JPH0437238B2 - - Google Patents

Description

[Detailed Description of the Invention] <<Industrial Application Field>> The present invention relates to a method for launching a shield excavator in an undersea tunnel construction method, and in particular, to a method for launching an immersed tunnel in which the shield excavator is installed at an angle with respect to the undersea ground. This invention relates to an improved method for installing a shield excavator when the shield excavator is launched through a tunnel.

<<Prior Art>> As is well known, as a type of method for constructing an undersea tunnel, a method for constructing a tunnel using a shield tunneling machine has been provided.

In this type of construction method, the shield tunneling machine is usually launched from a starting shaft that is excavated vertically into the ground, approximately parallel to the horizontal level of the tunnel to be constructed.

However, in this starting method, the starting shaft must be constructed to a considerably deep depth, resulting in a large economic disadvantage.

Therefore, for example, as disclosed in Japanese Patent Application Laid-Open No. 10396/1983, a method has been proposed in which the shield tunneling machine is launched from the starting shaft at an angle toward the seabed surface. According to this method, the starting shaft is There is no need to build to a very deep depth.

However, the starting method shown in this publication has the following problems.

<Problems to be Solved by the Invention> In other words, according to the method for starting a shield excavator disclosed in the above publication, a shield is placed in advance in an element at the tip of an immersed tunnel that is sunk diagonally with respect to the starting shaft. It has a built-in digging machine.

This not only increases the weight of the element and makes it difficult to tow it to the site of burial.
In order to make it easier to launch, the shield tunneling machine is installed biased towards the front end within the element.
It was also difficult to control the attitude during submersion.

Furthermore, in order to incorporate the shield tunneling machine into the element, the assembly to the element must wait until the shield tunneling machine is completed, which is disadvantageous in terms of construction period.

This invention was made in view of these circumstances, and its purpose is to provide a shield tunneling machine for undersea tunnel construction, which can be easily towed and submerged, and which is also advantageous in terms of construction period. The goal is to provide a starting method for

<Means for Solving the Problems> In order to achieve the above object, this invention installs an immersed tunnel in an inclined state from a starting shaft toward the seabed ground, and a shield tunneling machine is installed from the tip of this immersed tunnel. In the method for starting, after the immersed tunnel is sunk, a temporary loading tube extending above the sea surface is installed in communication with the tip of the tunnel, and the shield tunneling machine is suspended and installed at the tip through the loading tube. It is characterized by

<<Operation>> According to the method for launching a shield excavator having the above configuration, the shield excavator is launched directly into the seabed via a temporary loading pipe that extends to the sea surface and is formed in communication with the tip of the submerged tunnel. Therefore, towing and sinking of the immersed tunnel becomes easier.

<<Example>> Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIGS. 1 and 2 show an embodiment of a method for starting a shield excavator in an undersea tunnel construction method according to the present invention.

In the starting method shown in FIG. 1, first, as shown in FIG.

In this case, the depth of the shaft 14 may be relatively shallow without reaching the submarine ground 10.

Once the shaft 14 is formed, an immersed tunnel 16 is constructed between the shaft 14 and the submarine ground 10.

The immersed tunnel 16 is sunk in an inclined state between the vertical shaft 14 and the submarine ground 10 along the planned line of the submarine tunnel 18, and these are fabricated on the ground as elements 16a to 16e divided into appropriate lengths, and then It will be floated and towed to the sinking site.

The divided elements 16a to 16e are sequentially connected from the shaft 14 side to the submarine ground 10 side, and the plurality of elements 16a, 16b on the tip side
is backfilled in a state where it is located on a sloped part 20 that has been excavated and formed in the seabed ground 10 in advance, and the seabed ground 1
Penetrated into 0.

In addition, a plurality of elements 16c on the shaft 14 side
16e is supported by a plurality of piles 22, 22 driven into the seabed ground 10, and is stabilized by embankment 24 around its outer periphery.

Furthermore, the foremost element 16a of the immersed tunnel 16 that has penetrated into the seabed ground 10 is provided with a protruding port 28 for carrying in a shield excavator 26 for excavating the tunnel 18. It is submerged with the loading port 28 positioned above the seabed ground 10.

When construction of the immersed tunnel 16 is completed, as shown in FIG. 1c, hollow cylinders 30 are successively connected above the loading port 28 to form a temporary loading tube 32 extending to the sea surface.

Then, when the carry-in tube 32 and the element 16a are communicated with each other, the shield excavator 26 that has been transported to the submergence site is suspended and installed inside the element 16a by the crane ship 34.

When the shield tunneling machine 26 is housed in the element 16a, the carry-in tube 32 and the carry-in port 28 are removed, and the opening of the element 16a is closed.

Figure 2 shows the state in which the shield tunneling machine has been installed.

In this embodiment, an enlarged portion is formed at the distal end of the element 16a, and the distal end surface is closed with a removable temporary wall 36. A shield tunneling machine 26 is installed within the enlarged portion, and a reaction force receiving structure 38 is provided at the rear end.

And, in the front inclined part 20 of the temporary wall 36,
Launch protection section 40 with ground improvement as necessary
is formed.

When the installation of the shield excavator 26 is completed as described above, the shaft 14 and the rear end of the immersed tunnel 16 are communicated, and the necessary equipment is transferred to the immersed tunnel 1.
6, the shield machine 26 removes the temporary wall 28, and is then launched toward the submarine ground 10.

In addition, when starting the shield machine 26, the submarine ground 10 in front of the most advanced element 16a is
As described above, if the ground is improved to form the launch protection part 40, the launch can be easily started, but if the penetration length of the tip of the immersed tunnel 16 into the submarine ground 10 is increased, the ground can be improved. is not necessarily required.

Now, according to the method for launching a shield excavator in the submarine tunnel construction method performed as described above, the shield excavator 26 that is launched directly toward the submarine ground 10 is connected to the element 16a at the tip of the submerged tunnel 16. Since this is carried out via a temporary loading pipe 32 that extends to the sea surface, each element 16a to
16e will be easier to tow and sink.

In addition, the immersed tunnel 16 of the shield launcher 26
Since the installation is carried out at the site where the immersed tunnel 16 is being immersed, these above-ground fabrications can be carried out separately and the construction period can be shortened.

<<Effects of the Invention>> As explained in detail in the embodiments above, according to the method for starting a shield tunneling machine in an undersea tunnel construction method according to the present invention, after an immersed tunnel is sunk in an inclined state from a starting shaft, its tip portion is A temporary loading tube extending above the sea surface is installed in communication with the tunnel, and a shield excavator is suspended and installed at the tip of the immersed tunnel through this loading tube, making it easy to tow and sink each element that makes up the immersed tunnel. Not only is this easier, but the shield tunneling machine can also be started earlier.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the method of the present invention in the order of steps, and FIG. 2 is an enlarged view of the main part of FIG. 1b. 10...Undersea ground, 14...Starting shaft, 16...
...Immersed tunnel, 18... Undersea tunnel, 26...
...Shield tunneling machine, 30... Carrying tube.

Claims (1)

[Claims] 1. When excavating a tunnel on the seabed using a shield excavator, the method includes installing an immersed tunnel in an inclined state from a starting shaft toward the seabed ground, and launching the shield excavator from the tip of this immersed tunnel. After an immersed tunnel is sunk, a temporary loading tube extending above the sea surface is installed in communication with the tip of the tunnel, and the shield excavator is suspended and installed at the tip of the tunnel through the loading tube. How to launch a shield tunneling machine in a tunnel.