JP4587918B2 - How to construct a junction and junction of shield tunnel - Google Patents

Description

  The present invention relates to a method for constructing a branching / merging portion of a shield tunnel in which a branching / merging shield tunnel is joined to a main shield tunnel to form a branching / merging portion of the tunnel.

  For example, as a method of connecting a branch and confluence tunnel such as a ramp tunnel to a main tunnel formed in the ground, a ground shaft is formed by excavating the ground of the branch and confluence portion, and a main tunnel and a branch and confluence tunnel are formed inside the shaft. A method of joining the two is considered. In addition, such an open-cut method has a problem in securing construction space and site on the ground, especially in urban areas, and environmental problems to the surroundings are likely to occur. As a method of joining the main tunnel, for example, the main tunnel and the branch and confluence tunnel are separately constructed with an interval, covering the top and bottom of this interval portion and press-fitting a retaining member, or after improving the ground, A method of excavating the gap portion to connect the two (for example, see Patent Document 1), or forming a large-section tunnel at the branching or merging portion of the main tunnel, and branching (merging) direction from inside the large-section tunnel Various methods have been proposed, such as a method of excavating a shield tunnel having a small cross section as a branching and converging tunnel (see, for example, Patent Document 2).

In addition, in the conventional method of joining these branch and junction tunnels and main line tunnels in the ground, it is necessary to perform large ground improvement and mountain retaining works deep in the ground, which increases the construction cost and the construction period. Also gets longer. On the other hand, for the purpose of reducing construction costs and shortening the construction period, it is possible to cut the joint side surface part of the main tunnel formed in the ground by the shield tunneling machine with the shield tunneling machine for the branch and merge tunnel Proposing a construction method that allows the main tunnel and the branch / merging tunnel to communicate with each other by excavating the shield tunneling machine for the branch / merging tunnel while directly cutting the cuttable portion and reaching the main tunnel. (For example, see Patent Document 3).
Japanese Patent No. 2839440 JP 2001-355385 A JP 2004-21361 A

  According to the method for constructing a branching / merging portion of a shield tunnel described in Patent Document 3, the main side tunnel and the branch / merging tunnel are joined by directly cutting the joining side surface portion of the main tunnel using a shield tunneling machine for the branching / merging tunnel. However, it is thought that it will be possible to effectively reduce the construction cost and shorten the construction period, but in actual construction, the main line tunnel will cause cross-sectional defects by cutting the joint side part. Until the body lining is applied, the structure of the branching / merging portion tends to be unstable with respect to earth pressure and water pressure from the surrounding ground. Therefore, when adopting a construction method in which the main tunnel and the junction tunnel are joined by directly cutting the junction side part of the main tunnel with the shield tunneling machine for the branch junction tunnel, the earth pressure and water pressure from the surrounding ground are stabilized. Therefore, there is a demand for the development of a technology that can efficiently perform the construction of the branch / merge part while supporting it.

  The present invention relates to a construction method for forming a branch / merging portion by directly cutting a joint side surface portion of a main tunnel with a shield tunneling machine for the branch / merging tunnel to join the main tunnel and the branch / merging tunnel. Shield tunnel bifurcation that enables efficient construction of branch junctions while stably supporting the earth pressure and water pressure from the surrounding ground until the body lining is applied after the side surface is cut The purpose is to provide a method for constructing a junction.

  The present invention is a method for constructing a branching / merging part of a shield tunnel that joins a branching / merging shield tunnel to a mains shield tunnel to form a branching / merging part of the tunnel, wherein the junction side part of the mains shield tunnel in the branch / merging part A step of forming the tunnel outer body using a cutting segment that can be cut by a branching / merging shield machine, and a load from the vertical direction on the center side of the cutting segment inside the main shield tunnel at the branching / merging portion. And a step of filling and solidifying a poorly mixed solidified material that can be cut by the branching and merging shield machine on the cutting segment side of the main line temporary intermediate pillar to support the standing temporary intermediate pillar, The branch merging shield machine is advanced while cutting the poor blend solidifying material, and the branch A step of sliding the junction side portion of the branch and merge shield tunnel to the junction side surface portion of the main shield tunnel in the flow portion, and a tunnel outer body of the junction side portion of the branch and merge shield tunnel, A lateral temporary support beam is installed between the inner wall surface on the opposite side to the joining side surface portion and the inner wall surface on the opposite side to the joining side portion of the branch and merge shield tunnel, and the junction side of the branch and merge shield tunnel A branch and merge line temporary intermediate pillar that supports a load from the up and down direction in the center side than the section, and a sliding portion between the junction side surface portion of the main shield tunnel and the junction side portion of the branch junction shield tunnel A step of improving the ground around the ground, an uncut cutting segment of the joint side surface portion of the main shield tunnel, and the branch and merge seal A step of removing the tunnel outer body of the junction side portion of the tunnel, a contact surface with the end surface of the tunnel outer body of the main shield tunnel after removing the cutting segment of the side surface portion of the tunnel, and the tunnel outer portion of the joint side portion A connection piece having a contact surface with the end face of the tunnel outer body of the branch and merge shield tunnel after removing the body, and a contact surface with the lateral main support beam is exposed by removing the cutting segment. The upper and lower ground surfaces of the joint side surface portions are respectively disposed and arranged so as to be replaced with lateral temporary support beams, so that the contact surfaces of the upper and lower connection pieces and the joint side surface portions of the main shield tunnel are A shield tunnel including a step of laying the transverse main support beams between the opposite inner wall surface and a step of removing the main line temporary intermediate pillar and the branch merge line temporary intermediate pillar. The above-mentioned purpose is achieved by providing a construction method for the junction part of the junction.

  Further, according to the method for constructing a branching / merging portion of the shield tunnel according to the present invention, the cutting segment is assembled in a state of being tensioned in a circumferential direction by a PC steel wire extending and arranged in a circumferential direction. While sequentially removing from the PC steel wire arranged on the rear side in the digging direction of the merging shield machine, the branch merging shield machine is dug to cut the cutting segment and the poorly mixed solidified material. preferable.

  Further, according to the method for constructing a branching / merging portion of the shield tunnel according to the present invention, the branching / merging shield machine includes a mechanism for forming a shield tunnel having a substantially long circular cross section so that the length of the major axis can be adjusted. It is preferable that it is.

  According to the method for constructing a branching / merging portion of a shield tunnel according to the present invention, a branching / merging portion is formed by directly cutting a joining side surface portion of a main tunnel by a shield excavator for the branch / merging tunnel and joining the main tunnel and the branching / merging tunnel. In the construction method to form the merging section, it is efficient to stably support the earth pressure and water pressure from the surrounding ground until the main body lining is applied after cutting the joint side part of the main tunnel. Can be performed.

  As shown in FIG. 1, for example, in a junction part of a highway, a method for constructing a branch / merge part of a shield tunnel according to a preferred embodiment of the present invention is a branch / merge part 10 of a main line shield tunnel 11 and a branch / merge shield tunnel 12. In order to form the ground in the ground, it is employed when the branch / merging tunnel 11 by the shield method is directly joined to the main tunnel 10 by the shield method. According to the present embodiment, the standard cross section of the main shield tunnel 11 is a circular cross section having a size capable of providing a three-lane road with a lane width of 3.25 mm, for example (see FIG. 2). The standard cross section of the shield tunnel 12 is, for example, a substantially oval cross section having a size capable of providing a two-lane road with a lane width of 3.5 mm (see FIG. 2).

  Further, the branching / merging portion construction method of the present embodiment approaches the main shield tunnel 11 so that the branching / merging shield machine 13 is obliquely rubbed at a gentle angle corresponding to the road alignment in the branch / merging shield tunnel 12. Then, the cutter plate 13a of the branch / merging shield tunneling machine 13 cuts the segment 14 constituting the tunnel outer body 15 of the main shield tunnel 11 while cutting the joint side part 12a of the branch / merging shield tunnel 12 of the main shield tunnel 11. The main line shield tunnel 11 is communicated with the branching / merging shield tunnel 12 through a process of biting into the joint side surface portion 11a (see FIG. 3).

  Here, according to the present embodiment, the branch / merging portion 10 between the main shield tunnel 11 and the branch / merging shield tunnel 12 is obtained by cutting the tunnel outer body 15 of the main shield tunnel 11 by the branch / merging shield tunneling machine 13. The junction side surface portion 11a of the shield tunnel 11 and the junction side portion 12a of the branching / merging shield tunnel 12 are portions that intersect or overlap each other. In addition, according to the present embodiment, the branching / merging shield machine 13 is provided in advance so as to ensure a distance necessary to join the road alignment in the branching / merging shield tunnel 12 to the road alignment in the main shield tunnel 11. After the excavation work of the branch junction 10 with a predetermined length set, for example, it is buried at the end position of the excavation work, or the internal machine or equipment is removed leaving the skin plate and branched It is used as a part of the tunnel outer body 16 of the merge shield tunnel 12.

  And the branch merging part construction method of the shield tunnel of this embodiment joins the branch merging shield tunnel 12 to the main line shield tunnel 11, and the main part except the start end part immediately after the cutting start in the above-mentioned branch merging part 10 It is the construction method for constructing | assembling, Comprising: As shown in FIGS. 2-9, the following process a) -g) is included.

a) a step of forming the tunnel outer body 15 of the joint side surface portion 11a of the main shield tunnel 11 in the branch junction 10 using the cutting segment 14 that can be cut by the branch junction shield machine 13 (see FIG. 2);
b) A main temporary column 17 supporting a load in the vertical direction is erected on the center side of the cutting segment 14 inside the main shield tunnel 11 in the branching junction 10, and from the main temporary column 17. The step of filling and solidifying the poor compounding solidified material 18 that can be cut by the branching and merging shield machine 13 on the cutting segment 14 side (see FIG. 3),
c) While cutting the cutting segment 14 and the poorly mixed solidified material 18, the branching / merging shield machine 13 is dug, and the joining side part of the branching / merging shield tunnel 12 is joined to the joining side surface part 11 a of the main line shield tunnel 11 in the branching / merging part 10. The step of rubbing 12a (see FIG. 3),
d) An inner wall surface 19 that passes through the tunnel outer body 16 of the junction side portion 12 a of the branch junction shield tunnel 12 and is opposite to the junction side portion 11 a of the main shield tunnel 11, and the junction side portion of the branch junction shield tunnel 12 A branch merging line is installed between the inner wall surface 20 on the opposite side to 12a and a horizontal temporary support beam 21 and supports a load from above and below in the center side of the junction side part 12a of the branch merging shield tunnel 12. A step of placing the temporary intermediate pillars 22 upright and applying a ground improvement 23 to the ground around the sliding portion between the joint side surface portion 11a of the main shield tunnel 11 and the joint side portion 12a of the branch and merge shield tunnel (FIG. 4, (See Figure 5)
e) a step of removing the uncut cutting segment 17 of the joining side surface portion 12a of the main shield tunnel 11 and the tunnel outer body 16 of the joining side portion 12a of the branching and joining shield tunnel 12 (see FIG. 6);
f) Branch and merge after removing the contact surface 24a of the main shield shield 11 with the end surface 15a of the tunnel outer body 15 after removing the cutting segment 17 of the joint side surface portion 12a and the tunnel outer body 16 of the joint side portion 12a. The cutting piece 14 is removed from the connection piece 24 having the contact surface 24b with the end surface 16a of the tunnel outer body 16 of the shield tunnel 12 and the contact surface 24c with the one end surface 25a of the lateral permanent support beam 25. The exposed joint side surface portion 12a is disposed so as to cover the upper and lower ground surfaces 26, and is replaced with the horizontal temporary support beams 21, so that the contact surfaces 24c of the upper and lower connection pieces 24 and the main shield tunnel 11 are A step of laying the transverse permanent support beam 25 between the inner wall surface 19 opposite to the joint side surface portion 11a (see FIGS. 7 and 8);
g) The process of removing the main line temporary middle pillar 18 and the branch merge line temporary middle pillar 21 (refer FIG. 9).

  According to the branching / merging portion construction method of the present embodiment, in the step a) in which the tunnel outer body 15 of the joint side surface portion 11a of the main shield tunnel 11 in the branching / merging portion 10 is formed using the cutting segment 14, FIG. As shown in FIG. 2, a main shield tunnel 11 having a circular cross section having a tunnel outer diameter of, for example, about 15 m is constructed in the ground as a size capable of providing a three-lane road using various known shield machines. In this case, in the skin plate behind the shield machine, a cutting segment 14 that can be cut by the branch and merge shield machine 13 is used as a segment constituting the joint side surface portion 11a of the tunnel outer body 15 assembled in a circular ring shape. To do.

  Here, as the cutting segment 14 that can be cut by the branching and merging shield machine 13, for example, a non-metallic reinforcing fiber such as glass fiber or carbon fiber is arranged and mixed in place of a reinforcing bar, and a concrete segment or a steel plate portion is mixed. A synthetic segment filled with concrete can be used instead of a synthetic resin in which reinforcing fibers are blended. Further, the cutting segment 14 has the same shape as a general segment constituting the tunnel outer body 15 having a circular cross section, can be easily formed so as to be compatible, and the tunnel outer body 15 assembled into a circular ring shape. It can be assembled together with the other segments 27 and 28 while being arranged on the joint side surface portion 11a. In addition, as a joint member for joining and integrating the cutting segment 14 in the axial direction and the circumferential direction of the tunnel, a joint member made of a synthetic resin, for example, of a material that can be cut by the branching and joining shield machine 13 can be used. In the form, instead of such a joint member, or in addition to such a joint member, a PC steel wire 29 is used which is extended and arranged to penetrate the cutting segment 14 in the circumferential direction to tension the cutting segment 14. Thus, the cutting segment 14 is tightly and tightly integrated in the circumferential direction by the PC steel wire 29.

  That is, in this embodiment, the cutting segments 14 connected in the circumferential direction to the joint side surface portion 11a and the general material, for example, the steel segment 27 arranged adjacent thereto, continuously penetrate in the circumferential direction. A PC steel wire 29 made of, for example, a PC steel wire is inserted into the formed steel wire insertion hole, and both ends thereof are fixed in a tension state on the inner side surface of the steel segment 27 via the fixing member 30. As a result, the cutting segment 14 is firmly and tightly integrated in the circumferential direction in a stable state together with the adjacent steel segment 27. The PC steel wires 29 that tightly integrate the cutting segments 14 in the circumferential direction in this way are arranged at a pitch of, for example, about 1.5 m for each ring in the tunnel axis direction of the main shield tunnel 11. Moreover, when excavating the branch merge shield tunnel 12 while cutting the cutting segment 14 and the poor compounding solidified material 18 by the branch merge shield machine 13, the tension state of the PC steel wire 29 by the fixing member 30 is released, The excavation work is performed while smoothly removing the PC steel wire 29 from the PC steel wire 29 arranged on the rear side in the excavation direction of the branch and merge shield machine 13 so that the PC steel wire 29 does not become an obstacle to the cutting operation. To.

  In the present embodiment, the end of the horizontal temporary support beam 21 or the horizontal main support beam 25 is brought into contact with a portion of the main shield shield 11 opposite to the joint side surface portion 11 a of the tunnel outer body 15. A thick reinforcing segment 28 having a vertical inner wall surface 19 to be supported is assembled.

  The above-mentioned b) in which the main line temporary intermediate pillar 17 is erected and arranged inside the main line shield tunnel 11 in the branch junction 10 and the poor compounding solidification material 18 is filled and solidified on the cutting segment 14 side of the main line temporary intermediate pillar 17. In the process, as shown in FIG. 3, both ends are respectively joined to the upper and lower mounting bases 31 provided on the inner peripheral surface of the main shield shield 11, and the main temporary intermediate pillar 17 made of, for example, H-shaped steel is provided. Install in an upright position. In this embodiment, a pair of main line temporary intermediate pillars 17 are arranged on both sides of the center line in the cross-sectional direction of the tunnel, and a plurality of intervals are provided in the axial direction of the main line shield tunnel 11 at a pitch of, for example, about 1.5 m. Will be placed. Further, after the solid material filling formwork is attached to the joining side surface part 11a side surface of the main temporary temporary middle column 18 on the joining side surface part 11a side and the solidifying material filling formwork is attached, In a space surrounded by the inner surface, a poor blended solidifying material 18 made of a poor blended mortar that can be cut by, for example, the branch and merge shield machine 13 is placed and solidified.

  The main line temporary intermediate pillar 17 erected and arranged inside the main line shield tunnel 11 effectively supports the vertical load due to earth pressure and water pressure applied to the main line shield tunnel 11, and joins the main line shield tunnel 11. Even when the side surface portion 11a is cut and a cross-sectional defect occurs, the tunnel shape of the main shield tunnel 11 is firmly and stably maintained. Further, the poorly mixed solidified material 18 filled and solidified on the cutting segment 14 side with respect to the main line temporary intermediate pillar 17 also holds the tunnel shape firmly and stably when the joint side surface portion 11a of the main line shield tunnel 11 is cut. In addition to exhibiting the function to perform, the sand and groundwater is effectively prevented from flowing into the inside of the main shield tunnel 11 from the gap generated when the joining side surface portion 11a is cut by the branch and merge shield machine 13.

  While cutting the cutting segment 14 and the poorly mixed solidified material 18, the branching / merging shield machine 13 is dug, and the joining side part 12 a of the branching / merging shield tunnel 12 is joined to the joining side surface part 11 a of the main shield tunnel 11 in the branching / merging part 10. In the step c) of rubbing, as shown in FIGS. 1 and 3, a shield tunnel having a substantially oval cross section is preferably formed as the branching / merging shield machine 13 so that the length of the major axis can be adjusted. A shield machine with a mechanism can be used. As the branching / merging shield machine 13 having such a mechanism, for example, a shield machine described in JP-A-2001-317292 can be used.

  In the shield machine described in Japanese Patent Laid-Open No. 2001-317292, for example, a revolution support body is rotatably disposed around the shield axis at the front part of the shield body, and the revolution support body includes a shield axis and A cutter rotation shaft that is parallel and offset by a predetermined distance from the ellipse shield axis is rotatably arranged, and the cutter head provided at the front of the cutter rotation shaft swells at the apex position of the triangle with the top portion being a luro in front view. The shape is to be extended, and the normal part and the extended part of the tunnel can be continuously excavated. In addition, the revolving support is fixed at a predetermined position when excavating the normal part, and the cutter rotation shaft is driven to rotate to excavate a tunnel having a circular cross section. When the extended part is excavated, the revolving support and the cutter rotate. A shield tunnel having an elliptical cross section or a substantially oval cross section is excavated by rotationally driving the shaft in the same direction so that the rotational speed ratio is 3: 1.

  As the branching and merging shield machine 13, a shield tunnel having a substantially oval cross-sectional shape is rubbed against the main road in the main shield tunnel 11 by using a shield machine having a mechanism for adjusting the length of the long axis. It is possible to perform excavation work by the efficient branch / merging shield machine 13 along the road alignment of the road in the branch / merging shield tunnel 12. In addition, according to the present embodiment, the corner portion from the upper and lower straight portions to the curved portion on the main shield tunnel 11 side in the substantially oval cross section of the branch and merge shield tunnel 12 is the joint side surface portion of the main shield tunnel 11. The branching / merging shield tunnel 12 is formed so as to overlap the main shield tunnel 11 in such a positional relationship as to be disposed at the intersection with 11a. Thus, the main body lining 35 of the tunnel united over the main shield tunnel 11 and the branch merging shield tunnel 12 by constructing the transverse main support beams 25 via the steel connection pieces 24 (FIG. 9), the main body lining 35 can be formed efficiently and in a more stable state.

  A horizontal temporary support beam 21 is installed through the tunnel outer body 16 of the junction side portion 12a of the branch / merge shield tunnel 12, and a branch / merge line temporary intermediate column 22 is erected inside the branch / merge shield tunnel 12. In the step d) in which the ground improvement 23 is applied to the ground around the sliding portion between the main shield tunnel 11 and the branch / merging shield tunnel 12, as shown in FIGS. 4 and 5, the main shield tunnel 11 or the branch is provided. By the work from the inside of the merge shield tunnel 12, the support beam is formed on the tunnel outer body 16 at the junction side portion 12a of the branch merge shield tunnel 12 in two upper and lower stages and at a pitch of, for example, about 1.5 m in the tunnel axial direction. The through hole 34 is formed with a plurality of intervals, and a solid material filling form frame and a portion corresponding to the support beam through hole 34 are formed. To remove the poor compounding solidifying material 18.

  After that, the transverse temporary support beam 21 made of, for example, H-shaped steel is inserted into the support beam through hole 34 while being appropriately joined by welding or the like, and the inner wall surface 19 of the main shield tunnel 11 and the inner wall of the branch merge shield tunnel 12 are inserted. Both end portions are joined to the mounting base 32 provided on the wall surface 20 and installed so as to extend substantially horizontally across the inner wall surfaces 19 and 20. Also, the upper and lower ends are joined to the upper and lower mounting bases 33 provided on the inner peripheral surface of the branch / merged shield tunnel 12, and the branch / merged line temporary intermediate pillar 22 made of, for example, H-shaped steel is connected to the tunnel. Attached in a standing state at a plurality of intervals at a pitch of about 1.5 m in the axial direction, for example. Further, the ground is improved by, for example, a known freeze-stop construction so as to cover the uncut cutting segment 17 of the joint side surface portion 11a on the ground around the sliding portion between the main shield tunnel 11 and the branch / merging shield tunnel 12. 23 is applied.

  The horizontal temporary support beam 21 installed across the inner wall surface 19 of the main shield tunnel 11 and the inner wall surface 20 of the branch / merging shield tunnel 12 is rubbed into the main shield tunnel 11 and the branch / merging shield tunnel 12 integrated. Even when the uncut cutting segment 17 of the joint side surface portion 12a of the main shield tunnel 11 is removed by effectively supporting the lateral load due to the earth pressure and water pressure applied, the tunnel shape is strong and stable. Will be held. In addition, the branch / merging line temporary middle column 22 erected and arranged inside the branch / merging shield tunnel 12 effectively supports a vertical load due to earth pressure or water pressure applied to the branch / merging shield tunnel 12, Even when the junction side portion 12a of the branching / merging shield tunnel 12 is removed and a cross-sectional defect occurs, the tunnel shape of the branching / merging shield tunnel 12 is firmly and stably maintained. Further, the ground improvement 23 applied to the ground around the portion where the main shield tunnel 11 and the branching / merging shield tunnel 12 are slid is formed by removing the uncut cutting segment 17 and removing the joint side surface portion 12a of the main shield tunnel 11. When the natural ground is exposed, it will effectively prevent the exposed natural ground from collapsing and the inflow of groundwater.

  In the step e) for removing the uncut cutting segment 17 of the joint side surface portion 12a of the main shield shield 11 and the tunnel outer body 16 of the joint side portion 12a of the branch and merge shield tunnel 12, as shown in FIG. By the work from the inside of the shield tunnel 11 or the branching / merging shield tunnel 12, the cutting segment 17 and the tunnel outer body 16 at the rubbing portion can be easily removed. That is, for example, after removing the solidification material filling form and the poor compounding solidification material 18, the uncut cutting segment 17 of the joint side surface portion 12 a is removed, and the tunnel outer body of the joint side portion 12 a of the branch joint shield tunnel 12 is removed. 16 is demolished. During such work, the tunnels 11 and 12 and the ground around them are in a strong and stable state by the temporary main pillar 17, the temporary support beam 21 in the lateral direction, the temporary branching junction 22, the ground improvement 23, etc. Since it is reinforced, these removal operations can be performed safely and smoothly.

  For example, a steel connection piece 24 having predetermined contact surfaces 24a, 24b, and 24c is disposed so as to cover the upper and lower ground surfaces 26 of the exposed joint side surface portion 12a, and placed on the lateral temporary support beam 21. As described above, the horizontal main support beams 25 are respectively installed between the contact surface 24c of the connection piece 24 and the inner wall surface 19 on the opposite side to the joint side surface portion 11a of the main shield tunnel 11 in the above-mentioned f). In the process, as shown in FIGS. 7 and 8, the contact surface 24a with the end surface 15a of the tunnel outer body 15 of the main shield tunnel 11 after removing the cutting segment 17, and the tunnel outer body 16 of the joining side portion 12a are formed. A contact surface 24b with the end surface 16a of the tunnel outer body 16 of the branch and merge shield tunnel 12 after the removal, and a contact surface 24c with the one end surface 25a of the transverse permanent support beam 25, One uses the arcuate natural ground steel connecting piece 24 having a contact surface 24d. The connection piece 24 is formed to have a length of, for example, about 1.5 m in the tunnel axis direction, and from the upstream side of the branching and joining shield machine 13 in the digging direction, for example, every 1.5 m construction pitch. Then, the tunnel outer body 16 of the cutting segment 17 and the joining side portion 12a is removed and replaced with the horizontal temporary support beam 21 to construct the horizontal permanent support beam 25 sequentially.

  In the step of installing the horizontal main support beam 25 instead of the horizontal temporary support beam 21, first, the connection piece 24 is brought into close contact with the natural ground contact surface 24d and the contact surface 24a is connected to the main line. Cutting is performed so as to cover the ground surface 26 in a state where the end surface 15a of the tunnel outer body 15 of the shield tunnel 11 is in contact with the end surface 15a of the tunnel outer body 15 and the end surface 16a of the tunnel outer body 16 of the branching and joining shield tunnel 12 is in contact. The segment 17 is attached to the removed joint side surface portion 12a. As a result, the tunnel outer body 15 of the main shield tunnel 11 and the tunnel outer body 16 of the branching / merging shield tunnel 12 are firmly joined and integrated via the connection piece 24, and the transverse main support beam 25 is thus integrated. Or, it becomes possible to remove a part of the main line temporary intermediate pillar 17 as needed. In the present embodiment, out of the pair of main line temporary middle columns 17 in the cross-sectional direction of the tunnel, the main line temporary middle columns 17 on the branching and merging shield tunnel 12 side are removed.

  When the connection piece 24 is attached and the horizontal direction permanent support beam 25 is removed, the horizontal direction permanent support beam 25 is installed between the contact surface 24 c of the connection piece 24 and the inner wall surface 19 of the main shield tunnel 11. In the present embodiment, the transverse main support beam 25 includes a steel piece portion 25 b and a concrete portion 25 c, and the one end surface 25 a of the steel piece portion 25 b is used as a joint surface with the contact surface 24 c of the connection piece 24. The steel piece portion 25b is attached. Moreover, between the other end surface of the steel piece portion 25b and the inner wall surface 19 of the main line shield tunnel 11, by placing the remaining main line temporary intermediate pillars 17 partially, cast in-situ concrete. A concrete portion 25c is formed. By forming a part of the horizontal direction permanent support beam 25 with the cast-in-place concrete, the horizontal direction permanent support beam 25 can be easily aligned in the field.

  In this way, the connecting piece 24 is interposed in the sliding portion to join the tunnel outer body 15 of the main shield tunnel 11, the tunnel outer body 16 of the branching and converging shield tunnel 12, and the laterally-maintained support beam 25. By integrating, a strong and stable main body covering 35 of the branch / merging portion 10 in the branch / merging portion 10 that can support the earth pressure and water pressure from the surrounding ground with good balance is formed. .

  Further, in the step g) for removing the main line temporary intermediate pillar 18 and the branch merge line temporary intermediate pillar 21, as shown in FIG. 9, as shown in FIG. 9, the inside of the tunnel firmly supporting the load from the surrounding ground by the body lining 35. As a result, the main temporary intermediate pillar 17 excluding the part where the branch and merging line temporary intermediate pillar 22 and the portion caught in the concrete portion 25c are removed is removed, and if necessary, the ground improvement 23 due to water freeze is thawed. The construction of the main part of the branch junction 10 is completed. In addition, paving work, interior lining work, and the like are appropriately performed inside the constructed main body lining 35.

  And according to this embodiment, the junction side part 11a of the main line tunnel 11 is directly cut by the branch and merging shield machine 13 by forming the branch and junction part 10 according to the above-described steps a) to g). In the construction method for forming the branching / merging portion 10 between the shield tunnel 11 and the branching / merging shield tunnel 12, the main line is temporarily installed until the main body lining 35 is applied after the joint side surface portion 11 a of the main tunnel 11 is cut. While effectively supporting the earth pressure and water pressure from the surrounding ground stably by the pillar 17, the horizontal temporary support beam 21, the branch merging line temporary middle pillar 22, the ground improvement 23, etc., the branch merging section 10 is efficiently supported. It becomes possible to perform construction.

  The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, it is not always necessary to use a PC steel wire as a means for connecting cutting segments in the circumferential direction, and a shield machine with a substantially oval cross-sectional shape capable of adjusting the length of the major axis is used as a branch / merge shield machine. It is not always necessary to use it. Further, the main shield tunnel may be a shield tunnel having an elliptical cross section or a substantially rectangular cross section other than a circular cross section, and the branching / merging shield tunnel is also a circular cross section or an elliptic cross section other than a substantially oval cross section. A shield tunnel having a cross-sectional shape of Further, the main shield tunnel and the branch / merging shield tunnel forming the branch / merging portion may be, for example, a subway tunnel or a sewer tunnel other than the road tunnel.

It is a plane sectional view explaining the branch merge part formed by the branch merge part construction method of the shield tunnel which concerns on preferable one Embodiment of this invention. It is sectional drawing in alignment with the AA of FIG. 1 explaining the process of the branch merge part construction method of the shield tunnel which concerns on preferable one Embodiment of this invention. It is sectional drawing in alignment with the BB of FIG. 1 explaining the process of the branch merging part construction method of the shield tunnel which concerns on preferable one Embodiment of this invention. It is sectional drawing in alignment with the BB of FIG. 1 explaining the process of the branch merging part construction method of the shield tunnel which concerns on preferable one Embodiment of this invention. It is sectional drawing in alignment with the BB of FIG. 1 explaining the process of the branch merging part construction method of the shield tunnel which concerns on preferable one Embodiment of this invention. It is sectional drawing in alignment with the BB of FIG. 1 explaining the process of the branch merging part construction method of the shield tunnel which concerns on preferable one Embodiment of this invention. It is sectional drawing in alignment with the BB of FIG. 1 explaining the process of the branch merging part construction method of the shield tunnel which concerns on preferable one Embodiment of this invention. It is sectional drawing in alignment with the BB of FIG. 1 explaining the process of the branch merging part construction method of the shield tunnel which concerns on preferable one Embodiment of this invention. It is sectional drawing in alignment with the BB of FIG. 1 explaining the process of the branch merging part construction method of the shield tunnel which concerns on preferable one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Junction junction 11 Main shield tunnel 11a Junction side surface part 12 of main shield tunnel 12 Junction shield tunnel 12a Junction shield tunnel 13a Branch junction shield machine 14 Cutting segment 15 Tunnel outline 15a of main shield tunnel End 16 of tunnel 16 Tunnel outer body 17 of main junction shield 18 Main mix temporary column 18 Poorly mixed solidified material 19 Inner wall 20 on the opposite side of the main shield tunnel junction side 20 Opposite to the junction side of the junction junction shield tunnel Side inner wall 21 Transverse support beam 22 Branch / merging line temporary middle pillar 23 Ground improvement 24 Connecting piece 24a Contact surface 24b of connecting piece main tunnel shield end face of tunnel outer shell of connecting piece branch / merging shield tunnel End face of tunnel shell Contact surface 24c of the connecting piece Abutment surface 25 of the connecting piece with one end surface of the transverse permanent support beam Lateral permanent support beam 25a One end surface 25b of the transverse permanent support beam Steel piece of the transverse permanent support beam Part 25c Concrete part 26 of transverse direction support beam Joint ground surface 27 of joint side part Steel segment 28 Reinforcement segment 29 PC steel wire 30 Fixing member 35 Body lining

Claims (3)

A method for constructing a branching / merging part of a shield tunnel in which a branching / merging shield tunnel is joined to a main line shield tunnel to form a branching / merging part of the tunnel,
Forming a tunnel outer body of the joint side surface portion of the main shield tunnel in the branch merge section using a cutting segment that can be cut by a branch merge shield machine;
A main temporary middle pillar that supports a load from above and below is erected on the center side of the cutting segment inside the main shield tunnel at the branching junction, and the cutting segment is more than the main temporary middle pillar. Filling and solidifying the poor blend solidified material that can be cut by the branching and merging shield machine on the side;
While cutting the cutting segment and the poor compounding solidified material, the branch merging shield tunneling machine is dug, and the joint side portion of the branch merging shield tunnel is slid onto the joint side surface portion of the main shield tunnel in the branch merging portion. Process,
An inner wall surface on the opposite side to the junction side portion of the main shield tunnel, and an inner side on the opposite side to the junction side portion of the branch and merge shield tunnel, through the tunnel outer body on the junction side portion of the branch and merge shield tunnel A horizontal temporary support beam is installed between the wall surface and a branch / merging line temporary middle column that supports a load from the vertical direction on the center side of the junction side portion of the branch / merging shield tunnel; and A step of performing ground improvement on the ground around the sliding side portion between the joint side portion of the main shield tunnel and the joint side portion of the branch and merge shield tunnel;
Removing the uncut cutting segments of the joint side surface portion of the main shield tunnel and the tunnel outer body of the joint side portion of the branch and merge shield tunnel; and
The contact surface with the end face of the tunnel outer body of the main shield tunnel after removing the cutting segment of the joint side surface part, and the tunnel outer body of the branch and merge shield tunnel after removing the tunnel outer body of the joint side part A connecting piece having a contact surface with the end surface of the metal plate and a contact surface with the lateral support beam is disposed so as to cover the ground surfaces above and below the joint side surface exposed by removing the cutting segment. At the same time, the horizontal permanent support beam is replaced between the contact surface of the upper and lower connection pieces and the inner wall surface on the opposite side to the joint side surface portion of the main shield tunnel so as to replace the horizontal temporary support beam. Installing each beam; and
A branch merging portion construction method for a shield tunnel, including a step of removing the main line temporary middle pillar and the branch merging line temporary middle pillar.   The PC, which is assembled in a state in which the cutting segment is tensioned in the circumferential direction by a PC steel wire extending and arranged to penetrate in the circumferential direction, and arranged on the rear side in the digging direction of the branching and merging shield machine The method for constructing a branching / merging portion of a shield tunnel according to claim 1, wherein the branching / merging shield machine is excavated from the steel wire to cut the cutting segment and the poor blended solidified material. The branching and merging of shield tunnels according to claim 1 or 2, wherein the branching and merging shield machine is a shield machine having a mechanism for forming a shield tunnel having a substantially oval cross section so that the length of the major axis can be adjusted. Part construction method.

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