JPS63142191A - Method of executing curve section of shield tunnel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention "Industrial Application Field" The present invention is applicable to the curved construction part of a shield tunnel in which a tunnel is formed by excavating the ground with a shield machine while lining the excavated wall with segments. ``Conventional Technology'' Conventionally, there is a method for constructing curved sections of shield tunnels using tapered segments.

What is indicated by the reference numeral 20 in FIG. 4 is a tapered segment. This tapered segment is configured such that when assembled in an annular shape, one inter-ring joining end surface 20a forms an angle with the other inter-ring joining end surface 20b formed opposite thereto. By sequentially connecting the segment rings made up of the above, the cylindrical structure 21 made up of the segments can gradually change its direction.

"Problems to be Solved by the Invention" In recent years, with the advancement of shield tunneling machines, construction of sharp curves in shield tunnels has become easier than before, and the demand for such construction has been increasing.

However, when excavating a sharp curve using a shield machine,
In the above-mentioned conventional construction method, when the shield machine changes direction, a phenomenon occurs in which the tail portion of the shield machine swings significantly in the direction opposite to the direction in which the cutter portion at the tip thereof faces. For this reason, there was a problem in that the tail portion of the shielding machine came into contact with the lining segment, and the direction could only be changed up to a certain degree.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method for constructing a curved portion of a shield tunnel, which effectively realizes construction of a sharply curved portion.

"Means for Solving the Problems" The method for constructing curved sections of shield tunnels according to the present invention covers curved sections with reduced diameter segments that have a smaller outer diameter than normal segments used for straight sections. and a step of interposing an irregularly shaped segment between the reduced diameter segment and the normal segment, one joining end surface matching the normal segment and the other joining end surface matching the reduced diameter segment. It is characterized by having.

"Operation" Since a wide gap is secured between the shield machine and the segment, it is possible to increase the turning angle of the shield machine.

Moreover, the junction between the normal segment used in the straight construction part and the reduced diameter segment used in the curved construction part does not form a stepped part because the irregularly shaped segment is interposed therein. ``Embodiment'' Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 3.

Figure 1 shows a shield tunnel (hereinafter abbreviated as tunnel) T, which has been constructed in a straight line from the right side of the paper to the left, and a curved section is being constructed in order to curve it to the left (downward on the paper). It shows. Reference numeral 15 indicates a shield machine. The linear construction portion Ts of the tunnel T is usually lined with general concrete segments l.

Constructing the curved construction section Tc following the straight construction section Ts is as follows.

First, the irregularly shaped segment 2 is joined to the joining end surface of the concrete segment l that constitutes the tip of the linear construction section Ts.

The irregularly shaped segment 2 is made of steel, and as shown in FIG.
An outer circumferential plate 4 attached to the convex side of the bearing pressure plate 3 across between these two bearing pressure plates, a connecting plate 5 provided at both ends of the opposing surface of the bearing pressure plate 3, and a plurality of connecting plates installed between the bearing pressure plates. It is composed of regular ribs 6 and is generally similar to a general steel segment. However, in the bearing pressure plate 3, the radius of curvature of the outer peripheral portion 7 of one bearing pressure plate 3A is smaller than the radius of curvature of the outer peripheral portion 80 of the other bearing pressure plate Fi, 3B. As a result, the outer circumferential plate 4 is
It is inclined toward the bearing pressure plate 3A. Further, the radius of curvature of the outer peripheral portion 8 of the bearing pressure plate 3B is the same as that of the concrete segment! The radius of curvature of the outer circumferential portion 7 of the pressure bearing plate 3A is equal to the radius of curvature of the outer circumferential portion of the reduced segment 10, which will be described later. Furthermore, the connection plate 5 has a V-shape that slightly narrows as it goes from the bearing pressure plate 3B to the bearing pressure plate 3A, so that a plurality of irregularly shaped segments 2 are assembled into a ring shape by joining the connection plates 5. At this time, a so-called truncated cone shape is formed, with the joint end surface 2b formed by the bearing pressure plate 3B serving as the bottom surface and the joint end surface 2a comprising the bearing pressure plate 3A serving as the top surface.

The ribs 6 are similar to those constituting ordinary steel segments and have a cross-sectional shape. Further, in this embodiment, regarding the bolt holes 9 drilled in the bearing pressure plate 3, one bearing pressure plate 3A having a smaller radius of curvature on the outer circumference has a larger number than the other bearing pressure plate 3B. It becomes.

As shown in FIG. 3, the irregularly shaped segment 2 constructed as described above is joined by bringing its joining end surface 2b into contact with the joining end surface 1a of the concrete segment I. The joining is carried out using bolts and nuts using the bolt holes 9, similar to the joining of ordinary segments. The irregularly shaped segment 2 joined to the joint end surface 1a of the concrete segment 1 and assembled in an annular shape forms a truncated cone shape, and the cylindrical body constructed by the concrete segment 1 is formed so that its tip is tapered. The state will be as follows.

Next, a segment for lining the curved construction portion Tc, a reduced diameter segment 1O, is joined and connected to the annularly assembled irregularly shaped segments 2.

The reduced diameter segment 10 is a steel taper segment that is normally used in the construction of curved sections, but its outer diameter (outer radius of curvature) is smaller than the concrete segment l used for lining the straight construction section Ts, The radius of curvature of the irregularly shaped segment 2 is formed to be the same as the outer circumferential diameter (outer circumferential curvature radius) of the joint end surface 2a, which is formed to be small. The irregularly shaped segment 2 and the reduced diameter segment 10 may be joined by conventional means for joining steel segments together.

Here, the number of bolt holes 9 is different between one joint end surface 2a and the other joint end surface 2b, but this is because concrete segments generally have fewer joints than steel segments. This is because one joint end surface 2b is joined to the concrete segment 1, while the other joint end surface 2a is joined to the steel segment 10.

When the tapered segment, that is, the reduced diameter segment 10 is propelled by a jacking reaction force, the shield JfAts gradually changes its traveling direction.

FIG. 3 shows the pattern of the shield machine 15 at the beginning of bending. When the tail seal 16 of the shield machine 15 moves from the concrete segment 1 to the reduced diameter segment IO, the tail seal 16 slides on the slope formed by the outer peripheral plate 4 of the irregularly shaped segment 2 and reaches the reduced diameter segment IO.

Therefore, the tail seal 16 does not separate from the back surface of the segment at this portion where the outer circumferential diameter of the segment changes, and the sealed state is maintained, and there is no tail seal.

The curve construction section Tc is constructed exclusively using the reduced diameter segment 1O. The gap between the reduced diameter segment 1 and the shield machine 15 becomes wider, and the shield machine 15 can obtain a correspondingly larger turning angle, and as a result, it becomes possible to form a sharp curve. Once the direction change has been made at the desired angle, the reduced diameter segment forming the terminal end of the curved construction section Tc! 0
Then, the same irregularly shaped segment 2 as described above is connected so that its joining end surface 2a abuts on this reduced diameter segment IO. Thereafter, if the concrete segment 1 is connected to the other joint end surface 2b of the irregularly shaped segment 2, the tunnel T will be constructed in a straight line again.

In the embodiment, the irregularly shaped segment 2 is made of steel, but if necessary, it may be made of concrete, and even in that case, the operation is the same as described above.

"Effects of the Invention" As explained above, according to the present invention, in the curved section construction method of a shield tunnel, the curved section is replaced with a reduced diameter segment formed with a smaller outer diameter than the normal segment used for the straight section. and a step of interposing, between the reduced diameter segment and the normal segment, an irregularly shaped segment whose one joint end face matches the normal segment and the other joint end face matches the reduced diameter segment. As a result, a wide gap is ensured between the shield machine and the segment, making it possible to increase the turning angle of the shield machine, thereby facilitating construction of sharp curves.

Moreover, since no step is formed at the joint between the normal segment used for straight construction sections and the reduced diameter segment used for curved construction sections, the tail of the shielding machine can be used even at this location where the outer diameter of the segment changes. The seal maintains its sealing state without separating from the back of the segment, which prevents underground water and backfill material from entering the tail of the shield machine, and has excellent effects such as not damaging the tail seal. play.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention,
FIG. 1 is a cross-sectional view showing the straight construction part and the curved construction part of the shield tunnel. FIG. 2 is a perspective view from the back of a deformed segment used in the method for constructing a curved portion of a shield tunnel according to the present invention. FIG. 3 is a partially sectional view illustrating one of the effects of the present invention. FIG. 4 is a sectional view for explaining a conventional example. T...Shield tunnel, Ts...
Straight line construction part, Tc...Curved construction part, l.
...Concrete segment, 2...
- Irregular segment, 2a... one joint end surface, 2b... other joint end surface, 10...
...Reduced diameter segment. Applicant Ishikawajima Kenzai Kogyo Co., Ltd. 1 TO!

Claims (1)

[Claims] In the shield tunnel curved section construction method, a step of lining the curved section with reduced diameter segments formed with a smaller outer diameter than the normal segments used for the straight construction section;
interposing an irregularly shaped segment between the reduced diameter segment and the normal segment, one of which has a joint end surface that matches the normal segment, and the other joint end surface that matches the reduced diameter segment. Construction method for curved sections of shield tunnels.