JP5378673B2 - Segment connection structure and tunnel - Google Patents

Description

  The present invention relates to a connection structure in a segment joint and a tunnel that can be provided with the connection structure of the segment.

  When constructing a tunnel in the ground, the ground occupancy problem due to the open-cut method is eliminated, and even when the target ground is soft, efficient construction is possible in the shortest possible construction period. As a construction technique that enables tunnel construction, the shield method is generally known. In this shield method, tunnels with various cross-sectional shapes such as circular, elliptical, square, rectangular, etc. are constructed, and multiple segments are arranged in the circumferential direction or the contour direction of the tunnel cross-section in the element device in the shield machine. A shield tunnel having a desired cross-sectional shape and extension is constructed by assembling endlessly and sequentially assembling them in the tunnel axial direction. The specifications of this segment are appropriately selected from the cost, design conditions, etc., such as those made of reinforced concrete, those composed of a composite structure of steel shell and concrete, and those made of steel.

  For example, in the circumferential segment joint (generally, the joint between the circumferential segments is referred to as a segment joint, and the joint between the axial segments is referred to as a ring joint), the segments can rotate relative to each other. There is a deformation such as an opening between the segments due to this rotational action. Due to the rotational action of the segment joint, the rigidity of the joint portion must be lower than the rigidity of the segment itself.

  However, in the design (analysis) of the segment ring cross section in the shield tunnel, (1) a method of designing the segment ring on the assumption that the bending rigidity is uniform, and (2) assuming that the segment ring is a multi-hinge ring. There are a method of designing, (3) a method of designing as a segment ring with a rotating spring against a bending moment, and (4) a method of having a rotating spring and evaluating the splicing effect by staggered arrangement with a shear spring. One of the design methods is adopted according to various conditions, and the design of the segment ring is executed. Here, in the above method (1), the effective rate of bending stiffness: η (η ≦ 1) and the bending moment amplification factor: ζ (0 ≦ ζ ≦ 1) are introduced into the design. There is a problem that it is difficult to accurately evaluate η and ζ based on various conditions such as conditions and the joint structure of the segment, and as a result, the design must be a safe side. In the method (2) described above, since this method expects a wide range of reaction forces in the ground surrounding the tunnel, it is necessary to pay close attention to the selection of the applicable ground. If it cannot be expected, the shape of the segment ring must be maintained while making adjustments such as providing auxiliary means for self-sustaining the segment ring or giving some rigidity to the segment joint. Further, in the methods (3) and (4) described above, it is necessary to appropriately set the rotational spring constant for evaluating the segment joint portion according to the type of the segment and the joint structure. There is a problem that it takes experience and it takes a lot of time to set an optimal spring constant. As mentioned above, considering the fact that the segment joint actually rotates and that it is desirable to avoid the design of the safety side as much as possible from the reduction of construction costs, setting the rotation spring However, it is considered preferable to adopt the design methods (3) and (4).

  In the current segment ring design, the rotation of the segment joint is taken into consideration as described above, but it is possible if the problem that the setting of the rotary spring is not easy and the credibility of the analysis result are considered together. It is desirable to be able to propose a connection structure for segment joints that is simple and free of rotation as much as possible. Patent Document 1 can be cited as a conventional technique related to the structure of the segment joint portion. This is related to the joint of the segment of the composite structure in which the inner and outer surfaces of the concrete block are covered with steel plates, and the steel plate ends outside both segments are formed in a comb-like shape so that they can mesh with each other, and formed in a meshing posture. A long bolt with a circular cross section is inserted into and connected to a bolt hole with a circular cross section.

  In this segment joint, it is indispensable to provide steel plates on the inner and outer surfaces of the segment, and the application range is extremely limited, for example, it cannot be applied to a segment made only of reinforced concrete.

  On the other hand, regarding the rotation of the segment joint part, for example, in the event of a fire in the tunnel, the outside of the joint part (the ground side) opens, and the inside of the joint part (the inside of the tunnel side) presses each other due to this. Both segments are prompted to rotate in the direction. Specifically, based on FIG. 15, in an actual tunnel, a bending moment as shown in the figure is generated, for example, in the circumferential ring cross section due to the action of earth pressure. In the design stage, a bending moment such as a dotted line in the figure is generated by loading the upper earth pressure P1, the ground reaction force P2 from the lower side, and the side earth pressure P3 on the ring cross section, and this bending moment can be resisted. A cross-sectional structure is set. Here, the moment region protruding to the outside of the ring can be a negative bending region (-region in the figure), and the moment region in the ring can be a positive bending region (+ region in the figure).

  As shown in the figure, there is often a case where a segment joint portion exists in this negative bending region. However, if a fire in the tunnel occurs as described above, the segment joint portion in this negative bending region is shown in FIG. It has been specified by the inventor's experiment that it deforms like this. In the same figure, in the outer area Q1 (ground side area) of each segment S, S, both are warped outside, and in the inner area Q2 (inside tunnel inner area) of the segment joint portion, the segments S, S are opposite to each other. Rotation that presses (compresses) each other works. Due to this rotating action, there is a risk that the segment of the inner region Q2 may be crushed in some cases, and a void generated in the outer region Q1 is added to this, and the water-stopping property of the tunnel is also impaired. For this reason, it is important to construct a tunnel with a joint structure in which the rotation of the segment joint part is suppressed, and it is possible to avoid damage to the tunnel even in the event of a fire in the tunnel. It will lead to securing.

Japanese Patent Laid-Open No. 9-4390

  The present invention has been made in view of the above problems, and provides a segment connection structure capable of effectively suppressing the rotation of the segment at the segment joint portion with a simple configuration, and a tunnel including the same. The purpose is to do.

In order to achieve the above-mentioned object, the segment connection structure according to the present invention comprises:
In the connection structure of the segments that constitute the tunnel by being connected in the circumferential direction and the axial direction in the borehole,
In the segment, both end portions forming a segment joint are formed in a stepped shape including a convex portion and a concave portion in the circumferential direction, and the convex portion is formed with one or a plurality of axial through holes having a polygonal cross section. In addition, in a posture in which the convex portion of one segment is fitted into the concave portion of the other segment, a communication hole in which both the through holes communicate in the axial direction is formed, and both ends projecting from the shaft member are fitted. Concave grooves are formed at positions corresponding to the respective shaft members,
It said segments, in the convex portion of one segment is fitted in the recess of the other segment position, the shaft member of the cross-sectional dimension in the communication hole having the same shape is inserted before Killen hole,
Connection structure in the plurality the segments of being connected circumferentially endless segment joint segment unit Ru is formed is formed,
Aitonaru the segment unit, the together when the segment joint are connected in a posture mutually offset, the both ends of both end faces of the joint of any segment units before Kishotonariru segment unit wherein a plurality of shaft members projecting in the axial direction of the segments, is fitted to the mutually corresponding the groove formed on the end face of the other segment units,
A connection structure is formed in a ring joint in which segment rings are connected in the tunnel axis direction to construct a tunnel .

  The segment to which the present invention is directed is made of at least concrete such as a reinforced concrete segment or a composite structure of steel shell and concrete. This segment may be a fire-resistant segment having fire-resistant performance. In this case, a segment in which organic fibers such as olefin fiber and polypropylene fiber are mixed in general concrete, and high heat resistance such as alumina cement. It is possible to use a segment made of concrete made of high thermal insulation aggregate such as cement and massive slag. Furthermore, in order to increase the rigidity of the segment and prevent surface peeling during a fire, steel fibers or carbon fibers may be mixed.

  The tunnel (shielded tunnel) having the segment connection structure of the present invention has various cross-sectional shapes such as a tunnel having a circular or substantially elliptical cross section and a square or a horizontally or vertically long cross section. . For example, in the case of a tunnel having a circular or elliptical tunnel cross section, a segment having a predetermined curvature and a rectangular shape that is long in the circumferential direction when a wide surface is viewed in plan can be used. Further, in the case of a tunnel having a rectangular cross section, a U-shaped segment is used at the corner, and a segment having a rectangular cross section is used at other general sites.

The segment used in the segment of the present invention has a connected end formed in a single step consisting of a convex part and a concave part. Further, a side surface of the convex part has a polygonal cross section. Is formed. The convex part of one segment end part to be connected is fitted into the concave part of the other segment end part, and in this fitting posture, both through holes communicate with each other to form a communication hole. A shaft member having the same shape as the communication hole or through hole and having the same cross-sectional dimension is inserted into the communication hole to form a connection structure.

  Here, the shaft member described above is a member having a required tensile strength or shear strength, such as steel or high-strength concrete reinforced with carbon fiber or steel fiber.

  The polygonal shape of the cross-sectional shape of the communication hole is a shape such as a triangle, a quadrangle (square, rectangle), or a pentagon or more, and an arbitrary shape having a plurality of corners can be selected. By inserting a shaft member having the same cross-section and the same size into the polygonal cross-section communication hole, there may be one or a plurality of combinations of the communication hole and the shaft member. Even in such a case, since the shape of the shaft member and the communication hole is a polygonal shape having a corner, rotation of the segments can be effectively suppressed.

  As described above, in a segment joint where a negative bending moment is always generated, in the event of a fire in the tunnel, the side of the joint inside the tunnel that is on the inner side of the tunnel will warp outward and a compressive force is applied. To do. However, since the rotation of the joint portion is suppressed by the connection structure described above, deformation due to warping is prevented, and as a result, the pressing action between the segments is reduced as much as possible. It leads to prevention. Furthermore, since this connection structure is a very simple structure, the manufacturing cost of the segment is not greatly increased.

  As another embodiment of the refractory segment according to the present invention, at least two through holes having a circular cross section are formed on the sides of both convex portions, and the end portions of both segments are fitted. The corresponding through-holes communicate with each other in the posture to form two or more communication holes, and shaft members having the same shape and the same cross-sectional dimensions as the communication holes are respectively inserted into the two or more communication holes. There may be.

  When the cross section of the communication hole is circular, the rotation of the segments cannot be suppressed at the segment joint portion by using only one of them. Therefore, when the cross section of the communication hole is circular, two or more communication holes are provided at intervals, and a shaft member having the same cross section and the same dimensions is inserted into each communication hole. In addition, that the cross section here is circular means that it includes a substantially circular shape such as an ellipse in addition to the circular shape.

  Furthermore, in another embodiment of the segment connection structure according to the present invention, an endless segment unit is formed by connecting a plurality of segments in a posture having the connection structure in the circumferential direction, and the axial direction The two segment units to be connected are connected in a posture in which the connection structures are shifted from each other, and the tip of the shaft member forming the connection structure of one segment unit is connected to the other segment unit Is fitted in a concave groove formed on the end face of the segment forming the.

  In this embodiment, in addition to the segment connection structure related to the segment joint, the segment connection structure related to the ring joint is also defined. For example, in the case of a tunnel with a circular cross section, a plurality of segments are assembled in an endless ring shape in the circumferential direction to form a ring-shaped segment unit, and this segment unit is connected in the axial direction of the tunnel, thereby extending a predetermined extension. A tunnel is formed. Here, the connection between the segment units in the axial direction is performed in a posture in which the connection structures of the segment joints forming the segment units are alternately shifted. Here, both ends of the shaft member forming the connection structure in the segment joint project from the corresponding communication hole and project from the end surface of the segment unit. On the other hand, in adjacent segment units, a concave groove into which the tip of this shaft member is fitted is formed at a position corresponding to each shaft member, and a plurality of shaft members protruding from the end surface of one segment unit are the other. The connection structure in the ring joint is formed by fitting into the corresponding concave groove formed on the end face of the segment unit.

  According to the present embodiment, it is possible to construct a connection structure in a ring joint by using a shaft member that forms a connection structure in a segment joint, and with a simple structure, efficiently in the circumferential direction and the axial direction. It is possible to construct a tunnel in which the rotation between segments is constrained.

By constructing a tunnel having the above-described segment connection structure, rotation is suppressed particularly in the segment joint portion, and therefore a tunnel composed of a segment ring having high rigidity can be constructed. Since the rotation is reliably restrained, it is possible to execute the segment ring design without adjusting the effective rate of bending rigidity, the amplification factor of the bending moment, or the rotation spring in the design stage. Become. Furthermore, since this connection structure has a simple configuration, the construction cost does not increase.

  As can be understood from the above description, according to the segment connection structure of the present invention, the rotation of the segment at least at the segment joint can be effectively suppressed with a very simple structure, and the design of the segment ring is simplified. This makes it possible to construct a highly rigid tunnel at a low cost.

  Embodiments of the present invention will be described below with reference to the drawings. 1 is a perspective view showing a tunnel having the segment connection structure of the present invention, and FIG. 2 is an exploded perspective view of two segments and a shaft member constituting the segment connection structure of the present invention. FIG. 3 is a perspective view of an embodiment of a segment connection structure constituted by two segments and a shaft member shown in FIG. 2. 4 and 5 are perspective views of other embodiments of the segment connection structure, respectively. The illustrated embodiment shows a connection structure of a tunnel having a circular cross section and a segment constituting the tunnel. However, a tunnel having an elliptical cross section, a square cross section, a rectangular cross section, and a segment having a shape adapted to the construction thereof is shown. Of course, it may be a connection structure.

  FIG. 1 shows that a plurality of segments 10 having a predetermined width and formed with a predetermined curvature are assembled in the circumferential direction (R direction in the figure) and assembled in the axial direction of the tunnel (A direction in the figure). The shield tunnel T constructed | assembled is shown. On the air side I in the tunnel, structures for various pipelines such as underground passages, subway lines, electricity and gas are constructed.

  FIG. 2 is an exploded perspective view of two segments and a shaft member constituting the segment connection structure of the present invention. The segment 10 is a reinforced concrete segment made of general concrete, but may be a segment made of a composite structure of concrete and steel. The segment 10 is made of a material in which organic fibers such as olefin fibers and polypropylene fibers are mixed in concrete, or a concrete made of high heat-resistant cement such as alumina cement and highly heat-insulating aggregate such as massive slag. It may be a refractory segment made as When the segment 10 is assembled in the circumferential direction, one convex portion 11 and one concave portion 12 are formed in a step shape at an end portion that connects to another adjacent segment 10, that is, an end portion that forms a segment joint. ing.

  As shown in the figure, a through-hole 13 that penetrates the convex portion 11 is formed on the side surface of the convex portion 11 formed at both ends of the segment 10, and the cross-sectional shape of the through-hole 13 is rectangular. Yes.

  As shown in the drawing, by fitting the convex portion 11 of one segment 10 adjacent in the circumferential direction to the concave portion 12 of the other segment 10, the through holes 13, 13 formed in both the convex portions 11, 11 communicate with each other. Thus, a communication hole is formed.

  A segment connection structure 30 shown in FIG. 3 is formed by inserting a shaft member 20 made of steel or concrete having the same cross-sectional shape and the same dimensions as the communication hole into the communication hole.

  This connection structure 30 is formed at each segment joint in the circumferential direction of the segment tunnel to form a segment ring, and this segment ring is connected via the ring joint in the tunnel axis direction, so that the tunnel T shown in FIG. Is to be built.

  Each cross-sectional shape of the illustrated through hole 13 (and the communication hole formed therefrom) and the shaft member 20 is rectangular, but other than this shape, at least a triangular cross section, a square cross section, a pentagonal cross section, etc. An arbitrary polygonal shape having a plurality of corner angles can be selected.

  Since each cross-section of the through-hole 13 and the communication hole and the shaft member 20 fitted to the through-hole is a polygonal shape having a plurality of corners, even if these combinations are one as shown in the figure, the segment The rotation between 10 and 10 is effectively suppressed, and a highly rigid segment ring can be formed. Of course, there may be two or more combinations of polygonal through-holes (communication holes) and shaft members fitted therein.

  FIG. 4 shows another embodiment of the segment connection structure. In this connection structure 30A, two through holes 13A and 13A having a circular cross section are provided on the side of the convex portion 11 of each segment 10A constituting the connection structure 30A, and the convex portions of both segments 10A and 10A are provided. The corresponding through holes 13A and 13A of the portions 11 and 11 communicate with each other to form two communication holes, and shaft members 20A and 20A having a circular cross section are inserted into the respective communication holes.

  When each cross section of the through hole 13A (or the communication hole) and the shaft member fitted to the through hole 13A is circular, the rotation of the segment can be suppressed by providing at least two of these combinations. Therefore, in addition to the illustrated example, the segments may be connected by a combination of three or more communication holes and shaft members.

  FIG. 5 shows a connection structure in a ring joint formed when an endless ring segment unit having a connection structure 30A is connected to the segment joint in the axial direction of the tunnel. However, the segment shown here is slightly different from the segment 10A shown in FIG. 4, and a plurality of concave grooves 14 are formed on an end surface that serves as a ring joint of the segment 10A, and the shaft constituting the connection structure 30A. Both ends of the member 20A protrude from both end surfaces.

  The ring joint is formed in a posture in which the segment unit connection structure 30A adjacent to one segment unit connection structure 30A is offset. Here, the groove 14 is formed at the end face position of the other segment unit corresponding to the shaft member 20A formed in one segment unit, and the corresponding shaft member 20A is fitted in each groove 14 respectively. Thus, the connection structure 40 at the ring joint is formed.

  According to the embodiment shown in FIG. 5, the connection structure at the segment joint and the connection structure at the ring joint can be formed simultaneously and with a simple structure. In addition, the rotation of the segments at both joints can be effectively suppressed.

  The connection structure in the segment joint of the present invention described above is an extremely simple structure in which the segment end is formed in one step shape and the shaft member is inserted into the formed communication hole. Similarly, the connection structure in the ring joint is a simple structure in which the shaft member constituting the connection structure of the segment joint is fitted in the concave groove formed in the segment end face. Furthermore, a shield tunnel can be constructed by preparing a large number of segments of one shape only by producing a segment forming form in a corresponding shape. Therefore, it is possible to construct a highly rigid shield tunnel in which the rotation at the segment joint and the ring joint is suppressed without increasing the construction cost.

[Summary and result of loading test of segment joints]
The inventors manufactured the experimental heating furnace 100 shown in the side view of FIG. 6 and the plan view of FIG. 7 and installed the test pieces M1 and M2 of two segments connected to the experimental heating furnace 100. , M2 was heated from one side to measure the horizontal displacement of each part of the specimens M1 and M2.

  Here, a jack 102 having a performance of 1000 kN was attached to the jack reaction force base 101, and the segment joint surfaces Ma of the two test bodies M1 and M2 were pressed from the back surface by this jack. The test bodies M1 and M2 are erected on the side by connecting fittings 107, and the upper side of the test body M1 protruding from the furnace lid 104 is pressed downward by the loading device 103 having 20MN performance from above. It was supposed to be. The pressing by the loading device 103 reproduces the axial compression force generated by the earth pressure acting on the segment, and the pressing from the back surface by the jack 102 reproduces the earth pressure acting on the segment. Here, the test bodies M1 and M2 are manufactured with a length of 2 m and a thickness of 40 cm.

  A heating device 106 is provided on the front side of the test bodies M1 and M2, thereby reproducing a fire in the tunnel. A fireproof heat insulating material M6 is provided below the front surface of the test body M2. A plurality of thermocouples 105 were provided on the front side of the segment joint portion, and experiments were performed while confirming that the segment joint portion had a predetermined temperature atmosphere.

The experimental procedure is as follows. First, a load is held while increasing the load up to 4800 kN by the loading device 103 at a position deviated by 80 mm from the center line of the test samples M1 and M2 toward the heating device 106, and then the test sample is checked by the jack 102. It loaded to 100 kN in the horizontal direction from the back surface of M1 and M2. In this state, the cross-sectional average compressive force acting on the specimens M1 and M2 is 10 N / mm ² , the bending moment is about −290 kN · m, and the compressive stress on the heating device side of the specimens M1 and M2 is about 19 N / mm. ² is estimated.

  The specimens M1 and M2 were heated according to the RABT curve (60 minutes) in FIG. The heating range of the test bodies M1 and M2 is a total range of 2 m, with a width of 1.2 m and a height of 1 mm above and below the joint surface Ma. During heating, a compressive force of 4800 kN was applied by the loading device 103, and the horizontal load from the jack 102 was appropriately adjusted so that the displacement of the joint portion did not increase or decrease.

  Further, when the test bodies M1 and M2 are not broken up to 170 minutes after heating, the horizontal load of the jack 102 is unloaded, and then the load of the loading device 103 is increased until the fireproof segments M1 and M2 are broken. We decided to grasp the residual strength in the procedure.

  FIG. 9 is a graph showing the displacement measurement result in the step of gradually increasing the vertical load by the loading device 103 among the loading heating experiment results. Step No. of this experiment 1 to Step No. In 37, the load was gradually increased to 4800 kN. In FIG. The horizontal displacement of each part of the test body at the time of gradually increasing loading up to 10 is shown. Here, a line having a height of 2000 mm indicating the maximum displacement is a line of the joint surface Ma of the test bodies M1 and M2.

  FIG. 10 is a graph showing a displacement measurement result in the step of gradually increasing the horizontal load by the jack 102 in a state in which the load by the loading device 103 is kept at a constant value of 4800 kN among the results of the loading heating experiment. Step No. of this experiment In the steps after 38, the horizontal load is gradually increased up to 100 kN by the jack 102 with the load from the loading device 103 kept at 4800 kN. 49-step no. In 59, the familiarity of the specimen was confirmed. In FIG. The horizontal displacement in each part of the test body from 41 to 50 is shown.

  FIG. 11 shows the result of measuring the relationship between the temperature and time in the experimental heating furnace (each part of the six thermocouples 105) together with the RABT curve.

  FIG. 12 shows the bending moment generated in the specimen in time series, and FIG. 13 shows the temperature of each part of the specimen in time series.

  Furthermore, FIG. 14 shows the horizontal displacement of each part of the test specimen from time: 170 minutes to 210 minutes.

  Regarding the test specimen after heating, the test specimens M1 and M2 were destroyed by reducing the load by the jack 102 in a state where the load of the loading device 103 was 4800 kN. When the specimens M1 and M2 after destruction were observed, the concrete on the heating side of the joint portion of the specimen was crushed. Cracks parallel to the heating surface were observed on the side surface of the test body taken out from the experimental heating furnace 100. Furthermore, in this joint part, the crack had arisen so that the hole for installing PC steel rod might be connected. Furthermore, as shown in FIG. 13, the temperature of the rebar and the main rebar rises again around 190 minutes. This is because the concrete on the heating side is crushed, causing cracks in the concrete. This is due to the fact that the film became thinner or partly exposed in the furnace. In addition, the bending moment of about 190 minutes considered that this test body was destroyed is specified as -348 kN * m from FIG.

  From the above experimental results, if this is heated while a negative bending moment is acting on the specimen, the heated surface will be crushed by a larger compressive stress than the back surface (non-heated surface). It was proved that the specimen could break when it could not hold the axial force.

  Therefore, when there is a segment joint in the area where a negative bending moment is acting during normal earth pressure action, suppressing the rotation of this joint part prevents the segment from collapsing at this segment joint. This leads to an improvement in the fire resistance of the shield tunnel. By constructing the tunnel having the segment connection structure of the present invention described above, the rotation of the segment at the segment joint can be suppressed, and the fire resistance performance of the shield tunnel can be improved.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

It is the perspective view which showed the tunnel provided with the connection structure of the segment of this invention. It is a disassembled perspective view of two segments and a shaft member which comprise the connection structure of the segment of this invention. It is a perspective view of one Embodiment of the connection structure of the segment comprised by the two segments and shaft member shown in FIG. It is a perspective view of other embodiment of the connection structure of a segment. It is a top view of other embodiment of the connection structure of a segment. It is a side view of the load heating experiment apparatus of a segment joint part. It is a VII-VII arrow line view of FIG. 6, Comprising: It is a top view of the load heating experiment apparatus of a segment joint part. It is a RABT curve in a loading heating experiment. It is the graph which showed the displacement measurement result in the gradual increase loading step of the vertical load by a loading apparatus among loading heating experiment results. It is the graph which showed the displacement measurement result in the gradual increase loading step of the horizontal load by a jack in the state where the load by a loading device was made into a fixed value among loading heating experiment results. It is the graph which showed the relationship between the temperature in an experimental heating furnace, and time. It is the graph which showed the relationship between the bending moment which generate | occur | produces in a test body, and time. It is the graph which showed the relationship between test body temperature and time. It is the graph which showed the horizontal displacement of each site | part of a test body in 170 to 210 minutes. It is the figure which showed the earth pressure which acts on the tunnel of a circular section, and the bending moment distribution which generate | occur | produces. It is the figure which expanded the XVI part of FIG. 11 in the case of a fire in a tunnel.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Segment, 11 ... Convex part, 12 ... Concave part, 13, 13A ... Through-hole, 14 ... Concave groove, 20, 20A ... Shaft member, 30, 30A, 40 ... Connection structure, T ... Tunnel, R ... Circumferential direction, A ... Axial direction

Claims (2)

In the connection structure of the segments that constitute the tunnel by being connected in the circumferential direction and the axial direction in the borehole,
In the segment, both end portions forming a segment joint are formed in a stepped shape including a convex portion and a concave portion in the circumferential direction, and the convex portion is formed with one or a plurality of axial through holes having a polygonal cross section. In addition, in a posture in which the convex portion of one segment is fitted into the concave portion of the other segment, a communication hole in which both the through holes communicate in the axial direction is formed, and both ends projecting from the shaft member are fitted. Concave grooves are formed at positions corresponding to the respective shaft members,
It said segments, in the convex portion of one segment is fitted in the recess of the other segment position, the shaft member of the cross-sectional dimension in the communication hole having the same shape is inserted before Killen hole,
Connection structure in the plurality the segments of being connected circumferentially endless segment joint segment unit Ru is formed is formed,
Aitonaru the segment unit, the together when the segment joint are connected in a posture mutually offset, the both ends of both end faces of the joint of any segment units before Kishotonariru segment unit wherein a plurality of shaft members projecting in the axial direction of the segments, are fitted to each other in said corresponding groove formed on the end face of the other segment units,
A connection structure of segments, wherein a connection structure is formed at a ring joint in which segment rings are connected in a tunnel axis direction to construct a tunnel .   A tunnel comprising the segment connection structure according to claim 1.

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