JPS58127834A - Setting of caisson - Google Patents

Abstract

PURPOSE:To enable to exactly set a caisson withot sidewise movements, etc., by a method in which plural vertically piercing injection pipes are provided to a caisson, the caisson is set on a mound, and then a hydraulic material is injected into the injection pipes and packed in apertures. CONSTITUTION:Plural injection pipes 3 are provided in desired places of a caisson in such a way as to pierce vertically the caisson, the caisson 2 is set on a mound 1, and then a hydraulic material 9, e.g., cement mortar, etc., is injected into the injection pipes 3 to fill up the aperture between the caisson 2 and the mound 1 as well as the injection pipes 3. Since the aperture between the caisson 2 and the mount 1 is removed and the hydraulic material 9 injected from the injection pipes 3 plays the role of a pile, the setting of the caisson 2 without sidewise movements due to tidal wave, etc., can be exactly attained.

Description

[Detailed Description of the Invention] The present invention provides a method for installing caisson, and more particularly, a method for constructing a caisson, for example, a breakwater quay wall, etc.
This invention relates to a method of installing a caisson whose upper part projects above the water surface on a mound provided at the bottom of the water.

For example, when constructing a breakwater using a box caisson, a mound is set up on the seabed using rubble, etc., the caisson is floated on the sea surface and towed above the mound, water is poured inside and it sinks onto the mound, and then Instead, the caissons are filled with solid heavy objects such as concrete and earth and installed on mounds, and the frictional force between them and the mounds prevents the caissons from moving laterally due to waves.

In order to increase the frictional force between the caisson and the mound, it is necessary to increase the coefficient of friction between them or to increase the total weight of the caisson and the solid weight packed inside it. However, in the case of a normal rubble mound, the top surface of the mound is uneven and the contact area with the caisson is considerably smaller than the bottom area of the caisson, so the coefficient of friction is not very large. Therefore, in order to reliably prevent the caisson from moving laterally relative to the rubble mound, it is necessary to increase the size of the caisson, increase the amount of solid heavy objects packed inside the caisson, and use solid heavy objects with high specific gravity.
It is necessary to increase the total weight of the caisson and the solid heavy object, which increases the costs required for manufacturing the caisson, transporting the caisson, and procuring and transporting the solid heavy object. Especially in the case of steel caissons,
The coefficient of friction between the caisson and the mound is even smaller than that of a reinforced concrete caisson, and in order to obtain the same frictional force as a concrete caisson, the total weight of the caisson and solid heavy object must be increased by approximately 50% compared to the case of a concrete caisson. be.

This invention was made in view of the above-mentioned circumstances, and it reliably prevents lateral movement of the caisson by increasing its resistance against waves, etc., without particularly increasing the total weight of the caisson and the solid heavy object. The purpose is to provide a rational caisson installation method that can be used.

In the caisson installation method according to the present invention, when a caisson whose upper part protrudes above the water surface is installed on a mound provided at the bottom of the water, a plurality of injection pipes passing through the caisson vertically are provided at required positions of the caisson. is submerged on the mound, and the hydraulic material is press-fitted from the upper end of the injection pipe.
It is characterized by filling the gap between the mound and the caisson and the inside of the injection pipe.

The caisson is generally a box caisson made of steel or reinforced concrete, and the mound is generally made of rubble, but the present invention can also be applied to different types of caissons and mounds.

Furthermore, although mortar, concrete, etc. are commonly used as hydraulic materials, other materials can also be used.

The present invention will be described in detail below with reference to the drawings.

Figures 1 and 2 show a steel box caisson (2) installed on a rubble mound (1) on the seabed, with the upper part of the caisson (2) protruding above the sea surface. Inside the caisson (2), a plurality of mortar injection pipes (3) are provided that pass through the caisson (2) vertically. The upper end of each injection pipe (3) is connected to a circular recess (4) formed in the soil surface of the caisson (2).
) and is provided with a horizontal flange (5) (third
(see Figures and Figure 4).

Further, the lower end of each injection tube (3) is slightly flared. Although not shown, the upper surface of the caisson (2) is provided with a plurality of hatches for inserting heavy solid objects.

The above caissons are installed as follows.

That is, the caisson (2) manufactured at a land facility such as a shipyard or a floating dock is floated on the sea surface and towed to the installation location. There are rubble stones (6
) with a mound (1) and a caisson (2).
) is towed above the mound (1), then water is poured inside and it sinks onto the mound (1). Next, solid heavy materials (7) such as earth and sand are introduced through the hatch and packed inside the caisson (2), and the caisson (2) is placed at a predetermined position on the mound (1).
) will be installed. At this time, since the upper surface of the mound (1) is uneven, many gaps are created between the ivy mound (1) and the caisson (2). Next, as shown in FIG. 3, the tip of the mortar pressure pipe (8) from a land facility or a work boat (not shown) is connected to the upper end of the injection pipe (3), and the mortar (9) is is press-fitted into the injection pipe (3) to fill the gap between the mound (1) and the caisson (2) and between the rubble stones (6) on the top of the mound (1). Fill. Once the mortar (9) has been press-fitted, remove the mortar pressure pipe (8) and
) on the flange at the top of the injection tube (3) (
5).

The gap between the mound (1) and the caisson (2) and (
6), and as these come into contact with the entire bottom surface of the caisson (2), the friction coefficient of the candy between the mound (1) and the caisson mower 2) becomes large, and the caisson (2) and the solid heavy object (7)
), the total weight of the mortar ( The tenth end of 9) is integrated with the caisson (2) and enters the gap between it and the mound (1), producing the same effect as driving a stake into the mound (1). , the resistance against waves, etc. becomes even greater.The dimensions, number, arrangement, etc. of the injection pipes (3) should be determined as appropriate, taking into consideration the magnitude of external forces such as waves, the dimensions of the caisson (2), the weight of the casson, etc. It is determined.

In addition, in the case of a reinforced concrete caisson, the hydraulic material such as mortar filled between the mound and the caisson is integrated with the mound and firmly fixed to the bottom of the caisson, which increases its resistance to waves. becomes very large.

According to the caisson installation method of the present invention, as described above, the gap between the mound and the caisson is filled with a hydraulic material, and the hydraulic material filled in the injection pipe acts as a pile. Even without particularly increasing the total weight of the caisson and the solid heavy objects packed inside it, the resistance against waves and the like increases, and lateral movement of the caisson can be reliably prevented.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and Fig. IJ1 is a cross-sectional view showing a caisson installed on a mound by the method of the present invention, Fig. 2 is a plan view of the same, and Fig. 3 shows the injection during press-in of hydraulic material. FIG. 4 is an enlarged cross-sectional view showing the upper end of the tube, and is a drawing corresponding to FIG. 3 showing a state in which the lid is fixed to the upper end of the injection tube. (1)...mound, (2)...caisson, (3)
... Injection pipe, (9) ... Mortar (hydraulic material). that's all

Claims (1)

[Claims] When installing a caisson with its upper part protruding above the water surface on a mound at the bottom of the water, multiple injection pipes are installed at the required positions on the caisson to penetrate the caisson up and down. A caisson installation method characterized by press-fitting a hard material from the upper end of the injection pipe to fill the gap between the mound and the caisson and the inside of the injection pipe.