JPS5930880B2 - How to make a sunken burial box - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing an immersed box for an immersed tunnel.

Those with immersed boxes for immersed tunnels have a width of 30 to 40 mm.
As it is a large ship with a length of approximately 120 m and a weight of nearly 10,000 tons, it is necessary to construct a large-scale dedicated dock or use a shipbuilding dock. We are facing a difficult problem.

Conventionally, the method used was to use a dock to manufacture an all-concrete immersed box and then launch it into the water after it had hardened.
Although this method has been implemented, it takes a long time to manufacture the immersed boxes, which results in poor dock operation efficiency, prolongs the tunnel construction period, and increases the cost of the immersed boxes and, by extension, the tunnel construction costs.

Instead of the above construction method, the outer jacket of the immersed box is made of a steel shell, the steel shell is first built at the dock, the shell is launched, it is towed to a quay prepared for that purpose, it is held there, and the shell is lowered. Floor slabs, middle walls, side walls,
A method of completing the immersed box by sequentially pouring concrete such as ceiling slabs was adopted, and by placing heavy concrete and hardening it at a location other than the dock, it became possible to In addition to increasing the operating rate, the steel shell was considered to be extremely effective as a waterproofing and earthquake countermeasure for the tunnel after it was buried.

The ζ steel shell used in the early stages of this steel shell construction method had a completely enclosed structure, and at the holding quay, the buoyancy acting on the bottom steel plate of the steel shell caused uneven deformation of the steel shell, and during concrete pouring. Concrete is heavy (and does not have full strength at the time of pouring), which further causes secondary nonuniform deformation of the steel shell. Consideration must also be given to reducing the occurrence of uneven deformation as much as possible by adjusting the order of pouring.

Furthermore, when pouring concrete for the ceiling slab, it is necessary to fill the narrow space between the formwork and the ceiling steel plate of the steel shell, making the work difficult. It is structurally difficult to remove the harmful residual laitance that floats to the surface, and it is unavoidable to inject mortar between the concrete and the ceiling steel plate of the steel shell without removing the laitance. There are many drawbacks, such as the fact that work inside the steel shell is a poor working environment due to the heat generated when the concrete hardens due to pouring a large amount of concrete into the nearly airtight steel shell.

To address the above-mentioned drawbacks, in Japanese Patent Publication No. 50-29565,
By using an open-top steel shell as opposed to the fully enclosed steel shell described above, it is possible to eliminate difficulties in concrete filling and laitance when pouring concrete for the ceiling and floor using the above-mentioned construction method.
It eliminates drawbacks such as poor working environment and enables careful pouring work under blue ceilings.After that, the ceiling steel plate of the steel shell is installed and mortar is filled between the top surface of the concrete below and the immersed box is constructed. Work on the quay has been completed.

Despite the above-mentioned improvements, the problem of deformation of the original steel plate of the steel shell during concrete pouring for the sub-slab still remains unresolved.

The present invention aims to solve the above-mentioned unresolved obstacles, and at the same time, to provide a high-quality immersed burial box at a lower cost by significantly reducing the amount of steel required, and by improving the steel structure and manufacturing process. The objective was achieved by improving the

The key point is that when producing a submerged box on the water, first the raw steel plates are placed watertight and horizontally on the bottom of the dock, and column-shaped bending members are installed on both sides of the web of the cross-section shaped girder. , constructing a side girder equipped with a bracket-like connecting device with a number of stud dowels planted in the lower part of the bending member inside the submerged box, placing the side girder on both sides of the raw steel plate, and forming the side girder with the ■-shaped cross section. The lower flange of the girder and the raw steel plate are watertightly welded, a bulkhead is provided in the longitudinal direction of the raw steel plate to form a steel shell, and then concrete for the lower deck is poured on the master plate of the steel shell. , wait for the concrete of the lower base plate to harden, and then launch the immersed product into a submerged box;
After that, we decided to perform the process of pouring concrete for the inner walls, side walls, ceiling slabs, etc. necessary for the immersed box structure.

According to this method, the raw steel plates of the steel shell are supported by the bottom of the dock and are laid flat, so even when the sub-floor concrete is poured, they will not deform due to the weight of the sub-floor concrete. ■ By arranging a bracket-like connecting device with a shear connector function to connect the steel girder with a cross-sectional shape and the highly rigid sub-slab concrete, the steel girder generated at the joint will be below the water line. The immersion box has strong rigidity by strengthening the bond against the bending force caused by the water pressure pushing the immersion box inward and the shearing force that transfers the weight of the ceiling slab and side walls of the immersion box to the concrete subfloor slab. It is possible to reduce the amount of steel by making it a box and not contributing to the strength of the original steel plate.

Details of the method of the invention are described below with reference to illustrated embodiments.

Figure 1 is a schematic perspective view of a partially fragmented ceiling of the immersed box.
1 shows the bulkhead, which was removed when the tunnel was opened for construction procedures such as transporting, sinking, and connecting the immersed box to the adjacent surface, 2 shows the lower floor slab, 3 shows the side wall, and 4 shows the ceiling slab. .

FIG. 2 is a partial cross-sectional view of a submerged burial box in the process of being manufactured by the method of the present invention, and FIG. 3 is an enlarged view of the lower left part of FIG. 2.

Raw steel plates I, which are welded and watertightly integrated, are placed horizontally on the bottom surface 5 of the dock at appropriate spacing pieces 6.

Consisting of web 9, lower flange 10, and upper flange 11■
Column-shaped bending members 12 are provided on both sides of the web 9 of the type cross-section type girder, and a stud dowel 14'd that serves as a shear connector is installed at the bottom of the bending members 12 inside the submerged box. A stringer 8 equipped with a bracket-shaped connecting device 13 planted in J is constructed and placed on both sides of the raw steel plate 70, and the end of the lower flange 10 and the end of the raw steel plate 7 are made watertight by the weld seam 15. Weld as shown.

By providing the bulkheads 1 at both ends of the raw steel plate 7 in the longitudinal direction, the steel shell, which is the main part of the structure of the present invention, is completed in the dock, resulting in the appearance shown in FIG. 4.

After the steel shell is completed, reinforcing bars for the concrete 16 for the lower deck slab are placed on the original steel plate 7 in the same position in the dock, and concrete is poured to form the lower deck 2. The configuration is as shown in Figure 5.

Taking advantage of the number of days that the lower floor concrete 16 is curing, the middle wall concrete 17 is connected to the lower floor concrete 16.
It is effective for the progress of the process to proceed with the construction of reinforcing bars for the concrete side walls 18 as much as possible within the circumstances.

After waiting for the concrete 16 for the lower floor to harden, the semi-finished immersed container is launched.

The stifling water at this time was as shown in Figure 6 (0.54 m corresponding to the weight of the steel shell alone and 3.37 m for the concrete of the lower deck, totaling 3.91 m.

The immersed box containing recycled products will be towed to the quay where preparations are being made for concrete pouring work on both layers, where it will be deported.

By placing the middle wall concrete 17, the hiccup will be 4.26 m as shown in Figure 7, and by pouring the side wall concrete 18 in the next step, the hiccup will be reduced to 4.26 m as shown in Figure 8.
It increases to 34,771.

Ceiling floor slab concrete) 19 pouring & ζ steel shell ceiling steel plate 2
Since the work was carried out without the installation of steel reinforcing steel, reinforcement was laid and placed, and laitance was removed carefully in a favorable environment. By installing the ceiling steel plate 20 and filling with mortar, the dripping was eliminated as shown in Figure 9. <8.95m.

After removing the support for pouring the concrete ceiling slab H9 and cleaning the inside, the immersed box was completed and looked like Figure 10.
Standby for towing to the buried site.

According to the structure of the present invention, the side girder 8 constituting the steel shell and the concrete lower deck 16 are firmly connected by the connecting device 13 to serve as the center of rigidity of the submerged box, and the raw steel plate 7 is connected to the concrete lower deck 16. Conch! J-)16 It mainly serves as the lower formwork during pouring and for waterproofing, and there are few expectations for its strength.
There is no need for a thick steel plate, and the ceiling steel plate 20 does not serve as a formwork, and it is even possible to eliminate it and replace it with the ceiling slab concrete 19 by waterproofing.

As described above, according to the structure of the present invention, it is possible to save 40 to 50% in the amount of steel required in the trial design compared to the case of the prior art.

According to the method of the present invention, in order to completely eliminate the need to consider the deformation of the raw steel plate 7, the thickness of the raw steel plate 7 is allowed to be reduced, and when pouring concrete for the sub-slab 16, The advantages of using the prior art steel shell as an open-top type eliminates the need to subdivide the pouring locations and adjust the pouring order in order to prevent secondary deformation of the raw steel plate 7 due to the weight of Together, the time and effort required to produce immersed boxes can be greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view of the immersed burial box, FIG. 2 is a partial cross-sectional view of the immersed burial box made by the method of the present invention, FIG. 3 is an enlarged view of the lower left corner of FIG. 2, and FIGS. Figure 10 is an explanatory diagram of the submerged box manufacturing process. 1... Bulkhead, 2... Lower floor slab, 3... Side wall, 4... Ceiling floor slab, 5... Bottom of dock, 6...
Spacing piece, 7... Raw steel plate, 8... Side girder, 9... Web, 10... Lower flange, 11... Upper flange, 1
2... Resistance bending material, 13... Connecting device, 14... Studgeher, 15... Welding seam, 16... Subfloor slab concrete, 17... Middle wall concrete, 18... Side wall Concrete, 19...Ceiling slab concrete, 2
0...Ceiling steel plate.

Claims (1)

[Claims] 1. When manufacturing a submerged box on the water, first, a steel plate bottom is placed watertight and horizontally on the bottom of the dock, and pillar-shaped bending members are installed on both sides of the web of the type cross-section girder. The side girder is equipped with a bracket-like connecting device with a number of stand dowels planted in the lower part of the inner bending member, and the side girder is arranged on both sides of the bottom steel plate, and the lower flange of the ■-shaped cross-section girder is constructed. and a bottom steel plate are welded watertightly, a bulkhead is provided in the longitudinal direction of the bottom steel plate to form a steel shell, and then a subfloor concrete is poured on the bottom steel plate of the steel shell, and the bottom steel plate is welded to the bottom steel plate in a watertight manner. 1. A method for producing a submerged box, which comprises: waiting for the submerged box to harden, then launching the product into the submerged box, and then carrying out the process of pouring concrete for the inner walls, side walls, ceiling slab, etc. necessary for constructing the submerged box.