Large steel caissons with water-air combined controlled sinking and their sinking construction method

Abstract

This application discloses a large steel caisson with water-air combined controlled sinking and its sinking construction method. The steel caisson includes an outer caisson wall, an inner caisson wall, a top platform, and a pressurization and buoyancy-aiding mechanism. The outer caisson wall has an outer wall surface and an inner wall surface, extending along a first direction. The inner caisson wall is located inside the inner wall surface and extends along the first direction. The inner caisson wall includes a first caisson wall, a second caisson wall, and a third caisson wall. A portion of the inner wall surface, two portions of the first caisson wall, and a portion of the second caisson wall together form a first caisson. A portion of the second caisson wall and two portions of the third caisson wall together form a second caisson, and multiple second caissons are evenly distributed circumferentially. The top platform is fixed to the first end of the outer caisson wall, and the third end is at a predetermined distance from the top platform. The pressurization and buoyancy-aiding mechanism includes a buoyancy-aiding plate and an air compressor. The buoyancy-aiding plate is located inside the first caisson and is positioned close to the top platform. The bottom end of the first caisson is connected to seawater, and the top end is sealed by the buoyancy-aiding plate. The air compressor is connected to the first caisson and is used to control the air pressure inside the first caisson.

Description

Technical Field

[0001] This specification relates to the field of deep-water foundation construction technology for long-span bridges, and in particular to a large steel caisson with water-air combined controlled sinking and its sinking construction method. Background Technology

[0002] With the advancement of technology, the development of long-span bridges worldwide has been rapid, with their numbers constantly increasing and spans continuously breaking records. Caisson foundations are characterized by high load-bearing capacity, high rigidity, good stability, strong seismic resistance, no need for maintenance or protection, and reliable construction. They can be sunk to a deep, ideal base layer or directly placed on the foundation bed to obtain the required load-bearing capacity. Therefore, they are increasingly being used in the deep-water foundations of long-span bridges.

[0003] Steel caissons often feature an open top design. Because the foundation is located at the top of the caisson, there is usually a certain height difference between the outer and inner walls. When the steel caisson is floated into place and then submerged until the sea level covers the top surface of the inner wall, if the bottom of the caisson has not yet made contact with the seabed, continued submersion will cause seawater to rush into the caisson from the top surface of the inner compartment wall, leading to uncontrolled sinking of the caisson.

[0004] To prevent uncontrolled sinking of the caisson, a sealing plate needs to be installed on the top surface of the inner wall of the caisson. This plate can then be removed underwater during the later pouring of the bottom sealing concrete and the concrete within the compartments. Alternatively, the inner compartment walls can be raised to be flush with the outer compartment walls, and then removed underwater during the construction of the foundation. Regardless of the method used, this involves numerous temporary structures and underwater operations, creating many unfavorable factors for on-site construction organization and increasing construction costs and time. Summary of the Invention

[0005] In view of the shortcomings of the prior art, one object of this specification is to provide a large steel caisson with water-air combined controlled sinking and its sinking construction method, which can solve the problem of seawater rushing into the caisson wall from the top surface during the sinking of a large steel caisson without adding a large number of temporary structures or underwater operations, causing the caisson to sink uncontrollably.

[0006] To achieve the above objectives, this specification provides a large steel caisson with water-air combined controlled sinking, comprising:

[0007] An outer well wall having an outer wall surface and an inner wall surface extending along a first direction, the outer well wall having a first end and a second end opposite to each other along the first direction;

[0008] An inner well wall extending along the first direction, located inside the inner wall surface, has opposing third and fourth ends along the first direction; the inner well wall includes a first well wall, a second well wall, and a third well wall, with a plurality of first well walls evenly distributed circumferentially, one end of the first well wall connected to the inner wall surface in the radial direction, and the other end connected to the second well wall; the central axis of the second well wall and the central axis of the outer well wall are collinear; one end of the plurality of third well walls is connected to the second well wall in the radial direction, and the other end intersects the central axis of the outer well wall; a portion of the inner wall surface, two first well walls, and a portion of the second well wall together form a first well shaft, with a plurality of first well shafts evenly distributed circumferentially; a portion of the second well wall and two third well walls together form a second well shaft, with a plurality of second well shafts evenly distributed circumferentially, and the first well shaft is located outside the second well shaft;

[0009] A top platform is fixed to the first end of the outer well wall, and the third end of the inner well wall is located on the side of the top platform near the second end, and the third end and the top platform have a predetermined distance;

[0010] The pressurized buoyancy mechanism includes a buoyancy plate and an air compressor. The buoyancy plate is located inside the first wellbore and is positioned close to the top platform. The end of the first wellbore away from the top platform is connected to seawater, and the end of the first wellbore close to the top platform is sealed by the buoyancy plate. The two ends of the second wellbore, which are opposite to each other along the first direction, are both connected to seawater. The air compressor is positioned on the top platform and connected to the first wellbore, and is used to control the air pressure inside the first wellbore.

[0011] In a preferred embodiment, both the outer well wall and the second well wall are circular double-wall structures. The inner and outer walls of the outer well wall are reinforced by steel trusses and longitudinal and transverse ring plates. The inner well wall is also a double-wall structure, with the interior of the double walls reinforced by steel trusses and longitudinal and transverse ring plates.

[0012] In a preferred embodiment, the predetermined spacing is 7m.

[0013] In a preferred embodiment, the number of first well casings is equal to the number of first well walls, and the number of second well casings is equal to the number of third well walls; the number of first well walls is 16, and the number of third well walls is 4.

[0014] In a preferred embodiment, a support column for supporting the top platform is provided between the top platform and the inner well wall.

[0015] In a preferred embodiment, the top platform is provided with a base for mounting the air compressor, and the base is fixed to the top platform by welding; the air compressor is provided with an air valve for controlling the intake or exhaust of the first well shaft, and the air valve and the first well shaft are connected by a pipeline.

[0016] In a preferred embodiment, one air compressor controls the air pressure in two adjacent first wells, and each air compressor is controlled independently; the pipes of the two adjacent first wells sharing one air compressor are arranged in series.

[0017] This specification also provides a method for sinking a large steel caisson using a water-air combined controlled sinking method, comprising the following steps:

[0018] Step 1: The steel caisson is floated and positioned; the steel caisson is a large steel caisson with water-air combined controlled sinking as described in any one of claims 1-7;

[0019] Step 2: Sink the steel caisson by injecting water; during the water injection process, first inject water into the inner wall of the caisson, and then inject water into the outer wall of the caisson;

[0020] Step 3: When the steel caisson continues to sink until the sea level is about to cover the top surface of the inner well wall, determine whether the inner well wall is full of water; if not, stop filling the water, start the air compressor to pressurize and drain the water in the first well barrel, so that the steel caisson floats up, and repeat step 2 above; if yes, proceed to step 4.

[0021] Step 4: The steel caisson is depressurized and lowered, and the verticality of the steel caisson is monitored at the same time. The verticality of the steel caisson is adjusted by controlling the unbalanced air pressure.

[0022] Step 5: Steel caisson placement;

[0023] Steps 1, 2, and 3 are water injection control stages, while steps 4 and 5 are air pressure control stages.

[0024] In a preferred embodiment, in step 2, the water level difference between the outer well wall and the inner well wall is 14m.

[0025] In a preferred embodiment, in step 5, the planar position of the steel caisson is precisely positioned using an anchor cable system, a window period is selected, and the steel caisson is brought to the ground to complete the sinking control of the steel caisson. The anchor cable system includes a gravity anchor and a cable, with the gravity anchor fixed to the steel caisson via the cable. The cable can constrain the planar position of the steel caisson and is used to correct the planar position of the steel caisson during the sinking process. Beneficial effects

[0026] The large steel caisson with water-air combined controlled sinking provided in this embodiment is equipped with an outer well wall, an inner well wall, a top platform, and a pressurization and buoyancy mechanism. The air compressor in the pressurization and buoyancy mechanism can control the air pressure in the first well barrel and adjust the water level in the first well barrel, thereby adjusting the draft of the steel caisson. When the steel caisson continues to sink until the sea level is about to submerge the top surface of the inner well wall, and the inner well wall is not full of water, the water injection into the steel caisson is stopped, the air compressor is started to pressurize and drain the water in the first well barrel, causing the steel caisson to float, so that seawater will not rush into the well wall from the top surface. Then the water injection into the steel caisson continues. After the inner well wall is full of water, the air compressor is started to depressurize and sink the steel caisson, finally allowing the steel caisson to land on the seabed. This large steel caisson with water-air combined controlled sinking can solve the problem of seawater rushing into the well wall from the top surface during the sinking of a large steel caisson, causing uncontrolled sinking of the caisson, without adding a large number of temporary structures or underwater operations.

[0027] Specific embodiments of the present invention are disclosed in detail with reference to the following description and accompanying drawings, indicating how the principles of the invention can be employed. It should be understood that the embodiments of the present invention are not limited in scope as a result.

[0028] Features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0029] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, or components. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a flowchart illustrating the steps of a method for sinking a large steel caisson using a water-air combined controlled sinking technique, as provided in this embodiment.

[0032] Figure 2 This is a top view of a large steel caisson with water-air combined controlled sinking provided in this embodiment.

[0033] Figure 3 This is a cross-sectional view of a large steel caisson with water-air combined controlled sinking provided in this embodiment.

[0034] Figures 4 to 10 This diagram illustrates the sinking process of a large steel caisson controlled by a combination of water and air in this embodiment.

[0035] Explanation of reference numerals in the attached figures:

[0036] 100. Steel caisson; 1. Outer caisson wall; 11. Outer wall surface; 12. Inner wall surface; 13. First end; 14. Second end; 2. Inner caisson wall; 21. Third end; 22. Fourth end; 23. First caisson wall; 24. Second caisson wall; 25. Third caisson wall; 3. Buoyancy plate; 4. Top platform; 5. Support column; 6. First shaft; 7. Second shaft; 8. Base; 9. Air compressor; 10. Air valve; 15. Pipeline; 16. Sea level; 17. Seabed surface; 18. Foundation trench; 19. Gravity anchor; 20. Cable; X, First direction. Detailed Implementation

[0037] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0038] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or may be interposed with another element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or may be interposed with another element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementations.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0040] Please see Figure 2 and Figure 3 This application provides a large steel caisson 100 with water-air combined controlled sinking, including an outer well wall 1, an inner well wall 2, a top platform 4, and a pressurization and buoyancy aid mechanism.

[0041] The outer well wall 1 has an outer wall surface 11 and an inner wall surface 12, and extends along a first direction X. The outer well wall 1 has a first end 13 and a second end 14 opposite each other along the first direction X. Figure 3 As shown, the first direction X is preferably vertical, the first end 13 is the top of the outer well wall 1, and the second end 14 is the bottom of the outer well wall 1.

[0042] The inner well wall 2 is located inside the inner wall surface 12 and extends along the first direction X. The inner well wall 2 has a third end 21 and a fourth end 22 opposite to each other along the first direction X. The third end 21 is the top end of the inner well wall 2, and the fourth end 22 is the bottom end of the inner well wall 2. The inner well wall 2 includes a first well wall 23, a second well wall 24, and a third well wall 25. A plurality of first well walls 23 are evenly distributed circumferentially. One end of the first well wall 23 is connected to the inner wall surface 12 in the radial direction, and the other end is connected to the second well wall 24. The central axis of the second well wall 24 is collinear with the central axis of the outer well wall 1. One end of the plurality of third well walls 25 is connected to the second well wall 24 in the radial direction, and the other end intersects the central axis of the outer well wall 1. A portion of the inner wall surface 12, a portion of the two first well walls 23, and a portion of the second well wall 24 together form a first well shaft 6. A plurality of first well shafts 6 are evenly distributed circumferentially. A portion of the second well wall 24 and the two third well walls 25 together form the second wellbore 7. Multiple second wellbores 7 are evenly distributed circumferentially. The first wellbore 6 is located outside the second wellbores 7. The size of a single first wellbore 6 is smaller than the size of a single second wellbore 7, facilitating subsequent control of the gas pressure within the first wellbore 6.

[0043] The top platform 4 is fixed to the first end 13 (top) of the outer well wall 1 and is used to store necessary construction equipment and provide a space for personnel movement. The third end 21 of the inner well wall 2 is located on the side of the top platform 4 near the second end 14, and the third end 21 has a predetermined distance from the top platform 4, that is, the third end 21 is lower than the first end 13. In addition, the fourth end 22 of the first well wall 23 and the second well wall 24 can be flush with the second end 14, and the fourth end 22 of the third well wall 25 can be higher than the second end 14. That is, in the first direction X, neither end of the inner well wall 2 extends beyond the two ends of the outer well wall 1.

[0044] The pressurized buoyancy mechanism includes a buoyancy plate 3 and an air compressor 9. The buoyancy plate 3 is located inside the first shaft 6 and near the top platform 4. Preferably, the buoyancy plate 3 is located at the top of the first shaft 6 and is mainly used for buoyancy assistance during the undocking and floating process of the steel caisson 100, as well as for controlling the sinking process. The end of the first shaft 6 away from the top platform 4 (bottom end) is connected to seawater, and the end of the first shaft 6 near the top platform 4 (top end) is sealed by the buoyancy plate 3. The two ends of the second shaft 7 along the first direction X are both connected to seawater, that is, the top and bottom ends of the second shaft 7 are open, and the internal water level is the same as the sea level 16. The air compressor 9 is located on the top platform 4 and connected to the first shaft 6, and is used to control the air pressure inside the first shaft 6, thereby achieving the requirement of adjusting the draft of the steel caisson 100.

[0045] Without pressurization and venting, the water level inside the first shaft 6 is the same as the sea level 16. During the unloading and floating of the steel caisson 100, the air compressor 9 can be used to pressurize and drain the water according to the required draft, creating a height difference between the water level inside the first shaft 6 and the external sea level 16, thereby adjusting the draft of the steel caisson 100. In the second stage of the positioning and sinking of the steel caisson 100 (i.e., the air pressure control stage described below), the landing of the steel caisson 100 and the correction of its verticality are achieved by controlling the air pressure inside the first shaft 6.

[0046] The large steel caisson 100 with water-air combined controlled sinking provided in this embodiment is equipped with an outer well wall 1, an inner well wall 2, a top platform 4, and a pressurization and buoyancy mechanism. The air compressor 9 in the pressurization and buoyancy mechanism can control the air pressure in the first well barrel 6 and adjust the water level in the first well barrel 6, thereby adjusting the draft of the steel caisson 100. When the steel caisson 100 continues to sink until the sea level 16 is about to submerge the top surface of the inner well wall 2, the water in the inner well wall 2 is not full. Water injection into the steel caisson 100 is stopped, and the air compressor 9 is started to pressurize and drain the water in the first well barrel 6, causing the steel caisson 100 to float. This prevents seawater from rushing into the well wall from the top surface. Then, water injection into the steel caisson 100 is resumed. After the water in the inner well wall 2 is full, the air compressor 9 is started to depressurize and sink the steel caisson 100, finally allowing the steel caisson 100 to land on the seabed. The water-air combined controlled sinking large steel caisson 100 can solve the problem of seawater rushing into the caisson wall from the top surface during the sinking process without adding a large number of temporary structures or engaging in underwater operations, thus preventing the caisson from sinking uncontrollably.

[0047] In this embodiment, both the outer well wall 1 and the second well wall 24 are annular double-wall structures. The inner wall surface 12 and the outer wall surface 11 of the outer well wall 1 are stiffened by steel trusses and longitudinal and transverse ring plates. The inner well wall 2 is a double-wall structure, and the interior of the double walls of the inner well wall 2 is stiffened by steel trusses and longitudinal and transverse ring plates. The predetermined distance between the third end 21 of the inner well wall 2 and the top platform 4 is 7m.

[0048] In this embodiment, the number of first well casings 6 is equal to the number of first well walls 23, and the number of second well casings 7 is equal to the number of third well walls 25. The number of first well walls 23 can be 16, and the number of third well walls 25 can be 4.

[0049] Specifically, a support column 5 is provided between the top platform 4 and the inner well wall 2 to support the top platform 4.

[0050] like Figure 2 and Figure 3 As shown, the top platform 4 is provided with a base 8 for mounting the air compressor 9. The base 8 is fixed to the top platform 4 by welding and provides support for the air compressor 9. The air compressor 9 can be fixed to the base 8 by fasteners. The air compressor 9 is equipped with a matching air valve 10 for controlling the intake or exhaust of air into the first shaft 6, thereby controlling the air pressure inside the first shaft 6. The air valve 10 and the first shaft 6 are connected by a pipe 15. Gas is supplied through the pipe 15, one end of which is connected to the air valve 10, and the other end is connected to the first shaft 6.

[0051] In this embodiment, the air compressor 9 adopts a one-to-two configuration, that is, one air compressor 9 controls the air pressure in two adjacent first shafts 6. Each air compressor 9 is independently controlled. In the second stage of the positioning and sinking of the steel caisson 100 (i.e., the air pressure control stage described below), the vertical correction purpose can be achieved by controlling the unbalanced air pressure. Figure 2 As shown, the pipes 15 of two adjacent first wellbore 6 sharing one air compressor 9 are arranged in series.

[0052] like Figure 1 As shown in the figure, this application also provides a method for sinking a large steel caisson 100 using a water-air combined controlled sinking method, including the following steps:

[0053] Step 1: The steel caisson 100 is floated into position. The steel caisson 100 is a large steel caisson with water-air combined controlled sinking as described in any of the above embodiments. Specifically, after the steel caisson 100 is undocking, it is towed by tugboats, floated into position, and secured with cables. A positioning device is used to roughly position the steel caisson 100, such as... Figure 4 As shown.

[0054] Step 2: The steel caisson 100 is then lowered by water injection. During the water injection process, water is first injected into the inner wall 2. Simultaneously, to meet the head difference requirement between the inner and outer walls of the steel caisson 100 (the water level difference between the outer wall 1 and the inner wall 2 is approximately 14m), water is then injected into the outer wall 1 to ensure structural safety. Figure 5 As shown.

[0055] Step 3: As the steel caisson 100 continues to sink until the sea level 16 is about to submerge the top surface of the inner well wall 2, determine whether the inner well wall 2 is full of water. If not, to prevent seawater from entering the inner well wall 2 and causing uncontrollable sudden sinking of the steel caisson 100, stop water injection, start the air compressor 9, and pressurize and drain the water from the first well shaft 6 to make the steel caisson 100 float. Figure 6 As shown, repeat step 2 above (i.e., after the steel caisson 100 floats up, fill the inner well wall 2 with water again to make the steel caisson 100 sink until the inner well wall 2 is filled with water, as shown). Figure 7 (As shown). If so, proceed to step 4.

[0056] Step 4: The steel caisson 100 is depressurized and lowered, while its verticality is monitored and adjusted using unbalanced air pressure control. For example... Figure 8 As shown, the steel caisson 100 tilts under the action of wave current force. At this time, the verticality of the steel caisson 100 is adjusted by the unbalanced pressurization method, as follows. Figure 9 As shown. Unbalanced air pressure control or unbalanced pressurization method is achieved by independently controlling each air compressor 9. That is, different air compressors 9 can adjust the air pressure of the first wellbore 6 at different locations to different values, thereby adjusting the inclined steel caisson 100 to a vertical position.

[0057] Step 5: The steel caisson is placed on the bed at 100mm. Specifically, as follows... Figure 10 As shown, the steel caisson 100 is precisely positioned in planar terms using an anchor cable system. A suitable window of opportunity is selected to allow the steel caisson 100 to land, thus controlling its sinking. The anchor cable system includes a gravity anchor 19 and a cable 20, serving as a positioning device for the steel caisson 100. The gravity anchor 19 is fixed to the steel caisson 100 via the cable 20, providing anchoring force for the positioning device. The cable 20 constrains the planar position of the steel caisson 100, correcting its position during sinking.

[0058] Steps 1, 2, and 3 constitute the water injection control stage (first stage), while steps 4 and 5 constitute the gas pressure control stage (second stage). The transition from the water injection control stage to the gas pressure control stage is marked by the completion of water injection into the second wellbore 7.

[0059] During the initial water injection and sinking of the steel caisson 100, priority is given to injecting water into the inner well wall 2, while the water injection into the outer well wall 1 is based on ensuring a head difference of approximately 14m between the inner and outer walls. When the steel caisson 100 is sinking to the point where the sea surface is about to submerge the top surface of the inner well wall 2, the air compressor 9 is activated to make the steel caisson 100 float. After reaching the set position, water injection and sinking of the steel caisson 100 continues until the inner well wall 2 is filled with water. At this point, the system transition is completed, and the system enters the air pressure control stage.

[0060] The steel caisson 100 is depressurized and lowered into the bed using air compressor 9, while its sinking attitude is monitored. Uneven air pressure is used to correct the verticality of the steel caisson 100. Simultaneously, the horizontal position of the steel caisson 100 is precisely located using an anchor cable system, and a suitable window of opportunity is selected to allow the caisson to land, thus completing the sinking control of the steel caisson 100.

[0061] In this embodiment, the construction method can solve the technical problems of the large steel caisson 100 with water-air combined controlled sinking, and achieve the technical effect of the large steel caisson 100 with water-air combined controlled sinking. The specific details will not be repeated here.

[0062] In this embodiment, sea level 16 refers to the sea surface level, which is assumed to be the high-tide sea level 16 under unfavorable working conditions. The steel caisson 100 is lowered so that the second end 14 of the outer caisson wall 1 and the fourth end 22 of the inner caisson wall 2 are placed in the trench 18 of the seabed surface 17. The seabed surface 17 is the seabed base, which in this embodiment is bare rock, but bases with overburden layers can also be used. The trench 18 is the placement point of the steel caisson 100 on the seabed, and is pre-treated into a ring-shaped trench through processes such as seabed blasting and slag removal.

[0063] It should be noted that in the description of this specification, the terms "first," "second," etc., are used only for descriptive purposes and to distinguish similar objects; there is no order between them, nor should they be construed as indicating or implying relative importance. Furthermore, in the description of this specification, unless otherwise stated, "a plurality of" means two or more.

[0064] Any numerical values ​​cited herein include all values ​​ranging from a lower limit to an upper limit, increasing by one unit, with at least two units between any lower and any higher value. For example, if the quantity of a component or the value of a process variable (e.g., temperature, pressure, time, etc.) is described as being from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, the purpose is to illustrate that values ​​such as 15 to 85, 22 to 68, 43 to 51, 30 to 32 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, etc. These are merely examples intended for explicit expression, and it can be assumed that all possible combinations of values ​​listed between the minimum and maximum values ​​are explicitly described in this specification in a similar manner.

[0065] Unless otherwise stated, all ranges include the endpoints and all numbers between them. The terms "approximately" or "about" used with ranges apply to both endpoints of the range. Thus, "approximately 20 to 30" is intended to cover "approximately 20 to approximately 30," including at least the specified endpoints.

[0066] All articles and references disclosed herein, including patent applications and publications, are incorporated herein by reference for various purposes. The term “substantially constitutes…” used to describe a combination should include the identified elements, components, parts, or steps, as well as other elements, components, parts, or steps that do not substantially affect the essential novelty of the combination. The use of the terms “comprising” or “including” to describe combinations of elements, components, parts, or steps herein also contemplates embodiments substantially constituted by such elements, components, parts, or steps. The use of the term “may” herein is intended to indicate that any described attribute included by “may” is optional.

[0067] Multiple elements, components, parts, or steps can be provided by a single integrated element, component, part, or step. Alternatively, a single integrated element, component, part, or step can be divided into multiple separate elements, components, parts, or steps. The use of "a" or "an" to describe an element, component, part, or step does not imply the exclusion of other elements, components, parts, or steps.

[0068] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this teaching should not be determined by reference to the above description, but rather by reference to the appended claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the inventors have not considered that subject matter as part of the disclosed inventive subject matter.

Claims

1. A method for sinking a large steel caisson using a water-air combined controlled sinking system, characterized in that, The steel caisson includes: An outer well wall having an outer wall surface and an inner wall surface extending along a first direction, the outer well wall having a first end and a second end opposite to each other along the first direction; An inner well wall extending along the first direction, located inside the inner wall surface, has opposing third and fourth ends along the first direction; the inner well wall includes a first well wall, a second well wall, and a third well wall, with a plurality of first well walls evenly distributed circumferentially, one end of the first well wall connected to the inner wall surface in the radial direction, and the other end connected to the second well wall; the central axis of the second well wall and the central axis of the outer well wall are collinear; one end of the plurality of third well walls is connected to the second well wall in the radial direction, and the other end intersects the central axis of the outer well wall; a portion of the inner wall surface, two first well walls, and a portion of the second well wall together form a first well shaft, with a plurality of first well shafts evenly distributed circumferentially; a portion of the second well wall and two third well walls together form a second well shaft, with a plurality of second well shafts evenly distributed circumferentially, and the first well shaft is located outside the second well shaft; A top platform is fixed to the first end of the outer well wall, and the third end of the inner well wall is located on the side of the top platform near the second end, and the third end and the top platform have a predetermined distance; The pressurized buoyancy mechanism includes a buoyancy plate and an air compressor. The buoyancy plate is located inside the first wellbore and is positioned close to the top platform. The end of the first wellbore away from the top platform is connected to seawater, and the end of the first wellbore close to the top platform is sealed by the buoyancy plate. The second wellbore has both ends connected to seawater along the first direction. The air compressor is positioned on the top platform and connected to the first wellbore, and is used to control the air pressure inside the first wellbore. The sinking construction method for the large steel caisson controlled by the water-air combination includes the following steps: Step 1: The steel caisson is floated into place; Step 2: Sink the steel caisson by injecting water; during the water injection process, first inject water into the inner well wall, and then inject water into the outer well wall; Step 3: When the steel caisson continues to sink until the sea level is about to submerge the top surface of the inner well wall, determine whether the inner well wall is full of water; if not, stop water injection, start the air compressor to pressurize and drain the water in the first well barrel, so that the steel caisson floats up, and repeat Step 2 above; if yes, proceed to Step 4. Step 4: The steel caisson is depressurized and sunk, and the verticality of the steel caisson is monitored. The verticality of the steel caisson is adjusted by unbalanced air pressure control. Step 5: The steel caisson is placed on the bed; Steps 1, 2, and 3 are water injection control stages, while steps 4 and 5 are air pressure control stages.

2. The sinking construction method for a large steel caisson using a water-air combined controlled sinking method according to claim 1, characterized in that, Both the outer well wall and the second well wall are circular double-wall structures. The inner and outer walls of the outer well wall are reinforced by steel trusses and longitudinal and transverse ring plates. The inner well wall is also a double-wall structure, with the inner walls reinforced by steel trusses and longitudinal and transverse ring plates.

3. The sinking construction method for a large steel caisson using a water-air combined controlled sinking method according to claim 1, characterized in that, The predetermined spacing is 7m.

4. The sinking construction method for a large steel caisson using a water-air combined controlled sinking method according to claim 1, characterized in that, The number of first well casings is equal to the number of first well walls, and the number of second well casings is equal to the number of third well walls; the number of first well walls is 16, and the number of third well walls is 4.

5. The sinking construction method for a large steel caisson using a water-air combined controlled sinking method according to claim 1, characterized in that, A support column for supporting the top platform is provided between the top platform and the inner well wall.

6. The sinking construction method for a large steel caisson using a water-air combined controlled sinking method according to claim 1, characterized in that, The top platform is provided with a base for mounting the air compressor, and the base is fixed to the top platform by welding; the air compressor is provided with an air valve for controlling the intake or exhaust of the first well shaft, and the air valve and the first well shaft are connected by a pipeline.

7. The sinking construction method for a large steel caisson using a water-air combined controlled sinking method according to claim 6, characterized in that, One of the air compressors controls the air pressure in two adjacent first wells, and each air compressor is controlled independently; the pipes of the two adjacent first wells that share one air compressor are arranged in series.

8. The sinking construction method for a large steel caisson using a water-air combined controlled sinking method according to claim 1, characterized in that, In step 2, the water level difference between the outer well wall and the inner well wall is 14m.

9. The sinking construction method for a large steel caisson using a water-air combined controlled sinking method according to claim 1, characterized in that, In step 5, the planar position of the steel caisson is precisely positioned using an anchor cable system, and a window period is selected to allow the steel caisson to land, thus completing the sinking control of the steel caisson. The anchor cable system includes a gravity anchor and a cable, with the gravity anchor fixed to the steel caisson via the cable. The cable can constrain the planar position of the steel caisson and is used to correct its position during the sinking process.

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