JPH11159283A - Shield machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure early stability of segments while suppressing the increase of subsidence of the ground surface so as to eliminate soil improvement in curve work execution. SOLUTION: A bulkhead 16 is provided on the tip side of a shield machine body 14. A chamber 18 partitioned by the bulkhead 16 and opened on the tip side is used to fill excavated mud so as to oppose water pressure and earth pressure of the natural ground. A shield machine is provided with a plurality of discharge passages 24 for discharging part of excavated mud from the chamber 18 to the rear side of the shield machine body 14. One end side of each discharge passage 24 is opened to the bulkhead 16 for partitioning the chamber 18, and the other end side is opened to the side face of the rear side of the shield machine body 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield machine.

[0002]

2. Description of the Related Art In an island or a desert area with little rainfall, a seawater desalination plant is constructed near a coast to secure drinking water. In addition, seawater is, for example, raw water for treatment in a salt production plant, and in this type of seawater treatment facility, it is necessary to introduce seawater to a device for desalinating seawater or the like.

[0003] Therefore, in such a seawater treatment facility, seawater is conventionally taken in by a nonwoven fabric wound around a polyvinyl chloride pipe formed through a large number of water intake holes, or by an intake tunnel in which a perforated fume pipe is buried. .

However, since the intake tunnel having such a configuration is buried by the open-cutting method or the burial method, there are many restrictions on construction due to the fact that the area immediately above the burying position is exclusively used for burying work.

Therefore, the present inventors have developed a technique for constructing this kind of intake tunnel by a shield method, and proposed it in Japanese Patent Application No. 9-218492. As shown in FIGS. 3 and 4, the segments used in this construction method are integrated by attaching a water-permeable member 2 to the outside of a main body plate 1 such as a steel segment or a ductile segment conventionally used in a normal shield method. It was done.

The water permeable member 2 is made of porous concrete or the like, and has a structure in which groundwater or the like passing through the water permeable member 2 is actively taken in from a water intake hole (not shown) provided in the main body plate 1. ing.

However, when constructing an intake tunnel by using a shield excavator using such an intake segment 3, there are technical problems described below.

[0008]

That is, in the ordinary shield method, backfilling is performed on a tail void generated due to a difference in outer diameter between the shield machine 4 and the segment, thereby suppressing the settlement of the ground surface, and the early stage of the segment. Stability was ensured.

However, when backfilling is performed in the construction of the intake tunnel, as shown in FIG. 4, an impermeable layer 5 is formed around the permeable member 2 on the outer surface of the intake segment 3,
Since outside water cannot be taken in from the water intake segment 3, backfill injection cannot be performed.

[0010] If backfilling cannot be performed, the ground excavation just above the shield machine and the segment increases, and it becomes difficult to secure early stability of the segment.

In the excavation of the curved section, not only when constructing the above-mentioned intake tunnel, but also when constructing a general tunnel, the side of the shield excavator is dug in advance and the shield excavator is excavated. Has been softened so that competition with the ground is reduced.

However, if the ground improvement is not carried out in a loose sand layer, there is a problem that the excess dug portion collapses and the competition between the shield machine and the ground at the curved portion cannot be sufficiently reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to secure early segment stability while suppressing an increase in the settlement of the ground surface. An object of the present invention is to provide a shield machine capable of eliminating ground improvement in curved construction.

[0014]

In order to achieve the above object, the present invention relates to a shield excavator provided with a chamber filled with excavated sediment on the tip side of a shield excavator main body. Accordingly, a discharge passage for discharging a part of the excavated earth and sand from the chamber to the rear side of the shield machine body is provided. According to the shield excavator configured in this way, a part of the excavated sediment is discharged from the chamber to the rear side of the shield excavator body with the incorporation of excavated sediment. The discharged excavated earth and sand is sequentially pushed backward along the side surface of the shield machine and fills a tail void resulting from a difference in outer diameter between the shield machine and the segment. Therefore, without forming an impermeable layer on the outer periphery of the water intake segment, it is possible to suppress an increase in the ground excavation just above the shield excavator and the segment, and to secure early stability of the segment. In addition, at the time of curve construction, the excavated part is filled with excavated earth and sand discharged from the discharge passage, so it is possible to prevent the collapse of the excavated part of the ground and the excavated earth is shielded by a shield excavator Because it is excavated, it is weakened and competition with the ground is reduced. The discharge passage may have an opening at one end of a partition wall separating the chamber and the other end opened at a side surface of the shield machine body, and may be provided with an opening / closing lid for adjusting opening and closing of the discharge passage. According to this configuration, the discharge of the excavated earth and sand from the discharge passage can be adjusted by the opening / closing lid. Construction becomes possible. Further, the shield machine of the present invention can be suitably used for construction of an intake tunnel.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Figure 1
2 shows an embodiment of the shield machine according to the present invention.

The shield machine 10 shown in FIG. 1 illustrates a case where the present invention is applied to construct an intake tunnel. The intake tunnel is formed by connecting the intake segment 3 shown in FIGS. It is constructed by assembling.

The water intake segment 3 is formed by attaching a water permeable member 2 to the outside of a main body plate 1 such as a steel segment or a ductile segment used in a normal shield method.

The water permeable member 2 is made of porous concrete or the like, and has a structure in which groundwater or the like that has passed through the water permeable member 2 is actively taken in from a water intake hole provided in the skin plate.

The shield machine 10 shown in FIG.
Is an earth pressure type, and a partition 16 is provided at the tip end side of a shield machine body 14 formed in a cylindrical shape.

The chamber 18 defined by the partition 16 and having an open front end side is filled with excavated mud and the earth pressure of the ground is reduced.
Used to counter water pressure. A rotary shaft 22 that supports the cross-shaped spokes 20 is rotatably supported on the center axis of the partition wall 16 in a state of penetrating therethrough.

A bit (not shown) is fixedly mounted on the spoke 20, and the rotary shaft 22 is driven to rotate to excavate earth and sand with the bit provided on the spoke 20.
It is taken into the chamber 18.

For the excavated mud taken into the chamber 18, for example, air bubbles can be used as an additive, and when air bubbles are mixed into the mud, the fluidity of the mud is increased, and the soil quality equivalent to that of the ground due to disappearance of the air bubbles is increased. And the water permeability is restored.

The basic structure of the earth pressure type shield machine described above is the same as that of the conventional type of machine, but the shield machine 10 of the present embodiment has the following points.
There are notable differences.

That is, the shield machine 10 of the present embodiment
A plurality of discharge passages 24 are provided for discharging part of the excavated mud from the chamber 18 to the rear side of the shield machine body 14 as the excavated mud is taken in.

One end of each of the discharge passages 24 is connected to the chamber 1.
The shield excavator body 14 is open at the rear side surface at the other end thereof. The discharge passage 24 shown in FIG. 1 is formed of, for example, a metal pipe, and illustrates one side of the shield machine body 14, but a similar discharge passage 24 is also provided on the back of this side. Is provided.

FIG. 1 shows an example in which the discharge passage 24 is provided in three rows in parallel on the side surface of the shield machine body 14, but the discharge passage 24 is provided at the upper part of the machine body 14 Of course, it can also be provided on the lower side.

According to the shield machine 10 constructed as described above, when the chamber 18 is filled with the excavated mud, the shield machine 1
Since the discharge passage 24 is provided at the rear side of the excavator 4, part of the excavated mud passes through the discharge passage 24 and is discharged to the side surface of the machine body 14.

The excavated mud discharged to the side surface of the excavator body 14 is pushed by the excavated mud sequentially discharged along with the excavation of the shield excavator 10, and is sequentially rearward along the side surface of the shield excavator body 14. Pushed to the shield machine 10
And tail voids resulting from the difference between the outer diameters of the segments 3.

Therefore, without forming an impermeable layer on the outer periphery of the water intake segment 3, it is possible to suppress an increase in the subsidence of the ground surface immediately above the shield machine 10 and the segment 3, and to secure early stability of the segment 3. be able to.

In addition, in the case of curve construction, an extra portion is
Since the excavated mud is filled with the excavated mud discharged from the discharge passage 24, it is possible to prevent the collapse of the ground in the excavated portion, and the excavated mud is softened because it is excavated by the shield machine 10. Competition with the mountain will also be smaller.

In the discharge passage 24 of the shield machine 10 shown in the above embodiment, for example, a slide-type opening / closing lid for adjusting the opening / closing of the discharge passage 24 may be provided in a portion opened to the partition wall 16. it can.

When such an opening / closing lid is provided, the discharge passage 2
Since the discharge of excavated mud from 4 can be adjusted as required by the opening and closing lid, for example, in the construction of an intake tunnel, in the section where backfill injection can be performed, the construction of the shield method as usual Will be possible.

In the above-described embodiment, the case where the shield machine according to the present invention is applied to the construction of a water tunnel is illustrated. However, the present invention is not limited to this. It can also be used when building by construction methods.

When the present invention is applied to a normal shield method, in addition to the operation and effect described in the above embodiment, when a part of the excavated earth and sand is discharged to the rear side of the shield machine, the friction cut effect at the time of excavation is reduced. Improvement, supplementation of backfill injection (reduction of amount), and improvement of the effect of transmitting the face pressure can reduce the release of the ground stress at the tail part, thereby suppressing the land subsidence.

[0035]

As described above in detail in the embodiments,
ADVANTAGE OF THE INVENTION According to the shield machine which concerns on this invention, the early stability of an intake segment can be ensured, and the ground improvement in curve construction can be eliminated, suppressing the increase in the settlement of the ground surface.

[Brief description of the drawings]

FIG. 1 is an external view showing an embodiment of a shield machine according to the present invention.

FIG. 2 is a view showing a state where a cross-sectional view taken along a line BB of FIG. 1 is rotated by a required angle.

FIG. 3 is an external view when a water intake tunnel is constructed with a conventional shield machine.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body plate 2 Permeable member 3 Intake segment 10 Shield excavator 12 Intake tunnel 14 Shield excavator main body 16 Partition wall 18 Chamber 20 Spoke 24 Discharge passage

Claims (3)

[Claims] 1. A shield excavator provided with a chamber filled with excavated earth and sand at a tip side of a shield excavator main body, wherein a part of the excavated earth and sand is removed from the chamber with the intake of the excavated earth and sand. A shield machine wherein a discharge passage is provided at a rear side of the machine body. 2. The discharge passage has one end opened to a partition separating the chamber and the other end opened to a side surface of the shield machine, and an opening / closing lid for adjusting opening and closing of the discharge passage is provided. The shield machine according to claim 1, wherein: 3. The shield machine according to claim 1, wherein the shield machine is used for building an intake tunnel.