JP5240723B2 - Arch culvert construction method and construction structure used in the construction method - Google Patents

Description

  The present invention relates to a method for constructing an arch culvert used as a structure such as a protruding shaft of a tunnel.

  In consideration of the compatibility with the surrounding terrain, the tunnel gate is preferably a protruding type. There are various types of projecting type tunnels, such as the bamboo split type and the bell mouth type, but all are arch type concrete structures that project from the natural ground where the tunnel is formed. On the other hand, a concrete structure having an arch-shaped cross section exposed on the ground surface is usually called an arch culvert, but in the present invention, a protruding shaft of a tunnel is also regarded as a form of an arch culvert. .

  In arch culvert construction, a formwork is generally used, and concrete is placed in the formwork. However, it takes time and labor to assemble the formwork at the construction site. Therefore, a technique for reducing labor and time required for work related to the formwork such as assembly of an external scaffold has also been proposed. For example, Japanese Patent Application Laid-Open No. 2003-82993 discloses a technique in the direction of a tunnel. There is an outer mold formed by connecting a plurality of divided small units in a tunnel direction. According to this outer formwork, it is possible to quickly assemble the side part and the top part, which are completed in advance as the constituent elements of the small unit, only by assembling at the site of the tunnel construction.

  On the other hand, at the construction site where there is a lot of spring water, when the concrete structure is completed, it is necessary to separately construct the drainage around its periphery. However, in order to perform such construction, it is necessary to wait for the concrete to harden, and it is also necessary to reassemble the external scaffold. Therefore, as a construction method for solving these problems, for example, in Japanese Patent Application Laid-Open No. 10-159073, a waterproof sheet is laid on a casing forming sheet made of a flexible sheet, and the casing forming sheet is used. An arch culvert construction method is disclosed in which concrete is placed on the outer periphery of a waterproof sheet by inflating with a waterproof sheet by air pressure. According to this construction method, since the waterproof sheet can be laid before the casing forming sheet is inflated into an arch shape and the formwork is formed, a work scaffold for constructing the waterproof sheet becomes unnecessary. Moreover, since the waterproof sheet is in an integrally joined state with the arch-shaped skeleton concrete formed by spraying concrete on the outer periphery thereof, the placement of the arch-shaped skeleton concrete and its waterproofing work are performed simultaneously. .

JP 2003-82993 A Japanese Patent Laid-Open No. 10-159073

  However, the outer mold formed of the small units has a problem that the time and labor required for manufacturing the small unit are required although the time and labor required for the assembly work at the construction site are reduced. Moreover, since the small unit is shape | molded previously, there also exists a problem that it is inferior to the applicability in a construction site. And in an actual construction site, the board | plate material for spraying surface formation is installed on the outer side as a formwork, and the method of constructing spraying concrete on the spraying surface is taken. However, this construction method has a problem that the formation of the sprayed surface is construction from the outside, and an external scaffold is still necessary. In addition, steel corrugated plates are widely used as the plate material for spraying surface formation. However, the work of installing steel corrugated plates in the construction of projecting tunnels is a crane operation on steep slopes, which makes it safer. There was also a problem, and there was also a landscape problem due to the rusting of the corrugated steel plate.

  On the other hand, in the construction method in which the casing forming sheet is inflated with the waterproof sheet by air pressure, a sealed space is formed between the base concrete and the casing forming sheet in order to inflate the casing forming sheet with the waterproof sheet by air pressure. There is a need. However, it is not easy to airtightly fix the casing forming sheet to the base concrete, and there is a possibility that it takes more time and labor than when the work scaffold is assembled. Moreover, in this construction method, when it became necessary to perform drainage countermeasure construction on the outer periphery of the concrete structure, there was still a problem that an external scaffold was still necessary.

  Therefore, the present invention provides an arch culvert construction method that can easily perform shotcrete placement and drainage construction on its outer periphery without assembling an external scaffold, and without damaging the landscape. Objective.

  In the arch culvert construction method according to the present invention, a plurality of support structures having an H-shaped cross-section are installed at intervals with the flanges being parallel to the arch culvert tunnel to be constructed. Further, a water guide sheet and a net that covers a surface of the water guide sheet that is directed to the inside of the constructed arch culvert are arranged on an inner surface of the flange where the water guide sheet is disposed from outside the constructed arch culvert. It arrange | positions in the state which touches and closes the space | interval of the said support work. And after spraying spray concrete to the site | part with which the said water conveyance sheet | seat and the said net | network overlap with the said flange, the said spray concrete is sprayed over the said net | network body with respect to the said water conveyance sheet | seat.

  Before spraying the shotcrete, the surface of the water guide sheet that closes the space between the support works and that faces the outside of the constructed arch culvert may be pressed with a wire extending in the circumferential direction.

  The construction structure for an arch culvert according to the present invention includes a support having an H-shaped cross section, a water guide sheet, and a net covering a surface directed to the inside of the arch culvert on which the water guide sheet is constructed. A plurality of the supporting works are installed with the flanges in a direction parallel to the constructed arch culvert tunnel and spaced apart from each other. The water guide sheet and the net are installed in a state in which the water guide sheet is in contact with an inner surface of the flange portion disposed outside the constructed arch culvert. And the space | interval of the said support work is block | closed with the said water guide sheet and the said net | network.

  A surface of the water guide sheet that is directed to the outside of the constructed arch culvert may be pressed by a wire extending in the circumferential direction.

  In the present invention, the water guide sheet is a sheet body that absorbs water and includes a gap in which the absorbed water can be moved by gravity. Considering durability against concrete spraying, for example, a single layer structure Nonwoven fabric is preferred.

  In the construction method of the arch culvert according to the present invention, the water guide sheet functions as a surface corresponding to the sprayed surface of the shotcrete formed by the steel corrugated plate or the like in the conventional construction method. And since this water conveyance sheet | seat is lighter than a steel board | plate material, it can install easily in a construction site, without assembling an external scaffold and using a crane etc. Moreover, a water conveyance sheet | seat is integrated, without peeling from sprayed concrete via the net | network which covers the surface. Therefore, the shotcrete is subjected to drainage measures at the same time as it is placed. Furthermore, rust does not occur on the water guide sheet, and the landscape is not impaired during the construction period.

  The water guide sheet is for collecting water on the outer periphery of the shotcrete and guiding the water to a predetermined place such as a drain pipe. Therefore, it is necessary to be a sheet body that absorbs water and includes a gap in which the absorbed water can move by gravity. Moreover, it is necessary to provide durability against concrete spraying, and as such a sheet body, for example, a nonwoven fabric having a single layer structure is suitable.

  The water guide sheet is provided with sufficient strength to withstand the spraying pressure of the shotcrete by being firmly fixed to the flange of the support work. However, in order to reliably prevent the sprayed concrete from leaking through the gap between the flange and the water guide sheet, the surface of the water guide sheet that closes the interval between the support works is directed to the outside of the constructed arch culvert. It is preferable to hold it with a wire rod stretched on. As the wire, for example, a known wire can be used. Moreover, a wire can be made into the state which hold | suppresses a water conveyance sheet | seat by arrange | positioning in the circumferential direction of the water conveyance sheet | seat outer peripheral surface, and restraining the both ends in the tensioned state. As a restraining method, for example, an anchoring bolt and an L-shaped steel material installed in advance in the lower half of the existing spraying (both sides) may be used. The number of wires may be determined according to the construction situation, but it is preferable to arrange the wires so that the distance between the wires is about 20 cm. Furthermore, when arrange | positioning two or more wires, the pressing effect with respect to a water conveyance sheet | seat can be heightened more by attaching a net | network etc. between each wire. In addition, since the wire is not so heavy, it is not necessary to assemble an external scaffold for installation, and it is not necessary to use a crane or the like. It can be easily installed even on aerial work platforms.

It is a perspective view which expands and shows the construction structure of the arch culvert concerning this invention. It is a perspective view which shows the general appearance of the structure for construction. It is a sectional side view which shows an example of the fixing structure of the water guide sheet | seat and the net | network in the structure for construction. It is a front sectional view of an arch culvert constructed by adopting the construction structure. It is a perspective view which shows the external appearance of other embodiment of the construction structure of the arch culvert concerning this invention. The test apparatus of the structure for construction of the arch culvert concerning the present invention is shown, (a) is a front view and (b) is a side view. It is a sectional side view which shows the fixing structure of the water guide sheet | seat and the net | network in the Example for a test. It is a sectional side view which shows the fixing structure of the water guide sheet and the net | network in the comparative example for a test.

  With reference to FIGS. 1-4, the Example of the construction method of the arch culvert concerning this invention is described. In addition, in FIGS. 1-4, a part of site | part is emphasized and shown for convenience for making an understanding of a construction method easy, and the relative relationship of the magnitude | size of each site | part is not exact.

  In the construction of the arch culvert 10, in this construction method, first, a plurality of supporters 1 having an H-shaped cross section are installed at intervals. At this time, the flanges 1 a and 1 b of each support work 1 are arranged in a direction parallel to the mine shaft 11 of the arch culvert 10 to be constructed. In FIG. 2, three support works 1 are installed on the web 1 c of the support work 1, but the number thereof is not limited, and may be adjusted according to the length of the arch culvert 10 to be constructed. Moreover, the space | interval which installs the support work 1 is adjusted according to durability of the water guide sheet 2 mentioned later.

  Then, the flange 1a arrange | positioned the water guide sheet 2 and the net | network 3 which covers the surface facing the inner side of the arch culvert 10 where the water guide sheet 2 is constructed from the outside of the arch culvert 10 where the water guide sheet 2 is constructed. It is tensioned in a state where it is in contact with the inner surface, and the interval between the support works 1 is closed to obtain the state shown in FIGS. The structure in the state shown in FIGS. 1 and 2 corresponds to the arch culvert construction structure according to the present invention.

  In this construction structure, the water guide sheet 2 preferably absorbs water and has a gap inside which the absorbed water can move by gravity, and a single-layer nonwoven fabric is preferable. The net 3 may be anything that prevents and separates the water guide sheet 2 from the shotcrete 7, but a so-called welded wire net is suitable.

  There is no restriction on the method for stretching the water guide sheet 2 and the net 3, and it is sufficient to fix their edges to the support 1 by a known method. However, the two supports 1 are welded to both webs 1c of the adjacent support 1 A method of using the bar 5 spanned over the work 1 is preferable. In this case, as shown in FIG. 3, the water guide sheet 2 and the net 3 are tightly wound around the outside of the bar 5 using the wire 6 in a state where the bar 5 is sandwiched, so that the bar 5 is wrapped around. Fixed. The wire 6 is not limited as long as it can be sewn to the water guide sheet 2 and has a rigidity sufficient to withstand the spraying work of the shotcrete 7 described later, and a known wire (so-called wire) is used. May be.

  If it is the said structure for construction, next, the spraying work of the shotcrete 7 will be performed. In this spraying work, the shotcrete 7 tends to generate gaps in the vicinity of the flanges 1a, 1b and the web 1c of the support 1, and when the work starts from the vicinity of the center between the supports 1, the attached concrete There is a possibility that the water guide sheet 2 may hang down with a weight of 7. Therefore, in order to prevent the water guide sheet 2 from drooping due to the weight of the concrete 7 and to alert the user that the air gap is likely to occur, first, a part where the water guide sheet 2 and the net 3 overlap the flange 1a. Spray spray concrete 7 onto Then, spray concrete 7 is sprayed over the net 3 against the water guide sheet 2.

  What is necessary is just to perform the said spraying operation | work using a well-known spraying machine. However, when spraying the water guide sheet 2 through the net 3, the spray method in which the tip of the nozzle of the sprayer is swung may cause the water guide sheet 2 to jump and the wire 6 to be cut. Therefore, spraying is performed by a method in which the water guide sheet 2 and the net 3 are built up on the concrete 7 sprayed on the portion overlapping the flange 1a. According to this method, the jump of the water guide sheet 2 can be reduced and the wire 6 can be prevented from being cut.

  When the spraying operation is completed and the shotcrete 7 is solidified, the lining concrete 8 and the roadbed 9 can be placed by a known method. In addition, in FIG. 4, although the invert concrete 12 which comprises the lower layer of the lining concrete 8 is driven after installation of the said supporting work 1, since the construction method is well-known, description is abbreviate | omitted.

  In the arch culvert 10 constructed by adopting this construction method, the water guide sheet 2 is integrated without being separated from the shotcrete 7 via the net 3. Then, on the outer periphery of the shotcrete 7, spring water and rain water from the natural ground are collected and guided to the foundation of the arch culvert 10. The water guided to the foundation part is collected in a drain pipe 14 embedded in the roadbed 9 via an external water collecting pipe 13, and a part of the side drain pipe 15 provided in the foundation part of the arch culvert 10. Collected and drained to a predetermined facility. In addition, what is necessary is just to provide the thing of the optimal form for water collection facilities, such as the drain pipe 14, according to an installation condition.

  According to this construction method, the water guide sheet 2 functions as a surface corresponding to the sprayed surface of shotcrete formed with a steel corrugated plate or the like in the conventional construction method. And since this water conveyance sheet | seat 2 is lighter than a steel board | plate material, it can install easily in a construction site, without assembling an external scaffold and using a crane etc. Moreover, the shotcrete 7 is subjected to drainage measures by the water guide sheet 2 at the outer periphery thereof at the same time as the placing. Furthermore, rust does not occur in the water guide sheet 2 and the landscape is not impaired during the construction period.

  In this construction method, the water guide sheet 2 is sufficiently fixed to the flange 1a of the support 1 so as to have sufficient strength to withstand the spraying pressure of the shotcrete. However, in order to surely prevent the sprayed concrete from leaking out from the gap between the flange 1a and the water guide sheet 2, the water guide sheet 2 that closes the interval between the support works 1 is constructed before the sprayed concrete is sprayed. It is preferable to press the surface directed to the outside of the arch culvert 10 with a wire rod stretched in the circumferential direction. FIG. 5 shows a construction structure when the water guide sheet 2 is pressed with a wire. In FIG. 5, the same parts as those in the construction structure shown in FIGS.

  In the construction structure shown in FIG. 5, the surface of the water guide sheet 2 facing the outside of the constructed arch culvert 10 (hereinafter referred to as the outer peripheral surface) is pressed by the wire 4 stretched in the circumferential direction. Six known wires are used for the wire (hereinafter referred to as wires 4), and each wire 4 is attached to a plastic net that does not expand and contract. The six wires 4 integrated with the net-like net are arranged on the outer peripheral surface of the water guide sheet 2 in parallel at intervals of about 20 cm along the circumferential direction, and both ends thereof are restrained in a tensioned state. The sheet 2 is pressed. For the restraint of these wires 4, anchor fixing bolts and L-shaped steel materials (not shown) installed in advance on the lower half existing blowing (both sides) are used. In addition, since the wire is not so heavy, it is not necessary to assemble an external scaffold for installation, and it is not necessary to use a crane or the like. It can be easily installed even on aerial work platforms.

  In the construction structure shown in FIGS. 1 to 4 and FIG. 5, the interval between the pair of support works 1 is set as one construction section, and the spraying work is sequentially performed for each construction section. It is placed only in the construction section to be performed. And after the spraying operation in the construction section is completed, it is moved to the next section (the section on the opening side in FIG. 5) and arranged in the same manner.

As shown in FIG. 6, a water guide sheet 22 and a net 23 (not shown in FIG. 6) are stretched between two H-shaped steels 21 (corresponding to the support work of the present invention) fixed to the gantry 20. A spray test of shotcrete was conducted. The H-shaped steel 21 was installed in parallel with a web interval W of 1200 mm. In the gantry 20, the height h from the bottom surface 20a to the top surface 20b of the support member of the H-section steel 21 was 3150 mm, and the test section t was 4000 mm. Further, an H200 arch was used for the H-section steel 21. The spraying operation was performed using a wet sprayer. Shotcrete for spraying was produced using a batcher plant in the test site. The formulation and strength were as shown in Table 1.

"Example"
As shown in FIG. 7, the water guide sheet 22 was fixed by welding and fixing to the webs 21 c of the two H-shaped steels 21, and using a bar 25 that was bridged between the two H-shaped steels 21. Reinforcing bars D13 were used for the bars 25, and they were arranged at intervals of 425 mm in the length direction of the H-section steel 21. As the water guide sheet 22, a single-layer nonwoven fabric having a thickness of 5 mm was used. For the mesh 3, a welded wire mesh having a mesh size of 50 mm in length and width was used. Furthermore, a wire is used for the wire rod 26 used for fixing to the rod 25 and fixing the water guide sheet 22 and the net 23, and the binding for fixing the water guide sheet 22 and the net 23 is 213 mm × 250 mm. It was carried out at a rate of one place in the range (0.05325 m ² ).

"Comparative example"
On the other hand, as a comparative example, as shown in FIG. 8, the water guide sheet 22 was fixed to a web 21 c of two H-shaped steels 21 by welding, and a bar 25 spanned between both H-shaped steels 21 was used. About the case, the spraying operation | work similar to the said Example was performed. In this comparative example, the materials of the net 3, the bar 25, and the wire 26 are the same as those in the example. However, unlike the example, the water guide sheet 22 is a non-woven fabric having a two-layer structure with a thickness of 10 mm. Moreover, it was set as the fixed structure which the water guide sheet | seat 22 touches the back surface (equivalent to the outer surface of the flange arrange | positioned from the outside of the constructed arch culvert in this invention) of the flange 21b. Further, the bars 25 are also arranged at intervals of 950 mm in the length direction of the H-section steel 21, and the binding for fixing the water guide sheet 22 and the net 23 is 150 mm intervals on both sides in the vicinity of the H-section steel 21. Fixed with.

  As a result of the spray test, in the comparative example, the water discharge sheet fixing portion of 5 mm was torn at the center by the spray discharge force, and the spray was ejected from the gap (50 mm) between the flange 21a of the H-section steel 21 and the wire rod 26. Therefore, the spraying work could not be completed. On the other hand, in the Example, it was able to spray to the last, without the water conveyance sheet | seat 22 jumping up and ejecting outside. In addition, after the spraying work was completed, the water guide sheet 22 was peeled off and the filling condition of the shotcrete was confirmed, but the shotcrete was tightly packed in the space near the flange 21a, and there was no gap or nest. It was confirmed that there was no problem in adhesion between the attached concrete and the water guide sheet 22.

  During the operation of the example, the water guide sheet 22 was pushed upward by the discharge force of the spraying machine, and when the water guide sheet 22 was peeled off and confirmed after the spraying operation was completed, the sheets were bound. It was confirmed that the unexposed areas (free surfaces) swelled outside. Therefore, as a result of actually measuring the degree of swelling of the shotcrete to the outside of the H-shaped steel 21, it was confirmed that there was an average swelling of 2.2 cm. And it was confirmed from visual confirmation and a measurement result that 20 cm which is the required thickness of shotcrete is satisfied.

DESCRIPTION OF SYMBOLS 1 Supporting work 1a, 1b, 21a Flange 1c, 21c Web 2, 22 Water guide sheet 3, 23 Net 4, 6, 26 Wire material 5, 25 Bar material 7 Shotcrete 8 Covering concrete 9 Subbase 10 Arch culvert 11 Tunnel 12 Invert Concrete 13 Outside water collecting pipe 14 Drain pipe 15 Side drain pipe 20 Mounting base 20a Bottom 20b Top 21 H-section steel

Claims (6)

A plurality of support works with an H-shaped cross-section are installed at intervals, with the flanges parallel to the arch culvert tunnel constructed,
A state in which the water guide sheet and a net covering a surface of the water guide sheet facing the inside of the constructed arch culvert are in contact with the inner surface of the flange disposed outside the arch culvert to be constructed. Tighten with, close the interval of the support work,
An arch culvert construction method comprising spraying spray concrete over the net after spraying spray concrete onto a portion where the water guide sheet and the net overlap the flange.   The arch culvert construction method according to claim 1, wherein the water guide sheet is a non-woven fabric having a single layer structure.   Before spraying the shotcrete, the surface directed to the outside of the constructed arch culvert of the water guide sheet that closes the interval between the support works is pressed with a wire stretched in the circumferential direction. The construction method of the described arch culvert. The cross-sectional shape is composed of an H-shaped support, a water guide sheet, and a net covering the surface directed to the inside of the arch culvert on which the water guide sheet is constructed,
The support is installed in a direction in which the flange is parallel to the constructed arch culvert tunnel, and a plurality of them are installed at intervals.
The water guide sheet and the net are stretched in a state in which the water guide sheet is in contact with the inner surface of the flange disposed from outside the constructed arch culvert, and closes the interval between the support works. Arch culvert construction structure.   The arch culvert construction structure according to claim 4, wherein the water guide sheet is a single-layered nonwoven fabric. The construction structure for an arch culvert according to claim 4 or 5, wherein a surface of the water guide sheet directed to the outside of the constructed arch culvert is pressed by a wire stretched in a circumferential direction.

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