JPH0237452B2 - KAICHUKISOKOHO - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an underwater foundation construction method used when constructing underwater concrete structures such as bridge piers, lighthouses, and dolphins.

In recent years, with the remarkable development of maritime and land transportation, construction of large-scale connecting bridges and development of port facilities have begun to take place. and,
When constructing underwater concrete structures such as bridge piers, lighthouses, and dolphin structures, conventional methods include pile foundation construction methods that use multi-columns and piles, well construction methods that excavate and sink internal soil, and hollow boxes (caisson construction). ), or the steel pipe sheet pile well method, which uses wells made by connecting steel pipes with joints.

However, all of these construction methods require complicated processes, so the construction period is long.
Another drawback is that it is susceptible to the effects of waves.

The present invention has been made in view of the above circumstances, and its purpose is to provide an underwater foundation construction method that does not require large-scale temporary equipment and can shorten the work process. Hereinafter, the present invention will be specifically explained with reference to the drawings.

FIGS. 1 to 6 show an embodiment of the present invention. First, as shown in FIG. is driven by a vibro hammer 4 through the base ring 3 and embedded. In this case, it is preferable to provide an interlocking device so that the vibrohammers 4 are interlocked with each other. Also, at this time, if the outer steel plate cell 1 is made higher than the inner steel plate cell 2 and raised to the planned height,
No formwork is required when pouring concrete. Next, as shown in FIG. 2, the inside of the inner steel plate cell 2 is filled with quality soil. By filling in the steel plate cell 2, the stability of the steel plate cell 2 can be maintained, a pile scaffolding can be secured, and a work base can be created.
Furthermore, as shown in FIG. 3, predetermined foundation piles 5 are driven between the outer and inner steel plate cells 1 and 2. This pile driving may be performed by driving a pile from outside the steel plate cell 1 using a pile ship, or by placing a pile driver on top of the filled part 6, and either method may be used. Next, as shown in FIG. 4, the earth and sand between the outer and inner steel plate cells 1 and 2 is excavated to a predetermined position, and leveled concrete 7 is placed underwater. Then, as shown in FIG. 5, predetermined reinforcing bars are assembled underwater, and standing concrete 8 is cast underwater. Finally, as shown in FIG. 6, leveled concrete 9 is placed in the upper part of the intermediate filling part 6, predetermined reinforcing bars are assembled, and upper concrete 10 is placed. Through the process described above, the underwater foundation concrete is completed.

When the underwater foundation concrete is completed using this construction method, there is no need to construct large-scale temporary facilities, and the construction period can be significantly shortened. Furthermore, since the steel plate cells 1 and 2 are cast into the underwater ground G, they are less susceptible to the effects of waves and the like, and the lateral resistance to the ground increases, which is advantageous in terms of earthquake resistance. Furthermore, even if the supporting layer is deep, construction can be carried out to the extent that the foundation piles 5 can be driven. Furthermore, since the steel plate cells 1 and 2 are installed in duplicate, there is no need to provide a formwork when pouring the standing concrete 8.

In this embodiment, the foundation pile 5 is used as a support pile, but as shown in FIG. It is also possible to use a method of pouring. In addition, as shown in FIG. 8, an injection pipe is embedded in the rising concrete 8 in advance, and a chemical solution or grout is injected into the lower part of the rising concrete 8 to perform foot hardening, thereby creating a solid foot hardening section 12. It is also possible to form a foundation and maintain stability of the foundation. Furthermore, if sufficient supporting force is obtained, but there is a risk of overturning due to horizontal force, an earth anchor 13 may be embedded and fixed in the underwater ground G as shown in FIG. 9.

As explained above, the present invention involves casting two cylindrical steel plate cells of different diameters concentrically in underwater ground with a gap provided between the two steel plate cells, and exposing the inside of the inner steel plate cell. After filling, upright concrete is placed between the two steel plate cells, and then upper concrete is placed on top of the inside filling and upright concrete, which simplifies the work process. , there is no need to install large-scale temporary equipment. Therefore, quick and stable construction can be performed. Furthermore, since the steel plate cells are cast into the underwater ground, it is possible to create a structure that is less susceptible to the effects of waves and the like, and is also strong against the ground. Furthermore, since the interior of the inner steel plate cell is filled, the stability of the steel plate cell is maintained, and it has the excellent effect of being able to be used as a work base, such as a scaffold when driving piles.

[Brief explanation of drawings]

1 to 6 are schematic cross-sectional views showing one embodiment of the present invention, FIG. 7 is a schematic cross-sectional view showing another embodiment of the present invention, and FIG. 8 is a schematic cross-sectional view showing another embodiment of the present invention. FIG. 9 is a schematic cross-sectional view showing still another embodiment of the present invention. 1, 2... Steel plate cell, 6... Filled part, 8...
Standing concrete, 10...Top concrete.

Claims (1)

[Claims] 1. Two cylindrical steel plate cells with different diameters are placed concentrically in underwater ground with a gap between the two steel plate cells, and after filling the inside of the inner steel plate cell, An underwater foundation construction method characterized by placing upright concrete between steel plate cells, and then placing upper concrete on top of the above-mentioned intermediate filling part and the upright concrete.