Prefabricated assembled open caisson, open caisson shaft assembling method and open caisson bottom sealing method

Abstract

The invention belongs to the technical field of open caissons, and discloses a prefabricated assembly type open caisson, an open caisson shaft assembly method and an open caisson bottom sealing method. The prefabricated open caisson comprises a fore shaft ring beam, a shaft and a bottom sealing layer, wherein the fore shaft ring beam is connected with the ground; the shaft comprises a blade foot ring, a connecting ring, a plurality of standard rings and a fore shaft ring which are sequentially connected from bottom to top, the blade foot ring is used for cutting a soil body and sinking to the ground, and the fore shaft ring is connected with a fore shaft ring beam; the bottom sealing layer comprises a first annular piece, a second annular piece and a circular bottom sealing piece which are sequentially connected from outside to inside, the outer ring of the first annular piece is connected with the inner ring of the connecting ring, and the first annular piece is formed by sequentially connecting a plurality of first fan-shaped connecting parts in the annular direction; and the second annular piece is formed by sequentially connecting a plurality of second fan-shaped connecting parts in the annular direction, and the first fan-shaped connecting parts and the second fan-shaped connecting parts are connected in a staggered joint mode, so that the bottom sealing layer is constructed to be of a bowl-shaped structure, the construction period can be shortened, the project quality can be improved, and the safety risk can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of caissons, and in particular to a prefabricated assembled caisson, a caisson shaft assembly method and a caisson bottom sealing method. Background Art

[0002] The caisson method often uses a cast-in-place reinforced concrete structure with a circular cross-section. It has the advantages of good stress-bearing and waterproof performance, strong support capacity, high space utilization and low cost. The construction method can be selected according to the stratum and groundwater conditions, and the undrained method has little impact on the surrounding environment.

[0003] Currently, caisson construction requires section-by-section casting and soil excavation for sinking. Each section requires a steel cage, formwork, and concrete pouring and curing to achieve full strength before sinking. Once fully sunk, a bottom seal reinforcement mesh must be constructed and concrete poured. The undrained construction method requires pouring underwater plain concrete to seal the bottom. Once the seal reaches full strength, the accumulated water is drained and the seal is constructed, severely restricting the construction schedule. Furthermore, traditional shaft seals are often flat. Under the influence of groundwater pressure or foundation reaction, the cross-sectional bending moment and shear force are large, resulting in thick seals, large reinforcement requirements, and increased costs. Overly dense reinforcement also affects concrete pouring and vibration, making construction quality difficult to guarantee.

[0004] Therefore, there is an urgent need for prefabricated assembled caissons, caisson shaft assembly methods and caisson bottom sealing methods to solve the above problems. Summary of the Invention

[0005] The first purpose of the present invention is to provide a prefabricated assembled caisson, improve the standardization, factory production and mechanization of caisson construction, shorten the construction period, reduce the project cost, improve the project quality and reduce safety risks.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] Prefabricated caisson, including:

[0008] Locking ring beam, connected to the ground;

[0009] The shaft comprises a cutting edge ring, a connecting ring, a plurality of standard rings and a locking ring connected in sequence from bottom to top, wherein the cutting edge ring is used to cut the soil and sink below the ground, and the locking ring is connected to the locking ring beam;

[0010] The bottom sealing layer comprises a first annular member, a second annular member and a circular bottom sealing member which are sequentially connected from the outside to the inside, wherein the outer ring of the first annular member is connected to the inner ring of the connecting ring, and the first annular member is formed by a plurality of first fan-shaped connecting parts which are sequentially connected along the circumferential direction; the second annular member is formed by a plurality of second fan-shaped connecting parts which are sequentially connected along the circumferential direction, and the first fan-shaped connecting parts and the second fan-shaped connecting parts are connected with staggered seams so that the bottom sealing layer is constructed into a bowl-shaped structure.

[0011] As an optional solution for a prefabricated assembled caisson, a grouting hole is provided on the first fan-shaped connecting portion; and / or a grouting hole is provided on the second fan-shaped connecting portion; and / or a grouting hole is provided on the circular bottom cover, and the grouting hole is used for grouting.

[0012] As an optional solution for a prefabricated assembled caisson, the prefabricated assembled caisson also includes a first oblique bolt, a first groove is provided on the connecting ring, the outer ring edge of the first fan-shaped connecting part is plugged into the first groove, and the first fan-shaped connecting part is connected to the connecting ring through the first oblique bolt.

[0013] As an optional solution of a prefabricated assembled caisson, the prefabricated assembled caisson further includes a second oblique bolt, any two of the first fan-shaped connecting parts are connected by the second oblique bolt, any two of the second fan-shaped connecting parts are connected by the second oblique bolt, the first fan-shaped connecting part and the second fan-shaped connecting part are connected by the second oblique bolt, and the second fan-shaped connecting part and the circular bottom cover are connected by the second oblique bolt; or;

[0014] The prefabricated assembled caisson also includes a first bent bolt, any two of the first fan-shaped connecting parts are connected by the first bent bolt, any two of the second fan-shaped connecting parts are connected by the first bent bolt, the first fan-shaped connecting part and the second fan-shaped connecting part are connected by the first bent bolt, and the second fan-shaped connecting part and the circular bottom cover are connected by the first bent bolt.

[0015] As an optional solution for a prefabricated assembled caisson, the connection between any two of the first fan-shaped connecting parts, the connection between any two of the second fan-shaped connecting parts, the connection between the first fan-shaped connecting part and the second fan-shaped connecting part, and the connection between the second fan-shaped connecting part and the circular bottom cover are all provided with a sealing and waterproof structure.

[0016] As an optional solution for a prefabricated assembled caisson, the blade ring, the connecting ring, multiple standard rings and the locking ring are all annular structures. Each of the annular structures is formed by multiple pipe segments connected along the annular direction, and multiple pipe segments in the same annular structure are connected with staggered seams.

[0017] As an optional solution for a prefabricated caisson, the prefabricated caisson further includes longitudinal straight bolts, and two adjacent annular structures are connected by the longitudinal straight bolts.

[0018] As an optional solution for a prefabricated and assembled caisson, the prefabricated and assembled caisson also includes a straight bolt sleeve and a shear pin. The straight bolt sleeve is sleeved on the outside of the longitudinal straight bolt, and the shear pin is sleeved on the outside of the straight bolt sleeve and passes through the longitudinal joints of two adjacent pipe segments for transmitting shear force.

[0019] The second object of the present invention is to provide a caisson shaft assembly method, which is applied to the above-mentioned prefabricated assembled caisson, reduces the amount of on-site pouring, improves construction quality, ensures reliable structural connection, and ensures the overall stability of the caisson.

[0020] To achieve this object, the present invention adopts the following technical solutions:

[0021] A caisson shaft assembly method is applied to the above-mentioned prefabricated caisson, and the caisson shaft assembly method includes:

[0022] S1: The blade foot ring cuts the soil and removes the soil surrounded by the blade foot ring, so that the blade foot ring sinks below the ground;

[0023] S2: The connecting ring is connected to the blade foot ring, and the soil surrounded by the connecting ring and the blade foot ring is excavated to sink the connecting ring below the ground;

[0024] S3: The standard ring is connected to the connecting ring, and the soil surrounded by the standard ring, the connecting ring, and the blade ring is excavated. Multiple standard rings are connected one by one, and the stacking and sinking are repeated until the last standard ring is sunk below the ground.

[0025] S4: placing the locking ring in the locking ring beam, connecting it to the locking ring beam, and connecting the locking ring to the last standard ring.

[0026] The third object of the present invention is to provide a caisson bottom sealing method, which is applied to the above-mentioned prefabricated assembled caisson, has high construction efficiency, strong structural integrity, optimizes the stress of the sealing bottom layer, reduces the bending moment and shear force of the sealing bottom layer, and reduces costs.

[0027] To achieve this object, the present invention adopts the following technical solutions:

[0028] The caisson bottom sealing method is applied to the above-mentioned prefabricated caisson, and the caisson bottom sealing method includes:

[0029] S1: pouring bottom seal concrete in the wellbore, pumping out water in the wellbore after the bottom seal concrete reaches a preset strength, connecting the plurality of first fan-shaped connecting parts to the inner ring of the connecting ring one by one, and connecting the plurality of first fan-shaped connecting parts in sequence along the circumferential direction to form the first annular member;

[0030] S2: the second sector-shaped connecting parts are staggeredly connected to the first sector-shaped connecting parts one by one, and a plurality of the second sector-shaped connecting parts are sequentially connected along the annular direction to form the second annular member;

[0031] S3: The plurality of second fan-shaped connecting portions are all connected to the circular bottom cover, and the bottom cover is constructed into a bowl-shaped structure.

[0032] Beneficial effects:

[0033] The present invention provides a prefabricated assembled caisson. During the construction of the shaft, the blade foot ring cuts the soil and sinks. The blade foot ring, the connecting ring, the multiple standard rings and the locking ring are connected in sequence from bottom to top. The locking ring is connected to the locking ring beam to provide an anti-floating reaction force. During the construction of the bottom sealing layer, the outer ring of the first annular member is connected to the inner ring of the connecting ring. The multiple first fan-shaped connecting parts of the first annular member are circumferentially spliced. The multiple second fan-shaped connecting parts of the second annular member are circumferentially connected, and the second fan-shaped connecting parts are staggered with the first fan-shaped connecting parts, and then connected to the circular bottom sealing member to form a bowl-shaped structure. The prefabricated assembled caisson enhances its integrity through staggered splicing. The bowl-shaped structure optimizes stress, reduces bending moment shear force under groundwater pressure, reduces the thickness and reinforcement amount of the bottom sealing layer, and saves costs. At the same time, the prefabricated construction improves efficiency, improves the standardization, factory production and mechanization of caisson construction, shortens the construction period, reduces project costs, improves project quality, and reduces safety risks.

[0034] The present invention provides a caisson shaft assembly method, which is applied to the above-mentioned prefabricated assembled caisson, wherein the blade foot ring cuts the soil and removes the soil surrounded by the blade foot ring so that the blade foot ring sinks below the ground; the connecting ring is connected to the blade foot ring, and the soil surrounded by the connecting ring and the blade foot ring is removed so that the connecting ring sinks below the ground; the standard ring is connected to the connecting ring, and the soil surrounded by the standard ring, the connecting ring and the blade foot ring is removed. Multiple standard rings are connected one by one, repeatedly stacked and sunk until the last standard ring sinks below the ground; the locking ring is placed in the locking ring beam and connected to the locking ring beam, and the locking ring is connected to the last standard ring. The caisson shaft assembly method adopts a construction method of connecting and sinking one by one, which can improve construction efficiency and shorten construction period. The assembly operation reduces the amount of on-site pouring and improves construction quality. The structural connection is reliable, ensuring the overall stability of the caisson.

[0035] The present invention provides a method for sealing the bottom of a caisson, which is applied to the above-mentioned prefabricated assembled caisson. The bottom concrete is poured in the shaft. After the bottom concrete reaches a preset strength, the water in the shaft is pumped out. The multiple first fan-shaped connecting parts are connected to the inner ring of the connecting ring one by one, and the multiple first fan-shaped connecting parts are connected in sequence along the circumferential direction to form a first annular part; the second fan-shaped connecting parts are staggered and connected to the first fan-shaped connecting parts one by one, and the multiple second fan-shaped connecting parts are connected in sequence along the circumferential direction to form a second annular part; the multiple second fan-shaped connecting parts are all connected to the circular bottom sealing part, and the bottom sealing layer is constructed into a bowl-shaped structure. The assembled bottom sealing construction adopted in the caisson bottom sealing method has high efficiency, the staggered connection enhances the integrity of the structure, the bowl-shaped structure optimizes the force, reduces the bending moment and shear force of the bottom sealing layer, reduces costs, and the bottom concrete is poured first and then the drainage construction is carried out, thereby ensuring safety and reducing the impact on the surrounding environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a cross-sectional view of a prefabricated caisson provided by an embodiment of the present invention;

[0037] Figure 2 This is a first schematic diagram of the bottom cover provided by an embodiment of the present invention;

[0038] Figure 3 This is a second schematic diagram of the bottom cover provided by an embodiment of the present invention;

[0039] Figure 4 is a schematic diagram of the connection between the first fan-shaped connecting portion and the connecting ring provided by an embodiment of the present invention;

[0040] Figure 5 This is a first schematic diagram of the connection of two first fan-shaped connecting parts provided by an embodiment of the present invention;

[0041] Figure 6 This is a second schematic diagram of the connection of two first fan-shaped connecting parts provided by an embodiment of the present invention;

[0042] Figure 7 is a first schematic diagram of a wellbore provided by an embodiment of the present invention;

[0043] Figure 8 is a second schematic diagram of a wellbore provided by an embodiment of the present invention;

[0044] Figure 9 is a first schematic diagram of a pipe segment provided by an embodiment of the present invention;

[0045] Figure 10 is a second schematic diagram of a pipe segment provided by an embodiment of the present invention;

[0046] Figure 11 is a schematic diagram of a plurality of pipe segments connected in the longitudinal direction according to an embodiment of the present invention;

[0047] Figure 12 is a schematic diagram of a straight bolt sleeve provided by an embodiment of the present invention;

[0048] Figure 13 is a schematic diagram of a scissor pin provided in an embodiment of the present invention;

[0049] Figure 14 This is a first schematic diagram of two segments connected in a circumferential direction according to an embodiment of the present invention;

[0050] Figure 15 This is a second schematic diagram of two pipe segments connected along the circumferential direction provided by an embodiment of the present invention.

[0051] In the picture:

[0052] 100, ground; 200, bottom seal concrete; 300, filling material; 400, bottom concrete; 1, locking ring beam; 11, tongue and groove;

[0053] 2. Wellbore; 201. Segment; 202. Longitudinal annular seam; 203. Circumferential segment seam;

[0054] 21. Blade foot ring; 211. Second groove;

[0055] 22. Connecting ring; 221. First groove;

[0056] 23, standard ring; 231, first ring; 232, Nth ring;

[0057] 24. Locking ring; 241. Rib;

[0058] 3. Sealing bottom layer; 301. Grouting hole; 302. Sectional joint;

[0059] 31. First annular member; 311. First fan-shaped connecting portion;

[0060] 32. Second annular member; 321. Second fan-shaped connecting portion;

[0061] 33. Round bottom cover;

[0062] 41. First oblique bolt; 42. Second oblique bolt; 43. Third oblique bolt;

[0063] 51. First bend bolt; 52. Second bend bolt;

[0064] 61. Longitudinal straight bolt; 62. Straight bolt sleeve; 621. Thread; 622. Septum; 63. Shear pin;

[0065] 71. Sealant; 72. Sealing ring; 73. Washer; 74. Rubber sheet; 75. Oblique bolt sleeve; 76. Sealing pad;

[0066] 8. Anti-floating piles. DETAILED DESCRIPTION

[0067] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0068] In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0069] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0070] In the description of this embodiment, the terms "upper," "lower," "right," and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely for ease of description and simplified operation. They do not indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meanings.

[0071] This embodiment discloses a prefabricated caisson, a caisson shaft assembly method, and a caisson bottom sealing method. Figure 1-Figure 3 As shown, the prefabricated assembled caisson includes a locking ring beam 1, a shaft 2 and a sealing layer 3, and the locking ring beam 1 is connected to the ground 100; the shaft 2 includes a blade ring 21, a connecting ring 22, multiple standard rings 23 and a locking ring 24 connected in sequence from bottom to top, the blade ring 21 is used to cut the soil and sink below the ground 100, and the locking ring 24 is connected to the locking ring beam 1; the sealing layer 3 includes a first ring member 31, a second ring member 32 and a circular bottom sealing member 33 connected in sequence from outside to inside, the outer ring of the first ring member 31 is connected to the inner ring of the connecting ring 22, and the first ring member 31 is formed by a plurality of first fan-shaped connecting parts 311 connected in sequence along the circumferential direction; the second ring member 32 is formed by a plurality of second fan-shaped connecting parts 321 connected in sequence along the circumferential direction, and the first fan-shaped connecting part 311 and the second fan-shaped connecting part 321 are connected by staggered seams, so that the sealing layer 3 is constructed into a bowl-shaped structure.

[0072] In the prefabricated assembled caisson disclosed in this embodiment, when the wellbore 2 is constructed, the blade ring 21 cuts the soil and sinks, and the blade ring 21, the connecting ring 22, multiple standard rings 23 and the locking ring 24 are connected in sequence from bottom to top, and the locking ring 24 is connected to the locking ring beam 1 to provide anti-floating reaction force; when the sealing bottom layer 3 is constructed, the outer ring of the first annular member 31 is connected to the inner ring of the connecting ring 22, the first annular member 31 is circumferentially spliced ​​by multiple first fan-shaped connecting parts 311, the second annular member 32 is circumferentially connected by multiple second fan-shaped connecting parts 321, and the second fan-shaped connecting parts 321 are staggeredly connected to the first fan-shaped connecting parts 311, and then connected to the circular bottom sealing member 33, together forming a bowl-shaped structure. The prefabricated and assembled caisson enhances its integrity through staggered splicing, and the bowl-shaped structure optimizes stress, reduces bending moment and shear force under groundwater pressure, reduces the thickness and reinforcement amount of the sealing layer 3, and saves costs. At the same time, the assembled construction improves efficiency, increases the standardization, factory production and mechanization of caisson construction, shortens the construction period, reduces project costs, improves project quality, and reduces safety risks.

[0073] This embodiment discloses a caisson shaft assembly method, which is applied to the prefabricated caisson in this embodiment. The caisson shaft assembly method includes:

[0074] S1: The blade foot ring 21 cuts the soil and removes the soil surrounded by the blade foot ring 21, so that the blade foot ring 21 sinks to below the ground 100;

[0075] S2: The connecting ring 22 is connected to the blade foot ring 21, and the soil surrounded by the connecting ring 22 and the blade foot ring 21 is excavated to make the connecting ring 22 sink to below the ground 100;

[0076] S3: The standard ring 23 is connected to the connecting ring 22, and the soil surrounded by the standard ring 23, the connecting ring 22 and the blade ring 21 is excavated. Multiple standard rings 23 are connected one by one, and the stacking and sinking are repeated until the last standard ring 23 sinks to 100 below the ground;

[0077] S4: Place the locking ring 24 in the locking ring beam 1 and connect it to the locking ring beam 1, and connect the locking ring 24 to the last standard ring 23.

[0078] The caisson shaft assembly method disclosed in this embodiment is applied to the above-mentioned prefabricated assembled caisson. After the blade foot ring 21 cuts the soil, the surrounding soil is excavated and the caisson is sunk to below 100° on the ground. The connecting ring 22 is connected to the blade foot ring 21, and the soil is excavated and the caisson is sunk. The standard ring 23 is connected to the connecting ring 22, and the soil is excavated. Multiple standard rings 23 are connected one by one, repeatedly stacked and sunk until the last standard ring 23 sinks to below 100° on the ground. Finally, the locking ring 24 is placed in the locking ring beam 1 and connected to it and the last standard ring 23. The caisson shaft assembly method adopts a construction method of connecting and sinking one by one, which can improve construction efficiency and shorten construction period. The assembly operation reduces the amount of on-site pouring and improves construction quality. The structural connection is reliable, ensuring the overall stability of the shaft 2.

[0079] In this embodiment, for the convenience of description, multiple standard rings 23 can be defined from bottom to top as the first ring 231 to the Nth ring 232. It can be understood that the first ring 231 is connected to the connecting ring 22, the first ring 231 to the Nth ring 232 are connected ring by ring, and the Nth ring 232 is connected to the locking ring 24.

[0080] This embodiment discloses a caisson bottom sealing method, which is applied to the prefabricated caisson in this embodiment. The caisson bottom sealing method includes:

[0081] S1: Casting bottom seal concrete 200 in the shaft 2. After the bottom seal concrete 200 reaches a predetermined strength, the water in the shaft 2 is pumped out. The plurality of first sector-shaped connecting portions 311 are connected one by one to the inner ring of the connecting ring 22. The plurality of first sector-shaped connecting portions 311 are sequentially connected along the annular direction to form a first annular member 31.

[0082] S2: The second sector-shaped connecting parts 321 are staggeredly connected to the first sector-shaped connecting parts 311 one by one, and the plurality of second sector-shaped connecting parts 321 are sequentially connected along the annular direction to form a second annular member 32;

[0083] S3: The plurality of second fan-shaped connecting portions 321 are all connected to the circular bottom cover 33 , and the bottom cover 3 is constructed into a bowl-shaped structure.

[0084] The caisson bottom sealing method disclosed in this embodiment is applied to the above-mentioned prefabricated assembled caisson. The bottom sealing concrete 200 is poured in the shaft 2. After the bottom sealing concrete 200 reaches the preset strength, the water is pumped out. First, multiple first fan-shaped connecting parts 311 are connected to the inner ring of the connecting ring 22 one by one, and are sequentially spliced ​​along the circumferential direction to form a first annular member 31. Then, the second fan-shaped connecting parts 321 are staggered and connected to the first fan-shaped connecting parts 311 one by one, and then spliced ​​along the circumferential direction to form a second annular member 32. Finally, multiple second fan-shaped connecting parts 321 are connected to the circular bottom sealing member 33. Through the above steps, the sealing layer 3 is constructed into a bowl-shaped structure. The assembled bottom sealing construction adopted in the caisson bottom sealing method has high efficiency. The staggered connection enhances the integrity of the structure. The bowl-shaped structure optimizes the stress, reduces the bending moment and shear force of the sealing layer 3, and reduces costs. The bottom sealing concrete 200 is poured first and then the drainage construction is carried out, which ensures safety and reduces the impact on the surrounding environment.

[0085] It is worth noting that the height of the poured bottom seal concrete 200 is consistent with the height of the blade foot ring 21, and the bottom surface of the circular bottom seal member 33 can abut against the bottom seal concrete 200. According to theoretical mechanics, under uniform external pressure, the reasonable arch axis of the bowl-shaped structure can make the cross section only subject to axial compression, and the bending moment and shear force are zero. Under the action of approximately uniform external pressure, the internal force on the cross section of the bottom seal layer 3 of the bowl-shaped structure of the prefabricated assembled caisson is mainly axial pressure, and the greater the depth of the caisson, the closer the bending moment and shear force are to zero. In view of the characteristics of the bottom seal concrete 200 that is strong in compression and weak in tension, the bottom seal layer 3 of the bowl-shaped structure is almost in a pure compression state, giving full play to the compressive performance of the bottom seal concrete 200, greatly reducing the thickness and reinforcement amount of the bottom seal layer 3, and reducing investment costs. At the same time, because the bottom seal concrete 200 is basically in a compressive state, it effectively suppresses the expansion and width of cracks, and improves the durability and stability of the structure.

[0086] In addition, during the excavation of the internal soil and the sinking of the shaft 2, there is no need to adopt drainage measures, and completely undrained sinking can be achieved. On the one hand, the disturbance of the surrounding water and soil environment by drainage is avoided, and the problems of ground settlement and soil displacement caused by groundwater loss are effectively prevented, the impact on surrounding buildings and underground pipelines is reduced, and the ecological environment is protected. On the other hand, the balance of water pressure inside and outside the shaft 2 in the undrained sinking state can reduce the risk of soil collapse and improve the stability of the sinking process. At the same time, the installation and maintenance costs of precipitation equipment are saved, the construction process is simplified, and the construction period is shortened. In addition, this method can also avoid the loss of sand and soil caused by drainage, ensure the interaction balance between the prefabricated assembled caisson and the surrounding soil, and enhance construction safety and environmental friendliness.

[0087] like Figure 1As shown, the locking ring 24 is provided with ribs 241 along its circumference. The locking ring beam 1 is provided with a tongue-and-groove 11. Ribs 241 engage with the tongue-and-groove 11 to provide an anti-floating reaction force. This engagement effectively resists the upward force of the caisson, ensuring the stability of the caisson structure. Furthermore, this plug-and-go connection facilitates assembly, improving construction efficiency while enhancing the reliability of the connection between the locking ring 24 and the locking ring beam 1, ensuring the overall structural safety of the caisson.

[0088] like Figure 1 As shown, anti-floating piles 8 are provided at the lower end of the locking ring beam 1. The anti-floating piles 8 can provide a reaction force for the anti-floating of the wellbore 2, effectively resist the upward effect of the buoyancy of groundwater on the wellbore 2, ensure the stability of the wellbore 2 during the construction and use stages, enhance the overall anti-floating ability of the prefabricated assembled caisson, reduce the risk of floating, and ensure the normal function of the caisson.

[0089] Furthermore, the anti-floating piles 8 can also serve as compression piles, forming the pile foundation for caisson construction machinery. In this case, the interlocking ring beam 1 can serve as both a pile foundation cap and a construction platform. This reduces the cost and workload of separately setting up pile foundations for construction machinery, improving the utilization efficiency of the anti-floating piles 8. Furthermore, the interlocking ring beam 1 serves as both a cap and a platform, simplifying the construction process and providing a stable support surface for caisson construction machinery. This ensures ease and cost-effectiveness of construction operations, and optimizes the practicality of the overall caisson structure.

[0090] like Figure 1 As shown, the inner ring of the blade foot ring 21 is provided with a second groove 211, which can be engaged with the bottom seal concrete 200. The engagement of the second groove 211 with the bottom seal concrete 200 can improve the connection reliability between the blade foot ring 21 and the bottom seal concrete 200, enhance the integrity of the caisson bottom, optimize the load-bearing performance, ensure the stability of the bottom seal layer 3, and facilitate construction, thereby improving the pouring quality of the bottom seal concrete 200.

[0091] like Figure 1-Figure 3 As shown, grouting holes 301 are provided on the first sector-shaped connecting portion 311; grouting holes 301 are provided on the second sector-shaped connecting portion 321; and grouting holes 301 are provided on the circular bottom seal 33 for grouting. Grouting holes 301 facilitate the injection of filling material 300, eliminating assembly gaps, enhancing the integrity and sealing of the bottom seal layer 3, and preventing groundwater leakage. Grouting also optimizes structural stress, improves the stability of the bowl-shaped bottom seal layer 3, and ensures tight connections between the prefabricated and assembled caisson components, improving construction quality.

[0092] In this embodiment, filler material 300 is injected into the cavity enclosed by the bottom seal layer 3, the bottom seal concrete 200, and the blade foot ring 21. This filler material 300 improves the integrity of the prefabricated caisson's bottom and optimizes its mechanical properties. It also effectively prevents groundwater seepage, enhances the sealing properties of the bottom seal layer 3, and ensures the stability and safety of the prefabricated caisson.

[0093] Optionally, depending on the size of the reserved grouting hole 301, the filling material 300 selected for injection can be grouting cement mortar or fine stone concrete. Suitable materials can be selected according to the actual project conditions to ensure the filling effect. No specific limitation is made here.

[0094] In other embodiments, the grouting holes 301 may be arranged on only one of the first sector-shaped connecting portion 311, the second sector-shaped connecting portion 321, or the circular bottom sealing member 33, depending on actual project requirements; or on any two of the first sector-shaped connecting portion 311, the second sector-shaped connecting portion 321, and the circular bottom sealing member 33. The specific arrangement method needs to be determined in combination with factors such as the assembly accuracy of the bottom sealing layer 3, the anti-seepage requirements, and the construction process, and is not a sole limitation here.

[0095] In summary, in this embodiment, after performing the above-mentioned caisson bottom sealing method, the following steps may also be performed:

[0096] (1) Grouting is performed through the grouting holes 301 reserved on the bottom sealing layer 3;

[0097] (2) After the grouting is completed, the bottom concrete 400 is used to lay the bottom and level the top of the bottom sealing layer 3 of the bowl-shaped structure to form the shield starting and receiving construction operation surface.

[0098] On the one hand, grouting through the grouting holes 301 of the bottom seal layer 3 fills structural gaps, enhancing the bottom seal's density and waterproofing. On the other hand, after grouting, the bottom concrete 400 is laid and leveled on the bottom seal layer 3 to form a smooth shield starting and receiving construction operation surface. This not only ensures the safe and stable progress of shield construction, but also further enhances the integrity and load-bearing capacity of the prefabricated caisson bottom structure, ensuring construction quality and efficiency.

[0099] like Figure 4 As shown, the prefabricated assembled caisson also includes a first oblique bolt 41. A first groove 221 is provided on the connecting ring 22. The outer ring edge of the first fan-shaped connecting portion 311 is plugged into the first groove 221, and the first fan-shaped connecting portion 311 is connected to the connecting ring 22 via the first oblique bolt 41. The plug-in fit and the oblique bolt connection form a double fixation, enhancing the connection reliability and improving the coordinated force-bearing capacity of the sealing layer 3 and the wellbore 2. In addition, the design of the first oblique bolt 41 is easy to assemble, which can improve construction efficiency, while enhancing the sealing of the joints, preventing groundwater leakage, and ensuring the safety of the overall structure of the caisson.

[0100] like Figure 4 As shown, in this embodiment, the first oblique bolt 41 is sequentially passed through the first fan-shaped connecting portion 311 and the connecting ring 22, and a sealing ring 72 and a washer 73 are provided at the contact point between the nut of the first oblique bolt 41 and the first fan-shaped connecting portion 311. The end of the first oblique bolt 41 is inserted into the connecting ring 22, and an oblique bolt sleeve 75 is sleeved on the end of the first oblique bolt 41. A rubber plate 74 is clamped at the plug-in fitting place between the outer ring edge of the first fan-shaped connecting portion 311 and the first groove 221, and a sealant 71 is provided at one end of the plug-in fitting place to seal the connection between the outer ring edge of the first fan-shaped connecting portion 311 and the first groove 221, and a sealing gasket 76 is provided at the other end to seal the connection between the outer ring edge of the first fan-shaped connecting portion 311 and the first groove 221. The multiple sealing structures effectively prevent groundwater leakage and enhance the sealing of joints. The sealant 71, sealing ring 72, rubber sheet 74, and sealing gasket 76 improve the reliability of connection and sealing. The gasket 73 is evenly stressed. The inclined bolt sleeve 75 protects the first inclined bolt 41, ensuring the waterproofness and safety of the prefabricated assembled caisson.

[0101] like Figure 2 and Figure 5 As shown, in this embodiment, the prefabricated assembled caisson further includes a second oblique bolt 42. Any two first fan-shaped connecting portions 311 are connected by the second oblique bolt 42, any two second fan-shaped connecting portions 321 are connected by the second oblique bolt 42, the first fan-shaped connecting portion 311 and the second fan-shaped connecting portion 321 are connected by the second oblique bolt 42, and the second fan-shaped connecting portion 321 and the circular bottom sealing member 33 are connected by the second oblique bolt 42. The connection through the second oblique bolt 42 facilitates the assembly of the various components, enhances the integrity and connection reliability of the bottom sealing layer 3, improves the shear resistance and anti-floating capability, and facilitates construction operations, ensuring the stability and safety of the bottom sealing layer 3 of the bowl-shaped structure.

[0102] like Figure 3 and Figure 6 As shown, in other embodiments, the prefabricated assembled caisson further includes a first bent bolt 51, any two first fan-shaped connecting parts 311 are connected by the first bent bolt 51, any two second fan-shaped connecting parts 321 are connected by the first bent bolt 51, the first fan-shaped connecting part 311 and the second fan-shaped connecting part 321 are connected by the first bent bolt 51, and the second fan-shaped connecting part 321 and the circular bottom sealing member 33 are connected by the first bent bolt 51. The connection through the first bent bolt 51 can adapt to the assembly angle, enhance the connection tightness and integrity between the various components of the bottom sealing layer 3, improve the deformation resistance of the structure, facilitate on-site assembly, and ensure the stability and safety of the bottom sealing layer 3 of the bowl-shaped structure under groundwater pressure.

[0103] It is worth noting that the internal force of the bottom sealing layer 3 of the bowl-shaped structure is mainly axial pressure, and the bending moment and shear force are very small. After the bottom sealing layer 3 is split into prefabricated parts and assembled, the prefabricated parts are the first fan-shaped connecting part 311, the second fan-shaped connecting part 321 and the circular bottom sealing part 33. The axial pressure at the joints of the prefabricated parts is still borne by the bottom sealing concrete 200, and the bending moment and shear force are borne by the bolts, that is, the second inclined bolts 42 or the first bent bolts 51, which can meet the bearing capacity requirements, and each prefabricated part is compressed and self-locked under the action of the bolts tightening and external pressure to achieve a stable pressure-bearing function.

[0104] like Figure 5-Figure 6 As shown, a sealing and waterproof structure is provided at the junction of any two first fan-shaped connecting portions 311, the junction of any two second fan-shaped connecting portions 321, the junction between the first fan-shaped connecting portion 311 and the second fan-shaped connecting portion 321, and the junction between the second fan-shaped connecting portion 321 and the circular bottom sealing member 33. This sealing and waterproof structure enhances the impermeability of the bottom sealing layer 3, preventing groundwater leakage through the joints and improving the overall waterproofness of the caisson. It also prevents erosion of the joints by water and soil pressure, ensures the reliability of the connections between the components, and enhances the stability and durability of the bowl-shaped bottom sealing layer 3.

[0105] In this embodiment, for the convenience of description, the connection between any two first fan-shaped connection parts 311, the connection between any two second fan-shaped connection parts 321, the connection between the first fan-shaped connection part 311 and the second fan-shaped connection part 321, and the connection between the second fan-shaped connection part 321 and the circular bottom cover 33 are defined as partial seams 302, and each partial seam 302 is provided with a sealing and waterproof structure.

[0106] like Figure 5 As shown, in this embodiment, taking the case where any two first fan-shaped connecting parts 311 are connected by the second oblique bolt 42 as an example, the second oblique bolt 42 is sequentially passed through the two first fan-shaped connecting parts 311, and a sealing ring 72 and a washer 73 are provided at the contact point between the nut of the second oblique bolt 42 and one of the first fan-shaped connecting parts 311. The end of the second oblique bolt 42 is inserted into the other first fan-shaped connecting part 311, and an oblique bolt sleeve 75 is sleeved on the end of the second oblique bolt 42. A rubber sheet 74 is sandwiched between the subdivision seams 302 of the two first fan-shaped connecting parts 311, and one end of the subdivision seam 302 is sealed by a sealant 71, and the other end is sealed by a sealing gasket 76. The multiple sealing structure effectively prevents groundwater leakage and enhances the sealing performance of the joint. The sealant 71, sealing ring 72, rubber sheet 74, and sealing gasket 76 improve the connection and sealing reliability. The gasket 73 is evenly stressed. The oblique bolt sleeve 75 protects the first oblique bolt 41, ensuring the waterproofness and safety of the bottom sealing layer 3. The sealing and waterproof structures provided in other branch seams 302 are consistent with the above structures and will not be described in detail here.

[0107] like Figure 6As shown, in other embodiments, taking the case where any two first fan-shaped connecting parts 311 are connected by the first bent bolt 51 as an example, two first fan-shaped connecting parts 311 are respectively passed through the two ends of the first bent bolt 51, and nuts are provided at both ends of the first bent bolt 51. The two nuts are provided with sealing rings 72 and washers 73 at the abutment points with the corresponding first fan-shaped connecting parts 311. The subdivision seams 302 of the two first fan-shaped connecting parts 311 are sandwiched with rubber plates 74, and one end of the subdivision seam 302 is sealed by sealant 71, and the other end is sealed with a sealing gasket 76. The fixing of the two ends of the first bent bolt 51 enhances the firmness of the connection, and the multiple sealing structures effectively prevent groundwater leakage. The sealing ring 72 and the rubber plate 74 improve the sealing of the joint, the sealant 71 and the sealing gasket 76 form a double waterproof barrier, and the gasket 73 is evenly stressed to ensure the waterproofness and connection reliability of the sealing bottom layer 3. The sealing and waterproof structures provided in the other subdivision seams 302 are consistent with the above structure and will not be described in detail here.

[0108] like Figure 7-Figure 8 As shown, the blade ring 21, connecting ring 22, multiple standard rings 23, and locking ring 24 are all annular structures. Each annular structure is formed by multiple segments 201 connected along the annular direction. The multiple segments 201 in the same annular structure are connected using staggered joints. The staggered joints enhance the integrity and deformation resistance of the annular structure, avoid stress concentration, improve the rigidity and stability of the annular structure, effectively resist water and soil pressure, and optimize force distribution, ensuring safety and reliability during caisson construction and operation.

[0109] like Figure 9 As shown, in this embodiment, the prefabricated caisson further includes third oblique bolts 43, connecting any two circumferentially adjacent segments 201 via the third oblique bolts 43. The third oblique bolts 43 enhance the connection reliability between the segments 201, improve the integrity of the annular structure, and effectively resist annular water and soil pressure. This connection method facilitates on-site assembly, improves construction efficiency, and reduces joint deformation, lowering the risk of groundwater leakage, thereby ensuring the stability and safety of the caisson structure.

[0110] like Figure 10 As shown, in other embodiments, the prefabricated caisson further includes a second bent bolt 52, and any two circumferentially adjacent segments 201 are connected by the second bent bolt 52. The second bent bolt 52 can adapt to the splicing angle of the segments 201, making the connection more stable, effectively enhancing the integrity of the annular structure, improving shear and deformation resistance, reducing the risk of joint leakage, and facilitating construction operations, speeding up assembly, and ensuring the structural safety and performance of the caisson under complex working conditions.

[0111] like Figure 11As shown, the prefabricated caisson also includes longitudinal straight bolts 61, connecting two adjacent ring structures. These bolts 61 enhance the longitudinal integrity of the shaft 2, improving its shear and deformation resistance and adapting to varying soil loads. They also facilitate vertical assembly of the ring structures, improving construction efficiency, while minimizing deformation at longitudinal joints and reducing the risk of leakage, thereby ensuring the stability and safety of the overall caisson structure.

[0112] like Figure 11 As shown, the prefabricated caisson also includes a straight bolt sleeve 62 and a shear pin 63. The straight bolt sleeve 62 is sleeved on the outside of the longitudinal straight bolt 61, and the shear pin 63 is sleeved on the outside of the straight bolt sleeve 62 and passes through the longitudinal joints of two adjacent pipe segments 201 to transmit shear force. The longitudinal straight bolts 61, straight bolt sleeves 62 and shear pins 63 work together to enhance the connection strength between adjacent annular structures and improve the overall stability of the caisson. At the same time, the straight bolt sleeve 62 reduces the corrosion risk of the longitudinal straight bolts 61, enhances the shear resistance of the joints, reduces leakage risks, and ensures the safety and reliability of the prefabricated caisson structure.

[0113] like Figure 11 As shown, in this embodiment, for the convenience of description, the connection between two adjacent annular structures in the longitudinal direction is defined as a longitudinal sub-annular seam 202, and each longitudinal sub-annular seam 202 is provided with a sealing and waterproof structure. Two washers 73 are sleeved on the longitudinal straight bolts 61 and arranged at both ends of the shear pin 63, respectively located in the first pipe segment 201 and the second pipe segment 201 adjacent to it in the longitudinal direction. A rubber plate 74 is sandwiched in the middle of the longitudinal sub-annular seam 202, and both ends of the longitudinal sub-annular seam 202 are sealed by sealing gaskets 76. The multiple sealing structure enhances the anti-seepage performance of the longitudinal sub-annular seam 202, prevents the erosion of the joint by water and soil pressure, and improves the sealing and reliability of the wellbore 2 in the longitudinal direction. At the same time, the washers 73 evenly distribute the force on the longitudinal straight bolts 61, and the rubber plates 74 and sealing gaskets 76 work together to ensure the waterproofness and stability of the structure.

[0114] like Figure 12 As shown, the straight bolt sleeve 62 is also provided with a thread 621 and a partition 622. The thread 621 is convenient for threaded connection with the longitudinal straight bolt 61, thereby enhancing assembly convenience and connection reliability; the partition 622 can position the longitudinal straight bolt 61 and separate the internal space of the straight bolt sleeve 62, thereby ensuring the installation accuracy of the shear pin 63, and at the same time improving the structural strength of the straight bolt sleeve 62, thereby ensuring the stress stability and waterproof sealing of the longitudinal annular seam 202 of the wellbore 2.

[0115] like Figure 13As shown, the wall thickness of the shear pin 63 gradually decreases from the middle to the two ends, so that the shear pin 63 can better adapt to the deformation of the longitudinal annular seam 202, reduce stress concentration, and improve shear resistance; at the same time, it is convenient to insert into the joints of adjacent pipe segments 201, improve construction convenience, enhance the reliability of the wellbore 2, and ensure the stability of the prefabricated assembled caisson under water and soil pressure.

[0116] In this embodiment, for the convenience of description, the connection between two circumferentially adjacent segments 201 is defined as a circumferential segment seam 203 , and each circumferential segment seam 203 is provided with a sealing and waterproof structure.

[0117] like Figure 14 As shown, in this embodiment, taking the case where two circumferentially adjacent segments 201 are connected by third oblique bolts 43 as an example, the third oblique bolts 43 are sequentially passed through the two segments 201. A sealing ring 72 and a washer 73 are provided at the abutment between the nut of the third oblique bolt 43 and one of the segments 201. The end of the second oblique bolt 42 is inserted into the other segment 201. An oblique bolt sleeve 75 is sleeved on the end of the third oblique bolt 43. A rubber sheet 74 is sandwiched within the circumferential slit 203 of the two segments 201, and both ends of the circumferential slit 203 are sealed by sealing gaskets 76. The multiple sealing structures effectively block the groundwater leakage path. The third oblique bolt 43 connection enhances the connection reliability between the segments 201. The sealing ring 72 and the rubber sheet 74 improve the sealing of the circumferential slit 203. The sealing gasket 76 forms a waterproof barrier. The gasket 73 is evenly stressed, ensuring the waterproofness and safety of the prefabricated caisson.

[0118] like Figure 15 As shown, in other embodiments, taking the case where two circumferentially adjacent segments 201 are connected by a second bent bolt 52 as an example, the two ends of the second bent bolt 52 are respectively penetrated by the two segments 201, and nuts are provided at both ends of the second bent bolt 52. The two nuts and the corresponding two segments 201 are both provided with sealing rings 72 and washers 73 at the abutment points. A rubber plate 74 is sandwiched in the circumferential segment seam 203 of the two segments 201, and both ends of the circumferential segment seam 203 are sealed by sealing gaskets 76. The second bent bolt 52 enhances the circumferential connection fit, multiple seals block groundwater infiltration, the sealing ring 72 and the rubber plate 74 improve the sealing of the circumferential segment seam 203, the sealing gasket 76 forms a waterproof barrier, and the gasket 73 is evenly stressed, thereby ensuring the waterproofness and safety of the prefabricated caisson.

[0119] In summary, a specific prefabricated caisson can be provided as follows:

[0120] (1) The height of the shaft 2 is 33 meters, the wall thickness is 0.6 meters, the inner diameter is 16 meters, the outer diameter is 17.2 meters, the height of the blade ring 21 is 3 meters, the height of the connecting ring 22 is 3 meters, there are twelve standard rings 23, each standard ring 23 is 2 meters high, and the height of the locking ring 24 is 3 meters. Each annular structure is formed by eight pipe segments 201 connected in the annular direction. Two M36 third oblique bolts 43 or M36 second bent bolts 52 are used to connect each two pipe segments 201 in the annular direction. Sixteen M36 third oblique bolts 43 or M36 second bent bolts 52 are provided on each annular structure. Six M36 longitudinal straight bolts 61 are used to connect each pipe segment 201 in the longitudinal staggered direction. Forty-eight M36 longitudinal straight bolts 61 are provided on each annular structure, which are evenly distributed along the circumference of the annular structure. The angular interval between the center lines of two adjacent M36 longitudinal straight bolts 61 is 7.5 degrees.

[0121] (2) The inner arc radius of the bottom sealing layer 3 of the bowl-shaped structure is 30 meters, the thickness is 0.6 meters, and the outer arc radius is 30.6 meters. The outermost circle is composed of sixteen first fan-shaped connecting parts 311, the block angle of the first fan-shaped connecting parts 311 is 22.5 degrees, and the radial side length is 4 meters; the middle area is composed of eight second fan-shaped connecting parts 321, the block angle is 45 degrees, the radial side length is 3 meters, the staggered angle between the first fan-shaped connecting parts 311 and the second fan-shaped connecting parts 321 is 11.25 degrees, and the central area is a circular bottom sealing part 33 with a radius of 1 meter.

[0122] (3) The first fan-shaped connecting portion 311 and the connecting ring 22 are connected by sixty-four evenly distributed M36 first oblique bolts 41 , and the angular interval between the center lines of two adjacent M36 first oblique bolts 41 is 5.625 degrees.

[0123] (4) The two first fan-shaped connecting parts 311 are connected by four equally spaced M36 second oblique bolts 42 or M36 first bent bolts 51, with a bolt spacing of 1 meter; the first fan-shaped connecting part 311 and the second fan-shaped connecting part 321 are connected by sixteen evenly spaced M36 second oblique bolts 42 or M36 first bent bolts 51, with the angular interval between the center lines of two adjacent bolts being 22.5 degrees.

[0124] (5) The two second fan-shaped connecting parts 321 are connected by three equally spaced M36 second oblique bolts 42 or M36 first bent bolts 51, with a bolt spacing of 1 meter; the second fan-shaped connecting part 321 and the circular bottom cover 33 are connected by eight evenly spaced M36 second oblique bolts 42 or M36 first bent bolts 51, with the angular interval between the center lines of two adjacent bolts being 45 degrees.

[0125] The shaft 2 and the bowl-shaped sealing layer 3 are both prefabricated and assembled in a modular manner. Each annular structure is spliced ​​along the annular direction by the pipe segments 201, and the annular connection is achieved by the third oblique bolts 43 and the second bent bolts 52. The longitudinal straight bolts 61 are used to fix the shaft 2 in a staggered manner to form a stable shaft 2. The sealing layer 3 is staggered and assembled by the first fan-shaped connecting part 311, the second fan-shaped connecting part 321 and the circular bottom sealing part 33. It is connected to the connecting ring 22 by the first oblique bolts 41. The components are reliably connected by the second oblique bolts 42 and the first bent bolts 51. On the one hand, the prefabricated caisson is easy to prefabricate and assemble through a reasonable modular design, which improves construction efficiency while ensuring stability and safety during the construction and use stages. On the other hand, the staggered assembly design enhances the sealing of the joints, reduces the risk of leakage, and effectively resists water and soil pressure. The uniform distribution of the bolts ensures the balanced transfer of loads and improves the shear and deformation resistance of the structure. The specific structures such as the structural form and connection method of other prefabricated caissons are not clearly defined in this embodiment.

[0126] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. A person skilled in the art would be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. Prefabricated caisson, characterized by: include: A locking ring beam (1) is connected to the ground (100); A shaft (2) comprises a cutting edge ring (21), a connecting ring (22), a plurality of standard rings (23) and a locking ring (24) connected in sequence from bottom to top, wherein the cutting edge ring (21) is used for cutting soil and sinking below the ground (100), and the locking ring (24) is connected to the locking ring beam (1); The bottom sealing layer (3) comprises a first annular member (31), a second annular member (32) and a circular bottom sealing member (33) which are sequentially connected from the outside to the inside, wherein the outer ring of the first annular member (31) is connected to the inner ring of the connecting ring (22), and the first annular member (31) is formed by a plurality of first fan-shaped connecting portions (311) sequentially connected along the annular direction; the second annular member (32) is formed by a plurality of second fan-shaped connecting portions (321) sequentially connected along the annular direction, and the first fan-shaped connecting portions (311) and the second fan-shaped connecting portions (321) are connected by staggered seams, so that the bottom sealing layer (3) is constructed into a bowl-shaped structure.

2. The prefabricated caisson according to claim 1, characterized in that: The first fan-shaped connecting portion (311) is provided with a grouting hole (301); and / or the second fan-shaped connecting portion (321) is provided with a grouting hole (301); and / or the circular bottom cover (33) is provided with a grouting hole (301), and the grouting hole (301) is used for grouting.

3. The prefabricated caisson according to claim 1, characterized in that: The prefabricated assembled caisson also includes a first oblique bolt (41), a first groove (221) is provided on the connecting ring (22), the outer ring edge of the first fan-shaped connecting portion (311) is plugged into the first groove (221), and the first fan-shaped connecting portion (311) is connected to the connecting ring (22) through the first oblique bolt (41).

4. The prefabricated caisson according to claim 1, characterized in that: The prefabricated assembled caisson further comprises a second oblique bolt (42), any two of the first fan-shaped connecting parts (311) are connected by the second oblique bolt (42), any two of the second fan-shaped connecting parts (321) are connected by the second oblique bolt (42), the first fan-shaped connecting part (311) and the second fan-shaped connecting part (321) are connected by the second oblique bolt (42), and the second fan-shaped connecting part (321) and the circular bottom cover (33) are connected by the second oblique bolt (42); or; The prefabricated assembled caisson also includes a first bent bolt (51), any two of the first fan-shaped connecting parts (311) are connected by the first bent bolt (51), any two of the second fan-shaped connecting parts (321) are connected by the first bent bolt (51), the first fan-shaped connecting part (311) and the second fan-shaped connecting part (321) are connected by the first bent bolt (51), and the second fan-shaped connecting part (321) and the circular bottom cover (33) are connected by the first bent bolt (51).

5. The prefabricated caisson according to claim 1, characterized in that: The connection between any two of the first fan-shaped connecting parts (311), the connection between any two of the second fan-shaped connecting parts (321), the connection between the first fan-shaped connecting part (311) and the second fan-shaped connecting part (321), and the connection between the second fan-shaped connecting part (321) and the circular bottom cover (33) are all provided with a sealing and waterproof structure.

6. The prefabricated caisson according to any one of claims 1 to 5, characterized in that: The blade foot ring (21), the connecting ring (22), the plurality of standard rings (23) and the locking ring (24) are all annular structures. Each annular structure is formed by connecting a plurality of tube segments (201) along an annular direction, and the plurality of tube segments (201) in the same annular structure are connected by staggered seams.

7. The prefabricated caisson according to claim 6, characterized in that: The prefabricated caisson further comprises longitudinal straight bolts (61), and two adjacent annular structures are connected by the longitudinal straight bolts (61).

8. The prefabricated caisson according to claim 7, characterized in that: The prefabricated assembled caisson also includes a straight bolt sleeve (62) and a shear pin (63), wherein the straight bolt sleeve (62) is sleeved on the outside of the longitudinal straight bolt (61), and the shear pin (63) is sleeved on the outside of the straight bolt sleeve (62) and passes through the longitudinal joints of two adjacent pipe segments (201) for transmitting shear force.

9. A method for assembling a caisson shaft, characterized in that: Applicable to the prefabricated caisson according to any one of claims 1 to 8, the caisson shaft assembly method comprises: S1: the blade foot ring (21) cuts the soil and digs out the soil surrounded by the blade foot ring (21), so that the blade foot ring (21) sinks below the ground (100); S2: The connecting ring (22) is connected to the blade foot ring (21), and the soil surrounded by the connecting ring (22) and the blade foot ring (21) is excavated to allow the connecting ring (22) to sink below the ground (100); S3: The standard ring (23) is connected to the connecting ring (22), and the soil surrounded by the standard ring (23), the connecting ring (22) and the blade foot ring (21) is excavated. A plurality of standard rings (23) are connected one by one, and the stacking and sinking are repeated until the last standard ring (23) sinks below the ground (100); S4: placing the locking ring (24) in the locking ring beam (1) and connecting it to the locking ring beam (1), and connecting the locking ring (24) to the last standard ring (23).

10. A method for sealing the bottom of a caisson, characterized in that: Applied to the prefabricated caisson according to any one of claims 1 to 8, the caisson bottom sealing method comprises: S1: pouring bottom seal concrete (200) in the wellbore (2), pumping out water in the wellbore (2) after the bottom seal concrete (200) reaches a preset strength, connecting a plurality of first fan-shaped connecting parts (311) one by one to the inner ring of the connecting ring (22), and connecting the plurality of first fan-shaped connecting parts (311) in sequence along the annular direction to form the first annular member (31); S2: the second fan-shaped connecting parts (321) are staggeredly connected to the first fan-shaped connecting parts (311) one by one, and a plurality of the second fan-shaped connecting parts (321) are sequentially connected along the annular direction to form the second annular member (32); S3: The plurality of second fan-shaped connecting portions (321) are all connected to the circular bottom cover (33), and the bottom cover (3) is constructed into a bowl-shaped structure.

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