Construction and use of subsea bore holes
First Claim
1. A method of constructing a subsea bore hole about 10 to 50 meters in diameter provided with a stable wall comprising the steps of:
- (a) placing a self-supporting caisson structure at a chosen location at sea, said caisson structure having an internal space from which external water may be excluded;
(b) drilling a plurality of bore holes around the circumference of a ring of large diameter through said internal space of said caisson;
(c) supplying a selected material to said ring bore holes which is capable of interacting with the material surrounding said ring bore holes to locally stabilize surrounding geologic formations; and
(d) forming a central shaft within said ring;
wherein said ring bore holes and locally stabilized geologic formations form a stable wall of large diameter for said central shaft.
1 Assignment
0 Petitions
Accused Products
Abstract
It is proposed to construct a large diameter subsea bore hole (e.g. about 10 to 50 meters in diameter) provided with a stable wall by a method which comprises drilling a number of bore holes around the circumference of a ring of large diameter, supplying to the ring bore holes material to locally stabilize the surrounding geologic formations, and forming a central bore hole, or shaft, within the perimeter of the ring by drilling and reaming or by excavation. The ring bore holes and locally stabilized geologic formations form a stable wall of large diameter for the central bore hole shaft. It is contemplated that a large diameter subsea bore hole of the type described above could be used for the safe emplacement and disposal beneath the seabed of a large waste job object such as the shielded reactor core of a decommissioned nuclear submarine, or of other waste objects containing radioactive material.
17 Citations
10 Claims
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1. A method of constructing a subsea bore hole about 10 to 50 meters in diameter provided with a stable wall comprising the steps of:
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(a) placing a self-supporting caisson structure at a chosen location at sea, said caisson structure having an internal space from which external water may be excluded; (b) drilling a plurality of bore holes around the circumference of a ring of large diameter through said internal space of said caisson; (c) supplying a selected material to said ring bore holes which is capable of interacting with the material surrounding said ring bore holes to locally stabilize surrounding geologic formations; and (d) forming a central shaft within said ring; wherein said ring bore holes and locally stabilized geologic formations form a stable wall of large diameter for said central shaft. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of constructing a large-diameter subsea bore hole provided with a stable wall comprising the steps of:
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(a) loading an outer structural caisson and an inner freeze-wall caisson onto a barge and transporting said caissons to a preselected offshore site; (b) lifting said outer caisson off said barge by a floating crane vessel; (c) lowering said outer caisson and installing said outer caisson on a seabed at said offshore site; (d) stabbing and driving outer piles using followers and an above-water hammer; (e) lifting said inner freeze-wall caisson off said barge with said crane and installing said freeze-wall caisson within said outer caisson on said seabed site; (f) stabbing and driving inner pin piles and installing both said caissons by grouting said outer and inner piles; (g) constructing freeze walls for carrying freeze lines by drilling a ring of bore holes within an annular space within said inner caisson; (h) freezing said caisson freeze wall and a subsoil formation underneath said site by pumping chilled brine through said freeze lines; (i) loading a deck module and a mining headgear module onto said barge and transporting them to said site; (j) installing said deck module on said outer caisson and supporting said deck module by upwardly extended piles; (k) installing said mining headgear module; (l) installing a span bridge with a jack-up rig to allow servicing of mining operations; and (m) excavating a large-diameter central shaft to a desired depth and concrete-casing said shaft as it is being constructed.
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8. A method of disposal of large, highly radioactive waste objects comprising the steps of:
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(a) loading an outer structural caisson and an inner freeze-wall caisson onto a barge and transporting said caissons to a preselected offshore site; (b) lifting said outer caisson off said barge by a floating crane vessel; (c) lowering said outer caisson and installing said outer caisson on a seabed at said offshore site; (d) stabbing and driving outer piles using followers and an above-water hammer; (e) lifting said inner freeze-wall caisson off said barge with said crane and installing said freeze-wall caisson within said outer caisson on said seabed site; (f) stabbing and driving inner pin piles and installing both said caissons by grouting said outer and inner piles; (g) constructing freeze walls for carrying freeze lines by drilling a ring of bore holes within an annular space within said inner caisson; (h) freezing said caisson freeze wall and a subsoil formation underneath said site by pumping chilled brine through said freeze lines; (i) loading a deck module and a mining headgear module onto said barge and transporting them to said site; (j) installing said deck module on said outer caisson and supporting said deck module by upwardly extended piles; (k) installing said mining headgear module; (l) installing a span bridge with a jack-up rig to allow servicing of mining operations; (m) excavating a large-diameter central shaft to a desired depth and concrete-casing said shaft as it is being constructed; (n) removing said deck and mining modules after said excavating is completed; (o) placing at least one said waste object at a bottom of said central shaft; and (p) back-filling said central shaft. - View Dependent Claims (9, 10)
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Specification