JPH0613773B2 - Basic construction method for underwater structures - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a foundation construction method for an underwater structure.

<Prior art> When installing an underwater structure such as a submerged box or caisson on the water bottom, if the gap generated between the unevenness of the water bottom and the bottom surface of the underwater structure is left, the stability of the underwater structure deteriorates. It is necessary to eliminate this gap.

Generally, an injection material such as mortar or cement milk is injected between the water bottom and the underwater structure to eliminate the gap.

By the way, when injecting the injectable material in a state where the surroundings of the underwater structure are opened, the injected injecting material leaks to the side of the underwater structure.

Therefore, the following measures have been taken as a method for controlling the leakage of the injection material.

(A) A method of stacking sandbags around an underwater structure to shield it.

(B) A method of backfilling with rubble or earth and sand around the underwater structure to shield it.

(C) Method using a mortar injection bag.

<Problems to be Solved by the Present Invention> In the case of the above-described technology for eliminating each gap, it takes a considerable amount of time and labor from the submersion of the underwater structure to the shielding of the gap, and the mortar after the shielding. It takes more days to stabilize the underwater structure by injecting etc., and the construction period tends to be prolonged.

<Purpose of the present invention> The present invention has been made in view of the above points, and an object of the present invention is to effectively prevent leakage of the injectable material and to have excellent workability and to provide an underwater structure. To provide a foundation construction method.

<Structure of the Present Invention> That is, the present invention is an underwater structure for injecting an injecting material such as mortar into a gap generated between a submerged structure and a water bottom to treat the gap between the underwater structure and the water bottom. In the basic construction method of, the sheet material for preventing leakage of the injecting material having flexibility is attached in a skirt shape around the lower portion of the underwater structure, and a weight is installed under the sheet material to secure the underwater structure. Along the bottom and the bottom of the water at a fixed interval,
The lower part of the sheet material is bottomed on the water bottom to shield the gap generated between the water bottom and the underwater structure and the outside, and the pouring material is injected into the gap shielded by the sheet material to leave the weight. In the state, the sheet material is extruded to the outside by the injection material, and the extruded sheet material is brought to the bottom of the water by the weight of the injection material,
This is a basic construction method for underwater structures that prevents the injection material from leaking.

<Example> An example of the present invention will be described below with reference to the drawings.

<B> Method of shielding gaps As shown in FIG. 1, in the present invention, a water bottom 1 and an underwater structure 2 are used.
As a method of blocking the gap 3 generated between the water surface of
By attaching the strip-shaped sheet material 4 to the lower part of the underwater structure 2 in a skirt shape, the gap 3 is shielded by the sheet material 4 when the underwater structure 2 is bottomed.

Then, a method of injecting an injection material 5 such as mortar into the gap 3 shielded by the sheet material 4 to perform a basic work was adopted.

<B> Sheet material The sheet material 4 is a sheet that is flexible and has a large number of fine holes that are sized to restrict the permeation of an injection material such as mortar and allow the permeation of only water. , For example woven fabrics and nets,
A resin sheet can be used.

The attachment position of the sheet material 4 is around the lower part of the underwater structure 2,
That is, it is the bottom surface around the lower part of the side wall or near the side wall of the underwater structure 2, and the attachment method is a known method such as bonding, bolting, or curtain rail system.

A weight 6 such as a relatively heavy chain is attached to the lower end of the sheet material 4.

Further, the hem width of the sheet material 4 is about 2 to 3 times the height of the gap 3 to be generated.

Next, a method of installing the underwater structure will be described.

<1> Bottom of underwater structure Underside wall or bottom of underwater structure 2 such as a submerged box,
As described above, one end of the sheet material 4 is fixed and attached in a skirt shape.

The sheet material 4 is attached in advance in the outfitting yard.

Next, the underwater structure 2 is gently suspended.

When suspending the underwater structure 2 with the sheet material 4 attached,
The sheet material 4 is wound up by connecting a rope to the lower end of the sheet material 4 so as not to get in the way when the sheet material 4 reaches the bottom.

The underwater structure 2 is bottomed on the temporary support block 7, and a predetermined installation height is adjusted by operating a jack 8 provided on the underwater structure 2.

As a result, a gap 3 is formed between the underwater structure 2 and the water bottom 1.

<2> Shielding with sheet material (Fig. 3) When the underwater structure 2 reaches the bottom, the sheet material 4 that has been rolled up until then is dropped.

Since the weight 6 is attached to the lower end of the sheet material 4, the lower end quickly reaches the bottom and shields the gap 3 formed between the underwater structure 2 and the water bottom 1 from the outside.

<3> Injection of Injection Material (FIGS. 1 and 3) Next, an injection material 5 such as mortar is injected from the inside of the underwater structure 2 into the gap 3 shielded by the sheet material 4.

The injection material 5 injected into the gap 3 permeates into the gap 3 formed between the underwater structure 2 and the water bottom 1.

When the filling material 5 is injected into the gap 3, the water existing in the gap 3 is replaced with the filling material 5, permeates the sheet material 4, and is discharged to the outside of the sheet material 4.

When the injected pouring material 5 reaches the sheet material 4, the pouring material 5
Is deposited on the upper surface of the sheet material 4 lying on the water bottom 1 and presses the lower end of the sheet material 4 against the water bottom 1.

Since the sheet material 4 is pressed against the water bottom 1 at the lower end by the weight of the injection material 5, and the upper end of the sheet material 4 is fixed to the underwater structure 2, a bag body surrounding the gap 3 is formed. It was done.

When the pouring of the pouring material 5 is continued, tension is generated in the sheet material 4, but as the pouring amount of the pouring material 5 increases, the frictional resistance generated between the lower end of the sheet material 4 and the water bottom 1 increases, so that the sheet The lower end of the material 4 does not come out of the injected material 5.

As a result of the above, in the state where the leakage of the injection material 5 is regulated, the gap 3
The injection material 5 is injected into the entire area inside.

<Effects of the Present Invention> Since the present invention is as described above, the following effects can be obtained.

(A) Since the self-weight of the injection material acts on the upper surface of the sheet material and acts as a sandwiching force of the sheet material between the sheet material and the water bottom, it is possible to effectively prevent the sheet material from slipping out and leaking the injection material.

(B) Since the flexible sheet material receives the weight of the injecting material and press-bonds following the shape of the water bottom surface, even if the water bottom surface has irregularities, high sealing performance can be secured.

(C) The injection material can be used economically, and since the work of preventing the injection material from leaking out in water is not required, the workability is better than that of the conventional method.

[Brief description of drawings]

FIG. 1: Explanatory diagram of an embodiment according to the present invention FIG. 2: Explanatory diagram when bottoming an underwater structure and shielding a gap with a sheet material FIG. 3: Explanatory diagram when injecting an injectable material

Claims (1)

[Claims] 1. A basic construction method for an underwater structure, comprising injecting an injection material such as mortar into a gap formed between a submerged structure and a bottom of water to treat the gap between the underwater structure and the bottom of the water. A flexible sheet material for preventing leakage of the injection material is attached around the lower part of the underwater structure in a skirt shape, and a weight is installed under the sheet material, and the underwater structure is attached to the bottom surface and the water bottom. The bottom of the sheet material is bottomed at a fixed interval, and the bottom of the sheet material is bottomed on the water bottom to shield the gap generated between the water bottom and the underwater structure from the outside, and is injected into the gap shielded by the sheet material. Injecting material, extruding the sheet material outside with the weight left with the injecting material, and causing the extruded sheet material to reach the bottom of the water by the weight of the injecting material to prevent leakage of the injecting material The basic construction of an underwater structure Law.