US3507124A - Method for making concrete piles - Google Patents

Description

April 21, 1970 L. A. TURZ ILLO l 3,507,124

. METHOD FOR MAKING CONCRETE PYILES Original File l Sept. 19, I969 v 2 Sheets-Sheet 1 FIG. I g

INVENTOR. Lee A. Turzillo At torneg A ril 21, 1970 ,L. 'A.' TURZILLO 3, 07, 2

mmnon FOfiMAKING CONCRETE FILES- Original Filed Sept. 19, 1969 2 Sheets-Sheet 2 FIG. 3

Attorney 3,507,124 METHOD FOR MAKING CONCRETE PILES Lee A. Turzillo, Bath, Ohio (2078 Glengary Road, Akron, Ohio 44313) Original application Sept. 19, 1967, Ser. No. 668,920. Divided and this application May 6, 1969, Ser. No.

Int. Cl. E02d /36; G01n 3/08 US. Cl. 61-53.64

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 force 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.

This is a divisional application of US. application Ser. No. 668,920 filed Sept. 19, 1967, Patent 3,434,653.

BACKGROUND OF INVENTION 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 object, 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 determining loads required.

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

nited States Pate 0 8 Claims 3,507,124 Patented Apr. 21, 1970 Of the accompanying drawings:

FIGURE 1 is a vertical cross-section, 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 testing-load 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 retracted 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 1811 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 1812 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 pointbearing 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 pointbearing 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 referred 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 is shown extended through a packing gland 24, mounted on the carriage 13, an integral extension 18a of shaft 18 having afiixed thereon a plunger 26 reciprocably received within a fluid-pressure operated jacking ram 27 on the carriage 13. Pressurized fluid, such as oil fro-m 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 sufiicient 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 pilebearing 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 com pressive strength test described in connection with FIG- UGES 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 or impact 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 one-half 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 given number of tons, for example, the drilling equipment 10 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 p.s.i. 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.) X 200+2000=11.3

tons. Should this capacity for a twelve-inch pile be insufiicient 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 earth-shearing 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 fluidsealing 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 augered 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 tensionbearing capacities, without the usual guesswork of prior procedures which often resulted in piles being of greater depth 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 susbtantially fool-proof step for selectively determining the allowable pile-bearing 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 Patent No. 3,426,538, issued Feb. 11, 1969.

What is claimed is:

1. A method of forming piles of requisite load capacity in an earth situs, comprising the steps of: driving a drilling tool into the earth of the situs, progressively to define a pile cavity of selective depth, applying ramming power to an earth-testing member relatively movably located at the inner end of the tool to impact a given area of the member against a like area of foundation earth at the inner end wall of the cavity of selected depth with force related to the ramming power and measurable in terms of load capacities of the situs; and forcing fluid hydraulic cement grout under pressure into said defined cavity when it is of a sufiicient depth that the force measured by pressure of the member against the foundation earth substantially corresponds to at least that required for said requisite load capacity.

2. A method as in claim 1, wherein said grout is progressively forced through said tool into the cavity space below the same as the tool is removed from the cavity.

3. A method of forming a pile of requisite load capacity in an earth situs, comprising the steps of: rotating a hollow-shafted auger drill into the earth, progressively to define a pile cavity of selective depth; applying ramming power to an earth-testing member relatively movably located at the inner end of the drill shaft to impact a given area of the member against a like given area of the foundation earth at the inner end wall of the caivty of selected depth with force related to the ramming power and measurable in terms of load capacities per unit area of foundation earth so compacted; and forcing fluid, self-hardenable cementitious material under pressure into said defined cavity, when it is of a sufficient depth that said measurable impacting force substantially corresponds to at least said requisite load capacity.

4. A method as in claim 3, wherein said cementitious material is progressively forced through a passageway in the drill to the cavity space below the drill as the drill is progressively removed from the cavity.

5. A method as inclaim 3, said earth-testing member having an earth-engaging face of predetermined area;

said ramming power being applied by a hydraulic jacking ram, the impacting force of which is readable on a gauge in pressure units per given area units, which when translated to corresponding area units of the finished formed pile gives the load-carrying capacity of the pile.

6. A method providing a pile cavity in an earth situs, comprising the steps of: driving a drilling tool into the earth situs progressively to define a pile or like cavity of selective depth; applying ramming power to an earth-testing member relatively movably mounted on the inner end of said tool to impact a given area of the member against a like area of foundation earth and the inner end wall of the cavity of selected depth with force related to the ramming power and measurable in terms of load capacity per given unit of area impacted by the member; and terminating said drilling of the earth at the requisite selective depth indicated by the measured force resisted by the impacted foundation earth.

7. A method as in claim 6, including the step of applying sufiicient said impacting force to the earth-testing member to measure the shear resistance of said impacted foundation earth.

8. A method as in claim 1, including the step of applying suflicient said force to the earth-testing member to measure the shear resistance of said impacted foundation earth.

References Cited UNITED STATES PATENTS 1,979,547 11/1934 Hood 61--53.64 3,200,599 8/1965 Phares et al 61'53.64

FOREIGN PATENTS 132,536 7/1929 Switzerland.

JACOB SHAPIRO, Primary Examiner US. Cl. X.R 73-12 UNITED STATES PATENT OFFICE- CERTIFICATE OF CORRECTION Patent No. 3,507,124

Lee A. Turzillo It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

April 21, 1970 Column 1, line 24, "3,434,653" should read 3,470,701

Signed and sealed this 12th day of January 1971.

(SEAL) Attest:

WILLIAM E; SCHUYLER, JR.

Edward M. Fletcher, Ir.

Commissioner of Patents Attesting Officer

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