JP7241336B2 - Placement method of tunnel lining concrete - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Act ・Distribution of invitation letter for public demonstration experiment of full-scale construction experiment of high-speed lining concrete casting system (distributed by Okumura Gumi Co., Ltd. on August 28, 2018) ・High-speed lining concrete Full-scale construction experiment of casting system (September 25, 2018 to September 26, 2018 Construction Technology Research Institute) ・Nikkei Construction No. 696 (Published by Nikkei BP on September 24, 2018) ・Nikkan Kensetsu Kogyo Shimbun (September 26, 2018, published by Nikkan Kensetsu Kogyo Shimbun) ・Construction Newspaper (September 26, 2018, published by Nikkan Kensetsu Kogyo Shimbun) ・Nikkan Kensetsu Sangyo Shimbun (September, 2018) Published by Nikkan Kensetsu Sangyo Shimbun on the 27th of the month)

TECHNICAL FIELD The present invention relates to a method of placing tunnel lining concrete, and more particularly, to a method of placing tunnel lining concrete used for placing concrete in a lining space from a side wall portion of a tunnel to a crown portion of an arch-shaped portion. Regarding the setting method.

For example, in tunnel construction methods such as the mountain tunnel construction method, a construction method that uses a tunnel lining formwork called centr as a method for forming tunnel lining concrete that is constructed by covering the natural ground on the inner peripheral surface of an excavated tunnel. is generally employed (see, for example, Patent Documents 1 and 2). For example, as shown in FIG. 6, the tunnel lining formwork 50 is formed along the inner peripheral surface of a tunnel 53 having a shape including an arch-shaped portion 52 such as a horseshoe, extending from the side wall portion 55 to the upper portion of the tunnel 53. Plain concrete is preferably placed in the lining space 61 between the installed tunnel lining formwork 50 and the natural ground covered with the shotcrete 54 on the inner peripheral surface of the tunnel 53. By casting and hardening, the lining concrete is formed so as to be continuous with the concrete of the inverted portion 51 at the bottom of the tunnel.

Further, as the tunnel lining formwork 50, for example, in addition to the prefabricated tunnel lining formwork called a bara center, a mobile tunnel lining formwork called a slide center is known. As the excavation work progresses, the tunnel lining formwork 50 is re-installed every predetermined construction span of, for example, about 10.5 m, and the tunnel lining formwork is installed from the rear to the front in the excavation direction of the tunnel 53. Using the frame 50, the lining concrete for the side and upper parts of the tunnel 53 is placed in order to form it.

Then, in order to cast the lining concrete for the side and upper parts of the tunnel using the tunnel lining formwork 50, for example, as shown in FIGS. As a height area where concrete can be cast from the inspection window 56 provided in the formwork 50, for example, the area from the side wall portion 55 of the tunnel 53 to the shoulder portion of the arch-shaped portion 52 is inspected through the inspection window 56. A vibrator 58 is inserted through the inspection window 56, and the concrete 57 is placed while compacting the supplied concrete 57 (see FIGS. 7A to 7C). After that, as a height region where it is difficult to compact with the vibrator 58 while supplying the concrete 57 from the inspection window 56, the crown portion 59 (see FIG. 6) of the tunnel 53 Concrete 57 is press-fitted by a blow-up method from a blow-up input port 60 provided at the top end of the lining form 50, and the concrete 57 of the crown portion 59 is formed without compaction using a vibrator directly. A pattern is employed (see FIG. 7(d)).

More specifically, after installing the tunnel lining formwork 50 at a predetermined position, for example, from the lower part of the side wall part 55, concrete 57 is poured through the lower inspection window 56 and compacted using the vibrator 58. (See FIG. 7(a)), and a step of compacting using a vibrator 58 while pouring concrete 57 through an inspection window 56 in the middle toward the arch-shaped portion 52 at the top of the side wall portion 55 (FIG. 7 ( b)), and a step of compacting using a vibrator 58 while pouring concrete 57 up to the front of the crown 59 of the arch-shaped portion 52 through the upper inspection window 56 and, if necessary, the blow-up inlet 60. (See FIG. 7(c)), and press-in the concrete 57 from the existing lining concrete 62 side of the crown 59 through the blow-up injection port 60 by a blow-up method, and compact it directly using a vibrator. Instead, the lining concrete is poured by the step of filling concrete up to the end formwork 63 (see FIG. 7(d)).

JP 2001-280094 A Japanese Patent Application Laid-Open No. 2003-262096 JP 2015-67949 A

On the other hand, in the tunnel construction method in recent years, due to improvements in excavation technology, the progress of the process for forming the lining concrete, from concrete placement to curing and removal of the formwork for the tunnel lining, affects the face surface of the tunnel. It is no longer possible to keep up with the progress of the excavation process. For this reason, as a technique for accelerating the progress of the process of forming lining concrete, a plurality of concrete pumps are used (see, for example, Patent Document 3), or a tunnel lining having a construction extension of about 10.5 m, which is generally used, is used. Instead of the construction formwork, a long-span tunnel lining formwork preferably having a construction extension of about 18m to 22m is used to extend the construction span of the tunnel lining concrete performed in one cycle, thereby shortening the construction period. is being considered to be shortened.

In addition, when using a long-span tunnel lining form having a construction extension of preferably about 18 m to 22 m and extending the construction span of the tunnel lining concrete performed in one cycle, in the middle part of the construction span, Since cracks are likely to occur due to drying shrinkage and temperature shrinkage, especially when forming tunnel lining concrete with a long construction span, cracks due to drying shrinkage and temperature shrinkage are induced in the intermediate part. It is desirable to provide joints. For this reason, the applicant of the present application proposes a method of providing an induced joint in the middle part of the tunnel lining concrete, for example, in Japanese Patent Application No. 2018-147241, by making it protrude from the formwork surface of the tunnel lining formwork toward the lining space side. Discloses a method for forming an induced joint by arranging joint plate members in a row in the circumferential direction and attaching them so that they can be pulled out, and pulling out the joint plate members when the concrete placed in the lining space hardens. are doing.

However, if the joint plate members are arranged in series in the circumferential direction and attached by projecting from the formwork surface of the lining form to the lining space side, the protruding portion of the joint plate member does not enter the lining space. The flow of the poured concrete is impeded, and it becomes difficult to sufficiently fill the portion where the plate member protrudes with concrete, which may deteriorate the quality of the tunnel lining concrete.

In particular, when forming tunnel lining concrete using a long-span tunnel lining formwork, the present invention relates to joint plate members attached in a continuous manner in the circumferential direction in the middle part of the construction span. To provide a tunnel lining concrete casting method capable of obtaining high-quality tunnel lining concrete by facilitating filling of the lining space with concrete even in a portion protruding into the lining space. aim.

The present invention relates to a tunnel lining concrete construction method for forming lining concrete using a tunnel lining formwork, in which concrete is poured into the lining space from the side wall portion of the tunnel to the crown portion of the arch-shaped portion. A tunnel lining concrete casting method used when installing a tunnel lining, which protrudes from the formwork surface of the tunnel lining form into the lining space and forms a crack-inducing joint in the lining concrete after hardening. A joint plate member is provided extending in the circumferential direction of the lining space in the intermediate portion of the construction span between the existing lining concrete and the gable formwork, and extends from the side wall portion to the arch-shaped portion. The formwork for tunnel lining up to the crown is provided with openable and closable pipe connection ports that connect two pressure feed pipes extending from the concrete pump at two locations in the extension direction of the tunnel. From these two pipe connection ports, concrete is simultaneously pumped and supplied to the lining space to form the lining concrete . Lap-side pipe connection port provided in a portion adjacent to the formed existing lining concrete, and the joint plate member provided extending in the circumferential direction in the intermediate portion of the construction span, on the gable form side It consists of intermediate pipe connection ports arranged close to each other, and when concrete is simultaneously sent from the two pipe connection ports via two systems of pressure feed pipes to the lining space, the above-mentioned eyes The ground plate member guides the concrete that has been pressure-fed and supplied from the intermediate pipe connection port toward the end formwork side, and the concrete that has reached the joint plate member from the existing lining concrete side is guided to the joint plate member. To provide a tunnel lining concrete casting method for casting concrete in a lining space from a side wall part of a tunnel to a crown part of an arch-shaped part while guiding the concrete to be pushed up by a part of a joint plate member. Thus, the above object is achieved.

In the method for placing tunnel lining concrete of the present invention, the pipe connection ports provided at a plurality of locations at intervals in the extension direction of the tunnel are provided at intervals in the vertical direction in a plurality of stages. Preferably, in each stage from the lower stage to the upper stage, concrete is simultaneously pressure-fed and supplied from the plurality of pipe connection ports, and the lining concrete is placed upward in sequence.

Further, in the tunnel lining concrete casting method of the present invention, the joint plate member is placed from the formwork surface of the tunnel lining formwork to the lining space at a height of 10 to 70% of the thickness of the lining space. is preferably provided so as to protrude from the

Furthermore, in the tunnel lining concrete casting method of the present invention, the tunnel lining form is preferably a long-span tunnel lining form having a construction extension of 10.5 m or more.

According to the method of placing tunnel lining concrete of the present invention, when forming tunnel lining concrete using a long-span tunnel lining formwork in particular, the intermediate portion of the construction span is continuous in the circumferential direction. To obtain tunnel lining concrete of good quality by facilitating the filling of the lining space with concrete even at the part where the joint plate member installed and attached protrudes into the lining space.

(a) to (c) are schematic cross-sectional views for explaining a method of constructing tunnel lining concrete using a tunnel lining formwork. (a) to (c) are schematic vertical cross-sectional views for explaining a method of constructing tunnel lining concrete using a tunnel lining formwork. FIG. 5 is a schematic front view for explaining a state in which the joint plate members are continuously installed in the circumferential direction; (a) is a front view explaining a joint plate member, (b) is schematic sectional drawing of the state which attached the baffle plate member. 4(a) to 4(c) are schematic vertical cross-sectional views taken along line AA in FIG. 3, explaining a method of placing tunnel lining concrete according to a preferred embodiment of the present invention; FIG. 5 is a schematic cross-sectional view illustrating a state in which a tunnel lining formwork is installed along the inner peripheral surface of a tunnel in a conventional method for placing tunnel lining concrete. 1(a) to 1(d) are schematic side views, partly in cross-section, for explaining the work procedure of a conventional tunnel lining concrete placing method.

A tunnel lining concrete casting method according to a preferred embodiment of the present invention is shown in FIGS. 1(a) to 1(c) and FIGS. As described above, the lining concrete 20 constructed to cover the inner peripheral surface of the excavated tunnel 40 is preferably poured from two concrete pumps 30 at the same time using a tunnel lining formwork 10 called a center. Even when a joint plate member 25 for forming an induced joint that induces cracks is attached to the intermediate portion of the construction span when forming by placing while supplying, the arch-shaped portion from the side wall portion 40a of the tunnel 40 is attached. By filling the entire lining space 21 up to the crown portion 40c of 40b with the concrete 22 without gaps, the lining concrete 20 of good quality was adopted as a casting method. It is.

That is, in the recent tunnel construction method, due to improvements in excavation technology, the progress of the process for forming the lining concrete 20 from placing the concrete 22 to curing and demolding of the tunnel lining formwork 10 is 40 can no longer keep up with the progress of the process of excavating the face, and it is often not constructed efficiently. For example, a long-span tunnel lining formwork 10 having an extension of about 18 to 22m is used as a long-span tunnel lining formwork 10 preferably having a construction extension of 10.5 m or more instead of a formwork for construction. By using it, the construction span of the lining concrete 20 performed in one cycle is increased, and by using two concrete pumps 30 to simultaneously cast the concrete 22 from two systems of pressure-feeding pipes 31, the concrete 22 is By shortening the work time for placing, the progress of the process for forming the lining concrete 20 can be hastened.

In addition, in this embodiment, by using the long-span tunnel lining formwork 10 to increase the extension of the construction span of one cycle of the lining concrete 20, only the boundary portion between the adjacent construction spans will be covered with concrete. Cracks due to drying shrinkage and temperature shrinkage cannot be absorbed sufficiently, and cracks are likely to occur in the middle part of the construction span. A joint plate member 25 for forming is attached to the tunnel lining form 10 so as to protrude into the lining space 21 . When the joint plate member 25 is attached so as to protrude into the lining space 21 in the intermediate part of the construction span, the pressure feed pipe 31 of the two systems is connected to the lining space 21 via the two pipe connection ports 11a and 11b. The concrete 22 cast at the same time is inhibited from flowing in the portion where the joint plate member 25 protrudes, and it becomes difficult to sufficiently fill the concrete in the portion where the joint plate member 25 protrudes. By adopting the lining concrete part casting method, it is possible to easily fill the lining space with concrete even in the portion where the joint plate member 25 protrudes, and to obtain tunnel lining concrete of good quality. It's like

The tunnel lining concrete casting method of the present embodiment is a tunnel lining concrete construction method in which the tunnel lining concrete 20 is formed using the tunnel lining formwork 10, and an arch from the side wall portion 40a of the tunnel 40 is formed. A method of placing concrete used when placing concrete 22 in a lining space 21 up to a crown portion 40c of a shaped portion 40b, from a side wall portion 40a to a crown portion 40c of an arch shaped portion 40b. The tunnel lining formwork 10 is provided with openable and closable pipe connection ports 11a and 11b for connecting pressure feed pipes 31b extending from the concrete pump 30 at a plurality of locations (this embodiment Then, the concrete 22 is simultaneously pumped and supplied to the lining space 21 from these plural (two) pipe connection ports 11a and 11b to form the lining concrete 20. It's like The plurality of (two) pipe connection ports 11a and 11b are the lap side pipe connection port 11a provided in a portion adjacent to the previously formed existing lining concrete 20a, and the existing lining concrete 20a. It includes an intermediate pipe connection port 11b provided in an intermediate portion between the end frame 29 and protrudes from the formwork surface 10a of the tunnel lining formwork 10 into the lining space 21, and the post-hardening A joint plate member 25 for forming a crack-inducing joint in the lining concrete 20 extends in the circumferential direction of the lining space 21 and is adjacent to the existing lining concrete 20a side of the intermediate pipe connection port 11b. placed and provided. As shown in FIG. 5, when concrete 22 is simultaneously pumped and supplied from a plurality of (two) pipe connection ports 11a and 11b, the joint plate member 25 pushes the supplied concrete from the intermediate pipe connection port 11b. The tunnel is guided to flow toward the end formwork 29 side, and the concrete 22 reaching the joint plate member 25 from the existing lining concrete 20a side is guided to be pushed up at the joint plate member 25 part. Concrete 22 is placed in the lining space 21 from the side wall portion 40a of the arch-shaped portion 40b to the crown portion 40c of the arch-shaped portion 40b (see FIGS. 1(a) to 1(c)).

Further, in the present embodiment, as shown in FIGS. 1(a) to (c) and FIGS. 2(a) to (c), at a plurality of locations (two locations) at intervals in the extension direction X of the tunnel 40. The provided pipe connection ports 11a and 11b are provided in a plurality of stages (two stages in this embodiment) at intervals in the vertical direction, and in each stage from the lower stage to the upper stage, a plurality of locations (two locations ) from the pipe connection ports 11a and 11b, the lining concrete 20 is placed upward in sequence (see FIGS. 1(a) to 1(c)).

In this embodiment, the tunnel lining formwork 10 used in the tunnel lining concrete casting method is a slide center that can move in the extension direction (excavation direction) X of the tunnel 40, for example, about 18 to 22 m. It is a long-span center with an extension of The tunnel lining formwork 10 has substantially the same configuration as the tunnel lining formwork described in, for example, Japanese Patent Application Laid-Open No. 2015-67949, except that it is a long-span center.

That is, as shown in FIGS. 1(a) to 1(c), the tunnel lining formwork 10 is connected and integrated in the excavation direction X of the tunnel 40 (see FIGS. 2(a) to 2(c)). A plurality of gantry carriages 13 and arranged along the inner peripheral surface of a tunnel 40 supported by these integrated gantry carriages 13 and covered by a primary lining 23 of, for example, shotcrete, and a formwork main body 14 that forms the formwork surface 10 a inside the lining space 21 . The portal carriage 13 includes a base portion 13a and support leg portions 13b that support the base portion 13a. At the lower end of the support leg portion 13b, a running portion 13c that can run along the rails 24 laid on the floor of the tunnel 40 is provided. It can move in direction X.

The form body 14 is assembled so as to have a shape along the inner peripheral surface of the tunnel 40 covered with the primary lining 23, and is arranged at a predetermined distance from the inner peripheral surface of the tunnel 40. As a result, a lining space 21 having a predetermined thickness is formed. In addition, the formwork main body 14 forms an upper formwork 14a that forms a lining space 21 above the arch-shaped portion 40b of the tunnel 40, and a lining space 21 for the lower and both side wall portions 40a of the arch-shaped portion 40b. It includes a pair of side molds 14b and a pair of lower end molds 14c. The upper formwork 14a is supported by a plurality of lifting jacks 15a provided on the base portion 13a of the gate-type carriage 13 so as to be vertically movable. A pair of side molds 14b are rotatably connected to the lower ends of both sides of the upper mold 14a, and a pair of lower end molds 14c are rotatably connected to the lower ends of the respective side molds 14b. It is connected to the. One end of the side formwork 14b and the lower end formwork 14c are connected to the other ends of telescopic jacks 15b and 15c connected to the gate-type carriage 13. , the side molds 14b and the lower end molds 14c can be rotated with respect to the upper molds 14a and the side molds 14b.

As a result, the tunnel lining formwork 10 can expand and contract the formwork body 14 by extending and contracting the elevating jacks 15a and the telescopic jacks 15b and 15c. The formwork main body 14 can be assembled along the inner peripheral surface, and the formwork main body 14 can be moved in the excavation direction X inside the tunnel 40 after being demolded.

In this embodiment, the tunnel lining formwork 10 is a long-span formwork having an extension of, for example, about 18 to 22 m, thereby increasing the construction span and shortening the construction period. In addition, it preferably has a separable structure so as to be divided into two in the front-rear direction (tunnel excavation direction) X and the other. By configuring the tunnel lining form 10 to be separable into one side and the other, the movement and setting of the tunnel lining form 10 can be performed integrally with the long span, and the time for movement and setting can be shortened. While shortening, when constructing the lining concrete 20 of different cross-sectional parts such as the portal part of the tunnel 40 and the cross-sectional widening part, it is possible to assemble the formwork of these different cross-sectional parts and cure the poured concrete. For example, even if it is necessary to keep the tunnel lining formwork 10 in the same position for a longer period than usual without moving it, for example, one part is kept as it is and a different cross-section Separating the other part out of the part allows the operation of forming the lining concrete 20 to proceed by using the separated other part. This makes it possible to effectively avoid prolonging the process for forming the lining concrete 20 due to the influence of different cross-sections.

In the present embodiment, the lining space 21 formed by the tunnel lining formwork 10 and the inner peripheral surface of the tunnel 40 covered with the primary lining 23 has two systems as described above. Concrete 22 is supplied via a concrete pump (concrete pump car) 30 and pressure-feeding pipe 31 . That is, in this embodiment, as shown in FIGS. 2(a) to 2(c), the concrete pumps 30 are arranged forward and backward in the excavation direction X of the tunnel sandwiching the set tunnel lining formwork 10. Two concrete pumps 30 are arranged, and concrete 22 is thrown into the hopper portion of each concrete pump 30 from a concrete mixer truck 32 . Pressure-feeding pipes 31 are connected to the two front and rear concrete pumps 30, respectively. Concrete 22 can be simultaneously pressure-fed and supplied from two concrete pumps 30 to the lining space 21 via these two systems of pressure-feeding pipes 31 . By using two systems of the concrete pump 20 and the pumping pipe 31, it is possible to more effectively accelerate the progress of the process for forming the lining concrete 20. FIG. When two concrete pumps 30 are used, these two concrete pumps 30 should be arranged side by side on one side (one side) of the excavation direction X of the tunnel sandwiching the tunnel lining formwork 10. can also

Two systems of pumping pipes 31 connected to two concrete pumps 20 for pumping concrete are, for example, hard concrete pumping pipes made of cast iron, and each of them is connected to the concrete pump 30 at one end to be set. A main pipe 31a extending in the longitudinal direction (tunnel excavation direction) X of the tunnel lining form 10 to the inside of the tunnel lining form 10, and the main pipe 31a. It is formed to include branch pipes 31b that are branched from the ends on both sides in the width direction of the tunnel 40 via rotor valves 31c (see FIGS. 1(a) to 1(e)). The branch pipe 31b includes a plurality of piece pipes made up of straight pipes, curved pipes, etc., having different lengths. By rearranging these pieces, the branch pipe 31b can be switched from the lower pipe connection ports 11a and 11b to the upper pipe connection ports 11a and 11b, or can be connected to the upper pipe connection ports 11a and 11b. 11b can be switched to the zenith piping connection ports 12a and 12b for connection.

In this embodiment, as shown in FIGS. 1(a) and 1(b), coverings below the pipe connection ports 11a and 11b up to the pipe connection ports 11a and 11b to which the branch pipe 31b is connected are provided. After supplying the concrete 22 by pouring it into the work space 21 (see the dots in FIGS. 1(a) and 1(b)), the pipe is subsequently placed in the lining space 21 above the pipe connection ports 11a and 11b. Concrete 22 is supplied by press-fitting from the connection ports 11a and 11b (see hatched parts in FIGS. 1(a) and 1(b)). While switching the pipe connection ports 11a and 11b that connect the branch pipe 31b of the pumping pipe 31 to the pipe connection ports 11a and 11b of the tunnel 40, the concrete pouring and press-fitting process is repeated to form the crown of the arch-shaped portion 40b from the side wall portion 40a of the tunnel 40. Concrete 22 is placed in the lining space 21 up to the portion 40c.

That is, in this embodiment, the concrete pump 30 extends from the concrete pump 30 to the tunnel lining formwork 10 below the zenith from the side wall portion 40a of the tunnel 40 to the crown portion 40c of the arch-shaped portion 40b. The pipe connection ports 11a and 11b that can be opened and closed to which the branch pipe 31b of the pumping pipe 31 is connected are provided in a plurality of stages (two stages) at intervals in the vertical direction. , 11b, and supply concrete 22 by pouring concrete 22 from the pipe connection ports 11a, 11b into the lining space 21 below the pipe connection ports 11a, 11b. (See dots in FIG. 1(a)). When the concrete 22 poured from the lower pipe connection ports 11a and 11b reaches the height position of the pipe connection ports 11a and 11b, the concrete is continuously poured from the lower pipe connection ports 11a and 11b without switching the connection ports. By press-fitting 22, the concrete 22 is poured into the lining space 21 above the pipe connection ports 11a and 11b, preferably up to the height position of the intermediate portion between the upper pipe connection ports 11a and 11b. supply (see hatched area in FIG. 1(a)). As a result, the concrete pouring and press-fitting process is carried out at the lower piping connection ports 11a and 11b.

By the concrete pouring press-fitting process at the lower pipe connection ports 11a, 11b, the lower pipe connection is performed up to the height position of the intermediate portion between the lower pipe connection ports 11a, 11b and the upper pipe connection ports 11a, 11b. After the concrete 22 is press-fitted from the ports 11a and 11b, the connection ports for connecting the branch pipes 31b are switched from the lower pipe connection ports 11a and 11b to the upper pipe connection ports 11a and 11b, and the branch pipes 31b are connected to the upper pipe connection ports 11a and 11b. In the pipe connection ports 11a and 11b, the concrete pouring and press-fitting steps are repeated in the same manner. That is, from the branch pipe 31b of the pressure feed pipe 31 connected to the pipe connection ports 11a and 11b arranged in the upper stage, the pipe connection port 11a is provided in the lining space 21 below to the pipe connection ports 11a and 11b. , 11b to supply the concrete 22 (see dots in the upper part of FIG. 1(b)). When the concrete 22 poured from the upper pipe connection ports 11a and 11b reaches the height position of the pipe connection ports 11a and 11b, the concrete is continuously poured from the upper pipe connection ports 11a and 11b without switching the connection ports. By press-fitting the concrete 22, the concrete 22 is supplied to the lining space 21 up to the crown portion 40c of the arch-shaped portion 40b of the tunnel 40, which is the lining space 21 above the pipe connection ports 11a and 11b. (See the shaded area in the upper part of FIG. 1(b)). As a result, the concrete pouring and press-fitting process is carried out at the upper pipe connection ports 11a and 11b.

In this embodiment, the concrete pouring press-fitting process is performed at the upper pipe connection ports 11a and 11b which are the uppermost connection ports, and the lining space 21 up to the crown portion 40c of the arch-shaped portion 40b of the tunnel 40 is filled. After the concrete 22 is supplied, a zenith portion filling step is performed in which the concrete 22 is poured into the lining space 21 of the crown portion 40c of the arch-shaped portion 40b of the tunnel 40 (Fig. 1 ( c), see the shaded part). In the zenith portion filling step, the wrap side zenith pipe connection port 12a and the intermediate zenith pipe connection port 12a provided at the top end portion of the tunnel lining form 10 at intervals in the extension direction X of the tunnel 40 are connected. The branch pipes 31b of the two pressure feed pipes 31 connected to the two concrete pumps 30 are connected to the ports 12b (see FIGS. 2A to 2C), respectively, and these zenith pipe connection ports 12a, From 12b, this is done by simultaneously pressing and pouring concrete 22 .

In this embodiment, the lining space is formed between the inner peripheral surface of the tunnel 40 covered with the primary lining 23 and the formwork surface 10a of the formwork main body 14 of the tunnel lining formwork 10. 21, as shown in FIGS. 2(a) to 2(c) and 3, is provided to project from the formwork surface 10a into the lining space 21 to form crack-inducing joints in the lining concrete 20 after hardening. A joint plate member 25 extends in the circumferential direction of the lining space 21, and is arranged close to the existing lining concrete 20a side of the intermediate pipe connection port 11b. That is, in this embodiment, as the tunnel lining form 10, a long span having an extension of, for example, about 18 to 22 m is preferably used, and the long span tunnel lining form 10 is used. In this case, cracks due to drying shrinkage and temperature shrinkage of concrete cannot be sufficiently absorbed only at the boundary portions of adjacent construction spans, and cracks due to drying shrinkage and temperature shrinkage are likely to occur in the middle portion of the construction span. For this reason, in this embodiment, for the purpose of forming an inducing joint that induces cracking in the intermediate portion of the construction span, a plurality of joint plate members 25 are arranged in the tunnel lining formwork 10 for the purpose of forming the outer protruding embedded portion 25a. From the formwork surface 10a of the outer peripheral portion of the formwork main body 14, the outer lining space 21 side is protruded to the inside of the tunnel lining formwork 10, in the circumferential direction of the lining space 21. They are arranged in series.

Here, the joint plate member 25 is preferably a metal plate made of aluminum or steel and having a thickness of, for example, about 6 to 10 mm (about 9 mm in this embodiment). As shown, for example, the vertical width is about 300 to 600 mm and the horizontal width is about 400 to 700 mm (in this embodiment, the vertical width is about 500 mm and the horizontal width is about 700 mm), and the upper and lower sides are slightly curved. It is formed to have a substantially rectangular front shape. In addition, the joint plate member 25 is placed on both sides of the formwork surface 10a of the outer peripheral portion of the formwork main body 14 of the tunnel lining formwork 10, and is disposed so as to protrude toward the lining space 21 on the outer side. The inside of the inner substantially half portion that is arranged to project inward, sandwiching the outer protruding embedded portion 25a of the part and the formwork surface 10a of the outer peripheral portion of the formwork main body 14 of the tunnel lining formwork 10 and a protruding operating portion 25b. The outer protruding embedded portion 25a is preferably coated with a friction reducing material containing super absorbent resin.

As shown in FIG. 4(b), the outer protruding embedded portion 25a is inserted into the lining space through an insertion slit 26 provided in the form body 14 of the tunnel lining form 10 so as to extend in the circumferential direction. When the joint plate member 25 is inserted toward 21, it protrudes outward from the form surface 10a of the outer peripheral portion of the form body 14 of the tunnel lining form 10 with a protrusion height of, for example, about 250 mm. placed in In addition, the portion about 200 mm from the protruding tip of the outer protruding buried portion 25a is a tapered portion 25c in which the thickness is reduced from about 9 mm to about 2 mm toward the tip, thereby forming a lining concrete. The operation of pulling out the joint plate member 25 to the inside of the tunnel lining formwork 10 after the curing of the material 20 can be performed more smoothly.

Here, the height at which the outer protruding embedded portion 25a of the joint plate member 25 protrudes into the lining space 21 from the form surface 10a of the form body 14 of the tunnel lining form 10 is the height of the lining space 21. A height of 10 to 70% of the thickness is preferred. As a result, the concrete 22 is simultaneously pumped and supplied from the two pipe connection ports 11a and 11b of each stage by the above-described concrete pouring and press-fitting process, from the side wall portion 40a of the tunnel to the crown portion 40c of the arch-shaped portion 40b. When the concrete 22 is placed in the lining space 21, as will be described later, the concrete that has been pumped and supplied is placed in the middle by the outer protruding embedded portion 25a of the joint plate member 25 arranged so as to protrude into the lining space 21. It is possible to effectively guide the concrete 22 so that it flows from the inner pipe connection port 11b toward the end formwork 29 side, and the concrete 22 reaching the joint plate member 25 from the existing lining concrete 20a side is It is possible to effectively guide the joint member 25 so that it is pushed up by the part of the outer protruding buried portion 25a (see FIG. 5).

The inner projection operating portion 25b functions as a temporary fixing portion for fixing the joint plate member 25 to the tunnel lining formwork 10 until the concrete 22 placed in the lining space 21 hardens. , a portion that functions as a handle when pulling out the joint plate member 25 to the inside of the tunnel lining form 10 after the concrete 22 has hardened, and a portion that is close to the lower side is provided with a handle for the handle. A portion 25c is integrally provided so as to protrude on both sides.

The outer protruding embedded portion 25a of the joint plate member 25 is inserted toward the lining space 21 through the insertion slit 26 provided extending in the circumferential direction in the formwork surface 10a of the outer peripheral portion of the formwork main body 14. In this state, the back portion of the handle portion 25c is joined to the support steel material 14d fixed by welding or the like to the inner side of the formwork body 14 of the tunnel lining formwork 10, for example, by spot welding or the like that can be broken. The joint plate member 25 is temporarily joined to the supporting steel material 14d. As a result, each of the plurality of joint strip members 25 arranged continuously in the circumferential direction of the lining concrete 20 is placed in the tunnel lining formwork with the outer projecting embedded portion 25a protruding toward the lining space 21 side. 10, it becomes possible to temporarily fix in a stable state.

In addition, when the joint plate member 25 is pulled out to the inside of the tunnel lining formwork 10 after the concrete 22 placed in the lining space 21 has hardened, the handle portion 25c which is spot welded so as to be breakable. It is possible to pull out the joint plate member 25 by breaking the joint portion of the back portion of the joint plate member 25 and releasing the temporarily fixed state. The operation of pulling out the joint plate member 25 can be easily performed while preferably gripping the handle portion 25c provided on the inner projecting operation portion 25b.

According to the tunnel lining concrete casting method of the present embodiment, as described above, when the tunnel lining concrete 20 is preferably formed using the long-span tunnel lining formwork 10, Even in the intermediate portion of the construction span where the outer protruding embedded portion 25a of the joint plate member 25 attached in series in the circumferential direction protrudes into the lining space 21, the lining space 21 is easily filled with concrete. As a result, it becomes possible to obtain tunnel lining concrete 20 of good quality.

That is, according to the present embodiment, the openable and closable pipe connection port 11a for connecting the pumping pipe 31b to the tunnel lining formwork 10 from the side wall portion 40a to the crown portion 40c of the arch-shaped portion 40b, Lap-side pipe connection port 11a, existing lining concrete 20a, and gable formwork 11b provided at a portion adjacent to pre-formed existing lining concrete 20a in each stage arranged in two stages. 29, and is formed in two places of one intermediate pipe connection port 11b provided in the intermediate part between the tunnel lining form 10 and the outside from the formwork surface 10a of the tunnel lining formwork 10 to the lining space 21. The joint plate member 25 extends in the circumferential direction of the lining space 21 by protruding the protruding buried portion 25a, and is arranged close to the existing lining concrete 20a side of the intermediate pipe connection port 11b. It is

Thus, according to the tunnel lining concrete casting method of the present embodiment, concrete is poured into the lining space 21 from the side wall portion 40a to the crown portion 40c of the arch-shaped portion 40b. In the press-fitting step, when the concrete 22 is simultaneously pumped and supplied from the lap side pipe connection port 11a and the intermediate pipe connection port 11b of each stage, as shown in FIG. Immediately after being supplied to the lining space 21, the flow spreading toward the existing lining concrete 20a side is blocked by the outer protruding embedded portion 25a of the joint plate member 25, so that the joint plate member 25 is hit upward. As it rises, it is guided to flow toward the gable formwork 29 side. In addition, when the concrete 22 pumped from the intermediate pipe connection port 11b is supplied to the lining space 21 and then flows out to the inner peripheral surface of the tunnel 40 covered with the primary lining 23, the joint plate member 25 Therefore, the outer protruding buried portion 25 is extended through the space between the end of the outer protruding buried portion 25a and the inner peripheral surface of the tunnel 40 formed by the primary lining 23. It also flows out to the existing lining concrete 20a side.

On the other hand, the concrete 22 pressure-fed from the wrap-side pipe connection port 11a is prevented from spreading toward the existing lining concrete 20a immediately after being supplied to the lining space 21 by the existing lining concrete 20a. , it rises upward at the portion of the existing lining concrete 20a and is guided to flow toward the outside projecting embedded portion 25a of the joint plate member 25 arranged on the end formwork 29 side. Further, the concrete 22 guided to flow toward the outer protruding buried portion 25a reaches the portion of the outer protruding buried portion 25a protruding into the lining space, and reaches the portion of the tunnel lining form 10 on the side of the formwork surface 10a. Concrete 22 rises upward along the outer protruding buried portion 25a, and the concrete 22 on the primary lining 23 side flows out to the existing lining concrete 20a side from the outer protruding buried portion 25. The concrete 22 supplied from the connection port 11 easily merges as one in the lining space 21 on the side of the existing lining concrete 20a with respect to the outer projecting buried portion 25a.

As a result, according to this embodiment, even in the portion where the outer protruding embedded portion 25a of the joint plate member 25 attached in series in the circumferential direction in the intermediate portion of the construction span protrudes toward the lining space, Since the work space 21 is easily filled with concrete, a compaction device (not shown) such as a telescopic vibrator or formwork vibrator, which is attached to a predetermined portion of the tunnel lining form 10, is vibrated. By compacting the concrete filled in the lining space 21, it is possible to obtain the tunnel lining concrete 20 of good quality.

Therefore, according to the tunnel lining concrete casting method of the present embodiment, when the tunnel lining concrete 20 is formed using the long-span tunnel lining formwork 10, the intermediate portion of the construction span is Also in the part where the outer protruding buried part 25a of the joint plate member 25 attached in a continuous manner in the circumferential direction protrudes into the lining space, the lining space 21 is easily filled with concrete, and the quality is improved. It becomes possible to obtain tunnel lining concrete 20 .

It should be noted that the present invention is not limited to the above embodiments, and various modifications are possible. For example, the pipe connection port does not necessarily need to be provided in two stages below the zenith of the tunnel lining form from the side wall portion to the crown portion of the arch-shaped portion. It is also possible to provide three or more tiers and supply concrete to the lining space from each pipe connection port.

10 Tunnel lining formwork 10a Formwork surface 11a Lap side pipe connection port 11b Intermediate pipe connection port 12a Lap side zenith pipe connection port 12b Intermediate zenith pipe connection port 13 Portal carriage 14 Form body 20 Lining Concrete 20a Existing lining concrete 21 Lining space 22 Concrete 23 Primary lining 25 Joint plate member 25a Outer protruding buried portion 25b Inner protruding operating portion 29 End formwork 30 Concrete pump (concrete pump truck)
31 Pressure feed pipe 31a Main pipe 31b Branch pipe 40 Tunnel 40a Side wall portion 40b Arch-shaped portion 40c Top end (crown portion)
X Tunnel excavation direction

Claims (4)

In the tunnel lining concrete construction method that forms lining concrete using a tunnel lining formwork, when concrete is poured into the lining space from the side wall of the tunnel to the crown of the arch-shaped portion A method for placing tunnel lining concrete to be used,
A joint plate member that protrudes from the formwork surface of the tunnel lining formwork into the lining space and forms a crack-inducing joint in the lining concrete after hardening is placed between the existing lining concrete and the gable formwork. It is installed in the middle part of the construction span of , extending in the circumferential direction of the lining space,
Openable and closable pipe connection ports for connecting two pressure feed pipes extending from a concrete pump to the tunnel lining form from the side wall portion to the crown portion of the arch-shaped portion are arranged in the extension direction of the tunnel. are provided at two locations with an interval of , and from these two piping connection ports, concrete is simultaneously pressure-fed and supplied to the lining space to form the lining concrete,
The two pipe connection ports are a wrap-side pipe connection port provided in a portion adjacent to the previously formed existing lining concrete, and a circumferentially extending portion in an intermediate portion of the construction span. and an intermediate pipe connection port arranged close to the end formwork side of the joint plate member,
When the concrete that is respectively sent from the two pipe connection ports via two systems of pressure-feeding pipes is simultaneously pressure-fed and supplied to the lining space, the concrete that is pressure-fed and supplied by the joint plate member is transferred to the intermediate pipe. The tunnel is guided to flow from the connection port toward the end formwork side, and the concrete that has reached the joint plate member from the existing lining concrete side is guided to be pushed up at the joint plate member. A tunnel lining concrete casting method for casting concrete in the lining space from the side wall portion of the tunnel to the crown portion of the arch-shaped portion. The pipe connection ports provided at two locations with an interval in the extension direction of the tunnel are provided at a plurality of stages with an interval in the vertical direction, and at each stage from the lower stage to the upper stage, there are two locations. 2. The method of placing the tunnel lining concrete according to claim 1, wherein the concrete is simultaneously pumped and supplied from the pipe connection port, and the lining concrete is successively placed upward. The tunnel according to claim 1 or 2, wherein the joint plate member is provided so as to protrude from the formwork surface of the tunnel lining formwork into the lining space at a height of 10 to 70% of the thickness of the lining space. Method of placing lining concrete. The tunnel lining concrete casting method according to any one of claims 1 to 3, wherein the tunnel lining formwork is a long-span tunnel lining formwork having a construction extension of 10.5 m or more.

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