JP2018115554A - Construction method of floor slab - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a construction method for solving the problem in which transportation or installation accompanies enlarged installation scale and dangers and trouble in the inner construction of a tunnel with a large cross section because Pca floor slab is an integral structure in transverse direction and Pca intermediate wall is a rectangle and rigid structure.SOLUTION: A bearing is composed of side walls in left and right two lines adjacent a segment and an intermediate wall in more than 2 lines, a floor slab is composed of two pairs of Pca floor slabs facing each other in a transverse direction supported by two lines of the bearing of the side wall and the adjacent intermediate wall and a connection part connecting both pairs of Pca floor slabs between them, the intermediate wall is a continuous arch structure and is composed of a Pca intermediate wall in a shape parting a supporting part and an arch part vertically by a vertical end surface in installation and the connection part connecting both vertical surfaces each other, a floor slab construction crane is composed of an overhead crane clamping Pca floor slab installation points and mounting it to an upper frame on the supporting column installed on an upper saddle and a lower saddle.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a floor slab, a support, a middle wall, a joint formwork, and a floor slab erection crane used when installing a floor slab, which are installed on a road or railway tunnel with a large section.

  Conventionally, many floor slabs and supports installed in tunnels such as roads and railways with large cross sections are installed on the floor slabs of Pca concrete members integrated in the transverse direction (hereinafter referred to as “Pca floor slabs”) and the left and right wall surfaces. In general, it is composed of a bearing on the spot (hereinafter referred to as “RC side wall”) and a support for the inner wall of the Pca concrete member (hereinafter referred to as “Pca inner wall”).

  The reason why the left and right RC side walls can be constructed on the site rather than an expensive Pca concrete member is that the transportability of the segments is not impaired. On the other hand, the reason why the Pca floor slab and the Pca inner wall cannot be constructed on the spot is that the work of reinforcing bars and formwork support accompanying the construction impairs the transportability of the segments.

  In addition, the Pca floor slab is integrated in the transverse direction because the transport path of the segment is below the Pca floor slab, and the transport path of the Pca floor slab material needs to be on the Pca floor slab immediately after installation. It is. Because, if the structure of the Pca floor slab is not integrated in the transverse direction but individually between the single diameters, the joint connection is not completed immediately after the installation of the Pca floor slab and is unstable, and the transportability of the Pca floor slab is impaired. It is.

  FIG. 1 is a diagram showing a comparison between a Pca floor slab installation structure according to the prior art and a Pca floor slab installation structure according to the present invention. For example, as shown in FIG. 1A, Non-Patent Document 1 describes a structure that employs a Pca floor slab integrated with two spans and a central Pca middle wall in a road tunnel. Patent Document 1 describes a structure that employs a Pca floor slab integrated with three diameters and two rows of Pca middle walls, as shown in FIG. The Pca floor slab of the present invention shown in FIG. 1 (c) will be described later.

  Moreover, FIG. 2 is a figure which shows the comparison with the installation structure of the Pca intermediate wall which concerns on a prior art, and the installation structure of the Pca intermediate wall which concerns on this invention. FIG. 2A shows a structure in which conventional Pca middle walls having a rectangular and solid structure are connected in the longitudinal direction. The Pca inner wall of the present invention shown in FIG. 2 (b) will be described later.

JP 2006-200206 A

Concrete engineering Vol. 49 (2011) No. 49 12 p. 44 Figure 11 left Design and construction of tunnel segment and floor slab of Tokyo Metropolitan Expressway Central Shinagawa Line

In Non-Patent Document 1 and Patent Document 1, the Pca floor slab has a two-span structure in which the former is integrated in the transverse direction (FIG. 1 (a)) and a three-span structure in which the latter is integrated in the transverse direction (FIG. 1 (b). )), And the Pca inner wall has a rectangular and solid structure.
First, the reason why the floor slab is a Pca floor slab regardless of cheap on-site hitting, and further, the reason why the Pca floor slab is integrated in the transverse direction are as described above. If the tunnel has a large cross section, the integral structure will impair the transportability and installation of the Pca slab. Here, if the number of supports is increased, for example, the former two diameters are set to the latter three diameters, the floor slab thickness is reduced, and the structural rationality is ensured. However, it is still difficult to adjust the level and position of the support when the precast material is erected and when the number of supports increases. In a narrow pit, the transportability and erection are improved even if the number of supports is increased. It is difficult to do. In short, the required structure is not a multi-diameter structure in which the precast material is long and integrated in the transverse direction, but a multi-diameter structure in which short members having a single diameter are combined.

  On the other hand, the reason why the Pca inner wall has a rectangular and dense structure (FIG. 2 (a)) is because it is excellent in transportability and erection properties. In the case of making the cross section, the structural rationality of the Pca middle wall is impaired. Originally, column / girder structure, continuous arch structure, etc. reduce the overall quantity, but this is not possible because the transportability and erection of the Pca inner wall itself are not impaired, and the segments are transported during erection. This is because it cannot be said that the structure satisfies that the property is not impaired.

Moreover, the reason why the Pca floor slab and the Pca inner wall are not based on inexpensive on-site construction is as described above. When the tunnel has a large cross section, the space margin increases on the contrary. Despite the possibility of combined use, it has not been fully studied.
Furthermore, the floor slab erection crane has a structure that can be installed in a cantilever shape on the Pca floor slab so as not to impair the transportability of the lower segment. There is a problem that the limit comes out.

  The problems in the structure of the floor slabs and construction methods of roads and railway tunnels that have a larger cross section than those in the prior art have been described in detail above.

1) In the construction of large-scale floor slabs and inner walls, the actual situation is that there was no precast shape and structure and a method therefor that do not impair the transportability of the segments and also use inexpensive on-site strikes.
2) The Pca floor slab, which is used in combination with construction on the spot, is premised on reciprocating concrete transport on the same floor to the construction site, but there was no precast shape and structure to enable this, and a method for it. Is real.
3) For Pca floor slabs that are used in combination with on-site striking, the formwork for on-site striking can be removed, moved, and assembled continuously in the axial direction without hindering the transport of segments on the return path. As a premise, there was no formwork or precast shape that could achieve this.

4) Since the Pca floor slab is integrated in the transverse direction, it is a prerequisite for securing the transport of the segment below the Pca floor slab. It was difficult to improve sex.
5) Even if a method is adopted in which individual Pca floor slabs with a single diameter are joined and integrated in the transverse direction in order to improve transportability and erection properties, the same floor slab can be used up to the installation location of this floor slab. Actually, there was no precast shape and structure for transporting the Pca floor slab, and no method for that purpose.

6) Although the inner wall of Pca is originally a structure with a downward opening such as a pillar / girder structure or a continuous arch structure, the overall volume is reduced. However, the precast shape and structure that realize this in terms of transportability and erection properties Actually, there was no method for that.
7) The floor slab erection crane has an unstable structure in which it is installed in a cantilever shape over the installation location on the Pca floor slab, and the equipment structure cannot withstand the increase in weight.

To solve the above problem,
a The bearing is composed of two rows of left and right side walls in contact with the segment and two or more rows of middle walls standing upright from the invert concrete. Two slabs facing each other in the transverse direction that are supported by two rows of support on the side wall of one row and the middle wall of the next row are joined to each other by spotting between them. It consists of a joint part to be made.

b The Pca floor slab is provided with a thickened portion that widens downward in two rows of support locations on the side wall and the adjacent middle wall. A first through-hole penetrating the vicinity of the flat center of both thickened portions is provided, and a drop bar is passed through both first through-holes to temporarily fix the Pca floor slab. A support rubber plate is fixed to the Pca floor slab side on the lower surface of the Pca floor slab, and a joining reinforcing bar protrudes beyond the inner wall in the transverse direction.
In addition, the Pca floor slab is provided with a second through hole at an end portion on the joint portion side, and a suspension rod that suspends the joining formwork is passed through.
The installation of Pca floor slabs, in the installation of two sets of Pca floor slabs facing each other, at the time of erection, penetrating through the first through hole, penetrating the widened portion, respectively, in the drop hole provided in advance on the support side, Drop the dropping rod and temporarily fix it to the bearing side. A suspension rod is penetrated and fixed in the second through hole. A gauge plate is fixed to both suspension rods facing each other, and the design separation is maintained.
A rail clip can be fixed in advance on the upper surface of the gauge plate, and two rails for floor slab transportation carts are installed here.

If the c Pca inner wall is erected continuously in the invert, it forms a continuous arch structure including a support portion and an arch portion, and the continuous arch structure has an approximately semicircular arch-shaped opening below. The Pca inner wall has a shape in which the vertical end face when standing is vertically divided at least one of the support portion and the arch portion, and stands while being temporarily fixed to each other by both vertical surfaces of the adjacent Pca inner wall. Set up.
Further, the Pca middle wall has a U-shaped space serving as a connecting portion at the upper end of the arch portion, and after temporarily fixing the Pca middle wall while standing upright in the invert, the U shape of the adjacent Pca middle wall It is characterized in that both are integrated in the axial direction by filling the concrete space with connecting reinforcing bars that continuously connect the two in the shape space.

d The slab erection crane has two upper saddles that run on rails on the installed Pca slab, two lower saddles that run on rails on invert concrete, and upper pedestals on both sides that stand up from here. It consists of lower pedestals on both sides, an upper frame supported by each leg, and an overhead crane that runs on the upper frame. On the other hand, the lower saddle width is reduced, and an outrigger is arranged in the transverse direction from the upper frame to obtain a reaction force for preventing the fall from the segment.

e. The joint part formwork penetrates the second through-holes arranged in advance at the joint side end of the two pairs of Pca floor slabs facing each other, the upper surface of the Pca floor slab, It is characterized in that the concrete weight of the joint is held by the large pulling material via the dam plate and the butter material while being suspended by a suspension rod that is fixed to the nut here while penetrating the perforated plate at the lower end.
In addition, the demolding movement of the joint formwork is a large pulling in the demolding movement of the joint formwork of the concrete strength development span with the lifting formwork remodeling cart that runs on the two rows of rails on the invert concrete. When the telescopic strut connected to the material support is in the extended state, it receives the lower end of the large pulling material, and then shrinks it while releasing the joint formwork, and then removes and releases the formwork, below the uncured concrete span It is characterized by moving to the lower part of the joint between the facing Pca slabs of the non-constructed span.

According to the present invention, the support is composed of two rows of left and right side walls and two or more rows of inner walls, and the floor slab is supported by two sets of facing Pca supported on one row of side walls and one row of adjacent inner walls. Since it is comprised from a floor slab and the junction part between both, there exist the following effects.
A. The segment transport path for the outbound return path can be taken between the side wall directly under the Pca floor slab and the adjacent middle wall. Realizes the combination of inexpensive on-site construction and reduces construction costs.
(B) Since the joint that can be taken between the outer walls can be expanded freely, the design flexibility is high with respect to the large cross-section, and it is possible to use cheap on-site strikes as much as possible, and the structural rationality is also excellent.

(C) By adjusting the distance between the side wall and the adjacent middle wall, it is possible to suppress an increase in the weight of the two sets of Pca floor slabs facing each other, there is no unreasonable weight, and the construction work can be made safe and efficient.
D The Pca floor slab is supported by two rows of supports, so it is stable even if it is divided. Therefore, the Pca floor slab material and the truck mixer truck can be stably transported on this, and the segment transportation below the floor slab is not hindered.

(E) Since the Pca floor slab is supported by two rows of bearings, the vertical error of the Pca floor slab with respect to the bearings is easily absorbed. In addition, the joint portion can absorb the entire strain including the plane error of each support position, does not flutter, and improves fatigue durability.
The concrete transport to be placed at the joint part can be transported on the outbound route of the truck mixer truck on the two pairs of Pca slabs facing each other. No delay in shield digging process.

According to the present invention, the Pca floor slab is provided with a thickened portion that widens downward in two rows of support portions of the side wall and the adjacent middle wall, and a first through hole that penetrates the thickened portion is provided. The support rubber plate is fixed to the Pca floor slab side, and the joining reinforcing bar protrudes beyond the adjacent inner wall in the transverse direction. Therefore, the following effects can be achieved.
The Pca floor slab can be temporarily fixed immediately by dropping a drop bar into the first through hole of the thickened portion and a drop hole provided in advance on the support side in accordance with this. Thereby, without waiting for completion of a junction part, it can load-proof to operation of a floor slab erection crane and transportation of a Pca floor slab, it does not drop, and a construction cycle can be shortened.
Since the two support locations of the ku Pca floor slab are widened portions having a high rigidity and widened downward, the bearing load is dispersed and long-term durability can be secured. However, when there is no thickened part, although the rigidity is lowered, the concrete volume can be reduced, and the same effect can be obtained and the cost can be reduced.

The first through-hole can be pre-drilled in the support rubber plate joint, and the anchor bar can be inserted into the mortar after inserting the anchor bar after removing the drop bar according to the drop hole provided in the support. Therefore, since it can be diverted also to the anchor bar hole of the present construction, there is no waste in the temporary structure and the permanent construction structure and the cost can be reduced.
Since the Pca floor slab protrudes the reinforcing bars for joining each other, if the upper formwork of the reinforcing bar is installed here and placed in the concrete, both can be easily joined.

According to the present invention, since the Pca floor slab is provided with the second through hole that allows the suspension rod to pass through at the joint side end, the following effects can be achieved.
When installing the Pca floor slab, the gauge plate is passed through a suspension bar that penetrates the second through-hole facing each other and bolted to maintain the design separation between the two. Therefore, the two sets of Pca floor slabs facing each other can be accurately and efficiently installed at the design position.
A rail clip is previously fixed to the upper surface of the gauge plate, and two rows of floor slab carriage rails are installed here. As a result, the forward and backward conveyance paths of the truck mixer truck can be taken on the left and right Pca floor slabs, and the gauge of the rails for the floor slab transportation trucks can be ensured correctly, and derailment of the trucks can be prevented.

By installing rails for floor slab carriages, two pairs of Pca floor slabs facing each other can be fixed in a ladder shape with two rows of rails and gauge plates in the longitudinal direction. These positions do not shift during the travel of the floor slab carriage.

According to the present invention, when the Pca inner wall is continuously erected on the invert, a continuous arch structure including a support portion and an arch portion is formed, and the continuous arch structure has an approximately semicircular arch-shaped opening below. The vertical end surface at the time of standing is a shape that vertically divides at least one of the support portion and the arch portion, and the vertical end surface is erected while being temporarily fixed to each other on both vertical surfaces of the adjacent Pca inner wall. The effect of this can be achieved.
Since it is a continuous arch structure, it can be made into a stable structure with excellent compression, and it can increase durability and reduce costs by having a large opening.
The So Pca middle wall is compact and excellent in portability because the vertical end face at the time of standing vertically divides the support part and the arch part vertically.

According to the present invention, the Pca middle wall has a U-shaped space serving as a connecting portion at the upper end of the arch portion, and after temporarily fixing the Pca middle wall while standing upright in the invert, By filling the U-shaped space of the wall with the connecting rebars that connect both continuously in the upper concrete, the both are integrated in the axial direction, so the following effects can be achieved.
If bars are placed in a U-shaped space and filled with concrete, this connecting portion can easily connect adjacent Pca inner walls, and the installation and connection work becomes efficient.
H The Pca middle wall is light in the upper part where the U-shaped space is provided, and the support part is solid and heavy, so that it has good stability when erected, and the work is safe and efficient.

Tsu Since the concrete of the connecting part is filled in the U-shaped space, the side frame is unnecessary and the construction period can be shortened.
The concrete filled in the U-shaped space of the connecting part receives the floor slab load by the compressive force, converts it into a vertical axial force by the arch action and transmits it to the support part, so the base of the Pca inner wall is bent The moment is not generated and the structure is simplified for the pillar / girder structure that is not.
G. The continuous arch structure is not divided in the tunnel axis direction, but in the cross-sectional direction, because it is long, so there is little movement of the crane when erected, and construction efficiency is excellent.

According to the present invention, in the floor slab erection crane, the saddle has a stepped arrangement at the upper and lower stages, the lower legs on both sides are provided with a gradient toward the center from the upper side to the lower side, and the outriggers are arranged in the transverse direction from the upper frame. Therefore, the following effects can be obtained.
Since the saddle is arranged in steps on the upper stage on the Pca floor slab and on the lower stage on the invert concrete, when the Pca floor slab is installed, the cantilever-like overhang is not created, the structure is simplified, and the crane work is also stable and stable. It will be safe.

The lower pedestal is provided with a gradient that approaches the center from the top to the bottom and secures the segment transport space on both sides, so that it does not affect the transport performance of the segment that requires a reciprocating space and does not delay the shield digging process.
N Even if the lower leg is an unstable structure that sinks downward from above, an outrigger is placed in the transverse direction from the upper frame to obtain a reaction force for preventing the fall from falling, so the crane work is always stable and falls. There is nothing. In addition, a more reliable effect can be obtained if an operation-type outrigger is disposed in the segment conveyance space vertically below the lower leg (not shown).

According to the present invention, the joint formwork hangs the large pulling material with the suspension rod penetrating the second through hole of the Pca floor slab, and the concrete weight of the joint is determined via the dam plate and the butter material. Since it is held by the large pulling material, the following effects can be obtained.
Since the hanging rod is not buried, it can be diverted and construction costs can be reduced.
The joint form can be suspended by a suspension rod that penetrates the second through-hole and does not need to be received by the form support, so there is a space below, and axial installation, removal and movement Is easily realized and efficient.

  According to the present invention, the joint formwork can be installed and removed by the telescopic formwork replacement cart that runs on the two rows of rails on the invert concrete. When moving the mold, the telescopic strut connected to the large pulling material holder receives the lower end of the large pulling material in the extended state, and after that, it is in a contracted state while releasing the joint formwork, and then the mold is removed and demolded. And while moving under the formwork of a concrete unhardened span, it moves to the lower part of the joint part between the facing Pca floor slabs in the unconstructed section, and therefore, the following effects can be obtained.

ヒ With the telescopic formwork refilling carriage, the formwork is removed and removed, and moved under the formwork at the joint part of the uncured concrete span and moved to the unconstructed section, so it is continuous in the axial direction. Efficient on-site strike construction.
The telescopic formwork replacement cart is rail-driven, and its position is automatically determined, ensuring efficiency and accuracy.

FIG. 1 is a diagram showing a comparison between a Pca floor slab installation structure according to the prior art and a Pca floor slab installation structure according to the present invention. FIG. 2 is a diagram showing a comparison between the Pca middle wall installation structure according to the prior art and the Pca middle wall installation structure according to the present invention. FIG. 3 is a diagram showing the structure of the Pca floor slab according to the first embodiment in three views. FIG. 4 is a plan view and a front view in which the Pca floor slab of Example 1 is arranged in a three-span structure in the transverse direction. FIG. 5 is a diagram showing details of joining of the Pca floor slab and the Pca middle wall. FIG. 6 is a diagram illustrating an example when the Pca floor slab and the Pca middle wall are finally fixed. FIG. 7 is a view showing details when a gauge plate is installed and a floor slab carriage rail is laid using the gauge plate. FIG. 8 is a plan view and a side view in which the Pca floor slab of Example 1 is arranged in a three-span structure in the transverse direction. FIG. 9 is a diagram showing a three-view diagram and an arch structure representing the structure and shape of the Pca middle wall according to the present invention. FIG. 10 is a diagram showing another structure and shape of the Pca middle wall according to the present invention. FIG. 11 is a diagram illustrating one cycle of a process of sequentially installing the Pca inner wall of the second embodiment in the longitudinal direction in the tunnel and constructing the connection portion. FIG. 12 is a diagram illustrating one cycle of the process of installing the Pca floor slab of Example 1. FIG. 13 is a diagram showing one cycle of a process for constructing a joint portion between Pca floor slabs in the transverse direction. FIG. 14 is a diagram showing details of step 2 in FIG. FIG. 15 is a diagram showing details of step 3 in FIG. FIG. 16 is an enlarged view showing the joint form in the transverse direction when the telescopic strut is extended. FIG. 17 is an enlarged view of the cross-sectional shape in the longitudinal direction of the joint form at the second through-hole portion. FIG. 18 is a three-sided view of a floor slab erection crane used when laying a Pca floor slab. FIG. 19 is a diagram illustrating a procedure for laying a Pca floor slab using a floor slab erection crane.

  As modes for carrying out the present invention, embodiments according to the present invention will be described below with reference to the drawings.

As Example 1 of the present invention, a structure of a Pca floor slab and a state in which it is installed in a tunnel will be described.
As shown in FIG.1 (c), when the installation structure by the Pca floor slab which concerns on this invention is two diameters, it connects Pca floor slabs between Pca inner walls with a junction part, and is between three diameters. In this case, the Pca floor slabs are joined to each other at the joint portion placed on the Pca middle wall located inside.

FIG. 3 is a diagram showing the structure of the Pca floor slab according to the first embodiment in three views. FIG. 3 (a) shows the bar arrangement status of the joint bars, and FIG. 3 (b) shows the arrangement status of the first through holes 15 and the second through holes 16. FIG.
As shown in the plan view, the Pca floor slab 1 shown in (a) has a rectangular planar shape, and has a lap joint 12 in the transverse direction and a loop joint 11 in the longitudinal direction. Further, as shown in the front view, a thickened portion 14 that widens is provided in the vicinity of one end and the other end, and a support rubber plate 13 is attached to the lower surface thereof (see also the side view).
As shown in (b), in the Pca floor slab 2, as shown in the plan view, the first through hole 15 for the dropping bar is arranged in the thickened portion 14, and the second through hole 16 for the hanging bar is provided. It is arranged at the joint side end.

  FIG. 4 is a plan view and a front view (transverse direction) in which the Pca floor slab 2 of Example 1 is arranged in a three-span structure in the transverse direction. In the joint portion of the two Pca floor slabs 2 arranged in the transverse direction, the longitudinal line position is joined at the lap joint 12 and the transverse line position is joined at the loop joint 11.

In the front view shown in the lower part of FIG. 4, in “III cross section”, a first through hole 15 for a drop bar provided in the Pca floor slab 2 and a drop hole 19 provided in each of the RC side wall and the Pca middle wall 3 are provided. Then, the Pca floor slab 2 is fixed by installing the dropping bar 20. A detailed view of the joining of the Pca floor slab 2 and the Pca middle wall 3 is shown in FIG. A spacer 22 is provided on the surface of the drop hole 19 provided in the Pca inner wall 3. In FIG. 5, the Pca floor slab 2 is placed on the Pca middle wall 3, and the dropping rod 20 is penetrated through the through hole 15 of the Pca floor slab 2 and the dropping hole 19 of the Pca middle wall 3. .
Further, in the “IV cross section” of FIG. 7, the gauge plate 17 is installed and fixed by the hanging rod 21 using the through hole 16 for the hanging rod provided in the Pca floor slab 2, and the longitudinal direction is placed on the gauge plate 17. In this case, the floor slab carriage rail 18 is laid.

  FIG. 5 is a detailed view of the joining of the Pca floor slab 2 and the Pca middle wall 3. The Pca floor slab 2 is placed on the Pca middle wall 3, and the dropping bar 20 is dropped into the dropping bar of the Pca floor slab 2. The process of making it penetrate through the through-hole 15 for use and the drop hole 19 of the Pca inner wall 3 is shown. A spacer 22 is provided on the surface of the drop hole 19 provided in the Pca inner wall 3.

  FIG. 6 is a diagram illustrating an example when the Pca floor slab 2 and the Pca middle wall 3 are finally fixed. The dropped bar 20 that has been dropped is extracted, and instead, an anchor bar with a vinyl chloride cap is inserted through the through hole 15 for the dropped bar of the Pca floor slab 2 and the dropped hole 19 of the Pca inner wall 3. Thereafter, the through hole 15 for the dropping bar of the Pca floor slab 2 and the dropping hole 19 of the Pca inner wall 3 are filled with mortar and fixed.

  FIG. 7 is a detailed view when the gauge plate 17 is installed and the slab transport carriage rail 18 is laid using the gauge plate 17. As described above, by passing the suspension bar 21 through the through hole 16 for the suspension bar of the Pca floor slab 2 through the gauge plate 17, the gauge plate 17 is installed in the transverse direction so as to pass the Pca floor slabs 2 to each other. Thereafter, a floor slab carriage rail 18 is laid on the gauge plate 17 installed in the transverse direction over the longitudinal direction. At the same time, at the joint between the Pca floor slabs 2, cross bars 23 are installed at the lap joint 12 to be overlapped at the longitudinal line position, and internal bars are installed at the loop joint 11 at the cross line position. Strengthen the bond between the plates 2.

8 is a plan view (same as the upper view of FIG. 4) and a side view (longitudinal direction) in which the Pca floor slab 2 of Example 1 is arranged in a three-span structure in the transverse direction.
In the side view shown in the lower part of FIG. 8, in “I longitudinal view”, a drop bar 20 is installed through a drop hole 15 provided on the Pca floor slab 2 and a drop hole 19 on the Pca inner wall 3. Both of them are joined, and then the dropping bar 20 is extracted, and the anchor bar is inserted and the mortar is filled.
Further, in “II longitudinal section”, the suspension bar 21 penetrates through the through hole 16 for the suspension bar provided in the Pca floor slab 2 and the floor slab carriage truck 18 is laid on the Pca floor slab 2. Show.

(2) Pca middle wall As Example 2 of this invention, about the Pca middle wall, the structure and the state which installed it in the tunnel are demonstrated.
As shown in FIG. 2B, the Pca middle wall according to the present invention is not a rectangular shape as in the prior art, but is formed by connecting two adjacent Pca middle walls to form an arch structure. For this purpose, a U-shaped space serving as a connection portion is provided at the upper end of the arch portion, and two adjacent Pca inner walls are connected to each other.

FIG. 9 is a three-sided view showing the structure and shape of the Pca middle wall 3 according to the present invention in the upper figure, and is formed by combining one set obtained by joining two neighboring Pca middle walls with another adjacent set in the lower figure. The arch structure is shown.
As shown in the upper diagram of FIG. 9, the inner side of the Pca middle wall 3 forms a U-shaped structure (C and F) that matches the outer shape from the arch portion of A to the support portion of B, and anchors at the bottom Four are provided (D and E). Here, as shown in the figure, C and F, D and E are formed in a nested manner, so that once they are combined, they do not come out. In addition, construction efficiency can be improved by standing up and fixing while being temporarily fixed to each other with separate bolts when combined (not shown).
As shown in the lower figure of FIG. 9, the U-shaped space of the set of Pca middle walls 3 joined in the upper figure is filled with the connecting rebars that connect both of them continuously on the reinforcing bar. They are integrated in the axial direction (this point will be described later).
As described above, in FIGS. 2B and 9, the shape of the Pca middle wall 3 divided vertically by the arch part and the support part is regarded as one part, and two parts are combined into one set. It is not limited to the shape. That is, as shown in FIG. 10 (a), a shape with one part from the vertically divided arch part to the next vertically divided arch part through the support part, or as shown in FIG. 10 (b). It is good also as a shape which makes one part from the support part divided | segmented vertically to the support part divided | segmented perpendicularly through the arch part. 10 (a) and 10 (b), the support portion is not made to extend to the invert concrete, but an anchor is extended here leaving a certain distance from the invert concrete. At the time of installation, the root winding portion is provided between the support portion and the invert concrete by reinforcing bar placement and concrete placement.

FIG. 11 is a diagram illustrating one cycle of a process of sequentially installing the Pca middle wall 3 of the second embodiment in the longitudinal direction in the tunnel and constructing the connection portion.
In Step 1, the spacers are sequentially installed on the ground contact surface in the tunnel provided with the anchor holes for installing the Pca middle wall in the shield excavation direction.

  In step 2, the Pca middle wall is installed in order toward the shield tunneling direction using a middle wall installation crane and temporarily fixed. After temporary fixing, the anchored spacer is filled with mortar and fixed.

  In step 3, the connecting portion provided at the upper portion of the Pca middle wall is arranged by connecting reinforcing bars or unit reinforcing bars.

In step 4, concrete placement is performed on the connecting portion of the Pca middle wall using an agitator car after the bar arrangement in step 3 is completed.
Then, the above-described one cycle is repeated for each fixed construction section (one span), and the Pca inner wall is installed and fixed sequentially in the shield excavation direction.

FIG. 12 is a diagram showing one cycle of the process of installing the Pca floor slab of Example 1 following the process of fixing the Pca middle wall shown in FIG. 11.
In Step 1, spacers are sequentially installed at the correct level positions so that the Pca floor slabs can be installed at the designed level positions on the RC side wall and the Pca middle wall provided with pit holes in the shield excavation direction. In parallel, the Pca floor slab is lifted from the floor slab carriage using a floor slab erection crane and moved forward in the longitudinal direction (arrow direction).

  In step 2, the Pca floor slab transported using the floor slab erection crane is installed at a predetermined position (alignment of the Pca floor slab, unloading, see arrow). Subsequently, a dropping bar is installed through a through hole for a dropping bar provided in the Pca floor slab.

  In Step 3, a suspension bar is installed through a through hole for a suspension bar provided in the Pca floor slab, a gauge plate is installed at that time, and then a floor slab carriage truck is laid.

In step 4, the floor slab erection crane is moved, and the Pca floor slab installed in the next section is transported using the floor slab carriage truck laid in step 3.
Then, the above-mentioned one cycle is repeated for each fixed construction section (one span), and the Pca floor slab is installed and fixed sequentially in the shield excavation direction.

FIG. 13 is a diagram showing one cycle of a process for constructing a joint portion between Pca floor slabs in the transverse direction.
In Step 1, a reinforcing bar is assembled in order to construct a joint for connecting both sides to Pca floor slabs on both sides between three diameters that are installed and fixed for each construction section (one span).

  In step 2, the joint form used for construction of the joint in the previous construction section (span) is demolded, and the stretchable formwork is replaced in the next construction section (span) in which the reinforcing bars are assembled in step 1. Move using a trolley. The details are shown in FIG. In FIG. 14 (a), the joint mold used in the construction section (span) that has been constructed is lowered by shrinking (jacking down) the telescopic struts of the telescopic formwork replacement cart, and the joint mold The state where the hanging rod is removed from the frame is shown. The suspension rod holds and fixes the joint formwork on the bottom surface of the large pulling material with a perforated plate that is fixed to the nut, so after extending the telescopic strut and receiving the large pulling material, remove the nut and remove this nut. If the hole plate is removed, the suspension rod can be removed. Thereafter, the joint form can be removed and removed by shrinking the telescopic struts. FIG. 14 (b) shows a state in which the joint form has been detached and removed and placed on the telescopic formwork replacement carriage. And as shown to (c) of FIG. 14, while making the expansion-contraction type | mold form replacement carriage which mounted the joint part formwork run under the formwork of a concrete unhardened span, to the next construction area (span) Move.

In step 3, a joint part formwork is installed. It is installed by raising the joint formwork by extending the telescopic struts of the telescopic formwork replacement cart and connecting the suspension rod. As a detail thereof, FIG. 15A shows a state in which the telescopic formwork replacement cart moved below one construction section (one span) raises the joint formwork by the telescopic struts. FIG. 15 (b) shows a state in which the raised joint form is fixed to the joint by a hanging rod.
FIG. 16 shows an enlarged view of the joint mold in the transverse direction when the telescopic struts are extended, and FIG. 17 shows a cross-sectional shape in the longitudinal direction of the joint mold at the portion of the second through hole. Enlarged view.
Here, the large pulling material has a structure in which two girder members having a gap therebetween are back-to-back in the vertical direction. The weir plate is fixed to the upper part of the large pulling material via a joist. In addition, the suspension bar is previously installed in the second through hole of the Pca floor slab, and when the joint form is raised here, the suspension bar penetrates the gap of the large pulling material, and then the large pulling material The joint formwork is held and fixed to the suspension rod by a nut through a perforated plate provided on the lower surface of the plate.

In step 4, concrete is placed on the joint in the construction section (span) where the joint form is installed.
And the above-mentioned 1 cycle is repeated for every construction section (1 span), and a junction is constructed. Here, on the opposite Pca floor slab, it is possible to secure the transport path of the truck mixer truck on the forward return path, and on the lower side, the transport path of the segment on the forward return path.

(3) Floor slab erection crane As Example 3 of this invention, the structure of the floor slab erection crane used for installation of a Pca floor slab and the procedure for erection of the Pca floor slab will be described.
FIG. 18 is a three-sided view of a floor slab erection crane used when laying a Pca floor slab. 18A is a plan view of a floor slab erection crane, FIG. 18B is a side view (a view seen from the transverse direction), and FIG. 18C is a front view from the A cross section of FIG. It is a front view on the left side of the figure, and the right figure is a front view on the front side (left side of the figure) from the B cross section of (b). In the A cross section, the lower leg is Y-shaped from the upper frame, is inclined so as to approach the center from the upper side to the lower side, extends downward, and is joined to the lower saddle provided with the wheels. In the section B, the four upper legs extend vertically downward from the upper frame and are joined to the upper saddle provided with wheels, and the lower saddle width is reduced with respect to the upper saddle width. A crane saddle is placed on the upper frame, and moves on the upper frame in the longitudinal direction. Moreover, a trolley is mounted on the crane saddle via the crane girder and moves in the transverse direction on the crane girder.

  As a procedure for transporting the Pca floor slab, the Pca floor slab is moved by the floor slab transport cart (shown at the right end of FIG. 18B) that moves on the floor slab transport rail. Transport to. Therefore, the Pca floor slab is lifted using a crane included in the floor slab erection crane, and the crane is moved to a predetermined position in the longitudinal direction and in the transverse direction.

  Next, the installation procedure of the Pca floor slab using the floor slab erection crane will be described with reference to FIG. FIG. 19A is a plan view showing the relative positional relationship between the Pca floor slab and the floor slab erection crane that are sequentially installed, and FIG. 19B is the relative positional relationship between the installed Pca middle wall and the floor slab erection crane. (C) is a front view of the front side (left side of the figure) from the X cross section of (b), and the right figure is Y of (b). It is a front view of the back side (right side of a figure) from a section.

  A floor slab erection crane that moves using the upper and lower rails is equipped with a Pca slab that is transported by the slab trolley to the position of the upper pedestal of the floor slab erection crane. Lifting (upward arrow of Y section shown in FIG. 19C), the crane moves forward in the longitudinal direction to a predetermined installation position of the Pca floor slab (FIG. 19B). Next, the crane included in the slab erection crane moves in the crossing direction (the left-pointing arrow of the X section shown in FIG. 19 (c)), and the direction of the Pca slab is aligned and lowered at a predetermined installation position ((( c) an arrow indicating the rotation of the X section and a downward arrow).

1, 2 ... Pca floor slab, 3 ... Pca inner wall, 11 ... loop joint, 12 ... lap joint,
13 ... Bearing rubber, 14 ... Thickened part, 15 ... Through hole for dropping rod, 16 ... Through hole for hanging rod,
17 ... Gauge plate, 18 ... Floor slab carriage rail, 19 ... Drop hole, 20 ... Drop rod,
21 ... hanging rod, 22 ... spacer, 23 ... crossing bar

Claims (3)

A method of installing a floor slab for a support installed in a tunnel,
The bearing is installed from two rows of side walls in contact with the segment and two or more rows of middle walls erected from invert concrete between the side walls,
The floor slab is composed of two sets of Pca floor slabs facing each other and supported by two rows of the bearings, each of which is composed of a row of the side walls and a row of the inner walls adjacent to the side walls, and the two sets of Pca. It consists of a joint that joins both between the floor slabs,
A first step of fixing and mounting each of the two sets of Pca floor slabs on the support in a transversely facing manner;
A second slab erection method comprising: a second step in which the two sets of Pca floor slabs facing each other in the transverse direction are joined to each other by concrete placement to construct the joint, and to be fixed integrally in the transverse direction. It is a construction method of the floor slab according to claim 1,
The support is provided with a pit in a portion where the Pca floor slab is placed,
The Pca floor slab supports the Pca floor slab in the transverse direction, with a first through hole penetrating to the support portion of each of the side wall and the adjacent middle wall below the Pca floor slab with the transverse direction as the front. A reinforcing bar projecting to the joint at a position beyond the end of the inner wall that is the bearing
The first step includes
Temporarily dropping the drop bar into the drop hole through the first through hole and temporarily fixing the Pca floor slab to the support;
Extracting the drop bar, inserting an anchor bar into the first through hole, filling the first through hole with mortar, and fixing.
The second step includes
A method for laying a floor slab, characterized in that the joint is constructed by joining by a concrete placement including a lap joint formed along the reinforcing bar and a cross bar placed on the lap joint. It is a construction method of the floor slab according to claim 2,
The Pca floor slab includes a second through hole in the vicinity of a side end portion on the adjacent middle wall side,
The first step further comprises:
Fixing the gauge plate in a transverse direction in a form in which a suspension bar is passed through the second through hole and the two sets of Pca floor slabs are passed between the gauge plates;
Laying rails in the longitudinal direction on the upper surfaces of the opposite ends of the two sets of Pca floor slabs including the top of the gauge plate.

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