JP4341998B2 - Shield machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a shield machine.
[0002]
[Prior art]
In islands and desert areas where there is little rainfall, seawater desalination plants have been constructed near the coast to secure drinking water. In addition, seawater is, for example, raw processing water for a salt production plant. In this type of seawater treatment facility, it is necessary to introduce seawater into an apparatus for desalinating seawater.
[0003]
Therefore, in such seawater treatment facilities, conventionally, seawater is taken in by a non-woven fabric wrapped around a vinyl chloride pipe penetrating a large number of water intake holes or by a water intake tunnel in which a perforated fume pipe is embedded.
[0004]
However, since the intake tunnel having such a configuration is embedded by the open-cut method or the submerged method, there are many restrictions on the construction due to the exclusive use of the area directly above the embedded position for the burying operation.
[0005]
Therefore, the present inventors have developed a technique for constructing this type of water intake tunnel by a shield method, and proposed 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 the main body plate 1 such as a steel segment or a ductile segment conventionally used in a normal shield method. It is a thing.
[0006]
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 positively taken into the interior from water intake holes (not shown) provided in the main body plate 1.
[0007]
However, when such a water intake segment 3 is used to construct a water intake tunnel by a shield machine, there are technical problems described below.
[0008]
[Problems to be solved by the invention]
In other words, in the normal shield method, the tail void generated from the difference in the outer diameter of the shield machine main body 4 and the segment is backfilled to suppress the settlement of the ground surface, thereby ensuring the early stability of the segment.
[0009]
However, when backfilling is performed in the construction of the intake tunnel, an impermeable layer 5 is formed around the permeable member 2 on the outer surface of the intake segment 3 as shown in FIG. Since it cannot be taken in, backfilling cannot be performed.
[0010]
If backfill injection cannot be performed, the shield machine and ground subsidence just above the segment will increase, and it will be difficult to ensure the early stability of the segment.
[0011]
In addition, when excavating a curved section, not only when constructing the intake tunnel described above, but also when constructing a general tunnel, the side of the shield machine is dug in advance so that the passing position of the shield machine Is weakened so that there is less competition with natural mountains.
[0012]
However, in the case of a loose sand layer or the like, if the ground improvement is not performed, there is a problem that the excavation part collapses and the competition between the shield machine and the natural ground in the curved part cannot be made sufficiently small.
[0013]
The present invention has been made in view of such problems, and the object of the present invention is to ensure the early stability of the segment while suppressing an increase in the settlement of the ground surface, and in curve construction. The object is to provide a shield machine capable of eliminating ground improvement.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a shield machine having a chamber filled with excavated earth and sand on the tip side of the shield machine body, wherein the shield machine has a water intake segment assembled on the rear side, It is for construction of a water intake tunnel capable of taking water inside, and with the excavation of the shield machine main body, the excavated earth and sand are sequentially taken into the chamber, and part of the excavated earth and sand from the chamber, Due to the digging force of the shield machine main body, a plurality of discharge passages are provided on the rear side outside of the shield machine main body and between the outer periphery of the shield machine machine and the excavation ground as it is . .
According to the shield machine configured as described above, the shield machine is for constructing a water intake tunnel in which a water intake segment is assembled on the rear side, and the excavated soil is sequentially taken into the chamber as the shield machine main body is dug. In accordance with the excavation of the shield machine main body, a part of the excavated earth and sand from the inside of the chamber is located outside the rear side of the shield machine main body, and is directly between the outer periphery of the machine and the excavated ground. Since there are multiple discharge passages to discharge, the excavated earth and sand discharged from the discharge passages are sequentially pushed backward along the outer surface of the shield machine main body, resulting from the difference in outer diameter between the shield machine and the segment Fill the tail void.
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 of the shield machine and the segment and to ensure the early stability of the segment.
In addition, during curve construction, the overexcavated portion is filled with excavated earth and sand discharged from the discharge passage, so that the collapse of the overexcavated portion of the ground can be prevented, and the excavated earth and sand can be prevented by a shield machine. Since it is excavated, it is weakened and the competition with the natural ground is also reduced.
The discharge passage may be provided with an opening / closing lid that opens at one end to a partition wall that separates the chamber and opens at the other end to a side surface of the shield machine main body and adjusts opening / closing of the discharge passage.
According to this configuration, since the discharge of excavated earth and sand from the discharge passage can be adjusted by the open / close lid, for example, in the construction of the intake tunnel, in a section where backfilling can be performed, the shield method as usual Construction becomes possible.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. 1 and 2 show an embodiment of a shield machine according to the present invention.
[0016]
The shield machine 10 shown in the figure exemplifies a case where the present invention is applied when constructing a water intake tunnel, and the water intake tunnel assembles the water intake segment 3 shown in FIGS. 3 and 4 into a cylindrical shape. It is constructed by.
[0017]
The water intake segment 3 is formed by attaching the water permeable member 2 to the outside of the main body plate 1 such as a steel segment or a ductile segment used in a normal shield method.
[0018]
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 into the inside through water intake holes provided in the main body plate 1 .
[0019]
The shield machine 10 shown in the figure is of earth pressure type, and a partition wall 16 is provided on the tip side of the shield machine main body 14 formed in a cylindrical shape.
[0020]
The chamber 18 defined by the partition wall 16 and having an open end is filled with excavated mud and used to counter the earth pressure and water pressure of the natural ground. A rotating shaft 22 that supports the cross-shaped spoke 20 is rotatably supported on the central axis of the partition wall 16.
[0021]
An unillustrated bit is fixed to the spoke 20, and the rotary shaft 22 is rotationally driven, whereby the earth and sand are excavated by the bit provided in the spoke 20 and taken into the chamber 18.
[0022]
For example, air bubbles can be used as the additive in the excavation mud taken into the chamber 18. When the air bubbles are mixed into the mud, the fluidity of the mud increases, and the soil becomes equivalent to the natural ground due to the disappearance of the air bubbles. Sex is restored.
[0023]
The basic configuration of the earth pressure type shield machine as described above is the same as that of a conventional type of device, but the shield machine 10 of the present embodiment has a significant difference in the points described below. .
[0024]
That is, the shield machine 10 of the present embodiment is provided with a plurality of discharge passages 24 for discharging a part of the drill mud from the chamber 18 to the rear side of the shield machine main body 14 as the drill mud is taken in. ing.
[0025]
One end side of each discharge passage 24 opens to the partition wall 16 that defines the chamber 18, and the other end side opens to the side surface on the rear side of the shield machine main body 14. The discharge passage 24 shown in FIG. 1 is made of, for example, a metal pipe, and shows one side of the shield machine main body 14, but a similar discharge passage 24 is also provided on the back side of this side. Is provided.
[0026]
In FIG. 1, the discharge passage 24 is illustrated as being provided in parallel in three rows on the side surface side of the shield machine main body 14, but the discharge passage 24 is provided on the upper and lower sides of the excavator body 14. Of course, it can also be provided.
[0027]
Now, according to the shield machine 10 configured as described above, the discharge passage 24 that discharges to the rear side of the shield machine main body 14 when the chamber 18 is filled as the excavation mud is taken in. Since it is provided, part of the excavation mud is discharged to the outer surface side of the rear portion of the excavator main body 14 through the discharge passage 24.
[0028]
The excavation mud discharged to the side of the excavator main body 14 is pushed by the excavation mud sequentially discharged along with the excavation of the shield excavator 10, and sequentially pushed backward along the side of the shield excavator main body 14. The tail void resulting from the difference in outer diameter between the shield machine 10 and the segment 3 is filled.
[0029]
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 ground surface settlement immediately above the shield machine 10 and the segment 3, and to ensure the early stability of the segment 3. .
[0030]
In addition, since the overexcavated portion is filled with the excavated mud discharged from the discharge passage 24 at the time of curve construction, the collapse of the overexcavated portion can be prevented, and the excavated mud can be used as a shield machine. Since it is excavated by No. 10, it is weakened and the competition with the natural ground is also reduced.
[0031]
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 can be provided in a portion opened to the partition wall 16.
[0032]
If such an opening / closing lid is provided, the discharge of the excavated mud from the discharge passage 24 can be adjusted as necessary by the opening / closing lid, so that, for example, construction of backfill injection is possible in the construction of a water intake tunnel. In the section, construction of the shield method as usual is possible.
[0033]
In the above embodiment, the case where the shield machine of the present invention is applied to the construction of a water tunnel is illustrated, but the implementation of the present invention is not limited to this, and a normal tunnel is constructed by a shield construction method. Can also be used.
[0034]
When the present invention is applied to a normal shield method, in addition to the effects described in the above embodiment, if a part of excavated earth and sand is discharged to the rear side of the shield machine main body, the friction cutting effect during excavation is improved. By supplementing the filling (reducing volume) and improving the transmission effect of the face pressure, the effect of suppressing ground subsidence can be obtained by reducing the release of ground stress at the tail.
[0035]
【The invention's effect】
As described above in detail in the embodiment, according to the shield machine according to the present invention, while suppressing the increase in settlement of the ground surface, the early stability of the water intake segment is ensured, and the ground improvement in the curve construction is achieved. Can be eliminated.
[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 the cross-sectional view taken along the 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.
4 is a cross-sectional view taken along line AA in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Main body plate 2 Permeable member 3 Water intake segment 10 Shield engraver 12 Water intake tunnel 14 Shield engraver main body 16 Bulkhead 18 Chamber 20 Spoke 24 Discharge passage

Claims (2)

In the shield machine with a chamber filled with excavated soil on the tip side of the shield machine body,
The shield machine is for the construction of a water intake tunnel in which a water intake segment is assembled on the rear side, and water can be taken inside.
With the excavation of the shield machine main body, the excavated earth and sand are sequentially taken into the chamber, and a part of the excavated earth and sand is extracted from the chamber by the excavation force of the shield machine main body. A shield machine having a plurality of discharge passages that are discharged as they are on the outer side of the rear part and between the outer periphery of the shield machine main body and the excavation ground .   The discharge passage is provided with an opening / closing lid that opens at one end of a partition partitioning the chamber and opens at the other end at a side surface of the shield machine main body, and adjusts opening / closing of the discharge passage. The shield machine according to claim 1.

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