JP2015151755A - Sheath pipe structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheath pipe structure that can ensure strength of a dike and a bridge pier over a long period of time by stably maintaining a joint gap over the long period of time.SOLUTION: A sheath pipe structure comprises: a levee body T that constitutes a dike; a concrete bridge pier B that is erected within the levee body T; a sheath pipe 1 that is a concrete product provided in an annular shape in a plan view via a joint gap S being a space with predetermined dimensions in the plan view on the periphery of the bridge pier B; and a sediment inflow prevention part that makes a section between the sheath pipe 1 and the bridge pier B sealed with a highly-elastic adhesive with an elongation capability of 100-250%, at an upper edge of the joint gap S.

Description

  The present invention relates to a sheath pipe structure in which a sheath pipe is provided so as to form a gap between a bank body constituting a bank and a bridge pier standing in the bank body.

  When constructing a bridge in a river, the basic policy is not to install it in the levee body. This is because there is a tendency to create a gap between the levee body and the pier that make up the levee due to differences in normal traffic vibrations and vibration characteristics during earthquakes between the dyke and the pier, which can easily lead to water leakage and sediment loss. Because.

  However, depending on the width of the river and the size of the dike, the pier may be exceptionally provided with a pier. In that case, a so-called sheath tube structure in which a sheath tube for forming a gap is provided around the pier is applied. When a gap is provided around the bridge pier as in the configuration described in Patent Document 1, the gap absorbs the difference in vibration properties between the dam body and the bridge pier. This is because it can be suppressed.

  However, even when a sheath pipe structure is applied to the bridge pier, after construction, the sheath pipe is usually covered with earth and sand until the upper end is exposed to the ground surface. Due to the vibration of the time, earth and sand may flow in between play, and there may be a problem that the bridge pier and the sheath pipe interfere with each other through the flowing earth and sand. Therefore, conventionally, measures have been taken to prevent the inflow of earth and sand into the gap by providing a seal material at the upper end of the gap, but a gap is formed between the seal material and the sheath pipe or the pier with the passage of time due to vibration. Will be. Therefore, even if a sealing material is provided at the upper end of the play, it is the current situation that earth and sand also flows in from the gap after a certain period of time has elapsed after construction.

JP 2001-172914 A

  The present invention focuses on the current situation as described above, and an object of the present invention is to provide a sheath tube structure capable of stably maintaining a gap over a long period of time.

  In order to achieve such an object, the present invention takes the following measures.

  In other words, the sheath pipe structure according to the present invention has an annular shape in plan view through a bridge pier made of concrete standing in the levee body constituting the levee and a space that is a space having a predetermined size in plan view around the pier. A sheath pipe that is a concrete product provided, and a sediment inflow prevention portion that is sealed between the sheath pipe and the bridge pier at the upper edge between the play by a highly elastic adhesive having a capacity of 100% to 250%. It is characterized by comprising.

  If this is the case, the earth and sand inflow prevention part sealed with a high-elastic adhesive having an elongation capacity of 100% to 250% is highly elastic even if the size of the gap between the piers and the sheath pipe is changed due to vibration. By appropriately expanding and contracting the adhesive, it is possible to stably maintain a state where the upper end of the play is sealed. As a result, according to the present invention, it is possible to realize a sheath pipe structure capable of ensuring the strength of the embankment and the pier for a long period of time by stably maintaining a gap for a long period of time.

Moreover, in order to make it easy to finish the sediment inflow prevention part to a required shape without dripping the high elastic adhesive during construction, the density of the high elastic adhesive is 0.7 to 1.2 g / cm ³ . Preferably there is.

  And if the earth and sand inflow prevention part has a high elastic adhesive and an elastically deformable backup material that supports the high elastic adhesive from below, vibrations between the bridge pier and the sheath pipe are further reduced. Can be suppressed.

  In particular, if the backup material is made of a non-polar material to which the high-elastic adhesive cannot adhere, the high-elastic adhesive itself is not restrained by the backup material in addition to the vibration suppression by the backup material. Can fully exhibit the elongation ability.

  In addition, as a configuration for effectively mitigating the vibration that occurs in the sediment inflow prevention part by promoting absorption of vibration on the sheath tube side, it is integrated with the sheath tube between the sheath tube and the footing foundation constituting the levee body. A footing joint having an anchor bar protruding downward and a high elastic anchor portion covering the anchor bar made of a high elastic adhesive provided on the footing foundation. it can.

  As a specific configuration of the footing joint that can absorb vibrations suitably, an aspect having a mortar layer provided on the upper surface of the footing base and a buffering elastic material layer disposed on the upper surface side of the mortar layer is provided. Can be mentioned.

  When the sheath tube is composed of a plurality of sheath tube blocks connected in the vertical direction, the upper sheath tube block is integrally protruded downward as a configuration for effectively mitigating vibration applied to the sheath tube. And an anchor bar having a high-elasticity anchor portion covering the anchor bar made of a high-elasticity adhesive provided on the anchor bar and the lower sheath tube block. . In such a case, it is desirable that the vertical joint has a buffering elastic material layer interposed between the lower sheath tube block and the upper sheath tube block.

  And as another measure for suppressing the intrusion of earth and sand and water during play, the upper and lower joints do not face the play between the lower sheath tube block and the upper sheath tube block. The aspect which has the joint filling part which consists of a highly elastic adhesive with which the joint part formed in the outer surface side of a material layer was filled can be mentioned. In this case, if a backup material made of a non-polar substance to which the high-elasticity adhesive cannot adhere is interposed between the joint filling portion and the buffering elastic material layer, the high-elasticity adhesive itself can exhibit its elongation ability. Therefore, the watertightness between the sheath tube blocks can be effectively secured.

And as a highly elastic adhesive used for this invention, it is desirable also in terms of workability to apply the two-component adhesive of an epoxy resin and a modified silicone resin. In addition, if the high-elastic adhesive is an adhesive having a tensile strength of 0.2 N / mm ² or more when the concrete is bonded to each other, it absorbs vibrations applied to the sheath pipe even during earthquakes and is highly It is possible to effectively ensure the water tightness of the place where the elastic adhesive is used.

  ADVANTAGE OF THE INVENTION According to this invention, the sheath structure which can ensure the intensity | strength of a dike and a bridge pier for a long period of time can be provided by maintaining a gap freely over a long period of time.

The external view which concerns on one Embodiment of this invention. Structure explanatory drawing which concerns on the same embodiment. The plane sectional view of the sheath tube block concerning the embodiment. The longitudinal cross-sectional view of the principal part which concerns on the same embodiment. Structure explanatory drawing of the footing junction part which concerns on the same embodiment. Structure explanatory drawing of the same vertical direction junction. Structure explanatory drawing of the inflow prevention part. Action | operation explanatory drawing which concerns on the same embodiment.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  The sheath tube structure X according to the present embodiment is applied, for example, when the bridge pier B is provided in the levee body T constituting the levee for terrain or construction circumstances when a bridge is constructed in a river.

  As shown in FIGS. 1 to 4, such a sheath tube structure X has a bridge pier B made of concrete erected in the levee body T constituting the levee and a predetermined dimension in plan view around the pier B. It has a sheath tube 1 that is a concrete product provided in an annular shape in plan view through a space S that is a space. And the difference of the vibration property between the dam body T and the bridge pier B is made to absorb in the gap S, and it does not cause water leakage or runoff of earth and sand.

  Here, the sheath pipe structure X according to the present embodiment is a soil inflow sealed with a highly elastic adhesive 3a having an elongation capacity of 100% to 250% between the sheath pipe 1 and the pier B at the upper edge of the gap S. The prevention part 3 is provided. In addition, the sheath tube structure X according to the present embodiment uses an adhesive of the same type or the same type as that of the high-elasticity adhesive 3a as appropriate at the joint portion between the concrete, so that the dam body T and the pier B have different vibration properties. The transmission of vibration is suppressed.

  Hereinafter, the sheath tube structure X will be specifically described.

  The sheath tube structure X according to the present embodiment is based on the pier B standing on the footing foundation F provided in the levee body T constituting the levee among the plurality of piers B laid on the river. Applied. The pier B is mainly composed of concrete and has a structure in which reinforcing bars and the like are appropriately provided. However, since the concrete structure of the pier B can be applied to various existing structures, Detailed description is omitted.

  In this embodiment, the sheath pipe 1 is erected on the footing foundation F via the footing joint 2 in addition to the pier B. In a state where such a sheath tube 1 is erected, the peripheral edge of the pier B and the inner surface of the sheath tube 1 are separated by, for example, 10 to 20 cm, and this separated portion becomes a play space S in which earth and sand and water do not enter.

  As shown in FIGS. 4 and 5, the footing joint portion 2 is a rod-like member provided integrally with the sheath tube 1 so as to protrude downward between the sheath tube 1 and the footing foundation F constituting the dam body T. Embedded in an anchor bar 2c made of the above metal, a high elastic adhesive 2a as a high elastic anchor portion covering the anchor bar 2c provided on the footing base F, and a footing base F for injecting the high elastic adhesive 2a An anchor cap 2d, for example, a cylindrical container, a mortar 2g laid on the footing foundation F, and a buffer rubber as a buffer elastic material layer interposed between the mortar 2g and the sheath tube 1 2e.

In the present embodiment, the highly elastic adhesive 2a has an elongation capacity of 100% to 250% and a density of 0.7 to 1.2 g / cm ³ . As the high-elasticity adhesive 2a, for example, a material for an injection method or a material for a caulking method mainly composed of an epoxy resin main component and a modified silicone curing agent can be used. In addition to the main agent and the curing agent, an ultralight powder or the like is appropriately added to the highly elastic adhesive 2a in order to obtain the above density. The high elastic adhesive 2a is divided into four types according to the temperature conditions that change depending on the season and environment of construction, from the highest temperature to the one for the injection method: summer, general, winter and cold regions. Among them, the most suitable one for the caulking method can be selected from the three types for general use, winter use and cold district use. Furthermore, by appropriately adding a catalyst to the curing agent and controlling the reaction rate, it is possible to obtain an appropriate pot life suitable for the outside air temperature and to keep the construction completion time within an appropriate range suitable for the outside air temperature. it can. And in this embodiment, even if it is a case where any high elastic adhesive 2a is used, it is made for the tensile strength when concrete is adhere | attached to be 0.2 N / mm < ² > or more.

  Among the high elastic adhesives 2a, there is no difference in elongation ability between the one for the injection method and the one for the caulking method, but the one for the caulking method has characteristics that the density is slightly lower and the viscosity is higher. The high elastic adhesive 2a used for the footing joint 2 is considered to be more suitable for the injection method in view of the efficiency of the injection work into the anchor cap 2d at the time of construction.

  As shown in FIGS. 1 to 8, the sheath tube 1 is composed of a plurality of sheath tube blocks to which the sheath tube 1 is connected in the vertical direction. Specifically, the sheath tube 1 is a C-shape in which the C-shaped block 10a and the straight block 10b, which are each sheath tube block, are joined to each other by the horizontal joint 12 and are vertically stacked by the vertical joint 11. The blocks 10a and the linear blocks 10b are joined together.

  The horizontal joint portion 12 is a mechanical, mechanical connection with, for example, a coupling bracket and a bolt in a state where cushioning rubber (not shown) is interposed between the C-shaped block 10a and the linear block 10b which are the respective sheath tube blocks arranged in the horizontal direction. Various existing joining methods such as connection using a joint and connection using a PC steel rod can be applied. Therefore, in this embodiment, the specific structure and joining method and illustration of these horizontal joints 12 are omitted.

  As shown in FIGS. 4 and 6, the vertical joint portion 11 includes an anchor bar 11 c provided integrally with a C-shaped block 10 a or a straight block 10 b as an upper sheath tube block, and a lower side. A high-elasticity adhesive 11a as a high-elasticity anchor portion covering the anchor bar 11c provided on the C-shaped block 10a or the linear block 10b, and a lower C-shaped block 10a or An anchor cap 11d embedded in the straight block 10b, a cushioning rubber 11e which is an elastic material layer for cushioning interposed between the C-shaped block 10a which is the upper and lower sheath tube blocks or the straight block 10b, and a cushioning rubber which does not face the gap S A joint filling portion 11f made of a highly elastic adhesive filled in the joint portion formed on the outer surface side of 11e, and the joint filling portion 11f and the buffer Joint filling portion 11f formed of a high elastic adhesive is and a backup material 11b made of a non-polar substances which can not be adhered to between the rubber 11e.

  The high elastic adhesive disposed in the anchor cap 11d in the vertical joint 11 is the same as that used for the footing joint 2 in view of the efficiency of the injection work into the anchor cap 11d. It is desirable to use it. On the other hand, it is considered desirable to use a high-elasticity adhesive used for the joint filling portion 11f for the caulking method in order to further suppress dripping during filling.

  Therefore, in this embodiment, the earth and sand inflow prevention part 3 sealed with the high elastic adhesive 3a whose elongation ability is 100% to 250% between the sheath pipe 1 and the bridge pier B at the upper edge of the gap S as described above. It is characterized by comprising. As shown in FIGS. 4, 7, and 8, the earth and sand inflow prevention portion 3 mainly includes a high-elasticity adhesive 3 a that is disposed so as to be substantially flush with the upper surface of the sheath tube 1. In addition to the high elastic adhesive 3a, the earth and sand inflow prevention portion 3 includes an elastically deformable backup material 3b that supports the high elastic adhesive 3a from below, and an upper surface of the sheath tube 1 from the upper surface of the high elastic adhesive. And a surface protective agent 3h to be applied over the part. In the present embodiment, the backup material 3b is made of a nonpolar material such as polyethylene or polypropylene, which the high-elasticity adhesive 3a cannot adhere to. The highly elastic adhesive 3a used for the earth and sand inflow prevention part 3 is applied to the upper surface of the backup material 3b laid without gaps between the pier B and the sheath tube 1 at the time of construction, and the liquid surface is disposed on the upper surface of the sheath tube 1. However, it is considered that it is desirable to use the one for the caulking method in order to further suppress the downward sag during the construction. As the surface protective agent 3h, an appropriate paint or the like that can protect the highly elastic adhesive 3a from ultraviolet rays or wind and rain caused by solar radiation can be used.

  In the present embodiment, the separation dimension of the sheath pipe 1 and the pier B at the upper edge of the free space S due to a difference in vibration characteristics between the pier B and the dam body T from an ordinary state shown in FIG. For example, even if the separation dimension temporarily increases as shown in FIG. 5B, the high elastic adhesive 3a exhibits a value of 100% to 250% in elongation capacity. 1 and the upper edge of the play S can be maintained in a sealed state while maintaining the bonding of the bonding surface 3a1 bonded to the pier B. In particular, in the present embodiment, the backup material is a non-polar substance to which the high elastic adhesive cannot be bonded. Therefore, the high elastic adhesive is bonded to the sheath tube 1 and the pier B as shown in FIG. When the adhesive surface 3a2 facing the backup material is appropriately separated from the backup material 3b while maintaining the adhesion of the adhesive surface 3a1, the elongation capability is exhibited without interference with the backup material 3b.

  With the above-described configuration, in the sheath tube structure X according to the present embodiment, the high elastic adhesive appropriately expands and contracts even when the dimension of the gap S occurs due to vibration of the pier B and the sheath tube 1. The state where the upper end of the gap S is sealed is stably maintained. As a result, the sheath tube structure X that can maintain the strength of the levee and the pier B over a long period of time by stably maintaining the gap S over a long period of time is realized.

Moreover, in this embodiment, in order to ensure the required adhesive force, while making it easy to finish the earth-and-sand inflow prevention part 3 to a required shape, without dripping a highly elastic adhesive at the time of construction, it uses for the earth-and-sand inflow prevention part 3 in this embodiment. The high elastic adhesives 2a, 11a and 11f used not only in the high elastic adhesive 3a but also in other places are exclusively used in the density of 0.7 to 1.2 g / cm ^3. ing.

  In this embodiment, since the backup material 3b supports the highly elastic adhesive 3a in the earth and sand inflow prevention portion 3 from below, further improvement of vibration absorption capability due to simple construction and elasticity of the backup material 3b itself can be achieved. Both are compatible.

  In particular, in the present embodiment, the backup material 3b is made of a non-polar material such as polyethylene or polypropylene to which the high-elasticity adhesive 3a cannot be bonded. In addition to suppressing vibration by the backup material 3b, the high-elasticity adhesive 3a is bonded. A state where only the backup material 3b is in contact with the surface 3a2 without being bonded is realized. As a result, the high elastic adhesive 3a can fully exhibit the elongation ability of the high elastic adhesive 3a itself without being constrained by the backup material.

  Moreover, the footing junction part 2 is provided in this embodiment as a structure for relieving the vibration which arises in the sediment inflow prevention part 3 by encouraging absorption of the vibration by the side of the sheath pipe 1 side. As a result, the vibration is effectively suppressed by the relative movement of the high elastic adhesive 2a in the anchor bar 2c and the anchor cap 2d, so that not only the vibration suppression that occurs in the sediment inflow prevention part 3 but also the earthquake resistance of the sheath tube 1 itself. Has also improved. Further, as a specific configuration of the footing joint portion 2, a performance of absorbing vibration by arranging a mortar 2 g as a mortar layer and a buffer rubber 2 e as a buffer elastic material layer provided on the upper surface of the footing foundation F. Has been improved more.

  Further, in this embodiment, the sheath tube 1 is composed of a plurality of C-shaped blocks 10a and straight blocks 10b which are a plurality of sheath tube blocks connected in the vertical direction, and the anchor bar is covered with a highly elastic adhesive 11a which is a highly elastic anchor portion. Since the vibration is effectively suppressed by the relative movement of the high elastic adhesive 11a in the anchor bar 11c and the anchor cap 11d by providing the vertical joint portion 11 configured as described above, the sheath tube 1 itself also effectively vibrates. Can absorb. In addition, a cushioning rubber 11e, which is a cushioning elastic material layer, is interposed between the upper and lower C-shaped blocks 10a and the straight blocks 10b to further improve the performance of absorbing such vibration.

  In addition, in the present embodiment, by providing the joint filling portion 11f filled with the high elastic adhesive in the joint portion formed between the upper and lower C-shaped blocks 10a and the straight block 10b, the water tightness and the sealing performance of the sheath tube 1 itself are provided. Is further improved, and the invasion of earth and sand and water into Yuma S is effectively avoided. By interposing a backup material 11b made of a non-polar substance between the joint filling portion 11f and the cushioning rubber 11e, the joint filling portion 11f realizes a so-called two-sided adhesion state in which only the upper and lower concrete surfaces are adhered, and has high elasticity. The elongation ability of the adhesive itself is exhibited, and the watertightness of the sheath tube 1 itself is more effectively secured.

  Although the embodiment of the present invention has been described above, the specific configuration of each unit is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the above-described embodiment, the aspect in which the upper and lower casing tube blocks are connected only by the upper and lower direction joints that effectively utilize the performance of absorbing the vibration of the high elastic adhesive is disclosed. Alternatively, an existing joining method according to the above may be applied instead or in part. Needless to say, the shape of the sheath tube in plan view is not limited to that of the above-described embodiment, and may be an appropriate shape depending on the shape of the pier to be applied. Further, detailed modes including specific dimensions of the anchor bar and the anchor cap are not limited to those of the above embodiment, and various modes including the existing ones can be applied.

  In addition, the specific configuration of each part is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

  Examples of the present invention will be described below. In addition, the said Example does not limit this invention at all.

  And as described in the above embodiment, as the high-elasticity adhesive used in the present invention, a two-component adhesive of an epoxy resin and a modified silicone resin is applied to achieve both easy construction and excellent elongation capability. Yes.

In addition, since the high-elastic adhesive used in the present invention is an adhesive having a tensile strength of 0.2 N / mm ² or more when the concrete is bonded to each other, the vibration applied to the sheath tube during vibration during an earthquake. It is possible to effectively secure the water-tightness of the portion where the high-elastic adhesive is used.

  As an example of the present invention, the properties and physical properties of a highly elastic adhesive that can be used in the above embodiment will be described below.

  As the high-elasticity adhesive, a material for an injection method and a material for a caulking method, which have greatly different viscosities at the time of mixing, are appropriately used depending on the location and environment to which they are applied. Depending on the temperature conditions at the time of construction, high-elastic adhesives for the injection method are for winter, general use, summer and cold regions, while those for the caulking method are used for winter, general and cold regions. By applying the most suitable one, it is possible to realize easy and reliable construction from -5 ° C. to 40 ° C., that is, regardless of the construction location as well as the season and region.

  In this example, properties and physical properties are shown for a total of seven types of high-elastic adhesives for the injection method and the caulking method, respectively, and the results of the tensile adhesion strength test are shown. Further, the viscosity in this example was measured by a method according to JIS K 6833 “General test method for adhesive 6.3 Viscosity”. The specific gravity of the mixture was measured by a method according to JIS K 7112.

  Tables 1 and 2 show the properties and physical properties of the high-elastic adhesive (for winter) for the injection method.

Tables 3 and 4 show the properties and physical properties of the high-elasticity adhesive (for general use) for the injection method.

Table 5 and Table 6 show the properties and physical properties of the high-elasticity adhesive for summer (for summer), respectively.

Tables 7 and 8 show the properties and physical properties of the high-elasticity adhesive (for cold regions) for the injection method.

Each of the above-mentioned adhesives has a viscosity of 1000 to 12000 mPa · S, a pot life of 15 to 330 minutes, and a touch setting time of 1 hour until hardening is observed from the touch of the tester. The point which is -44 hours and the point whose density is 0.8-1.2 g / cm < ³ > were confirmed.

  Tables 9 and 10 show the results of the tensile adhesion strength test performed on the high-elastic adhesives for the above-described injection methods, respectively.

From the above, the maximum elongation of the four types of high-elastic adhesives (in the summer, general use, winter, and cold districts) for the injection method in the state of being bonded to the concrete surface is low even at low temperatures (0 ° C). It was confirmed that the allowable axial displacement amount, that is, the elongation capacity of the joint portion assuming level 2 earthquake motion is 100% or more, which is equal to or higher than that at room temperature (20 ° C.). Furthermore, it was also confirmed that any adhesive had a tensile strength of 0.2 N / mm ² or more and an elongation capacity of 250% or more, which was the adhesion strength at the time of the test.

  Subsequently, Table 11 and Table 12 show the properties and physical properties of the high-elasticity adhesive (for general use) for the caulking method.

Table 13 and Table 14 show the properties and physical properties of the high-elastic adhesive (for winter) for the caulking method.

Table 15 and Table 16 show the properties and physical properties of the high-elastic adhesive (for cold districts) for the caulking method.

Each of the above-mentioned adhesives has a viscosity of 100,000 to 530000 mPa · S, a pot life of 30 to 270 minutes, and a finger touch curing time of 4 hours from the tester's finger touch until hardening is observed. It was confirmed that the point was ˜60 hours and the density was 0.7 to 1.1 g / cm ³ .

  Tables 17 and 18 show the results of tensile adhesion strength tests performed on the above-described high-elastic adhesives for the respective caulking methods.

From the above, the maximum elongation of the three types of high-elastic adhesives for the caulking method (general use, winter use, and cold district use) in the state of being bonded to the concrete surface is the normal temperature even at low temperatures (0 ° C) ( It was confirmed that the allowable axial displacement amount, that is, the elongation capacity of the joint part assuming level 2 seismic motion is 100% or more.

  INDUSTRIAL APPLICABILITY The present invention can be used as a sheath tube structure in which a sheath tube is provided so as to form a gap between a bank body constituting a bank and a bridge pier standing in the bank body.

X ... sheath tube structure 1 ... sheath tube 10a ... sheath tube block (C-shaped block)
10b ... sheath tube block (straight block)
11 ... Vertical joint 11a ... High elastic anchor part (high elastic adhesive)
11c ... Anchor bar 2 ... Footing joint 2a ... High elastic anchor (high elastic adhesive)
2c ... Anchor bar 3 ... Sediment inflow prevention part 3a ... High elastic adhesive 3b ... Back-up material F ... Footing foundation B ... Bridge pier S ... Yuma T ... Dam body

In other words, the sheath pipe structure according to the present invention has an annular shape in plan view through a bridge pier made of concrete standing in the levee body constituting the levee and a space that is a space having a predetermined size in plan view around the pier. A sheath pipe that is a concrete product that is provided apart from the pier and that is covered with earth and sand to the extent that the upper end portion is exposed to the ground surface, and at the upper edge between the play, the sheath pipe and the pier With a highly elastic adhesive having an elongation capacity of 100% to 250% and a tensile strength of 0.2 N / mm ² or more when the concrete is bonded to each other so as to be substantially flush with the upper surface of the sheath tube. It is characterized by having a sealed earth and sand inflow prevention part.

Claims (6)

A concrete pier that is erected in the embankment that constitutes the embankment;
A sheath pipe which is a concrete product provided in a ring shape in plan view through a play space which is a space having a predetermined size in plan view around the pier,
A sheath tube structure comprising a sediment inflow prevention portion sealed with a highly elastic adhesive having an elongation capacity of 100% to 250% between the sheath tube and the pier at the upper edge of the play. The sheath tube structure according to claim 1, wherein the density of the highly elastic adhesive is 0.7 to 1.2 g / cm ³ . The sheath pipe structure according to claim 1 or 2, wherein the earth and sand inflow prevention portion includes the high elastic adhesive and an elastically deformable backup material that supports the high elastic adhesive from below. The sheath tube structure according to claim 3, wherein the backup material is made of a nonpolar substance to which the high-elastic adhesive cannot adhere. Between the sheath pipe and the footing foundation constituting the dam body, the anchor bar is provided so as to protrude downward integrally with the sheath pipe and the high elastic adhesive provided on the footing foundation. The sheath tube structure according to claim 1, 2, 3 or 4, further comprising a footing joint portion having a highly elastic anchor portion covering the anchor bar. The sheath tube is composed of a plurality of sheath tube blocks connected in the vertical direction,
A high-elasticity anchor portion that covers the anchor bar, comprising an anchor bar provided integrally with the upper casing tube block and the high-elastic adhesive provided on the lower sheath tube block; The sheath tube structure according to claim 1, 2, 3, 4, or 5, wherein the sheath tube structure has a vertical joint portion.