JPS6178924A - Temporary coffering work for dry dock - Google Patents

Abstract

PURPOSE:To perform dry construction of a dock by a method in which a caisson for dry dock gate is temporarily set as a temporary coffering dam, water in the dock is discharged, the dry dock is constructed, and water is charged to used the caisson as a gate again. CONSTITUTION:A caisson 1 made as the gate of a dry dock is towed to a setting position for temporary coffering dam of the dry dock and settled. A water stop steel plate 3 is driven on the outside of the caisson 1. Sea water in the dry dock 4 is drained, and main structures 5 for the dry dock 4 are constructed on dry basis. Sea water is again charged into the dry dock 4, the steel plate 3 is removed out, and the caisson 1 is again floated and settled into a position of gate. Dock can thus be constructed on dry basis without needs to provide any specific dam.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is a method for temporarily constructing a cofferdam body to temporarily block seawater when constructing a dry dock for building ships or marine structures near the shoreline. This is related to the temporary cofferdam method.

[Prior art and its problems]

It is advantageous in terms of quality, cost, construction period, safety, etc. to construct the main structures of a dry dock (culvert walls, culvert bottom, first ζ structure at the culvert mouth, etc.) in a dry state. For this reason, temporary embankments are usually installed using earth and sand or steel sheet piles to block the seawater. This embankment body will be removed after the above-mentioned main structure is completed, a gate is installed, and a water test is conducted.

As this type of temporary cofferdam construction method, the construction method described below has been commonly used in the past.

■ First, earth and sand will be thrown into the sea at sea and an earth dam will be built. If necessary at this time, steel sheet piles for water supply will be driven into the earth dam.

Then, the seawater inside the upper dam, that is, inside the culvert, will be drained and the necessary main structures will be constructed in a dry state.

The earth and sand inside the upper dam will then be removed to the required water depth.

■ A mount of earth and sand will be set up as a foundation at the required depth in the sea, and steel sheet piles will be placed in parallel and driven into this mound at sea. Then, the heads of the art style sheet piles are tied together with tension material, and earth and sand is filled between the steel sheet piles to form the embankment body.

Next, the seawater inside the dam, that is, inside the culvert, is drained and the necessary main structures are constructed in a dry state.

Afterwards, the earth and sand on the embankment body will be removed to the required water depth, and the steel sheet piles will also be removed.

However, method (■) requires a large amount of earth and sand to construct the embankment body, and also requires a place to remove this earth and sand.

There is also a risk of marine pollution due to the large amount of sediment. Furthermore, during construction, the sea area needs to be calm as earth and sand will be thrown in, and the sea area occupied by the embankment body is large.

The construction method (■) requires less earth and sand than the construction method (■), but it also requires a considerable amount of earth and sand due to the creation of mounds, etc. This means that the risk of marine pollution is lower than in ■, but it still remains to some extent.

Also, although the occupied sea area is smaller than the construction method (①), a considerable area is still required to construct the mound.

Furthermore, in order to drive the steel sheet piles, there were other problems, such as the need for stronger ground than in method (2).

[Purpose of the invention]

This invention was devised in view of the above-mentioned circumstances, and its purpose is to eliminate the need to throw earth and sand into the sea, eliminate the risk of polluting the sea area, and reduce the area of sea area occupied by the embankment. The purpose of this invention is to provide a temporary cofferdam construction method for dry docks.

[Means for solving problems]

According to the construction method of this invention, a caisson manufactured for the gate of the dry dock is sunk during construction of the main structure of the dry dock and used as a temporary cofferdam body for blocking seawater. After the construction of the main structure, the caisson will be floated and fixed at the original gate installation position.

〔Example〕

The installation state of a temporary coffering embankment body according to this invention construction method will be explained below with reference to an illustrated example.

First, a gate caisson 1 made of Re is manufactured at a caisson yard (not shown) and towed to a location where a cofferdam body is installed. (See Figure 1) Next, when the caisson 1 is towed to a predetermined position, the caisson 1 is sunk, and a water-stop steel sheet pile 5 is driven at the end of the caisson 1 on the open sea 2 side to form a temporary cofferdam body. (See Figure 2) Next, seawater from the side of the caisson 1 that will become the culvert 4 is drained to the open sea 2, and the main main structure S is constructed in a dry state, and the water supply steel sheet pile 6 is driven. do. (See Figure 5) After the construction of the main structure 5 is completed, water is injected into the culvert 4 side and the water supply steel sheet pile 6 is removed. After that, caisson 1, which was used as a temporary cofferdam body, was floated again.
Set the gate in the desired position and use it as a dry dock gate. (See Figure 4) [Effect of the invention] , -/IN yt+tll IJ lit
L/I'L L-;, f: 11.1
It has the effects described in rDJ+, Gosu, and Hutt.

By using the caisson manufactured for the dry dock gate as a temporary coffering embankment body for seawater isolation during construction of the dry dock permanent structure, the permanent structure can be constructed in a dry state without the need for a special embankment body.

Therefore, there is no need for earth and sand to install the embankment body, so there is no risk of contaminating the sea area, and there is no need to throw earth and sand into the sea, so the work for installing the embankment body can be carried out even when the sea is not calm.

In addition, the temporary cofferdam body and dry dock cage can be installed by simply repeating the floating, moving, and sinking of the caissons, making construction easier and shortening the construction period. Since this does not require the aforementioned earth and sand, the overall construction cost can be reduced.

Furthermore, by using only a caisson as an embankment body, the sea area occupied is only the size of the caisson, and the area area can be made smaller than when constructing an embankment vessel using earth and sand.

[Brief explanation of drawings]

FIGS. 1 to 4 are process diagrams showing the installation state of a temporary cofferdam body by the construction method of this invention. 1. Caisson, 2. Open sea, 5. Water-stop steel sheet pile, 4.
・Inside the culvert, 5. Main structure, 6. Water supply steel sheet pile.

Claims (1)

[Claims] A cofferdam construction method in which a temporary cofferdam body for seawater isolation is temporarily installed prior to construction of a permanent structure in a dry dock culvert, in which a caisson is manufactured for the gate of the dry dock and is towed and sunk. Therefore, it is temporarily constructed as the embankment body, and after the permanent structure is constructed, it is floated to the gate installation position,
A temporary cofferdam construction method for dry docks that is characterized by moving and fixing.