JP4828286B2 - Segment connection structure and layout structure - Google Patents

Description

  The present invention relates to a connecting structure and an arrangement structure of segments used when connecting adjacent segments in the circumferential direction to form a tunnel, and in particular, the outer periphery of a tunnel branching / merging portion where two tunnels branch or merge. It is related with the connection structure and arrangement | positioning structure of a suitable segment in doing.

  Conventionally, the so-called shield tunnel constructed based on the shield method is mainly a tunnel with a circular cross section that is structurally stable. However, as the development of urban underground road networks in recent years has progressed, the number of cases where a tunnel branching / merging section where two tunnels branch or merge is required increases. In particular, this tunnel branching junction is frequently used in the case where one lamp tunnel is connected to one main tunnel.

  Conventionally, the main part of the tunnel junction is the open-cut method of construction where the ground is dug down from the ground surface. This open-cut method has the advantage that the soil and water pressure acting on the tunnel during construction can be made relatively small in order to remove the ground between the tunnels.

  However, in this excavation method, the construction location of the tunnel branching junction is limited to a place where excavation work from the ground surface can be performed. That is, in the case of performing construction based on the open-cut method, there has been a problem that a site for constructing the tunnel branch junction must be secured. In addition, when such a tunnel branch and junction must be constructed in a deep underground, the excavation labor for such excavation becomes excessive, and the construction cost including groundwater countermeasures is expensive.

  For this reason, from the viewpoint of land saving and suitable for deep tunnel construction, the construction method of the tunnel junction / merging section in recent years is shifting from the above-mentioned open-cut method to the so-called non-cut-open method.

  As shown in FIG. 18, this non-opening method is a tunnel branching junction for connecting the main tunnel 202 and the ramp tunnel 203 using the lateral hole 201 opened in the ground without excavating the ground from the ground surface. Build up. At this time, since an overload from the ground 204 above the tunnels 202 and 203 acts, earth and water pressure acting on each of the tunnels 202 and 203 is greatly generated at the time of construction of the tunnel branching junction. In addition, although the method of constructing a tunnel branching junction based on this non-cutting method is disclosed in, for example, Non-Patent Document 1, in any method, the segments can be surely connected to each other in a limited space. There was a need for a high strength connecting structure that can be connected.

  FIG. 19A shows a completed view of the tunnel branching / merging portion 206 for branching or joining the main tunnel 202 and the ramp tunnel 203 constructed based on this non-cutting method. When this tunnel branching / merging portion 206 is applied to a deep tunnel in which the earth covering in the ground 204 exceeds 50 m, a large groundwater pressure of 0.5 MPa or more acts in addition to the earth pressure. FIG. 19B shows the distribution of the bending moment acting on the tunnel branching junction 206. The tunnel branching / merging portion 206 is configured as a horizontally long tunnel cross section including the main tunnel 202 and the lamp tunnel 203, and a large positive bend occurs in the horizontally long portion. This positive bending acts in such a way that a tensile force is applied to the inner surface of the tunnel. For this reason, in the tunnel branching junction 206, it is necessary to establish a high-strength, high-rigidity inter-segment connection structure capable of resisting such a large positive bending, and further, between the segments having high water-stopping performance. There was also a need for a connected structure.

  Conventionally, in order to meet the needs required for the connection structure of the tunnel branching / merging portion 206 as described above, the strength and rigidity equivalent to those of the segment main body are obtained by welding and fixing the circumferential contact surfaces of the circumferentially adjacent segments. A construction method for ensuring the above has been proposed. In this construction method, it is also possible to configure a water stop structure by continuing the weld line between the segments. However, such a welding operation has a problem of requiring a great deal of labor and time. Specifically, the joint connection work per location may take several hours or more, and if there are many joint connection locations, the construction period may be significantly extended. In particular, when a high-strength steel or a thick plate having a thickness of 50 to 100 mm is adopted, there has been a problem that on-site management such as the preheating temperature of the weld connection part and the temperature between welding passes becomes complicated.

  Conventionally, a method has also been proposed in which a joint structure is formed with high strength by bolting joint plates formed on circumferential contact surfaces of adjacent segments. In this method, it is possible to secure the water stop of the joint by disposing a water stop material between the joint plates. It is also possible to perform the bolt fastening operation from the inner surface of the tunnel. However, when constructing a connection structure where a large bending moment is applied, the strength and rigidity of such joints depend on the specifications of the bolts and joint plates. There is a problem that large proof stress and rigidity cannot be secured.

  In addition, a method has been proposed in which the above-described bolt diameter is increased, the bolts are arranged in multiple stages, and the thickness of the joint plate is increased to increase the strength and rigidity. However, in order to increase the diameter of such a bolt, for example, the bolt diameter of about M20 mm must be increased to about M56 mm. There is also an adverse effect that the burden on the operator increases in the tightening operation for wearing. There is also a method of using a bolt tightening device to tighten the bolt, but the bolt tightening device becomes larger as the diameter of the bolt increases, so there is a problem that a sufficient working space cannot be secured. there were. In addition, when the bolts are arranged in multiple stages, such as two stages, three stages, and four stages, the distance between adjacent bolts is extremely narrow, for example, about several tens of millimeters, and it is difficult to perform fastening work on site. There was a problem that it was impossible to achieve high yield strength.

  Furthermore, in the past, in addition to jointing the joint plates formed on the circumferential contact surfaces of the segments with bolts, the connecting plate is friction-joined with bolts, thereby increasing the link structure's strength and rigidity. A method for achieving this has also been proposed (see, for example, Patent Document 1).

  In general, as a technique for increasing the strength and rigidity of a joint part, a bolt joining method using an attachment plate frequently used as an on-site joint for H-shaped steel of a building structure has been proposed. As a result, there is a problem that the water stop performance is significantly deteriorated. In addition, there is a problem that it is difficult to fasten the joint bolt on the natural ground side from the inner surface of the tunnel.

  Then, the connection structure of the steel segment as a technique disclosed in Patent Document 1 has been devised to solve such a problem. That is, in this connection structure, for example, as shown in FIG. 20, an end plate 112 as a joining surface of segments adjacent in the circumferential direction is installed only above the neutral shaft. And this end plate 112 is joined with the short volt | bolt 113 between the adjacent other segments. A main girder 111 perpendicular to the axial direction of the tunnel is disposed in the open portion below the neutral shaft, and one end of the attachment plate 115 is fixed to the main girder 111 by a bolt. Also, the other end of the splicing plate 115 is bolted to the web of the main beam of the adjacent segment. Thereby, a joint part exhibits sufficient rigidity more than equivalent to the main girder 111 with respect to bending.

  That is, the connecting structure described in Patent Document 1 can achieve high strength and rigidity of the joint between segments, and further realize a water stop structure by disposing a water stop material on the end plate 112. Is possible.

However, since the connection structure described in Patent Document 1 needs to transmit all stress between the segment joints, the specifications of the attachment plate and the connecting bolt become large, and as a result, the segment production cost, material cost, etc. There was a problem that the increase in cost could not be avoided, and further the on-site connection time was increased. Further, in the connection structure described in Patent Document 1, since the main girder 111 is provided with a proof strength, a place where a large bending moment is applied, such as a branching junction such as a large-section tunnel or a deep tunnel. There is a problem that application becomes difficult.
JP-A-11-22393 "Construction Machinery" Nihon Kogyo Publishing, November 2005, P1-P56

  Therefore, the present invention has been devised in view of the above-described problems, and the object of the present invention is to connect the segments constituting the outer periphery of the tunnel branching / merging portion where two tunnels branch or join, and In the arrangement structure, it can resist a large bending moment that acts as a pulling force toward the inner surface of the tunnel, can reliably connect even in a narrow field space, and can streamline the structural specifications of the joint. An object of the present invention is to provide a connecting structure and an arrangement structure of segments having high strength and high rigidity.

The segment connection structure according to claim 1 is a tunnel segment connection structure used when adjacent segments are connected to each other, and the joint plates formed on the natural ground side on the circumferential contact surface of the segment. Are joined by bolts and perpendicular to the axial direction of the tunnel, and a main girder having a web and a flange formed on at least the inner surface of the web is disposed at both ends in the axial direction of the segment and at least in the middle. The lower flanges of the main girders are configured with a gap between them at a position spaced from the circumferential contact surface, and are configured as a single steel plate at a position close to the circumferential contact surface. Between the main girders in the segment adjacent in the direction, a splicing plate is installed, and the splicing plate and the main girder are bolted to each other. They are joined, the spliced plate, it becomes from a single steel sheet, characterized by comprising been laid on the bottom of the formed lower flange as steel one above.

  The segment connection structure according to claim 2 is the segment connection structure according to claim 1, wherein the webs of the main girders arranged at both axial ends of the segments adjacent in the axial direction are at least joint portions. It is characterized by being bolted over a plurality of stages in the vicinity.

  The segment connection structure according to claim 3 is the segment connection structure according to claim 1 or 2, wherein the attachment plate includes a bottom surface of a lower flange in the main girder, a top surface of a lower flange in the main girder, It is constructed in any one or more of the webs in the main girder.

  The segment connection structure according to claim 4 is the segment connection structure according to any one of claims 1 to 3, wherein the joint plate and the main girder are continuously connected from the ground side to the inner surface side. It is characterized in that a water stop material is provided to prevent leakage of groundwater to the ground.

  The segment connection structure according to claim 5 is the segment connection structure according to any one of claims 1 to 4, wherein the attachment plate is constructed on the bottom surface of the lower flange in the main girder. In addition, it is widened in the axial direction so as to straddle the adjacent segment rings in the axial direction.

The segment connection structure according to claim 6 is the segment connection structure according to claim 1, wherein the lower flange is formed with a gap between the lower flange and the lower flange as the single steel plate. A triangular reinforcing piece that can be fitted to the formed corner is fixed.

The segment connection structure according to claim 7 is the segment connection structure according to any one of claims 1 to 6 , wherein the joint plates formed on the circumferential contact surfaces of the segments are joined to each other. And / or the bolts for joining the webs of the main girders are joined via an elastic washer.

The segment connection structure according to claim 8 is the segment connection structure according to any one of claims 1 to 7 , wherein the flanges of the main girders disposed at both axial ends of the segment are webs. It is the structure which does not protrude from the axial direction outer side.

The segment connection structure according to claim 9 is the segment connection structure according to any one of claims 1 to 8 , wherein the first tunnel and the second tunnel branch or merge in the segment. The outer circumference of the tunnel branching junction is configured.

The segment connection structure according to claim 10 is the segment connection structure according to claim 9 , wherein the remaining segment constituting the remaining portion of the first tunnel and the second tunnel and the segment are joined to each other. The planes are arranged so as to be straight in the axial direction, and the segments constituting the outer periphery of the branching / merging portion are arranged so as to be staggered with respect to each other.

In the segment joint structure to which the present invention is applied, the compressive force is transmitted between the joint plates to be contacted between the adjacent segments in the circumferential direction, and the tensile force is transmitted by the attachment plate installed on the main girder. Is possible. The shearing force applied to the segment can be transmitted through a bolt (not shown) inserted into the bolt hole of the joint plate and screwed. As a result, the stress transmission performance in the circumferential direction can be improved, and the bending moment applied to the segment can be countered.

  In addition, since the connecting structure of the segments to which the present invention is applied can be configured by bolt joints, the joint connection time per place can be handled within about one hour, and the number of management items in the field is reduced. This makes it possible to shorten the construction period. In addition, since it is not necessary to complicate the structure of the connection structure as in the prior art, it is possible to reduce the cost.

  Hereinafter, as a best mode for carrying out the present invention, a connection structure of segments constituting the outer periphery of a tunnel branching / merging portion where two tunnels branch or join will be described in detail with reference to the drawings.

  In the tunnel branching / merging unit 1 to which the segment connection structure to which the present invention is applied is applied, for example, as shown in FIG. 1, the main tunnel 11 and the ramp tunnel 12 merge and connect to one tunnel 13. In other words, it is a portion that branches from one tunnel 13 to the main tunnel 11 and the ramp tunnel 12. Incidentally, FIG. 1A shows a configuration from one tunnel 13 to two branches from the main tunnel 11 and the ramp tunnel 12, and FIG. 1B shows the configuration shown in FIG. 1A is a cross-sectional view taken along line BB, FIG. 1D is a cross-sectional view taken along line CC, and FIG. 1E is a cross-sectional view taken along line DD.

  Here, the case where the main tunnel 11 and the ramp tunnel 12 merge and connect to one tunnel 13 will be described as an example. The main tunnel 11 and the ramp tunnel 12 are embedded in the ground in a form in which a circular cylindrical segment ring is continued in the tunnel axis direction, as shown in the DD cross-sectional view. Here, a target section k1 shown in FIG. 1A is a section where the main tunnel 11 and the ramp tunnel 12 merge. When entering the target section k1 and joining the tunnels 11 and 12, for example, as shown in the CC cross-sectional view, the segment remaining portion 11a constituting the outer periphery of the main tunnel 11 and the ramp tunnel 12 A segment is newly provided between the remaining portion 12a of the segment that has formed the outer periphery, and a partition wall 15 is further provided. A region where the newly established segments are continuous is referred to as a new portion 14.

  In the target section k1, the central axes of the main tunnel 11 and the ramp tunnel 12 gradually approach each other, and accordingly, the length of the new section 14 is gradually shortened as shown in the BB sectional view. The partition wall 15 is also removed. And finally it connects with the one circular cylindrical tunnel 13 as shown by AA sectional drawing, and the target area k1 is complete | finished.

  The connecting structure of segments to which the present invention is applied is used when connecting in the circumferential direction of adjacent segments newly installed in the newly installed portion 14.

  FIG. 2 is a perspective view of a segment connecting structure 2 to which the present invention is applied. The connection structure 2 is adjacent to the joint plate 23 formed above the neutral shaft 22 on the circumferential contact surface 21 of the segment 3 and main girders 24a to 24c orthogonal to the axial direction of the tunnel in the circumferential direction. There are attachment plates 25a to 25c installed between the main girders 24 in the other segments.

  The segment 3 is a steel shell segment manufactured by assembling or casting a steel plate, or a synthetic segment in which the steel shell is filled with concrete. The example of FIG. 2 shows a steel shell segment, and the natural ground surface is covered with a skin plate 26. When the segment 3 is composed of a composite segment, a reinforcing structure in which a reinforcing bar and a deformed steel bar (not shown) are arranged inside the concrete may be employed.

  In this segment 3, three main beams 24a to 24c are further arranged. The main girder 24a and the main girder 24c are disposed at both ends of the segment 3 in the axial direction. The main beam 24b is disposed at least between the main beam 24a and the main beam 24c. The main girders 24a to 24c have webs 31a to 31c, upper flanges 32a to 32c and lower flanges 33a to 33c formed above and below the webs 31a to 31c, respectively. The plate thickness and width of the upper and lower flanges are set by design calculation based on the optimal combination mainly depending on the axial force and bending moment. In some cases, it may be rational to eliminate the flange on the natural ground side and increase the thickness of the skin plate to reduce the manufacturing cost.

  The upper flanges 32 a to 32 c are fixed above the neutral shaft 22, and the lower flanges 33 a to 33 c are fixed below the neutral shaft 22. In addition, the lower flanges 33a to 33c are arranged with a gap therebetween. Incidentally, the upper flanges 32a and 32c and the lower flanges 33a and 33c do not protrude from the outside of the webs 31a and 31c in the axial direction so that the main girders 24a and the main girders 24c provided at both ends in the axial direction have a U-shape. It is configured. On the other hand, the main girder 24b formed substantially in the center in the axial direction is fixed in such a shape that the upper flange 32b and the lower flange 33b protrude to both sides via the web 31b. Each lower flange 33 is formed with a bolt hole 41.

  The web 31 has a height of about 500 to 2000 mm, but in practice, the necessary dimensions are determined according to the tunnel depth, tunnel diameter, and the like. Bolt holes 43 are formed in a plurality of stages in the web 31a and the web 31c formed at both ends in the axial direction at least near the joint. The bolt hole 43 is used to join the webs 31a and 31c of the segment 3 adjacent to each other in the axial direction. The number, diameter, and arrangement of the bolt holes 43 are determined according to the axial transmission force required from the design. If the main girder 24 is a segment having a height of about 500 mm, the bolt holes 43 through which the bolts for connecting the rings of the segment 3 are inserted should be about 3 steps × 3 rows. It can be said that it is appropriate from the construction side.

  The relative displacement deformation between the segment rings is the largest in the vicinity of the joint, and becomes smaller as the distance from the joint is increased. For this reason, as installation positions of the bolt holes 43 through which the bolts for connecting the rings of the segments 3 are inserted, it is desirable to arrange a large number in the vicinity of the joint portion. However, the installation space for arranging a large number of bolt holes 43 in the vicinity of the joint is limited, and the installation space for a large fastening machine required for fastening a large-diameter bolt is also limited. For this reason, it is necessary to determine the arrangement of the bolt holes 43 while keeping these in mind. The vicinity of the joint means a range up to about twice the segment height. The distance between the bolt holes 43 is preferably about 100 mm to 150 mm at the minimum from the viewpoint of bolt fastening workability. Further, it is desirable that the intervals between the bolt holes 43 be substantially equal in both the step direction and the column direction.

  The distance between the flanges 32a and 33a in the main girder 24a and the flanges 32b and 33b in the main girder 24b, and the distance between the flanges 32b and 33b in the main girder 24b and the flanges 32c and 33c in the main girder 24c are from the viewpoint of workability. Therefore, it is necessary to secure at least 200 to 300 mm in each case. After securing the dimensions, the number of installation stages of the bolt holes 43 is determined, and then the number of bolt rows is set so as to satisfy the necessary transmission force. Will be determined. The number of bolts installed is at least two. At this time, the outer diameter of the bolt is preferably a large diameter (for example, M48) from the viewpoint of structural performance. However, if the diameter is large, the defect of the bolt hole 43 increases and the cross-sectional defect of the segment 3 also increases. Therefore, the maximum bolt diameter that satisfies the required structural performance of the segment 3 is selected. The bolt holes 43 may be formed at regular intervals even at positions spaced from the vicinity of the joint.

  Further, the thickness of the web 31 may be configured such that the thickness of the central web 31b is twice the thickness of the webs 31a and 31c at both ends in the axial direction. The reason is that the outer main girders 24a and 24c are joined to the main girders 24c and 24a of the segment 3 adjacent in the axial direction so as to match the cross-sectional characteristics of the main girders 24b.

  The joint plate 23 is provided between the web 31a and the web 31b and between the web 31b and the web 31c. The joint plate 23 is disposed so that the segments 3 adjacent to each other in the circumferential direction are in contact with each other. The height of the joint plate 23 is preferably within a cross-sectional range in which a compressive force acts, and thus at least the neutral shaft 22. It is provided above. Further, the lower end of the joint plate 23 is extended to a height that is separated from the lower flange 33 by about 200 mm so that the bolt joining operation of the lower flange 33 and the attachment plate 25 described later can be easily performed. Is desirable.

  The joint plate 23 is provided with bolt holes 42 for screwing short bolts in two stages. The bolt holes 42 are used for abutting the joint plates 23 of the adjacent segments 3 and inserting a short bolt (not shown). The arrangement of the bolt holes 42 is determined by the necessary proof strength of the bolts and the interval required for tightening the water stop material 44. In order to evenly resist the expansion reaction force of the water stop material 44, the distance between the bolts is determined. It is desirable to arrange so that the maximum is about 500 mm. In addition, the distance between the bolt holes 42 is at least about 100 mm so as not to hinder the bolt fastening operation.

  The attachment plate 25a is installed on the bottom surface of the lower flange 33a, the attachment plate 25b is installed on the bottom surface of the lower flange 33b, and the attachment plate 25c is installed on the bottom surface of the lower flange 33c. Each attachment plate 25 is formed with a bolt hole 46, and the bolt hole 46 and the bolt hole 43 of the lower flange 33 are combined to be bolted together. That is, the respective attachment plates 25 are in a state in which the lower flanges 33 in the segments 3 adjacent to each other in the circumferential direction are joined. The required number of bolts for this joining is determined from the transmission strength of one bolt based on the tensile force to be transmitted. Further, the length of the attachment plate 25 is adjusted so as to satisfy the required number of bolts. The thickness of the contact plate 25 is determined by the design transmission force to be transmitted.

  Moreover, the space | interval of the hole 46 for bolts takes the space | interval of about 100-150 mm at the minimum considering workability. The number of bolts arranged in the axial direction of the segment 3 is preferably about 2 to 10 rows.

  A water stop material 44 may be provided around the segment 3. The water blocking material 44 may be composed of a rubber seal member or the like for preventing leakage of groundwater from the natural mountain side to the inner air surface side. It may react to expand the volume and block water. This water stop material 44 is arrange | positioned so that the segments which adjoin in the circumferential direction and an axial direction may face, and 1 or 2 strip | lines are arrange | positioned as needed. The water blocking material 44 may be formed in a groove portion (not shown) formed in advance. The water blocking material 44 is continuously provided from the joint plate 23 to the outer surface of the main beam 24. When the water stop material 44 is arranged on the outer surface of the main girder 24, the distance between the bolts 43 is arranged at a maximum of about 500 mm in order to evenly resist the expansion reaction force of the water stop material 44. It is desirable to do.

  In the above-described example, the case where the three main girders 24 are provided has been described as an example. However, the present invention is not limited to this case, and the main girders 24 may be composed of four or more main girders 24.

  Next, another configuration example of the segment connecting structure to which the present invention is applied will be described with reference to the drawings. In the following configuration examples, the same components and members as those of the connection structure shown in FIG.

  The connection structure 5 shown in FIG. 3 shows an example in which the attachment plate 51 is joined to the upper surface of the lower flange 33. That is, the bolt hole 41 formed in the attachment plate 51 is aligned with the bolt hole 41 formed on each upper surface of the lower flange 33, and a bolt (not shown) is inserted into these to be screwed. The flange 33 and the attachment plate 51 are joined together. An attachment plate 51a is joined to the lower flange 33a of the main beam 24a. Further, the contact plates 51b and 51c are joined to the lower flange 33b of the main beam 24b on both sides of the web 31b. Further, an attachment plate 51d is joined to the lower flange 33c in the main beam 24c.

  The connection structure 6 shown in FIG. 4 shows an example in which the splicing plate 52 is joined to the web 31 of the main beam 24. That is, by aligning bolt holes 46 formed in the attachment plate 52 with bolt holes (not shown) formed in the webs 31a to 31c, inserting bolts (not shown) into these, and screwing them, The web 31 and the attachment plate 52 are joined. An attachment plate 52a is joined to the web 31a of the main beam 24a. Also, the attachment plates 52b and 52c are joined to both surfaces of the web 31b in the main beam 24b. Further, a splicing plate 51d is joined to the web 31c in the main beam 24c. Note that the bolt holes 43 formed in the webs 31 a and 31 c may be shared for joining with the attachment plate 52.

  The connection structure 7 shown in FIG. 5 shows an example in which the joining plate 25 is joined to the bottom surface of the lower flange, the joining plate 51 is joined to the upper surface of the lower flange 33, and the joining plate 52 is joined to the web 31 of the main girder 24. Yes. That is, in this connection structure 7, the three connecting plates 25, 51, 52 are joined to one main girder 24. The connection structure 7 is not limited to the case where the three attachment plates 25, 51, 52 are joined to one main girder 24, but any two or more attachment plates. 25, 51, 52 should just be joined.

  When the connecting structures 3 and 5 to 7 having the above-described configuration are used as joints of the segments 3 constituting the outer periphery of the tunnel branching junction 1, a large bending moment that acts as a tensile force toward the inner surface of the tunnel It becomes possible to counter such as.

  FIG. 6 shows a cross-sectional structure of the segment 3 to which the connecting structure 7 is applied. A bending moment as indicated by an arrow in the figure is applied to such a segment 3 from the inner sky surface side to the natural ground side. As a result, a compressive force is applied above the neutral shaft 22 and a tensile force is applied below the neutral shaft 22. This compressive force can be transmitted between the joint plates 23 that should contact each other between the segments 3 adjacent in the circumferential direction. Further, this tensile force is transmitted by the contact plates 25, 51, 52 installed on the main girder 24. In addition, a shearing force is applied to the segment 3, and this applied shearing force is transmitted through a bolt (not shown) inserted into the bolt hole 23 of the joint plate 42 and screwed. Will be.

  Regarding the axial direction, it is possible to transmit stress by a bolt (not shown) screwed in the axial direction through a bolt hole 43 formed in the web 31a and the web 31c. This makes it possible to reinforce the axial stress transmission resistance around the joint portion of the segment 3. By arranging multiple bolts (not shown) that are screwed into the bolt holes in the vicinity of the joints, it is possible to improve the stress transmission performance to the rings adjacent in the axial direction.

  Incidentally, in FIG. 6, the connection structure 7 has been described as an example. However, in the other connection structures 3 and 5 to 6, the proof stress and rigidity can be improved in the same manner. However, particularly in this connection structure 7, since a plurality of attachment plates 25, 51, 52 are installed on one main girder 24, it is possible to more significantly improve the resistance to bending moment.

  Particularly, in this connection structure 7, a plurality of attachment plates 25, 51, 52 are installed on one main girder 24, so that it is possible to improve resistance to bending moment. That is, the connecting structures 3 and 5 to 7 according to the present invention can increase both the yield strength and the rigidity.

  The connecting structure 8 shown in FIG. 7 is constructed such that a connecting plate 53 is installed on the bottom surface of the lower flange 33 in the main girder 24 and the connecting plate 53 straddles the rings of the segments 3 adjacent to each other in the axial direction. An example in which the diameter is expanded is shown. The attachment plate 53 is suitably about 9 mm to 70 mm thick. Thus, by joining the attachment plate 53 having a diameter expanded between the rings to the lower flange 33 of the segment 3 adjacent in the axial direction, the shear stress transmission performance in the axial direction can be improved.

  In this connection structure 8, for example, as shown in FIG. 8, a contact plate 51 may be further installed between the lower flanges 33 adjacent in the circumferential direction. Thereby, it becomes possible to further improve the resistance to the bending moment. In order to further enhance the stress transmission performance in the axial direction, for example, the attachment plate 54 may be joined across the ring of the segment 3.

  In the connecting structure 10 shown in FIG. 9, the lower flange 33 d in each main girder 24 is configured as a single steel plate integrated with each other toward the circumferential contact surface in the segment 3. Further, the attachment plate 55 installed in the circumferential direction on the bottom surface of the lower flange 33d is made of a single integrated steel plate. A bolt hole 46 is formed in the attachment plate 55, and a bolt hole 41 compatible with the bolt hole 46 is formed in the lower flange 33d. When the attachment plate 55 is installed on the lower flange 33d, the bolt hole 46 and the bolt hole 41 are aligned, and a bolt (not shown) is inserted and fixed thereto.

  In this connection structure 10, the area of the attachment plate 55 can be increased, and consequently the number of bolts can be increased, so that the transmission resistance can be increased.

  FIG. 10 is a rear view of the connection structure 10 from the inner surface side. At positions separated from the circumferential contact surface 21, the flanges 33 a to 33 c constituting the main girders 24 a to 24 c are arranged with a gap therebetween. On the other hand, in the vicinity of the circumferential contact surface 21, the flanges 33 a to 33 c are constituted by a flange 33 d as a single steel plate integrated with each other. The contact plate 55 is constructed from the bottom surface of the flange 33d. Incidentally, when the bolt is inserted into the bolt hole 46 and screwed, the hand can be extended from the gap formed between the flanges 33a to 33c.

  Corner portions 60 are formed between the lower flanges 33a to 33c in the main girders 24a to 24c and the lower flange 33d configured as a single steel plate. The corner portion 60 is generally 90 °. You may make it fix to each corner part 60 the reinforcement piece 58 of the right triangle shape which can be fitted to this corner part 60. FIG. Thereby, it is possible to smoothly transmit stress between the lower flanges 33a to 33c and the lower flange 33d.

  FIG. 11 (a) shows an enlarged configuration when the coupling plates 23 adjacent to each other in the circumferential direction in the coupling structures 3 and 5 to 9 are joined with a short bolt. A short bolt 62 is inserted into a bolt hole 42 drilled in the joint plate 23, and this is screwed with a nut 63 to fix each other. At this time, an elastic washer 64 may be interposed in the gap between the short bolt 62 and the joint plate 23 and in the gap between the nut 63 and the joint plate 23. The material constituting the elastic washer 64 may use hard rubber.

  In particular, during an earthquake in which repeated stress is applied, for example, as shown in FIG. 11 (b), the connecting structure 7 is subjected to a bending moment as indicated by an arrow in the figure from the natural ground side to the inner sky surface side. There is also a case. As a result, a tensile force is applied above the neutral shaft 22, and a compressive force is applied below the neutral shaft 22. By interposing the elastic washer 64 as described above with respect to the short bolt 62, even when a tensile force is applied, the elastic washer 64 is compressed to absorb the opening displacement of the joint plate 23 due to the earthquake. It is possible to suppress the bolt breakage. By the way, the number of short bolts 62 to be arranged is determined by the seismic external force.

  Next, the construction method of the tunnel branch junction 1 to which the connection structures 3 and 5 to 9 are applied will be described in detail with reference to the drawings. As shown in FIG. 12, first, in the main tunnel 11, the remaining portion 11a and the removal portion 11b are separated. Similarly, in the ramp tunnel 12, the remaining portion 12a and the removal portion 12b are separated. Next, the segments constituting the removal portions 11b and 12b are removed.

  Next, the ground between the main tunnel 11 and the ramp tunnel 12 is excavated in the ground, and the ground 71 and the ceiling 72 of the cavity 70 as shown in FIG. 13 formed by the excavation are frozen. The reason for this freezing is to prevent water from entering the cavity 70.

  Next, as shown in FIG. 14, a new part 14 is newly provided between the remaining part 11a and the remaining part 12a. The newly installed portion 14 constitutes the outer periphery of the tunnel branching / merging portion 1. The connection structure 3 according to the present invention is applied to the connection in the circumferential direction of the segments 3 constituting the newly installed portion 14.

  When installing the new installation part 14, the steel shell of the segment 3 is assembled in advance in the factory, and the bolt hole machining and the seal groove machining for disposing the water stop material 44 are carried out and carried into the site. A bolt and a drilling plate, and an elastic washer are carried into the site, and then a water stop material 44 is disposed in the seal groove.

  In the field, the joint plates 23 of the segments 3 are abutted against each other. Then, a short bolt is inserted into the bolt hole 42 and fastened. Next, bolts are fastened to the contact plates 25, 51, 52.

  The construction method of the newly installed part 14 will be described in more detail. FIGS. 15 and 16 show a cross-sectional view of the tunnel branch junction 1 on the left side, and a top view of the tunnel branch junction 1 on the right side. This top view shows a case in which 1 to 6 rows of segment rings are formed from the left side to the right side in the drawing. From step S11 to step S15, the newly installed portion 14 extends from 1 row to 6 rows. Shows the case of building.

  In step S11, the separation between the remaining portion 11a and the removal portion 11b in the main tunnel 11 and the separation between the remaining portion 12a and the removal portion 12b in the ramp tunnel 12 are not yet completed. It remains as it is. In such a case, the flow of force in the circumferential direction of the tunnel indicated by the arrows in the figure is parallel to each other without straddling the segment ring.

  Next, it transfers to step S12 and the segment which comprises the removal parts 11b_1 and 11b_2 and 12b_1 and 12b_2 which comprise the 1st-2nd column is removed. The cross-sectional view in step S12 shows a state in which the segments constituting the removed portions 11b_1 and 11b_2 and 12b_1 and 12b_2 have been removed, and the ground surface 71 and the ceiling 72 of the cavity portion 70 have been frozen. Incidentally, in this step S12, in the 3rd to 6th rows, the ground pile 77 remains between the removed portions 11b and 12b.

  In this step S12, the stress flowing in the first and second rows flows into the removal portions 12b_3 to 12b_6.

  Next, the process proceeds to step S13, and a new part 14_1 is constructed in the first column. Here, the case where two segments 3 are connected in the circumferential direction is illustrated for the newly installed portion 14_1. Any one of the connecting structures 3 and 5 to 9 described above is applied to the joint portion of the segment 3 (in the following description, the case where the connecting structure 3 is applied will be described as an example). ). Incidentally, the cross-sectional view shown in step S13 shows a cross section of the first-row segment ring in which the new portion 14_1 is constructed.

  Next, the process proceeds to step S14, and the segments constituting the removal units 11b_3 and 12b_3 constituting the third row are removed. In this step S14, in the 4th to 6th rows, the ground mountain 77 still remains between the removed portions 11b and 12b. In step S14, the stress that has propagated in the second row flows into the new portion 14_1 in the first row, and the stress that has propagated in the third row flows into the fourth row.

  Next, the process proceeds to step S15, and the new section 14_2 is disposed in the second row. The segments 3 constituting the new part 14_2 are arranged in a staggered manner with the segments constituting the new part 14_1. The segment 3 constituting the newly installed portion 14_2 is arranged so as to be a so-called potato joint with respect to the remaining portion 12a between the segment 3 constituting the newly installed portion 14_1. Thereby, the segment which comprises the remaining part 12a, and the segment 3 which comprises the said newly installed part 14_1 and 14_2 are arrange | positioned so that a mutual joint surface may become a straight line toward an axial direction.

  In particular, in the joint portion between the remaining portion 12a and the newly installed portion 14_1, it is necessary to make a joint that is excellent in connection work because the adjacent ring segments 3 need to be newly installed, and the bending moment is not large. It is desirable to use a tuber joint. On the other hand, since the bending moment is large in the central portion of the segment constituting the newly-installed portion 14 and there is no contact with the remaining portions 11a and 12a, it is desirable to configure in a staggered arrangement.

  After the construction of the new part 14_2 is completed, the excavation of the ground pile 77 in the fourth row is started. That is, in this construction method, by removing the removal parts 11b and 12b in the next line of the line where the new installation part 14 is actually constructed first, for example, the ring of the segment 3 such as the connection structure 8 is straddled. It is possible to easily perform the joining work to the attachment plate 53. In addition, the connection of the segment 3 which comprises the newly installed part 14, and the segment which comprises the remaining parts 11a and 12a may be made to apply another conventional connection structure, without applying the connection structure 3 mentioned above. .

  In the construction method described above, for example, as shown in FIG. 17A, an attachment plate 53 may be installed in advance between the rings constituting the remaining portions 11a and 12a. Thereby, the circumferential stress in the third row shown in FIG. 17A can be distributed and transmitted in the axial direction via the attachment plate 53.

  Moreover, in the construction method described above, for example, as shown in FIG. 17 (b), the above-described connection structure 8 in which the attachment plate 53 is installed between the rings of the segments 3 constituting the newly installed portion 14 is applied. Show. The stress in the circumferential direction of the third row in FIG. 17A can be distributed and transmitted in the axial direction via the attachment plate 53.

  Taking the branch and merge part 1 of a deep tunnel with a cover of 50m as an example, the specifications of the connection structure 2 are estimated.

  The cross section of the branch merge section 1 is a horizontally long tunnel cross section having a total width of 22 m and a height of 15 m. In the case of constructing the branching / merging portion 1 by the non-opening method, it is assumed that the segment 3 constituting the removal portions 11b and 12b is removed during the construction.

  At the maximum positive bending point acting on the tunnel branching junction 206 shown in FIG. 19, the axial force is 6000 kN, the bending moment is 9000 kNm, and the shearing force is 3000 kN (per depth of 1 m).

  The height of the main girder 24 is 1000 mm, the width of the segment 3 is 1200 mm, the thickness of the flanges 32 and 33 of the main girder 24 is 75 mm, the width of the flanges 32a and 33a and the flanges 32c and 33c is 170 mm, and the flanges 32b and 33b. The width of the web 31 is 340 mm, the thickness of the webs 31 a and 31 c is 30 mm, the thickness of the web 31 b is 60 mm, and the thickness of the skin plate 26 is 8 mm.

  Of the cross-sectional force generated in the tunnel (axial force is 6000 kN, bending moment is 9000 kNm, and shearing force is 3000 kN), it is assumed that 30% of the bending moment and shearing force are transmitted to the adjacent ring using bolts between rings.

  The sectional force transmitted and transmitted in the segment joint is 6000 kN for the axial force, 6300 kNm for the bending moment, and 2100 kN for the shearing force. Since the axial force is a compressive force, it is transmitted by the contact of the joint plate and is not involved in the following bolt design. The bending moment of the joint is transmitted by the contact plates 25a to 25c on the inner surface of the tunnel, and the shearing force is transmitted by the short bolt inserted through the bolt hole 42 on the natural mountain side. The specification corresponding to the reduction of the bending moment and shearing force can be reduced.

  That is, the specifications corresponding to 70% transmission of bending moment and shearing force are as follows.

  The height of the joint plate 23 is 5500 mm, the plate thickness is 21 mm, and the bolt holes 42 are 2 stages × 6 rows in one joint plate 23, and the short bolt to be inserted into the bolt holes 42 is M36. Further, the length of the attachment plates 25a to 25c is 750 mm, the plate thickness is 25 mm × 2 sheets (both sides), the arrangement of the bolt holes 46 is 6 stages × 5 rows, and the bolt diameter is M30.

  Next, the specifications of the bolt between rings will be described. First, consider a case where 30% of the bending moment and shearing force are transmitted to the adjacent ring via the inter-ring bolt to be inserted into the bolt hole 43. The transmission force P to this adjacent ring is calculated. That is, it is calculated as a bending moment generated when this transmission force P acts on the adjacent ring as a concentrated load. As a result, the transmission bending moment to the adjacent ring is 2700 kNm and the shearing force is 900 kN.

  When the span length to which the positive bending moment acting on the tunnel branching junction 206 shown in FIG. 19 is applied is 10 m, from the generated bending moment at the center position of the span, 2700 kNm = 1/4 × 10 m × PkN, P is 1080 kN. The bolt between the rings uses a bolt diameter of M30 mm and a surface friction resistance of 161 kN / piece per SHTB bolt, and the necessary number is 1080 kN / 161 kN = 6.7. Similarly, the necessary number of shearing forces is 900 kN / 161 kN = 5.6, which is 12.3 in total. Therefore, if the bolts are distributed and arranged at four places around the segment joint, four inter-ring bolts may be arranged at one place. When securing a bolt interval of 150 mm, it is possible to cope with a digit height of 1000 m in a four-stage arrangement × one row.

It is a block diagram of the tunnel branch merge part to which the connection structure of the segment to which this invention is applied is applied. It is a perspective view of the connection structure of the segment to which this invention is applied. It is a figure shown about the example which joins a splicing board to the upper surface of a lower flange. It is a figure shown about the example which joins a splicing board to the web of a main girder. It is a figure which shows the example which joins a splicing board to the bottom face of a lower flange, the upper surface of a lower flange, and the web of a main girder. It is sectional drawing of the segment to which the connection structure to which this invention is applied is applied. It is a figure which shows the example expanded to an axial direction so that an attachment board may straddle the segment ring adjacent to an axial direction mutually. FIG. 8 is a view showing an example in which an attachment plate is further installed between upper flanges adjacent in the circumferential direction in addition to the configuration of FIG. 7. It is a figure for demonstrating the other structural example of the connection structure to which this invention is applied. It is the figure which visually recognized the connection structure shown in FIG. 9 from the inner surface side. It is a figure for demonstrating the case where an elastic washer is interposed in the clearance gap between a short volt | bolt and a coupling board. It is a figure for demonstrating the construction method of the tunnel branch merge part to which the connection structure which concerns on this invention is applied. It is a figure which shows the cavity part obtained by excavating the ground between a main line tunnel and a ramp tunnel. It is a figure shown about the case where a new installation part is newly provided between remaining parts. It is a figure for demonstrating in more detail the construction method of the tunnel branch merge part to which the connection structure which concerns on this invention is applied. It is another figure for demonstrating in more detail the construction method of the tunnel branch merge part to which the connection structure which concerns on this invention is applied. It is a figure for demonstrating the flow of the stress in the case of constructing an attachment board between rings. It is a figure for demonstrating the prior art example of a non-cutting method. It is a figure which shows the completion figure of the tunnel branch merge part of the main line tunnel and the ramp tunnel constructed | assembled based on the non-open cutting method. It is a figure which shows the prior art example of the connection structure using a volt | bolt and an attachment board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tunnel branch merge part 2 Connection structure 3 Segment 11 Main line tunnel 12 Lamp tunnel 13 Tunnel 14 New part 15 Partition wall 21 Circumferential contact surface 22 Neutral shaft 23 Joint plate 24 Main girder 25 Connecting plate 26 Skin plate 31 Web 32 On Flange 33 Lower flange 41 to 43, 46 Bolt hole 44 Water stop material

Claims (10)

In the connection structure of the segments for tunnels used when connecting adjacent segments to each other,
The joint plates formed on the natural ground side in the circumferential contact surface of the segment are joined with bolts,
A main girder orthogonal to the axial direction of the tunnel and having a web and a flange formed on at least the inner surface of the web is disposed at both axial ends of the segment and at least in the middle thereof.
The lower flange in each main girder is configured with a gap therebetween at a position spaced from the circumferential contact surface, and is configured as a single steel plate at a position close to the circumferential contact surface,
Between the main girders in the circumferentially adjacent segments, an attachment plate is installed, and the attachment plate and the main girders are bolted together.
The connecting structure for a segment, wherein the splicing plate is made of a single steel plate and is constructed on the bottom surface of a lower flange configured as the single steel plate . The web of each main girder arrange | positioned at the axial direction both ends of the segment adjacent to each other in the axial direction mutually is bolted over the multistage at least in the vicinity of the joint part. Connected structure. The said joining plate is constructed in any one or more of the bottom face of the lower flange in the said main girder, the upper surface of the lower flange in the said main girder, and the web in the said main girder. Segment connection structure. Any one of Claims 1-3 characterized by the above-mentioned joint board and the main girder being provided with the water stop material for preventing the leakage of groundwater from the natural ground side to the inner surface side continuously. A segment connection structure according to claim 1. The said attachment board is constructed in the bottom face of the lower flange in the said main girder, and is expanded in the axial direction so that the segment rings adjacent to each other in the axial direction may be straddled. The connection structure of the segment of any one of these. A triangular reinforcing piece that can be fitted to a corner portion formed between the lower flange formed with a gap between the lower flange and the lower flange as the single steel plate is fixed.
The segment connecting structure according to any one of claims 1 to 5, wherein: Bolts fastening bolt, and / or the web between the respective main girder joining fitting plates are formed in the circumferential direction contact surface of the segment, claims characterized in that it is bonded via an elastic washer The connecting structure of segments according to any one of Items 1 to 6 . Flange main girder disposed at both axial ends of the segment, between the segments of any one of claims 1 to 7, characterized in that it is configured not to protrude from the axially outer web Connection structure. The segment connection structure according to any one of claims 1 to 8 , wherein the segment constitutes an outer periphery of a tunnel branching junction where the first tunnel and the second tunnel branch or merge. . The remaining portion segment constituting the remaining portion of the first tunnel and the second tunnel, and the segment are arranged such that the joint surfaces thereof are in a straight line toward the axial direction, and the outer periphery of the branch and merge portion The segment connecting structure according to claim 9 , wherein the segments constituting the segment are arranged in a staggered manner.

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