JPH06100080B2 - Large-section tunnel construction method and ground solidification column construction device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a method of constructing a large-section tunnel, and in particular, a large section having an elliptical cross-section such as a location where an emergency parking zone on a road is provided, or a branching / merging portion of the road. The present invention relates to a method for constructing a cross-section tunnel or a large-section tunnel whose cross-sectional shape changes by widening a road into a trumpet shape, and a ground-solidifying column construction device used in the method.

<Prior art> When constructing a large-section tunnel with an existing shield machine, there is a limit to the size of the diameter, and for example, the section where the emergency parking zone is provided, the branching / merging portion of the road, etc. has an oval shape. In the case of or when it changes into a trumpet shape, the construction is difficult, and the construction section is short, and when a large construction machine is used, the construction unit price becomes high and there is a disadvantage in terms of cost.

As an alternative technique, a pipe roof construction method shown in FIG. 6 can be mentioned. In this construction method, a pipe roof 61 is driven in the axial direction of the outer periphery of the tunnel 60 to form a tunnel outer portion, and then the earth and sand inside the outer portion are excavated to construct the tunnel 60.

<Problems to be Solved by the Invention> However, in the above pipe roof construction method, since it is necessary to construct a large space for starting and reaching for excavating the pipe roof before and after the construction section of the large-section tunnel, The construction becomes large-scale and costly. Further, since the pipe roof 61 is provided in the axial direction of the tunnel, as the extension thereof becomes longer, the pipe roof 61 receives a larger load from the ground. Therefore, it is necessary to strengthen the structure such as enlarging the cross section of the pipe roof 61 to withstand the load, which makes the construction uneconomical and complicated. Furthermore, since the adjacent pipe roofs 61 are closely connected, it is difficult to manage and the individual pipe roofs 61
Since the cross section of 61 is constant, when the tunnel cross section changes, there is a problem that the change cannot be followed.

Therefore, the present invention has been made to solve the above-mentioned problems, and the purpose thereof is to construct a normal-scale vertical shaft easily and at low cost, and to extend the construction extension of a large-section tunnel. Another object of the present invention is to provide a method for constructing a large cross-section tunnel that can economically construct a tunnel outer portion having sufficient strength to withstand a load.

Another object of the present invention is to provide a method for constructing a large-section tunnel that can easily construct an outer shell that covers the entire tunnel by following changes in the tunnel section.

<Means for Solving the Problems> The present invention has been made in view of the above objects, and the gist thereof is a step of arranging advanced work shafts on both sides of a tunnel along a planned tunnel, and the parallel arranging. One of the working mines was used as a transmission base toward the other mining, and a plurality of curved steel members were installed at a predetermined interval through a predetermined tunnel above or below the planned tunnel. Along the curved steel member, the step of digging and reaching the ground improvement material injection pipe from one of the work wells to the other work well, and the reached ground improvement material injection pipe along the curved steel member. While retreating, the ground improvement material is jetted laterally from its tip to mix it with the soil particles of the ground, and the plurality of curved steel receiving members having a predetermined effective diameter are used as core materials or reinforcing materials. By creating solidification pillars of There is a method for constructing a large cross-section tunnel, which includes a step of forming a tunnel outer portion covering the entire area above and below the flannel and a step of excavating earth and sand inside the tunnel outer portion.

Here, the advanced work pits installed side by side on both sides of the tunnel are
For example, vertical shafts will be provided on both flanks of the planned tunnel, and they will be installed by the propulsion method or the shield method as a starting and reaching base. In this case, it is desirable that the size of the work pit be, for example, about 3 m in consideration of the workability of the installation work of the curved steel member and the construction work of the ground solidification column by the ground improvement material column inlet pipe. Further, the installation work of the curved steel member, for example, the curved steel pipe, can be performed by a known small-diameter steel pipe propulsion construction method or the like which enables curved construction. The size of the curved steel member is preferably, for example, 100 mm to 150 mm in diameter in consideration of its workability and strength as a reinforcing material of the ground-solidified column.

Further, the excavation of the ground improvement material injection pipe and the formation of the ground solidification column are performed by the guide member penetrating through the center, that is, the rotary sliding part that advances and retracts along the curved steel member, and the start of the rotary sliding part. A ground solidification column building device, which is continuously connected to a vertical shaft and includes a curved pipe member and a sheath pipe that forms a double pipe together with the curved steel member, wherein the rotary sliding portion cuts the ground. In order to do so, cutting means mounted on the front surface thereof, rotation driving means for rotating the rotary sliding portion around the curved steel member as an axis, high pressure fluid ejecting means for ejecting high pressure fluid during excavation, and ground solidification column A ground improvement material injection means for injecting a ground improvement material at the time of construction, while the sheath pipe is a power supply facility for supplying power such as hydraulic pressure, pneumatic pressure, and electric power to the rotary sliding portion, Supplying high-pressure fluid such as high-pressure water to the high-pressure fluid injection means It can be performed using order and the high-pressure fluid supply pipe, a soil solidifying column reclamation device comprising a ground improvement supply pipe for supplying grout cement milk or the like into the soil improvement material ejecting means. The size of the rotary sliding portion and the sheath pipe is preferably 150 mm to 200 mm, for example, in consideration of the size of the curved steel member and the space for installing the various pipes.

<Operation> In the present invention, first, the vertical shafts provided on both flanks of the planned tunnel are used as starting bases, and two advanced tunnels as working shafts having a diameter of, for example, about 3 m are used as a shield construction method and a propulsion construction method. Build along the both sides of the tunnel.
Next, a plurality of curved steel members, for example, curved steel pipes are installed at a predetermined interval from one of the two advanced tunnels to the other at a substantially right angle to the tunnel axis direction,
This is used as a guide member. Further, along the guide member, the soil-solidifying column building device is made to reach from one of the advanced tunnels to the other advanced tunnel, and then the ground-solidifying column building device is retracted and the ground improvement material is rotated and jetted laterally. , Mix and stir with the soil particles of the surrounding ground to create a solidified ground pillar. Here, the curved steel pipe is embedded in the ground solidification column as a reinforcing material. The ground-solidifying column thus provided has a short construction extension because it is formed at right angles to the axial direction of the tunnel, and can easily follow changes in the tunnel cross section due to changes in curvature and direction.

Further, the ground solidification column building device used in the method for constructing a large cross-section tunnel of the present invention, at the time of its digging, rotates the rotary sliding portion at the tip to cut the ground by the cutting means provided on the front surface thereof, and It moves forward by propulsive force from the advanced tunnel as the starting base through the sheath pipe. At this time,
High-pressure water as high-pressure fluid injected from the tip of the rotary sliding portion assists the above-mentioned cutting, fluidizes the cutting earth and sand, and discharges it through the gap between the guide member and the sheath pipe. Further, at the time of soil solidification column construction, the soil solidification column construction device is pulled back along the guide member via the sheath pipe, and in parallel with this, the soil improvement material is injected while rotating the rotary sliding portion. Is mixed with soil particles in the ground and stirred to form a solidified ground column having a predetermined effective diameter.

<Example> Next, the example of the present invention is described in detail based on an accompanying drawing.

In FIG. 1, the method for constructing a large-section tunnel of the present invention is used for constructing a confluence portion 10 of a main tunnel 11 and a branch tunnel 12 of a road having vertically arranged reciprocating lanes. That is, an outer shell portion 14 that covers the outer circumference of the tunnel is formed by a large number of ground-solidifying columns 13 formed by the method for constructing a large-section tunnel of the present invention, and then the earth and sand inside the outer shell portion 14 are excavated and removed to form a predetermined structure. Build things. As shown in FIG. 2, the outer shell 14 covering the top and bottom of the tunnel with the soil-solidifying column 13 is composed of an advanced work tunnel 15 and a soil-solidifying column 13 as a work pit for constructing the soil-solidifying column. For example, the width is 15 to 30 m and the height is 10 to 20 m. Here, since the ground solidification column 13 is formed at a substantially right angle to the tunnel axis direction, its construction extension is short, and each ground solidification column 13 is a core material, that is, a reinforcing material, for example, a curve with a diameter of about 100 mm to 150 mm. Since it has a curved steel pipe 16 as a member made of steel-shaped steel inside and has a curved shape that is convex outward, it has sufficient strength against an external load such as earth pressure. Further, by changing the curvature and the direction of the curved steel pipe 16, it is possible to easily follow the change of the tunnel cross section.

Next, a method of constructing the tunnel outer portion 14 in the method of constructing a large cross section tunnel of the present invention will be described. Prior to the construction of the tunnel outer portion 14, as shown in FIG.
At both flanks of the main line tunnel 11 near the starting point, a starting shaft 17 is constructed to excavate the advanced work tunnel 15. Advanced working tunnel with diameter 15
To build. These start shafts 17 and tunnels for advanced work
No. 15 is constructed according to the usual shield construction method and propulsion construction method.

Subsequently, the ground-solidifying column 13 is formed according to the order shown in FIGS. That is, first, FIG.
As shown in, the curved steel pipe 16 is connected to one of the advanced working tunnels.
Propel from 15a and reach the other advanced work tunnel 15b. Next, the curved steel pipe 16 is used as a guide member to propel the ground-solidifying column forming device 20 from the one advanced work tunnel 15a and reach the other advanced work tunnel 15b, as shown in FIG. 3B. Let Further, as shown in FIG. 3C, the ground solidification column forming device 20 reaching the other advanced work tunnel 15b is installed in the one advanced work tunnel.
It is pulled back toward 15a, and at the same time, the ground solidification column building device 2
The grout 40 such as cement milk is rotationally jetted as a ground improvement material from the tip of 0 toward the side of these, and this is mixed with the soil particles of the ground around the ground solidification column forming device 20 and stirred, A solidification column 13 having an effective diameter of is formed.

Such a ground solidification column 13 is continuously and densely formed in the tunnel axial direction along a large number of curved steel pipes 16 installed at predetermined intervals to form an outer shell portion 14 that covers the tunnel.

As shown in FIGS. 4 and 5, the ground solidification column forming device 20 used in the present invention is composed of a rotary sliding part 21 and a sheath pipe 22 connected to the rotary sliding part 21. The rotary sliding part 21 has an outer shell 26.
And a drilling bit 23 as a cutting means provided on the front surface thereof.
A central opening 24, a hydraulic motor 25 provided on the outer circumference of the central opening 24 in the outer shell 26, a high-pressure water jet device 27 opening at four locations on the front surface of the outer shell 26, and four openings on the outer circumferential surface of the outer shell 26. A ground improvement material injection device (28) is provided. Central opening
A curved steel pipe 16 as the guide pipe penetrates through the center of the guide pipe 24, and the ground solidification column forming device 20 moves along the guide pipe 24. Rotate. The sheath pipe 22 has substantially the same diameter as the rotary sliding portion 21, for example, a diameter of 150 mm to 200 mm, is continuously provided behind the rotary sliding portion 21 in the excavation direction, and is successively added in the advanced working tunnel 15a. . See also pipe 22
Includes a curved steel pipe 16 to form a double pipe,
In the meantime, a hydraulic hose 29 as a power supply facility for supplying or discharging driving oil for the hydraulic motor 25, and a high pressure water supply hose as a high pressure fluid supply pipe for supplying high pressure water to the high pressure water injection device 27. 30 and a grout hose 31 as a ground improvement material supply pipe for pumping the grout to the ground improvement material injection device 28.

The soil-solidified column forming device 20 having the above-described structure operates as follows during excavation and formation of the soil-solidified column. That is, at the time of excavation, the rotary sliding portion 21 is rotated to cut the earth and sand on the front surface and to move forward by the propulsive force transmitted from the advanced work tunnel 15a via the sheath pipe 22. At this time,
The high-pressure water injected from the high-pressure water injection device 27 is used for the drilling bit 23.
To excavate and fluidize the cutting earth and sand, and discharge the cutting earth and sand through the central opening 24 and the gap between the curved steel pipe 16 and the sheath pipe 22. On the other hand, at the time of ground solidification column construction, high pressure jetting of grout from the ground improvement material injection device 28 while pulling back the rotary sliding part 21 via the sheath pipe 22, and the surrounding ground is cut by this injection force and at the same time soil particles and grout. And are mixed and stirred to form a solidified ground column having a predetermined effective diameter. At this time, the generated slime is discharged through the central opening 24 and the gap between the curved steel pipe 11 and the sheath pipe 22 as in the case of the cutting soil.

<Effects of the Invention> In the method for constructing a large cross-section tunnel of the present invention, a plurality of curved ground solidification columns are formed substantially at right angles to the axial direction of the tunnel by using the advanced tunnel provided along both sides of the planned tunnel as a work pit. Since this forms the outer shell of the tunnel, a large cross-section tunnel can be constructed easily and at low cost without requiring a large working space, and even if the extension of the tunnel is long, sufficient strength to withstand the load is provided. It is possible to economically construct the tunnel outer portion having.

Further, by changing the curvature and the direction of the curved ground solidification column, it is possible to easily follow the change of the tunnel cross section in the tunnel outer portion.

Further, since the ground solidification column forming apparatus used in the present invention is constituted by the rotary sliding portion that moves using the curved steel member as the guide member and the sheath pipe connected to this, the curved solidification column is formed. Can be easily created.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an outline of a method of constructing a large-section tunnel of the present invention, FIG. 2 is a sectional view taken along line II-II of FIG. 1,
3 (a) to 3 (c) are explanatory views showing a method for forming a ground solidifying column of the present invention, FIG. 4 is a fracture cross-sectional view showing a configuration of a ground solidifying column forming device used in the present invention, and FIG. Line V- in FIG.
FIG. 6 is a sectional view taken along line V, and FIG. 6 is a sectional view showing a method of constructing a conventional large-section tunnel. 10 …… Confluence part, 13 …… Solid solidification column, 14 …… Outer part, 15,1
5a, 15b …… Advanced work tunnel, 16 …… Curved steel pipe, 17…
… Starting shaft, 20 …… Solid solidification column building device, 21 …… Rotary sliding part, 22 …… Saya pipe, 23 …… Excavation bit, 25 …… Hydraulic motor, 27 …… High pressure water injection device, 28 …… Ground improvement material injection device, 29 …… hydraulic hose, 30 …… high pressure water supply hose, 31…
... Grout horse, 40 ... Grout.

Claims (2)

[Claims] 1. A step of arranging advanced work shafts along both sides of a planned tunnel, and a plurality of curved steel members reaching from one of the work shafts as a starting base to the other work shaft. The step of installing at a predetermined interval, the step of reaching the ground improvement material injection pipe from one of the work holes to the other work hole along the curved steel member, and the reached ground improvement material injection pipe By retreating along the curved steel member and injecting a ground improvement material from its tip to mix it with natural earth and sand, a predetermined effective diameter with the curved steel member as a core material is obtained. A method for constructing a large cross-section tunnel, which comprises the steps of forming a solidified ground column and forming an outer shell of the tunnel by using it, and then excavating earth and sand inside the outer shell. 2. A rotary sliding portion which advances and retracts along a guide member penetrating through the center thereof, and a sheath pipe which includes the guide member and is connected to the rotary sliding portion. The cutting means for cutting the ground, the rotation driving means for rotating the guide member around the guide member as an axis, the high-pressure fluid injection means for injecting high-pressure fluid to the digging destination at the time of excavation, and the ground solidification column formation time. A ground improvement material injection means for injecting a ground improvement material around the guide member, and power supply equipment for the rotary sliding portion and high pressure fluid for the high pressure fluid injection means in the sheath pipe. A solidification column forming device for use in a method of lining a large cross-section tunnel, comprising a supply pipe and a ground improvement material supply pipe to the ground improvement material injection means.