US3479829A

US3479829A - Method and apparatus for forming end bearing piles

Info

Publication number: US3479829A
Application number: US647818A
Authority: US
Inventors: Willard B Goodman
Original assignee: Shell Oil Co
Current assignee: Shell USA Inc
Priority date: 1967-06-21
Filing date: 1967-06-21
Publication date: 1969-11-25
Anticipated expiration: 1986-11-25

Description

AI/f/ FIG.

FIG. 5

FIG. 4

METHOD AND APPARATUS FOR FORMING END BEARING FILES Nov. 25, 1969 INVENTOR:

W. B. GOODMAN HIS ATTORNEY FIG.

FIG. 7

nited States Patent O 3,479,829 METHOD AND APPARATUS FOR FORMING END BEARING PILES Willard B. Goodman, Sherman Oaks, Calif., assignor to Shell Oil Company, New York, N.Y., a corporation of Delaware Filed June 21, 1967, Ser. No. 647,818 Int. Cl. E0211 /34, 5/54; Elli) 11/02 US. Cl. 6153.6 Claims ABSTRACT OF THE DISCLOSURE An elongated tubular member, having fins near one end and injection ports adjacent the fins, is sonically driven into an earth formation and rotated at a selected depth while a slurry of solidifiable material such as cement is injected into the formation from the ports forming an enlarged base. The tubular member is then withdrawn from the formation while cement is pumped through the member into the borehole to form the body of the pile.

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to the construction of piles, and pertains more particularly to the casting in-place of bulbular based end bearing piles.

Description of the Prior Art In the construction of buildings, bridges, piers and other similar structures, it is necessary to establish a foundation on which the structure must rest. Generally, this foundation is established by driving or establishing in an earth formation pilings on which the structure must rest. The load capacity of these piers, buildings, etc., depends on the load capacity of the piles. The load capacity of the piles depends on two basic factors. These factors are soil friction along the length of th pile and end-bearing resistance. Certain earth formations offer very little soil frictional resistance to the pile; therefore, the load capacity of the pile depends upon its end-bearing resistance. This endbearing resistance is generally directly related to the diameter of the pile. In low-friction soils it is the diameter of the base or lower end of the pile that determines its carrying capacity; therefore, it is not necessary that the upper portion or body of the pile have greater diameter than the lower portion. In fact, great savings in material may be achieved by making the base of the pile as large as possibl while constructing the body of the pile of a much smaller diameter. One commonly known pile of this character is the bulbular base pile. This pile has an enlarged base or foot. This bulbular base pile and the most common method of forming it are illustrated in US. Patent No. 1,764,948. In accordance with this method a specially constructed rig is moved to the construction site. A casing of heavy-gauge, high tensile alloy steel is raised in place. A portion of very dry concrete is then placed in the bottom of the casing to form a driving plug. Next, a heavy, solid ram weighing from two to four tons is lowered into the casing and raised and dropped to drive the plug into th ground which action pulls or carries the casing with it by means of friction between it and the casing. At the desired level the casing is then anchored to the rig and a plug driven out the bottom of the casing by th ram. More concrete is then dumped into the casing and rammed out the bottom to form the bulb. The casing is then raised small increments as more concrete is dumped into the casing and rammed out the bottom thereof to form the rest of the pile.

Among the disadvantages of the prior known methods of constructing such piles is that such methods are timeice consuming and therefore expensive. Furthermore, the apparatus used in such methods is heavy, complicated and cumbersome, which also adds to the cost of constructing such piles.

SUMMARY OF THE INVENTION It is the primary object of the present invention to overcome the above disadvantages by providing a method and apparatus that is rapid and efiicient for the construction in place of high load capacity end bearing piles.

It is a further object of the present invention to provide a method for the forming in place of high load capacity piles, which method is simple, easy to use and rapid in operation.

It is still a further object of the present invention to provide a method and apparatus for the forming in place of bulbular base piles that takes maximum advantage of the capacities of the various strata in an earth formation.

BRIEF DESCRIPTION OF THE DRAWING These and other objects and advantages will become apparent from the following description when read in connection with the accompanying drawings in which:

FIGURE 1 is an elevational view showing somewhat schematically a preferred embodiment of a suitable apparatus for carrying out the present invention;

FIGURES 2-4 are detailed views, partly in section, of a preferred embodiment of the tool of the present invention;

FIGURE 5 is a section through a second embodiment of the invention;

FIGURE 6 is a view of a third embodiment of the apparatus of the present invention; and

FIGURES 7 and 8 illustrate a fourth embodiment of the apparatus 10 of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to the drawings, a preferred embodiment of the apparatus of the present invention is illustrated in FIGURES 14. The apparatus as shown in FIGURE 1 comprises support structure, preferably portable, i.e., mounted on a vehicle (not shown). The apparatus illustrated in FIGURE 1 comprises a base member 11 having attached thereto and extending upward therefrom a pair of

upright members

12 and 13, connected together by means of a pair of cross members 14 and 15. Attached to the upright members and extending upward or somewhat vertically is a pair of guide members or

rails

16 and 17 on which is slidably mounted a driving head 18. The driving head may be of any suitable type such as a ram or drop hammer; however, a sonic vibratory driving head is preferred. A suitable sonic driving head is shown in US. Patent No. 2,975,846 to which patent reference is also made for an understanding of the sonic method of driving. Attached to the upper portion of driving head 18 is a flexible member or cable 19 extending over sheave 20 to a suitable power source (not shown) for raising and lowering the driving head. Extending downward from the driving head 18 is a driving mandrel 21 which is connected by means of a flow mandrel 22 and a swivel coupling 23 to a bore-forming tool 24. The bore-forming tool extends downward through a conventional type rotary tabl 25 which is driven by a suitable power source or prime mover 26. The rotary table 25 has suitable means thereon for gripping the bore-forming tool member so as to rotate it. The bore-forming tool 24 has extending radially from the body near the lower or driven end thereof fins or vane-like members 27 and 28, for displacing a portion of the earth at or near the bottom of the borehole. The flow mandrel 22 has attached thereto a flexible line or conduit 31 leading from a pump 32 or other suitabl source of pressurized solidifiable fluid material.

With particular reference to FIGURES 1-4, the bore forming and material injecting tool comprises an elongated generally tubular elastic member 24 having a number of vanes or fin-like members 27 and 28 extending generally along the axis and radially outward beyond the outer surface of said elongated member. These vanes or fin-like members may be attached in any suitable manner such as welding, brazing or riveting to the tubular member 24. The lower or driven end, hereinafter referred to as the lower end of the tubular member, is closed by means of a removable plug or closure member 29. A port or opening 30 is provided to communicate from the interior of the tubular member to the extension thereof to a point preferably within the longitudinal dimensions of the vanes or fin-like members. This port or opening is illustrated as being adjacent one of the vanes, although it is understood that it may be located at any point between the vane members. In the preferred embodiment the port is located adjacent the vane so that the fluid material may be injected either ahead or behind the vane, depending upon the direction of rotation of the tubular member. However, in most soil conditions best results may be obtained when tubular member 24 is rotated in a counterclockwise direction as shown by arrows in FIG- URES 46 so that material is injected behind the vane. It is also unnecessary that the fins or vanes be of the shape illustrated. For example, they may be rectangular or triangular. The shape of the vanes will in general depend upon soil conditions and the type of load to be carried by the pile.

FIGURE illustrates an embodiment of the boreforming tool in which the injection ports 33 and 34 are illustrated as coming out through the fins. This embodiment may be more desirable in certain soil conditions, such as an incompetent soil.

Referring to FIGURE 6, an alternate embodiment of the

fins

35 and 36 is shown in which they are shaped with one surface sloping backward so that in one direction of rotation (counterclockwise as shown by the arrow) the soil is forced outward into the earth formation. Injection ports 35a and 36a permit injection of material into the cavity just behind

fins

35 and 36. However, these fins are shaped such that injection may be through holes (not shown) in tubular member 24 just ahead of the fins.

Still another form of the fins may be as illustrated in FIGURES 7 and 8, in which a pair of

fins

37, 38 are pivotally mounted on

pins

39 and 40 and are extendable outward through slots or

openings

41 and 42 in the tubular member. In this embodiment, the fins are extended or forced outward by means of a cam member or block 43 which is forced between the fins to extend them outward. This cam block or member has a central bore or passageway 44 therethrough to permit a fiuid material to pass through. Also in this embodiment the injection port function may be served by the slots through which the fins project, or they may be formed by a semi-circular slot (not shown) at one or both sides of the fins.

Although the fins are shown as being mounted on the tubular member, it is not necessary that they be so mounted. For example, they may be mounted on a separate tool that is inserted through the bore of the tubular member and extended out the slots of the member, or they may extend below the end of the tubular member.

OPERATION In operation, a borehole forming tool 24 with the desired shaped vanes 28, 27 is selected and coupled to the driving head 18. The lower end of the tool is closed by means of a cap member 29, and the tool is then sonically driven to the desired depth in the earth formation. The tool is then rotated by rotary table 25 while being vibrated to create, by the action of the vanes, a low-density area in the formation at a selected depth or level for receiving a solidifiable fluid material. A slurry of solidifiable material such as cement or concrete is then pumped through the bore of the tool member and injected through ports 30 into the low density area. This material may be injected while the tool is being rotated or afterwards, depending upon soil conditions and other factors. The material may also be mixed with the soil by continued rotation of the tool member, as may be desirable in a sandy type soil. In some soils the soil may be forced back into the formation to create a void which is then filled with the material. Preferably the tool is continuously vibrated sonically during rotation. The continued sonic vibration of the tool member lessens the friction of the soil on the shaft of the tool and thereby lessens the torque necessary to rotate the tool. When the bulb is completely formed as desired, the tool is then lifted or hoisted slowly out of the borehole and a slurry of the material is continuously fed into the bore of the tool, forcing the plug member off the end of the tool and filling the hole as the tool is removed. Preferably the tool is continuously sonically vibrated during this period of withdrawal. This continued vibration compacts the material and also facilitates the withdrawal of said tool member.

It can be readily seen that the present invention makes it possible to take advantage of different load carrying capacities of different strata in the earth formation by permitting one to place the base or other bulbs of the pile in or just above a high load capacity layer of soil. The most desirable position in the soil for the base of the pile may be established by any suitable means such as prior core samples.

It may also be appreciated that the tubular member 24 itself may be left in place as a pile or as reinforcing for the pile. If it is desirable to leave this tubular member in place, the member is rotated and sufficient cement or other solidifiable material injected into the formation to form the bulbular base and then the member is uncoupled from the driving head and left in place.

It may also be appreciated that any number of bulbs or enlarged portions may be formed along the length of the pile. This is accomplished preferably by forming the lowermost bulb first and then Withdrawing the tool to the desired level and forming a second bulb and so on until the desired number of bulbs are formed.

It can be easily seen that the tool 24 may be more easily withdrawn from the borehole when the fins 27 and 28 are aligned with the slots made while the tool was being driven. In this case they then do not have to create new grooves while the tool is being withdrawn. Thus, alignment may be accomplished by placing a mark on the tool member and one on the support or other structure. These marks are then aligned when the tool is being driven and again when it is being withdrawn.

The present invention is by no means intended to be limited by the foregoing illustrative embodiments, as it can be readily seen that various changes may be made in the invention without departing from the intended spirit and scope of the invention as defined by the appended claims.

I claim: 1. A method of forming a composition pile in situ within an earth formation, said method comprising the steps of:

forcing an elongated tubular member of closed lower end to the desired depth in an earth formation;

providing said tubular member with substantially vertically extending vane means projecting outwardly beyond the outer surface and near the lowermost portion of said elongated tubular member;

providing said tubular member with port means near the lowermost portion thereof and said vane means;

rotating said tubular member and said vane means to thereby create a material receiving area in said formation by the action of said vane means on said formation; and

injecting a fiowable slurry of solidifiable material from said port into said material receiving area.

2. The method of claim 1 wherein at least a portion of the steps of rotating said member and injecting said slurry into said area are carried on simultaneously.

3. The method of claim 2 further including the step of vibrating said tubular member during at least said rotating step.

4. The method of claim 3 further including the step of:

opening the lower end of said tubular member;

Withdrawing said tubular member from said earth formation; and forcing said slurry of solidifiable material out the opening in the lower end of said tubular member.

5. The method of claim 4 wherein:

said steps of forcing said member into said formation and withdrawing said member are carriedout sonically by means of a sonic pile driving apparatus.

6. The method of claim 2 wherein:

the step of injecting said slurry is carried out where discharge is ahead of said vane meanswhen considering direction of rotation of said member.

7. The method of claim 2 wherein:

the step of injecting said slurry is carried out where discharge is behind said vane means when considering direction of rotation of said member.

8. The method of claim 2 including:

vibrating said elongated member sonically during at least said forcing and said rotating steps.

9. The method of claim 2 wherein:

the step of forcing said tubular member into said earth formation is carried out sonically.

10. The method of claim 7 including:

vibrating said elongated member sonically during at least said rotating step.

11. In a method of forming bulbular base pile in an earth formation the steps of:

inserting an elongated tubular member into said earth formation;

providing a substantially vertically extending and outward directing material area generating means extending beyond the outer surface of said tubular member;

rotating said tubular member in said earth formation at a fixed predetermined level to form a material receiving area of enlarged diameter;

said area generating means forcing at least a portion of the earth from said area into said formation during said rotation; and,

injecting into said area during said rotation a flowable slurry of solidifiable material.

12. The method of claim 11 wherein:

the step of injecting said slurry is carried out where discharge is ahead of said area forming means when considering direction of rotation of said member.

13. The method of claim 11 wherein:

the step of injecting said slurry is carried out where discharge is behind said area forming means When considering direction of rotation of said member.

14. The method of claim 11 including the further step mixing said solidifiable material with earth material in said cavity by continued rotation of said tubular member.

15. An apparatus for use in the formation in situ of a high load bearing pile comprising:

UNITED STATES PATENTS References Cited 2,947,149 8/1960 Barkley 6153 2,942,426 6/1960 Stoll 61-53 3,270,511 9/1966 Colle 6l53.64 X 3,324,665 6/1967 Robichaux 6153.68 3,354,657 11/1967 Turzillo 6l53.52 3,391,543 7/1968 Sweeney et al. 6153.64

FOREIGN PATENTS 5/1941 Germany. 1/1962 Great Britain.

JACOB SHAPIRO, Primary Examiner U.S. Cl. X.R.