JP6395767B2 - Construction structure - Google Patents

Description

  The present invention relates to an installation structure using a floor slab supported by two side wall side fulcrums continuous in the axial direction (longitudinal direction) of a tunnel and one or more middle column fulcrums, and a Pca floor slab constituting the structure , Pca middle pillar, Pca footing and floor slab joining formwork.

Conventionally, when a large-section road or railway shield tunnel is made large-sized, a floor slab that receives roadbed load has two anchors on the fulcrum side at the side wall fulcrum and the middle column fulcrum between them. An anchor bar was inserted into the through hole on the floor slab side that fits and was supported with a bearing rubber sandwiched in place with a mortar.
Here, the purpose of the bearing rubber is to form a general pin structure that allows deformation of the floor slab, thereby reducing the cross-sectional force and floor slab specifications, reducing stress concentration and fatigue durability against vibrations, etc. There is an effect of improving.

  In addition, there is no joint at the longitudinal line position, and the joint at the transverse line position is a loop joint, and a plurality of floor slabs are integrated in the axial direction (longitudinal direction). A seam is provided to form an integrated structure of an elongated rectangular structure in the axial direction (longitudinal direction) for each constant extension. Here, the loop joint has no problem in fatigue durability, but the bending performance varies depending on the shape and cannot be evaluated. In the first place, since the Pca slab is a ring-cut structure across the tunnel, a girder structure cannot be formed in the tunnel axis direction (longitudinal direction) even if the Pca floor slab is an integrated structure having a rectangular shape in the tunnel axis direction (longitudinal direction). In addition, floor slabs that receive roadbed loads are usually subjected to structural verification as a multi-span continuous beam structure in the transverse direction of the tunnel.

In many conventional Pca slabs, the side walls and inverted concrete are fixed to the segments by wrapping the shear key protruding from here with reinforced concrete, and the middle column is a simple anchor without fixing the internal reinforcing bars to the invert concrete. And fixed.
As a whole, a floor slab having a rectangular shape in the axial direction (longitudinal direction) for each fixed extension is fixed to the side wall and the middle column while being allowed to be deformed via a support rubber. It is a structure that transmits the bearing load from the invert concrete to the segment side through the side wall and the middle column. Further, the middle pillar is rectangular and forms a continuous wall. In short, the individual members are stacked in order.

  With such a configuration, each member may be subjected to design verification separately, and it is not necessary to perform design verification as the entire structure, thereby simplifying the design. Furthermore, the bending stress does not reach the segment that is the earth pressure load bearing body, and the tunnel lining structure is stabilized. Against this background, the floor slab structure in the tunnel does not have to take into account the influence of seismic motion, so that there is no problem even if the individual members are stacked one after another.

In order to compare the prior art and the present invention, the structural comparison between the Pca floor slab and the middle pillar between the two diameters and the three diameters is shown in FIGS. 1 and 2, and the construction procedure accompanying the shield excavation is compared. 3 shows.
FIG. 1 is a diagram showing the structure of a Pca floor slab and a middle column between two diameters, and a cross-sectional view (a support part and an opening) showing the structure of a Pca floor slab and a middle column according to the prior art, and a part above the arrow, A side view is shown, and in the lower part from the arrow, a cross-sectional view (a support part and three types of openings) showing structures of a Pca floor slab and a middle pillar according to the present invention and three types of side views are shown. An example of the Pca floor slab installation structure shown here as a prior art is shown in Non-Patent Document 1.

Similarly, FIG. 2 is a view showing a Pca floor slab and a middle column structure having three diameters, and is a cross-sectional view (support portion and opening portion) and a side view of the related art and the present invention in the same form as FIG. Indicates.
The conventional Pca slab shown in FIG. 1 and FIG. 2 is supported by the side wall and the middle pillar with the bearing rubber interposed therebetween, and is divided into left and right parts, so that the anchor bars are required to be doubled on the middle pillar.

Moreover, FIG. 3 shows the construction procedure by a prior art in the upper part from the arrow about the order which builds a Pca floor slab, a center pillar, etc. with shield excavation, and relates to the present invention in the lower part from the arrow. The construction procedure is shown. In the prior art, behind the shield machine, the sleepers and rails necessary for the subsequent carriage are struck and used by turning them back.
1 to 3 will be described later in the detailed description of the invention.

Concrete engineering Vol. 49 (2011) No. 49 12 P.M. 12-40 Design and construction of tunnel segments and floor slabs in the Tokyo Metropolitan Expressway Central Shinagawa Line

  In general, when the shield tunnel has a small cross section, the Pca floor slab has a multi-girder continuous girder structure integrated in the transverse direction. However, in the case of a large cross section in which the crosswise integrated length of the Pca floor slab exceeds 10 m, it is necessary to make the Pca floor slab a divided structure between the diameters for the convenience of transportation and installation. Then, on the middle pillar, both the left and right Pca floor slabs are brought into contact with each other. Therefore, an anchor bar for fixing the Pca floor slabs is required, and the width of the middle pillar is also increased. The problem comes out.

Here, when the shield tunnel has a small cross section, the Pca floor slab is a continuous girder structure integrated in the transverse direction that allows movement on the bearing, so that the cross-sectional force and floor slab specifications can be reduced as compared with the single-diameter individual structure. Because.
However, when the shield tunnel has a large cross section, the structure in which the Pca floor slab is integrated in the transverse direction will hinder transportation and installation. Accordingly, the Pca floor slab has a single-diameter individual structure that is divided on the bearing. As a result, the cross-sectional force is increased and the anchor bars are also required to be doubled, and the thickness and width of the floor slab and the middle column are increased. This is a problem that cannot be solved because it is impossible to find a structure and construction method in which a Pca floor slab is divided and spanned by a single span and integrated in the transverse direction.

  In addition, if the Pca floor slab, which was originally cut in the transverse direction, can be rigidly connected to the Pca middle pillar, the middle pillar and the floor slab will form a large T cross section (between 2 diameters) or π cross section (3 diameters), Increased rigidity and durability. However, such an integrated structure of the middle column and the floor slab is difficult to realize because it hinders transportation and erection. This is a problem that cannot be solved because no structure or construction method has been found that can individually transport and install Pca floor slabs and Pca middle pillars and rigidly connect them.

  Furthermore, when an opening is required on the wall formed by standing the Pca middle pillar, the size and arrangement of the opening are limited because the function as a support cannot be lost, and it is difficult to install a large opening. In addition, when an opening is required in the center side slab of 3 or more spans, in the floor slab structure where the cross-section joint is joined by a loop joint in the direction of the tunnel cross section, uniform rigidity and deformation with respect to the roadbed load If the load could not be resisted, cracking and durability would be reduced. Similarly, there were restrictions on the size and arrangement of the openings, making it difficult to install large openings. This is because a structure and construction method has been found in which an opening reinforcement structure is arranged on the outer portion of the opening formed by the lack of the opening of the Pca middle pillar and the Pca floor slab, and the surrounding Pca floor slab can be rigidly connected. This is a problem that cannot be solved because it is not.

The problems of the structure of floor slabs and middle pillars used in conventional shield tunnels have been described above, and these are summarized below.
1) When a shield tunnel has a large cross section, a structure in which a Pca floor slab is divided between single diameters and integrated in the transverse direction cannot be found. Therefore, the Pca floor slabs are butt-arranged on the support, and the anchor bar and the support rubber need to be doubled, so that the sectional force increases. Therefore, the thickness and width of the floor slab and the middle pillar increase.
2) No structure or construction method can be found that can rigidly connect the Pca floor slab and Pca middle pillar in the transverse direction, and the overall rigidity cannot be increased. Therefore, the structural rationality is lacking, and the cost increases or the durability decreases.

3) In the Pca middle pillar, the upper end has a general pin structure that allows deformation by fixing the support rubber and the anchor bar, and the lower end has a pin structure by simple anchor fixing without fixing the structural bar to the invert. That is, it is customary to have a pin structure at both the upper and lower ends. Therefore, since a double-row anchor bar is required, a large inertia force is exerted on the Pca middle column that is heavier due to the earthquake motion, and the Pca middle column penetrates upward while damaging the Pca floor slab. There were structural vulnerabilities such as falling or falling.
4) In order to fix the Pca middle pillar more stably, the anchor fixing structure to the invert is used, but the footing structure that can hold the anchor is a conventional invert that has the minimum amount of reinforcing bars that can only be used to prevent cracks. Not. In the first place, it is difficult in the construction cycle to construct a footing as a construction under a narrow trailing carriage and to assemble such a reinforcing bar for the footing.

5) When the Pca middle column requires an opening, the structure of the Pca floor slab and the Pca middle column is made of a highly rigid girder structure, and this has a structure and construction method with an opening reinforcing structure that does not lose the support function. Absent. Therefore, the size and arrangement of the openings are restricted to be accommodated while providing the opening reinforcing bars in the Pca middle column, and a large opening cannot be installed.
6) If the Pca floor slab on the center side with more than 3 spans needs an opening, the structure of the Pca floor slab and the Pca middle pillar is made of a highly rigid girder structure, and the structure and construction method for opening the structure can be found. Not. Therefore, the Pca floor slab is formed by cutting the transverse line joint with a loop joint in the direction of the cross section of the tunnel and joining it with a loop joint. There is a restriction that it can be accommodated with opening reinforcement bars inside, and a large opening cannot be installed.

7) When the floor slab interposes roadbed concrete that does not receive direct wheel load, there is little damage over time. Nevertheless, it has been uneconomical to adopt an expensive bearing structure that presupposes the separation and removal and replacement of floor slabs.
8) As a floor slab, high-speed construction of a shield is common today, but the use of a Pca floor slab is normal, and there are few parts for inexpensive on-site construction, resulting in an increase in cost.

9) When making the middle pillar a rigid joint with higher rigidity and durability than the footing placed on the invert, a construction method has been found that does not hinder the segments and invert concrete transport accompanying shield excavation. The construction cost was soaring.
10) Conventionally, it has been necessary to perform invert concrete placement below the trailing carriage in order to maintain the rail used for transporting the segment to the shield machine. If this was delayed, shield drilling had to be stopped, which was a potential cause of process delay.

11) If invert concrete placement is precast in the entire area and installed immediately after the shield machine, the reciprocating segment carriage and the following carriage can also run on the rails arranged on this, and the potential factor of process delay is eliminated and efficiency is increased. The improvement was remarkable and difficult.
12) In order to maintain the rail used for transporting the reciprocating segment cart to the shield machine, a sleeper is conventionally required on the surface of the invert concrete after curing, in addition to the sleeper for running the subsequent cart, and this point is useless. there were.

13) The sleepers are installed on invert concrete to hold the rails used for transporting the reciprocating segment trolley. Since the sleepers are divided into unbroken center pillars, fixing becomes complicated and unstable. There was a danger.
14) If the floor slab is more than 3 spans, the segment transport space can be taken from the left and right. Therefore, if only the central part is constructed on site, the cost can be reduced compared to full precast. However, conventionally, the formwork support during the curing period has not been realized because it cannot be dismantled and removed from the mold, and therefore, it cannot be applied while striking a narrow space in the axial direction (longitudinal direction).

In order to solve the above problems, the floor slab and the middle pillar according to the present invention take the following means.
1) Two sets of Pca floor slabs and center pillars that are installed facing each other on two side walls on both sides and one or more center pillars adjacent to each other in the tunnel crossing direction protrude from each of the three members to the joint of the three members. A plurality of axial rebars are placed on the rebar at least in the tunnel axial direction (longitudinal direction), and then concrete is placed through the joint to form an integrated structure.
2) The floor slab is a bearing that allows deformation by sandwiching a rubber plate between the lower surface of the Pca floor slab and the upper surface of the side wall and fixing it with an anchor bar at the two side walls.

3) The two sets of Pca floor slab and the middle column are connected to the reinforcing bars protruding from the three parties to the joint of the three parties, and at the intersection of the Pca floor slab and the middle column, at least the tunnel axis direction (longitudinal direction) reinforcing bars, A girder structure in which the hoop bars arranged in the axial direction (longitudinal direction) at a predetermined interval and confined in the axial direction (longitudinal direction) are placed in the field and placed in the joint to form an integrated structure.

In order to solve the above problems, the Pca floor slab according to the present invention takes the following means.
1) The Pca floor slab has a long rectangular shape in the tunnel transverse direction, with reinforcing bars protruding at least in three directions of the transverse line side surface and the longitudinal line side surface on the middle column side, and the longitudinal axis of the middle column in the longitudinal direction of the tunnel axis. There is a loading surface for loading a Pca floor slab load at the edge of the upper surface of the middle column, although it does not reach the entire transverse direction.

2) The Pca floor slab protrudes a vertically descending wall toward the middle column at least at a predetermined width at the edge of the loading surface.
3) The Pca floor slab is pre-attached with support rubber in the side wall connection, penetrates vertically through this, and provides a through hole that matches the anchor hole provided in the side wall in advance. Secure with.

In order to solve the above problems, the Pca middle pillar according to the present invention takes the following measures.
1) The Pca middle column is composed of a support column and an overhang, and has an inverted L shape in the tunnel axis direction (longitudinal direction), and the reinforcing bar in the support column protrudes vertically upward.
2) In the Pca middle column, a haunch is arranged at the corner of the overhang, and the haunch muscle that matches the slope of the haunch cuts obliquely upward from the housing near the haunch.

3) The Pca middle column extends in the tunnel axial direction, the Pca floor slab side does not reach the entire transverse direction, but at the edge of the top surface of the middle column, the loaded surface that receives the loading surface of the Pca floor slab It has an ascending wall that restrains the falling wall of the Pca floor slab while restraining the falling wall.

4) At the upper end of the Pca middle pillar, approximately one side of a hoop line arranged at a predetermined interval in the axial direction (longitudinal direction) is embedded, and approximately three sides protrude upward.
5) The Pca middle column has, at its lower end, a reinforcing bar that can be connected to a reinforcing bar protruding from the footing side at the end of the main reinforcing bar.

In order to solve the above problems, the Pca footing according to the present invention takes the following means.
1) Pca footings are arranged intermittently at the same predetermined intervals at the place where the pillars of the middle pillars erected in the tunnel axis direction (longitudinal direction) at the predetermined intervals are supported on the lining segment side. As an arc shape, an arc-shaped surface is received on the lining segment side, and a reinforcing bar connected to the Pca middle column is arranged on the upper surface on the string side.

2) In the Pca footing, reinforcing bars that project horizontally to the in-situ invert concrete side are arranged on at least two transverse sides of the four sides.
3) The Pca footing has a thin layer of concave space inside the frame shape on the surface where the arc-shaped surface is attached to the lining segment side, and is fixed in close contact with the lining segment side by filling it with mortar after installation. To do.

In order to solve the above-mentioned problems, the floor slab joining formwork in the case of three or more spans according to the present invention takes the following means when filling up the formwork of the joint part.
1) The floor slab joining formwork is manufactured in a factory integrally with a fixed length in the axial direction (longitudinal direction), and horizontal horizontal ribs arranged at predetermined intervals in the transverse direction integral with the skin plate and the inner side of the housing side; A vertical vertical rib for loading the concrete load of the joint portion on the opposite middle pillar is arranged in a form connected to the horizontal rib via the horizontal rib. The skin plate includes a central horizontal portion, a haunch portion that is bent downward at a predetermined angle at both ends thereof, and a seating surface that is bent at a predetermined angle and is lowered downward from the upper surface of the middle column to contact the side surface of the middle column. Construct and bury with the horizontal and vertical ribs.
2) The vertical rib of the floor slab joining form is interrupted at the upper end of the middle column, and the concrete load is loaded on the opposite middle column from the end of the vertical rib.

In the present invention, two sets of Pca floor slabs that are installed facing each other, an inverted L-shaped middle column, and a footing that is erected at the same interval as the column portion of the middle column are integrally integrated. And the fulcrum of the side wall sandwiches the support rubber and allows deformation here. Thereby, the following effects can be produced.
1) Since the floor slab is formed by rigidly integrating the Pca floor slab and Pca middle pillar in the transverse direction to form a large T cross section (2 diameters) and π cross section (3 diameters), the rigidity is increased as a whole. Can streamline the structure and improve durability.
2) Since the floor slab is supported by sandwiching the support rubber between the two rows on both sides, the impact load is relaxed and no moment is generated in the support, and the durability of the floor slab and the lining segment is not impaired. .

3) The Pca floor slab can be divided between single spans, and it does not deteriorate the workability of transportation and erection even when the cross-section is large, and the intersection with the middle column is rigidly integrated. Anchor bars and support rubber are no longer needed, and cost is reduced accordingly.
4) When roadbed concrete that does not receive direct wheel load is present, the structure of the Pca floor slab of the present invention eliminates an expensive bearing structure and reduces costs in maintenance and maintenance.

5) The cost of the floor slabs is reduced because the number of inexpensive on-site joints other than the two sets of expensive Pca floor slabs installed opposite each other increases.
6) Due to the existence of two sets of Pca slabs that are installed facing each other, a reciprocating segment conveyance space can be taken downward, and a reciprocating Pca slab itself and the joint concrete conveyance space can be taken upward, and the construction work will progress. Do not delay the process.

7) Since the intersection of the Pca floor slab and the Pca middle pillar is rigidly integrated as a girder structure and serves as an opening reinforcing structure and a support, the width of the Pca middle pillar can be exceeded and a large wall opening can be installed.
8) In the case of three spans, the intersection of the Pca floor slab and the Pca middle column is made into a girder structure and rigidly integrated, and this can be used as a floor slab opening reinforcement structure. Can be installed.

9) At the joint, opposing Pca floor slabs are joined by lap joints while projecting the reinforcing bars from the side of the longitudinal line, and the reinforcing bars of the loop joint are projected from the side of the transverse line. Since the reinforcing bars protrude vertically from the middle column and are fixed in the joint, the Pca floor slabs and the middle column are firmly integrated vertically and horizontally at the joint, thereby increasing the load resistance and improving the durability.
10) Since the Pca middle pillar is erected in an inverted L-shape in the axial direction, a large opening can be provided, reducing the total amount of precast and reducing the cost.

11) When the Pca middle pillar is erected in an inverted L-shape in the axial direction, if the Pca footing that is intermittently arranged is connected to the Pca middle pillar in advance and connected to the Pca footing intermittently, the footing reinforcement quality is improved. There is no anxiety, and the structure can withstand the moment of the root.
12) A larger wall opening can be installed by providing an inverted L-shaped Pca middle column with a space for constructing the site by separating the projecting portion from the abutment (Type 3 shown in FIG. 1). In the case of three spans, a large wall opening is provided during construction, and in the completed system, if a post-work strut is post-installed at this joint, it is combined with the central floor slab opening and the roadbed on the floor slab after reaching the shield In the construction of machinery and equipment, the material delivery route can be installed freely, shortening the entire construction process.

  The Pca slab according to the present invention has a loading surface for loading on the upper surface of the middle column, and the loading surface is horizontally arranged with a predetermined width from the side surface position of the middle column, and descends vertically down to the predetermined width at the edge thereof. The wall protrudes toward the middle column, and a support rubber is disposed in advance in the side wall connection, and the anchor bar is inserted into the through hole on the floor slab side and the anchor bar hole on the side wall side and fixed. Further, the Pca middle column according to the present invention has an inverted L-shape, and the internal reinforcement of the support column protrudes vertically upward and the hunched muscle protrudes obliquely upward, and the loading surface of the Pca floor slab on the upper surface edge. And an ascending wall that restrains the descending wall of the Pca floor slab. From the above structure, the following effects can be obtained.

13) Since the position of the descending wall of the Pca floor slab is constrained by the ascending wall of the Pca middle column, if the anchor bar is inserted into the anchor bar hole and the through hole on the floor slab, the Pca floor slab may fall off from here. And work safely.
14) Since the loading surface of the Pca floor slab is supported by the loading surface on the upper surface of the rising wall of the Pca middle column, it is possible to reliably hold the load associated with the transportation construction of the Pca floor slab itself.

15) Since the descending wall of the Pca floor slab can protrude between the hoop bars constituting the girder structure at the intersection with the middle column and the axial reinforcing bar inscribed, the width of the hoop bars is maximized and the rigidity of the girder is increased. Maximum durability and improved durability.
16) Since the inner column of the Pca is fixed by projecting the internal muscle vertically upward in the narrow portion of the hoop that forms the girder structure at the intersection with the Pca floor slab, it can be firmly joined and the durability is improved.

17) The inverted L-shaped Pca middle column has a hunch on the corner of the overhanging part that protrudes in the shape of a chianti, and the haunch muscles that match the slope of the corner of the hunch Since it protrudes more diagonally upward, cracks appearing at the corners of the opening can be effectively prevented.
18) When the multi-diameter integral Pca floor slab can be installed in a transverse direction such that the span of the floor slab is less than 10 m, the upper wall of the upper end of the inverted L-shaped Pca middle pillar is arranged at both ends of the upper surface, If the inside of the upper surface is a U-shaped space, and an axial rebar is placed on the upper concrete and both mounting surfaces are configured as a continuous support, a Pca floor slab is installed here via a rubber plate. it can. This eliminates the need for a connecting portion and further shortens the construction period.

19) If the shape of the overhanging portion of the Pca middle pillar that protrudes in the shape of a chianti is substantially arched, it is possible to omit hunched streaks and opening reinforcing bars due to the arch action effect.
20) Even if it is an inverted L-shaped Pca middle pillar that forms a large opening, if a mortar-filled sleeve joint is arranged at the lower end of the internal vertical bar at the lower end of the support part, the vertical bar on the upper surface of the Pca footing It can be included and fixed here, and the base can be made into a strong rigid structure that bears the bending moment, thereby improving the durability.

21) The inverted L-shaped Pca middle column is a temporary mortar-filled sleeve joint that is bolt-bonded between the Chianti-like overhanging portions and the back-to-back strut portions in the tunnel axis direction (longitudinal direction). If it is erected continuously while being fixed, it can be a middle pillar having a large opening rather than a simple inner wall, and the precast volume can be reduced and the cost can be reduced.
22) The Pca middle column is embedded in the upper end of approximately one side of a hoop line arranged at a predetermined interval in the tunnel axis direction (longitudinal direction), and approximately three sides are fixed in the girder structure included in the joint portion. By doing so, it is possible to reduce the labor for assembling the hoop bars at the site, and in the tunnel axial direction (longitudinal direction), a plurality of axial reinforcing bars inscribed in the tunnel axis direction (longitudinal direction) can be easily placed on-site, thereby saving labor.

  The Pca footing according to the present invention is intermittently arranged in the tunnel axial direction (longitudinal direction), has a substantially arc shape in the transverse direction of the tunnel, an arcuate surface is touched on the lining segment side, and the upper surface on the chord side is Pca Reinforcing bars connected to the internal reinforcement of the middle column are arranged. Thereby, Pca footing can have the following effects.

23) Since it is placed on the arcuate inner surface of the segment, it is stable, and as long as the distance is matched, the position is determined when installed horizontally, so the installation efficiency is good.
24) It can be easily installed immediately after the shield machine, and sleepers and rails can be easily installed on its upper surface. Therefore, the subsequent carriage and the segment carriage can immediately travel here, and both sleepers can be shared, so that the work associated with shield digging is made more efficient. Also, if the sleeper in the axial direction (longitudinal direction) supported by the lower surface of the sleeper and supported by the footing is fixed to the insert provided in the footing in advance, the position of the footing can be set correctly (below the arrow in FIG. 3). Side part, see).

25) Since it arrange | positions at the same predetermined space as the support | pillar part of a Pca middle pillar, complicated footing arrangement and construction work are minimized by precasting, and a construction period is shortened.
26) Since the single unit is expensive, it is arranged to the minimum necessary with respect to the pillar part of the Pca middle wall, and its narrowness is made of inexpensive on-site invert concrete, thus suppressing the increase in cost and structural features To improve.

27) By placing a reinforcing bar connected to the internal reinforcement of the middle column on the upper surface, the middle column can be rigidly connected here and integrated with the middle column to form a rigid, inverted T-shaped floor slab support structure that is durable Improves.
28) As a stable inverted T-shaped floor slab support structure, a structure in which a slim Pca middle column and a Pca footing having a low center of gravity and intermittently placed on-site in-place concrete are rigidly connected is constructed. adopt. In addition, by fixing the Pca footing to the lining segment via a shear key of cast-in-place concrete that is integrated with the lining segment, the bending moment is not transmitted in the lining segment, and the bearing load is stably distributed. Can be transmitted, and durability is not impaired. In addition, the inverted T-shaped floor slab support structure is not separated from the lining segment even in a direct earthquake by this shear key, and the Pca center column rigidly connected to the Pca footing is slim and lightweight. Do not break through.

29) The Pca footing has four side surfaces, at least two of the transverse sides are integrated into the cast-in-place concrete that is integrated with the lining segment and the shear key, and the reinforcing bars to be connected and fixed are projected and integrated together. Therefore, the footing is stabilized without sliding. Here, when the size of the Pca footing is small and the in-place inversion rebar is necessary on the side, the rebar connected to the four side surfaces may be arranged. Moreover, this can reduce the precast total amount and reduce the cost, and the in-situ invert rebar assembly becomes efficient.
30) A thin layer of recessed space is provided on the inner side of the frame shape on the arcuate surface that contacts the lining segment side, and this is filled with mortar after installation. Thereby, even if there is a step in the lining segment, the lining segment can be adhered and fixed, the footing is stably supported, and structural weak points such as stress concentration are not generated here.

  The floor slab joining formwork in the case of three or more spans according to the present invention has a skin plate integral with a fixed length in the tunnel axis direction (longitudinal direction) and a horizontal rib disposed on the inner side surface when the joint is to be buried. And vertical ribs connected to the horizontal ribs, the vertical ribs are supported by the middle pillars by being missing at the upper ends of the middle pillars, and the skin plate is a seating part that meets the central horizontal part, the haunch parts at both ends, and the middle wall And consists of And since a floor slab joining formwork is buried, it can have the following effects.

31) Since the vertical rib is interrupted and supported at the upper end of the middle pillar, the concrete load can be loaded on the middle pillar here, and the formwork support work can be omitted. Also, it forms a T-shape in plan view with the skin plate seating surface, and breaks in the middle of the skin plate seating surface and at the upper surface of the middle pillar. If the support jack is arranged horizontally on the surface, the floor slab joining formwork will not fall off from the middle pillar, and the load due to concrete placement can be stably held (see FIG. 14).

32) Since the skin plate and the horizontal horizontal rib integral with the skin plate can be arranged at the outermost edge of the beam cross section at the joint as the structural material, the structural rationality is excellent, the bar arrangement work is minimized, and the construction period is shortened.
33) The horizontal rib has a rebar hole lined up horizontally in the in-situ floor slab part included in the joint part, and the inside of the horizontal rib extends beyond the width of the Pca floor slab, and the axial rebar is penetrated. Since the fixing of the reinforcing bars protruding from the end of the Pca floor slab and the upper end of the middle column is accepted, the opposing Pca floor slab and the middle column are rigidly connected to constitute a rational RC structure having a π cross section.

34) Conventionally, since the formwork support work during the curing period cannot be dismantled / demolded, it is impossible to perform the work while turning the space in the narrow axial direction (longitudinal direction) and returning it. However, the horizontal rib and the vertical rib connected thereto can support the concrete load of the joint at the upper end of the middle column, and support work is not required, and an inexpensive on-site construction is possible at the joint.
35) The floor slab joining formwork can be made to the burying method of the present invention capable of high-speed construction when there is no allowance in the construction period and delay in shield digging. A conventional formwork support system can be adopted and it can flexibly respond to process conditions.

FIG. 1 is a diagram showing a structure of a Pca floor slab and a middle column between two diameters in the related art and the present invention. FIG. 2 is a diagram showing a structure of a Pca floor slab and a middle column between three diameters in the related art and the present invention. FIG. 3 is a diagram for explaining the order in which the Pca floor slab, the middle pillar, and the like are constructed with the shield excavation in the related art and the present invention. FIG. 4 is a diagram illustrating a process of a construction procedure accompanying shield excavation. FIG. 5 is a diagram showing a Pca footing, a Pca middle column, and a Pca floor slab according to the present invention. FIG. 6 is a view showing a state of assembly in which a Pca middle column is placed on a Pca footing and standing, and a configuration example of another Pca middle column. FIG. 7 is a view showing a state of assembly in which the Pca floor slab is placed on the Pca middle column. FIG. 8 is an enlarged view of the assembly in which the Pca floor slab is placed on the Pca middle column. FIG. 9 is a schematic diagram showing steps of “installation of Pca footing”, “installation of sleepers and rails”, and “passage of subsequent carriage and side wall construction”. FIG. 10 is a schematic diagram showing the steps of “invert concrete placement” and “Pca middle column placement”. FIG. 11 is a schematic diagram showing the steps of “Pca middle column installation”, “Pca floor slab installation”, and “joint beam assembly and ring joint reinforcement assembly”. FIG. 12 is a diagram showing “assembly of the joint section and assembly of the joint floor slab”, “placement of joint concrete” and “removal of sleepers and placement of invert concrete on both sides”. . FIG. 13 is a view showing the structure of the joint form of the floor slab. FIG. 14 is an enlarged view of a state in which a joint floor slab is provided in the center portion between the three diameters.

  As a mode for carrying out the present invention, an embodiment according to the present invention will be described by taking a case of three spans as an example with reference to the drawings. In addition, the floor slab, the middle column, the footing, and the floor slab joining formwork according to the present invention will be described together while explaining the construction procedure associated with the shield excavation based on FIG. 4 and FIGS. To do.

  In the case of two spans, as shown in the lower part of the arrow in FIG. 1, the Pca floor slab is installed on the middle pillar, and then the intersection is rigidly integrated to form a large T section. To do. In the case of three spans, as shown in the lower part of the arrow in FIG. 2, the Pca floor slab is installed on the middle pillar and then the intersection is rigidly integrated to form a large π cross section. It is. Therefore, even between the two diameters and the three diameters, the anchor bar is unnecessary, the inner wall width is halved, the rigidity is increased, and an opening corresponding to the rigid rigidity can be provided.

  Furthermore, as shown in the lower part of the arrow in FIG. 3, the present invention occurs at the base of the middle column that is required as a result of rigid integration of the Pca floor slab, the Pca middle column having an opening, and the Pca footing. A Pca footing 27 for withstanding bending moment and axial force is installed behind the shield machine. Therefore, by the construction procedure of the Pca middle column 7 and the Pca floor slab 1 starting from this, the work of placing the invert concrete 40 in the narrow space of the Pca footing 27, omitting the hitting of the sleepers and rails necessary for the subsequent carriage, It is possible to increase the compatibility with shield excavation and prevent process delay, such that the shield excavation process does not affect the delay and can be performed behind the succeeding carriage.

  FIG. 4 is a process diagram showing a procedure for constructing a floor slab, a middle column, etc. according to the present invention with shield excavation, and corresponds to the procedure (number) shown in the part below the arrow in FIG. . 9 to 12 show specific schematic diagrams relating to the steps described in (1) to (11) in FIG. 4. In FIG. 9, (1) to (3) and FIG. 4) and (5), FIG. 11 shows (6) to (8), and FIG. 12 shows (9) to (11) in order. Hereinafter, each process is demonstrated in order along them.

(1) Installation of Pca footing As a first step, as shown in FIG. 9 (1), the Pca footing 27 is installed on the upper surface of the lower lining segment 39 in the tunnel.
The structure of the Pca footing 27 installed here is shown in FIG.

  As shown in FIG. 5 (a), the Pca footing 27 is intermittent at the same predetermined interval at the place where the column portion of the Pca middle column 7 standing at a predetermined interval in the tunnel axis direction (longitudinal direction) is joined to the invert. To place. Further, the Pca footing 27 has a generally arcuate shape, the arcuate surface 23 is abutted on the lining segment side, and the reinforcing bar 24 connected to the Pca middle column 7 is projected upward on the string side upper surface. Deploy. By connecting the reinforcing bar 24 to the Pca middle column 7 in a rigid connection, the Pca middle column 7 is rigidly coupled and integrated. A mortar-filled sleeve joint or the like is effective for the rigid connection, but a screw-type mechanical joint may be used.

  The Pca footing 27 is provided with a thin-layer recess space 25 on the inner side of the frame shape on the arcuate surface 23 that contacts the lining segment side. By filling the recessed space 25 with mortar after installation, even if there is a step in the lining segment, it can be adhered and fixed. Here, the mortar filling is performed by piping the injection pipe to the lowermost end of the recessed space 25 in advance, and preventing the frame-shaped outer edge from leaking by caulking. The injection tube is filled at once with a mortar pump (not shown).

Further, on the side surface of the Pca footing 27, a reinforcing bar for connecting to the in-situ invert is horizontally projected in the transverse direction and the axial direction (longitudinal direction). FIG. 5A shows a configuration in which the reinforcing bars protrude from the four side surfaces when the size of the Pca footing 27 is small, but the reinforcing bars are provided at least on two side surfaces in the transverse direction.
The Pca footing 27 can be easily installed immediately after the shield machine, and sleepers and rails can be immediately installed on the upper surface thereof.

(2) Installation of sleepers and rails As shown in FIG. 9 (2), sleepers and rails (rails) are installed on the Pca footing 27 installed in (1) as the next step.
In the case of (2) in FIG. 9, the sleepers are supported by the central sleeper 34 and the side sleepers 33 on both sides that penetrate the tunnel, and the lower end of the central sleeper 34 and abut on the upper surface of the Pca footing. A sleeper 35 (hereinafter referred to as “longitudinal sleeper 35”. Refer to the lower part of FIG. 3 for the longitudinal sleeper 35) and a side sleeper. And a sleeper support material 36 for supporting the 33 from the lining segment 39 of the tunnel.

  Then, in the case of three spans, the portion where the Pca footing 27 is missing is not stable because the longitudinal sleeper 35 cannot be supported by contact with the upper surface of the Pca footing, so the side sleeper 33 is supported from the tunnel lining segment 39. The sleeper support material 36 to be used is required.

  On the other hand, in the place where the Pca footing 27 exists, the central sleeper 34 interferes with the installation of the Pca middle pillar. Therefore, the central sleeper 34 is removed at the stage of the Pca support installation. Therefore, similarly, since it lacks stability, the sleeper support material 36 for supporting the side sleepers 33 from the tunnel lining segments 39 is required.

In other words, there is no problem in installation because the central sleeper 34 can be separated from and removed from the side sleepers 33 on both sides where the central sleeper 34 interferes with the installation of the Pca middle pillar. The places that do not hinder the installation of the Pca middle pillar can be arranged as they are in the crossing as they are, so that the rails in the outward path can always be held stably.
In addition, these sleepers are used in the form of a combination of the following carriage and the material carriage.

  Further, by fixing the longitudinal sleeper 35 arranged in the axial direction (longitudinal direction) in contact with and supported by the upper surface of the Pca footing to the fixing insert arranged at a predetermined position on the upper surface of the Pca footing, as a result, the Pca footing 27 is obtained. Improve installation accuracy and ensure quality, such as level, crossing position and mutual spacing.

(3) Passing of subsequent carriage and construction of side wall As the next step, as shown in (3) of FIG. 9, the subsequent carriage passes on the rail laid in (2), and on both wall surfaces of the tunnel Build the side walls.

(4) Placing Invert Concrete As the next step, as shown in (4) -1 in FIG. 10, the invert concrete 40 including the bar arrangement is placed. That is, in (4) -1, the invert concrete 40 is located below the opening (see FIGS. 5B and 6 in FIG. 5) where the Pca footing 27 is not disposed and on the protruding portion 9 side of the Pca middle column 7. (See the lowermost figure in FIG. 3). On the other hand, (4) -2 shows a situation in which the invert concrete 40 is not placed due to the presence of the Pca footing 27 rigidly connected to the support column 8 of the Pca middle column 7.

(5) Installation of Pca middle pillar As a next step, as shown in FIG. 10 (5), the Pca middle pillar 7 is installed on the Pca footing part. The Pca middle pillar 7 transported using the material carriage is lifted using the Pca middle pillar installation crane and moved in the transverse direction, placed at a predetermined position on the Pca footing 27, and installed in the Pca. The pillar is temporarily fixed by temporarily fixing a mortar-filled sleeve joint while bolting the overhanging parts in the tunnel axis direction (longitudinal direction) and the back-to-back strut parts to the pillar. To do.
Here, the structure of the Pca middle column 7 and the assembly of the Pca middle column 7 to the Pca footing 27 will be described.

  FIG. 5B shows the structure of the Pca middle pillar 7. The Pca middle column 7 is composed of a column portion 8 and an overhang portion 9, and has an inverted L shape in the tunnel axis direction (longitudinal direction). As shown in the lower side of the arrow in FIGS. 1 to 3, the opening portion can be formed by fastening the column portion 8 back to back in the tunnel axis direction (longitudinal direction) and the overhanging portion 9 butting together with a bolt. Form. Since the back-to-back portion and the butting portion are formed so as to mesh with each other in plan view and unevenness, if they are fastened with bolts, they are no longer misaligned.

Further, the Pca middle column 7 has a haunch 11 disposed at the corner of the overhanging portion 9, and a haunch muscle 12 that matches the slope of the corner of the haunch 11 protrudes obliquely upward from the housing near the haunch. It has a structure to do. This has the effect of suppressing the occurrence of cracks at the opening corners.
In addition, an internal reinforcing bar protrudes vertically upward from the column part. Thereby, rigid connection with the girder structure included in the vertically upper joint is performed.

  On the upper surface of the Pca middle column 7, hoop bars 5 erected in the vertical direction are arranged at predetermined intervals in the tunnel axis direction (longitudinal direction) with their lower ends buried. Thereby, after installation of the Pca floor slab, a plurality of axial rebars inscribed in the hoop bar can be easily placed on-site beyond the width of the Pca floor slab, thereby saving labor.

  In addition, although mentioned later, it has the to-be-loaded surface 20 which receives the loading surface 14 of Pca floor slab 1 in the upper surface edge of the Pca floor slab side of Pca middle pillar 7 (refer FIG. 8). Further, below the loading surface 20 of the Pca middle column 7, there is an upward wall 21 that restrains the downward wall 16 of the Pca floor slab 1 and prevents the Pca floor slab 1 from falling off (see FIG. 8).

FIG. 6 shows a state of assembly in which the Pca middle column 7 is placed on the Pca footing 27 and is erected.
As shown in FIG. 6, the Pca middle column 7 is erected on the Pca footing 27 in such a manner that the reinforcing bar 24 on the Pca footing 27 is inserted into the cylindrical sleeve joint 26 provided on the column 8 of the Pca middle column 7. And temporarily fix.

  Next, although not shown in the figure, the Pca middle pillar 7 is placed on a Pca footing upper spacer whose level is adjusted in advance, and the adjacent Pca middle pillars 7 face each other with the strut portion 8 back to back and the overhang portion 9 abutting each other. And fasten with bolts. Thereby, it can install correctly in a design position and a position is decided.

(6) Fixing the Pca middle pillar As the next step, as shown in FIG. 11 (6), the Pca middle pillar 7 is permanently fixed to the Pca footing part.
The rebar 24 on the inserted Pca footing 27 is joined to the cylindrical sleeve joint 26 provided in the column portion 8 of the Pca middle column 7 by filling the non-shrink mortar therein.
At the same time, filling the non-shrinkable mortar into the gap formed by the spacer (not shown) on the Pca footing completes the operation of permanently fixing the Pca middle column 7 to the Pca footing portion.

(7) Installation of Pca floor slab As the next step, as shown in FIG. 11 (7), two sets of Pca floor slabs 1 facing both sides are installed in such a manner that a Pca middle column and a side wall are passed. Using the crane for Pca floor slab installation, the Pca floor slab 1 transported using the material carriage is moved in the transverse direction, and both ends in the transverse direction of the Pca floor slab 1 are the Pca middle column 7 and the side walls on both sides, respectively. Install it so that it rests on top. Here, the side wall on both sides is a support that allows deformation by sandwiching the support rubber. As a result, the segment does not receive an impact load.
Here, the structure of the Pca floor slab 1 and the assembly of the Pca floor slab with respect to the Pca middle column 7 will be described.

  FIG. 5C shows the structure of the Pca floor slab 1. The Pca floor slab 1 has a longitudinal rectangular shape in the tunnel transverse direction, and has reinforcing bars protruding from at least three sides of the transverse line side surface and the longitudinal line side surface 1 side of the Pca middle column side, and is provided at the end of the Pca middle column side. 8, the loading surface 14 (not the entire upper surface of the middle column) having a predetermined width horizontally from the middle column side surface position with respect to the Pca middle column 7 and descends while projecting vertically to the Pca middle column side A descending wall 16 having a shape is provided.

  Further, the Pca floor slab 1 is provided with a support rubber (not shown) in advance in the side wall connection, and is provided with a through hole 2 that vertically penetrates this and fits an anchor hole (not shown) provided in the side wall in advance. At the time of installation on the side wall, anchor bars are arranged through the through holes 2 at a predetermined pitch in accordance with structural needs and fixed by mortar filling.

  FIGS. 7 and 8 (enlarged circles in FIG. 7) show how the Pca floor slab 1 is mounted on the Pca middle pillar 7. The loading surface 14 on the lower surface side of the Pca floor slab 1 is placed and supported on the loaded surface 20 on the upper surface of the rising wall 21 provided on the Pca floor slab side of the Pca middle column 7. Here, if an anchor bar is arranged in the through hole 2 that fits to the anchor hole (not shown), the position of the descending wall 16 of the Pca floor slab 1 is no longer constrained by the ascending wall 21 of the Pca middle column 7. The Pca floor slab 1 does not fall off. Further, since the loading surface 14 and the loaded surface 20 are continuous in the axial direction, the concrete at the joint portion does not leak from here. Furthermore, since the downward wall 16 has a predetermined axial width and a shape that protrudes vertically to a predetermined location while projecting toward the Pca middle column, it avoids obstacles to both the hoop at the upper end of the Pca middle column and the inward axial beam. It can maximize the width and girder stiffness of the hoop and improve durability.

(8) Assembly of joint girder reinforcement and ring joint reinforcement As the next step, as shown in FIG. 11 (8), the girder and ring joint are formed at the joint between the Pca floor slab 1 and the Pca middle column 7. Assemble the streaks.
As shown in the right side view of FIG. 7 and FIG. 8 (an enlarged view of the circled portion of FIG. 7), the downward wall 16 on the lower surface side of the Pca floor slab 1 is inserted into the narrow part of the hoop muscle 5 of the Pca middle column 7. However, the loading surface 14 is allowed to rest on the loaded surface 20. After that, by incorporating a plurality of axial rebars inscribed in the hoop bar 5 at the upper end of the Pca middle column 7 and a ring joint bar in the transverse direction of the Pca floor slab, the girder structure 6 is configured in the joint in the axial direction. In the transverse direction, a girder structure of the ring joint portion is formed, and a reinforcing bar protruding upward from the column portion of the Pca middle column is received here, so that the intersection of the Pca floor slab 1 and the Pca middle column 7 is rigidly connected. Join.

In addition, when the span of the floor slab is less than 10 m and a multi-diameter integrated Pca floor slab can be installed at once in the transverse direction, as an example of the configuration of the Pca middle column 7, the rising wall at the upper end of the inverted L-shaped Pca middle column Can be arranged on both ends of the upper surface, and the inside of the upper surface can be a U-shaped space. FIG. 6B shows a configuration example in this case. Then, if the upper concrete is placed in this U-shaped space, and the both mounting surfaces are configured as continuous supports, a Pca floor slab can be installed here via a rubber plate. .
Furthermore, if the shape of the overhanging portion of the Pca middle pillar that projects into a chianti shape is substantially arched, it is possible to omit hunched streaks and opening reinforcing bars due to the arch action effect. FIG. 6C shows a configuration example in this case.

(9) Assembling the joint form and assembling the joint floor slab As the next step, as shown in FIG. The plate joint formwork 32 is assembled, followed by the joint floor slab reinforcement.

  FIG. 13 shows the structure of the joint slab 32 of the floor slab. The floor slab joining formwork 32 is integrally manufactured at a factory in a certain length in the axial direction (longitudinal direction). The skin plate 28 is a structure including a central horizontal portion, a haunch portion that is bent downward at a predetermined angle at both ends thereof, and a contact surface 31 that is bent at a predetermined angle and contacts the side wall of the middle pillar. Will be buried.

A plurality of horizontal ribs 29 are provided in parallel with a predetermined interval in the axial direction (longitudinal direction) with respect to the skin plate 28 in the horizontal direction, and a plurality of vertical ribs 30 are provided in the vertical direction with respect to the skin plate 28 in the vertical direction. A parallel rib 29 is connected in parallel.
The lower end of the vertical rib 30 is missing on the upper surface of the middle pillar. Thereby, the floor slab joining formwork 32 is restrained by the lower end of the vertical rib 30 and the contact surface 31 of the skin plate, and does not fall off from the Pca middle column 7.

  Further, the horizontal rib 29 arranged across the tunnel has reinforcing bar holes of a predetermined interval, and the reinforcing ribs are arranged by passing through the lower reinforcing bars of the double reinforcing bars which are the axial reinforcing bars of the floor slab of the joint. The upper bar is arranged in the upper part, and the fixing of the reinforcing bar protruding from the opposite end of the Pca floor slab and the upper end of the middle column is accepted.

  FIG. 14 shows an enlarged view of the joint floor slab provided at the center between the three diameters. In order to prevent the joint formwork 32 at the center of the three diameters from falling off, a support jack 38 is disposed on the reception portion and restrained.

After (8) “Assembly of joint girder reinforcement and ring joint reinforcement” described above, (9) “Assembly of joint form” and subsequently “Assembly of joint floor slab” are performed. As a procedure, “Assembly of joint girder reinforcement and assembly of ring joint reinforcement” can no longer be assembled after “Assembly of joint form” and cannot be assembled. “Assembly of the joint formwork” means that the axial rebar of the joint floor slab penetrates through the horizontal ribs of the joint formwork. Can not.
In addition, the joint floor slab reinforcement is a transverse direction in which the lower joint in the axial direction penetrating the horizontal rib of the joint formwork and the upper reinforcement above and the double reinforcing bars protruding from the opposing Pca floor slabs are connected by a lap joint. Assemble the reinforcing bars in order from lower to upper.

(10) Placing the joint concrete As the next step, as shown in (10) of FIG. Here, since the loading surface 14 and the loading surface 20 are continuous in the axial direction, the concrete at the joint portion does not leak from here.

(11) Removal of sleepers and placement of invert concrete on both sides As the last step, as shown in (11) of FIG. To cast. In the above-mentioned “4. Placement of invert concrete”, the narrow gap of the Pca footing 27 disposed intermittently has been placed during shield excavation. If necessary, finished concrete having a required thickness may be placed on the side and upper surfaces of the Pca footing 27 and the inverted concrete 40. These placements are often performed after reaching the shield.

1 Pca floor slab, 2 through hole, 5 hoop, 6 digit structure, 7 Pca middle pillar,
8 struts, 9 overhangs, 10 reinforcing bars (projecting vertically upward), 11 hunches,
12 haunch muscles (projecting obliquely upward), 14 loading surface, 16 descending wall, 20 loading surface,
21 ascending wall, 23 arc-shaped surface (reception), 24 rebar (string side upper surface),
25 thin layer recessed space, 26 cylindrical sleeve joint, 27 Pca footing,
28 skin plates, 29 horizontal ribs, 30 vertical ribs, 31 reception surfaces,
32 floor slab joint formwork, 33 side sleepers, 34 center sleepers, 35 longitudinal sleepers,
36 sleeper support, 38 support jack,
39 Lining segment, 40 Invert concrete

Claims (2)

A middle column that is installed adjacent to one or more rows in the transverse direction of the tunnel, and has a hoop line that is arranged on the upper surface of the tunnel at a predetermined interval in the axial direction of the tunnel and that has a lower end embedded in the upper surface and stands vertically .
Two sets of Pca floor slabs installed across the middle pillar and the side walls on both sides of the tunnel;
A plurality of axial rebars having a length exceeding the axial width of the tunnel of the Pca floor slab and arranged in the axial direction of the tunnel inscribed in the hoop reinforcement, and the two sets of Pca floor slabs An erected structure in which the intermediate column and the joint portion of the Pca floor slab formed by concrete placement are integrated with a reinforcing bar protruding from the side face of the tunnel facing each other . The erection structure according to claim 1,
The installation structure according to claim 1, wherein the fulcrum on the side wall is a support fixed by an anchor bar with a support rubber interposed between the lower surface of the Pca floor slab and the upper surface of the side wall.