US 3289421 A
Description (OCR text may contain errors)
ec., 69 E966 R. G. HINDMAN yggm METHOD FOR DRIVING' PILES Filed March 18, 1964 2 SheetS-Sheeb l FIG. vI.
-DRIVING HEAD FILL-UP LINE f E ig ELECTRICAL LEAD To PUMP ADJUSTABLE PLATFORM DRIVEN PILE f-INVHAL SECTION Mun LINE Dec. 6, 1166 R. G. Hmm/AN METHOD FOR DRIVING PILES 2 Sheets-Sheet 2 Filed March 18, 1964 DRIVING K V HEAD g/ INVENTOR.
CENTRALIZER of qlc.;
W j f l M., XJ
r VULLXL* United States Patent O 3,289,421 METHOD FOR DRIVING PILES Robert G. Hindman, New Orleans, La., assgnor, by mesue assignments, to Esso Production Research Company, Houston, Tex., a corporation of Delaware Filed Mar. 18, 1964, Ser. No. 352,922 8 Claims. (Cl. 6153.74)
The present invention generally concerns the construction of drilling platforms and particularly, the manner of forming foundations for such drilling platforms.
In driving piles, especially those to be used to carry offshore drilling structures, by ordinary hammer means adequate pile penetrations cannot be achieved in dense sands because of the great buildup ofend bearing on the piles in the sand formation. Pile driving in such sands often results in premature refusal, particularly for tension or holddown requirements.
The invention to be described herein overcomes the disadvantages inherent in ordinary pile driving techniques and achieves deep penetrations of piles into dense sand formations with a minimum of pile driving difliculty.
In accordance with the invention, pilings such as steel tubings -or cylinders are driven with a hammer in a conventional way while simultaneously jettng water into the sand into which the piling is driven to reduce the resistance to pile penetration. A pump is used to drive and force the water into the sand while new sections of pile are being added, as Well as when the pile sections are being driven into the sand.
A primary object of the invention is to provide an improved method and apparatus for driving piles into dense sands utilizing a water-jet line yfor jetting water into the sands that is capable of continuous operation.
The above and other objects and advantages of the invention will be apparent from the following, more detailed description thereof when taken with the drawings in which:
FIG. 1 is a side elevation partially in section of apparatus embodying the invention and illustrating driving of the piles;
FIG. 2 is an elevational view of the jet-line assembly (and the pump) of the present invention;
FIGS. 3 and 4 are side elevations partly in section of a pile to be driven into the underlying sand and illustrating positioning of the jet-line assembly and its action in accordance with the method of the invention; and
FIG. 4A is a side elevation of the upper end of FIG. 4 illustrating the driving head and anvil welded to the pile sections.
In the drawings, FIG. l shows a barge on which is mounted a platform 11 and a crane 12 from which is suspended a steam hammer 13 used to drive piles 14 into the dense sand formation below the less dense sand or mud zone 16. Barge 10 oats on water 17. One pile has peen driven through to refusal and the other pile consisting of an initial pile section 14a and an upper, new pile section 14b is shown in position to be driven into sand formation 15 by means of a driving head 18 on which is mounted steam hammer 13. The sections of piling are welded together and to driving head 18 as indicated at 19.
FIGS. 3 and 4 show pile section 14a in position for penetration into sand formation 15. In FIG. 3 a jet-line pump assembly 20 is shown being washed downwardly through zone 16 in pile section 14a. Assembly 20, as shown more clearly in FIG. 2, includes a tubular member 21 provided with an inverted submersible pump 22 at its upper end and perforations 23 adjacent its lower end. Tubular member 21 is provided with centralizer springs or arms 21a. An inlet screen 24 is provided on the suc- 3,289,421 Patented Dec. 6, 1966 tion end of pump 22. A high pressure pump cutoff switch 25 is arranged on pump 22 and a spring-loaded check valve 26 is arranged on tube 21 below the pump 22. A pickup bale 27 is connected to the upper end of assembly 20 to aid in placing it Within and removing it from pile 14. Driving head 18 is provided with a cable port 30 containing a wire line pressure packing means 31 to seal off an electrical cable 32 as it passes from the exterior of driving head 18 to the interior thereof where it is connected to pump 22. Cable 32 connects to a power source at the surface for supplying power to operate pump 22. A water ll-up port 33 is also formed in driving head 18. The upper portion of driving head 18 forms an anvil for contact with the steam hammer.
Assembly 2t) is self standing during driving operations by means of the centralizers 21a. A plate 34 seals the anvil portion 18a of driving head 18 from the interior thereof.
In operation, referring particularly to FIGS. 1 and 3, the initial section of pile 14a is welded to the lower end of driving head 18 and section 14a is driven by means of hammer 13 downwardly to the hard, dense sand formation 15. When pile section 14a reaches refusal in sands 15, pile driving hammer 13 is removed from the pile and jet-line pump assembly 2()` is inserted in the top of pile section 14a and lowered into it by a line connected to bale 27. Cable 32 is connected to pump 22 prior to lowering the assembly in the pile. Water, illustrated as at 35, is supplied to the interior of piling 14a through the upper end thereof. The Water is supplied to pile 14a until its level is above the pump 22. The pump is then operated and water is pumped through tubular member 21 and out perforations 23 to wash assembly 20 through the soft sand and silt 16 to the hard-packed sand 15 below it. The assembly may be forced down by means not shown if the weight of the assembly and the washing action does not cause it to move down. While this operation is being performed, a new pile section 14b is welded to the lower end of driving head 18 and positioned above section 14a. Then the surface end of electrical lead 32 is disconnected from the source of power to which it is connected and the lead is run through section 14b and head 18, and through opening 30 where it is packed olf by packing means 31. Lead 32 is then reconnected to the power source on barge 10. This is done so that the pump may continue to run while the new pile section 14b is being welded in position to the top of pile section 14a. After the two sections have been welded together, steam hammer 13 is lowered onto the top of driving head 18. At this time the water level may be raised into section 14b, if desired, through fill-up line 33.
Driving with steam hammer 13 is then commenced with pump 22 in operation. Resistance to driving of the pile 14 is reduced by the jetting action of the water through jet-line pump assembly 20 which permits additional penetration of the pile. During driving operations, the water level in the pile is maintained above the level of pump 22 through iill-up hose 33.
It is possible to continue taking suction (taking into consideration the design of the pump) at the higher pressure maintained by the water within pile 14 during driv` ing and upstage this pressure for jetting. The assembly operates, then, as during welding, providing greater jet pressure than where hydrostatic pressure alone is used.
Also, it is possible to operate by hydrostatic pressure alone when the water pressure within the piling is suiciently great. The waterproof, pressure-activated switch 25 cuts out and turns pump 22 olf automatically without surface control. When the pressure drops sufficiently, switch 25 turns pump 22 on. When the pump is turned olf, fluid entry to tubular member 21 is through the spring-loaded check valve 26.
The technique of the present invention overcomes disadvantages in the use of hydrostatic pressure alon-e to jet water through perforations 23. Where hydrostatic pressure alone is used, jetting must be stopped during the periods when the lead pile sections and driving head are rewelded to the driven piling. At this time sand tends to plug the jet-line tube and to tighten about the piling which greatly increases driving resistance, barge time, and total costs. The Welding period may take from one and onehalf to two hours for each pile. The inverted submersible pump 22 maintains jet ow through perforations 23 throughout the welding period.
Additional sections of pile are added on and the process is continuously repeated to achieve the desired pile penetration.
Driving head 18 is removed when necessary by cutting7 off its connection to the last or new section of pile added l and welding the upper end of the next pile section added to the pile to the driving head.
Having fully described the nature, method, objects, and advantages of my invention, I claim:
1. A method for driving tubular pile sections into the ground in a substantially vertical direction in which a driving member adapted to be attached to a hammer is attachable to the upper end of each pile section to be driven comprising the steps of:
arranging in a longitudinally extending position in a previously driven pile section below the level of a column of water contained in said pile section a tubular means provided with perforations at its lower end and a pump at its upper end;
attaching a new pile Section to said driven pile section;
attaching said driving member to the top of said new pile section; and
then hammering said driving member and said attached pile sections into the ground While simultaneously operating said pump to pump water contained in said pile sections through said tubular means and out said perforations.
2. A method as recited in claim 1 in which new pile sections are added where necessary by disconnecting said driving member, attaching a new pile section to said drivin g member, and then attaching the new pile section to the driven pile section to which said driving member had been attached.
3. A method as recited in claim 2 in which said pump is operated to pump water through said tubular means While said pile sections are being attached to each other and while said driving member is being disconnected from and attached to pile sections.
4. A method as recited in claim 3 which includes the steps of adding water to said pile sections to raise the level of water above the level of said pump an amount suflicient for hydrostatic pressure to stop operation of said pump and open a valve in said tubular means to permit water to flow through said tubular means and jet through said perforations under hydrostatic pressure alone.
5. A method as recited in claim 1 in which said pile sections are driven into the ground underlying water in which a more dense formation material underlies a zone of less dense material including the steps of:
driving piling to refusal through said zone of less dense material prior to the step of positioning said tubular means in said pile section;
removing said driving member; and
then after positioning said tubular means in said pile section, operating said pump to circulate water through said tubular means and said perforations to wash said tubular means downwardly within said piling to the lower tip thereof through said less dense material.
6. A method as recited in claim 5 in which new pile sections are added where necessary by disconnecting said driving member, attaching a new pile section to said driving member, and then attaching the new pile section to the driven pile section to which said driving member had been attached.
7. A method as recited in claim 6 in which said pump is operated to pump water through said tubular means while said pile sections are `being attached to each other and while said driving member is being disconnected from and attached to pile sections.
8. A method as recited in claim 7 which includes the steps of adding water to said pile sections to raise the level of water above the level of said pump an amount suicient for hydrostatic pressure to stop operation of said pump and open a valve in said tubular means to permit water to ow through said tubular means and jet through said perforations under hydrostatic pressure alone.
References Cited by the Examiner UNITED STATES PATENTS 911,971 2/1909 Gilbreth 61-53.74 X 955,729 4/1910 Welsh 6l-53.74 X 3,215,201 ll/l965 Lacy et al. 175-67 X CHARLES E. OCONNELL, Primary Examiner.
JACOB SHAPIRO, Examiner.