JP4948466B2 - Assembly method of inner formwork - Google Patents

Description

  The present invention relates to an inner frame assembling method capable of correcting a leading ring joint surface when the leading ring joint surface is no longer a plane orthogonal to the excavation progress direction.

Conventionally, excavated by excavating natural ground with a shield excavator, along the inner peripheral surface of the tunnel cavity portion and the inner peripheral surface of the tunnel cavity portion formed by the excavation hole in the rear portion (wellhead side) of the shield excavator A tunnel construction method called an ECL method is known in which fluid concrete called ready-mixed concrete is poured into an installed inner form to construct lining concrete as a lining part (for example, Patent Document 1). reference).
The inner mold is formed by a plurality of mold pieces. As shown in FIGS. 5 and 6, the plurality of mold pieces 40 forming the inner mold frame 30 are arranged along the inner circumferential surface 33 of the tunnel cavity portion 21 formed by the excavation hole excavating the natural ground 20. In order to connect the mold surface 34 installed so as to be opposed to the surface 33 with an interval, and the mold pieces 40; 40 installed adjacent to each other in the circumferential direction of the inner peripheral surface 33 of the tunnel cavity 21. A ring for connecting the formwork pieces 40; 40 that are provided so as to be adjacent to each other in the direction of excavation of the inner peripheral surface 33 of the tunnel cavity 21. A ring joint plate 46 having a joint surface 47b is provided.
The piece joint plate 45 is connected to the piece joint plate 45 so that the piece joint surfaces 47a adjacent to each other in the circumferential direction of the inner peripheral surface 33 of the tunnel cavity 21 are closely coupled by fastening with bolts and nuts not shown. Bolt holes 43a for passing bolts through 45 are formed. Similarly, the ring joint plate 46 is connected so that the ring joint surfaces 47b adjacent to each other in the direction of excavation of the inner peripheral surface 33 of the tunnel cavity portion 21 are in close contact with each other by fastening with bolts and nuts. Bolt holes 43b are formed through which the bolts pass through 46.
Accordingly, a bolt (not shown) is inserted into the bolt hole 43a in a state where the piece joint surfaces 47a of the mold pieces 40 installed adjacent to each other in the circumferential direction of the inner peripheral surface 33 of the tunnel cavity portion 21 are in contact with each other. By fastening the nut from the tip of the bolt, the piece joint surfaces 47a are coupled in a close state. Further, a bolt (not shown) is inserted into the bolt hole 43b in a state where the ring joint surfaces 47b of the formwork pieces 40 installed adjacent to each other in the tunnel excavation traveling direction of the inner peripheral surface 33 of the tunnel cavity portion 21 are in contact with each other. Then, by tightening the nut from the tip of the bolt, the ring joint surfaces 47b are coupled in close contact.
As shown in FIG. 6, the inner mold 30 formed by installing a plurality of mold pieces 40 so as to make one round along the inner circumferential surface 33 of the tunnel cavity 21 is called one ring. That is, in order to form one ring, the plurality of mold pieces 40 are separated from the inner peripheral surface 33 of the tunnel cavity portion 21 by an interval d corresponding to the thickness of the lining portion. The inner circumferential surface 33 is installed so as to make one round along the inner circumferential surface 33. In this case, the inner mold 30 for one ring is assembled by an inner mold assembling apparatus (not shown) so that the piece joint surfaces 47a are closely coupled to each other. Then, after the excavation progresses, the inner mold 30 for one ring is further assembled in the excavation progress direction. In this case, the mold piece 40 is excavated so that the piece joint surfaces 47a are in close contact with each other in the circumferential direction of the inner peripheral surface 33 of the tunnel cavity 21 and the inner peripheral surface 33 of the tunnel cavity 21 is excavated. By the inner mold assembly apparatus, the ring joint surface 47b of the first ring assembled in the advancing direction and the ring joint surface 47b of the mold piece 40 forming the one ring to be assembled this time are closely coupled. The inner mold 30 for one ring is assembled.
The mold piece 40 is used as many as the number of inner molds 30 corresponding to a predetermined number of rings, and after the inner molds 30 corresponding to the predetermined number of rings are installed, the inner mold frame assembled on the wellhead side is used. After the mold piece 40 for one ring located at the rear of the excavation direction 30 is disassembled and removed using an inner mold removal device (not shown), the shield excavator is advanced to remove one ring. The formwork piece 40 is used after being changed to the top position of the inner formwork 30 in the direction of excavation. That is, after installing a predetermined number of inner molds 30 corresponding to the number of rings, each time excavation progresses, the mold piece 40 is repeatedly used from the rear (wellhead side) to the front (face side). One ring is assembled at the head position of the mold 30 in the direction of excavation. That is, the inner mold 30 is formed by assembling one ring at a time in the direction of excavation progress.
As shown in FIG. 6, at least one of the plurality of mold pieces 40 forming the inner mold 30 for one ring is formed on the mold piece 39 for demolding. . A demolding mold piece 39 called a K mold piece is positioned nearer to the inner peripheral surface 33 of the tunnel cavity 21 and forms a mold surface 34 on the side of the tunnel cavity 21 on the mold surface 34 side. The width dimension b in the circumferential direction is smaller than the width dimension a in the circumferential direction of the tunnel cavity portion 21 on the surface 39b on the opposite side of the mold surface 34 (the surface located closer to the center 2C of the tunnel cavity portion 21). In addition, a dedicated formwork piece 38 is also used as the formwork piece installed on both sides in the circumferential direction of the formwork piece 39 for demolding. The mold piece 40 called A mold piece other than the mold piece 39 and the mold piece 38 for forming the inner mold 30 for one ring is closer to the inner peripheral surface 33 of the tunnel cavity 21. The width dimension b in the circumferential direction of the tunnel cavity 21 on the mold surface 34 side which is located at the mold surface 34 is the width in the circumferential direction of the tunnel cavity 21 on the surface 39 b on the opposite side of the mold surface 34. It is larger than the dimension a. And when assembling one ring, the mold piece 39 for mold removal is attached lastly, and when disassembling one ring, it removes from the mold piece 39 for mold removal. That is, even if one ring is assembled using only the formwork piece 40 called A formwork piece, the last formwork piece 40 is moved from the center 2C side of the tunnel cavity 21 to the inner peripheral surface 33 of the tunnel cavity 21. Since it is impossible to assemble it toward the direction (that is, toward the radial direction of the cross-sectional circle of the tunnel cavity 21), the mold piece that is assembled last and removed first is called a K-shaped frame piece. The formwork piece 39 is used.
JP 2005-188099 A

As described above, each time excavation proceeds, the mold piece 40 is rearranged from the rear side (wellhead side) to the front side (face side) and repeatedly used, and one ring is placed at the head position in the excavation progress direction of the inner mold frame 30. Assemble. In other words, in order to repeat the assembly and demolding of the ring, the assembly position of the inner mold 30 is affected by the pressure applied from the natural ground 20, the arrangement of the propulsion jack, the distortion of the inner mold 30 and the like. There are cases where errors accumulate and the assembly posture of the inner mold 30 is shifted, and the leading ring joint surface 47b of the ring-shaped inner mold 30 located on the face side is not a plane orthogonal to the excavation progress direction. . When the leading ring joint surface 47b is no longer a plane orthogonal to the excavation progress direction, the leading ring joint surface 47b and the ring joint surface 47b of the next inner mold frame 30 joined to the leading ring joint surface 47b Since the gap generated between the bolts and the nut becomes large, it is impossible to obtain the fastening frictional force between the bolt and the nut, and the nut is easily loosened. Further, the distance between the mold surface 34 of the inner mold 30 and the inner peripheral surface 33 of the tunnel cavity 21 is different between the upper and lower sides of the inner mold 30 and the left and right sides of the inner mold 30. That is, the distance between the upper and lower mold surfaces 34 of the inner mold 30 and the inner peripheral surface 33 of the tunnel cavity 21 and the inner periphery of the left and right mold surfaces 34 of the inner mold 30 and the tunnel cavity 21. There is a problem in that the gap between the surface 33 and the surface 33 is uneven, and the thickness is uneven in the circumferential direction of the primary lining concrete formed in the space (lining forming space).
Therefore, the present invention provides a method of correcting the leading ring joint surface when the leading ring joint surface is no longer a plane orthogonal to the excavation progress direction.

The method of assembling the inner mold according to the present invention includes a lining portion that is installed along an inner peripheral surface of a tunnel cavity formed by an excavation hole excavated from a natural ground and between the inner peripheral surface of the tunnel cavity. A plurality of the mold pieces of the inner mold for forming the inner mold form are installed so as to make one round of the inner circumference along the inner circumference of the tunnel cavity, thereby forming a ring-shaped inner mold, In the method of assembling the inner mold that sequentially assembles the inner mold toward the direction of excavation, the top ring joint surface of the ring-shaped inner mold located on the face side is no longer a plane that is orthogonal to the direction of excavation In this case, the correction ring joint surface is corrected by using a correction part having a predetermined thickness so that the leading ring joint surface becomes a plane orthogonal to the excavation progress direction or approaches the plane. Features.
The difference between the average value of the strokes of the upper and lower propulsion jacks of the shield excavator and the average value of the strokes of the left and right shield jacks, which takes a reaction force at the top ring joint surface of the ring-shaped inner mold located on the face side, is predetermined It is also characterized by correcting the leading ring joint surface when the value exceeds the value.

According to the method for assembling the inner mold according to the present invention, when the leading ring joint surface is not a plane orthogonal to the excavation progress direction, the leading ring joint surface is orthogonal to the excavation progress direction using the correction part. Since the correction ring joint surface corrected so as to become a flat surface or close to the plane can be formed, the correction ring joint surface and the ring joint surface of the next inner form frame joined to the correction ring joint surface are in close contact with each other. The ring joint surfaces can be sufficiently joined to each other, and the fastening frictional force by the bolts and nuts for joining the ring joint surfaces can be sufficiently obtained. Moreover, the thickness deviation can be reduced in the circumferential direction of the primary lining concrete formed in the lining forming space, and the quality of the primary lining concrete can be improved. Furthermore, the correction work is simple because only correction parts are used.
The difference between the average value of the strokes of the upper and lower propulsion jacks of the shield excavator and the average value of the strokes of the left and right shield jacks, which takes a reaction force at the top ring joint surface of the ring-shaped inner mold located on the face side, is predetermined When the value exceeds the value, the leading ring joint surface is corrected, so that the necessity of the correction work can be accurately determined.

  1 to 4 show the best mode, FIG. 1 shows an outline of an inner mold assembly method, and FIG. 2 (a) shows a ring joint surface of the leading inner mold frame in the inner mold assembly method. FIG. 3 shows a tunnel construction method using a sealed shield excavator, and FIG. 4 is formed on a concrete supply pipe and a wife formwork. The relationship with the concrete placement hole is shown.

  In the best mode, as shown in FIG. 1, for example, a plurality of metal mold pieces 40 are installed along the inner peripheral surface 33 of the tunnel cavity 21 so as to make one round of the inner peripheral surface 33. In the case of sequentially assembling the ring-shaped inner mold 30 in the direction of excavation, for example, each time the assembly of the inner mold 30 for a plurality of rings (for example, 16 rings) is completed, the leading ring joint The average value of the stroke of the propulsion jack 4 (the amount of extension of the piston 4a of the propulsion jack 4) and the shield excavator 1 provided above and below the rear end 1a of the shield excavator 1 propelled by taking the propulsion reaction force on the surface 47b. The difference with the average value of the stroke of the propulsion jack 4 provided in the right and left of the rear end part 1a is measured. If the difference is equal to or greater than a predetermined value, the leading ring joint surface 47b is no longer a plane orthogonal to the excavation traveling direction A. As shown in FIG. Is attached to the leading ring joint surface 47b to form a correction ring joint surface 52 that is corrected so as to be close to the plane orthogonal to the excavation traveling direction A or to the correction ring joint surface 52. The ring joint surface 47b of the mold piece 40 forming the next ring-shaped inner mold 30 is continued.

  For example, 30 propulsion jacks 4 are installed at a predetermined interval in the direction along the inner peripheral surface 33 of the tunnel cavity 21. Among these, the difference between the average value of the strokes of the two propulsion jacks 4 provided above and below and the average value of the strokes of the two propulsion jacks 4 provided on the left and right are measured. By measuring the difference, it is possible to accurately determine the necessity of the correction work.

  When the excavation traveling direction A is a straight traveling direction, the predetermined value may be set to 30 mm or more, for example. The difference of 30 mm or more means that the gap between the leading ring joint surface 47b and the ring joint surface 47b of the next ring-shaped inner mold frame 30 becomes large, and is formed in the lining forming space 100. This is because the thickness deviation also increases in the circumferential direction of the primary lining concrete 90. If the predetermined value is 30 mm or more, by performing the correction work using the stroke adjustment liner 50, the leading ring joint surface 47b becomes a plane orthogonal to the excavation traveling direction A or approaches the plane. The corrected correction ring joint surface 52 can be formed.

  As shown in FIG. 2, the stroke adjustment liner 50 includes a wellhead side surface 53, a face side surface 54, and a bolt hole 55 that penetrates the wellhead side surface 53 and the face side surface 54. For example, the area of the wellhead side surface 53 and the area of the face side surface 54 are formed to be the same as the area of the ring joint surface 47 b of the mold piece 40 that forms the leading ring joint surface 51. The wellhead side surface 53 is formed on a surface that matches the leading ring joint surface 51 that is no longer a plane orthogonal to the excavation traveling direction A. The face side surface 54 forms the correction ring joint surface 52 when the leading ring joint surface 47b and the wellhead side surface 53 are joined in a closely matched state. That is, the stroke adjusting liner 50 is formed so that the face side surface 54 can form the correction ring joint surface 51 when the leading ring joint surface 47b and the well side surface 53 are joined in a closely matched state. This is a correction component in which the distance (thickness) e between the face and the face side 54 is adjusted. Specifically, as shown in FIG. 2B, the stroke adjustment liner 50 is formed such that the distance e (thickness) is different from one side 60 to the other side 61 in the radial direction, and one side in the circumferential direction. The correction parts are formed differently from 62 to the other 65.

  The stroke adjusting liner 50 is attached, for example, by sandwiching the stroke adjusting liner 50 between the leading ring joint surface 47b and the ring joint surface 47b of the mold piece 40 that forms the next ring-shaped inner mold frame 30. Then, these three members may be fixed with bolts and nuts not shown. As described above, the correction work can be easily performed only by attaching the stroke adjusting liner 50 as the correction part to the leading ring joint surface 47b.

Next, a tunnel construction method using a sealed shield excavator using the formwork piece 40 and the structure of the shield excavator will be described with reference to FIGS.
First, the structure of the shield excavator 1 will be described. The shield excavator 1 has a rotary cutting part 2 at a front end, and a rear end of the rotary cutting part 2 includes a cylindrical tail plate 3 extending rearward. A plurality of propulsion jacks 4, a press jack 5, and a wife formwork 7 are provided inside the tail plate 3. The end form frame 7 is a press form frame that is attached to the rear end 5a of the press jack 5 and formed in a ring tube shape so as to be movable back and forth along the inner peripheral surface 3a of the tail plate 3. That is, the wife mold 7 is a mold that can be moved back and forth by expansion and contraction of the press jack 5 in a state where the space between the inner peripheral surface 3a of the tail plate 3 and the mold surface 34 of the inner mold 30 is closed. While forming the lining formation space 100 mentioned later, the highly fluid ready-mixed concrete 80 which flowed into the lining formation space 100 is pressurized. A concrete supply device 8 is pulled by a pulling means (not shown) as the shield excavator 1 is propelled. The concrete supply device 8 includes, for example, one remixer 81 that generates high-fluidity ready-mixed concrete 80 and six concrete pumps 83 connected to the remixer 81 by connection pipes 82.

  The form frame 7 is installed on the face side of the inner form 30 and is formed in a ring shape along the inner peripheral surface 33 of the tunnel cavity 21. The form form surface is formed by one end face of the ring at the wellhead 22 side. 7a and a pressure receiving surface 7b formed by the other end surface on the face side of the ring and pressed by the press jack 5, and penetrated through the mold frame surface 7a and the pressure receiving surface 7b, and spaced in the circumferential direction of the ring of the wife mold frame 7 And a plurality of concrete placement holes 9 provided with a gap therebetween.

  As shown in FIG. 4, for example, twelve concrete placement holes 9 penetrating the mold surface 7 a and the pressure receiving surface 7 b are formed in the end frame 7 at equal intervals in the circumferential direction. A first concrete supply hose 11 is connected to the concrete discharge port 10 of each concrete pump 83, and a two-way switching valve 12 is connected to the end of the hose 11, and the two discharge ports 13 of the two-way switching valve 12; 13 and one concrete placing hole 9 are connected by a second concrete supply hose 14; 14. A closing valve device 15 such as a hydraulic cylinder piston is provided on the end side of the second concrete supply hose 14. The blocking valve 15a of the blocking valve device 15 moves back and forth in the connection pipe 14a that connects the second concrete supply hose 14 and the placement hole 9 to open and close the connection pipe 14a. An in-pipe pressure gauge 16 for measuring the in-pipe pressure in the second concrete supply hose 14 is provided on the end side of the second concrete supply hose 14 near the connection pipe 14a. In addition, the lining forming space 100 was filled in the vicinity of each of the twelve placement holes 9 in the formwork surface 7a of the wife formwork 7 or in the vicinity of at least one of the twelve placement holes 9. A concrete pressure gauge 17 is provided for measuring the pressure of the ready-mixed concrete.

  Next, a tunnel construction method using the mold piece 40 will be described. First, the reaction force of the propulsion jack 4 is taken by a reaction force receiver (not shown) and the rotary cutting portion 2 is rotated while the piston 4a of the propulsion jack 4 is extended to cause the shield excavator 1 to excavate by a certain distance, and the ground (the ground) / Band) Tunnel tunnel 21 is dug. The fixed distance is, for example, the length of the tube length 31 (for example, about 1 m to 2 m) of one ring of the inner mold 30 + the front-rear length 32 of the shield excavator 1. After the shield excavator 1 has been excavated by a certain distance, the piston 4a of the propulsion jack 4 of the shield excavator 1 is shrunk, and the inner end of the propulsion jack 4 is connected to the rear end 4b of the propulsion jack 4 by an internal mold assembly device (not shown). Assemble the formwork 30. The inner mold 30 for one ring is assembled into a cylindrical shape by using a plurality of mold pieces 40 that form a part of a circular arc of the cylinder of the inner mold 30 for one ring. The formwork surface 34 of the formwork piece 40 is held by an inner formwork assembly device (not shown) so as to be along the inner peripheral surface 33 with a space between it and the circular inner peripheral surface 33 of the tunnel cavity 21. Formwork pieces 40 adjacent to each other on the circumference of the cylindrical shape are not shown in the figure so that a cylindrical inner mold 30 coaxial with the central axis of the tunnel cavity 21 is formed inside the tunnel cavity 21. Fastened with bolts and nuts. The bolt 63 that connects the adjacent mold pieces 40 is referred to as an inter-piece joint bolt. Specifically, the mold piece pieces 40 are installed adjacent to each other so that the piece joint surfaces 47a of the mold piece pieces 40 are in contact with each other, and the bolt holes 43a of the piece joint surfaces 47a of the adjacent mold frame pieces 40 are provided. When the bolt 63 is passed through and the nut 72 is fastened to the tip of the bolt 63, the mold piece 40 is connected to each other so that the piece joint surfaces 47 a are in close contact with each other. As described above, the inner mold frame 30 for one ring having a cylindrical shape is formed inside the tunnel cavity portion 21, and the circular inner peripheral surface 33 of the tunnel cavity portion 21 and the circular inner mold frame 30 for one ring are formed. A cylindrical lining forming space 100 between the mold surface 34 and the mold surface 34 is formed. The wellhead 22 side of the lining forming space 100 is closed with a block plate or the like (not shown), and the formwork surface 7a of the wife formwork 7 is moved to the front end side of the lining forming space 100, so While pouring high-fluidity ready-mixed concrete 80 pressurized by the concrete pump 83 through, for example, twelve placement holes 9 around the frame surface 7a, the press mold 5 is pressed against the end frame 7 to provide high-fluidity freshness. The concrete 80 is pressurized. Then, when the pressure of the high-fluidity ready-mixed concrete 80 poured into the lining forming space 100 becomes a predetermined value while monitoring the pressure value transmitted from the concrete pressure gauge 17 by a monitor or the like. Operates the operating portion of the blocking valve 15a to block the connection pipe 14a with the blocking valve 15a, and solidifies the high-fluidity ready-mixed concrete 80 in the lining forming space 100. Accordingly, since the six concrete pumps 83 are used and the superfluid ready-mixed concrete 80 is filled into the lining forming space 100 from the twelve placement holes 9 around the rear surface 7a of the end form frame 7, a plurality of concrete pumps are filled. Due to the pressure applied at 83, the flow of the high-fluidity ready-mixed concrete 80 from the plurality of placement holes 9 and the high-fluidity of the high-flowable ready-mixed concrete 80, the lining forming space 100 is evenly dense in a short time The lining concrete 90 can be constructed as a lining portion having a high-density structure that can be filled with the highly fluid ready-mixed concrete 80 and closely integrated with the inner peripheral surface 33 (the ground 20) of the tunnel cavity portion 21. Further, the same number of concrete pumps 83 as the number of placement holes 9 may be provided, and the high-fluidity ready-mixed concrete 80 may be placed from one placement hole 9 with one concrete pump 83, as in the embodiment. By connecting two casting holes 9 to one concrete pump 83 using the number of concrete pumps 83 that is ½ of the number of casting holes 9, the number of concrete pumps 83 can be reduced and a large number of casting holes 9. It is economical because it can be placed from Moreover, since the concrete pressure gauge 17 is provided, the pressure monitoring control of the highly fluid ready-mixed concrete 80 poured into the lining forming space 100 can be easily performed. Further, if a control device (not shown) that opens and closes the closing valve 15a by reading a signal from the concrete pressure gauge 17 is provided, the opening and closing of the closing valve 15a can be automated.

  Next, the rotary mold 2 is rotated while the piston 4a of the propulsion jack 4 is extended by using the reaction force of the propulsion jack 4 using the inner mold frame 30 left inside the lining concrete 90 as a reaction force receiver. The shield excavator 1 is advanced by a certain distance. Then, the inner mold frame 30 for the next one ring is formed on the digging progress direction A side so as to be continuous with the inner mold form 30 formed on the wellhead 22 side, and thus the front and rear along the digging progress direction A. Adjacent inner molds 30 are fastened by bolts 63 and nuts 72. Then, lining concrete 90 is formed between the mold surface 34 of the newly formed inner mold 30 and the inner peripheral surface 33 of the tunnel cavity 21.

  Thereafter, in the same manner as described above, the shield excavator 1 is excavated by a certain distance to form the inner mold 30 for one ring, and the inner mold 30 formed immediately before the formed inner mold 30 The lining concrete 90 is formed between the formwork surface 34 of the newly formed inner formwork 30 and the inner peripheral surface 33 of the tunnel cavity 21 by being connected.

  In general, since the tunnel length is a long distance, the mold piece 40 is used as many as the number of inner molds 30 for a predetermined number of rings, and the inner molds 30 for a predetermined number of rings are installed. After that, after disassembling and removing the mold piece 40 for one ring located at the rear of the excavation traveling direction A of the inner mold 30 assembled on the wellhead 22 side using an inner mold removing device not shown in the drawing. Then, the shield excavator 1 is advanced, and the removed mold piece 40 for one ring is used by changing it to the top position of the inner mold 30 in the excavation direction A. That is, after the inner molds 30 for a predetermined number of rings are installed, each time excavation progresses, the mold piece 40 is refilled from the rear side (wellhead side) to the front side (face side) and repeatedly used.

  As shown in FIG. 1A, in order to repeat the assembly and demolding of the ring, it is caused by the pressure applied from the natural ground 20, the arrangement of the propulsion jack 4, the distortion of the inner mold 30 and the like. An error in the assembly position of the inner mold 30 is accumulated, and the assembly posture of the inner mold 30 is shifted, and the ring joint surface 51 at the head of the ring-shaped inner mold 30 located on the face side is in the direction of excavation. In some cases, the plane is not perpendicular to A.

  Therefore, according to the best mode, as described above, for example, every time the assembly of the inner mold 30 for 16 rings is completed, the shield excavation is performed by propelling the thrust reaction force at the leading ring joint surface 47b. The average value of the strokes of the plurality of propulsion jacks 4 provided above and below the rear end 1a of the machine 1 and the average value of the strokes of the plurality of propulsion jacks 4 provided on the left and right of the rear end 1a of the shield excavator 1; If the difference is greater than or equal to a predetermined value, it is determined that the leading ring joint surface 47b is no longer a plane orthogonal to the excavation traveling direction A, and the stroke adjusting liner 50 is moved to the leading ring joint surface 47b. The correction ring joint surface 52 is formed by attaching, and the ring joint surface 47 b of the next ring-shaped inner mold frame 30 is joined to the correction ring joint surface 52.

  Therefore, according to the best mode, when the leading ring joint surface 47b is not a plane orthogonal to the excavation progress direction A, the ring joint surface to which the ring joint surface 47b of the next ring is joined is moved to the excavation progress direction. Since the correction ring joint surface 52 is corrected so as to be a plane orthogonal to A or close to the plane, the correction ring joint surface 52 and the next inner mold 30 connected to the correction ring joint surface 52 can be used. The ring joint surface 47b can be joined in close contact with each other, and a sufficient fastening frictional force can be obtained by the bolts and nuts connecting the correction ring joint surface 52 and the ring joint surface 47b. The ring joint surface 47b can be firmly coupled. Further, the thickness deviation in the circumferential direction of the primary lining concrete 90 formed in the lining forming space 100 can be reduced, and the quality of the primary lining concrete 90 can be improved.

  The size of the stroke adjustment liner 50 is not particularly limited as long as the stroke adjustment liner 50 forms a ring that makes one round along the inner peripheral surface 33 of the tunnel cavity 21 by the plurality of stroke adjustment liners 50.

The schematic sectional drawing which shows the assembly method of an inner mold form (best form). (A) is an exploded sectional view showing the relationship between the ring joint surface of the leading inner mold and the correction part in the inner mold assembly method, and (b) is a perspective view showing the correction part (best mode 1). Sectional drawing which shows the tunnel construction method by a sealed shield excavator (best form). The figure which shows the relationship between a concrete supply pipe and the concrete placement hole formed in the end form (the best form). The perspective view which shows a formwork piece (conventional). The figure which shows the relationship between a tunnel cavity part and an internal formwork (conventional).

Explanation of symbols

21 tunnel cavity part, 30 inner formwork, 33 inner peripheral surface, 40 formwork piece,
47b Ring joint surface, 52 Correction ring joint surface, 53 Wellhead side surface,
54 Face side, A Drilling direction.

Claims (2)

  Formwork piece of an inner frame for forming a lining portion between the inner peripheral surface of the tunnel cavity portion and the inner peripheral surface of the tunnel cavity portion that is installed along the inner peripheral surface of the tunnel cavity portion formed by the excavation hole excavated from the natural ground Are installed so as to make one round of the inner peripheral surface along the inner peripheral surface of the tunnel cavity to form a ring-shaped inner mold frame, and the ring-shaped inner mold frame is sequentially assembled in the direction of excavation progress. In the method of assembling the inner mold, the front ring joint surface of the ring-shaped inner mold located on the face side is no longer a plane perpendicular to the direction of excavation, and the front ring joint surface is excavated. A method of assembling an inner mold frame, wherein a correction ring joint surface corrected by using a correction component having a predetermined thickness is formed so as to be a plane orthogonal to the direction or approach the plane.   The difference between the average value of the strokes of the upper and lower propulsion jacks of the shield excavator and the average value of the strokes of the left and right shield jacks, which takes a reaction force at the top ring joint surface of the ring-shaped inner mold located on the face side, is predetermined. 2. The method for assembling an inner mold according to claim 1, wherein when the value becomes equal to or greater than the value, the leading ring joint surface is corrected.

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