JPS59138696A - Sea bottom tunnel construction method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an undersea tunnel construction method, and more specifically, it is possible to select a tunnel route without being influenced by the soft ground of the sea bed, and to create a tunnel at a relatively shallow position from the sea bed surface. can be constructed and the drilling extension can be shortened,
This law also relates to an undersea tunneling method that is free from the risk of causing pollution such as seawater pollution, secondary pollution, and vibration pollution.

Known methods for constructing undersea tunnels include the bedrock tunneling method, which involves digging through bedrock, the method of burying immersed boxes, and the shield construction method.However, since the bedrock tunneling method targets bedrock, the route of the tunnel is determined by itself. There are also problems such as the fact that the rock is often located deep below the ocean floor, making it uneconomical as the length of excavation becomes long. In addition, the method using the immersed box is complicated and requires a lot of work such as bed excavation, foundation rubble, installation of the immersed box, and backfilling. There are problems such as the need to excavate the ground, improve the ground with sand piles, or build a foundation with piles, and when installing a immersed box, very careful installation accuracy is required. Furthermore, when using the shield method, when excavating soft ground, the ground to be excavated must be solidified using a chemical injection method or a freezing method, but in this case, there is a risk of water leakage or water leakage due to incomplete chemical injection. There are rough spots during expansion due to freezing, etc.゛The present invention eliminates the conventional point-of-sight points, selects a tunnel route without being influenced by the soft ground on the seabed, and constructs and excavates a tunnel at a relatively shallow position from the sea surface. The extension can be shortened, and the water sludge can be reduced every time.1. The purpose of this invention is to provide an undersea tunnel construction method that is free from the risk of secondary pollution, vibration pollution, and other pollution. The construction method of the present invention that achieves this objective is to first harden at least a portion of the submarine ground where the tunnel is to be constructed by stirring and mixing it with a slurry-like cement-based hardening material, and then excavate the ground to construct the submarine tunnel. It is characterized by:

Embodiments of the present invention will be described below based on the drawings.

In FIG. 1, reference numeral 1 indicates the seabed ground where the tunnel is to be constructed, into which a tunnel portion 2 is excavated. 3 is a soil improvement ship, which is equipped with a stirring shaft 4 that can move up and down and rotate;
As shown in FIG. 3, the stirring shaft 4 has a stirring blade 5 fixed to its tip and a slurry passage 6 provided within the shaft. Therefore, first, the soil improvement ship 6 is placed at a predetermined pouring position i.
After setting it to i1, the stirring blade 5 at the tip of the stirring shaft 4ζ is lowered from the seabed surface 7 to a predetermined depth while rotating, and when it reaches a predetermined depth, it is raised, and when the stirring blade 5 descends or rises. At the same time, slurry-like cement l-based hardener is forced into the ground 1 from the slurry passage 6.

The slurry is passed from the injection pump through the slurry passage 6,
A method that improves soft ground into solid ground by stirring and mixing it with soft soil by rotating the stirring blade 5 while pressurizing it into the ground 1, and solidifying the soft soil itself using the hardening reaction of cement (hereinafter referred to as deep mixing). processing method). A tunnel section 2 is excavated in the ground 1 hardened in this way, and a concrete lining section 7 is provided thereto to construct an undersea tunnel, as shown in FIG.

Specifically, the submarine tunnel construction method of the present invention can be implemented as follows.

That is, after the submarine ground on which the tunnel is to be constructed is hardened to the same strength as bedrock using a deep mixing treatment method, the submarine tunnel is constructed by excavating this hardened ground using a method similar to the construction of rock tunnels. I can do it. Further, by using the deep mixing method, the strength of the six parts that will become the tunnel is made stronger than the surrounding area, making it easier to excavate, and by excavating these parts, it is possible to improve the excavation efficiency. Furthermore, when hardening submarine ground using the deep mixing method, only the area around the part that will become a tunnel is hardened, and excavation efficiency is improved by excavating above the unhardened part without hardening the part that will become the tunnel. Further improvement of the results can be achieved.

The present invention is configured as described above, and after the undersea ground on which a tunnel is to be constructed is stirred and mixed with a cement-based hardening material in the form of slurry and hardened, the undersea ground is excavated to construct an undersea tunnel. As a result, the route I of the tunnel can be selected without being affected by the soft ground on the seabed.
Moreover, since the tunnel can be constructed at a relatively shallow position from the seabed surface, the length of excavation can be shortened.

Additionally, since soft ground can be hardened in its original location, there is no need to worry about seawater contamination or secondary pollution, and since it is a vibration-free construction method, there is no risk of affecting existing surrounding structures. Furthermore, unlike conventional construction methods, it is possible to harden and utilize soft ground without using large amounts of sand or gravel, making effective use of resources possible. In addition, the slurry can be used to select the hardening agent mixing ratio according to the soil condition of the ground, so the strength of the part that will become the tunnel is made easier to excavate than the surrounding area, and that part is excavated. By doing so, or by hardening only the periphery of the portion that will become the tunnel, and excavating the unhardened portion without hardening the portion that will become the tunnel, it is possible to improve the excavation efficiency.

[Brief explanation of the drawing]

FIG. 1 is an overall view showing the construction of an undersea tunnel by implementing the present invention, FIG. 2 is an enlarged view of a main part thereof, and FIG. 3 is a side view of a stirring shaft. 1... Seabed ground, 2... Tunnel section, 4... Stirring shaft, 7... Lining section. Agent: Patent Attorney Makoto Ogawa − Patent Attorney: Ken Noguchi Patent Attorney: Kazuhiko Saishita

Claims (1)

[Claims] 1.) At least a portion of the submarine ground on which the tunnel is to be constructed is stirred and mixed with a cement-based hardening material in the form of slurry to harden it, and then the ground is excavated to construct the submarine tunnel. An undersea tunnel construction method characterized by: 2. The undersea tunnel construction method according to claim 1, in which the portion that will become the tunnel is hardened to a strength that makes it easier to excavate than the surrounding area. 3. The undersea tunnel construction method according to claim 1, in which only the periphery of the portion that will become the tunnel is hardened.