LU501867B1

LU501867B1 - Method for rapidly constructing a large passageway underwater through shallow burial and cut-and-cover with no dry dock

Info

Publication number: LU501867B1
Application number: LU501867A
Authority: LU
Inventors: Weiguo He; Qingfang Liu; Huagui Zhou; Wei Cao; Manli Fei; Guogang Fan
Original assignee: China Railway Liuyuan Group Co Ltd; China Railway Tunnuel Survey Design Inst Co Ltd
Priority date: 2021-04-25
Filing date: 2022-04-20
Publication date: 2022-10-25
Also published as: CN112982476A; CN112982476B

Abstract

Provided is a method for rapidly constructing a large passageway underwater through shallow burial and cut-and-cover with no dry dock. A basic structural unit (1) used in the method has features described below. A seal door (12) is disposed at one end of the basic structural unit (1) and an opening is disposed on the other end of the basic structural unit (1). A drainage pressure relief valve (13) is disposed at a lower end of the seal door (12). A rubber waterstop (14) is disposed around an end portion of the basic structural unit (1). A floating and ballast tank (11) capable of adjusting an inflow capacity and an outflow capacity is fixed in the basic structural unit (1). At least four axis positioning support bases (15) are disposed on the bottom of the basic structural unit (1).

Description

METHOD FOR RAPIDLY CONSTRUCTING A LARGE PASSAGEWAY LU501867 UNDERWATER THROUGH SHALLOW BURIAL AND CUT-AND-COVER WITH NO

DRY DOCK TECHNICAL FIELD

[0001] The present invention relates to the field of underwater engineering and, in particular, to a method for rapidly constructing a large passageway underwater through shallow burial and cut-and-cover with no dry dock and a basic structural unit of the large passageway.

BACKGROUND

[0002] Most cities with a population of over one million in China are built by rivers, lakes, and seas. The rivers, lakes, or seas not only bring development to a city but also divide the city with two banks, thereby to a certain extent hindering the formation of the overall traffic network of the city on the two banks. A tunnel has outstanding advantages, for example, the tunnel is all-weather and has no influence on shipping. Constructing an underwater tunnel is an important means for the city on the two banks to break through barriers between the rivers, lakes, or seas, connect an urban road network, and develop a regional economy.

[0003] Conventional methods for constructing underwater passageways include a mining method, a shield method, and an immersed tube method. Tunnels constructed through different construction methods require different burial depths. With the same longitudinal gradient, the greater burial depth a tunnel has, the longer wires connected to two banks, the larger area, and the higher requirements for wire connection the tunnel has, and the more clearly urban land is divided. On the other hand, due to the influence of water, geological conditions under rivers, lakes, and seas are generally poor, and soft soil is thick. However, a tunnel constructed through the mining method needs to be buried in a rock stratum and has requirements for the thickness of an upper rock overburden. A tunnel constructed through the shield method may be buried in soft soil. However, the burial depth of the tunnel is required to be equal to or greater than the diameter of the tunnel. A tunnel constructed through the immersed tube method has the shallowest burial depth which merely needs to meet anti-floating requirements of the tunnel. To sum up, in the three construction methods, the area of the underwater tunnel constructed through the mining method is larger than the area of the underwater tunnel constructed through the shield method. The area of the underwater tunnel constructed through the shield method is larger than the area of the underwater tunnel constructed through the immersed tube method. 1

[0004] In order to save land, the immersed tube method is a relatively ideal construction LUS01867 method for an underwater passageway. However, current construction methods and engineering experience of 20 underwater passageways constructed or being constructed through the immersed tube method in mainland China are summarized, and problems and deficiencies described below are found.

[0005] (1) When tunnel elements are manufactured, it is necessary to construct a large-area temporary dry dock near immersion waters in advance as a site for prefabricating tunnel sections. However, in general, since there are dense buildings and precious land resources on the two banks of a city, it is relatively difficult to find a large-area temporary site near the immersion waters as the dry dock. Moreover, the temporary dry dock needs to be backfilled after the completion of an immersed tube tunnel, resulting in a large overall work quantity, a long construction period, and high temporary project costs.

[0006] (2) Generally, a basic structural unit has a length of 100m to 120m and a weight of 40,000 tons to 50,000 tons, thereby making it difficult to transfer a tunnel element from the dry dock to waters. Water has to be flooded into the dry dock to float a tunnel section. Then, 4 to 6 towboats haul the tunnel element to complete the transference of the tunnel element before immersion.

[0007] (3) The tunnel element has a sealed cavity and floats through buoyancy of the tunnel element. During the transportation of the tunnel element through floating, a top plate is always about 10cm above a water surface. The tunnel element easily sways and surges under the combined action of forces in different directions and angles such as a water flow impact force, a wave force, and tractive forces of towboats, resulting in the overturning of the tunnel element and causing accidents. In addition, when the tunnel element is immersed, it is necessary to provide dedicated immersion ships for performing immersion, resulting in a great construction difficulty, a long period, and high costs.

[0008] (4) When the tunnel element is compressed and connected underwater, a level is controlled by one fulcrum at a joint and two fulcrums at a tail. The fulcrums are few so that a long tunnel element easily tends to turn around under the action of a water flow force, thereby making it difficult to control an axis deviation and a vertical level precisely. 2

SUMMARY LU501867

[0009] The present invention provides a method for rapidly constructing a large passageway underwater through shallow burial and cut-and-cover, and basic structural units of a passageway used in conjunction with the method, so that it is unnecessary to construct a large temporary dry dock for manufacturing the basic structural units, flood water into a dry dock to transport the basic structural units through floating, and provide dedicated immersion ships for transporting the basic structural units through floating and immersing the basic structural units.

[0010] The present invention adopts following technical solutions. A basic structural unit of a large passageway constructed underwater through shallow burial and cut-and-cover with no dry dock is provided. Each of the plurality of basic structural units is formed by integrally casting a top plate, a bottom plate, and two sidewalls. A seal door is disposed at one end of the basic structural unit and an opening is disposed on the other end of the basic structural unit. A drainage pressure relief valve is disposed at a lower end of the seal door. A rubber waterstop is disposed around an end portion of the basic structural unit at the side of the seal door. A floating and ballast tank is fixed in the basic structural unit. At least four axis positioning support bases are disposed on the bottom of the basic structural unit.

[0011] In the preceding solution, the basic structural unit has a longitudinal length of 22m to 25m and a weight less than or equal to 6,000 tons.

[0012] In the preceding solution, the number of the axis positioning support bases is four, and each two of the four axis positioning support bases are arranged in parallel. Each of the axis positioning support bases has a length of 0.6m, a width of 0.4m, and a height of 0.5m.

[0013] In the preceding solution, an axial hauling locker or a fixing block configured to be matched with the axial hauling locker is disposed on the top plate of the basic structural unit.

[0014] The present invention further provides a method for rapidly constructing a large passageway underwater through shallow burial and cut-and-cover with no dry dock. Specifically, the method includes the following steps.

[0015] In step S1, first to N-th basic structural units described in the preceding solution are directly prefabricated on a flat ground near the embankment line of passageway waters. 3

[0016] In step S2, a cast-in-place structural unit is constructed through a cut-and-cover LUS01867 method with a cofferdam below the embankment line of the passageway waters, where the cast-in-place structural unit is configured to be connected to the first basic structural unit prefabricated in step S1. À seal door is disposed at a connection end of the cast-in-place structural unit. A drainage pressure relief valve is disposed at a lower end of the seal door. An axial hauling locker or a fixing block configured to be matched with the axial hauling locker is disposed on the top plate of the cast-in-place structural unit.

[0017] In step S3, an underwater foundation pit is excavated under the waters where a passageway is located. A jack for adjusting gradients is installed in the underwater foundation pit. A longitudinal-slope positioning steel plate is fixedly connected onto the jack for adjusting gradients so as to position a longitudinal slope of the passageway. The longitudinal-slope positioning steel plate is provided with axis positioning holes. The number and positions of the axis positioning holes correspond to the number and positions of the axis positioning support bases on the bottom of the basic structural unit. The longitudinal-slope positioning steel plate is disposed so that a level of the bottom of the passageway can be effectively controlled. Multiple axis positioning holes are provided on the longitudinal-slope positioning steel plate along the longitudinal direction of the passageway so that the horizontal position of the passageway can be effectively controlled.

[0018] In step S4, a slide is constructed at the waters embankment of the place where the basic structural units of the passageway are prefabricated. The top of the slide is flush with the embankment line, and the bottom of the slide extends below the surface of waters.

[0019] In step S5, the prefabricated first basic structural unit is transferred from the land to the waters by using the slide. The volume of air in the floating and ballast tank in the basic structural unit is adjusted to balance the self-weight of the basic structural unit so that the basic structural unit is kept in a floating state in immersion waters. A floating crane pulls the basic structural unit to an immersion position. The basic structural unit is completely suspended and submerged in water during the whole pulling process.

[0020] In step S6, the first basic structural unit is immersed on the longitudinal-slope positioning steel plate. The axis positioning support bases on the bottom of the first basic structural unit are completely embedded in the axis positioning holes on the longitudinal-slope positioning steel plate. The first basic structural unit is positioned precisely in the horizontal 4 direction and the longitudinal direction. LU501867

[0021] In step S7, underwater compression and connection are performed. The axial hauling locker and the fixing block, which are disposed on the top plate of the first basic structural unit and the top plate of the cast-in-place structural unit at a joint respectively, are pulled to be connected so as to implement the preliminary compression and connection of rubber waterstops at the first joint. The drainage pressure relief valve at the lower end of the seal door of the cast-in-place structural unit is opened. A pressure in a cavity enclosed by the rubber waterstop becomes lower. The seal door of the first basic structural unit compresses the joint under an external water pressure, and the rubber waterstop is compressed for the second time to prevent the passage of water.

[0022] In step S8, the step S6 and the step S7 are repeated to sequentially complete underwater compression and connection between a second basic structural unit and the first basic structural unit, underwater compression and connection between a third basic structural unit and the second basic structural unit,..., and underwater compression and connection between the N-th basic structural unit and an (N-1)-th basic structural unit to complete the whole construction of an underwater passageway.

[0023] Further, in the preceding construction method, an axis positioning hole has the width of 0.405m perpendicular to the axis direction of the passageway and the length of 1.5m parallel to the axis direction of the passageway so as to provide a compression distance required by the rubber waterstop at the joint for preventing the passage of water.

[0024] Compared with the related art, the present invention has advantages and effects described below.

[0025] 1. In the method for rapidly constructing a large passageway underwater through shallow burial and cut-and-cover with no dry dock according to the present invention, the basic structural unit has a length of 22 m to 25 m and a weight which does not exceed 6,000 tons. When the basic structural unit is manufactured, it is unnecessary to construct a large temporary dry dock near the waters as a prefabrication site. It is merely necessary to select a site on the flat ground near the embankment of the immersion waters. In addition, no foundation pit needs to be excavated at the site. It is unnecessary to flood water for transporting the basic structural unit through floating and repair and maintain the site later. Thus, the difficulty in selecting a site for prefabricating the basic structural unit is reduced, and impacts on the environment and social 5 cultures near the immersion waters are avoided. On the other hand, tunnel elements are LU501867 prefabricated with no dry dock so that investments in temporary projects can be reduced, overall project costs of the underwater passageway can be saved, and a construction period of the underwater passageway can be shortened.

[0026] 2. In the method for rapidly constructing a large passageway underwater through shallow burial and cut-and-cover with no dry dock according to the present invention, the seal door is disposed at one end of the basic structural unit and the opening is disposed on the other end of the basic structural unit. The floating and ballast tank is disposed inside the basic structural unit. During transportation from the land to the waters and immersion, no dedicated immersion device is needed. The volume of air in the floating and ballast tank is adjusted to balance the self-weight of a structure so that the basic structural unit is kept in the floating state in water. Thus, in the case where it is unnecessary to provide a relatively great additional pulling force to control vertical balance, one floating crane is needed in the waters to efficiently transport the basic structural unit through floating and precisely immerse the basic structural unit. Compared with an existing basic structural unit having two sealed ends and an internal cavity and floating by buoyancy of the existing basic structural unit, on the one hand, less special equipment is used, difficulty of over-water construction is greatly reduced, and the manpower, materials, and financial resources needed for transporting the tunnel element through floating and immersing the tunnel element are reduced. On the other hand, during the transportation of the basic structural unit through floating, the basic structural unit is prevented from swaying and surging under the combined action of forces in different directions and angles such as a water flow impact force, a wave force, and the tractive force of a towboat and resulting in risks of overturning or causing accidents.

[0027] 3. In the method for rapidly constructing a large passageway underwater through shallow burial and cut-and-cover with no dry dock according to the present invention, the axis positioning support bases are disposed on the bottom of the basic structural unit, and the longitudinal-slope positioning steel plate is disposed on the foundation pits in the waters to position the longitudinal-slope of the passageway. During immersion, the axis positioning support bases disposed on the bottom of structural units are completely embedded in the axis positioning holes disposed on the longitudinal-slope positioning steel plate to precisely position the basic structural units. Thus, it is effectively ensured that no axis deviation exists when the basic structural unit is immersed, thereby providing a guarantee for precise underwater compression and connection between different structural units.

6

BRIEF DESCRIPTION OF DRAWINGS LU501867

[0028] To illustrate the technical solutions in embodiments of the present invention or the technical solutions in the related art more clearly, drawings used in the description of the embodiments or the related art will be briefly described below. Apparently, the drawings described below illustrate merely part of the embodiments of the present invention, and those of ordinary skill in the art may obtain other drawings based on the drawings described below without any creative work.

[0029] FIG.1 is a plan view showing an arrangement of immersion waters, a slide, and a prefabrication site of a basic structural unit according to an embodiment of the present invention:

[0030] FIG. 2 is a structure view of a basic structural unit according to an embodiment of the present invention;

[0031] FIG. 3 is a schematic view showing a process of transferring a basic structural unit from the land to waters in a method for rapidly constructing a large passageway underwater through shallow burial and cut-and-cover with no dry dock according to an embodiment of the present invention; and

[0032] FIG. 4 is a schematic view showing a process of compressing and connecting a basic structural unit underwater in a method for rapidly constructing a large passageway underwater through shallow burial and cut-and-cover with no dry dock according to an embodiment of the present invention.

[0033] Reference list 1 basic structural unit 2 embankment line 3 slide 4 passageway waters 6 floating crane 7 cast-in-place structural unit 8 jack for adjusting gradients 9 longitudinal-slope positioning steel plate 7

91 axis positioning hole LU501867 10 gaps of foundation trenches 11 floating and ballast tank 12 seal door 13 drainage pressure relief valve 14 rubber waterstop 15 axis positioning support base 16 fixing block 17 axial hauling locker

DETAILED DESCRIPTION

[0034] The present invention is further described below in detail in conjunction with embodiments. The embodiments described below are for the explanation of the present invention. However, the present invention is not limited to the embodiments described below.

[0035] Embodiment one: as shown in FIG. 2, a basic structural unit of a large passageway constructed underwater through shallow burial and cut-and-cover with no dry dock is provided. Each of the plurality of basic structural units 1 is formed by integrally casting a top plate, a bottom plate, and two sidewalls. A seal door 12 is disposed at one end of the basic structural unit and an opening is disposed on the other end of the basic structural unit. A drainage pressure relief valve 13 is disposed at a lower end of the seal door 12. A rubber waterstop 14 is disposed around an end portion of the basic structural unit at the side of the seal door 12. A floating and ballast tank 11 capable of adjusting an inflow capacity and an outflow capacity is disposed in the basic structural unit 1. At least four axis positioning support bases 15 are disposed on the bottom of the basic structural unit 1. An axial hauling locker 17 or a fixing block 16 configured to be matched with the axial hauling locker 17 is disposed on the top plate of the basic structural unit 1.

[0036] In embodiment one, the basic structural unit 1 has a longitudinal length limited to 22m to 25m and a weight less than or equal to 6,000 tons. The number of the axis positioning support bases 15 is four, and each two of the four axis positioning support bases 15 are arranged in parallel. Each of the axis positioning support bases 15 has a length of 0.6m, a width of 0.4m, and a height of 0.5m. 8

[0037] The basic structural unit described in embodiment one has a closed head end and an | LU501867 open tail end. The rubber waterstop 14 is disposed at the end surface of the head end and can prevent the passage of water after being compressed. The drainage pressure relief valve 13 is reserved. The open tail end can allow river water to come into a structural unit.

[0038] Further, the basic structural unit described in embodiment one may be prefabricated on a flat ground and slides from the land to waters through a slide to be immersed into water. The volume of air in the floating and ballast tank is adjusted to balance the self-weight of a structure so that the basic structural unit is kept in a floating state in the waters. During the whole process, it is unnecessary to provide an additional pulling force to control vertical balance, and the basic structural unit is pulled by one floating crane in the waters and is transported in an immersed state to an immersion position.

[0039] The basic structural unit described in embodiment one is applicable to the construction of a large underwater passageway constructed underwater through shallow burial, cut-and-cover, and the immersed tube method. The internal structure, the longitudinal length, and the tonnage of the basic structural unit are configured reasonably. A site of a small area is needed for prefabricating the basic structural unit. The site can be selected on a flat ground near the embankment line of immersion waters. The basic structural unit has high applicability and high construction efficiency.

[0040] Embodiment two: as shown in FIGS. 1 to 4, a method for rapidly constructing a large passageway underwater through shallow burial and cut-and-cover with no dry dock is provided, where the basic structural unit described in embodiment one is used for constructing the large passageway. Specifically, the method includes steps described below.

[0041] In step S1, as shown in FIG. 1, first to N-th basic structural units 1 described in embodiment one are directly prefabricated on a flat ground near the embankment line 2 of passageway waters 4. The structure view of the basic structural unit 1 is shown in FIG. 2.

[0042] In step S2, as shown in FIG. 4, a cast-in-place structural unit 7 is constructed through a cut-and-cover method with a cofferdam below the embankment line 2 of the passageway waters 4, where the cast-in-place structural unit 7 is configured to be connected to the first basic structural unit prefabricated in step S1. A seal door 12 is disposed at a connection end of the cast-in-place structural unit 7. A drainage pressure relief valve 13 is disposed at a lower end of the seal door 12. An end portion of the cast-in-place structural unit 7 on the side of the seal door 9

12 is flat and smooth so that a rubber waterstop at the connection end is easily compressed for ~~ LU501867 preventing the passage of water. An axial hauling locker 17 or a fixing block 16 configured to be matched with the axial hauling locker 17 is disposed on the top plate of the cast-in-place structural unit 7.

[0043] In step S3, an underwater foundation pit is excavated under the waters where a passageway is located. A jack 8 for adjusting gradients is installed in the underwater foundation pit. A longitudinal-slope positioning steel plate 9 is fixedly connected onto the jack 8 for adjusting gradients so as to position a longitudinal slope of the passageway. The longitudinal-slope positioning steel plate 9 is provided with axis positioning holes 91. The number and positions of the axis positioning holes 91 correspond to the number and positions of the axis positioning support bases 15 on the bottom of the basic structural unit. The longitudinal-slope positioning steel plate 9 and the axis positioning holes 91 are disposed for ensuring that four axis positioning support bases 15 of the basic structural unit are completely inserted so as to implement precise positioning with no axis deviation.

[0044] In step S4, as shown in FIG. 3, a slide 3 is constructed at the waters embankment of the place where the basic structural units of the passageway are prefabricated. The top of the slide 3 is flush with the embankment line 2, and the bottom of the slide 3 extends below the surface of waters.

[0045] In step SS, the prefabricated first basic structural unit is transferred from the land to the waters by using the slide 3. The volume of air in the floating and ballast tank 11 in the basic structural unit is adjusted to balance the self-weight of the basic structural unit so that the basic structural unit is kept in the floating state in the immersion waters. The one floating crane pulls the basic structural unit to the immersion position. The basic structural unit is completely suspended and submerged in water during the whole pulling process.

[0046] Specifically, half of the first basic structural unit is submerged in water through the slide 3. In this case, the self-weight of the structure is greater than buoyancy of the floating and ballast tank. À hoist cable of the floating crane is installed on the top plate of the structural unit, and the basic structural unit smoothly slides into water under the action of a pulling force of the hoist cable of the floating crane and buoyancy of water. In this case, the floating and ballast tank is completely submerged into water. The buoyancy is greater than the gravity of the basic structural unit so that the structure floats on the surface of water. Under the action of a wave 10 force and a water flow force, it is inconvenient to perform hauling. Water is flooded into the LU501867 floating and ballast tank to submerge the structural unit into water and keep the structural unit in the floating state. The floating crane hauls the structural unit to the position of an immersion foundation trench and the structural unit is ready for immersion.

[0047] In step S6, the first basic structural unit is immersed on the longitudinal-slope positioning steel plate 9. The axis positioning support bases 15 on the bottom of the first basic structural unit are completely embedded in the axis positioning holes 91 on the longitudinal-slope positioning steel plate 9. The first basic structural unit is positioned precisely in the horizontal direction and the longitudinal direction. An axis positioning hole 91 has the width of 0.405 m perpendicular to the axis direction of the passageway and the length of 1.5 m parallel to the axis direction of the passageway.

[0048] In step S7, underwater compression and connection are performed. The axial hauling locker 17 and the fixing block 16 are disposed on the top plate of the first basic structural unit and the top plate of the cast-in-place structural unit 7 at a joint respectively, are pulled to be connected so as to implement the preliminary compression and connection of rubber waterstops 14 at the first joint. The drainage pressure relief valve 13 at the lower end of the seal door of the cast-in-place structural unit 7 is opened. A pressure in a cavity enclosed by the rubber waterstop becomes lower. The seal door of the first basic structural unit compresses the joint under an external water pressure, and the rubber waterstop 14 is compressed for the second time to prevent the passage of water. Finally, the trench gap 10 between the longitudinal-slope positioning steel plate 9 of the passageway and the underwater foundation pits and connection is completed.

[0049] In step S8, the step S6 and the step S7 are repeated to sequentially complete underwater compression and connection between a second basic structural unit and the first basic structural unit, underwater compression and connection between a third basic structural unit and the second basic structural unit,..., and underwater compression and connection between the N-th basic structural unit and an (N-1)-th basic structural unit to complete the whole construction of an underwater passageway. 11

Claims

Claims LU501867

1. A method for rapidly constructing a large passageway underwater through shallow burial and cut-and-cover with no dry dock, wherein the large passageway comprises a plurality of basic structural units, each of the plurality of basic structural units is formed by integrally casting a top plate, a bottom plate, and two sidewalls, a seal door is disposed at one end of the basic structural unit and an opening is disposed on another end of the basic structural unit, a drainage pressure relief valve is disposed at a lower end of the seal door, and a rubber waterstop is disposed around an end portion of the basic structural unit at a side of the seal door; a floating and ballast tank capable of adjusting an inflow capacity and an outflow capacity is disposed in the each of the plurality of basic structural units; at least four axis positioning support bases are disposed on a bottom of the each of the plurality of basic structural units, and an axial hauling locker or a fixing block configured to be matched with the axial hauling locker is disposed on the top plate of each of the plurality of basic structural units; and the method for constructing the large passageway comprises following steps: step SI: directly prefabricating first to N-th basic structural units on a flat ground near an embankment line of passageway waters; step S2: constructing a cast-in-place structural unit, through a cut-and-cover method with a cofferdam, below the embankment line of the passageway waters, wherein the cast-in-place structural unit is configured to be connected to the first basic structural unit prefabricated in step 1, a seal door is disposed at a connection end of the cast-in-place structural unit, a drainage pressure relief valve is disposed at a lower end of the seal door, and an axial hauling locker or a fixing block configured to be matched with the axial hauling locker is disposed on a top plate of the cast-in-place structural unit; step S3: excavating an underwater foundation pit under waters where a passageway is located, installing a jack for adjusting gradients in the underwater foundation pit, and fixedly connecting a longitudinal-slope positioning steel plate onto the jack for adjusting gradients so as to position a longitudinal slope of the passageway, wherein the longitudinal-slope positioning steel plate is provided with axis positioning holes, a number and positions of the axis positioning holes correspond to a number and positions of axis positioning support bases on the bottom of each of the plurality of the basic structural units: step S4: constructing a slide at a waters embankment of a place where the basic structural units of the passageway are prefabricated, wherein a top of the slide is flush with the embankment line, and a bottom of the slide extends below a surface of waters; 12 step S5: transferring the prefabricated first basic structural unit from a land to the waters by LU501867 using the slide, adjusting a volume of air in the floating and ballast tank in the basic structural unit to balance a self-weight of the basic structural unit so that the basic structural unit is kept in a floating state in immersion waters, and pulling the basic structural unit to an immersion position through a floating crane, wherein the basic structural unit is completely suspended and submerged in water during a whole pulling process; step S6: immersing the first basic structural unit on the longitudinal-slope positioning steel plate, wherein axis positioning support bases on a bottom of the first basic structural unit are completely embedded in the axis positioning holes on the longitudinal-slope positioning steel plate, and the first basic structural unit is positioned precisely in a horizontal direction and a longitudinal direction; step S7: performing underwater compression and connection, wherein an axial hauling locker and a fixing block, which are disposed on a top plate of the first basic structural unit and the top plate of the cast-in-place structural unit at a joint respectively, are pulled to be connected so as to implement preliminary compression and connection of rubber waterstops at a first joint, and the drainage pressure relief valve at the lower end of the seal door of the cast-in-place structural unit is opened, a pressure in a cavity enclosed by the rubber waterstop becomes lower, a seal door of the first basic structural unit compresses the joint under an external water pressure, and the rubber waterstop is compressed for a second time to prevent passage of water; and step S8: repeating the step S6 and the step S7 to sequentially complete underwater compression and connection between a second basic structural unit and the first basic structural unit, underwater compression and connection between a third basic structural unit and the second basic structural unit,..., and underwater compression and connection between the N-th basic structural unit and an (N-1)-th basic structural unit to complete whole construction of an underwater passageway.

2. The method for rapidly constructing the large passageway underwater through shallow burial and cut-and-cover with no dry dock according to claim 1, wherein the basic structural unit has a longitudinal length of 22m to 25m and a weight less than or equal to 6,000 tons.

3. The method for rapidly constructing the large passageway underwater through shallow burial and cut-and-cover with no dry dock according to claim 2, wherein a number of the axis positioning support bases is four, each two of the four axis positioning support bases are arranged in parallel, and each of the axis positioning support bases has a length of 0.6m, a width of 0.4m, and a height of 0.5m. 13

4. The method for rapidly constructing the large passageway underwater through shallow burial 10501867 and cut-and-cover with no dry dock according to claim 3, wherein each of the axis positioning holes has a width of 0.405m perpendicular to an axis direction of the passageway, and a length of 1.5m parallel to the axis direction of the passageway.

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