Grouting Seal For Piling

Abstract

A seal for sealing the annular space between the outer surface of a pile and the inner surface of a hollow-member such as a marine platform leg or skirt guide through which the pile is driven, the seal comprising an elastomeric body normally lying against the inner surface of the hollow member and peripherally attached thereto, and a cable encompassing the body such that when the cable is drawn tightly around the body in a central zone between its ends, the body is cinched or drawn into tight engagement with the pile to seal the annulus between it and the hollow member, for instance, while grout is being poured into the annulus and setting.

Description

This invention relates to a seal for sealing the annulus between an outer hollow member and a pile driven therethrough, and more particularly relates to a grouting seal to support a column of grout in said annulus while the grout is setting, especially during the installation in situ of marine platforms of the type used by oil well drilling and producing companies.

The prior art teaches several seal structures of this general type, adapted for use especially where the seal closes the annulus between a skirt guide or platform leg and a pile driven therethrough. The assignee of the present disclosure is also the owner of Harris U.S. Pat. No. 3,468,132 entitled "Skirt-Guide Packer For Piling" and also the owner of a co-pending application in the name of Thaxton, Ser. No. 876,246, filed Nov. 13, 1969 and entitled "Annulus Seal and Pile Wiper" and now U.S. Pat. No. 3,570,259. Both of the above prior art disclosures relate to more expensive seals capable of supporting a very high column of grout and especially well adapted for use in deep water where the accomplishment of a seal is difficult, and where great strength is required to support a very high column of grout because of its weight.

The present invention is intended to provide a simpler and less expensive seal which is particularly useful under conditions of operation which are not especially difficult, meaning for use in relatively shallower water. It is important to keep down the cost of such a seal because of the fact that it can be used only once and is needed for only a relatively short period of time, namely until the grout is fully set.

It is a principal object of this invention to provide a simple and economical seal for use in fairly shallow water and where the weight of the grout to be supported is not very great, as compared with the pressures and weights encountered, for instance, in depths exceeding 400 or 500 feet where the column of grout may be 80 or 90 feet high.

It is another important object of this invention to provide a seal which in unset condition occupies only a small radial annulus so that it can be used between a pile and the hollow member through which it passes where the space therebetween is radially very limited, a typical narrow annulus being in the neighborhood of 1 inch on each side.

Another important object of this invention is to provide a seal which is inexpensive to manufacture. For example, the present seal can be economically manufactured by merely building up layers of rubber and perhaps reinforcing fabrics around a mandrel, and then curing the seal on the mandrel before removing it. This structure is much simpler to manufacture than an inflatable seal, or a seal having a skeleton of reinforcement wires.

It is another object of this invention to provide an annulus seal which contains reinforcement fabric located such that the portion of the structure which actually supports a column of grout is reinforced, whereas the remainder of the structure therebelow is not reinforced and is accordingly permitted a certain amount of stretch so as to make it possible to fixedly secure both the upper and the lower peripheral ends of the seal to the hollow member which carries it, the seal being sufficiently stretchable longitudinally so that it can be displaced inwardly to seal against the piling without requiring that the ends of the seal approach each other.

It is still another important object of the invention to provide a seal structure which is cinched in against the piling by an encircling portion of a cable which is also pulled through an opening in the wall of the hollow member which supports the seal, at least one end portion of the cable being carried to the surface or else taken to a hydraulic or pneumatic cylinder whereby the cable can be tensioned in order to cinch the seal against the piling.

It is another object of this invention to provide a stuffing box arrangement in the sidewall of the hollow member such that when the cable is passed through the stuffing box, water will be excluded from the annulus thereby. By this means, the seal is made to be cooperative with a frangible diaphragm which is usually carried in the lower end of the hollow member supporting the seal, whereby water is entirely excluded from the annulus between the pile and the hollow member until the pile is driven through the diaphragm. Just prior to driving the pile through the diaphragm, the seal may be tightened into contact with the piling to prevent a rush of silt and foreign matter entrained in the water into the annulus when the diaphragm is broken by the pile being passed through it.

Still a further object of the invention is to provide a cable anchoring and lead-out opening structure such that the cable is always provided with a smooth bend when it is being cinched about the seal, thereby avoiding damage to the cable as well as avoiding the requirement of excessive effort to draw the seal tightly against the piling.

Still another object of the invention is to provide an annular groove about the central zone of the elastomeric body to contain and guide the cable thereabout so that when the cable is slack in the groove the body can lie flat against the inner surface of the hollow member which supports it, and so that when the cable is pulled tight, it will be guided and maintained in the central zone of the elastomeric body, thereby avoiding the possibility that the cable might tend to droop and not provide a truly circumferential sealing path disposed in a plane lying substantially normal to the axis both of the piling and of the hollow member containing the seal.

Other objects and advantages of the invention will become apparent during the following discussion of the drawings, wherein:

FIG. 1 is a cross-section view taken through a hollow member such as a platform leg or a skirt guide which has been enclosed at its bottom by a diaphragm to exclude the entry of water, and which supports a seal according to the present invention in its interior;

FIG. 2 is a cross-section view through a hollow member as shown in FIG. 1 but showing a pile driven through the hollow member and the diaphragm and having the seal cinched tightly against it;

FIG. 3 is a section view taken through a hollow member and showing the arrangement of the cable therewithin, with the seal removed for the sake of clarity;

FIG. 4 is a section view similar to FIG. 3 but showing a pile and a seal located within the hollow member with the cable cinched in theretoward;

FIG. 5 is an enlarged sectional view through a portion of a seal carried by the inner surface of the hollow member; and

FIG. 6 is an enlarged sectional view of the seal cinched tightly against the piling and supporting a column of grout thereabove, the seal shown in FIG. 6 being somewhat modified to include reinforcing fabric therewithin.

Referring now to FIGS. 1 and 2, these figures show a hollow member 10 such as a platform leg or a skirt guide having a ring 11 welded onto its lower end and mating with another ring 12 bolted onto the ring 11 and supporting a diaphragm D. This structure is old and well known in the prior art, for instance, in Patent 3,468,132. The hollow member 10, as shown in FIG. 2, has a pile driven through it and rupturing the diaphragm D, the pile being driven into the bottom of the ocean floor in a manner well known per se in the prior art. The hollow member 10 has a tapered guide ring 13 welded to it to guide the pile member 15 as it is lowered through the seal so as to prevent the pile from striking the seal and perhaps damaging it. The inside diameter of the ring 13 is smaller than the outer diameter of the pile 15 so that grout can pass downwardly into contact with the elastomeric seal which is about to be described.

The seal 20 can best be seen in FIGS. 5 and 6. FIG. 5 shows the seal in relaxed condition and comprising an elastomeric body having a bead at each peripheral end, such as the bead 21 and the bead 22 which are preferably reinforced by cord or cable in a suitable manner. At least the upper one of these beads is clamped tightly to the inner surface of the hollow member 10 by suitable rings 17 and 18 which are preferably welded to the wall of the hollow member 10. The seal body 20 may comprise a straight cylindrical sleeve, but in the preferred embodiments as shown in FIGS. 5 and 6 the body includes a groove 23 located between the ends 21 and 22 of the body for the purpose hereinafter stated. Opposite the groove 23 is an enlarged sealing pad 24 which can be of any suitable shape, for instance, a truncated pyramid shape which can then distort somewhat as shown in FIG. 6 when the seal is cinched tightly against the pile 15.

The cinching of the seal pad 24 against the pile 15 is accomplished in the present embodiment by a steel cable 30 having a loop portion which surrounds the seal, and in the case of the seal shown in FIGS. 5 and 6 this cable occupies the groove 23. FIG. 3 shows that one end 31 of the cable 30 passes through a diagonally drilled hole in the hollow member 10 and is anchored therein, for instance, by providing an enlargement on the end of the cable which cannot be withdrawn through the hole. This hole should also be sealed to prevent liquid from entering therethrough. The free end portion of the cable 30 passes through another hole which is positioned through the wall of the hollow member 10 at such a point that the cable goes about one and one-third of the way around the seal before leaving the hollow member through the opening in its side, this opening being labelled 14, and being disposed diagonally, so that the cable is not bent severely as it leaves the hollow member 10. The hole 14 communicates with a tube 19 which is welded to the side of the hollow member 10 and bends upwardly so that the cable can be pulled tight from above, preferably from a position on the platform which is being installed. The free end of the cable 32 comes out of the pipe 19 and passes through a stuffing box 34 so as to exclude water from entering into the space between the outer periphery of the seal 20 and the inner surface of the hollow member 10. A guard member 35 is welded to the side of the hollow member 10 in order to protect the tube 19 from possible mechanical damage and crushing.

As mentioned above, the free end of the cable 32 can either be taken all the way up to the surface where it can be manipulated manually or by mechanical leverage, or alternatively it can be taken to some power device such as an hydraulic or pneumatic cylinder (not shown) which can be used to pull the cable 30 with sufficient force to cinch the seal 20 tightly against the pile 15 to prevent the passage of fluids either upwardly or downwardly through the annulus. The annulus which is of concern in the present disclosure is labelled A in FIG. 6, and in the final step in which the seal participates the annulus above the approximate center of the seal is filled with grout G, which extends upwardly between the pile 15 and the hollow member 10 in a manner well known per se.

FIG. 6 shows a modification of the seal 20 to the extent that reinforcing fabric 28 has been introduced to extend from the upper bead 27 where it is anchored to a point somewhat below the cable groove 23, this point being labelled 29 in FIG. 6. The fabric, therefore, makes the upper portion of the seal above the cable groove 23 substantially inextensible so that it has the strength to support a high column of grout G, but in view of the fact that the fabric 28 ends at a point 29, which is in the vicinity of the cinched central zone of the seal, the lower portion of the seal remains axially stretchable so that the lower portion of the seal can give as the cable cinches the seal inwardly and compresses its pad 24 against the piling 15. For this reason, both of the peripheral ends of the seal can be fixed in the axial direction by the rings 17 and 18 without preventing the seal from being cinched inwardly by the cable 30.

The present invention is not to be limited to the exact forms shown in the drawings for obviously changes may be made therein within the scope of the following claims.

Claims

I claim:

1. A seal for sealing the annulus between the inner surface of a hollow member and the outer surface of a pile passing substantially coaxially therethrough in spaced relationship, comprising:

a. an annular body of elastomeric material having an outer surface sized normally to lie against the inner surface of said hollow member in said annulus;

b. said annular body having upper and lower peripheral ends spaced apart axially of the hollow member by a distance which is great as compared with the spacing between the inner surface of the hollow member and the outer surface of the pile, and the central portion of the body having an annular groove in its outer surface spaced from said upper and lower ends and said central portion of the body being thickened so that it extends partway across said spacing from the body's outer surface to form an annular sealing pad disposed opposite said groove and extending from the inner surface of the body toward the pile;

c. means for securing the upper end of the body to the inner surface of said hollow member;

d. cable means having an annularly disposed portion between the inner surface of the hollow member and the elastomeric body and surrounding the latter within said annular groove; and

e. means for tensioning the annular portion of the cable means to draw it tightly around the elastomeric body and seal the latter against the outer surface of the pile.

2. In a seal as set forth in claim 1, said cable means having one end anchored to the hollow member at a location between the ends of the elastomeric body and having said annular portion extending more than all the way around the body; the hollow member having an opening therethrough located between the ends of the elastomeric body; and the cable means having a second portion extending outside the member and comprising said means for tensioning the annular portion when said second portion is tensioned outwardly of said hollow member.

3. In a seal as set forth in claim 2, cable guiding means communicating with said opening in the hollow member and leading the second portion of the cable means therethrough; and stuffing box means in said guiding means and sealing said opening.

4. In a seal as set forth in claim 1, said sealing pad being disposed integrally around the inner surface of said body and being of truncated triangular cross-section.

5. In a seal as set forth in claim 1, means for securing the peripheral lower end of the body to the inner surface of said hollow member.

6. In a seal as set forth in claim 5, said elastomeric body having upper and lower bead portions around its peripheral ends captivated in said securing means, and said body having reinforcing fabric means embedded therein and anchored in said upper bead portion and extending downwardly and terminating beyond the annular portion of said cable means and above the lower peripheral end of the body.

7. In a seal as set forth in claim 5, said elastomeric body having reinforcing fabric means embedded therein and anchored in said upper peripheral end and extending downwardly between said groove and said pad and terminating above said lower peripheral end.