An underwater gravity anchor relay type lowering method and lowering system
By gradually de-releasing the gravity anchors with multiple wire ropes in multiple temporary working areas, the problem of limited depth of de-releasing the gravity anchors underwater is solved, and rapid and convenient construction in deep water environments is achieved, and construction costs are reduced.
Patent Information
- Application Number
- CN202310596504.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-05-22
- Publication Date
- 2025-07-25
- Estimated Expiration
- 2043-05-22
AI Technical Summary
In the prior art, the lowering depth of the underwater gravity anchor is limited by the floating lifting height, which leads to the inability to uninstall the wire rope when the water depth is greater than the floating lifting height, which limits the selection of anchor positions and the selection of floating lifting models, and increases construction costs.
The method of connecting multiple wire ropes is adopted to use multiple temporary working areas with different water depths, and the gravity anchor is gradually lowered to the seabed surface through a floating crane, and the length of the wire rope is gradually increased until the water depth in the target area is greater than the height of the floating crane.
When the water depth in the target working area is greater than the floating lifting height, the gravity anchor is quickly and conveniently completed, solving the problem of the inability to remove the wire rope, simplifying the construction plan, and reducing costs.
Smart Images
Figure CN116395081B_ABST
Abstract
Description
Technical Field
[0001] This specification relates to the technical field of bridge construction, and particularly to a method and system for lowering an underwater gravity anchor by relay force. Background Art
[0002] With the progress of technology, cross-sea bridges in the world have developed rapidly, with an increasing number and the depth of the crossed sea areas constantly breaking through. As the main component for positioning and mooring marine construction vessels and various facilities, the underwater gravity anchor is mainly fixed to the seabed by its own weight, can withstand vertical and horizontal loads, has the characteristics of high bearing capacity, good stability, no need for maintenance and reliable construction. Especially in the construction environment of deep-water bare rock, it provides a limited underwater mooring system for construction vessels, self-floating facilities, etc. The underwater gravity anchor that can be lowered to an ideal position with a relatively large depth is increasingly being applied to cross-sea bridge construction.
[0003] However, in the prior art, restricted by the floating crane, the depth to which the underwater gravity anchor can be lowered is less than the lifting height of the floating crane. When the water depth is greater than the lifting height of the floating crane, the wire rope will penetrate into the water surface and cannot be released, or the position where the gravity anchor is cast is changed to avoid the deep-water area. No matter which method is adopted, it will seriously restrict the selection of the proposed anchoring position during the construction of the gravity anchor or the selection of the floating crane model, bring many adverse factors to the preparation of the construction plan, limit the process selection, and increase the construction cost. Summary of the Invention
[0004] In view of the deficiencies of the prior art, an object of this specification is to provide a method and system for lowering an underwater gravity anchor by relay force, which can solve the problem that during the lowering process of the underwater gravity anchor, due to the water depth being greater than the lifting height of the floating crane, the wire rope penetrates into the water surface and cannot be released.
[0005] To achieve the above object, an embodiment of this specification provides a method for lowering an underwater gravity anchor by relay force, including the following steps:
[0006] Step S10: Drive the barge loaded with the gravity anchor to the first temporary working area for temporary anchoring and fixing;
[0007] Step S20: Drive the floating crane to the side of the barge for temporary anchoring and fixing;
[0008] Step S30: Use the floating crane to lower the gravity anchor to the seabed surface; wherein, one end of the first wire rope is suspended on the hook of the floating crane, the other end of the first wire rope is fixedly connected to the gravity anchor, and the length of the first wire rope is less than the maximum lifting height of the floating crane; the water depth of the first temporary working area is less than the length of the first wire rope;
[0009] Step S40: Connect the (i + 1)-th steel wire rope above the i-th steel wire rope; where the initial value of i is 1; one end of the (i + 1)-th steel wire rope is fixedly connected to the top end of the i-th steel wire rope, and the other end is fixedly connected to the hook; the length of the (i + 1)-th steel wire rope is less than the maximum lifting height of the floating crane.
[0010] Step S50: Lift the hook to disengage the gravity anchor from the seabed surface.
[0011] Step S60: Determine whether the total length of all the steel wire ropes is greater than the water depth of the target working area.
[0012] If so, drive the floating crane carrying the gravity anchor to the target working area to lower the gravity anchor.
[0013] If not, drive the floating crane carrying the gravity anchor to the (i + 1)-th temporary working area and lower the gravity anchor to the seabed surface; let i = j + 1, and repeat the above Step S40, Step S50, and Step S60, where j is the number of times Step S60 is performed; the water depth of the (i + 1)-th temporary working area is less than the total length of all the steel wire ropes and greater than the water depth of the i-th temporary working area.
[0014] As a preferred implementation, before Step S30, use the floating crane suspended with the first steel wire rope to lift the gravity anchor on the barge. After the gravity anchor is separated from the barge, drive the barge away from the first temporary working area.
[0015] As a preferred implementation, after the step of lowering the gravity anchor to the seabed surface, the hook of the floating crane is above the sea level.
[0016] The embodiments of this specification provide an underwater gravity anchor relay lowering system for implementing the underwater gravity anchor relay lowering method described in any of the above embodiments. The underwater gravity anchor relay lowering system includes a gravity anchor, a barge, a floating crane, multiple steel wire ropes, and multiple temporary working areas; the gravity anchor is placed on the barge, and the floating crane can lift and lower the gravity anchor to the seabed surface of different temporary working areas through the steel wire ropes.
[0017] As a preferred implementation, the top surface of the gravity anchor is provided with multiple anchor throwing and orientation adjusting mooring points, a buoy anchor seat, and multiple lifting anchor seats; the anchor throwing and orientation adjusting mooring points are used to adjust the attitude of the gravity anchor during the lowering process, and the anchor throwing and orientation adjusting mooring points are located outside the lifting anchor seats; the buoy anchor seat is used to connect the buoy, and the buoy anchor seat is located between two of the anchor throwing and orientation adjusting mooring points; the lifting anchor seats are used to connect with the steel wire ropes.
[0018] As a preferred embodiment, the gravity anchor is provided with an exhaust hole extending in the vertical direction and penetrating the gravity anchor; one end of the bottom surface of the gravity anchor has a tooth block formed by welding steel plates; a slope is provided between the top surface of the gravity anchor and the tooth block, and a cable anchor seat is provided on the slope for providing positioning and anchoring force for the construction ship after connecting the cable.
[0019] As a preferred embodiment, the floating crane is provided with a lifting device, a hook is fixed at the end of the lifting device, and the hook includes a double hook in an inverted T shape.
[0020] As a preferred embodiment, the hook includes a main hook and a sub-hook, and the main hook of the floating crane lifts the gravity anchor through the steel wire rope.
[0021] As a preferred embodiment, the steel wire rope is a spiral steel wire bundle formed by twisting steel wires according to a predetermined rule, and the length of each steel wire rope is less than the maximum lifting height of the floating crane.
[0022] As a preferred embodiment, the water depth of the temporary working area is equal to the sea level elevation minus the seabed elevation; the water depths of multiple temporary working areas increase in sequence; the multiple temporary working areas are sorted in ascending order of water depth, and the water depth of the nth temporary working area is greater than (n - 1) times the maximum lifting height of the floating crane and less than n times the maximum lifting height of the floating crane; where n is an integer greater than 0.
[0023] Beneficial effects:
[0024] The underwater gravity anchor relay type lowering method provided by this embodiment utilizes multiple temporary working areas with different water depths and adopts the method of connecting multiple steel wire ropes multiple times. In the case of using seabed surfaces at different depths as operation platforms, it solves the problem that during the lowering process of the underwater gravity anchor, due to the water depth being greater than the lifting height of the floating crane, the steel wire rope sinks into the water surface and cannot be released. When the water depth of the target working area is greater than the lifting height of the floating crane, it can quickly and conveniently realize the lowering of the gravity anchor.
[0025] Referring to the following description and drawings, specific embodiments of the present invention are disclosed in detail, indicating the ways in which the principles of the present invention can be adopted. It should be understood that the embodiments of the present invention are not limited in scope thereby.
[0026] Features described and / or illustrated for one embodiment can be used in the same or similar way in one or more other embodiments, combined with features in other embodiments, or replace features in other embodiments.
[0027] It should be emphasized that the term "comprising / including", as used herein, refers to the presence of features, whole units, steps or components, but does not exclude the presence or addition of one or more other features, whole units, steps or components. Description of the Drawings
[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.
[0029] Figure 1 It is a flowchart of the steps of an underwater gravity anchor relay type lowering method provided in this embodiment;
[0030] Figure 2 It is a schematic top view structure of a gravity anchor provided in this embodiment;
[0031] Figure 3 It is a schematic front view structure of a gravity anchor provided in this embodiment;
[0032] Figure 4 It is Figure 1 A schematic structural diagram after the floating crane lifts the gravity anchor after step S20 and before step S30 in
[0033] Figure 5 It is Figure 1 A schematic structural diagram after step S30 in
[0034] Figure 6 It is Figure 1 A schematic structural diagram after step S40 in
[0035] Figure 7 It is Figure 1 A schematic structural diagram after step S50 in
[0036] Figure 8 It is Figure 1 A schematic structural diagram after it is judged to be yes after step S50 in , and the floating crane carrying the gravity anchor travels to the target working area for lowering the gravity anchor.
[0037] Description of the Reference Numerals:
[0038] 1. Gravity anchor; 11. Anchor throwing and alignment mooring point; 12. Buoy anchor seat; 13. Lifting anchor seat; 14. Exhaust hole; 15. Mooring rope anchor seat; 16. Tooth block;
[0039] 2. Barge;
[0040] 3. Floating crane; 31. Lifting device; 32. Hook
[0041] 41. First wire rope; 42. Second wire rope
[0042] 51. Water depth of the first temporary working area; 52. Water depth of the target working area
[0043] 6. Sea level; 7. Seabed surface Detailed implementation manner
[0044] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.
[0045] It should be noted that when an element is referred to as being "disposed on" another element, it can be directly on the other element or there can also be another intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be another intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for the purpose of illustration and do not represent the only implementation.
[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific implementation manners and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.
[0047] Please refer to Figure 1 、 Figures 4 to 8 . The embodiment of the present application provides an underwater gravity anchor relay type lowering method, including the following steps:
[0048] Step S10: Drive the barge 2 loaded with the gravity anchor 1 to the first temporary working area for temporary anchoring and fixing.
[0049] Step S20: Drive the floating crane 3 to the side of the barge 2 for temporary anchoring and fixing.
[0050] Among them, the order of step S10 and step S20 can be interchanged, that is, the floating crane 3 can be first driven to the vicinity of the first temporary working area for temporary anchoring and fixing, and then the barge 2 loaded with the gravity anchor 1 can be driven to the first temporary working area beside the floating crane 3 for temporary anchoring and fixing. Or, step S10 and step S20 can be carried out simultaneously, and the floating crane 3 and the barge 2 loaded with the gravity anchor 1 are simultaneously driven to the first temporary working area and its side for temporary anchoring and fixing, so as to speed up the construction progress and save construction time.
[0051] In this embodiment, before step S30, the floating crane 3 hanging the first wire rope 41 is used to lift the gravity anchor 1 on the barge 2, so that the gravity anchor 1 is separated from the barge 2, as Figure 4 shown. After the gravity anchor 1 is separated from the barge 2, the barge 2 is driven away from the first temporary working area.
[0052] Step S30: Use the floating crane 3 to lower the gravity anchor 1 to the seabed surface 7, as Figure 5 shown.
[0053] Among them, one end of the first wire rope 41 is hung on the hook 32 of the floating crane 3, and the other end of the first wire rope 41 is fixedly connected to the gravity anchor 1. The length of the first wire rope 41 is less than the maximum lifting height of the floating crane 3. The water depth 51 of the first temporary working area is less than the length of the first wire rope 41.
[0054] The seabed surface 7 is the seabed foundation bed, and in this embodiment, it is all bare rock. Of course, this lowering method can also be applied to the foundation bed with a covering layer.
[0055] Step S40: Connect the (i + 1)-th wire rope above the i-th wire rope, as Figure 6 shown.
[0056] Among them, the initial value of i is 1. One end of the (i + 1)-th wire rope is fixedly connected to the top end of the i-th wire rope, and the other end is fixedly connected to the hook 32. The length of the (i + 1)-th wire rope is less than the maximum lifting height of the floating crane 3.
[0057] Step S50: Lift the hook 32 to separate the gravity anchor 1 from the seabed surface 7, which is convenient for subsequent movement of the gravity anchor 1, as Figure 7 shown.
[0058] Step S60: Determine whether the total length of all wire ropes is greater than the water depth 52 of the target working area.
[0059] If so, drive the floating crane 3 carrying the gravity anchor 1 to the target working area to lower the gravity anchor 1 and complete the construction, as Figure 8 shown.
[0060] If not, move the floating crane 3 carrying the gravity anchor 1 to the (i + 1)-th temporary working area, and lower the gravity anchor 1 to the seabed surface 7; set i = j + 1, and repeat the above steps S40, S50, and S60, where j is the number of times step S60 is performed.
[0061] Among them, the water depth of the (i + 1)-th temporary working area is less than the total length of all steel wire ropes and greater than the water depth of the i-th temporary working area.
[0062] As Figure 8 shown, if the total length of the first steel wire rope 41 and the second steel wire rope 42 is greater than the water depth 52 of the target working area, move the floating crane 3 carrying the gravity anchor 1 to the target working area to lower the gravity anchor 1, and complete the construction.
[0063] In other possible embodiments, the total length of the first steel wire rope 41 and the second steel wire rope 42 is not greater than the water depth 52 of the target working area. Therefore, move the floating crane 3 to the second temporary working area and lower the gravity anchor 1 to the seabed surface 7. Set i = j + 1 = 1 + 1 = 2, and repeat the above steps S40, S50, and S60, that is, connect the third steel wire rope above the second steel wire rope 42; lift the hook 32 to disengage the gravity anchor 1 from the seabed surface 7; determine whether the total length of the three steel wire ropes is greater than the water depth 52 of the target working area. If so, move the floating crane 3 carrying the gravity anchor 1 to the target working area to lower the gravity anchor 1; if not, move the floating crane 3 carrying the gravity anchor 1 to the third temporary working area and lower the gravity anchor 1 to the seabed surface 7, set i = j + 1 = 2 + 1 = 3, and repeat the above steps S40, S50, and S60.
[0064] The underwater gravity anchor relay lowering method provided by this embodiment uses multiple temporary working areas with different water depths, and adopts the method of connecting multiple steel wire ropes multiple times. In the case of using seabed surfaces 7 at different depths as working platforms, it solves the problem that during the lowering process of the underwater gravity anchor 1, due to the water depth being greater than the lifting height of the floating crane 3, the steel wire rope cannot be released after entering the water surface. When the water depth 52 of the target working area is greater than the lifting height of the floating crane 3, the gravity anchor 1 can be quickly and conveniently lowered.
[0065] In this embodiment, after the step of lowering the gravity anchor 1 to the seabed surface 7 (that is, the situation where the judgment in steps S30 and S50 is no), the hook 32 of the floating crane 3 is above the sea level 6, which is convenient for subsequent extension of the steel wire rope. The sea level 6 is the sea water level, and by default, the high tide sea level 6 under the relatively unfavorable working conditions is used.
[0066] Based on the same inventive concept, an underwater gravity anchor relay type lowering system is further provided in an embodiment of the present invention, as described in the following embodiments. It should be noted that the lowering system of this embodiment can execute the steps in the above-mentioned underwater gravity anchor relay type lowering method. For a detailed description of related content, please refer to the above-mentioned lowering method section, and details will not be repeated here.
[0067] In this embodiment, the implementation manner of the lowering system corresponds to the implementation manner of the lowering method. It can solve the technical problems solved by the implementation manner of the lowering method and correspondingly achieve the technical effects of the implementation manner of the lowering method. Specifically, details of this application will not be elaborated here.
[0068] In this embodiment, the underwater gravity anchor relay type lowering system includes a gravity anchor 1, a barge 2, a floating crane 3, multiple steel wires, and multiple temporary working areas. The gravity anchor 1 is placed on the barge 2, and the floating crane 3 can lift the gravity anchor 1 through the steel wire and lower it to the seabed surface 7 of different temporary working areas. The composition of this underwater gravity anchor relay type lowering system is simple. When the water depth 52 of the target working area is greater than the lifting height of the floating crane 3, the gravity anchor 1 can be quickly and conveniently lowered.
[0069] As Figure 2 and Figure 3 shown, the top surface of the gravity anchor 1 is provided with multiple anchor throwing and orientation adjusting mooring points 11, a buoy anchor seat 12, and multiple lifting anchor seats 13. The anchor throwing and orientation adjusting mooring points 11 are used to adjust the attitude of the gravity anchor 1 during the lowering process. The anchor throwing and orientation adjusting mooring points 11 are located outside the lifting anchor seats 13. The buoy anchor seat 12 is used to connect the buoy. The buoy anchor seat 12 is located between two of the anchor throwing and orientation adjusting mooring points 11. The lifting anchor seats 13 are used to connect with the steel wire.
[0070] Specifically, the gravity anchor 1 is provided with an exhaust hole 14 extending in the vertical direction and penetrating the gravity anchor 1. The exhaust hole 14 is preferably located at the center of the gravity anchor 1, which can reduce the adsorption of the gravity anchor 1 by silt after landing. One end of the bottom surface of the gravity anchor 1 has a tooth block 16 made of welded steel plates. There is an inclined surface between the top surface of the gravity anchor 1 and the tooth block 16, and a mooring rope anchor seat 15 is provided on the inclined surface, which is used to provide positioning and anchoring force for the construction ship after connecting the mooring rope. This gravity anchor 1 can be used as a positioning device for the offshore construction ship and provide anchoring force for the positioning system of the construction ship.
[0071] As Figure 4As shown, the floating crane 3 is a crane ship, which is provided with a lifting device 31 for lifting various lifted objects in offshore construction operations. A hook 32 is fixed to the end of the lifting device 31, and the hook 32 includes a double hook in an inverted T shape. The hook 32 may include a main hook and a sub-hook, and the main hook of the floating crane 3 lifts the gravity anchor 1 through the steel wire rope.
[0072] The barge 2 provided in this embodiment can be an engineering ship that can carry goods and travel on the sea, and has the characteristics of shallow draft, large cargo capacity, and large cargo area.
[0073] Specifically, the steel wire rope can be a spiral steel wire bundle formed by twisting steel wires with mechanical properties and geometric dimensions meeting the requirements according to a predetermined rule, and is used to lift the gravity anchor 1. The length of each steel wire rope is less than the maximum lifting height of the floating crane 3.
[0074] In this embodiment, the water depth of the temporary working area is equal to the elevation of sea level 6 minus the elevation of the seabed 7. The water depths of multiple temporary working areas increase in sequence. Sorting multiple temporary working areas from shallowest to deepest water depth, the water depth of the nth temporary working area is greater than (n - 1) times the maximum lifting height of the floating crane 3 and less than n times the maximum lifting height of the floating crane 3. Wherein, n is an integer greater than 0, and can be, for example, 1, 2, 3, …….
[0075] It should be noted that in the description of this specification, terms such as "first", "second", etc. are only used for descriptive purposes and to distinguish similar objects, and there is no sequence between them, nor can they be understood as indicating or implying relative importance. In addition, in the description of this specification, unless otherwise stated, the meaning of "multiple" is two or more.
[0076] Any numerical value cited in this article includes all values from the lower limit value to the upper limit value increasing in increments of one unit, and there is an interval of at least two units between any lower value and any higher value. For example, if it is stated that the value of the quantity of a component or a process variable (such as temperature, pressure, time, etc.) is from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, then the purpose is to illustrate that values such as 15 to 85, 22 to 68, 43 to 51, 30 to 32, etc. are also explicitly listed in this specification. For values less than 1, a unit is appropriately considered to be 0.0001, 0.001, 0.01, 0.1. These are merely examples of what is intended to be clearly expressed, and it can be considered that all possible combinations of the numerical values listed between the lowest value and the highest value are clearly set forth in this specification in a similar manner.
[0077] Unless otherwise indicated, all ranges include the endpoints and all numbers between the endpoints. The term "about" or "approximate" used in connection with a range is inclusive of the endpoints of the range. Thus, "about 20 to 30" is intended to cover "about 20 to about 30", including at least the specified endpoints.
[0078] All articles and references disclosed, including patent applications and publications, are incorporated herein by reference for various purposes. The term "consisting essentially of" in describing a combination shall include the identified elements, ingredients, components or steps as well as other elements, ingredients, components or steps that do not materially affect the basic novel characteristics of the combination. The use of the terms "comprising" or "including" to describe the combinations of elements, ingredients, components or steps herein also contemplates embodiments consisting essentially of these elements, ingredients, components or steps. By using the term "may" herein, it is intended that any of the attributes described as "may" include be optional.
[0079] A plurality of elements, ingredients, components or steps can be provided by a single integrated element, ingredient, component or step. Alternatively, a single integrated element, ingredient, component or step may be separated into discrete plural elements, ingredients, components or steps. The disclosure of the articles "a" or "an" used to describe an element, ingredient, component or step is not intended to exclude other elements, ingredients, components or steps.
[0080] It should be understood that the above description is for purposes of illustration and not limitation. Many embodiments and many applications other than the examples provided will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of the present teachings should not be determined with reference to the above description, but should be determined with reference to the appended claims and the full scope of equivalents to which those claims are entitled. For the sake of completeness, all articles and references, including patent applications and published disclosures, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein from the foregoing claims is not intended to forego that subject matter, nor should the inventor be regarded as having not considered that subject matter to be part of the disclosed inventive subject matter.
Claims
1. An underwater gravity anchor relay type lowering method, characterized in that, It includes the following steps: Step S10: Drive the barge loaded with the gravity anchor to the first temporary working area for temporary anchoring and fixing; Step S20: Drive the floating crane to the side of the barge for temporary anchoring and fixing; Step S30: Use the floating crane to lower the gravity anchor to the seabed surface; wherein, one end of the first steel wire rope is suspended on the hook of the floating crane, the other end of the first steel wire rope is fixedly connected to the gravity anchor, and the length of the first steel wire rope is less than the maximum lifting height of the floating crane; the water depth of the first temporary working area is less than the length of the first steel wire rope; Step S40: Connect the (i + 1)th steel wire rope above the ith steel wire rope; wherein, the initial value of i is 1; one end of the (i + 1)th steel wire rope is fixedly connected to the top end of the ith steel wire rope, and the other end is fixedly connected to the hook; the length of the (i + 1)th steel wire rope is less than the maximum lifting height of the floating crane; Step S50: Lift the hook to disengage the gravity anchor from the seabed surface; Step S60: Determine whether the total length of all steel wire ropes is greater than the water depth of the target working area; If so, drive the floating crane carrying the gravity anchor to the target working area to lower the gravity anchor; If not, drive the floating crane carrying the gravity anchor to the (i + 1)th temporary working area and lower the gravity anchor to the seabed surface; make i = j + 1, and repeat the above steps S40, S50 and S60, where j is the number of times of performing step S60; the water depth of the (i + 1)th temporary working area is less than the total length of all steel wire ropes and greater than the water depth of the ith temporary working area.
2. The underwater gravity anchor relay type lowering method according to claim 1, wherein Before step S30, use the floating crane suspended with the first steel wire rope to lift the gravity anchor on the barge. After the gravity anchor is separated from the barge, drive the barge away from the first temporary working area.
3. The underwater gravity anchor relay type lowering method according to claim 1, wherein, After the step of lowering the gravity anchor to the seabed surface, the hook of the floating crane is above the sea level.
4. An underwater gravity anchor relay type lowering system, characterized in that, The underwater gravity anchor relay lowering system is used to implement the underwater gravity anchor relay lowering method according to any one of claims 1 - 3. The underwater gravity anchor relay lowering system includes a gravity anchor, a barge, a floating crane, multiple steel wire ropes and multiple temporary working areas; the gravity anchor is placed on the barge, and the floating crane can lift the gravity anchor through the steel wire ropes and lower it to the seabed surfaces of different temporary working areas.
5. The underwater gravity anchor relay type lowering system according to claim 4, wherein The top surface of the gravity anchor is provided with multiple anchor - throwing and orientation - adjusting mooring points, a buoy anchor seat and multiple lifting anchor seats; the anchor - throwing and orientation - adjusting mooring points are used to adjust the attitude of the gravity anchor during the lowering process, and the anchor - throwing and orientation - adjusting mooring points are located outside the lifting anchor seats; the buoy anchor seat is used to connect the buoy, and the buoy anchor seat is located between two of the anchor - throwing and orientation - adjusting mooring points; the lifting anchor seats are used to connect with the steel wire ropes.
6. The underwater gravity anchor relay type lowering system according to claim 5, wherein The gravity anchor is provided with an exhaust hole extending in the vertical direction and penetrating the gravity anchor; one end of the bottom surface of the gravity anchor has a tooth block formed by welding steel plates; a slope is provided between the top surface of the gravity anchor and the tooth block, and a cable anchor seat is arranged on the slope for providing positioning and anchoring force for the construction ship after connecting the cable.
7. The underwater gravity anchor relay type lowering system according to claim 4, characterized in that The floating crane is provided with a lifting device, and a hook is fixed at the end of the lifting device. The hook includes a double hook in an inverted T shape.
8. The underwater gravity anchor relay type lowering system according to claim 7, characterized in that, The hook includes a main hook and a sub-hook. The main hook of the floating crane lifts the gravity anchor through the steel wire rope.
9. The underwater gravity anchor relay type lowering system according to claim 4, characterized in that, The steel wire rope is a spiral steel wire bundle formed by twisting steel wires according to a predetermined rule, and the length of each steel wire rope is less than the maximum lifting height of the floating crane.
10. The underwater gravity anchor relay type lowering system according to claim 4, wherein, The water depth of the temporary working area is equal to the sea level elevation minus the seabed elevation; the water depths of multiple temporary working areas increase in sequence; the multiple temporary working areas are sorted in ascending order of water depth. The water depth of the nth temporary working area is greater than (n - 1) times the maximum lifting height of the floating crane and less than n times the maximum lifting height of the floating crane; where n is an integer greater than 0.
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