JP3980222B2 - Flexible segment joining structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a joining structure of flexible segments constituting an annular support body of a tunnel, and more particularly, to a joining structure of flexible segments so as to improve water stoppage at a joining portion in a circumferential direction of the tunnel.
[0002]
[Prior art]
In general, in tunnel excavation work, when a tunnel is dug by a shield machine, an annular support composed of a plurality of segments is sequentially assembled along the tunnel inner surface so as to support the tunnel inner surface. I have to.
[0003]
Also, when the surrounding ground fluctuates due to unequal subsidence or earthquake motion, it is necessary to displace the tunnel following the deformation. Therefore, an annular support made of a flexible segment is inserted into a portion where a large displacement of the tunnel is assumed, and the flexible segment absorbs displacement such as twisting or shearing deformation of the tunnel.
[0004]
The flexible segment has a structure in which a rubber block is interposed between a pair of steel frame segments, and the rubber block is in close contact with the frame segment by means such as vulcanization and bolting. .
[0005]
Although the flexible segment configured as described above can absorb the displacement of the tunnel due to deformation of the rubber block, if the rubber block is greatly deformed, the surface pressure at the bonding surface in the circumferential direction of the tunnel is reduced. Even if a water-stopping material is interposed, there is a risk of water leakage. Therefore, in the conventional flexible segment, the rubber block joint surface is formed on the joint surface of the rubber block by projecting in the circumferential direction of the tunnel, or the rubber block is compressed between the frame segments before construction. Bulges in the tunnel circumferential direction.
[0006]
However, if the joint surface of the rubber block is simply protruded as described above, the water-stopping effect cannot be significantly improved. In addition, if the protruding amount of the rubber block joint surface is increased, the water stoppage can be improved. However, if this protrusion amount is increased, the rubber block joint surface and the water stop material placed on the joint surface will be damaged during construction. In addition, when the final flexible segment for completing the annular support is inserted, the projecting portion of the joint surface interferes with the construction work.
[0007]
[Problems to be solved by the invention]
An object of the present invention is to provide a flexible segment joining structure that can improve the water-stopping property at a segment joint in the circumferential direction of the tunnel.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the flexible segment joining structure of the present invention comprises a plurality of flexible segments having a rubber block interposed between a pair of frame segments formed in an arc shape in the circumferential direction of the tunnel. In the joining structure of the flexible segments that are connected to form an annular support, protrusions that intersect while extending in a diagonal direction are arranged on the joining surface in the tunnel circumferential direction of the rubber block. .
[0009]
The present inventors obtained the surface pressure distribution on the joint surface in the circumferential direction of the tunnel with shear deformation applied to the rubber blocks between the frame segments by FEM analysis. It has been found that it tends to cause a drop and easily leaks along its diagonal.
[0010]
Therefore, as described above, by disposing the protruding ridges that extend in the diagonal direction on the joint surface in the tunnel circumferential direction of the rubber block, it is possible to greatly improve the water stoppage at the segment joint portion in the tunnel circumferential direction. it can. Moreover, since the said protrusion effectively compensates the surface pressure fall in a joint surface, it becomes possible to make the amount of protrusion small and to perform the construction work of a flexible segment easily.
[0011]
On the other hand, another flexible segment joining structure of the present invention is formed by connecting a plurality of flexible segments with rubber blocks interposed between a pair of frame segments formed in an arc shape in the tunnel circumferential direction. In the joining structure of the flexible segments constituting the annular support, the adjacent flexible segments are coupled to each other via a staple-like connector having at least one end inserted into the rubber block. Is.
[0012]
By joining adjacent flexible segments to each other through the staple-like connector having at least one end inserted into the rubber block in this way, the contact surface pressure of the adjacent rubber blocks is increased, so that the segment joining in the circumferential direction of the tunnel It is possible to greatly improve the water stoppage at the part. Further, since the contact surface pressure of the rubber block is increased by the staple-like connecting tool, it is possible to reduce the projecting amount of the joining surface at the time of construction and easily perform the construction work of the flexible segment.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.
[0014]
FIG. 1 illustrates a tunnel structure provided with an annular support. As shown in FIG. 1, in excavation work of a tunnel, when a tunnel is dug by a shield excavator, an annular support R ′ composed of a plurality of rigid segments S ′ is arranged in the tunnel excavation direction along the tunnel inner surface. The tunnel inner surface is supported by assembling sequentially. An annular support R made of a flexible segment S is inserted along the inner surface of the tunnel into a portion where a large displacement of the tunnel is assumed, and the flexible segment S can cause twisting or shear deformation of the tunnel. Absorbs displacement.
[0015]
FIG. 2 illustrates a flexible segment. As shown in FIG. 2, the flexible segment S has a rubber block 2 interposed between a pair of steel frame segments 1, 1 formed in an arc shape, and the rubber block 2 is attached to the frame segment 1. On the other hand, it has a structure in which it is brought into close contact by means such as vulcanization and bolting. The frame segment 1 has an inner plate 1a and an outer plate 1b, and a plurality of girders 1c are provided between the inner plate 1a and the outer plate 1b.
[0016]
The flexible segment S is provided with a plurality of thrust rods 3 extending in the tunnel axis direction while penetrating the inner plate 1a and the rubber block 2 of the frame segment 1. By inserting the rod receiving member 4 between the end of the thrust rod 3 and the outer plate 1b of the frame segment 1, these thrust rods 3 support the thrust of the shield machine. On the other hand, when the rod receiving member 4 is not attached, the mutual interval between the frame segments 1 and 1 is variable. Further, a nut 5 is extrapolated to the thrust rod 3, and the nut 5 is tightened to a male thread portion provided on the outer peripheral surface of the thrust rod 3, thereby compressing the rubber block 2 by narrowing the mutual interval between the frame segments 1, 1. It is designed to hold the state.
[0017]
FIGS. 3A and 3B show a connecting structure of flexible segments according to the first embodiment of the present invention. In this embodiment, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof is omitted.
[0018]
As shown in FIGS. 3 (a) and 3 (b), on the joining surface in the circumferential direction of the tunnel of the rubber block 2, the protruding ridges 6 that intersect with each other while extending in the diagonal direction are integrally formed. The protrusion 6 may be provided on one joining surface of the rubber block 2 or may be provided on both joining surfaces. That is, it is only necessary that at least one cross-shaped protrusion 6 exists between the rubber blocks 2 and 2 in the connecting structure of the adjacent flexible segments S and S.
[0019]
Further, as shown in FIGS. 4A and 4B, the protrusion 6 may be formed separately from the rubber block 2. In this case, the protrusion 6 does not necessarily need to be made of a rubber composition, and may be made of a water stop material made of a water absorbent resin or the like. When the ridge 6 is separated from the rubber block 2, a concave portion that matches the planar shape of the ridge 6 and is shallower than the height of the ridge 6 is provided on the joint surface of the rubber block 2. 6 should be fitted. By fitting the protrusion 6 into the joint surface of the rubber block 2 as described above, the workability of the flexible segment S is not hindered even when the protrusion 6 separate from the rubber block 2 is used.
[0020]
Further, the protrusion 6 may be divided into a portion extending along one diagonal line of the joint surface of the rubber block 2 and a portion extending along the other diagonal line. Also in this case, the split piece of the protrusion 6 may be formed integrally with the rubber block 2 or may be formed separately from the rubber block 2.
[0021]
The cross-sectional shape of the protrusion 6 is not particularly limited, and can be various shapes. For example, as shown in FIGS. 5A to 5D, the cross-sectional shape of the protrusion 6 can be a triangle, a trapezoid, a rectangle, or a bowl shape with a smooth top surface of the rectangle.
[0022]
FIG. 6 shows the surface pressure distribution at the joint surface in the circumferential direction of the tunnel when the rubber block 2 between the frame segments 1 and 1 is subjected to shear deformation in the case where no protrusion 6 is provided on the joint surface of the rubber block 2. The result obtained by analysis is shown. However, in the figure, the darker the dots, the higher the pressure. As can be seen from FIG. 6, since the surface pressure is reduced at the diagonal portion of the joint surface of the rubber block 2 during shear deformation, water leakage is likely to occur along the diagonal line X. In addition, when shear deformation in the direction opposite to the figure is given, water leakage is likely to occur along the diagonal line intersecting the diagonal line X.
[0023]
In the flexible segment joining structure according to the above-described embodiment, the protrusion 6 intersects the joint surface of the rubber block 2 in the tunnel circumferential direction while extending diagonally, so that the protrusion 6 is a surface on the joint surface. Since the pressure drop is effectively compensated for, the water stoppage at the junction of the flexible segment S in the tunnel circumferential direction can be improved as compared with the conventional case.
[0024]
Moreover, since the protrusion 6 effectively compensates for the decrease in surface pressure at the joint surface, the protrusion amount can be reduced. Therefore, when the last flexible segment S for completing the annular support R is inserted, the protrusion 6 on the joining surface hardly interferes, so that the construction work of the flexible segment S can be easily performed. . The height of the protrusion 6 from the joint surface is preferably in the range of 3 to 20 mm. If this height is less than 3 mm, the effect of improving the water-stopping property becomes insufficient, and conversely if it exceeds 20 mm, the construction work becomes difficult.
[0025]
FIG. 7 shows a connecting structure of flexible segments according to the second embodiment of the present invention. In this embodiment, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof is omitted.
[0026]
As shown in FIG. 7, a plurality of staple insertion holes 7 are provided at the ends of the rubber block 2 in the circumferential direction of the tunnel. As the staple-like coupler 8 for inserting into the staple insertion hole 7, those shown in FIGS. 9A to 9D can be used. That is, the staple connector 8 has a structure in which both end portions 8b and 8b are bent in the same direction with respect to the intermediate portion 8a. As the material of the staple-like connector 8, a highly elastic material such as a steel wire having a higher elastic modulus than the rubber block 2 can be used. The intermediate portion 8a can be formed into various shapes, and the elastic force of the staple-like coupler 8 can be arbitrarily set based on the shape.
[0027]
Before construction, the rubber block 2 is in an uncompressed state. The rubber block 2 has a thickness T ₁ before construction, and is designed so that the joint surface in the circumferential direction of the tunnel does not protrude from the end surface of the flexible segment S in an uncompressed state.
[0028]
When constructing the flexible segment S, first, as shown in FIG. 7, the annular support R is formed by connecting the flexible segment S in the tunnel circumferential direction with the rubber block 2 in an uncompressed state. Then, as shown in FIG. 8, a rubber block 2 is in a compressed state by tightening the nut 5, its thickness and T _2. At this time, although the pressure at the joint surface between the adjacent rubber blocks 2 and 2 increases, if the tunnel is greatly displaced after construction and a tensile force acts in the tunnel axis direction, the tensile force cannot be resisted.
[0029]
Therefore, the adjacent flexible segments S, S are connected to each other by using the staple-like connector 8, and the adhesion between the adjacent rubber blocks 2, 2 is reinforced in advance. This reinforcement can be performed in various forms as shown in FIGS. In FIG. 10, both ends 8b and 8b of the staple-like connector 8 are inserted into adjacent rubber blocks 2 and 2, respectively. In FIG. 11, the staple-like connector 8 has one end 8 b inserted into the rubber block 2 and the other end 8 b attached to the frame segment 1.
[0030]
In FIG. 12, the staple-like coupler 8 has one end 8b inserted into the rubber block 2 and the other end 8b attached to the frame segment 1, and between the adjacent flexible segments S, S. A staple-like connector 8 is overlaid. Thus, when adjoining flexible segments S and S are combined via the staple-like connector 8, at least one end 8b of the staple-like connector 8 may be inserted into the rubber block 2.
[0031]
When attaching the staple-like connector 8 made of a highly elastic material, both ends 8b, 8b of the staple-like connector 8 are attached to the adjacent flexible segments S, S in an expanded state. It is preferable to increase the contact surface pressure between the adjacent rubber blocks 2 and 2 based on the restoring force. Thus, by utilizing the restoring force of the staple-like coupler 8 made of a highly elastic material, the contact pressure between the adjacent rubber blocks 2 and 2 can be further improved.
[0032]
In the tunnel excavation work shown in FIG. 1, the annular support R made of the flexible segment S is assembled between the annular support R ′ made of the rigid segment S ′, and the thrust of the shield machine advances the flexible segment. After being stabilized to the extent that it is not transmitted to S, the nut 5 of the thrust rod 3 is loosened so as to allow the deformation of the rubber block 2 in the compressed state to complete the construction. After the construction, the rubber block 2 maintains a predetermined compression amount, and expands so as to absorb the displacement when the displacement occurs in the tunnel.
[0033]
In the flexible segment connecting structure according to the above embodiment, the adjacent flexible segments S and S are coupled to each other via the staple-like connecting tool 8 having at least one end 8b inserted into the rubber block 2. Since the contact surface pressure between the adjacent rubber blocks 2 and 2 is increased, the water stoppage at the junction of the flexible segment S in the tunnel circumferential direction can be improved as compared with the conventional case. In particular, even if a tensile force in the tunnel axis direction acts due to an earthquake or the like after construction, the tensile force can be resisted by the restoring force of the staple-like connector 8. In addition, since the surface pressure of the rubber block 2 is obtained by the mechanical action of the staple-like connector 8, there is very little change in the surface pressure distribution over time.
[0034]
Further, since the contact surface pressure of the rubber block 2 is increased by the staple-like connector 8, a convex portion is provided on the joint surface of the rubber block 2, or the rubber block 2 is compressed during construction so that the joint surface is in the tunnel circumferential direction. There is no need to bulge. Therefore, the last flexible segment S for completing the annular support R can be easily inserted. Moreover, since the joint surface of the rubber block 2 is not rubbed when the flexible segment S is inserted, the water stop material arranged on the joint surface does not peel off during construction.
[0035]
【The invention's effect】
As described above, according to the present invention, a plurality of flexible segments having rubber blocks interposed between a pair of frame segments formed in an arc shape are connected in the circumferential direction of the tunnel to form an annular support. In the flexible segment joining structure, the protruding ridges intersecting while extending in the diagonal direction are arranged on the joint surface in the circumferential direction of the tunnel of the rubber block, or adjacent flexible segments are connected via a staple-like connector. By being coupled to each other, the water stoppage at the segment joint portion in the tunnel circumferential direction can be improved.
Further, according to the present invention, it is possible to reduce the protruding amount of the rubber block joint surface at the time of construction, and to easily perform the construction work of the flexible segment.
[Brief description of the drawings]
FIG. 1 is a partially cutaway perspective view illustrating a tunnel structure provided with an annular support.
FIG. 2 is a perspective view illustrating a flexible segment.
FIGS. 3A and 3B show a connecting structure of flexible segments according to the first embodiment of the present invention, wherein FIG. 3A is a plan view and FIG. 3B is a side view.
4A and 4B show a modification of the connecting structure of flexible segments according to the first embodiment of the present invention, where FIG. 4A is a plan view and FIG. 4B is a side view.
FIGS. 5A and 5B show protrusions used in the first embodiment of the present invention, and FIGS.
FIG. 6 is a pressure distribution showing a result obtained by FEM analysis of a surface pressure distribution on the joint surface in the circumferential direction of the tunnel when shear deformation is applied to the rubber block when no protrusion is provided on the joint surface of the rubber block. FIG.
FIG. 7 is a cross-sectional view showing a flexible segment connecting structure (before construction) according to a second embodiment of the present invention.
FIG. 8 is a cross-sectional view showing a flexible segment connecting structure (after construction) according to a second embodiment of the present invention.
FIG. 9 shows various staple-like couplers used in the second embodiment of the present invention, and (a) to (d) are perspective views, respectively.
FIG. 10 is a cross-sectional view showing a flexible segment connecting structure (after reinforcement) according to a second embodiment of the present invention.
FIG. 11 is a cross-sectional view showing a modification of the flexible segment connecting structure (after reinforcement) according to the second embodiment of the present invention.
FIG. 12 is a cross-sectional view showing a further modification of the flexible segment connecting structure (after reinforcement) according to the second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Frame segment 2 Rubber block 3 Thrust rod 4 Rod receiving member 5 Nut 6 Projection 7 Staple insertion hole 8 Staple-like connection tool S Flexible segment R Annular support

Claims (5)

In the joint structure of flexible segments, in which a plurality of flexible segments having rubber blocks interposed between a pair of frame segments formed in an arc shape are connected in the circumferential direction of the tunnel to constitute an annular support. A flexible segment joint structure in which protrusions that intersect while extending in a diagonal direction are arranged on a joint surface in a circumferential direction of a tunnel of a rubber block. The flexible segment joining structure according to claim 1, wherein the protrusion is integrally formed on a joining surface of the rubber block. The flexible segment joining structure according to claim 1, wherein the protrusion is formed separately from the rubber block. In the joining structure of the flexible segments, in which a plurality of flexible segments with rubber blocks interposed between a pair of frame segments formed in an arc shape are connected in the circumferential direction of the tunnel to form an annular support body. A joining structure of flexible segments in which adjacent flexible segments are coupled to each other via a staple-like connector having one end inserted into the rubber block. The staple-like connector is made of a highly elastic material, attached to adjacent flexible segments in a state where both ends of the staple-like connector are spread out, and adjacent rubber blocks based on the restoring force of the staple-like connector The joint structure of the flexible segment according to claim 4, wherein the contact surface pressure is increased.

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