JP2779680B2 - Construction method of underwater tunnel and underwater excavator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a technique for constructing an open shield tunnel having excellent workability.

<Conventional technology> The method of constructing the underwater tunnel is a shield method using a shield excavator or a sinking method in which a part of a land-based tunnel (tunnel element) is gradually extended while sinking in a tunnel trench. Etc. are known.

<Problems to be solved by the present invention> The above-described conventional construction techniques have the following problems.

<B> In the shield method, the length of the tunnel is lengthened by taking the earth covering 1.5 times or more the diameter of the tunnel.

If the overburden is smaller than this, there arises a problem that the tunnel floats up, and a bending stress occurs in the segment due to unbalance of earth pressure, which causes a problem in the segment structure.

<B> In the case of the burial method, a large amount of earth and sand is handled by dredging trenches and refilling after subsidence.

As a result, the problem of the landfill site and the problem of seawater pollution occur.

In addition, a dog yard is required to manufacture the box, and the submergence method has a problem that it often becomes an obstacle to the navigating ship due to the large amount of work at sea.

<Object of the present invention> The present invention has been made in order to solve the above problems, and the purpose thereof is to use a simple improved underwater excavator to provide excellent workability, It is an object of the present invention to provide an underwater tunnel construction technique capable of greatly shortening a period.

<Means for Solving the Problems> That is, the present invention relates to a method of constructing a tunnel near the water bottom, using an underwater excavator having an openable and closable entrance for carrying a ring piece, which is a constituent material of a tunnel, using an existing tunnel. After closing the tip opening with a removable water blocking wall, a ring piece is hung from above the water into the underwater excavator, the entrance of the underwater excavator is closed, the inside of the underwater excavator is drained, and the ring is submerged in the underwater excavator. An underwater tunnel construction method characterized in that an underwater tunnel is constructed while connecting pieces to the tip of an existing tunnel.

Further, the present invention relates to an excavator equipped with a shield body, a plurality of shield jacks for digging by obtaining a reaction force from an existing tunnel, and a digging means and a shaving discharge means, wherein a part of the shield body is a tunnel component. It has an opening for carrying in the ring piece, and an openable and closable gate for introducing the ring piece into the shield body while stopping water is provided outside the opening, and a digging section in the shield body is provided. An underwater excavator characterized by being equipped with a water stop wall for preventing inundation of the underwater.

<Description of the Present Invention> Hereinafter, the present invention will be described with reference to the drawings.

<A> Underwater excavator FIG. 1 shows an underwater excavator according to the present invention.

This underwater excavator is characterized in that a set piece of a tunnel is carried in from above the water and excavated while assembling the tunnel in the underwater excavator.

The underwater excavator includes a shield body 1, a plurality of shield jacks 3 that obtain a reaction force from the existing tunnel 2 to apply excavation force to the shield body 1, and excavating means and excavating and discharging means, which is a conventional shield excavating machine. It is the same as the machine.

The underwater excavator according to the present invention has an opening 4 in a part of the shield body 1, that is, an upper half of the outer shell, and is provided with a watertight gate 5 which can be opened and closed outside the opening 4.

The opening 4 is an opening for introducing the ring pieces 2a, 2b,...

Further, a bulkhead 7 is provided in the middle of the shield body 1 so as not to be flooded in the excavated portion of the underwater excavator.

In particular, the shield jack 3 penetrating the bulkhead 7
It is necessary to sufficiently prevent water from penetrating portions.

Further, the conventional underwater excavator is provided with an assembling device called an erector device for holding and assembling the segments, but the underwater excavating device according to the present invention does not include this type of assembling device.

 In FIG. 1, reference numeral 8 denotes a carry-in guide, and reference numeral 9 denotes a discharge pipe.

Reference numeral 10 denotes a detachable bulkhead attached to the tip of the existing tunnel 2, 11 soil covering over the existing tunnel 2, and 12 a water bottom.

The diameter of the bulkhead 10 is set slightly larger than the inner diameter of the existing tunnel 2 so as not to hinder the operation when the ring pieces are assembled.

<B> Watertight Gate The watertight gate 5 is opened when the ring pieces 2a, 2b,... Are carried in, and when the ring pieces 2a, 2b,.
This is a gate for the purpose of closing to prevent inundation.

A well-known gate device can be applied to the watertight gate 5, such as a configuration in which an arc plate is slidably provided by jack force.

<C> Ring Piece The conventional segment has an arc shape, but in the present invention, a ring-shaped ring piece 2a in which the tunnel is cut into a certain width,
Use 2b….

<Operation> Next, the construction method of the underwater tunnel will be described.

<B> Excavation, earth removal and earth covering (Fig. 1) In parallel with the excavation, the process of excavating by obtaining the reaction force from the existing tunnel 2 and the process of excavating the earth excavation to the shield body 1 are performed by the conventional shield excavation. It is the same as the machine.

However, due to excavation in the shallow part of the water floor, the existing tunnel 2
Is exposed, so that the soil is covered
There is a need to.

The covering soil 10 may be formed by using excavated soil or by using surrounding soil collected by a separate excavator.

It is to be noted that mortar or the like is injected into the gap at the outer periphery of the bottom or side of the existing tunnel 2.

<B> Hanging of Ring Piece (FIG. 1) The bulkhead 10 is attached to the tip of the existing tunnel 2 (end of the ring piece 2b).

Water is put in the existing tunnel 2 in advance, and the watertight gate 5 of the shield body 1 is opened.

When the watertight gate 5 is opened, water enters into the shield main body 1 through the opening 4, but the inundation range is only between the two bulkheads 7 and 10. There is no.

In this state, the ring piece 2c manufactured on land or on the water is completely suspended in the shield body 1 through the opening 4, and then the suspension wire is removed.

Since the excavator of the present invention can position the ring piece 2c using a known crane or the like, the conventional elector device is unnecessary.

Further, the water pressure acting on the front surface (cutter surface) of the shield main body 1 tends to retreat the shield main body 1 to the start side of the existing tunnel 2.

However, the pore water sealed between the bulkheads 7 and 10 prevents the shield body 1 from retreating against the force acting on the front surface.

Next, the ring piece 2c suspended using the shield jack 3 is attached to the ring piece at the tip of the existing tunnel 2.
Press on 2b.

<C> Drainage (FIG. 2) Subsequently, the watertight gate 5 is closed, and the water interposed between the two bulkheads 7 and 10 in the shield body 1 is drained.

In this drainage work, a drainage pump (not shown) is arranged on the existing tunnel 2 side or the excavation side of the shield body 1,
If the hose on the suction side of the drain pump is set to penetrate any of the bulkheads 7 and 10, the drain can be easily drained.

<D> Excavation (Fig. 3) When drainage is completed, extend the shield jack 3,
The shield body 1 is dug by one piece or several pieces while obtaining a reaction force from the existing tunnel 2.

<E> Joint construction and movement of the bulkhead (Fig. 4) The bulkhead 10 located between the ring pieces 2b and 2c at the tip of the existing tunnel 2 is removed and replaced with the tip of the ring piece 2c.

In parallel with this operation, the ring pieces 2b and 2c are tightened and connected by a PC bolt or a PC cable.

A gap between the fastening of the ring pieces 2b and 2c is filled with a filler 13 such as concrete or mortar.

Next, the watertight gate 5 is opened, the next ring piece is suspended, and a tunnel is constructed to a predetermined length while repeating the above-described steps.

<Effects of the Present Invention> The present invention has the following effects.

<B> Immediately after the ring piece suspended inside the underwater excavator is connected to the tip of the tunnel, the underwater excavator can be started, so it is excellent in workability and can greatly shorten the construction period.

<B> The structure of the watertight gate can be simplified.

<C> When the ring piece is suspended, the pore water interposed between the two bulkheads can effectively prevent the retreat of the underwater excavator against the water pressure temporarily acting on the front surface of the shield body.

[Brief description of the drawings]

FIG. 1: Sectional view of an underwater excavator FIG. 2: Sectional view of an underwater excavator for explaining a drainage process between bulkheads FIG. 3: Sectional view of an underwater excavator for explaining a excavation step Figure: Cross-section of an underwater excavator to explain the movement of the bulkhead

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int.Cl. ⁶ , DB name) E21D 9/06 331 E02D 29/063 E02D 29/073

Claims (2)

(57) [Claims] 1. A method of constructing a tunnel near the bottom of a water, comprising using an underwater excavator having an openable and closable entrance for carrying a ring piece, which is a constituent material of a tunnel, and a detachable stop at an end opening of an existing tunnel. After being closed by the water wall, the ring piece is hung from above the water into the underwater excavator, the entrance of the underwater excavator is closed, the inside of the underwater excavator is drained, and the ring piece is connected to the tip of the existing tunnel inside the underwater excavator A method of constructing an underwater tunnel, characterized by constructing an underwater tunnel while doing so. 2. An excavator having a shield body, a plurality of shield jacks for digging by obtaining a reaction force from an existing tunnel, and a digging means and a soil excavation discharging means. An opening for introducing a ring piece into the shield body while preventing water from being provided, and an excavation section in the shield body Underwater excavator, which is equipped with a water blocking wall that prevents inundation into the water.