JP7123335B2 - Construction method of water stop structure of concrete joint - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for constructing a water stop structure for concrete joints.

BACKGROUND ART There are various forms of concrete structures in which secondary concrete having concrete joints is formed on the surface of primary concrete. For example, in a form where the slab (bottom slab, floor of each floor, ceiling, etc.) or wall of the permanent underground concrete structure is connected to the surface of an earth retaining wall such as a diaphragm wall, a diaphragm wall, etc. The earth retaining wall of the main building is primary concrete, and the walls and slabs of the permanent underground concrete structure are secondary concrete. In this form, for example, there can be concrete joints between slabs and walls, and concrete joints between walls. Also, in tunnels such as mountain tunnels, the shotcrete that is constructed so as to involve the steel shoring becomes the primary concrete, and the secondary lining that is constructed inside the primary concrete becomes the secondary concrete. . In this secondary lining, concrete joints can be present at predetermined intervals in the axial direction of the tunnel.
A water stop plate is sometimes installed in the water stop structure of the concrete joint. It is common for the water plate to be temporarily fixed. After temporarily fixing the water stop plate to the gable frame, pre-cast concrete is placed, part of the water stop plate is buried in the pre-cast concrete, and the water stop projecting from the end face of the gable side of the pre-cast concrete. A water cut-off structure of the concrete joint is formed by constructing the plate so that the post-cast concrete is involved. In construction to temporarily fix the water stop plate to the gable frame in this way, it is necessary to process the gable frame in such a way that the water stop plate is temporarily fixed to the gable frame. As a result, the construction of temporarily fixing the water stop plate to the end frame can be a factor that prolongs the construction period. In particular, in the construction of the mountain tunnel described above, this problem becomes more pronounced as the tunnel length increases and the number of concrete joints increases.

Thus, regarding the method of temporarily fixing the water stop plate to the gable frame, an installation method has been proposed in which the water stop plate is installed at the concrete joint between the arch portion and the inverted portion of the tunnel lining concrete. In this waterstop installation method, the deformation of the waterstop plate on the arch side due to external stress such as flow pressure and buoyancy of the concrete when concrete is placed in the arch part is prevented by attaching it to the laid rootstock. The fixing hardware is prevented by the fixing hardware, and the fixing hardware is pulled out without deforming the water stop plate during concrete placement, and the extraction hole is closed by natural flow of concrete (see, for example, Patent Document 1).

JP-A-5-133199

In the method for installing a water stop plate described in Patent Document 1, a fixing metal fitting attached to a base for a fixed tree corresponding to a gable frame is installed, and the water stop plate is temporarily fixed with this fixing metal fitting. Therefore, it is difficult to solve the above problems that may occur when temporarily fixing the water stop plate to the end frame.
SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for constructing a water stop structure for concrete joints that eliminates the need to temporarily fix a water stop plate to a gable frame.

In order to achieve the above object, one aspect of the water stop structure for concrete joints according to the present invention includes:
A water stop structure for a concrete joint in a concrete structure in which secondary concrete having a concrete joint is formed on the surface of primary concrete,
a waterproof sheet attached to the surface of the primary concrete at a position corresponding to the concrete joint;
An edge cutting sheet attached to a position straddling the concrete joint portion on the surface of the water stop sheet and cutting an edge between the water stop sheet and the secondary concrete. do.

According to this aspect, since the waterproof sheet is directly or indirectly attached to the surface of the primary concrete, it becomes unnecessary to attach (temporarily fix) the waterproof sheet to the end frame. Since the edge cutting sheet is interposed between the water stop sheet and the concrete joint portion of the secondary concrete, the so-called zero span phenomenon in which the water stop sheet is restrained by the construction of the secondary concrete is less likely to occur. Damage to the waterproof sheet due to deformation of the concrete structure that may occur at the time of is eliminated.
In this aspect, the concrete structure having primary concrete and secondary concrete includes, as already described, an earth retaining wall such as a diaphragm wall that is primary concrete, and a permanent underground concrete that is secondary concrete. Examples include a concrete structure formed from a structure, and a tunnel such as a mountain tunnel composed of shotcrete, which is primary concrete, and secondary lining, which is secondary concrete.

The edge cutting sheet attached to the water stop sheet and interposed between the water stop sheet and the secondary concrete has, for example, a smooth surface facing the secondary concrete and a small coefficient of friction between it and the secondary concrete. Another example is to suppress the edge cutting sheet from being dragged by the deformation when the concrete is deformed next time. Another example is a form in which the edge-cutting sheet has a deformability, so that when the secondary concrete is deformed, the edge-cutting sheet follows the deformation or absorbs the deformation. Furthermore, a form having both of these performances is included. In any form, by having such performance, it literally becomes a "edge cutting sheet" between the water stop sheet and the secondary concrete, and the water stop sheet is not affected by the deformation of the secondary concrete. Alternatively, it is possible to reduce the influence as much as possible, and to eliminate breakage of the waterproof sheet caused by the zero span phenomenon.

In another aspect of the water stop structure for concrete joints according to the present invention, the water stop sheet is adhered to the surface of a base material to form a water stop plate, and the base material is attached to the surface of the primary concrete. It is characterized by being
According to this aspect, since the water stop sheet is adhered to the surface of the base material to form the water stop plate, the base material can be directly attached to the surface of the primary concrete, and the water stop sheet can be directly attached. It is possible to solve problems such as breakage of the waterproof sheet that may occur at times. Here, as the base material forming the water stop plate, a resin base material having a certain hardness can be applied. In addition, when a water stop plate is applied to the inner space of a tunnel, the water stop sheet has sufficient deformation performance, so it is possible to bend it according to the predetermined curvature of the tunnel. It is preferable to apply a base material made of resin having deformability. Here, as a method for attaching (the base material of) the water stop plate to the primary concrete, there are a method by adhesion, a method by using nails or rivets, and a method combining these methods.

Further, in another aspect of the water stop structure for concrete joints according to the present invention, a waterproof sheet is attached to the surface of the primary concrete, and the water stop sheet is attached to the surface of the waterproof sheet. Characterized by
According to this aspect, the waterproof sheet is attached to the surface of the primary concrete, and the waterproof sheet is attached to the surface of the waterproof sheet. As compared with the case where the waterproof sheet is directly attached to the concrete, the attachment of the waterproof sheet is improved.

In another aspect of the water stop structure for a concrete joint according to the present invention, the water stop sheet is adhered to the mounting surface.
According to this aspect, since the waterproof sheet is attached by adhesion, it is of course unnecessary to temporarily fix the waterproof sheet to the end frame, and the waterproof sheet can be attached to the mounting surface. can be easily done. Here, the "mounting surface" is the surface of the primary concrete when the waterproof sheet is directly mounted on the surface of the primary concrete. On the other hand, when the waterproof sheet is attached to the surface of the primary concrete, the surface of the waterproof sheet becomes the mounting surface.

In another aspect of the water stop structure for a concrete joint according to the present invention, the edge cutting sheet is adhered to the water stop sheet.
According to this aspect, since the edge cutting sheet is adhered to the water stopping sheet, it is possible to easily manufacture the water stopping sheet provided with the edge cutting sheet. For example, by adhering the adhesive surface of an edge cutting sheet made of Sellotape (registered trademark) or the like to a resin waterproof sheet, the edge cutting sheet can be easily attached to the water shutoff sheet, and the smoothness of the Sellotape can be improved. The smooth surface and stretchability provide an excellent edge-cutting effect with the secondary concrete. Furthermore, by applying cellophane tape or the like to the edge cutting sheet, the production cost of the waterproof sheet having the edge cutting sheet on its surface can be reduced as much as possible.

In addition, one aspect of the method for constructing a water stop structure for concrete joints according to the present invention is as follows:
A method for stopping water at a concrete joint in a concrete structure in which secondary concrete having a concrete joint is formed on the surface of primary concrete, comprising:
a waterproof sheet attaching step of attaching a waterproof sheet to a position corresponding to the concrete joint portion on the surface of the primary concrete;
A precast concrete for the secondary concrete is constructed so as to involve a part of the water stop sheet, and then a part of the water stop sheet overhanging from the concrete joint is rolled in to the secondary concrete. and a secondary concrete construction step of constructing the post-cast concrete of
In the step of attaching the water stop sheet, an edge cutting sheet is attached to cut the edge between the water stop sheet and the secondary concrete on the surface of the water stop sheet at a position straddling the concrete joint. It is characterized by

According to this aspect, it is possible to directly or indirectly attach the waterproof sheet to the surface of the primary concrete while making it unnecessary to attach (temporarily fix) the waterproof sheet to the gable frame (when the waterproof sheet is present is indirect attachment to the primary concrete), the water stop structure can be efficiently constructed, and the problem of the lengthening of the construction period due to the construction of the water stop structure is less likely to occur.

According to the method for constructing a water stop structure for a concrete joint of the present invention, in a concrete structure in which a secondary concrete having a concrete joint is formed on the surface of a primary concrete, a water stop plate for the end frame is provided. It is possible to eliminate the need for temporary fixing of the water stop structure and efficiently construct a water stop structure. Furthermore, it is possible to eliminate the breakage of the waterproof sheet due to the deformation of the secondary concrete at the joint of the secondary concrete.

It is process drawing which shows an example of the construction method of the water stop structure of the concrete joint part which concerns on embodiment. (a), (b), and (c) are all perspective views showing an embodiment of a unit of a water stop sheet and an edge cutting sheet forming a water stop structure. 1. It is process drawing which shows an example of the construction method of a water stop structure following FIG. FIG. 4 is a process chart showing an example of a method for constructing a water stop structure subsequent to FIG. 3 ; FIG. 5 is a process chart showing an example of a method for constructing a water stop structure subsequent to FIG. 4 ; It is a cross-sectional view which shows an example of the water stop structure of the concrete joint part which concerns on embodiment. 1 is a diagram showing a test piece 1 according to an example used in a performance confirmation test, (a) is a longitudinal sectional view of the test piece 1, and (b) is a secondary concrete when viewed from above the test piece 1 1 is a perspective plan view of FIG. FIG. 2 is a diagram showing a test piece 2 according to a comparative example used in a performance confirmation test, where (a) is a longitudinal sectional view of the test piece 2, and (b) is a secondary concrete when viewed from above the test piece 2 1 is a perspective plan view of FIG.

Hereinafter, a waterproof structure for a concrete joint and a construction method thereof according to the embodiment will be described with reference to the accompanying drawings. In this specification and drawings, substantially the same components may be denoted by the same reference numerals, thereby omitting duplicate descriptions.

[Water stop structure of concrete joint according to embodiment and its construction method]
An example of a waterproof structure for a concrete joint according to an embodiment and a construction method thereof will be described with reference to FIGS. 1 to 6. FIG. Here, FIGS. 1 and 3 to 5 are process diagrams showing the construction method of the water stop structure of the concrete joint portion according to the embodiment. FIG. 2 is a perspective view showing an embodiment of a unit of a water stop sheet and an edge cutting sheet forming a water stop structure, and FIG. 6 shows an example of the water stop structure of a concrete joint portion according to the embodiment. It is a cross-sectional view. A mountain tunnel will be described below as a concrete structure formed from primary concrete and secondary concrete.

As shown in FIG. 1, a tunnel T having a predetermined dimension and a predetermined cross-sectional shape is created by drilling a ground G. As shown in FIG. Here, the ground ground G may be drilled by a tunnel boring machine, or by digging a hole in the face surface with a machine such as a jumbo, charging it with dynamite and blowing it up. good. After drilling a hole with a predetermined length, steel arch supports (not shown) are installed at predetermined intervals to protect the wall of the hole. After that, the primary concrete 10 (shotcrete) having a predetermined thickness (for example, about 5 cm to 25 cm) is constructed by spraying concrete so as to involve the shoring. The construction of the primary concrete 10 is carried out by carrying a concrete mixer truck into the tunnel T and spraying concrete onto the wall of the hole with a sprayer. At the time of construction of the primary concrete 10, a wire mesh is attached to the natural ground G side, and the shotcrete is applied to the natural ground G having the wire mesh on the surface thereof. It can also adhere well.

After the concrete is sprayed, the rock bolts 11 are installed. The rock bolt 11 is made of, for example, a bar-shaped steel material with a length of about 3 m to 4 m. . The lock bolt 11 may be installed radially in a plane perpendicular to the axial direction of the tunnel T, or may be installed obliquely in the drilling direction of the tunnel T. As shown in FIG. The latter installation of the tunnel T in the drilling direction is a pre-receiving work, and as this pre-receiving work, instead of the rock bolts 11, for example, a long steel pipe of 10 m or more may be applied. More specifically, an injection-type long pre-receiving method can be applied, in which a small-diameter steel pipe with a predetermined outer diameter is inserted while drilling the ground with a special bit, and the injection material is injected into the steel pipe at a predetermined pressure. It is a method of building pre-emptive work. In this way, after excavating the natural ground, the shotcrete 10 is applied and the rock bolts 11 are applied, thereby suppressing loosening of the natural ground G and constructing the tunnel T. NATM (New Austrian Tunneling Method) ) applies.

By repeating the work from drilling the ground G to installing the rock bolts 11 a predetermined number of times, after constructing a tunnel T of a predetermined length reinforced by the primary concrete 10 and the rock bolts 11, the inner side of the primary concrete 10 is constructed. A waterproofing work is performed to lay a waterproof sheet 20 on the ground. As the waterproof sheet 20, a waterproof sheet such as EVA resin (EVA: ethylene-vinylacetate copolymer, ethylene-vinyl acetate copolymer) having excellent chemical resistance and impact resistance can be applied. Further, a back cushioning material made of non-woven fabric or the like with drainage properties may be disposed on the back side of the EVA resin (on the side of the primary concrete 10). The above is the waterproof sheet installation process including the installation of the waterproof sheet in the construction method for the waterproof structure of the concrete joint.

Next, when constructing the secondary lining made of secondary concrete for each predetermined length, a waterproof sheet is installed at the concrete joint portion between the adjacent secondary linings. Here, various types of waterproof sheets will be described with reference to FIG. In addition, FIG. 2 shows a state in which the originally long waterproof sheet is cut in the middle. In the water stop structure of the concrete joint according to the present embodiment, an edge cutting sheet that cuts the edge between the water stop sheet and the secondary concrete is attached on the surface of the water stop sheet. It has a unit configuration of a waterproof sheet and an edge cutting sheet as a basic configuration.

The form shown in FIG. 2( a ) has a waterproof sheet 30 and an edge cutting sheet 40 adhered to the surface of the waterproof sheet 30 . As the waterproof sheet 30, a non-vulcanized adhesive plastic body using recycled butyl rubber can be applied, and more specifically, Spanseal (registered trademark) manufactured by Hayakawa Rubber Co., Ltd. can be applied. This span seal is a product that integrates with concrete and stops water by chemically bonding through an ionic reaction between the metal oxide (CaO) contained in the cement and the active group (carboxyl group) of the span seal. is. As the edge cutting sheet 40, a sheet made of sellotape (registered trademark) or the like and having a back surface serving as an adhesive surface is applied. Cellophane tape is a band-shaped tape in which one side of cellophane (base material) made of wood pulp is coated with an adhesive mainly composed of natural rubber and natural resin.

The edge-cutting sheet 40 has, for example, a smooth surface facing the secondary concrete and a small coefficient of friction with the secondary concrete. Therefore, when the secondary concrete is deformed, the edge-cutting sheet 40 is suppressed from being dragged by the deformation. It works. Alternatively, the edge-cutting sheet 40 has a deformability, so that when the secondary concrete is deformed, the edge-cutting sheet 40 follows the deformation or absorbs the deformation. The edge cutting sheet 40 having such performance literally cuts the edge between the water stop sheet 30 and the secondary concrete. It has the effect of preventing the waterproof sheet 30 from being affected. The waterproof sheet 30 can be attached to the surface of the waterproof sheet 20 shown in FIG. .

On the other hand, in the form shown in FIG. 2( b ), the water stop sheet 30 is adhered to the base material 50 to form the water stop plate 60 , and the water stop plate 60 and the edge cutting sheet 40 are provided. As the base material 50, a base material made of EVA resin is applied. When the base material 50 is made of EVA resin, the base material 50 has good deformability, and the base material 50 can be easily deformed in the circumferential direction of the tunnel T while the base material 50 is applied to the surface of the curved waterproof sheet 20 . 50 can be installed. Since the water stop plate 60 having the base material 50 is provided, when the water stop plate 60 is attached to the waterproof sheet 20 and the primary concrete 10 with nails or the like, the nails are not driven directly into the water stop sheet 30. , breakage of the waterproof sheet 30 due to hammering of nails can be eliminated.

On the other hand, the form shown in FIG. 2(c) is composed of a base material 50A having a nailing portion 50a having a nailing groove 50b, a water stop plate 60A formed of a water stop sheet 30, and an edge cutting sheet 40. be done. Although nails may be driven into the surface of the base material 50A other than the nailing grooves 50b of the nailing part 50a, since the substrate 50A has the nailing parts 50a, the primary concrete 10 on the back surface of the waterproof sheet 20 is Attachability with a nail to the In addition, since the base material 50A has a nailing groove 50b having a substantially V-shaped cross section as shown in the drawing, the water cutoff sheet 30 can be used when the secondary concrete is placed in a post-process and the formwork is demolded. peeling off can be prevented.

Hereinafter, a water stop structure for concrete joints and a construction method thereof will be described using the unit of the water stop plate 60 and the edge cutting sheet 40 shown in FIG. 2(b). In the following description, illustration and description of the inverted concrete that is constructed prior to the construction of the secondary concrete that is the secondary lining will be omitted.

The secondary concrete, which is the secondary lining, is constructed at intervals of about 10 m in the axial direction of the tunnel T, for example. When constructing the secondary concrete, as shown in FIG. 3, a unit of a water stop plate 60 and an edge cutting sheet 40 is attached in the circumferential direction of the tunnel T at a position to be a concrete joint. The water stop plate 60 may be attached to the waterproof sheet 20 (and the primary concrete 10) by an adhesive method, a nailing method, or a combination thereof. In FIG. 3, the edge cutting sheet 40 is arranged so as to face the inner side of the tunnel T, and the edge cutting sheet 40 is placed at the center position of the concrete joint, that is, at the position straddling the pre-cast concrete and the post-cast concrete of the secondary concrete. is arranged. Here, the installation of the water stop plate 60 and the edge cutting sheet 40 unit may be performed prior to the construction of the secondary lining, for example, every 10 m, which will be the concrete joint portion, or the water stop plate The installation of the unit of 60 and edge cutting sheet 40 and the installation of the secondary lining may be alternately performed. For example, prior to the construction of the secondary lining, the units are installed prior to each concrete joint. The construction method of placing concrete can be applied. In addition, in each figure after FIG. 3, illustration of bar arrangement is abbreviate|omitted.

After attaching the water stop plate 60 and edge cutting sheet 40 unit to the surface of the waterproof sheet 20, as shown in FIG. do. As shown in FIG. 4, the pre-cast concrete 70A is constructed so as to involve not only part of the waterproof sheet 30 but also part of the edge cutting sheet 40 on the surface of the waterproof sheet 30 .

Next, as shown in FIG. 5, by constructing post-cast concrete 70B continuing to pre-cast concrete 70A, secondary concrete 70, which is a secondary lining, is constructed via concrete joint CJ. The thickness of the secondary concrete 70, which is the secondary lining, may be about the same as the thickness of the primary concrete 10, or may have a thickness of about 1 m as a secondary lining having greater earthquake resistance. . A concrete structure comprising a primary concrete 10 formed of shotcrete by construction of the secondary concrete 70, a waterproof sheet 20, and a secondary concrete 70 as a secondary lining having a concrete joint CJ. A body 80 is constructed. The above is the secondary concrete construction process in the construction method of the water stop structure of the concrete joint. The tunnel T has concrete joints CJ at predetermined intervals in its axial direction, and secondary concrete 70 consisting of pre-placed concrete 70A and post-placed concrete 70B on the left and right of the concrete joints CJ.

According to the method for constructing a waterproof structure for a concrete joint described above, the edge cutting sheet 40 is placed on the surface of the primary concrete 10 and the waterproof sheet 20 at a position where the concrete joint of the secondary concrete 70 will be formed. After that, pre-cast concrete 70A and post-cast concrete 70B are successively constructed on the left and right sides of the edge cutting sheet 40 to construct the secondary concrete 70. - 特許庁Therefore, when the precast concrete 70A is constructed, it is possible to completely eliminate the time-consuming work of temporarily fixing the water stop sheet to the end frame at the position corresponding to the concrete joint. good workability is obtained. Therefore, as the length of the tunnel T increases and the number of concrete joints increases, this effect becomes even more pronounced.

A water stop structure 100 for a concrete joint shown as an example in FIG. As shown in FIG. 6, the water stop structure 100 includes a water stop plate 60 attached to the surface of the waterproof sheet 20 by adhesion, for example, and an edge cut sheet attached to the surface of the water stop sheet 30 by adhesion. 40, and the edge cutting sheet 40 is disposed across the pre-cast concrete 70A and the post-cast concrete 70B.

The surface of the waterproof sheet 20, which is in close contact with the primary concrete 10, has a lot of unevenness. It is brought into close contact with the surface of the waterproof sheet 20 so as to be familiar with it. When the waterproof sheet 30 is formed from the above-described span seal, the metal oxide ions in the cement forming the secondary concrete and the carboxyl groups of the span seal chemically react with each other to chemically bond and integrate with the concrete. A water-blocking structure 100 is formed.

Here, as is clear from FIG. 6, the water stop sheet 30 is constrained by the secondary concrete 70 due to the construction of the secondary concrete 70, and there is a margin (play) in both the axial direction and the axial direction of the tunnel. ), a so-called zero-span phenomenon occurs. When the water stop sheet 30 has the zero-span phenomenon, if the tunnel T is elongated in the axial direction or sheared in the direction perpendicular to the axis due to an earthquake or the like, these deformations of the tunnel T are caused. As a result, the waterproof sheet 30 may be damaged. However, according to the water stop structure 100 for concrete joints shown in the figure, the edges of the water stop sheet 30 and the secondary concrete 70 are cut by the edge cutting sheet 40 at the concrete joint CJ, so that the tunnel T The effect of deformation is absorbed or mitigated by the edge cutting sheet 40 . Therefore, breakage of the waterproof sheet 30 due to deformation of the concrete structure is effectively eliminated.

[Performance confirmation test and its results]
<Overview of performance confirmation test>
Next, a performance verification test and the results of the water stop structure of the concrete joint portion according to the embodiment conducted by the present inventors will be described with reference to FIGS. 7 and 8. FIG. Here, FIGS. 7 and 8 are diagrams showing the test body 1 according to the example and the test body 2 according to the comparative example used in the performance confirmation test, respectively. ) are vertical cross-sectional views of the specimen 1 and the specimen 2, respectively, and FIGS. It is a top view.

As shown in Figures 7 and 8, both test specimens 1 and 2 were made by bonding a cylindrical waterproof sheet to the surface of a cylindrical base material, straddling the primary concrete and the secondary concrete. is buried. In test sample 1, a cylindrical edge-cutting sheet was adhered to the surface of the waterproof sheet, and test sample 2 did not have this edge-cutting sheet. Inside the cylindrical base material, the edge cutting sheet and the cushioning material are arranged in order from the bottom at the joint between the primary concrete and the secondary concrete. A supply pipe to which pressurized water is supplied is arranged so that the tip thereof abuts against the cushioning material, and the supply port of the pressurized water of the supply pipe is provided outside the upper end of the secondary concrete. Furthermore, the supply pipe is equipped with a pressure gauge so that the water pressure of the pressurized water can be measured.

Low-heat Portland cement was applied to the cement in the concrete mix, and high-early-strength concrete was applied. As shown in Table 1 below, the performance test was carried out based on roughly three types of conditions and three levels of target performance.

(About Test I)
As shown in FIGS. 7 and 8, pressurized water is supplied in the X1 direction to the interface between the primary concrete and the secondary concrete through the supply pipe, and the pressurized water is permeated in the X2 direction to the waterproof sheet side through the cushioning material. , it was verified whether or not pressurized water leaked to the outside through the cylindrical waterproof sheet. Here, the water pressure was increased to the target water pressure at intervals of 0.10 MPa, and the water stoppage at the waterstop plate and the interface between the primary concrete and the secondary concrete was confirmed with a Bourdon tube type pressure gauge. Each water pressure stage was set for about 1 minute, and if there were no abnormalities, the next water pressure stage was assumed.

(About Test II)
Water pressure is applied to test specimens 1 and 2 at a pitch of 0.10 MPa to the target water pressure, and the water stoppage at the interface between the waterstop plate and the primary concrete - secondary concrete is confirmed with a Bourdon tube pressure gauge. did. However, after setting each water pressure, it was held for 5 minutes, and the change in water pressure was measured at intervals of 1 minute. At that time, the presence or absence of water leakage was also visually confirmed.

(About Test III)
After forcibly deforming the upper layers of the specimens 1 and 2 to the target amount of shear deformation with a hydraulic jack (in the direction of the arrows in FIGS. 7 and 8), the thickness is adjusted to the gap between the upper receiving steel material and the specimens 1 and 2. set the plate. The water pressure was increased to the target water pressure at intervals of 0.10 MPa, and the water stoppage at the water stop plate and the interface between the primary concrete and the secondary concrete was confirmed with a Bourdon tube type pressure gauge. However, after setting each water pressure, it was held for 5 minutes, and the change in water pressure was measured at intervals of 1 minute. At that time, the presence or absence of water leakage is also visually confirmed.

(Regarding the test cycle)
In Test II (elongation) and Test III (shear), separate specimens were used for both test specimens 1 and 2, and performances 1 to 3 were confirmed after performing test I (normal condition). Specifically, if the test specimen type is X and the order is "test (name of test specimen) - (type of test) - (target performance)", the test will be conducted in the following test cycle. did.
Test X1-I-1 → Test X1-II-1 → Test X1-II-2 → Test X1-II-3
Test X2-I-1 → Test X2-III-1 → Test X2-III-2 → Test X2-III-3
Between tests with different target deformation amounts, the water pressure was reloaded after adjusting the deformation amount by unloading the water pressure.

<Performance test results>
The test results are shown in Table 2 below. In Table 2, the case where each target performance is satisfied is indicated by ◯, and the case where it is not satisfied is indicated by x.

First, in the normal state in the elongation test of the comparative example (specimen 2), there was no water leakage or pressure gauge drop, and no abnormality was observed. Furthermore, in the elongation test, no abnormalities were observed up to the target performance 1 (deformation amount 10 mm, water pressure 0.25 MPa), but when a water pressure of 0.45 MPa was applied, water leaked from the boundary between the primary concrete and the secondary concrete. started and the pressure began to drop, so the test was terminated.
In addition, in the shear test of the comparative example (specimen 2), no abnormality was observed, such as no water leakage or lowering of the pressure gauge. Furthermore, in the shear test, water leakage started at the stage of shear deformation with a hydraulic jack (water pressure value: 0.08 MPa), so the test was terminated.

From the above results, it is determined that the specimen 2 according to the comparative example has water pressure resistance up to 0.40 Ma for a tensile deformation of 10 mm, but does not have water pressure resistance for a shear deformation of 10 mm. be done.

On the other hand, in the normal state in the elongation test of Example (specimen 1), there was no water leakage or pressure gauge drop, and no abnormality was observed. Furthermore, in the elongation test, no abnormalities were observed up to target performance 3 (deformation amount of 10 mm, water pressure of 0.60 MPa), and all three target performance levels were satisfied.
In addition, in the shear test of Example (specimen 1) under normal conditions, there was no water leakage or pressure gauge drop, and no abnormality was observed. Furthermore, in the shear test, no abnormalities were observed up to target performance 3 (deformation amount of 10 mm, water pressure of 0.60 MPa), and all three target performance levels were satisfied. After that, when a water pressure load of 0.70 MPa was applied, water leakage started from the boundary of the concrete, so the test was terminated.

From the above results, it is determined that the specimen 1 according to the example has a water pressure resistance performance of 0.60 MPa or more with respect to a tensile deformation amount and a shear deformation amount of 10 mm.

It should be noted that other embodiments may be possible in which other components are combined with the configurations listed in the above embodiments, and the present invention is not limited to the configurations shown here. . Regarding this point, it is possible to change without departing from the gist of the present invention, and it can be determined appropriately according to the application form.

For example, although the waterproof sheet 20 is a constituent element in the water stopping structure 100 of the concrete joint of the illustrated example, a water stopping structure without the waterproof sheet 20 may be used. In addition, although the water stop structure 100 of the concrete joint portion of the illustrated example is intended for mountain tunnels, other than mountain tunnels, earth retaining walls such as underground continuous walls made of primary concrete and secondary concrete The water stop structure of the concrete joint portion according to the embodiment may be applied to a concrete structure or the like formed from a permanent underground concrete structure.

10: Primary concrete (shot concrete), 11: Rock bolt, 20: Waterproof sheet, 30: Waterproof sheet, 40: Edge cutting sheet, 50, 50A: Base material, 60, 60A: Waterproof plate, 70: Secondary Concrete, 70A: Pre-cast concrete, 70B: Post-cast concrete, 80: Concrete structure, 100: Water stop structure of concrete joint (water stop structure), G: Ground, CJ: Concrete joint, T: tunnel

Claims (5)

A method for constructing a water stop structure for a concrete joint in a concrete structure in which secondary concrete having a concrete joint is formed on the surface of primary concrete, comprising:
a waterproof sheet attaching step of attaching a waterproof sheet to a position corresponding to the concrete joint on the surface of the primary concrete;
A precast concrete for the secondary concrete is constructed so as to involve a part of the water stop sheet, and then a part of the water stop sheet overhanging from the concrete joint is rolled in to the secondary concrete. and a secondary concrete construction step of constructing the post-cast concrete of
In the step of attaching the water stop sheet, on the surface of the water stop sheet, an edge cutting sheet for cutting the edge between the water stop sheet and the secondary concrete is adhered at a position straddling the concrete joint, A method for constructing a water stop structure for concrete joints, comprising: prefabricating a unit comprising the water stop sheet and the edge cutting sheet; and mounting the unit . 2. The concrete joint according to claim 1, wherein the water stop sheet is adhered to the surface of the base material to form a water stop plate, and the base material is attached to the surface of the primary concrete. Construction method of water stop structure. 3. The water stop structure for a concrete joint according to claim 1 or 2, wherein the edge cutting sheet is made of Sellotape (registered trademark), and the adhesion surface of the sellotape is adhered to the surface of the water stop sheet. Construction method. The secondary concrete is a secondary lining of a tunnel, and the concrete joint is a concrete joint of the secondary lining ,
Prior to the secondary concrete construction step, the waterproof sheet installation step is performed, and the unit is attached to a plurality of the concrete joints prior to the secondary lining construction. A method for constructing a water stop structure for a concrete joint according to any one of claims 1 to 3 . The secondary concrete is a secondary lining of a tunnel, and the concrete joint is a concrete joint of the secondary lining ,
The step of installing the waterproof sheet and the step of constructing the secondary concrete are set steps, and the setting step is performed for each corresponding region of the plurality of concrete joints, and the setting step is performed sequentially in the axial direction of the tunnel. A method for constructing a water stop structure for a concrete joint according to any one of claims 1 to 3 .

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