JP2898908B2 - Construction method of girder for tunnel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of constructing a girder that receives a load of tunnel lining, and more particularly to a method of constructing a girder using a girder integrated segment having a segment portion and a girder portion.

[0002]

2. Description of the Related Art In lining a so-called multi-circle tunnel having a cross-sectional shape in which a plurality of circles are connected, a wing segment corresponding to the shape is used at the intersection of adjacent circles. The wing segment is supported by the column because a large load acts on the wing segment. However, if pillars are installed for each wing segment, the usable space is limited, and thus the underground space thus formed is not suitable as a space for a subway station, an underground shopping mall, an underground parking lot, or the like.

[0003] For this reason, a girder extending in the axial direction of the tunnel is constructed, and this girder is supported by a plurality of spaced columns, the load of the wing segment is received by the girder, and the structure is transmitted from the girder to the column. A method of lining a multi-circle tunnel has been proposed to widen the underground space.

A conventional method of lining a multi-circle tunnel uses a wing segment integrally having a lining segment and a girder, and at the time of assembling, a wing segment adjacent to the tunnel in the axial direction is used. The girder part is connected with a plurality of connecting plates and a plurality of screw members while being connected by a plurality of screw members, thereby constructing a long girder in the axial direction of the tunnel.

However, in the lining constructed by the conventional method, the stiffness of the girders is extremely greater than the stiffness of the segment portions, so that the reaction force caused by the thrust for moving the shield excavator forward is directly transmitted between the segment portions. Instead, most of the thrust is concentrated on the girder. As a result, in the lining constructed by the conventional method, the gap between the neutral axis of the girder and the position where the reaction force acts (the amount of eccentricity) is large, and the axial force due to the reaction force and the eccentric bending moment are tunneled. Act simultaneously on the digits during the construction of. As described above, the axial force and the eccentric bending moment acting on the spar are much larger than the load acting on the spar when the tunnel is completed.

In a structure in which a large axial force and an eccentric bending moment act on a girder during the construction of a tunnel, the mechanical strength of the girder itself and the mechanical strength of a joint (a connecting plate, a screw member, etc.) for connecting the girder part are reduced. Not the load when the tunnel was completed,
It must be determined by the thrust at the time of tunnel construction, and the girders and joints are unnecessarily large, which is uneconomical. In addition, since the size of the girder and the joints are limited by their assemblability, construction limitations, etc., when the thrust and the amount of eccentricity increase, it is not possible to cope only by increasing the cross section of the girder and the joints. The structure cannot be established.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the need to determine the mechanical strength of a girder and its joint by the thrust at the time of tunnel construction.

[0008]

A method for constructing a tunnel girder according to the present invention is directed to a method for constructing a tunnel girder integrated with a girder integrated segment having a lining segment and a girder receiving a load acting on the segment. The excavator is sequentially arranged in the axial direction of the tunnel along with the excavation, and the segment portions of the girder integrated segments adjacent in the axial direction of the tunnel are connected by a plurality of first screw members. The method includes connecting the girder portion with a plurality of connecting plates attached to one of the girder portions and a plurality of second screw members. When assembling the segments, each of the first screw members is tightened, and Loosely tightened, and the loosely tightened second screw member is moved forward by a plurality of integrated spar segments connected by the loosely tightened second screw member. After the integrated segment is disposed,
It is characterized by being strongly tightened.

When a reaction force acts on the girder integrated segment while the second screw member is loosely tightened, the reaction force directly transmitted between the girder portions adjacent in the axial direction of the tunnel is loosely tightened. Hardly because of the two screw members,
Most of the reaction force is transmitted directly between the segments.

Each connecting plate is attached to one of the girder portions to be connected to each other, so that each connecting plate is subjected to a reaction force caused by the rotation of the cutter of the excavator and a load in a tunnel transverse direction generated at the time of excavating a curved portion. It acts to prevent displacement of the segments.

Since the reaction force acting on the segment during excavation is absorbed by the ground around the segment, the reaction force acting on the segment on the rear side is smaller. For this reason, the loosely tightened second screw member is strongly tightened after the plurality of girder integrated segments are arranged in front of the girder integrated segments connected by the second screw member.

According to the present invention, when assembling the segments,
Since the first screw member is tightened and the second screw member is loosely tightened, it is not necessary to consider the effect of reaction force caused by thrust in the design of the girder, and the mechanical strength of the girder portion and its joint is reduced. It does not need to be determined by the thrust at the time of tunnel construction.

As described above, if it is not necessary to consider the effect of the reaction force caused by the thrust in the design of the girder, it is possible to design the girder rationally and economically. The attendant advantages of being able to reduce dimensions, good workability of their assembly, great freedom of their design, unrestricted placement of jacks, and advantageous for directional control of shielded excavators Is generated.

In a preferred embodiment, the spar-integral segment corresponding to the loosely tightened second screw member is supported by a temporary column including a screw jack until the second screw member is strongly tightened. The permanent pillar may be provided instead of one temporary pillar, or may be assembled after removing the temporary pillar.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 to 5, in the following example, the case where the spar integrated segment 10 is used as a wing segment corresponding to the upper intersection of adjacent circles will be described. It may be used as a wing segment corresponding to the lower intersection.

The spar-integrated segment 10 includes a segment portion 12 acting as a tunnel lining and a segment portion 12.
Girder part 1 assembled as a girder that receives a load acting on it
And 4 integrally.

The segment portion 12 includes an elongated outer plate 16 bent in accordance with the shape of the tunnel portion to be arranged, and three first rib plates 18 integrally attached to the outer plate 16 by welding or the like. , 20, 22 and a plurality of vertical second rib plates 24 integrally attached to the adjacent first rib plates 18, 20, 22 by welding or the like,
And a plurality of horizontal third rib plates 26 integrally attached to the rib plates 18, 20, 22 by welding or the like.

The first rib plates 18, 20 and 22 are respectively assembled to one edge, the center and the other edge of the outer plate 16 in the width direction (axial direction of the tunnel) so as to be orthogonal to the axis of the tunnel. ing. The plurality of second rib plates 24 spaced apart in the width direction of the spar-integrated segment 10 have holes 28 for inserting an operator's hand or tool into the space between the rib plates 24 when connecting the segments. (Fig. 3
reference).

The girder portion 14 is formed of a steel material having a rectangular cross-sectional shape, and has first rib plates 18, 20,.
22. The girder portion 14 is provided with the first, second and third rib plates 18, 20, 22, 24,
26 is fixed by welding or the like. The length of the girder 14 is slightly smaller than the width of the segment 12.

At one end of the beam portion 14, a plurality of pairs of connecting plates 3 are provided.
0 is attached. The connecting plates 30 of each pair are
4 is fixed to the rear end of the girder portion 14 by bolts and nuts or by welding so as to sandwich one end edge of the fourth rib 4, and penetrates the first rib plate 18 on the rear side to the rear of the first rib plate 18. extend.

The protrusion or extension of the connecting plate 30 extends rearward through a notch 32 formed in the first rib plate 18. The notch 32 is formed around the girder 14. Although not shown, a plurality of notches corresponding to the notches 32 are also formed in the first rib plate 22 on the front side (face side). Each notch of the first rib plate 22 is sized to receive an extension of a connecting plate of an adjacent spar-integrated segment to connect the spar of an adjacent spar-integrated segment.

As shown in FIG. 1 and FIG.
Has a lower end with an extension 36 projecting downward from the other spar-integrated segments 10. The lower end of the extension 36 is received on the upper end of the main pillar 34. The main columns 34 are arranged at intervals of several meters, preferably 4 m.
It is installed at intervals of up to 6 m.

At the time of assembling, the girder integrated segment 10 is provided with the first rib plate 1 at the intersection of adjacent circles with the excavation of the multicircular tunnel by the multicircular shield type tunnel excavator.
8 is arranged on the existing segment ring so that the extension portion of the connecting plate 30 passes through the cutout portion of the first rib plate 22 of the existing beam integral segment, and the screw jack portion. Are supported by the temporary pillar 38 having The girder integrated segment 10 having the extension 36 is supported by the main pillar 34 instead of the temporary pillar.

Next, the segment portion 12 of the integrated girder segment 10 is connected to the segment portion of the existing girder integrated segment by a plurality of first screw members using bolts and nuts. A plurality of second screw members using nuts are connected to the beam portion 14 of the existing beam integrated segment. The second screw member that connects the extension of the connection plate 30 to the adjacent girder is loosely tightened to the extent that it slides against the thrust of the shielded tunnel excavator. For this reason, these second screw members may be manually tightened.

The loosely tightened second screw member has no function of transmitting the axial force of the tunnel from one girder to the other girder. Therefore, when a reaction force acts on the girder integrated segment 10 in a state where the second screw member is loosely tightened, there is little reaction force directly transmitted between the girder portions adjacent in the axial direction of the tunnel, and Most of the force is transmitted directly between the segments.

Since each connecting plate 30 is attached to one of the girder portions 14 to be connected to each other, a reaction force caused by the rotation of the cutter of the excavator and a cross-direction in the tunnel generated at the time of excavating a curved portion. It resists loads and prevents displacement of the spar-integral segments due to such reaction forces and loads.

The reaction force acting on the segment during excavation is absorbed by the ground around the segment, and becomes smaller as the reaction force acts on the segment on the rear side. For this reason, the loosely tightened second screw member is, for example, a reaction force acting on the girder integrated segment after the plurality of girder integrated segments are arranged in front of the girder integrated segment connected by the second screw member. Is so small that it does not affect the design of the girder and the screw member, and is then fully tightened with the designed torque and tightly tightened.

As described above, when the girder is not affected by the reaction force caused by the thrust for moving the excavator forward during excavation, it is not necessary to design the girder based on such reaction force.
There is no need to determine the mechanical strength of the girder, girder and its joint by the thrust at the time of tunnel construction. As a result, rational and economical design of the girder is possible, and the dimensions of the girder, connecting plate and screw member can be reduced, the workability of assembling them is good, and the degree of freedom of their design is improved. Large, the position of the jack that generates thrust is not limited,
Various advantages result, such as being advantageous for directional control of shielded excavators.

When the second screw member is strongly tightened, the adjacent girder portions are tightly connected to each other and have a function as a girder. For this reason, when the second screw member is strongly tightened,
The temporary pillar 38 supporting the corresponding girder integral segment is removed.

When the above-mentioned spar-integrated segment 10 is also used as a lower wing segment as shown in FIG. 5, the lower wing segment is assembled to an existing segment in the same manner as the upper wing segment, and The lower end of the pillar 34 is supported by the girder of the lower wing segment. Although not shown, the lower end of each temporary pillar is also supported by the girder of the lower wing segment.

The permanent pillar 34 may be provided instead of one temporary pillar 38 as described above, or may be assembled after the temporary pillar 38 is removed. The temporary pillar 38 need not be used.

According to the present invention, not only a girder receiving a load of a wing segment disposed at a portion corresponding to an intersection of two circles of a tunnel having a multi-circular cross section but also a load of a segment disposed at another portion are provided. The present invention can also be applied to the construction of other girders, such as girders to receive, and girder to receive the load of a segment used for lining a tunnel having a single circular cross section.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a part of a lining for explaining an embodiment of the present invention.

FIGS. 2A and 2B are views showing an embodiment of a girder integrated segment used in the present invention, wherein FIG. 2A shows an embodiment of a segment supported by a temporary column, and FIG. 1 shows an embodiment of a segment according to the present invention.

FIG. 3 is a front view showing an embodiment in which a plurality of beam integrated segments are connected.

FIG. 4 is a sectional view taken along line 4-4 in FIG. 3;

FIG. 5 is a perspective view showing one embodiment of a continuous state when the girder integrated segment shown in FIG. 1 is used as upper and lower wing segments.

[Explanation of symbols]

 10 girder integrated segment 12 segment part 14 girder part 30 connecting plate 32 notch through which connecting plate is passed 34 main pillar 38 temporary pillar

Claims (2)

(57) [Claims] An integrated girder segment integrally including a lining segment portion and a girder portion receiving a load acting on the segment portion is sequentially arranged in the axial direction of the tunnel along with the excavation of the tunnel. A plurality of first screw members for connecting the segment portions of the spar-integrated segments adjacent in the axial direction, and a plurality of connections in which the spar portions of the spar-integrated segments adjacent in the axial direction of the tunnel are attached to one of the spar portions. Connecting the plate with a plurality of second screw members, wherein during assembly of the segments, each first screw member is tightened, and the second screw member is loosely tightened, and the second screw member is loosely tightened. The second screw member is strongly tightened after the plurality of spar-integrated segments are disposed in front of the spar-integrated segments connected by the loosely-tightened second screw member. And a method of constructing a tunnel girder. 2. The method according to claim 1, further comprising supporting the corresponding girder integrated segment with a temporary column until the second screw member is strongly tightened.