JP2020122298A - Formwork for tunnel lining - Google Patents

Abstract

To provide formwork for tunnel lining capable of easily setting up inducing joints without much labor and time in the middle part of each construction span of tunnel lining concrete.SOLUTION: A formwork for tunnel lining 1 includes: a movable frame part 2; and a formwork body 3 that includes an upper wall 3a supported by the frame part 2 and forms a lining space S between the inner wall surface of a tunnel T and a pair of side formworks 3b connected to the lower ends of both sides of the upper formwork 3a. The frame part 2 is structured integrally, and the formwork body 3 is constituted of a pair of divided formwork bodies 3A, 3B, which is divided into two in the excavation direction X of the tunnel T. The divided formwork bodies 3A, 3B are supported by the frame part 2 so that a slit-shaped gap δ of constant width is formed on the edge between the edges adjacent thereto. A plate member 15 for forming joints in the middle of each construction span L is inserted and placed in a pull-out manner in the gap δ in a state where it projects over the entire circumference of the lining space S.SELECTED DRAWING: Figure 3

Description

The present invention relates to a tunnel lining form, and more particularly to a long span tunnel lining form used to form tunnel lining concrete that covers an inner wall surface of a tunnel in a mountain tunnel method.

For example, in the mountain tunnel method, a secondary lining is carried out by covering the inner wall surface of the mountain tunnel formed by excavating the ground with a lining concrete of a predetermined thickness. Using a tunnel lining form called slide slide that is movable along the excavation direction (front-rear direction), the following is done (for example, refer to Patent Documents 1 to 3).

That is, the tunnel lining formwork is carried into the tunnel, and a lining space of a predetermined thickness is provided between the arch-shaped formwork main body portion provided on the tunnel lining formwork and the inner wall surface of the tunnel. Is formed along the circumferential direction, and the secondary lining is carried out by supplying concrete pumped from the concrete pump to this lining space and hardening it, whereby the inner wall surface of the tunnel has a predetermined thickness. Tunnel lining covered with concrete.

With the progress of the excavation work of the tunnel, the secondary lining is moved from the rear to the front in the tunnel advancing direction while re-installing the tunnel lining formwork at every predetermined construction span of about 10.5 m. Will be carried out sequentially.

By the way, in the recent tunnel construction method, due to the progress of excavation technology, the excavation time of the face face of the tunnel has been shortened, and the process of secondary lining, specifically concrete casting to curing and tunnel lining formwork The progress of the process until demolding cannot keep up with the progress of the excavation process of the face of the tunnel.

Therefore, for example, the steps from assembling the tunnel lining formwork to placing the concrete and the steps from curing the placed concrete to removing the tunnel lining formwork on different days. What was done was to complete the process from demolding and moving the tunnel lining formwork and reassembling to placing concrete in one day, and the next day to apply it exclusively to the concrete curing period. May be implemented.

Further, as another method, instead of the generally used tunnel lining form having an extension of about 10.5 m, preferably a long span tunnel lining form having an extension of about 18 m to 22 m. By using a frame, it is considered to extend the construction span of the tunnel lining concrete in one cycle to shorten the construction period and accelerate the progress of the process for forming the tunnel lining concrete.

Japanese Patent Laid-Open No. 2001-280094 JP, 2003-262096, A JP, 2005-067949, A

By the way, for example, in the case of a commonly used tunnel lining formwork having a tunnel lining concrete construction span of about 10.5 m, the concrete is dried at the boundary portion of the tunnel lining concrete in continuous construction spans. By absorbing the cracks caused by shrinkage or temperature shrinkage, the occurrence of cracks in the construction span of each tunnel lining concrete can be effectively suppressed.

However, when the latter construction method (construction method using a long span tunnel lining form) is adopted, the construction span in one cycle of the tunnel lining concrete is, for example, from about 10.5 m to about 18 m to 22 m. Since it is extended, there is a problem that cracks are likely to occur due to drying shrinkage and temperature shrinkage in the middle part of the construction span of the long tunnel lining concrete of about 18 m to 22 m.

In order to solve the above problem, it is desirable to provide an induction joint for inducing cracks due to drying shrinkage or temperature shrinkage in the middle of the construction span of tunnel lining concrete with a construction span of 18 m to 22 m.

As a method of providing the above-mentioned induced joint in the middle part of the construction span of the tunnel lining concrete, after the cast concrete is hardened and the tunnel lining form is demolded, for example, a concrete cutter is used to harden it. A method of forming the induced joint by cutting the middle part of the construction span of the tunnel lining concrete into a groove shape is considered.

However, when the hardened tunnel lining concrete is cut into a groove with a concrete cutter by the above method, the concrete cutter is moved along the inner circumferential surface of the curved cross-sectional shape including the arch-shaped portion of the tunnel lining concrete. However, there is a problem in that much work and time are required because the tunnel lining concrete needs to be cut into grooves.

The present invention has been made in view of the above problems, and an object thereof is to provide a tunnel joint that can easily provide an induction joint at an intermediate portion of each construction span of tunnel lining concrete without requiring much labor and time. It is to provide an industrial formwork.

The present invention is a long span tunnel lining form having a construction extension of more than 10.5 m for forming a tunnel lining concrete for covering an inner wall surface of a tunnel in a mountain tunnel construction method. Upper frame for forming a lining space between the movable frame and the inner wall surface of the tunnel supported by the frame, and rotatably connected to the lower ends of both sides of the upper frame. And a frame main body configured to include a pair of side molds, wherein the gantry is integrally formed without being divided in the tunnel excavation direction, the mold main body is It is composed of a pair of split mold body main parts that are divided into two in the tunneling direction, and the pair of split mold main body parts have a slit-shaped gap of a constant width between the adjacent end faces all around. A state in which a plate member that is supported by the pedestal portion so as to be formed over the entire length of the lining space is supported in the gap, and a plate member for forming an induced joint is formed in the middle portion of each construction span. It is characterized in that it is inserted and arranged so that it can be pulled out.

Here, it is preferable that a press-fitting connection port to which a pressure-feeding pipe extending from a concrete pump is connected is provided at each of the rear end portions of the pair of split mold body portions of the mold body portion.

Also, the air vent pipe can be pulled out to the front part of the top end of the split formwork main body on the rear side in the tunneling direction of the formwork main body until it projects close to the top surface of the lining space. It is preferably attached to.

Further, each of the divided mold body portions of the mold body portion is provided with a plurality of expansion and contraction vibrators projecting forward and backward in the lining space at predetermined intervals in the tunnel advancing direction. preferable.

The surface of the plate member is preferably coated with a friction reducing material.

According to the present invention, the induced joint can be easily provided in the middle portion of each construction span of the tunnel lining concrete without much labor and time.

It is a front view of the tunnel lining formwork concerning the present invention. It is a side view of the tunnel lining formwork concerning the present invention. FIG. 3 is an enlarged detailed view of a portion A of FIG. 2. It is the BB sectional view taken on the line of FIG. It is CC sectional view taken on the line of FIG. It is a front view of a plate member. FIG. 7 is a side view of the plate member (a view in the direction of arrow D in FIG. 6 ). It is the EE sectional view taken on the line of FIG. (A)-(c) is a sectional front view which shows the tunnel lining work using the frame for tunnel lining concerning this invention in order of the process. (A)-(c) is a sectional side view which shows the tunnel lining work using the form for tunnel lining concerning this invention in the order of the process. (A)-(c) is a partial side sectional view which shows the method of placing the top surface part of the tunnel lining concrete in the tunnel lining work using the frame for tunnel lining according to the present invention in the order of the steps. It is a partial front view of the place where the induced joint of the tunnel lining concrete inner surface was formed. It is the FF sectional view taken on the line of FIG.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

[Tunnel lining formwork]
First, the structure of a tunnel lining formwork according to the present invention will be described below with reference to FIGS.

FIG. 1 is a front view of a tunnel lining formwork according to the present invention, FIG. 2 is a side view of the tunnel lining formwork, and FIG. 3 is an enlarged detailed view of part A of FIG.

The frame 1 for tunnel lining according to the present invention is for forming the tunnel lining concrete 4 that covers the inner wall surface of the tunnel T formed by excavating the ground in the mountain tunnel method. It is configured as a long-span slide center having a construction extension of more than 5 m (18 m in this embodiment). The inner wall surface of the tunnel T before being covered with the tunnel lining concrete 4 is provided with a primary lining 5 onto which concrete is sprayed. Further, in the following description, the extension direction of the tunnel T (the left-right direction in FIG. 2) is the “front-rear direction”, the width direction of the tunnel T is the “left-right direction”, and the wellhead side is the “front side” in the extension direction of the tunnel T. The face side may be referred to as the "rear side".

As shown in FIGS. 1 and 2, the tunnel lining frame 1 according to the present embodiment includes a gantry part 2 that is movable along the excavation direction X of the tunnel T (see FIG. 2), and the gantry part. 2 has a formwork main body 3 supported on it, and its entire length has a long span of 18 m. Therefore, as will be described later, the construction span L of the tunnel lining concrete 4 formed using the tunnel lining form 1 according to the present embodiment is 18 m, which is significantly longer than the conventional span of 10.5 m. Has been done.

Here, the gantry portion 2 is integrally formed without being divided in the excavation direction X of the tunnel T (left and right direction in FIG. 2), and includes the gate type truck 2A shown in FIG. This gate-type carriage 2A includes a base portion 2a and left and right support leg portions 2b that support the base portion 2a. At the lower end of each support leg portion 2b, the floor surface of the tunnel T is elongated. Traveling parts 7 such as rollers movable on a pair of left and right rails 6 laid in parallel along the direction (the left and right direction in FIG. 2) are attached. Therefore, the tunnel lining formwork 1 can move in the excavation direction X of the tunnel T (see FIG. 2) along the rail 6.

The formwork main body 3 is for forming a lining space S having a predetermined thickness with the inner wall surface of the tunnel T covered by the primary lining 5, and the digging direction X( It is composed of a pair of split mold body portions 3A and 3B that are split in two in the left-right direction of FIG. 2 (see FIG. 3).

Each of the divided mold body portions 3A and 3B has an arch shape as a whole along the inner wall surface shape of the tunnel T, and forms a lining space S above the arch shape portion of the tunnel T shown in FIG. An upper mold 3a for effecting a work, a pair of left and right side molds 3b for forming a lining space S on the lower side and both side wall portions of the arch-shaped portion of the tunnel T, and a pair of lower molds 3c. It is configured to include each. Here, the upper mold 3a is supported by a plurality of lifting jacks 8 provided on the base 2a of the portal dolly 2A so as to be vertically movable. Further, the pair of side molds 3b are rotatably connected to the left and right lower ends of the upper mold 3a, and the pair of lower molds 3c are connected to the lower ends of the respective side molds 3b. Each is rotatably connected. The left and right side molds 3b and the lower molds 3c are respectively connected to the other ends of the telescopic jacks 9 and 10 whose one end is connected to the gate type trolley 2A. Can be rotated with respect to the upper mold 3a and the side mold 3b.

Further, as shown in FIG. 1, a plurality of press-fitting connection ports 11a and 11b are formed in the upper mold 3a and the side mold 3b of the frame mold body 3 side by side in the front-rear direction (direction perpendicular to the plane of FIG. 1). Has been done. Here, the press-fitting connection ports 11a and 11b are used for the purpose of pouring or press-fitting the lining concrete 12 (see FIGS. 9 and 11) into the lining space S as described later. .. The press-fitting connection ports 11a and 11b can be installed not on the windows but on the frame-type main body 3 itself.

In the tunnel lining form 1 configured as described above, the form body 3 can be expanded or contracted inward by expanding and contracting the lifting jack 8 and the expansion and contraction jacks 9 and 10. The frame main body 3 is assembled along the inner wall surface of T to form a lining space S having a predetermined thickness with the inner wall surface of the tunnel T, and after the frame main body 3 is released from the mold. , The inside of the tunnel T can be moved in the excavation direction X (see FIG. 2).

By the way, in the divided mold body portions 3A and 3B which are divided into two parts of the frame body portion 3, a slit-shaped gap δ (see FIG. 3) having a constant width is formed over the entire circumference between the end faces adjacent to these. As shown in FIG. 3 and FIG. 5, the slit-shaped gap δ is provided in the middle portion of each construction span L (=18 m) to induce the joint 14 (see FIG. 12). And a plate member 15 for forming (see FIG. 13 ), the plate member 15 is arranged so as to be pulled out in a state of protruding over the entire circumference of the lining space S. The plate member 15 is preferably composed of a metal plate made of aluminum or steel.

Further, in the present embodiment, an expansion/contraction adjusting member (not shown) may be provided so as to straddle the divided frame main body portions 3A and 3B which are divided into two in the frame main body portion 3. As the expansion/contraction adjusting member, various known expansion/contraction adjusting members including a hydraulic cylinder, a feed screw mechanism and the like can be used. By providing the expansion and contraction adjusting member, for example, when the mold main body 3 is expanded or contracted inward, the divided mold main bodies 3A and 3B are bent, so that the slit-shaped gap δ becomes too wide. Even if it becomes too narrow or too narrow, it becomes possible to easily adjust the interval of the slit-shaped gap δ by the expansion and contraction adjusting member.

Here, the configuration and mounting structure of the plate member 15 will be described below with reference to FIGS.

4 is a sectional view taken along the line BB of FIG. 3, FIG. 5 is a sectional view taken along the line CC of FIG. 4, FIG. 6 is a front view of the plate member, and FIG. 7 is a side view of the plate member (FIG. FIG. 6 is a cross-sectional view taken along the line EE of FIG. 7.

As shown in FIG. 4, the plate member 15 is divided into a plurality of pieces along the circumferential direction, and the plurality of plate members 15 form an arch shape while maintaining a predetermined distance from the inner peripheral wall of the tunnel T. It is arranged. It should be noted that FIG. 4 shows only the plate member 15 for a half circumference.

As shown in FIG. 6, each plate member 15 is formed in a substantially rectangular flat plate shape, and its inner peripheral surface and outer peripheral surface are arc surfaces having a predetermined curvature. Then, both surfaces of the tip portion 15A (portion hatched in FIG. 6) protruding into the lining space S of each plate member 15 are tapered surfaces that are pointed toward the tip (upper end in FIGS. 6 and 7). These taper surfaces are coated with a friction reducing material (not shown) containing a super absorbent resin.

A boss 16 is provided on the left and right of one surface (front surface in FIG. 6) of a portion 15B (a portion other than the tip end portion 15A) facing the outside of the lining space S of each plate member 15. A circular hole-shaped pin insertion hole 16a is formed through each boss 16. A guide member 17 that is long in the vertical direction is provided on the outer side in the left-right direction from the boss 16 on the other surface (the surface on the back side in FIG. 6) of each plate member 15. Further, a bracket 18 is inserted and fixed at a right angle to the center of the lower end of each plate member 15 in the width direction, and rectangular openings 19 functioning as handles are formed on both sides of the bracket 18. Here, the bracket 18 is projected long from the other surface of the plate member 15 (the inner surface of FIG. 6), and a notch hole 18a is formed in this protruding portion as shown in FIG. There is.

By the way, as shown in FIG. 5, on the adjacent end faces of the split mold main body portions 3A and 3B which are divided into two parts of the frame mold main body portion 3, the gap portion d is formed between the both end surfaces along the entire circumference. The supported support members 20 and 21 are attached. Here, both the support members 20 and 21 are provided in the same number as the plate member 15, and are arranged in an arch shape like the plate member 15. In this embodiment, the slit-shaped gap δ is formed as a gap between the support members 20 and 21.

Here, as shown in FIG. 5, one (front) support member 20 is formed in a rectangular frame shape (channel shape), and is attached to a bracket 20a formed at a lower end portion of a portion facing the plate member 15. A bolt 22 and a nut 23 screwed to the bolt 22 are supported by a shaft 24 so as to be vertically rotatable. Further, a rectangular plate 25 that is long in the direction perpendicular to the paper surface of FIG. 5 is projectingly provided at a portion of the support member 20 facing the plate member 15, and two left and right portions of the plate 25 (the boss 16 of the plate member 15). The pin insertion hole 25a is provided at two places corresponding to the pin insertion hole 16a formed in the above. In addition, guide members (not shown) are provided at both left and right ends of the support member 20 (positions that engage with the left and right guide members 17 of the plate member 15). A protrusion 20b having a trapezoidal cross section whose width becomes narrower toward the tip is projected toward the lining space S at a position on the outer peripheral surface of the support member 20 that abuts on the plate member 15 (the left end portion in FIG. 5). It is set up. The protrusion 20b is formed long along the outer periphery of the support member 20 in the direction perpendicular to the paper surface of FIG.

The other (rear side) support member 21 is formed in an inverted L-shaped cross section, and the outer peripheral surface of the support member 21 is in contact with the plate member 15 (right end portion in FIG. 5). A protrusion 21a having a trapezoidal cross section whose width narrows toward the tip is provided so as to protrude toward the lining space S. The protrusion 21a is formed long along the outer periphery of the support member 15 in the direction perpendicular to the paper surface of FIG.

Then, each plate member 15 is attached to one (front side) support member 20 as follows. That is, as shown in FIG. 5, each plate member 15 is provided on the left and right guide members 17 and the support member 20 projecting on the plate member 15 in a state where the tip portion thereof projects into the lining space S. The two pin insertion holes 25a formed in the plate 25 of the support member 20 are engaged with the left and right guide members (not shown) and inserted into the slit-shaped gap δ between the support members 20 and 21. The pin 26 is positioned and supported by a pin 26 inserted into a pin insertion hole 16a formed in the two bosses 16 of the plate member 15. Then, from this state, the bolt 22 is passed through the notch hole 18a (see FIG. 8) formed in the bracket 18 of the plate member 15 as shown by the solid line in FIG. 5, and screwed into the end portion of the bolt 22. By tightening the nut 23, the plate member 15 is securely attached to the support member 20.

By the way, as shown in FIG. 3, a pressure feed pipe 31 extending from the concrete pump 30 is provided at the top end portion of each rear end portion of the divided mold body portions 3A and 3B divided into two parts in front of and behind the form body portion 3. Top press-fitting connection ports 27a, 27b to which (see FIG. 10) are connected are respectively provided. Further, an air bleeding pipe 28 covers the front side portion (the portion close to the plate member 15) of the top end portion of the divided mold body portion 3B on the rear side in the digging direction X of the tunnel T of the mold body portion 3. The work space S is attached so that it can be pulled out in a state of protruding until it comes close to the top surface portion of the work space S. As the air bleeding pipe 28, for example, what is known as "air bleeding metal fitting" manufactured by Daiei Koki Co., Ltd. is used.

Further, as shown in FIG. 3, in each of the divided mold body portions 3A and 3B of the mold body portion 3, a plurality of expansion and contraction vibrators 13 projecting in the lining space S so as to be able to move forward and backward are provided in the tunneling direction (Fig. 3 in the left-right direction) at appropriate intervals. As the expansion and contraction vibrator 13, for example, one known as "top end expansion and contraction vibrator" manufactured by Daiei Koki Co., Ltd. is used.

[Tunnel lining work]
Next, the tunnel lining work performed using the tunnel lining form 1 configured as described above will be described below with reference to FIGS. 9 to 13.

9A to 9C are front sectional views showing the tunnel lining work using the tunnel lining formwork according to the present invention in the order of steps, and FIGS. 10A to 10C are the same tunnel. 11A to 11C are side sectional views showing the lining work in the order of the steps, and FIGS. 11A to 11C are partial side sectional views showing the method of placing the top end of the tunnel lining concrete in the step of the lining work in the order of the steps. 12, FIG. 12 is a partial front view of a portion where an induction joint is formed on the inner surface of the tunnel lining concrete, and FIG. 13 is a sectional view taken along line FF of FIG.

For the tunnel lining work, in the mountain tunnel construction method, using the tunnel lining formwork 1 according to the present invention, the concrete 12 (see FIG. 9) is passed through the pressure feed pipes 31 extending from the two concrete pumps 30 shown in FIG. 10, respectively. And (FIG. 11) are simultaneously poured into the lining space S while being placed, whereby the tunnel lining concrete 4 covering the inner wall surface of the excavated tunnel T is constructed. The inner wall surface of the tunnel T is already covered with the primary lining 5 by spraying concrete.

More specifically, as shown in FIG. 10, the two concrete pumps 30 are arranged in front of and behind the tunnel T in the excavation direction X with the tunnel lining formwork 1 carried into the tunnel T interposed therebetween. The concrete 12 is introduced into the hopper of each concrete pump 30 from each concrete mixer truck 32. Here, the pressure feed pipes 31 extend from the two front and rear concrete pumps 30, respectively, and the concrete 12 injected into the hopper portion of each concrete pump 30 from each concrete mixer truck 32 has two lines of the respective pressure feed pipes 31. Are simultaneously pumped and supplied to the lining space S. As described above, by using the two-system concrete pump 30 and the pressure-feeding pipe 31, it is possible to effectively accelerate the progress of the process for forming the tunnel lining concrete 4. When two concrete pumps 30 are used, these two concrete pumps 30 are arranged side by side on one side (on one side) of the front or the rear of the tunnel lining formwork 1 in the tunneling direction X of the tunnel T. It is also possible to do so.

As shown in FIG. 10, the two systems of pumping pipes 31 extending from the two concrete pumps 30 are a main pipe 31a extending toward the inside of the tunnel lining formwork 1 and a main pipe 31a shown in FIG. It is configured to include left and right branch pipes 31b branched on both sides in the width direction of the tunnel T via a rotary valve 29 shown. Here, each branch pipe 31b is configured to include a plurality of pieces such as straight pipes and curved pipes having different lengths, and the plurality of selected pieces are assembled and connected to the press-fit connection ports 11a and 11b. By arranging such pieces and recombining these pieces, the branch pipe 31b can be removed from the lower press-fitting connection port 11a formed in the divided mold body portions 3A and 3B of the mold body portion 3. The upper press-fitting connection port 11b can be switched and connected, or the upper press-fitting connection port 11b can be switched to the top press-fitting connection ports 27a and 27b at the top end.

That is, as shown in FIGS. 9A and 10A, the left and right branch pipes 31b are connected to the lower press-fitting connection ports 11a, and the concrete 12 pumped from each concrete pump 30 is connected to the branch pipes 31b. The concrete 12 can be poured into the lower half portion of the lining space S (dot portion and hatching portion in FIG. 9A) by pouring or pressing into the lining space S at the same time.

Next, as shown in FIGS. 9(b) and 10(b), the left and right branch pipes 31b are connected to the upper-stage press-fitting connection port 11b, and the concrete 12 pumped from each concrete pump 30 is connected to each of them. By pouring or press-fitting the branch pipe 31b into the lining space S at the same time, the concrete 12 can be placed in the upper half of the lining space S (dot portion and hatching portion in FIG. 9B). ..

Finally, the left and right branch pipes 31b are connected to the top press-fitting connection ports 27a and 27b at the top end as shown in FIGS. 9(c) and 10(c), and are pumped from each concrete pump 30. By pouring or press-fitting the concrete 12 into the lining space S from the respective branch pipes 31b at the same time, the concrete 12 can be placed in the zenith portion (hatched portion in FIG. 9C) of the lining space S. it can. In this case, front and rear adjacent end portions of the divided mold body portions 3A and 3B that are divided into two in front and behind the form body portion 3 of the tunnel lining formwork 1 (the front-rear direction intermediate portion of the lining span L). The plate member 15 arranged in () functions as a baffle plate.

That is, for example, a top press-fitting connection port 27a at the top is provided at the rear end of each of the divided front and rear divided form body portions 3A and 3B of the form body portion 3 of the tunnel lining form 1. , 27b at the same time when the concrete 12 is poured into the zenith of the lining space S, the concrete 12 poured into the lining space S, as shown by the arrow in FIG. , 27b respectively toward the gable form 33 side. Then, as shown in FIG. 11B, the concrete 12 reaching the plate member 15 from the upstream side is washed up at the portion of the plate member 15 functioning as a baffle plate, and is pressed from each press-fitting connection port 27a, 27b. Each flows toward the frame 33. That is, after the concrete 12 flowing from the press-fitting connection ports 27a and 27b toward the end form 33 reaches the plate member 15 and the end form 33 by further press-fitting the concrete 12 into the lining space S, Since the flow toward the gable form 33 side is further prevented, the plate is driven upward along the plate member 15 and the gable form 33. Then, the concrete 12 poured into the lining space S from the one press-fitting connection port 27a flows over the plate member 15 and flows out to the existing tunnel lining concrete 4a side, and the existing tunnel lining concrete 4a side. While merging with the concrete 12, it reaches the top surface of the lining space S from the other portion on the side of the press-fitting connection port 27b, and is sequentially filled into the lining space S toward the gable form 33 side.

As described above, when the concrete 12 cast from the top press-fitting connection ports 27a and 27b reaches the top surface portion of the lining space S, the air remaining on the existing tunnel lining concrete 4a side of the plate member 15 is retained. However, since the escape area is lost, air is likely to be generated in the portion of the lining space S that is close to the top surface portion. However, in the present embodiment, since the air bleeding pipe 28 is provided so as to project close to the existing tunnel lining concrete 4a side of the plate member 15 and reach the portion near the top surface portion of the lining space S, there is no residue. The generated air can be released from the air bleeding pipe 28 into the inside of the tunnel lining formwork 1. As a result, no air is generated in the top surface portion of the lining space S near the plate member 15, and as shown in FIG. 11C, the top surface portion of the lining space S is filled with the concrete 12. can do. In addition, in this Embodiment, since the some expansion-contraction vibrator 13 was arrange|positioned at an appropriate space|interval in the extension direction of the tunnel T, the concrete 12 cast on the top surface part of the lining space S is compacted by the some expansion-contraction vibrator 13. It is possible to obtain a more solid and high-quality tunnel lining concrete 4.

By the series of lining work described above, the tunnel lining concrete 4 covering the inner wall surface of the tunnel T is constructed as shown in FIGS. 9(c) and 10(c). As the lining formwork 1, a long span one whose overall length is greatly increased from 10.5 m to 18 m is used, and two concrete pumps 30 are used to connect concrete from the two systems of pressure feed pipe 31. Since 12 are simultaneously placed in the lining space S, the construction span L of the tunnel lining concrete 4 performed in one cycle is significantly extended to 18 m, and the placing time of the concrete 12 can be greatly shortened. it can. Therefore, the progress of the process for forming the tunnel lining concrete 4, that is, the process from the placing of the concrete 12 to the curing and the demolding of the tunnel lining formwork 1 excavates the facet of the tunnel T. It becomes possible to follow the progress of the process.

By the way, when the construction span L in one cycle of the tunnel lining concrete 4 is extended from, for example, about 10.5 m to about 18 m as described above, the middle portion of the construction span L of the long tunnel lining concrete 4 of about 18 m. In addition, as described above, there is a problem that cracks easily occur due to drying shrinkage and temperature shrinkage.

Therefore, in the present embodiment, the gap δ formed between the front and rear end faces of the divided mold body portions 3A and 3B, which are divided into two parts before and after the form body portion 3 of the tunnel lining formwork 1. Since the plate member 15 is inserted and arranged so as to be able to be pulled out in a state of protruding over the entire circumference of the lining space S, the plate member 15 is fixed to the concrete 12 after the concrete 12 cast in the lining space S hardens. When pulled out, the induced joint 14 is formed over the entire circumference in the middle portion of the construction span L of the tunnel lining concrete 4, as shown in FIGS. 12 and 13. This induced joint 14 induces cracks due to drying shrinkage and temperature shrinkage of the tunnel lining concrete 4, and by forming this induced joint 14 in the middle portion of the construction span L of the tunnel lining concrete 4. Since the cracks concentrate on the induced joints 14, it is possible to effectively avoid or suppress the occurrence of the cracks on the parts other than the induced joints 14 of the tunnel lining concrete 4.

By the way, the plurality of plate members 15 are pulled out in the following manner. That is, the pin 26 inserted into the pin insertion hole 16a formed in the boss 16 of the plate member 15 and the pin insertion hole 25a formed in the plate 25 of the support member 20 shown in FIG. The nut 23 that attaches the member 15 to the support member 20 is loosened, and the bolt 22 is rotated about the shaft 24 by about 90° as shown by the chain line in FIG. Then, the bolt 22 comes off from the notch hole 18a (see FIG. 8) formed in the bracket 18 of the plate member 15 and the attachment of the plate member 15 to the support member 20 is released, so that the operator can The plate member 15 can be pulled out from the tunnel lining concrete 4 by holding the two opening portions 19 for the handle formed at the lower end portion of the tunnel by hand. Then, on the inner peripheral surface of the tunnel lining concrete 4 from which the plate member 15 has been pulled out, the induced joint 14 as shown in FIGS. 12 and 13 is formed over the entire circumference (only a part of FIG. 12 is shown. (Shown). In addition, the openings of the induction joint 14 are opened toward the inside (the front side in FIG. 12, the lower side in FIG. 13) by the protrusions 20b and 21a (see FIG. 5) projecting from the support members 20 and 21, respectively. The tapered groove 14a is formed.

By the way, in the present embodiment, both surfaces of the tip portion 15A (hatched portion in FIG. 6) projecting into the lining space S of each plate member 15 are tapered surfaces that point toward the tip, so that each plate The member 15 can be easily pulled out from the tunnel lining concrete 4. Further, in the present embodiment, since both surfaces of the tip end portion 15A of each plate member 15 are covered with the friction reducing material containing the superabsorbent resin, the friction resistance force when pulling out each plate member 15 from the tunnel lining concrete 4 is increased. Is kept small, and each plate member 15 can be pulled out from the tunnel lining concrete 4 more easily.

As described above, in the tunnel lining formwork 1 according to the present invention, the formwork body part 3 is divided into two parts, the divided formwork part parts 3A and 3B are divided into two parts. Rather than being supported in a stable state by the gantry unit 2 which is integrally configured, a slit-shaped gap δ having a constant width is formed over the entire circumference between the adjacent end faces of the pair of divided mold body units 3A and 3B. Therefore, it is possible to continuously and continuously form the same with high accuracy. Further, since the plate member 15 is preliminarily attached between the adjacent end faces of the pair of split mold body portions 3A and 3B by inserting the slit-shaped gap δ which is continuously formed with high precision, the lining work is performed. By pulling out the plate member 15 after the concrete 12 cast in the space S has hardened, it is possible to easily form the induced joint 14 in the middle portion of the construction span L of the tunnel lining concrete 4. Therefore, compared with the case of using a method of cutting hardened tunnel lining concrete into a groove shape with a concrete cutter, for example, the induced joint is formed accurately and easily without much labor and time. It will be possible.

The application of the present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Of course. For example, the friction reducing material that covers the surface of the plate member that can be pulled out does not necessarily have to be a friction reducing material that contains a highly water-absorbent resin, but other friction reducing materials that include a material that absorbs water and swells, as well as hardening. It is also possible to use various known friction reducing materials that allow the plate member 15 to be easily pulled out from the tunnel lining concrete after being subjected to, for example, the force of a person.

Further, in the above embodiment, the tunnel lining formwork 1 having a total length of 18 m was used. However, as the tunnel lining formwork, for example, the total length of about 18 to 22 m is 10.5 m. Other long-span tunnel lining formwork that has a construction extension beyond that may be used.

1 Tunnel formwork 2 Frame part 2A Gate type trolley 3 Formwork body parts 3A, 3B Split formwork body part 3a Upper formwork 3b Side formwork 3c Lower formwork 4 Tunnel lining concrete 5 Primary lining 7 Traveling parts 11a, 11b Press-fitting connection port 12 Concrete 13 Expansion/contraction vibrator 14 Induction joint 15 Plate member 20, 21 Support member 22 Bolt 23 Nut 26 Pins 27a, 27b Top press-fitting connection port 28 Air bleed pipe 30 Concrete pump 31 Pumping pipe L Construction span S Lining space T Tunnel X Tunnel excavation direction d Interval δ Slit-like gap

Claims (5)

A long span tunnel lining form having a construction extension of more than 10.5 m for forming a tunnel lining concrete for covering an inner wall surface of a tunnel in a mountain tunnel construction method,
A gantry that can move in the tunnel excavation direction,
An upper mold and a pair of side molds rotatably connected to lower ends of both sides of the upper mold for supporting a lining space between the cradle and an inner wall surface of the tunnel. And a formwork main body configured to include
The gantry portion is integrally formed without being divided in the tunnel advancing direction, and the formwork main body portion is composed of a pair of divided formwork main body portions that are divided in two in the tunnel advancing direction,
The pair of divided form body portions are supported by the gantry so that a slit-shaped gap having a constant width is formed over the entire circumference between these adjacent end faces, and each construction is provided in the gap. A tunnel lining formwork in which a plate member for forming an induction joint is formed in an intermediate portion of a span so as to be pulled out in a state of protruding over the entire circumference of the lining space. The tunnel lining mold according to claim 1, wherein a press-fitting connection port to which a pressure-feeding pipe extending from a concrete pump is connected is provided at each rear end of the pair of split mold body parts of the mold body part. frame. Attached to the front part of the top end of the split formwork body part on the rear side in the tunneling direction of the formwork body part so that the air vent pipe can be pulled out in a state of protruding until it comes close to the top face part of the lining space. Form for tunnel lining according to claim 1 or 2. A plurality of expansion and contraction vibrators which project in the lining space so as to be able to move forward and backward are respectively provided at predetermined intervals in the tunnel advancing direction in each of the divided frame main body portions of the frame main body portion. Form for tunnel lining according to any one of 3 above. The form for tunnel lining according to any one of claims 1 to 4, wherein a surface of the plate member is coated with a friction reducing material.

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