US3470701A

US3470701A - Means for making concrete piles

Info

Publication number: US3470701A
Application number: US668920A
Authority: US
Inventors: Lee A Turzillo
Original assignee: Individual
Current assignee: Individual
Priority date: 1967-09-19
Filing date: 1967-09-19
Publication date: 1969-10-07
Anticipated expiration: 1986-10-07

Description

7. 1969 L. A. TURZILLO 3,470,701

MEANS FOR MAKING CONCRETE FILES Filed Sept. 19, 1967 2 Sheets-Sheet l /l4a G k 5 fi" EMF-* 39 fi P1711113 I 7 la X xw mm INVENTOR. Lee A. Turzillo uiaa'emfauzuuj At torneq Oct. 7, 1969 TURZILLO 3,470,701

MEANS FOR MAKING CONCRETE FILES Filed Sept. 1.9, 1967 2 Sheets-Sheet TE FIG.3

United States Patent O 3,470,701 MEANS FOR MAKING CONCRETE PILES Lee A. Turzillo, Bath, Ohio (2078 Glengary Road, Akron, Ohio 44313) Filed Sept. 19, 1967, Ser. No. 668,920

Int. Cl. E0211 /36 U.S. Cl. til-63 12 Claims ABSTRACT OF THE DISCLOSURE Pile cavity of given diameter drilled in earth situs to selective depth, determined by load capacity, compressive strength tests of earth at inner end of cavity; Extension of testing member with manifested forced at selective depth used to determine allowable pile bearing load. Pile body made by pumping pressurized fluid cement grout into cavity has load capacity corresponding to earthresisting tests for selective depths.

BACKGROUND OF INVENTION Heretofore, concrete piles have been formed in situ by various methods, generally employing spiral-fiighted auger drills to provide cavities of estimated depths which were filled with self-hardening concrete. In use of known methods, however, the load and tension-bearing capacities of the piles could be determined only after they had been formed and hardened in the situs and load tested. Load capacities, therefore, were roughly estimated in advance and concrete piles were often formed to depths substantially greater than necessary as a factor of safety, and to allow for substantial variations in soil consistency.

SUMMARY OF INVENTION In practice of the present invention to form a pile of requisite load capacity for a particular earth situs, a hollow-shafted auger drill is rotated in the earth situs to define a pile cavity of selective depth, determined by relatively moving a load-testing head with respect to the drill shaft to urge a portion thereof against a given area of foundation earth at the inner end wall of the pile cavity. The testing force required is measurable on a pressure gauge in terms of load capacities per unit area of the soil contacted by the testing head. When the depth of cavity is reached at which the load capacity is suitable for the particular diameter of the pile to be installed, as indicated on the pressure gauge possibly with the aid of prepared charts or other means, the auger drill is removed to replace the soil in the cavity with pressurized, fluid hydraulic cement grout, to have upon hardening the requisite load and tension-bearing capacities for the particular soil of the situs.

One object of the present invention is to provide a novel method and means for forming concrete piles in an earth situs by which the depth and/or size of the pile for requisite load capacities for a given situs can be selectively predetermined prior to supplying the fluid cement grout to the pile cavity.

Another object of the invention is to provide a method and means as described in the preceding objects, by which is eliminated the usual procedure of over-estimating load requirements of the piles and of making unusable test piles in the situs for determined loads required.

Other objects of the invention will be manifest from the following brief description and the accompanying drawings. 0f the accompanying drawings:

FIGURE 1 is a vertical cross-sectiona, partly broken away, illustrating an initial stage of use of auger-drilling equipment for providing a pile cavity in an earth situs in accordance with the method of the invention.

FIGURE 2 is an enlarged horizontal cross-section, taken substantially on the line 2--2 of FIGURE 1.

FIGURE 3 is an enlarged, fragmentary, vertical crosssection, corresponding to the lower portion of FIGURE 1, but enlarged and broken away to illustrate the lost motion connection of the driving bit of the auger drill, and the improved method and means for the testingload capacities possible at selective cavity depths.

FIGURE 4 is a fragmentary cross-section, corresponding to FIGURE 3, but illustrating operation of a pile-load testing head of the invention.

FIGURE 5 is a view corresponding to FIGURE 3, but illustrating the driving bit and auger in position for progressively pumping grout into the augered pile cavity.

FIGURE 6 is a vertical cross-section on the same scale as FIGURE 1, illustrating the completed concrete pile formed in the pile cavity in accordance with the method of the invention.

Referring particularly to FIGURES 1, 2, and 3, there is illustrated apparatus 10 for drilling a pile cavity 11 in an earth situs E, and which may include a sectional, continuous-flight, hollow-shafted auger drill 12 rotatably mounted on a conventional carriage 13 which is vertically movable on guide rails 14a of an upright 14, as by means of a power-activated hoist cable 15 attached to said carriage. A reversible hydraulic motor 16, mounted on carriage 13 is operable to rotate the auger drill 12 in clockwise direction about a vertical axis, as by means of a chain drive 17, to penetrate the earth situs E to requisite depth.

A hollow ramming shaft 18 may be reciprocably received centrally through the auger shaft 19, including a fluid-sealing packing gland 19a at the lower end thereof, and similar packing gland at the upper end of the auger shaft 18 otherwise being suitably keyed to rotate with the auger.

By means to be described later, the ramming shaft 18 is in use generally as shown in FIGURES 1 to 3, normally retained in upwardly retract-ed condition with respect to the auger, to retain the upper end face 20a of bit 20 in complementally seated abutment against the closed lower end of the auger shaft 19. For this purpose, the cylindrical lower end 18a of ramming shaft 18, protruding from the auger shaft, serves as an earth testing head which is axially slidably received for lost motion axial movement within a cylindrical passage 20b in the bit head 22. To this end one or more keys 18b may be affixed on testing head 18a for limited axial movement along slots 22b provided in passage 20b to retain the bit 20 in the fully retracted position of the same and the head 18a, as shown in FIGURE 3. In this retracted condition, a terminal end 21 of testing head 18a constitutes a point-bearing face which is substantially flush with the inner end of the tapered head 22 (see FIGURES 1 and 3). In other words, the point-bearing face 21 of the testing head 18a normally is considered to be the innermost end wall of head 22. When, however, the shaft 18 is downwardly extended with respect to the auger shaft 19, as shown in FIGURE 5, the head 22 is free to have said lost motion connection with the solid testing head 18a of shaft 18, as limited by stop engagement of the keys 18b between the opposite ends of the slots 22b. Thus, starting with the retracted condition of the related parts shown in FIGURE 3, in which the tapered head 22 is illustrated as being supported by the augered earth A at the bottom of a pile cavity, the testing head 18a of the ramming shaft 18 may have requisite downward force applied thereto by ram 27 to apply point-bearing load to a corresponding area of foundation earth of the inner end wall of the pile cavity. For this purpose, it may be said that the point-bearing load ref-erred to above is the maximum load that can be applied by the face 21 of the testing head 18a against the foundation earth, without substantial movement of the foundation earth, as indicated by a pressure gauge G in operating means to be further described (see FIGURE 1).

The outer end of the ramming shaft 18 i shown extended through a packing gland 24, mounted on the carn'age 13, an integral extension 18a of shaft 18 having affixed thereon a plunger 26 reciprocably received within a fluid-pressure operated jacking ram 27 on the carriage 13. Pressurized fluid, such as oil from a suitable source (not shown) may be supplied through a conduit means 30a and 30b, in which is provided a four-way control valve 38 and an adjustable pressure control valve 39, to operate the plunger 26 and apply powerful ramming force to the ramming shaft 18, and thereby to urge the driving bit 22 against the foundation earth of the inner cavity wall 11a, with requisite compressive force indicated on a pressure gauge G in the conduit means 30a. In other words, before any substantial movement of the foundation earth starts, as readable on a suitable linear movement gauge on the carriage 13, and a pointer on shaft 18, pressure readings on the pressure gauge G are related to the given area of the bearing face 21 on testing head 18a, such as in pounds per square inch, to determine when the cavity 11 is of sufficient depth selectively to stop further drilling and to contain a concrete pile therein which will support a load in accordance with predetermined requirements thereof.

For supplying pressurized hydraulic cement grout from a supply thereof, not shown, to a pile cavity 11 of selective depth, one or more apertures 36 may be provided in the lower end of the hollow ramming shaft 18, to be above, or closed by, the lower packing gland 19a of the auger drill, but to be exposed within a space between the lower end of the auger drill and the driving bit head 22 in an extended position of the ramming shaft, as shown in FIGURE 5, for example.

As will be self-evident later, the above-described structure also makes it possible to determine the allowable pile-bearing load for any selective pile cavity depth before concrete material is pumped into the same. In other words, when a cavity depth is reached at which the compressive strength test described in connection with FIG- URES 1 and 3 is satisfactory, the ramming shaft 18 is downwardly operable to push the testing head 18a outwardly of the driving bit 20, and to compress the foundation soil to a point of failure, as shown in FIGURE 4, the force required for this being readable on gauge G, while the extent of the earth movement is visible on linear measurement gauge L.

This reading for the compressive strength may be utilized to determine the shear strength at this cavity depth by applying the formula that the shear strength is onehalf the compressive strength. Shear strengths will be determined for each type of soil encountered by the test described in connection with FIGURES 1 and 3 and the formula stated above. The total allowable .pile load in skin friction for a given pile length can be determined by multiplying the allowable shear strength by the perimeter of the cavity and the thickness of the layer of the particular type of soil. The total allowable pile bearing load of a given pile can be determined by adding the skin friction capacity for the various types of soil encountered in the cavity plus the end bearing value obtained by multiplying the unit bearing value per square inch obtained from the gauge marked (G) by the area of the bottom of the cavity.

In use of the equipment shown in FIGURE 1 to form a pile 12 inches in diameter to support a load of a given number of tons, for example, the drilling equipment positioned at the situs is adjusted and operated to turn the auger drill 12 vertically into the earth E of the situs. Rotation of the drill is stopped when a cavity of an approximate required depth has been defined. Next, while holding the auger drill stationary, the jacking-ram 27 is operated by selectively supplying pressurized oil thereto through the conduit means 30a, 30b to urge the jacking shaft downwardly to a visible extent, if any, with substantial force, thereby to urge the pressure head 22 against the foundation earth of the inner end wall 11a of the defined cavity. If the pressure, as indicated on the gauge G shows that the compressive value of the soil is deficient in load-carrying capacity at a point where movement of the foundation earth begins, the drilling and testing operations are repeated as necessary until suitable soil conditions are reached. As an example, if the gauge reading for a selected depth of cavity is 200 psi. at the point of movement of the initial compression value of the foundation earth would be 200 p.s.i., so that the load-carrying capacity of a 12-inch diameter concrete pile, With an area of 113 sq. in. would be 113 (sq. in.) 200+2000'=ll.3 tons. Should this capacity for a twelve-inch pile be insufficient for a particular purpose, the aforesaid drilling and testing is repeated. On the other hand, should it be determined that a 11.3 ton point-bearing load capacity is sufficient, it is now possible to determine the total allowable pile-bearing load of any pile by use of a known formula based on the shearing test described above in connection with FIGURE 4. The data obtained by the earthshearing test, therefore, can be used to determine the diameter and length of piles needed to support given loads, before any concrete is pumped into the pile cavities.

Accordingly, after determination of the requisite depth of the pile cavity as described, and with the ramming shaft 18 extended in the full impacting position of impacting head 22, as shown in FIGURE 5, fluid hydraulic cement grout may be pumped into the bottom of the cavity 11 through grout supply conduit 35 and a fluid-sealing coupling on ramming shaft 18, the ramming shaft itself and through normally closed by-pass opening means 36 at the lower end of shaft 18 and into the bottom of cavity 11, all while the auger shaft 12 (including the driving bit 22) is progressively withdrawn from the cavity 11 while removing the angered earth with it, until the entire cavity is filled with grout. FIGURE 6 shows the fully formed and hardened, concrete pile body P of selective depth and requisite load and tension-bearing capacity provided in the situs.

The method and means described above makes it possible to form piles of varying selective depths and diameters for the same or different requisite load and tension-bearing capacities, without the usual guesswork of prior procedures which often resulted in piles being of greater depths and load capacities than necessary, with resultant extra costs for material and labor. The method also eliminates the necessity for producing additional piles when tests show that installed piles are inadequate. Moreover, as the present method includes a substantially foolproof step for selectively determining the allowable pilebearing loads of the piles under construction, regardless of variations in soil conditions of the situs, neither preliminary nor subsequent costly load capacity tests are necessary.

It is readily apparent that the above described method and means generally may be varied considerably without departing from the spirit of the invention or the scope of the appended claims. As an example, the method may employ procedures disclosed in applicants copending patent application Ser. No. 658,107 filed Aug. 3, 1967, for forming the pile cavity and supplying pressurized grout thereto. It would also be possible to employ the present selective pile depth method with use of the apparatus disclosed in applicants pending application Ser. No. 441,053, filed Mar. 19, 1965.

What is claimed is:

1. Apparatus for forming a pile of requisite load capacity in an earth situs, comprising: boring means for drilling a cavity of selective depth in the situs; a ramming shaft reciprocably mounted through said boring means and having a testing member on the inner end thereof provided with an inwardly exposed pressurizing face of given area; power means for axially forcibly moving said testing member relatively of the boring means within the cavity to force said member against a Corresponding area of foundation earth at the inner end of the cavity at selective depths thereof; means related to force applied by said power means to said testing member for manifesting said force of said member against said corresponding area of foundation earth; and means related to force applied by said power means to said testing member for supplying fluid hydraulic cement grout through said boring means to fill the cavity of a said selective depth to have upon hardening a requisite load capacity indicated by the manifesting means.

2. Apparatus as in claim 1, said boring means including a hollow-shafted spiral flight auger, and said ramming shaft being reciprocably keyed within the auger shaft.

3. Apparatus as in claim 2, said member including a driving bit to facilitate drilling the cavity.

4. Apparatus as in claim 2, said member having passage means therein, and said means for supplying, including a conduit within said auger shaft connecting a source of fluid hydraulic cement with said passage means to the drilled cavity.

5. Apparatus as in claim 4, said driving bit being on the inner end of said ramming shaft for limited axial movement thereon relatively of ramming shaft; said member comprising an end portion on said ramming shaft axially shiftable through said driving bit, and said pressurizing face being on the inwardly presented end of said end portion.

6. Apparatus as in claim 5, said ramming shaft having a passage therethrough to said end portion for outward passage of grout when said ramming shaft is axially shifted for movement of the driving bit relatively of the ramming shaft.

7. Apparatus for forming a pile of requisite load capacity in an earth situs, comprising: boring means for drilling a cavity of selective depth in the situs; a ramming shaft reciprocably mounted through said boring means and having a testing member on the inner end thereof provided with an inwardly exposed pressurizing face of given area; power means for axially forcibly moving said testing member relatively of the boring means within the cavity to force said member against a corresponding area of foundation earth at the inner end of the cavity at selective depths thereof; means related to force applied by said power means to said testing member for manifesting said force of said member against said corresponding area of foundation earth; and means related to force applied by said power means to said testing member for supplying fluid hydraulic cement grout through said boring means to fill the cavity of a said selective depth to have upon hardening a requisite load capacity indicated by the manifesting means, said boring means having a driving bit at the inner end thereof mounted on said ramming shaft for limited axial, lost-motion movement thereon, said testing member comprising the inner end of said ramming shaft terminating in said pressurizing face.

8. Apparatus as in claim 7, said driving bit normally being retracted toward the inner end of said boring means in correspondingly retracted condition of said ramming shaft with respect to the boring means, said testing member likewise normally being retracted within said driving bit, and being operable outwardly thereof against said area of foundation earth by extension of said ramming shaft with respect to the boring means.

9. Apparatus as in claim 8, said ramming shaft having passage means therethrough for supplying said grout to the cavity when said ramming shaft is extended to move said driving bit inwardly of said boring means.

10. Apparatus as in claim 9, complemental means being provided on said driving bit and said ramming shaft for locking the same against relative rotation in said retracted condition of the driving bit.

11. Apparatus as in claim 7, complemental means being provided on said driving bit and said ramming shaft for locking the same against relative rotation in said retracted condition of the driving bit.

12. Apparatus as in claim 8, means being provided for gauging said forcible movement of said testing member relatively of said boring means.

References Cited UNITED STATES PATENTS 1,979,547 11/1934 Hood 6153.64 2,952,131 9/1960 Lyroudias 6163 3,200,599 8/1965 Phares et al 61-5364 3,300,988 1/1967 Phares et a1. 61-63 JACOB SHAPIRO, Primary Examiner U.S. Cl. X.R.