JP5101050B2 - Segment unit - Google Patents

Description

  The present invention relates to a segment unit having a substantially rectangular or substantially U-shaped cross section constituting an underpass tunnel having a substantially rectangular or substantially U-shaped cross section.

An underpass tunnel that intersects with a track or a road is composed of a tunnel part and an approach part that connects the tunnel part and the ground. (For example, refer to Patent Document 1).
According to the shield construction method, an underpass tunnel can be constructed without excavating tracks and roads, so that the construction period and cost can be reduced, and the traffic network is not blocked.
In an underpass tunnel, it is preferable to make the depth of an intersection where a three-dimensional intersection with a track, a road, etc. is as shallow as possible and to shorten the extension of the approach portion. For this reason, the cross-section of the underpass tunnel is often a segment ring in which a plurality of segment pieces are constructed in a substantially rectangular shape. The tunnel cover has a substantially rectangular segment ring, and the approach cover has a cross-section. A substantially U-shaped segment having an upper portion opened from the configuration of the substantially rectangular segment ring is used.
JP 2005-248546 A

By the way, since many segment pieces are used in the underpass tunnel, if the lining part thickness (wall thickness) of each segment piece can be reduced, the cost of the segment piece is reduced and the construction cost is greatly reduced. can do. However, as shown in FIGS. 9A and 10A, the substantially rectangular segment ring and the substantially U-shaped segment constituting the underpass tunnel are always subjected to earth pressure, water pressure, groundwater from the four sides such as the underground and the ground surface. Pressure, and road loads such as vehicles and railway vehicles.
Therefore, when the lining portion thickness of these segment pieces is reduced, it corresponds to each side of a substantially rectangular segment ring or a substantially U-shaped segment as shown in FIG. 9B, FIG. 10B, or FIG. There is a possibility that the segment piece group of the portion may be deformed inwardly in a cross-sectionally concave shape, damaged or destroyed. In particular, the substantially rectangular segment ring and the substantially U-shaped segment have a drawback that the pressure is not easily dispersed as compared with a circular shape because the longitudinal cross-sectional shape is substantially rectangular.

  The present invention has been made in view of the above-mentioned problems. The pressure resistance of the segment group constituting the underpass tunnel having a substantially rectangular cross section is increased, and the segment piece thickness is made thinner than that of the conventional segment piece to reduce the cost. An object of the present invention is to provide a segment unit designed to achieve the above.

In order to achieve the above object, a segment unit according to the present invention is a substantially rectangular segment consisting of a plurality of segment pieces arranged in the circumferential direction or a substantially U-shaped segment unit open upward , A substantially box-shaped recess is formed on the inner peripheral surface side of the segment pieces at both ends of the plurality of segment pieces constituting each side , and the PC steel material is disposed in the plurality of segment pieces constituting each side of the segment unit. And the PC steel material is disposed closer to the inner peripheral surface than the center in the thickness direction of the plurality of segment pieces, and the PC steel material penetrating the plurality of segment pieces adjacent in the sides in the circumferential direction. was Tightened through both ends of the PC steel material is fixed by a fixing member in the recessed portion of the segment piece of the opposite ends of each side It is characterized in that the segment unit is Tightened the entire circumference by.

In the present invention, a substantially rectangular segment unit laid in a tunnel portion of an underpass tunnel having a substantially rectangular cross section and a substantially U-shaped segment unit laid in an approach portion open upward, A prestress is introduced between a plurality of segment pieces constituting each side by tensioning the PC steel material disposed in the box. Thereby, the bending rigidity of the segment piece is increased over the entire segment unit group constituting the substantially rectangular or substantially U shape, and even when the lining portion thickness of the segment piece is made thinner than before, it can sufficiently withstand the surrounding pressure. Strength can be secured.
Incidentally, PC steel, disposed in each side of the substantially rectangular or substantially U-shaped cross section, disposed on the inner peripheral surface side of the substantially rectangular cross section or a substantially U-shaped cross-section and the tensile stress is generated.
Thus, the whole of the segment piece group in the installation the PC steel in each side can prestressing.

In the present invention, for a segment unit having a substantially rectangular cross-section or a substantially U-shaped cross-section constituting the underpass tunnel, the bending rigidity of the segment unit is increased by arranging and tensioning the PC steel material in the segment piece group on each side. Therefore, even if the thickness of the lining portion of each segment piece is made thinner than that of the conventional segment piece, the strength can be ensured and the joint between segments becomes unnecessary, and the cost of the segment piece and the unit can be reduced.

Hereinafter, a segment unit according to an embodiment of the present invention will be described with reference to the accompanying drawings.
As shown in FIG. 1 (a), an underpass tunnel 2 that three-dimensionally intersects with a track, a road, or the like is a tunnel portion 2B constructed in the ground, and an approach portion that opens above the ground GL and the tunnel portion 2B. 2A. The end portion of the tunnel portion 2B following the approach portion 2A and the approach portion 2A is an inclined portion 2C. That is, a slope 2C having a downward slope that gradually increases in depth from the ground GL toward the ground is formed, becomes substantially horizontal at a predetermined depth, and further has an upward slope toward the ground at a predetermined point. 2C is formed.
The lining portion of the tunnel portion 2B is laid with a substantially rectangular segment ring 10 that is entirely embedded in the ground, and the lining portion of the approach portion 2A has a substantially U-shaped cross section that opens upward to the ground. The substantially U-shaped segment 20 which comprises the unit of this is laid (refer FIG.1 (b)).
In constructing the underpass tunnel 2, various well-known methods can be adopted, but in this embodiment, a substantially rectangular cross-section shield excavator (not shown) is used from the viewpoint of effective use of the cross section, reduction of construction period and construction cost. The substantially rectangular segment ring 10 and the U-shaped segment 20 are assembled behind the substantially rectangular cross-section shield excavator.

As shown in FIG. 2, the substantially rectangular segment ring 10 is composed of a plurality of segment pieces 11 and 12 arranged in the circumferential direction, and a PC steel wire penetrating the segment pieces 11 and 12 in the circumferential direction. 13 (PC steel). Specifically, a segment piece 12 having an L-shaped cross section is disposed at each corner portion of a substantially rectangular segment ring 10, and a block-shaped segment piece 11 is inserted between two L-shaped segment pieces 12, 12. It is arranged.
In the segment ring 10 having a rectangular cross section, at least the segment piece 11a on the upper side of the rectangular cross section among the block-shaped segment pieces 11 provided on each side is formed in a tapered shape having a trapezoidal plate shape. At the end of the assembly, it is inserted between the segment pieces 12, 12 having L-shaped cross sections on both sides to complete the assembly. The other block-shaped segment piece 11 may be a straight (or standard) block having a rectangular parallelepiped shape, but may be a tapered block similarly to the segment piece 11a.
The segment ring 10 having a rectangular cross section shown in FIG. 2 is configured by a block-shaped segment piece 11 being fitted between segment pieces 12 and 12 each having an L-shaped cross section, and arranged on each side. Prestress is introduced between the segment pieces 12 and 12 having a L-shaped cross section by a PC steel wire 13 having flexibility.
The PC steel wire 13 is arranged near the inner peripheral surface of the substantially rectangular ring, and the prestress introduced by the PC steel wire 13 cancels the tensile stress generated in the segment 10 and resists a large bending load. Can do.

The mounting structure of the PC steel wire 13 will be described. As shown in FIG. 2 and FIG. 3, a substantially box-shaped depression as a bolt box is formed on each inner peripheral surface side in the vicinity of both ends of the segment piece 12 having a substantially L-shaped cross section. A portion 12a is formed. The segment piece 12 having an L-shaped cross section is provided with a through hole 14 a extending from the recessed portion 12 a to the substantially L-shaped end surface, and the through hole 14 a is provided near the inner peripheral surface of the segment 12. Similarly, the block-shaped segment 11 has a through-hole 14b communicating between both ends close to the inner peripheral surface thereof.
In the segment ring 10 having a substantially rectangular cross section, the segment pieces 11, 12, 11 constituting each side are connected to each other, and are provided closer to the inner peripheral surface between the recessed portions 12 a, 12 a of the both side segment pieces 12, 12. The through holes 14a, 14b, and 14a communicate in a substantially straight line. A flexible PC steel wire 13 is inserted into the through holes 14a, 14b, and 14a from one side, and both ends of the PC steel wire 13 are fixed by the fixing tool 15 in the recessed portion 12a.

FIG. 4 shows a fixing tool 15 for the PC steel wire 13. A first fixing tool 15 </ b> A is fixed to one end of the PC steel wire 13. The other end portion of the PC steel wire 13 protrudes from the through hole 14a of the segment piece 12 having an L-shaped cross section, and the PC steel wire 13 is held by the second fixing tool 15B in a state of being tensioned using a center hole jack (not shown). Tighten up. As shown in FIG. 4A, the first fixing tool 15A is formed of a substantially cylindrical member, and is fixed by being locked to the inner surface of the cylindrical member with the PC steel wire 13 inserted through the inner hole. As shown in FIGS. 4 (a) and 4 (b), the second fixing tool 15B has a plurality (for example, four) of gaps between the PC steel wire 13 inserted into the tapered central hole of the sleeve 16 and the second fixing tool 15B. The PC steel wire 13 is fixed from the side by inserting the wedge-shaped grips 17.
FIG. 4 shows a one-side pulling structure in which one end of the PC steel wire 13 is fixed by the first fixing tool 15A, and the other end of the PC steel wire 13 is fixed by the second fixing tool 15B while being pulled by the center hole jack. ing.
Accordingly, the segment pieces 11, 12, 11 constituting each side can be prestressed and tightened. Thereafter, the recesses 12a and 12a are filled with concrete.
FIG. 5 shows a modification of the fixing tool 15. In this modification, there is provided a double-drawing structure in which both ends of the PC steel wire 13 are fixed by the second fixing tools 15B and 15B while being pulled by a center hole jack. Either the fixing tool 15 of the PC steel wire 13 may be employed as shown in FIGS.

  As described above, according to the segment ring 10 according to the present embodiment, the PC steel material 13 is disposed on the segment pieces 12, 11, 12 on each side of the segment unit 10 having a substantially rectangular cross section constituting the underpass tunnel and fixed. Tensioning with the tool 15 can increase the bending rigidity of the segment ring 10, so that the lining thickness of the segment pieces 11 and 12 can be made thinner than that of the conventional segment piece and an inter-segment joint is not required. The manufacturing cost of the segment pieces 11 and 12 can be reduced.

FIG. 6 shows a segment according to the second embodiment of the present invention.
In this embodiment, about the substantially L-shaped segment piece 12 and the block-shaped segment piece 11 which comprise the segment ring 10 'of a substantially rectangular cross section, the PC steel wire 13 is not provided for each side of the substantially rectangular cross section. A continuous PC steel wire 23 having flexibility is disposed over the entire circumference of the substantially rectangular ring.
In the segment ring 10 ′ having a substantially rectangular cross section shown in FIG. 6, one side, for example, on the inner peripheral surface side of both ends of the block-shaped segment piece 11 assembled at the center of the pieces 12, 11, 12 constituting the bottom side, respectively. A pair of recesses 11a and 11b constituting the bolt box are provided. Further, the through holes 14a, 14b, 14a are formed so as to communicate with each other in the plurality of blocks 12, 11, 12 constituting the sides of the substantially rectangular cross section, starting from one concave portion 11a and ending at the other concave portion 11b. Keep it.
Then, a PC steel wire 23 having one end fixed by a fixing tool 15, for example, a first fixing tool 15A, is inserted into the through-hole 14b from one recessed portion 11a, and the through-holes 14b, 14a of the blocks 11, 12,. And is pulled out from the through hole 11 of the other recessed portion 11b, and a prestress is introduced into the PC steel wire 23 using the center hole jack J on the other end side. And the other end side of PC steel wire 23 is fixed with the 2nd fixing tool 15B, for example. And the inside of each recessed part 11a, 11b is embedded with concrete.

  Also in the present embodiment, the segment piece 12, 11, 12,..., The entire segment piece 10 'having a substantially rectangular cross section is inserted into the segment pieces 12, 11, 12,. The whole circumference can be connected together and prestressed to increase the bending rigidity of the segment ring 10, and the lining thickness of the segment pieces 11 and 12 can be made thinner, reducing the manufacturing cost. can do.

Next, a tight structure using the PC steel wire 13 shown in the first embodiment can be employed for the substantially U-shaped segment 20 shown in FIG. This will be described as a third embodiment.
That is, the substantially U-shaped segment 20 having a substantially U-shaped cross section shown in FIG. 7 is a segment unit provided in the approach portion 2A, and is an outline in which the upper surface of the substantially rectangular segment ring 10 according to the first embodiment is opened. It is a configuration. That is, in the substantially U-shaped segment 20, approximately L-shaped segment pieces 22, 22 are arranged at the corners on both sides of the base, and the block-shaped segment piece 21 is inserted and inserted in the middle of the bottom, and the approximately L-shaped located on both sides The block segment pieces 21 and 21 are attached to the upper surface of the end portions of the segment pieces 22 and 22.
And, at the bottom side, the PC steel wire 13 is inserted through the through holes 14a and 14a and the through holes 14b of the block-shaped segment piece 21 from the recessed portions 22a and 22a provided in the L-shaped segment pieces 22 and 22 on both sides. For example, the first and second fixing tools 15A and 15B are tightened to give prestress. Similarly, on both sides, the PC steel wire 13 is inserted through the through hole 14a of the recessed portion 22a of the L-shaped segment piece 22 and the through hole 14b of the block-shaped segment piece 21, and the recessed portion provided in the L-shaped segment piece 22 is provided. Prestress is applied to the end portion of the PC steel wire 13 projecting to 22a and the recessed portion 21a provided in the block-shaped segment piece 21, and the ends are fastened by the fixing tools 15A and 15B.

Next, FIG. 8 shows a fourth embodiment of the present invention.
A substantially U-shaped segment 20 'according to the fourth embodiment shown in FIG. 8 is formed of a group of segment pieces 21, 22 having a configuration in which the upper side, that is, the upper part of the substantially rectangular segment ring 10' according to the second embodiment is opened. . The substantially U-shaped segment 20 that opens upward is provided with substantially L-shaped segments 22 and 22 at the corners on both sides, like the generally rectangular segment 10 'according to the second embodiment, and a block-shaped segment 21 in the middle of the bottom. And block-shaped segments 21 and 21 are attached to upper portions on both sides of the substantially L-shaped segments 22 and 22.
In the substantially U-shaped segment 20 ′, through holes 14 b and 14 a drilled in the segments 21 and 22 are connected in a substantially U-shape. A flexible PC steel wire 33 fixed by the first fixing tool 15A described above is passed through a through hole from a recessed portion 21b provided on the end face of the block-shaped segment 21 which is one end of the substantially U-shaped segment 20 '. 14b, inserted into the through-holes 14b, 14a of the segments 21, 22 in sequence, into a string-like shape and pulled out from the recess 21b formed on the end face of the other block-shaped segment 21, the center hole jack In J, prestress is introduced into the other end of the PC steel wire 33, and the second fixing tool 15B described above is used to fasten. Thereby, the plurality of segment pieces 21, 22,... Having a substantially U-shaped cross section can be integrally connected by the string-like PC steel wire 33 to give prestress. The fixing device 15 may use, for example, a double pulling structure shown in FIG.

The pre-stress is applied by arranging the PC steel materials 23 and 33 over the entire circumference or all sides of the substantially rectangular segment ring 10 'and the substantially U-shaped segment 20' according to the second and fourth embodiments described above. I made it.
However, also in these substantially rectangular segment rings 10 'and U-shaped segments 20', the flexible PC steel wires 13, 23, 33 are substantially rectangular or substantially similar to the first and third embodiments. A pre-stress may be applied to each side by dividing the U-shaped section into each side and inserting the segments into the through holes 14a, 14b between the segment pieces 12, 12, 22, 22 or 21, respectively. .
Also in these cases, it is preferable that the substantially rectangular segment ring 10 'and the substantially U-shaped segment 20' are arranged near the inner peripheral surface of the substantially rectangular or substantially U-shaped cross section where tensile stress is generated.

Each of the segment pieces 11, 12, 21, and 22 may be a steel segment, a reinforced concrete segment, or a concrete-filled steel segment.
Further, in each of the above-described embodiments, the through holes 14a and 14b are provided in the segment piece, but instead of the through hole, a groove portion is formed by cutting away from the inner surface of each segment piece in the outer surface direction, and the PC steel wire 13, After arrange | positioning 23 and 33, you may fill a groove part with concrete. In this case, the PC steel wire 13 may be a non-flexible PC steel rod. The PC steel wires 13, 23, 33, PC steel bars, etc. constitute PC steel.
Further, in each of the above-described embodiments, the substantially rectangular segment ring 10, 10 ′ formed by the plurality of segment pieces 11, 12, 21, 22 and the substantially U-shaped segment 20, 20 ′ constitute a segment unit. .

(A) is the schematic of an underpass tunnel, (b) is a sectional side view of an approach part. It is sectional drawing which shows the substantially rectangular segment ring by 1st embodiment of this invention. It is an expanded sectional view of the upper side part of the substantially rectangular segment ring shown in FIG. The fixing tool which fixes PC steel wire to the recessed part of a segment is shown, (a) is a sectional side view, (b) is an end view of the second fixing tool. It is a sectional side view which shows the modification of a fixing tool. It is sectional drawing which shows the substantially rectangular segment ring by 2nd embodiment of this invention. It is sectional drawing which shows the substantially U-shaped segment by 3rd embodiment of this invention. It is sectional drawing which shows the substantially U-shaped segment by 4th embodiment of this invention. It is a figure which shows the conventional substantially rectangular segment ring provided in a tunnel part, (a) is a figure which shows the pressure which acts on a segment ring, (b) is the state deform | transformed by the pressure which acts on each side of a substantially rectangular segment ring. FIG. It is a figure which shows the conventional substantially U-shaped segment provided in an approach part, (a) is a figure which shows the pressure which acts on a substantially U-shaped segment, (b) is the figure which showed the state deform | transformed with the pressure which acts on a side surface, (C) is the figure which showed the state which deform | transformed with the pressure which acts on a bottom face.

Explanation of symbols

2 Underpass tunnel 2A Approach portion 2B Tunnel portion 2C Inclined portion 10, 10 'Approximately rectangular segment ring 20, 20' Approximately U-shaped segment 11, 21 Block-shaped segment piece 12, 22 Approximately L-shaped segment piece 11a, 11b, 12a, 21a, 22a Concave portion 13, 23, 33 PC steel wire (PC steel)
14a, 14b Through hole 15 Fixing tool 15A First fixing tool 15B Second fixing tool 16 Sleeve 17 Grip

Claims (1)

A substantially rectangular shape consisting of a plurality of segment pieces arranged in the circumferential direction or a substantially U-shaped segment unit opened upward ,
A substantially box-shaped recessed portion is formed on each inner peripheral surface side of the segment pieces at both ends of the plurality of segment pieces constituting each side of the segment unit ,
PC steel material is disposed in a plurality of segment pieces constituting each side of the segment unit, and the PC steel material is disposed closer to the inner peripheral surface than the center in the thickness direction of the plurality of segment pieces,
Wherein is Tightened via the PC steel material through the plurality of segment pieces adjacent in each side in the circumferential direction, both ends of the PC steel material by the fixing member in the recessed portion of the segment piece of the opposite ends of each side A segment unit, wherein the segment unit is fastened to the entire periphery by being fixed.

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