JPH04343995A - Middle part covering structure of juxtaposed tunnels - Google Patents

Abstract

PURPOSE:To safely construct juxtaposed tunnels by disposing a tractive member for supporting the force for extending both the tunnels and a strut member for supporting the force for pressing both the tunnels to the center in the chord direction of a circular pipe erected between both the tunnels. CONSTITUTION:Polygonal roofs 12 formed by mutually connecting a number of single straight pipes in a circular form are erected above and under juxtaposed tunnels 11, their double end parts are embedded in and fixed to fixing members 16 within the tunnels 11. A pillar 18 is constructed between the upper and lower fixing members 16. A straight roof 13 formed by mutually connecting single straight pipes linearly is interposed in the chord direction between both the end parts of the roof 12, and both its end parts are embedded and fixed to the fixing members 16. Further, a PC cable 15 is inserted through the roof 13, and stretched and fastened to the fixing members 16 through fixing blocks 17.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intermediate lining structure for an attached tunnel, and more particularly to an intermediate lining structure for an attached tunnel, which is constructed underground prior to excavation of the intermediate section.

0002

2. Description of the Related Art For example, when constructing a station in the middle of railway tunnels for up and down lines that are installed side by side, it is necessary to excavate the middle part to form a work space. The conventional construction method for creating such a space is to stabilize the ground by injecting a ground improvement agent into the middle part from both tunnels, and then excavating the inside of the tunnel while assembling segments using an arch-shaped shield machine. The so-called roof shield construction method is known, but in this construction method, the face (excavation part) is opened, so it cannot be constructed at a deep depth and in places where the groundwater level is high. On the other hand, as a construction method that builds a lining structure before excavation and seals the excavated part, it is possible to construct a hollow space even in places with poor geological conditions. A construction method has been developed in which curved steel pipes are strung together at predetermined intervals to create a lining structure.

0003

[Problems to be Solved by the Invention] However, although the conventional lining structure using curved steel pipes extending in an arc shape stably supports the load after excavation is completed, the curved steel pipes and intermediate portions No consideration was given to the unbalanced loads on the tunnels on both sides. That is, as shown in FIG. 12, the axial force N generated on the curved steel pipe 51 due to the load P applied from above due to excavation from the upper part of the sealed intermediate section 50 is reduced in both tunnels at the ends of the curved steel pipe 51. Since it does not have a structure to counter the horizontal component force A which is the force that tries to spread the tunnels 52 and the force H which tries to push both tunnels 52 toward the center, problems such as the tunnels rotating due to these unbalanced loads are caused. arise.

[0004]The present invention has been made in view of these conventional problems, and its purpose is to reduce the displacement of tunnels, etc. by stably supporting the uneven load that occurs when excavating the middle part of the tunnel. - An object of the present invention is to provide a lining structure for the middle part of an attached tunnel, which can prevent deformation and safely construct the middle part of the tunnel.

[0005]

[Means for Solving the Problems] The present invention has been made in view of the above object, and the gist thereof is to provide a cover prior to excavation of the intermediate portion in order to form a space in the intermediate portion of an attached tunnel. In the engineering structure, there is an arc-shaped pipe built across both tunnels, a traction member installed in the chord direction of the arc-shaped pipe to support the force that tries to push both tunnels apart, and a traction member that pushes both tunnels toward the center. The intermediate lining structure of the attached tunnel is equipped with struts that support the force.

[0006] The arc-shaped pipes include not only curved pipes of a predetermined length connected by welding or the like, but also so-called polygonal roofs in which straight pipes of a predetermined length are connected in an arc shape. Here, if you use a polygonal roof,
It becomes easy to manufacture pipes of each predetermined length, and the excavation mechanism at the tip can be simplified.

[0007]

[Operation] In the intermediate lining structure of the tunnel of the present invention,
The traction member installed in the chordal direction of the arcuate pipe supports the component force that tends to push both tunnels apart due to the axial force generated in the arcuate pipe. Additionally, the struts installed in the chord direction of the arc-shaped pipes support the force that tends to push both tunnels toward the center. In other words, the arc-shaped pipe, together with the traction member and strut material, forms a so-called triangular truss between both tunnels that supports the load by mutual axial force, and firmly fixes both tunnels to prevent their displacement and deformation. prevent.

[0008]

Embodiments Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, an intermediate lining structure 10 for a parallel tunnel according to the present invention has an arc-shaped structure extending over a parallel tunnel 11 at predetermined intervals, for example, about 200 mm, in the tunnel axis direction. A polygonal roof 12, a straight roof 13 as a strut member interposed in the chord direction between both ends of the polygonal roof 12, and a PC cable 15 as a traction member inserted into the straight roof 13. be done. In this embodiment, the lining structure 10 is installed above and below the parallel tunnel 11, and the gap between the polygonal roofs 12 is sealed by soil improvement to form the lining body 1 that closes the middle part of the tunnel. There is. The polygonal roof 12 is, for example, a straight pipe 14 with a diameter of 500 mm and a length of about 0.5 to 2 m.
are connected in a circular arc shape, and both ends thereof are fixed members 16 that are provided inside the tunnel 11 and integrally support the ends of the polygonal roof 12, the straight roof 13, and the PC cable 15.
It will be buried and fixed in. On the other hand, the straight roof 13 is formed by connecting the straight pipes in a straight line, and similarly, both ends thereof are buried and fixed in the fixing member 16. In addition, the PC cable 15 is
It is tension-fastened to a fixing member 16 via a fixing block 17, and is fixed within the straight roof 13 by grouting or the like. Further, a column 18 is constructed between the upper and lower fixing members 16 to mutually support the load in the vertical direction.

In order to construct a lining body using such a lining structure 10, a polygonal roof 12 is first constructed, as shown in FIG. That is, while connecting the straight pipes 14 in an arc shape, the polygonal roof 12 is propelled and installed using the propulsion jack 21 installed on the frame 20 in one tunnel 11 and the excavation device 23 provided at the tip. Here, as shown in FIG. 3, a sheath pipe 19 is attached to the launch opening base 22 of the polygonal roof 12, and a packing material 24 such as urethane foam is filled between this and the straight pipe 14 to propel the Ensures watertight properties over time. Moreover, since the ends of the straight pipes 14 are cut diagonally, as shown in FIG. 4, when a plurality of straight pipes 14 are connected, an arch-shaped roof is formed. Further, these single straight pipes 14 are connected to a chuck 26 attached to a flange 25a at the rear end of the preceding single straight pipe 14 via a flange 25 provided on the inner circumference, as shown in FIG. The connection is made by inserting a locking pin 27 attached to a flange 25b at the tip of the pipe 14. Further, as shown in FIGS. 6 and 7, inside the polygonal roof 12, after the polygonal roof 12 is installed, the polygonal roof 12 is
A chemical injection pipe 26 is provided for supplying a ground improvement agent for improving and solidifying the surrounding ground, and the chemical injection pipe 26 is arranged radially in three directions for fixing it to the polygonal roof 12. A mounting pipe 30 communicates with the injection nozzle 28 . Note that the tip opening of the injection nozzle 28 is shown in FIG.
As shown in the figure, a PVC cap 29 is attached from the outside of the polygonal roof 12, and the PVC cap 29 prevents earth and sand from flowing in from the opening during excavation, and when injecting a ground improvement agent, it prevents dirt from flowing into the ground by the injection pressure. is extruded. Furthermore, by moving a surveying sensor back and forth along the chemical injection tube 26, it is possible to accurately measure the locus of the tip of the polygonal roof 12.

After the construction of the polygonal roof 12 is completed, the straight roof 13 is constructed next. The construction of the straight roof 13 is carried out using substantially the same construction method as that for the polygonal roof 12, that is, by connecting straight pipes 14 in a straight line and constructing the frame 2 in the tunnel 11.
The straight roof 13 is propelled and installed in the chord direction of the polygonal roof 12 by a propulsion jack 21 installed at the top of the roof 12 and an excavator 23 (see FIG. 2) installed at the tip.

Furthermore, as shown in FIG. 9, fixing members 16 are constructed of concrete at the ends of the polygonal roof 12 and the straight roof 13 to bury and fix both ends together, and a PC is installed on the straight roof 13. The cable 15 is inserted and tensioned to the fixing member 16 via a fixing block 17 attached to the fixing member 16. Then, grout is injected into the straight roof 13 through which the PC cable 15 is inserted to fix the PC cable 15.

Then, by pressurizing the soil improving agent into the chemical injection pipe 26 and solidifying the area around the polygonal roof 12 (see FIGS. 6 and 7), the gap between the polygonal roofs 12 is sealed and the necessary Accordingly, the polygonal roof 12 is filled with concrete to increase its rigidity. Furthermore, as shown in FIG. 10, pillars 18 are constructed between the upper and lower fixing members 16 at predetermined intervals in the tunnel direction, and the lining body 1 (see FIG. 1) is completed.

[0014] In addition, if water cannot be stopped using only the chemical injection method during construction under high water pressure, as shown in Fig. 11, a freezing liquid may be poured into the freezing pipe 31 installed in the straight pipe 14 in advance. If frozen soil 32 is formed at the joint, water can be stopped more reliably.

[0015] In the lining body constructed as described above, the lining structures 10 are installed above and below the middle part of the tunnel.
Both tunnels are firmly fixed as a so-called triangular truss by a polygonal roof 12, a straight roof 13, and a PC cable 15.

[0016]

As described above, according to the present invention, the middle part of the parallel tunnels is covered by the arcuate pipe and the traction member and strut member provided in the chordal direction of the arcuate pipe, and both tunnels are covered. Since it is firmly fixed, the uneven load generated during excavation of the intermediate part is stably supported, thereby preventing displacement and deformation of the tunnel, etc., and therefore, the construction of the intermediate part of the tunnel can be carried out safely.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a lining body using the lining structure of the present invention.

FIG. 2 is an explanatory diagram showing the construction status of the lining structure of the present invention.

FIG. 3 is an explanatory diagram showing the details of the starting mouth part during construction of the lining structure of the present invention.

FIG. 4 is a schematic diagram showing the configuration of a polygonal roof as an arcuate pipe.

FIG. 5 is an explanatory diagram showing a connection structure of a polygonal roof.

FIG. 6 is an explanatory diagram showing a situation in which a chemical liquid injection pipe is attached inside a polygonal roof.

FIG. 7 is a sectional view taken along line II in FIG. 6, showing a situation in which a chemical liquid injection pipe is attached inside the polygonal roof.

FIG. 8 is an explanatory diagram showing a situation in which a cap is attached to a blow-off nozzle of a polygonal roof.

FIG. 9 is a front view showing the construction status of the lining structure of the present invention.

FIG. 10 is a front view showing the lining structure after construction is completed.

FIG. 11 is an explanatory diagram showing a situation in which frozen soil 32 is formed using freezing piping.

FIG. 12 is an explanatory diagram of the load generated during excavation of the intermediate portion in a conventional lining structure.

[Explanation of symbols]

10 Lining structure 11 Tunnel 12 Polygonal roof (arc-shaped pipe) 13 Straight roof (stripe beam material) 15 PC cable (traction member)

Claims (1)

[Claims] Claim 1: In order to form a space in the middle part of the annexed tunnel, in the lining structure installed before excavation of the middle part, arcuate pipes are installed in both tunnels, and arcuate pipes are installed in the chord direction of the arcuate pipes. The intermediate lining structure of the attached tunnel includes a traction member that supports the force that tries to push both tunnels apart, and a strut member that supports the force that tries to push both tunnels toward the center.