JP2683820B2 - Subsea tunnel construction method and construction equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a submarine tunnel that does not contaminate the surrounding water area at the time of dredging of a ditch, particularly when the tunnel is constructed in a place where the soil is shallowly covered. The present invention relates to a construction method and device.

<Conventional technology> There are shield tunnels and submersion methods as construction methods for tunnels provided on the bottom of the water.

The shield construction method is a method in which a shield excavator is advanced while excavating earth and sand in front by applying a reaction force to a segment assembled in the rear and a concrete wall surface that has been placed.

With this method, if the thickness of the coated sand is sufficient, there is no effect of water pollution, but if there is no coated thickness of the sand and the trench is dug into the seabed, the excavated soil will spread to the surrounding area. Will pollute.

Further, since the excavated earth and sand is discharged to the rear through the transportation pipe, it is necessary to sequentially extend the pipe each time the shield machine advances.

On the other hand, the submersion method is a method of digging a trench on the seabed and submerging the box manufactured on land inside it.

As a result, a large work boat goes back and forth or anchors on the sea, which tends to hinder marine traffic.

In addition, when excavating and backfilling trenches, much work is done to spread the earth and sand around, which contaminates seawater.

<Purpose of the present invention> The present invention has been made for the construction of a tunnel under the above-mentioned conditions, and it is possible to excavate without contaminating the surrounding environment even when there is no covering thickness of earth and sand. It is an object of the present invention to provide a method and an apparatus capable of performing the above.

Further, it is an object of the present invention to provide a method and an apparatus that do not require complicated extension and connection work of a pipe for excavation even with the progress of excavation.

Further, it is an object of the present invention to provide a method and a device which reduce the work on the sea as compared with the submersion method and do not hinder the sea traffic.

<Configuration of the Present Invention> Next, an embodiment of the present invention will be described.

<A> Shield excavator The shield excavator 1 used in the construction method of the present invention is of a type in which earth and sand are taken into the face.

That is, the whole surface of the shield machine 1 is partially or entirely opened, and a partition wall 11 is provided on the inner side of the shield machine 1.
To form

The partition wall 11 blocks the inflow of the earth and sand taken into the earth and sand chamber 12 into the fuselage.

<B> Sediment Transport Pipe The above-mentioned structure is almost the same as that of the known shield machine, but particularly in the shield machine of the present invention, one end of the sediment transport pipe 2 is attached to a part of the sand chamber 12.

The sediment transport pipe 2 does not penetrate the inside of the shield machine 1.

Therefore, the other end of the pipe 2 is raised toward the surface of the water, the upper end of the pipe 2 is exposed above the water, and the pipe 2 can be transported to the plant 31 of the work boat 3 described later.

Furthermore, in the sediment chamber 12, parallel to the sediment transport pipe 2,
Install a muddy water recovery pipe 21.

The muddy water recovery pipe 21 is a pipe for transporting the muddy water separated in the plant 31 of the work boat 3 toward the sediment chamber 12 again.

<C> Work Vessel The work vessel 3 is floated on the water surface above the shield machine 1.

This work boat 3 is a plant 31 for separating muddy water and sediment.
Is provided.

The sediment transport pipe 2 and the muddy water recovery pipe 21 are connected to the plant 31.

Further, the work vessel 3 is provided with a loading cylinder 32 for loading the separated soil into the sea again substantially vertically downward.

<Construction Method> Next, a construction method in which the above devices are combined will be described.

<A> Excavation Similar to a known shield excavator, a reaction force is applied to the tunnel body 13 formed at the rear portion of the shield excavator 1 to obtain a forward force.

The tunnel body 13 employs known methods such as segment assembly and concrete pouring.

Then, the earth and sand are taken into the earth and sand chamber 12 by using the rotary cutter on the front part.

<B> Transport of sediment into the water The sediment taken into the sediment chamber 12 is pushed up along with the mud through the sediment transport pipe 2 toward the water.

Therefore, unlike the conventional method, it is not necessary to transport the earth and sand backward through the inside of the tunnel body 13.

Since the end of the sediment transport pipe 2 is open toward the plant 31 of the work boat 3, the transported sediment is separated into mud and muddy water.

<C> Muddy Water Recovery The muddy water is transported to the earth / sand chamber 12 of the shield machine 1 again through the muddy water recovery pipe 21 without being discarded to the outside of the work boat 3.

Therefore, muddy water having a high specific gravity can be replenished without waste.

<D> Covering with earth and sand The upper part of the tunnel body 13 constructed on the seabed is covered with earth and sand for protection.

Therefore, the earth and sand are thrown from the earth and sand input cylinder 32 of the work boat 3 toward the upper part of the tunnel body 13 constructed on the seabed and the surroundings.

<E> Others In order to protect the tunnel body 13, a method of mounting a protective block on the upper part or the periphery or injecting mortar into the periphery is the same as the conventional method.

<Effects of the Present Invention> Since the present invention is a construction method and apparatus for performing the construction as described above, the following effects can be obtained.

<B> Even under conditions where the bottom of the water does not have any thickness of earth and sand, it is possible to excavate a shield machine, construct a tunnel, and cover with earth and sand without polluting the surrounding environment.

<B> Tunnels can be constructed while excavating trenches at a depth where there is no soil cover, so the tunnel length can be shortened compared to when installing in a deep position, which is extremely economical. Is.

<C> Excavated earth and sand are transported through the face directly to the sea and processed without passing through the interior of the fuselage unlike conventional shield excavators.

Therefore, complicated extension work of the sediment discharge pipe due to the forward movement of the aircraft is unnecessary.

Inside the shield machine, a transport pipe for discharging sediment,
No other equipment is needed and a sufficient internal space can be secured.

<D> The shield machine is excavated with the upper part exposed to the seabed.

Therefore, even if something goes wrong with the machine,
Can perform repairs and other actions from the sea.

[Brief description of the drawings]

 FIG. 1: Explanatory drawing of the construction state of the present invention FIG. 2: Front view thereof

Claims (2)

(57) [Claims] 1. An excavation device having a sand chamber with an open front, a pipe for pushing up the sand in the sand chamber above the water, and an excavating device for advancing backward with a reaction force. The excavation of a ditch on the bottom of the water with virtually no overburden on the top of the tunnel, the tunnel body is constructed at the rear of the trench, and the sediment stored in the sediment chamber is collected by a work boat above the water. Method 2. The front surface is partially or wholly opened, and a partition is provided inside thereof to form a sediment chamber, and one end of a pipe for discharging the internal sediment toward water is opened to the sediment chamber. The other end of the pipe is open to the outside of the device, and it is a device for constructing a water-bottom tunnel, which moves backward with a reaction force.