the ground radially, outwardly of the hole cut by

vanes

73 and 75. Since the interior flow duct for concrete provided by shaft 29 is Smooth and presents no obstructions whatsoever against crete, as described, while using a 15 /2" diameter auger to dumped into the pressure pot 33. It is desirable that the charge of concrete be an amount which is predetermined and is suflicient to fill the hole with concrete 86 to a level, such as 87 (Fig. l), at which time the auger is fully withdrawn from the hole.

When the pressure pot has been loaded with the concrete and covered in any suitable manner, it may be subjected to a head of pressure from compressor 39 through hose 41 to force the contained concrete downward through tubular shaft 29 and out the lower end thereof and past the tip 69 and into the hole. As the concrete flows out of the shaft, it will not be obstructed or hindered by the tip for the reason that all components thereof, which are more or less in alignment with the interior of the shaft are spaced a distance from the outlet therefrom and the closest is the upper edge 89 of plate 79, which is relatively thin and a nonobstructive surface. Thus, the concrete will not clog up as it exhausts from the shaft outlet and may freely flow radially outwardly between the

vanes

73 and 75 and into the hole.

As the concrete is forced from the pressure pot through the shaft and out the tip or bit, the auger unit is withdrawn at a speed to keep the tip or hit below the surface of the deposited concrete. As the auger is withdrawn, it is not rotated and the spreader plate 79 serves to divide and spread the concrete flowing through the bit. The Withdrawal of the auger is of course operated from the crane by means of the hoist line 23.

When all of the concrete is emptied from the pressure pot into the hole, the concrete will have reached the level 87, leaving an unfilled upper section 91 in the hole. At this time, when the hole has been filled with concrete to the level 87, the auger is fully withdrawn and a cover may be placed over the hole and the waste excavated material on the spiral flights may be shaken loose. The cover is then removed from the hole and the auger is lowered back in. the hole to remove the top one foot of concrete, only if soil or other deleterious matter has fallen back into the hole on the concrete. If no such matter has fallen back into the hole, or, after it has been removed with the auger, then a reinforcing cage 93 is lowered into the unfilled portion of hole 91 and the hole filled with concrete in any conventional manner.

Merely as one example from among many of the dimensional characteristics which the auger may have, we have successfully drilled the holes and poured the conproduce a 16" hole, the ID. of the shaft 29 being 5". The overall length of the tip or hit being 13 /2, while the diameter of the lower end is approximately 5 /2" (shaft O.D.), while the diameter of the drag edge is 6% (OD. collar 71). The upper edge 89 of spreader plate 79 is approximately 4" below outlet of shaft 29.

It is to be understood that the mechanical equipment and operating means for positioning and controlling the auger may be changed and still fall within the spirit and scope of our invention for the rig and equipment illustrated in Figure l is included merely by Way of example and not as limiting our invention to use with the particular equipment disclosed for operating and controlling the earth auger.

It will now be recognized that we have devised a rapid and efficient method of forming poured-in-place concrete piles and also the equipment whereby the method may be carried out. Our method substantially reduces the time required to form piles of this character as well as 7 eliminating much equipment and materials formerly required.

We claim:

The method of forming poured-in-place concrete piles which comprises drilling a hole in the ground with a tubular auger open at its lower end and provided with a bit having openings therein and said auger being provided with spiral flights, forcing the excavated material radially outwardly relative to the bit during the drilling operation, maintaining the interior of the tubular auger free of earth during the drilling operation, drilling into the earth whereby a portion of the earth on the spiral flights is removed from the hole, maintaining the auger at the full depth of the hole at the conclusion of the drilling operation and, when the hole has been drilled to the proper depth, injecting concrete into the auger at a pressure only sufficient to cause flow of the concrete through the auger and past the bit into the hole while simultaneously applying vertical lifting forces to the upper end of the auger to gradually non-rotatively withdraw the auger and the remaining portion of the earth on the spiral flights from the hole.

References Cited in the fileof this patent UNITED STATES PATENTS Heath Mar. 31, 1868 Philips et a1 Feb. 12, 1884 Densmore Sept. 26, 1899 Shuman Feb. 23, 1904 McCormick Feb. 11, 1913 Tufts Nov. 8, 1921 Powell Jan. 3, 1928 Rea Mar. 21, 1933 Zerbe Apr. 3, 1934 Montee Dec. 10, 1935 Graham Dec. 22, 1942 Patterson Jan. 3, 1956 FOREIGN PATENTS Germany Dec. 28, 1882 Austria July 10, 1914 France Dec. 22, 1954