JP2004324140A - Prestress introduction method for lining body and segment for lining body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a prestress introduction method for a lining body with excellent construction efficiency and high safety without requiring a large-scale apparatus and a segment for the lining body. <P>SOLUTION: A prestress is introduced into each segment 1 beforehand by fixing both ends of a PC steel material into which a tension force P1 is introduced to the joint plate of a joint between segments. When the segments 1 are assembled in a ring-shape in a construction site for a shield tunnel, a tightening force P2 according to the prestress introduced into the segments 1 is introduced between the joint plates 2 of the adjacent segments 1 and the joint plates 2 are tightened to each other so as to introduce a generally uniform prestress into the entire part of the segment ring. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for introducing a prestress into a lining body constructed by a shield method or the like and a lining body segment used in the method.
[0002]
[Prior art]
2. Description of the Related Art In recent years, there is a technical trend in shield tunnels in which a secondary lining is omitted for the purpose of improving economy and workability while increasing the depth and cross section of the shield tunnel.
[0003]
Generally, shield tunnel linings are constructed by assembling factory-produced segments downhole. The assembled segments need to be tightly integrated so as to withstand the soil pressure acting on the tunnel, and there is a method of introducing prestress in the circumferential direction of the concrete segment.
[0004]
Techniques for introducing a prestress into a segment ring include, for example, those described in Patent Literatures 1 to 3, which solve the problem of the cost of fittings and the troublesome work of tightening fittings in conventional segments. It is intended for.
[0005]
In each of these, after assembling a plurality of segments to form a segment ring, a PC steel material is penetrated all around the ring, tension is introduced to the PC steel material on site, and both ends are cut out on the inner surface of the segment ring. The prestress is introduced into the lining body by fixing to the lining.
[0006]
In Patent Document 4, an unbonded PC steel material is embedded in a segment in advance, and when assembling the segments, tension is introduced into the PC steel material at a connection between joints provided at both ends of the unbonded PC steel material. A method is described.
[0007]
As a conventional segment fitting, a bolt fastening type fitting has been generally used for a long time. On the other hand, for example, various types of cotter type fittings as disclosed in Patent Documents 5 to 7 have been developed.
[0008]
Cotter type fittings are often used for inter-segment joints which fasten segments to each other in the circumferential direction of the tunnel. In many cases, fastening and fastening in the circumferential direction of the tunnel can be performed simultaneously.
[0009]
In addition, for example, in Patent Literature 8, a worm wheel nut is provided on the outer periphery of a male joint fitted to a female joint on a joint surface, and the worm wheel nut is rotated by a worm from the thickness direction of the segment to reduce the tightening force. It describes that it can be introduced, and has the feature that it can be retightened even after the segments have been assembled.
[0010]
[Patent Document 1]
Japanese Patent Application Laid-Open No. Hei 10-046991 [Patent Document 2]
JP-A-10-238294 [Patent Document 3]
Japanese Patent Application Laid-Open No. H11-081891 [Patent Document 4]
JP 2001-248394 A [Patent Document 5]
JP 08-218784 A [Patent Document 6]
JP 2002-021487 A [Patent Document 7]
JP 2002-121999 [Patent Document 8]
JP 2001-323788 A
[Problems to be solved by the invention]
The conventional method of introducing prestress into a lining body is a method of introducing prestress on site when assembling a segment ring as described above.
[0012]
In this case, since the steps of inserting and tensioning the PC steel material intervene at the time of assembling the segments, it is difficult to speed up and simplify the joint fastening, and there is a problem in workability. In addition, since a large-scale device for inserting and tensioning the PC steel is required, it is difficult to automate the assembling work, and there is a problem in safety.
[0013]
In addition, the introduction of prestress is generally performed by tensioning a PC steel material arranged in the circumferential direction in the lining. For this purpose, the end of the PC steel material is pulled out inside the tunnel, and tension is applied. With force applied, this end must be anchored. For this reason, there is a problem that a notch for accommodating the fixing member is required, and that portion becomes a structural weak point.
[0014]
In addition, the force acting on the lining body is different between when assembling the segment and when the lining body receives the soil pressure from the ground or the internal water pressure from the inside as a ring, and in the segment mainly composed of concrete, There is a possibility that cracks may occur in the concrete near the joint due to a special load such as excessive pulling by the joint fitting during assembly.
[0015]
The present invention is intended to solve the above-mentioned problems when introducing prestress into a lining body using a segment mainly composed of concrete and assembling the segment, and requires a large-scale apparatus in construction. It is an object of the present invention to provide a prestress introduction method and a liner for a lining body having excellent workability and high safety.
[0016]
[Means for Solving the Problems]
The method for introducing a prestress of a lining body according to claim 1 of the present application is to provide a joint material that constitutes an inter-segment joint at both ends in the circumferential direction of a segment mainly composed of concrete, and a steel material having both ends fixed to the joint plate. A prestress is introduced into the concrete of the segment through the segment, and when the segments are assembled into a ring shape to form a segment ring, the prestress introduced into the segment between the joint plates between the adjacent segments is used. It is characterized in that the joint plates are fastened by introducing a tightening force.
[0017]
The pre-stress may be any of a post-tension type and a pre-tension type, and may be a chemical pre-stress type.
[0018]
The segments in the present invention are prestressed concrete segments (hereinafter, referred to as “PC segments”) in which prestress is introduced for each segment, and the PC segments are assembled into a ring shape to form a segment ring. .
[0019]
In the case of the post-tension system, for example, prestress is introduced by fixing both ends of a PC steel material passed through a sheath embedded in concrete to a joint plate. In such a case, the sheath is filled with grease or the like, and an unbonded PC segment is formed, or a slow-hardening resin is injected into the gap between the sheath and the PC steel material. It can be a so-called after bond.
[0020]
In the case of the pretension method, for example, a PC steel material fixed to a joint plate at the time of manufacturing a segment is set while applying tension, or a tension is applied to the PC steel material at the time of setting a formwork, and the PC steel material is fixed to the joint plate, and the concrete struck. There is a method of introducing and prestressing a segment by setting and curing, but a specific method of introducing a pretension is not particularly limited.
[0021]
In the chemical prestressing method, a steel material is set in a mold in the same manner as a normal segment, and a prestress is included in the segment by adding an expansive material to the concrete to be cast. If the effect of increasing the pretension is expected, the amount of steel such as reinforcing steel, PC steel, and shaped steel is increased, and the steel is fixed to the joint plate.
[0022]
Before assembling the segment ring, each PC segment is individually pre-stressed, and PC steel can be fixed to the joint plate and pre-stress can be introduced at the factory where the segment is manufactured. The construction site does not require a device or the like for tensioning the PC steel material.
[0023]
In the present invention, the joint plate functions as a bearing plate for introducing a prestress by fixing the end of the PC steel material or another steel material in addition to the joint function for connecting the original segments. have.
[0024]
In this case, simply connecting the PC steel or another steel at the inter-segment joint position breaks the prestress introduced into the PC segment at the joint position, and provides sufficient strength and rigidity as the entire segment ring. Absent.
[0025]
According to the invention of the present application, in connecting the PC segments, a prestress is introduced in the circumferential direction of the segment ring by introducing a tightening force between the joint plates in accordance with the prestress introduced into the PC segments, so that the conventional multiple The same strength and rigidity as in the case where prestress is introduced in the circumferential direction of the segment ring by a PC steel material penetrating the segment can be given to the lining body.
[0026]
Here, the introduction of the tightening force according to the pre-stress introduced into the PC segment means that the pre-stress acts almost uniformly on the entire circumference of the segment ring in principle. It may be modified according to conditions and design.
[0027]
Claim 2 limits the case where the joint plate is provided over the entire length of the joint surface between the segments in the tunnel axial direction in the method for introducing prestress of a lining body according to claim 1.
[0028]
In the present invention, since the joint plate also serves as a support plate for introducing prestress as described above, the joint plate extends over the entire length of the inter-segment joint surface in the tunnel axial direction, so that concrete for the PC segment can be used. In addition, prestress can be introduced almost equally.
[0029]
In the prestressing method for a lining body according to claim 3 or claim 1, the case where the joint plate covers the entire surface of the inter-segment joint surface is limited.
[0030]
According to a third aspect of the present invention, the structure of the second aspect is further advanced, and the joint plate is formed integrally to cover the entire surface of the inter-segment joint surface, so that prestress can be more evenly introduced. In addition, since the joint plate is integral with the adjacent segments, there is an advantage that rigidity can be easily secured against the introduction of a tightening force.
[0031]
The segment for a lining body according to claim 4 of the present application is provided with joint plates constituting an inter-segment joint at both circumferential ends of a segment mainly composed of concrete, and the both ends are fixed via a steel material fixed to the joint plate. A segment for a lining body obtained by introducing a prestress into concrete of a segment, wherein the inter-segment joint is a joint capable of introducing a tightening force according to the prestress by the steel material between joint plates between adjacent segments. Is used.
[0032]
The lining body segment according to claim 4 is a PC segment to be applied to the prestress introduction method according to claim 1, and the type and structure of the inter-segment joint has a tightening force necessary for coupling between joint plates. There is no particular limitation as long as it can be obtained, and conventional bolt-type joints, various cotter-type joints, or worm wheel-type joints described in Patent Document 8 described above can be used. .
[0033]
Claim 5 restricts the case where the inter-segment joint is a cotter type joint in the lining body segment according to claim 4.
[0034]
In the case of the cotter type joint, conventionally, a wedge-shaped metal piece is inserted from the inner side of the tunnel into the tapered groove embedded in the inter-segment joint surface as in the invention described in Patent Document 4 to obtain a tightening force (in this case, the tapered groove). Are also opened on the inner surface side of the tunnel.) And a wedge-shaped metal piece is inserted in the tunnel axial direction to obtain a fastening force (horizontal cotter) as in the inventions described in Patent Documents 5 and 6, and in the latter case, According to the present invention, there is an advantage that the inner surface of the segment can be completely smoothed because the PC steel material does not require a notch on the inner surface side of the tunnel.
[0035]
Furthermore, in the latter case, the joint between the ring in the tunnel axis direction and the circumferential direction can be simultaneously performed by using the pin-type joint hardware together with the inter-ring joint for fastening the segments in the tunnel axis direction. There is an advantage that you can.
[0036]
Claim 6 limits the case where the inter-segment joint is a bolt-fastened joint in the lining body segment according to claim 4.
[0037]
Also in the case of a bolt-type joint, prestress can be made continuous in the circumferential direction of the segment ring by controlling the tightening force of the bolt.
[0038]
According to a seventh aspect, in the lining body segment according to the fourth aspect, the inter-segment joint is fitted with a male joint projecting from the joint surface of the other segment into a female joint opening on the joint surface of the adjacent one segment. The male joint is pulled out in the axial direction by rotating a worm wheel nut provided on the outer periphery of the male joint with a worm gear inserted into a drive hole formed in the segment on the female joint side, thereby pulling out the male joint. This is limited to the case of a worm wheel type joint in which a tightening force is introduced.
[0039]
A feature of the worm wheel type joint is that it can be retightened later to obtain a necessary tightening force. In addition, it is also possible to provide a similar worm wheel type retightening mechanism in the middle of the segment instead of the joint portion as in claim 7.
[0040]
Claim 8 restricts the case where the joint plate is provided over the entire length of the joint surface between the segments in the tunnel axial direction in the lining body segment according to any one of claims 4 to 7.
[0041]
The ninth aspect limits the case where the joint plate covers the entire surface of the inter-segment joint surface in the lining body segment according to any one of the fourth to seventh aspects.
[0042]
These effects of claims 8 and 9 correspond to claims 3 and 4.
[0043]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a cross-sectional view perpendicular to the tunnel axis direction for explaining the basic principle of the method for introducing prestress of a lining body of the present invention. In the figure, five PC segments 1 are assembled to form a tunnel lining body. One segment ring of A is formed.
[0044]
As shown in FIG. 2, each PC segment 1 has a tapered engagement which constitutes an inter-segment joint at both ends (only one end is shown in FIG. 2) of a concrete segment main body having reinforcing bars 11 arranged therein. A joint pipe 2 having a groove 3 is embedded, and a sheath pipe 4 is embedded so as to connect between the joint plates 2 at both ends in the circumferential direction of the segment body. As shown in FIG. the tension force P ₁ is introduced, by fixing the ends of the PC steel 5 to the joint plate 2, it is introduced a predetermined prestress p ₁ in the concrete.
[0045]
Thus configured the PC segment 1, when assembled in a ring shape as shown in FIG. 1, in the segment between the joint surfaces a, by introducing a clamping force P ₂ to the joint plates, previously introduced into PC segment 1 is continuously prestressed p ₁ in the circumferential direction was (however, the magnitude of stress as a prestress varies by the load conditions and other), a substantially uniform prestress entire segment ring will act.
[0046]
The joint plate 2 is preferably formed of ductile cast iron because it is necessary to form the fixing portion of the PC steel material 5 and the above-described engagement groove 3. However, the strength required for the joint plate 2 also serving as a supporting plate is desirable. Is not particularly limited as long as is obtained.
[0047]
FIGS. 4 and 5 show one embodiment of the PC segment 1 when a cotter type joint is used for the inter-segment joint.
[0048]
FIG. 4 shows a case in which the joint plate 2 extends over the entire length in the tunnel axial direction on the inter-segment joint surface a in a range where the joint plate 2 is sandwiched by the upper and lower (outer and inner surface sides of the segment) seal grooves 9. Water is prevented from completely penetrating from the ground on the surface a.
[0049]
FIG. 5 shows a case in which the joint plate 2 is provided so as to cover the entire surface of the inter-segment joint surface a, which has an advantage that prestress and tightening force can be uniformly and efficiently introduced.
[0050]
In the embodiment of FIG. 4 or FIG. 5, when manufacturing the PC segment 1, the joint plate 2 is pre-attached to the inter-segment joint surface a of the main body of the concrete segment so that the joint plates 2 at both ends are connected. A sheath tube for inserting the PC steel is embedded in the concrete.
[0051]
The joint plate 2 is integrally formed with a reinforced opening 6 for inserting and fixing a PC steel material and a tapered engaging groove 3 for engaging a horizontal cotter used for an inter-segment joint. .
[0052]
Further, in the present embodiment, a pin-type joint hardware (male joint shown in FIG. 3) that can be fastened to the inter-ring joint surface b by merely inserting it in the axial direction by using, for example, the principle of a hole-in anchor. 7 and female joint 8) are provided.
[0053]
The above hardware is installed before casting concrete, and after hardening of the concrete, the PC steel material is directed from the opening 6 of one joint plate 2 on the segment joint surface a to the opening 6 of the joint plate 2 on the opposite side. The PC segment 1 is formed by introducing a tension and fixing it at the position of the opening 6 of the joint plate 2 and introducing a prestress to the segment body.
[0054]
The assembly of the PC segment 1 in the shield tunnel mine is performed by fastening the pin type joint of the inter-ring joint surface b in the tunnel axial direction by using the force of the erector or the shield jack. When the horizontal cotter is engaged with the engagement groove 3, a tightening force is introduced between the joint plates 2 at the inter-segment joint surface a, and a prestress continuous in the circumferential direction is introduced.
[0055]
FIG. 6 shows an embodiment in which a bolt-type joint is used as an inter-segment joint.
[0056]
When the PC segment 1 is manufactured, a joint plate 2 is pre-attached to an inter-segment joint surface a of a concrete segment main body, and a sheath tube for inserting a PC steel material so as to connect between the joint plates 2 at both ends is formed of concrete. There is provided a reinforced opening 6 which is embedded in the joint plate 2 to insert and fix the PC steel material in the joint plate 2. After the concrete is hardened, the PC steel material is inserted into the sheath tube, and tension is introduced to introduce the joint plate 2 into the sheath plate. 4 and 5 in that the PC segment 1 is formed by fixing at the position of the opening 6 and introducing prestress into the segment body.
[0057]
In the embodiment of FIG. 6, since the inter-segment joint is a bolt fastening type, a bolt hole 10 for bolt joining is formed in the joint plate 2, and when assembling the PC segment 1 in the shield tunnel, the bolt is used. By introducing a clamping force between the joint plates 2, a prestress that is continuous in the circumferential direction is generated.
[0058]
FIG. 7 is a cross-sectional view perpendicular to the tunnel axis direction when the PC steel 5 in the segment ring is arranged in an elliptical shape having a larger diameter in the horizontal direction than in the vertical direction.
[0059]
Generally, the force acting on the tunnel lining body A is slightly larger in the vertical direction than in the horizontal direction, and the arrangement of the PC steel members 5 in a state where the segments 1 are connected in the circumferential direction as shown in FIG. Is made slightly elliptical in the vertical direction, a force is exerted to return the segment ring from the PC steel material 5 to a circular shape, and the roundness at the time of completion is increased. If designed to).
[0060]
FIG. 8 shows one segment 1 in a case where prestress is introduced in a chemical prestress manner in the present invention, and a PC steel material 5 or a rebar, or Set a steel material such as a section steel. By adding an expansive material to the concrete to be poured, prestress is introduced into the segments as the concrete hardens. In the figure, reference symbol c conceptually shows the expansion pressure of the expandable material in the concrete.
[0061]
The prestress is introduced by the contact (friction) between the concrete and the steel, in addition to the expansion pressure of the concrete being introduced through the joint plates 2 at both ends fixed to the steel such as the PC steel 5 or the reinforcing steel or the shaped steel. can do.
[0062]
For example, when the required pre-stress is small, a shaped steel or the like having irregularities or dowels on the surface can be used instead of the PC steel material 5. This is the same for other embodiments of the present invention.
[0063]
FIG. 9 shows an outline of a method of manufacturing the segment 1 in the case where prestress is introduced by a pretension method in the present invention.
[0064]
In this example, the PC steel material 5 is set on the joint plate 2 (end plate) while tension is applied at the time of segment production, or the PC steel material 5 is set at the time of setting the formwork 21 by fixing the PC steel material 5 to the joint plate 2, Introduce and cure concrete to introduce prestress into segments.
[0065]
FIG. 10 and FIG. 11 show the structure of the joint portion of the embodiment when the prestress is introduced by unbonded PC steel in the present invention.
[0066]
The PC steel material 5 is passed through the sheath tube 4 filled with grease or the above-mentioned after-bonding resin and the like, and after the concrete of the segment 1 is hardened, the PC steel material 5 is tensioned to introduce a required prestress, and both ends are jointed. Fix to plate 2 (end plate).
[0067]
For example, by fitting the tapered cotter joint 12 to the female joint formed on the joint plate 2, the segments 1 on both sides of the joint surface are drawn together (the interval becomes narrower from the open state in the figure).
[0068]
In the embodiment of FIG. 11, the edge plate 13 is provided on the joint plate 2 to which the end of the PC steel material 5 is fixed, and when the adjacent segments 1 are attracted to each other by the cotter joint 12, the edge 1 The PC steel fixing portion 2a inside the edge cut portion 13 is relatively displaced with respect to the main body portion of the joint plate 2 in contact with the concrete, so that an unreasonable tensile force does not act near the main body of the joint plate 2.
[0069]
That is, the tensile force generated at the joint portion when assembling the segment 1 is applied only to the steel material so that the main concrete that cannot withstand the tensile force is not cracked.
[0070]
【The invention's effect】
According to the present invention, the rigidity of the segment main body is increased by introducing a pre-stress into the segment main body in advance, and by assembling the segment ring while introducing the tightening force to the segment joint, the circumferentially continuous pre-stress is reduced. It can be introduced and the rigidity of the segment ring is improved.
[0071]
In order to introduce prestress into the segment body in advance, it is possible to correspond to various joints, for example, by providing a pin type joint on the inter-ring joint surface and providing a horizontal cotter type joint on the segment joint surface, Simultaneous tightening force can be introduced at the time of assembling the segments, and improvement in workability such as speeding up, automating, and high-speed fitting can be expected.
[0072]
Further, in the present invention, since the tension fixing portion of the PC steel material is located on the segment joint surface, the fixing portion of the PC steel material is not exposed on the inner side of the tunnel, and a cutout portion for fixing the PC steel material is provided in the segment body. Since there is no need, it is possible to prevent a structural weak point from occurring.
[0073]
Further, by using a joint of a pin type or a joint of a horizontal cotter type, it is also possible to completely smooth the inner surface side of the segment.
[0074]
Pre-stress is introduced into the segment in advance against the effects of special loads during construction, such as when a large tensile force is applied to the joint surface by tightening with the joint during assembly, so that the segment body such as cracks in concrete near the joint The influence on the parts can be suppressed. In particular, in the case of the unbonded type, the joint and the main body are cut off so that the effect of suppressing cracking is large.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view perpendicular to the tunnel axis direction for explaining the basic principle of a method for introducing prestress into a lining body according to the present invention.
FIG. 2 is a schematic view showing an arrangement example of a sheath tube for passing a joint plate and a PC steel material.
FIG. 3 is a cross-sectional view for explaining transmission of prestress in the present invention.
FIG. 4 is a perspective view showing one embodiment of a PC segment when a cotter type joint is used as an inter-segment joint.
FIG. 5 is a perspective view showing another embodiment of the PC segment when a cotter type joint is used as the inter-segment joint.
FIG. 6 is a perspective view showing an embodiment of a PC segment in the case where a bolt-type joint is used as an inter-segment joint.
FIG. 7 is a cross-sectional view perpendicular to the tunnel axis direction when the arrangement of the PC steel material in the segment ring is an elliptical arrangement having a larger diameter in the horizontal direction than in the vertical direction.
FIG. 8 is an explanatory diagram in a case where prestress is introduced by a chemical prestress method in the present invention.
FIG. 9 is a perspective view for explaining a case where prestress is introduced by a pretension method in the present invention.
FIG. 10 is a cross-sectional view of a joint position in an example of the case where prestress is introduced by unbonded PC steel in the present invention.
FIG. 11 is a sectional view of a joint position in another example in the case where prestress is introduced by unbonded PC steel in the present invention.
[Explanation of symbols]
A: tunnel lining body, a: joint surface between segments, b: joint surface between rings, c: expansion pressure of the expanding material,
DESCRIPTION OF SYMBOLS 1 ... PC segment, 2 ... Joint board, 2a ... PC steel fixing part, 3 ... Engagement groove, 4 ... Sheath tube, 5 ... PC steel, 6 ... Opening, 7 ... Male joint (joint between rings), 8 ... Female joint (joint between rings), 9: seal groove, 10: bolt hole, 11: rebar, 12: cotter joint, 13: rim, 21: formwork

Claims (9)

A joint plate constituting an inter-segment joint is provided at both ends in the circumferential direction of a segment mainly composed of concrete, and prestress is introduced into concrete of the segment via steel materials having both ends fixed to the joint plate, and the segment is pre-stressed. When assembling each other into a ring to form a segment ring, the joint plates are fastened by introducing a tightening force according to the prestress introduced into the segment between the joint plates of adjacent segments. Prestressing method for lining body. The prestress introduction method for a lining body according to claim 1, wherein the joint plate is provided over the entire length of the joint surface between the segments in the tunnel axial direction. 3. The method of claim 1, wherein the joint plate covers the entire surface of the inter-segment joint surface. A lining body in which joint plates constituting an inter-segment joint are provided at both ends in the circumferential direction of a segment mainly composed of concrete, and prestress is introduced into the concrete of the segment via a steel material having both ends fixed to the joint plate. A segment for a lining body, characterized in that a joint capable of introducing a tightening force according to the prestress of the steel material between joint plates between adjacent segments is used as the inter-segment joint. The segment for a lining body according to claim 4, wherein the inter-segment joint is a cotter type joint. The segment for a lining body according to claim 4, wherein the inter-segment joint is a joint of a bolt fastening type. The inter-segment joint is fitted with a male joint projecting from the joint surface of the other segment into a female joint opening on the joint surface of one of the adjacent segments, and the worm wheel nut provided on the outer periphery of the male joint. A worm wheel type joint in which the male joint is pulled out in the axial direction by rotating with a worm gear inserted into a drive hole formed in the female joint side segment, and a tightening force is introduced between the joints. The segment for a lining body according to claim 4, characterized in that: The lining body segment according to any one of claims 4 to 7, wherein the joint plate is provided over the entire length of the joint surface between the segments in the tunnel axial direction. The lining body segment according to any one of claims 4 to 7, wherein the joint plate covers an entire surface of the joint surface between the segments.

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