JP3229927B2 - Segment for shield tunnel lining and method for introducing prestress of shield tunnel lining - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield tunnel lining segment used for introducing a prestress in a circumferential direction of a shield tunnel lining body and a prestress to a shield tunnel lining body. On how to do it.

[0002]

2. Description of the Related Art Generally, the lining of a shield tunnel is
It is built by assembling factory-produced segments underground. The assembled segments need to be firmly integrated so as to withstand the earth pressure and water pressure acting on the tunnel, and there is a method of introducing prestress in the circumferential direction of the concrete segment.

[0003] The introduction of prestress is generally performed by tensioning a PC steel material arranged in a circumferential direction in a lining. For this purpose, an end of the PC steel material is pulled out inside a tunnel, and tension is applied. This end must be anchored with the force applied. For this purpose, a segment having a structure as shown in FIG. 7 has been conventionally used.

The segment 101 has a duct 102 through which a PC steel material is inserted. The duct 102 makes a round in the circumferential direction of the lining body and has both ends at the segment 101.
And open at the fixing end face 103a of the notch 103 provided on the inner surface of the segment.
The PC steel material inserted into the duct 102 is tensioned by using a center hole jack 104 to apply a reaction force to the concrete in the segment. Then, it is fixed to the segment using an anchor plate, a wedge or the like.

[0005]

However, the above-described conventional segment structure and prestress introduction method have the following problems. P
Since the C steel material is crossed at a part in the circumferential direction, the prestress is discontinuous at this part, and an eccentric moment is generated or the prestress becomes uneven. Also, P
Since the tension introduced into the C steel material is transmitted from the anchor end to the concrete in the segment, a large tensile stress may be locally generated in the concrete. Therefore, PC
It is necessary to reinforce the vicinity of the fixing end of the steel material with a reinforcing bar. For example, as shown in FIG. 8, many reinforcing bars must be arranged in a complicated combination.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to simplify the structure near the tension or anchoring end of a PC steel material and to uniformly prestress in the circumferential direction. It is an object of the present invention to provide a segment for a shield tunnel lining body and a method for introducing a pre-stress of the shield tunnel lining body into which a stress can be introduced.

[0007]

According to a first aspect of the present invention, there is provided a segment for constructing a shield tunnel lining body by assembling a plurality of segments in a circumferential direction . It is joined together so that the cylinder becomes X-shaped.
A fixing member having a curved shape,
The two ends of PC steel material arranged in the circumferential direction of the
Inserted into the two cylinders from both sides and fixed together
Fixing member is fixed between an inner peripheral surface and an outer peripheral surface of the segment.
A segment for a shield tunnel lining body characterized in that a notch is provided so that an end face of a fixing body for introducing tension into a PC steel material is exposed inside the shield tunnel lining body. It is.

According to a second aspect of the present invention, in the segment for a shield tunnel lining according to the first aspect,
It is assumed that the fixing member is embedded and fixed in the concrete of the segment.

According to the third aspect of the present invention, the two cylinders are
A fixing member having a shape integrally joined so as to form an X shape is fixed between an inner peripheral surface and an outer peripheral surface of a shield tunnel lining body, and a PC steel material arranged in a circumferential direction of the shield tunnel wherein the two ends from both sides of the fixing member
An object of the present invention is to provide a method for introducing a prestress into a shield tunnel lining body, wherein the prestress is inserted into and locked by two cylinders, and a tension is simultaneously applied and fixed to both PC steel materials.

[0010] In the segment for a shield tunnel lining body according to claim 1, two ends of the PC steel material integrally fixed to the fixing body are both ends when one PC steel material is arranged in a circumferential direction. Or two PC steel materials whose other ends are fixed at other positions.

The structure for fixing the fixing member may be fixed by embedding the fixing member in concrete of the segment as described in claim 2, or may be fixed to the inner side of the segment 51 as shown in FIG. It may be fixed in one provided notch 52 by an anchor bolt 53 or the like. At this time, the fixing body 54 must be disposed outside the circumferential surface of the segment so that the cover of the concrete can sufficiently be secured to the PC steel material and the fixing body itself.

Further, in the method for introducing a prestress of a shield tunnel lining body according to a third aspect, the fixing body may be buried in concrete in the same manner as described in the first aspect, or may be provided in the notch. May be fixed. In the prestressing method according to claim 3,
The two ends of the PC steel material that are inserted into and locked by the two cylinders of the fixing body may be tensioned by two jacks attached to both sides of the fixing body. As long as both ends of one PC steel material arranged around the lining body, tension may be applied to only one side and tension may be introduced to the opposite side.

[Operation] The invention according to the present application has the above-described configuration, and thus operates as follows. In the shield tunnel lining segment according to claim 1, the shield tunnel lining body
Two ends of PC steel material arranged in the circumferential direction
Since the fixing body that is inserted and fixed integrally is used, the PC
Most of the reaction force of the tension of the steel material becomes a compressive stress in the fixing body, and no large stress is generated in concrete. Therefore, reinforcing the concrete in the vicinity of the fixing end can be considerably simplified.

Further, since the fixing member is fixed to the segment, when the PC steel material arranged in the circumferential direction is fixed by tension, the fixing member is fixed from the fixing member to the concrete of the segment in the center direction of the curvature. The force acts and prestress is evenly introduced. In other words, PCs arranged in the circumferential direction
When tension is introduced into the steel material, as shown in FIG. 6, a force P1 toward the center of curvature acts on the concrete of the segment from the PC steel material 61 in the circumferential direction. In the portion where the fixing body 62 is disposed, the fixing body is pulled toward the center by the tension of the PC steel material, and the fixing body is fixed to the concrete, so that a force P2 toward the center acts on the concrete. Therefore, the force in the center direction becomes substantially uniform in the circumferential direction, and uniform prestress is introduced.

Further, since the fixing member is fixed between the inner peripheral surface and the outer peripheral surface of the segment, that is, within the range of the member thickness, even in a small-diameter tunnel, the PC steel material is kept near the fixing member. It is possible to maintain sufficient concrete covering. Further, since the notch is provided so that the end of the fixing body is exposed to the inside of the lining, the PC steel material can be tensioned from the inside of the lining when the segments are assembled.

In the segment for a shield tunnel lining body according to the second aspect, the fixing body is fixed in a state buried in concrete, so that the fixing body can be fixed at an accurate position when the segment is manufactured. This makes it possible to easily perform the tension / fixation work when introducing prestress.
Further, the notch for tensioning the PC steel material can be reduced, and the vicinity of the position where the fixing member is installed can be prevented from becoming a weak point.

According to the prestress introduction method for a shield tunnel lining body according to the third aspect, the P disposed in the circumferential direction is provided.
Since the ends of the C-steel material are wrapped from both sides and are integrally fixed to one fixing body, local large stress is not generated in the concrete of the lining body. In addition, it becomes possible to uniformly introduce prestress in the circumferential direction. Furthermore, when two tensions are simultaneously applied to the two ends of the PC steel fixed to one fixing body, a large stress is generated near the fixing body or the position of the fixing body moves. Is prevented.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view and a plan view showing a segment for a shield tunnel lining body according to an embodiment of the present invention. The segment 1 is a member made of concrete and having a curved cross section so as to constitute a part of a cylindrical curved surface, and is incorporated around a shield tunnel having a circular cross section as shown in FIG. It constitutes a lining body that resists pressure and water pressure.

The segment 1 shown in FIG. 1 is designed to be combined with three other segments 2, 3, and 4 having substantially the same shape to form an annular lining, and the circumferential direction in these members is changed. Is provided with a duct 4 for inserting a PC steel material. The duct 4 is provided so as to be continuous between the combined segments, and communicates with the fixing body 5 embedded in the segment of the present invention shown in FIG.

As shown in FIG. 3, the fixing member 5 is made of cast iron and has a shape in which two cylinders are integrally joined so as to form an X shape. The steel material goes around the inside of the lining, and both ends are drawn out to the inside of the lining through the two through holes 5a and 5b of the fixing body 5, respectively. For this reason, the notch 6 is provided inside the segment, and the end face of the fixing body 5 where the through hole is provided is exposed. Also, the through-hole 5 of this fixing body
As shown in FIG. 3, the diameters a and 5b are enlarged near the end exposed to the inside of the lining body, and the tensioned PC steel material is fixed to the fixing body by the wedge 7. You can do it.

The fixing member 5 is installed together with a reinforcing bar when concrete of the segment is cast, and is fixed by embedding in the concrete.
As shown in FIG. 4, the reinforcing bars include main reinforcing bars 8, 9 arranged along the inner surface and the outer surface of the segment, reinforcing bars 10 connecting them, reinforcing reinforcing bars 11, 12 around the fixing body, and the like.

Next, a process of assembling a lining body using the above-described segments for a shield tunnel lining body and introducing a prestress thereto will be described. This is also one embodiment of the invention described in claim 3. When the excavation at the face proceeds by one unit of the segment (L shown in FIG. 1) by the shield machine, as shown in FIG. 2, the segments 1, 2, 3, 4 are arranged at the rear of the shield machine.
Assemble.

Next, a PC steel material is inserted from the end face of the fixing body 5 into the through hole of the fixing body, and further the duct 4 in the segment is inserted.
Through. Then, the fixing body 5 is drawn out from the other through-holes in the circumferential direction to the inside of the lining body. As this PC steel material, it is desirable to use a steel stranded wire, but it may be a steel wire or a small-diameter steel rod.

One end (fixing end) of the PC steel is
As shown in FIG. 3, the fixing member 5 is fixed to the fixing member 5 by the wedge 7, and the other end (tensed end) is inserted into the R chair 13 and the center hole jack 14. This center hole jack 14
As a result, the PC steel material is gripped and, as shown in FIG. 2, the reaction force is applied to the fixing body 5 via the R chair 13 to tension the PC steel material. At this time, the tension introduced into the PC steel material is transmitted in the circumferential direction and reaches the fixing body 5 to cause the fixing body 5 to generate a reaction force in the opposite direction. Therefore, the compressive force substantially equal to the tension acts on the body of the fixing member 5, but almost no force is transmitted to the concrete. When a predetermined tension is applied to the PC steel, the wedge is pushed in similarly to the fixing end, and the PC steel is fixed to the fixing body 5. Thereafter, the center hole jack 14 and the R chair 13 are removed, and the extra length of the PC steel is cut, and then the notch 6 is filled with concrete to complete the lining body.

As described above, the tension and fixation of the PC steel material causes a distribution force in the direction of the center of curvature to act on the concrete from the PC steel material, thereby generating a circumferential axial compression force on the lining body. At this time, since the wrap length of the PC steel near the tension end and the fixing end of the PC steel is short, and both ends are fixed to one fixing body fixed in the concrete, a large stress may be generated locally. And the prestress is almost uniformly introduced. Further, since a large local stress does not act on the concrete around the fixing body, as shown in FIG. 4, the reinforcing reinforcing bar around the fixing body does not require much, and is greatly simplified as compared with the conventional example shown in FIG. Be transformed into

[0026]

As described above, in the shield tunnel lining body segment of the invention according to the present invention, a fixing body for integrally fixing PC steel materials that cross each other so as to wrap from both sides is used, and this is used as the lining body. Is fixed within the range of the thickness of the fixing member, no large stress is generated in the vicinity of the fixing member, and the reinforcing reinforcing bar can be greatly simplified. In addition, it is possible to introduce a substantially uniform pre-stress in the circumferential direction. Furthermore, even in a small-diameter tunnel, it is necessary to secure sufficient cover for the fixing body and the PC steel material and to reduce the notch in the concrete. Can be prevented from becoming a structural weak point. Further, in the method for introducing a prestress of a shield tunnel lining body according to the present application, it is possible to introduce a substantially uniform prestress in the circumferential direction without generating a large local stress in the concrete.

[Brief description of the drawings]

FIG. 1 is a sectional view and a plan view showing a segment for a shield tunnel lining body according to an embodiment of the invention described in claim 1 or 2;

FIG. 2 is a schematic sectional view showing a state where the shield tunnel lining body segment of FIG. 1 is assembled in a tunnel.

FIG. 3 is a cross-sectional view and a front view of a fixing body used in the shield tunnel lining body segment of FIG. 1;

FIG. 4 is a schematic view showing a reinforcing bar arranged in the shield tunnel lining body segment of FIG. 1;

FIG. 5 is a schematic diagram illustrating an example of a fixing structure of a fixing member.

FIG. 6 is a schematic diagram illustrating a force acting on concrete due to tension of a PC steel material.

FIG. 7 is a schematic sectional view of a conventional segment for a shield tunnel lining body.

FIG. 8 is a schematic view showing the arrangement of reinforcing bars of the shield tunnel lining body segment of FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 segment 2, 3, 4 segment 5 Fixing body 6 Notch 7 Wedge 13 R chair 14 Center hole jack

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shinichiro Kumagai 4 Sumitomo Construction, Inc., 13-13 Arakicho, Shinjuku-ku, Tokyo (72) Inventor Masashi Kaneko 4 Sumitomo Construction, 13-13 Arakicho, Shinjuku-ku, Tokyo (72) Inventor Taku Sagara 5 Yonbancho, Chiyoda-ku, Tokyo Toa Construction Industry Co., Ltd. (72) Inventor Norihiko Yokota 4-9-1-9 Akasaka, Minato-ku, Tokyo Inside Soil Development Co., Ltd. ( 72) Inventor Etsuji Ishibashi 1-3-12 Moto-Akasaka, Minato-ku, Tokyo Sumitomo Electric Industries, Ltd. (56) References JP-A-7-26896 (JP, A) (58) Fields investigated (Int. . ^7, DB name) E21D 11/08

Claims (3)

(57) [Claims] 1. A segment forming a shield tunnel lining body by assembling a plurality of pieces in a circumferential direction, wherein two segments are integrally joined so as to form an X shape.
A fixing body having the shield tunnel lining body
The two ends of the circumferentially arranged PC steel are forward from both sides
Fixing body that is inserted into two cylinders and fixed together
Is fixed between the inner peripheral surface and the outer peripheral surface of the segment , and the end surface of the fixing body for applying a reaction force to the fixing body to introduce tension into the PC steel material is covered with the shield tunnel lining. A segment for a shield tunnel lining body, wherein a notch is provided so as to be exposed inside the body. 2. The segment for a shield tunnel lining body according to claim 1, wherein the fixing member is embedded and fixed in concrete of the segment. . 3. The two cylinders are integrally connected so as to form an X shape.
A fixing member having a combined shape is fixed between the inner peripheral surface and the outer peripheral surface of the shield tunnel lining body, and two ends of the PC steel material arranged in the circumferential direction of the shield tunnel are fixed. Insert the two cylinders from both sides of the body
A prestressing method for a shield tunnel lining body, wherein tension is simultaneously applied to both PC steel materials to fix them.