JPS60159224A - Method of installing caisson - Google Patents

Abstract

PURPOSE:To improve working efficiency, by a method wherein a caisson is sunk for installation on a levelling foundation in water with underwater concrete located therebetween in a condition in which the concrete is before curing. CONSTITUTION:Underwater concrete 4 is placed in a position, where a caisson 1 is installed on a levelling foundation 3, by guiding the concrete through a tremie 9 extending from an underwater concrete plant ship 5 with the aid of a diver 6 in a manner that the concrete is placed up to a level where the unevenness on the surface of the foundation 3 is concealed. After the caisson 1 is tugged to a site by a tugging ship before the concrete 4 is cured, the caisson 1 is sunk for installation on the foundation 3. Thereafter, overlay stones 8 are placed around the caisson 1. After the concrete 4 is previously placed in a netty bag body placed on the bottom of the caisson 1, the caisson 1 may be sunk for installation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for installing a caisson that is sunk on a rubble foundation constructed underwater when constructing a breakwater or the like.

[Prior art]

Conventionally, when constructing a breakwater, a structure called a hybrid levee was constructed by constructing a rubble foundation in the planned water, and then constructing a superstructure using caissons, concrete blocks, cellular blocks, etc. on top of it. It is economical and widely adopted.

However, in this case, in order to sink the caisson horizontally, the rubble thrown into the sea must be leveled, and this work is done by divers, which is inefficient and difficult to do, especially in deep water. The problem is that it is also very bad.

Therefore, it is possible to perform this work of leveling the rubble mechanically, but this has the drawbacks of being expensive and lacking in reliability due to the large-scale leveling machine.

[Purpose of the invention]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method of installing a caisson with good workability by omitting the work of leveling the rubble during the construction of the conventional hybrid embankment.

[Structure of the invention]

That is, the caisson installation method of the present invention is characterized by sinking the caisson on a rubble foundation constructed underwater while interposing underwater conocrete in a state before hardening. Another effective method is to place the underwater concrete into a mesh bag attached to the bottom of the caisson when the caisson is being sunk.

〔Example〕

Each embodiment to which the caisson installation method of the present invention is applied will be described below with reference to the drawings, and in each embodiment, the same parts are indicated by the same part numbers.

First, in Embodiment 1 shown in FIGS. 1, 2, and 3, when installing the caisson 1 that has been floated to the sea surface W and towed onto the rubble foundation 3 constructed underwater on the lake bed G, Then, a diver 6 guides the caissons 10 on the top surface of the rubble foundation B from the plant ship 5 through the tremie pipe 9 and pours the underwater concrete 4 by force-feeding or gravity.

At this time, the underwater concrete IJ-1-4 is placed until the unevenness caused by the protrusion of the rubble on the surface of the rubble foundation 6 is covered, and before the underwater concrete 4 hardens, the caisson 1 is placed as shown in Fig. 2. The caisson 1 is towed by a tugboat 7 to the installation position and is submerged by pouring water into its box chamber, and the caisson 1 is submerged on a rubble foundation 6 with underwater concrete 4 interposed therebetween.

As a result, as shown in Fig. 3, the underwater concrete 4 is pressed onto the embankment surface of the rubble foundation 6 by the weight of the caisson 1 body, filling in the unevenness of the surface, filling the voids in the surface layer, and bonding the caisson 1 and the rubble foundation 6 together. After the caisson 1 is sunk, a covering stone 8 is further constructed around the caisson 1, and the installation work of the cane 1 is completed.

Next, in the second embodiment shown in FIGS. 4 to 15, when the caisson 1 is sunk on the rubble foundation 3 with the underwater concrete 4 interposed, similar to the first embodiment, the underwater concrete 4 is It is placed in advance in a mesh bag 2 attached to the bottom of the caisson 1 as shown in FIG.

This mesh bag (4-2) is formed into a relatively flexible structure made of synthetic fibers such as nylon, and has the shape shown in Fig. 9, and is designed to handle the weight of the underwater concrete 4 to be cast inside. It is strong enough to endure.

Moreover, the upper end of the periphery of this mesh bag 2 is shown in FIGS. 10 and 11.
Afangle 12 manufactured by 'i@' is fixed by a steel angle 12 shown in the figure, and bolted steel rods 11 are also attached in advance around the bottom of the caisson 1 when the caisson 1 is constructed, and the mesh bag body 2 is attached to this. This mesh bag 2 is attached to the bottom surface of the caisson 1 by attaching it with a holding plate 16 and bolts 14.

The mounting portion of the steel angle 12 is a portion a-d-e-h-a at the upper end of the periphery of the mesh bag 2 in FIG.

In addition, in order to prevent this mesh bag (*2) from sagging and damage during pouring of underwater concrete 4,
Gas pipes 16 as shown in FIGS. 12 and 13 are provided in the portions of and c-f, and these gas pipes 16 are connected to the steel rods 15 that were attached when the caisson 1 was constructed. Hang the top end of the

Note that it is preferable that the mesh of this net-like bag 2 be used as a standard mesh of lQmi or outside.

Then, the caisson 1 with the mesh bag 2 attached to its bottom is towed onto the rubble foundation 6 by a tugboat 7 as shown in FIG. 4, and stopped at its installation position as shown in FIG.
As shown in FIG. 6, underwater concrete 4 is placed in advance into the mesh bag 2 via an underwater concrete plant ship 5 and a sytlemy pipe 9.

When pouring the above-mentioned underwater concrete 4, as shown in FIGS. 14 and 15, the concrete filling pipe 17 with a groove, which was previously attached to the bottom of the caisson 1 when it was constructed, is used to place the concrete in the caisson 1. This is done with consideration given to ensuring that the situation is not tilted.

Therefore, once the underwater concrete 4 has been placed, if water is poured into the garden before the underwater conocrete 4 hardens and the concrete is deposited on the rubble foundation 6, the underwater concrete 4 filled in the mesh bag 2 can be interposed. However, the caisson 1 presses the underwater concrete 4 onto the plate surface of the rubble foundation 3 by its own weight, and as in the first embodiment, the caisson 1 and the rubble foundation are brought into close contact.

This Embodiment 2 is suitable for cases where the planned water depth for constructing a hybrid dyke for caisson 1 is large, or when the influence of the current on the lake bottom is large, or when the shape of cane/1 is too sharp, or when underwater co/II is used.
-G4 O This is particularly effective when the amount of pouring is large.

Further, as the underwater concrete 4 used in the present invention, for example, Japanese Patent Application Laid-open No. 57-123850, Japanese Patent Laid-Open No. 58-6
9760, which is a commonly used underwater concrete in which cement, sand and aggregate do not separate in water, can be used.

〔Effect of the invention〕

Therefore, if the cane/cane installation method of the present invention is adopted, the adhesion between the caisson and the board surface of the rubble foundation will be improved by the underwater concrete interposed between them. It is now possible to completely omit the rubble leveling work that has been considered indispensable for construction, reducing the number of divers, and eliminating the need for large-scale leveling machines, making it possible to construct caisson mixed plates economically. It has many advantages, such as being able to significantly shorten the construction period.

[Brief explanation of drawings]

, FIG. 1, FIG. 2, and FIG. 3 are a series of explanatory views explaining the caisson installation method in Embodiment 1 of the present invention, and FIG. 4, FIG. 5, FIG. 6, and FIG. 8 is an enlarged perspective view of the caisson in FIG. 4, FIG. 9 is a perspective view of the mesh binding in FIG. 8, and FIG. Figure 11 is an enlarged perspective view of the steel angle part that fixes the upper edge of the mesh bag.
Fig. 12 is an enlarged perspective view of the gas pipe suspending the central part of the mesh bag shown in Fig. 9, and Fig. 13 is a cross-sectional view showing the steel angle shown in the figure attached to the caisson. 14 and 15 are a series of sectional views illustrating the underwater concrete placement procedure shown in FIG. 6. 1...Caisson, 2...Mesh bag, 6...Rubble foundation, 4...Underwater concrete. Agent Patent Attorney Shin Ogawa - Patent Attorney Masaru Noguchi Patent Attorney Kazuhiko Saishita Figure 1 Figure 8 Figure 9 @ Figure 12 Figure 13

Claims (1)

[Scope of Claims] 1. A method for installing a caisson, which comprises sinking the caisson onto a rubble foundation built underwater, with underwater concrete interposed in a state before it hardens. Z When the caisson is submerged on the rubble foundation built underwater, with the underwater concrete interposed in its unhardened state, the underwater concrete (IJ) is poured into the mesh bag attached to the bottom of the caisson. A method for installing a caisson according to claim 1.