JP7211809B2 - Driftwood catcher, method for constructing driftwood catcher, and installation structure for driftwood catcher - Google Patents

Description

This invention relates to a dam constructed in the transverse direction of a river for the purpose of erosion control, erosion control, etc. (hereinafter collectively referred to as "sabo dam"). Belongs to the technical field.
The erosion control dam may be existing or newly constructed. In addition, although the target is mainly an opaque type, a transmissive type may also be used.

In recent years, driftwood trapping countermeasures have been promoted, and in order to more efficiently prevent disasters downstream, there is a demand to attach a driftwood trapping work (driftwood trapping function) to the erosion control dam.
However, when the driftwood trapping work is retrofitted to the erosion control dam, the strength of the erosion control dam itself is insufficient, so it is necessary to cast more concrete. There were various problems such as difficulty in obtaining sufficient driftwood trapping ability due to the presence of
Therefore, in recent years, there has been disclosed a technique for installing a driftwood trapping structure separated from the erosion control dam upstream of the erosion control dam (see, for example, Patent Document 1).

Patent Document 1 discloses a capture body (driftwood trapping work) 3 configured separately from the dam 2 in the sedimentation area on the upstream side of the dam 2 so that FIG. 2 of the same document 1 can be easily understood. ing.
The trapping body 3 includes one beam 31 extending along the extending direction of the dam 2, and a plurality of pillars 32 connected at predetermined intervals along the extending direction of the beam 31. , and a base portion 33 for holding the column portion 32 are integrally formed. The base portion 33 is formed of a large-scale continuous bottom slab concrete in which all of the plurality of column portions 32 are erected collectively (see paragraph [0026] of the specification for details).

According to Patent Document 1, it is recognized that the capture body 3 can be installed effectively without modifying the existing dam 2, and the cost and time required for construction can be suppressed (description paragraph [0021] (effect of the invention)).

JP 2017-72020 A

However, the trapping body (driftwood trapping work) 3 according to Patent Document 1 constructs a large-scale continuous base portion 33 for collectively (integrally) erecting all of the plurality of pillars 32. , a large amount of concrete is inevitably required, and there is a problem that the cost increases. Considering the transportation of concrete to the mountainous area and the work of placing it, it was also very complicated.
In addition, since the sedimentation area on the upstream side of the dam 2 has a loose ground, if uneven settlement occurs, the effect will extend to the entire base portion 33, so that the trapping body (driftwood trapping work) 3 will not function. was concerned.
Furthermore, the repair work for the trapping body (driftwood trapping work) 3 was also large-scale and troublesome.

The present invention has been devised in view of the above-mentioned problems of the background art, and the object thereof is to provide a driftwood catcher which is separated from and adjacent to the dam upstream of the dam. By separating the foundations from each other, the amount of concrete used can be reduced, and it can be installed in an optimal arrangement where countermeasures are required. To provide a construction method for a body and a driftwood catching body, and an installation structure for the driftwood catching work.

As a means for solving the above problems, the driftwood catcher according to the invention described in claim 1 is a driftwood catcher installed on the upstream side of a erosion control dam,
The driftwood catcher includes a closed cross-section forming member that forms a closed cross-section space, a filling material that fills the closed cross-section space, and a pile that protrudes downward from the closed cross-section space and is fixed to the filling material. It is characterized by comprising a foundation and a driftwood capturing column member that rises from the closed cross-sectional space and is fixed to the filling material.

The invention recited in claim 2 is characterized in that, in the driftwood trapping body recited in claim 1, the pile foundation and the driftwood trapping column member are connected in series with a mechanical joint.

The invention described in claim 3 is the driftwood capturing body described in claim 1, wherein the driftwood capturing column member is detachably inserted into a sheath pipe provided in the closed cross-sectional space and fixed to the filling material. It is characterized by a configuration in which it rises by

The invention recited in claim 4 is the driftwood trap recited in claim 3, wherein the pile foundation is joined to the bottom surface of the sheath pipe.

The invention recited in claim 5 is the driftwood trapping body recited in claim 3, wherein the pile foundation is provided so as to be movable relative to a guide frame vertically installed on the sheath pipe. do.

The invention recited in claim 6 is characterized in that, in the driftwood trapping body recited in any one of claims 1 to 5, the projecting portion of the pile foundation is also fixed.

A driftwood trap according to a seventh aspect of the invention is a driftwood trap installed upstream of an erosion control dam, wherein the driftwood trap includes a closed cross-section forming member that forms a closed cross-section space; It is characterized by comprising a filling material filled in the cross-sectional space and a driftwood capturing column member erected so as to vertically penetrate the closed cross-sectional space and fixed to the filling material.

The invention recited in claim 8 is characterized in that, in the driftwood trapping body recited in claim 7, a portion of the driftwood trapping column member protruding downward from the closed cross-sectional space is also fixed.

A ninth aspect of the present invention is the driftwood trap according to any one of the first to eighth aspects, wherein the closed cross-section forming member is constructed by connecting a plurality of segments.

The invention recited in claim 10 is characterized in that, in the driftwood trapping body according to any one of claims 1 to 9, the driftwood trapping column member is one or a plurality of pieces.

The invention according to claim 11 is the driftwood trap according to any one of claims 1 to 10, wherein the closed cross-section forming member is formed in a circular shape, an oval shape, or a rectangular shape when viewed in plan. It is characterized by being

The invention according to claim 12 is the driftwood trap according to any one of claims 3 to 6 and 9 to 11, wherein the sheath pipe is formed in a cylindrical shape with a bottom. .

The invention according to claim 13 is the driftwood trap according to any one of claims 3 to 6 and 9 to 12, wherein the upper end of the sheath pipe is substantially flush with the surface of the filling material. It is characterized by being embedded.

A construction method for a driftwood trap according to the invention described in claim 14 is a construction method for a driftwood trap to be installed upstream of an erosion control dam,
A step of erecting a closed cross-section forming member that forms a closed cross-section space at a predetermined location on the upstream side, and installing a pile foundation in a configuration that protrudes downward from the closed cross-section space;
a step of joining a driftwood capturing column member to the upper end of the pile foundation and standing up from the closed cross-sectional space;
filling the closed cross-sectional space with a filling material to fix the pile foundation and the driftwood capturing column member.

A construction method for a driftwood trap according to the invention described in claim 15 is a construction method for a driftwood trap to be installed upstream of an erosion control dam,
A structure in which a closed cross-section forming member that forms a closed cross-section space is erected at a predetermined location on the upstream side, and a pile foundation provided with a bottomed cylindrical sheath pipe at the upper end protrudes downward from the closed cross-section space. A process of installing with
a filling material is filled in the closed cross-sectional space to fix the pile foundation and the sheath pipe, and a driftwood capturing column member is inserted into the sheath pipe and erected. .

A construction method for a driftwood trap according to the invention described in claim 16 is a construction method for a driftwood trap to be installed upstream of an erosion control dam,
a step of erecting a closed cross-section forming member that forms a closed cross-section space at a predetermined location on the upstream side, and installing a driftwood capturing column member so as to vertically penetrate the closed cross-section space;
filling the closed cross-sectional space with a filling material to fix the driftwood capturing column member.

The installation structure of the driftwood trap according to the invention described in claim 17 is an installation structure of a driftwood trap installed on the upstream side of a sabo dam,
The driftwood trapping work is composed of a plurality of driftwood traps according to any one of claims 1 to 13, and the plurality of driftwood traps are configured so that the distance between the driftwood trapping pillar members is 1/3 of the assumed maximum length of driftwood. It is characterized by being spaced by about 1/2 and installed in a proper arrangement to catch the assumed driftwood.

The invention recited in claim 18 is the installation structure for the driftwood trapping work recited in claim 17, wherein the plurality of driftwood traps are spaced apart in an approximately linear arrangement in the river transverse direction. Characterized by

The invention described in claim 19 is the installation structure for the driftwood trapping work described in claim 17, wherein the plurality of driftwood traps are spaced apart to form a substantially fan shape or a substantially inverted fan shape. It is characterized by

The invention recited in claim 20 is the installation structure for the driftwood trapping work recited in claim 17, wherein the plurality of driftwood trapping bodies are spaced apart in a meandering arrangement along the transverse direction of the river. Characterized by

ADVANTAGE OF THE INVENTION According to the driftwood trapping body, the construction method of the driftwood trapping body, and the installation structure of the driftwood trapping structure according to the present invention, the following effects can be obtained.
(1) The diameter of each driftwood catcher is about 2.5m (more or less than about 2.5m is acceptable), and it can be installed in a sedimentation area (sand bed) with an independent foundation. Not only can it be implemented with a separate structure, but also adjacent driftwood traps can be implemented with a structure that is separated from each other, eliminating the need for a large-scale continuous bottom slab concrete base as in the past.
Therefore, the amount of concrete to be used can be suppressed, and a plurality of driftwood traps can be installed in an optimal arrangement at the location where countermeasures are required (see FIGS. 1, 4, and 5, etc.). It is possible to realize a highly efficient driftwood trap, a construction method for the driftwood trap, and an installation structure for the driftwood trap.
(2) The driftwood trapping body according to the present invention can effectively increase the resistance to running water by implementing a so-called pile foundation structure. As a result, the size of the driftwood catcher itself can be reduced. Therefore, it is economical and flexible.
(3) The form of the driftwood catcher can be changed in design according to the topography of the sedimentation area (see Fig. 5). Depending on the properties, it may be arranged in a single arrangement or in multiple arrangements, and in the case of multiple arrangements, in addition to random arrangement, it can be installed in a substantially linear arrangement in the river transverse direction (see Fig. 1 etc.), or in a fan shape ( 4B), or in an arrangement that forms an approximately inverted sector (see FIG. 4A), or in a meandering arrangement along the transverse direction of the river. For example, according to the topography of the sedimentation area and the properties of the sedimentation area at the installation location, the driftwood trapping body according to FIG. 2, the driftwood trapping body according to FIG. 6, and the driftwood trapping body according to FIG. can also
(4) Since it is implemented with an independent foundation, even if the driftwood trapping body sinks or falls, it does not affect the other driftwood trapping columns. If damaged, it can be dealt with by repairing the damaged driftwood catcher, which is economical and rational.
(5) Since it is implemented on an independent foundation, it can be constructed without being affected by the progress of the construction work of the adjacent driftwood trap, and there are no restrictions on the order of installation of the driftwood trap, and it can be installed for several years. It is possible to easily perform division construction, addition and removal of facilities.
(6) For example, when a liner plate is used, earth retention and temporary coffering are possible, pumping up is easy even at a site with groundwater, and dry construction is also possible, resulting in excellent workability.

A is a plan view schematically showing a state in which a driftwood trap according to the present invention is installed on the upstream side of a dam, and B is an elevation view of the same. 1 is an elevational view showing Embodiment 1 of the driftwood trapping body according to the present invention, B is an elevational cross-sectional view of the same, and C is a plan view of the same. A to C are explanatory diagrams showing step by step the method of attaching the driftwood catching column member to the sheath pipe, and D and E are plan cross-sectional views showing the main part of C. FIG. 7A and 7B are plan views schematically showing variations of the state in which the driftwood catcher according to the present invention is installed on the upstream side of the dam; FIG. 4A and 4B are variation diagrams of the state in which the driftwood catcher according to the present invention is installed on the upstream side of the dam, viewed from the upstream side. Fig. 2 is an elevational view showing Example 2 of the driftwood catcher according to the present invention; A is an explanatory diagram showing a joint portion between the pile foundation of the driftwood trapping body and the driftwood trapping column member according to FIG. be. A is an explanatory diagram showing a joint portion between the pile foundation of the driftwood trapping body and the driftwood trapping column member according to FIG. be. FIG. 7 is a variation diagram in which the protrusion dimension of the pile foundation of the driftwood catcher according to FIG. 6 is adjusted to be long. FIG. 7 is a variation diagram in which the protrusion dimension of the pile foundation of the driftwood catcher according to FIG. 6 is adjusted to be longer. Fig. 10 is an elevational view showing Example 3 of the driftwood catcher according to the present invention; FIG. 11 is an elevational view showing a variation of the third embodiment of the driftwood catcher according to the present invention; It is the top view which showed roughly the variation of the driftwood catcher which concerns on this invention, and B is the same elevation view. It is the top view which showed roughly the variation of the driftwood catcher which concerns on this invention, and B is the same elevation view.

Next, embodiments of the driftwood trapping body, construction method of the driftwood trapping body, and installation structure of the driftwood trapping structure according to the present invention will be described with reference to the drawings.

1A and 1B show an implementation of catching driftwood flowing from the upstream side of a river by installing a plurality of driftwood capturing bodies 1 according to the present invention (five bodies in a straight line in the illustrated example) on the upstream side of a sabo dam 10. shows an example. Incidentally, the symbol S in the figure indicates the Yuanxi floor surface, and the symbol T indicates the sedimentation surface.

As shown in FIG. 2, the driftwood catcher 1 includes a closed cross-section forming member 2 that forms a closed cross-section space, a filling material 3 that fills the closed cross-section space, and a It consists of a pile foundation 4 protruding and fixed to the filling material 3 and a driftwood capturing column member 5 rising from the closed section space and fixed to the filling material 3 .

In this embodiment, the closed cross-section forming member 2 is constructed by connecting a plurality of segments 12 having required strength and rigidity. More specifically, as an example, a cylinder having an outer diameter of about 2.5 m is formed into an arc shape equivalent to roughly five equal divisions in the circumferential direction, and flanges protruding inward are provided at the top, bottom, left, and right ends. liner plate 12 having a height of about 50 cm.
The closed cross-section forming member 2 according to FIG. 2 has five liner plates 12 in the circumferential direction (see FIG. 2C) and four liner plates 12 in the axial direction, which are flange-connected in a staggered manner. It is built in a cylindrical shape with a height of about 2m.

Note that the shape and size of the liner plate 12 are not limited to those described above, and can be appropriately changed in design according to the structural design. Of course, the shape and size of the closed cross-section forming member 2 are not limited to those described above, and can be appropriately changed in design according to the structural design.
However, the member constituting the closed cross-section forming member 2 is not limited to the liner plate 12, and any member having the required strength and rigidity to form the closed cross-section space may be used. For example, steel segments, PC segments, corrugated pipes, steel plate cells, steel sheet pile cells, large-diameter pipes, or formwork can be used as well. When the formwork is used, the concrete 3 can be removed (demolded) after curing.
The same technical concept applies to the embodiments described below.

Although the filling material 3 is concrete 3 in this embodiment, it is not limited to this, and soil cement can be used in the same manner.
The pile foundation 4 is embedded below the closed cross-section forming member 2 installed in the sedimentation area, thereby increasing the resistance to flowing water and rationally and effectively against the hydraulic power of the river. provided to resist. Therefore, the compactness of the closed cross-section forming member 2 can be rationally realized. In this embodiment, as an example, a round steel pipe having an outer diameter of about 320 mm and a height of about 2600 mm is used, the upper half of which is positioned inside the closed cross-section forming member 2 (closed cross-section space), and the lower It is implemented in a configuration in which half of it is embedded (embedded) in the sedimentation area.
In this embodiment, a sheath pipe 6 for detachably inserting and erecting the driftwood trapping column member 5 is integrally provided at the upper end of the pile foundation 4 by joining means such as welding. there is

The sheath pipe 6 is formed in a metallic cylindrical shape with a bottom made of a square steel pipe and a base plate. It is positioned in the upper part of the approximate center of the space. More specifically, the upper end of the sheath pipe 6 and the upper end of the closed cross-section forming member 2 are substantially leveled so that the concrete 3 to be filled does not enter the inside of the sheath pipe 6, and the surface of the concrete 3 is It is positioned at a site to be embedded substantially flush with.
As an example, the size of the sleeve tube 6 according to the present embodiment is about 650 mm in height, about 700 mm in one side of the base plate, about 500 mm in width of the rectangular steel pipe portion on the upper surface of the base plate, and about 9 mm in thickness. .

The driftwood trapping column member 5 is made of a metal round steel pipe, is detachably inserted into the sheath pipe 6, and stands vertically.
As an example of the size of the driftwood trapping column member 5 according to this embodiment, the height including the hanging metal fitting provided at the top is about 2800 mm, the outer diameter of the round steel pipe is about 320 mm, and the wall thickness is about 10 mm. It is

To further explain the configuration in which the driftwood capturing column member 5 is inserted into the sheath tube 6 and erected, in this embodiment, as illustrated in FIG. It has two vertical members 11 protruding in a symmetrical arrangement in the radial direction, and the sheath pipe 6 has horizontal members 13 for holding the vertical posture of the driftwood trapping column member 5 on two opposite sides of its inner wall surface. and a stopper member 14 vertically provided on the horizontal member 13 .
The positional relationship of the vertical member 11, horizontal member 13 and stopper member 14 is such that the lower end of the driftwood trapping column member 5 is set vertically into the sheath pipe 6 as shown step by step in FIGS. When it is inserted and rotated counterclockwise (or clockwise), the vertical members 11, 11 of the driftwood catching column member 5 hit the stopper members 14, 14 at the same time, making it impossible to pull out ( See also Figures 3D, E). The gap formed between the inner surface of the sheath pipe 6 and the outer peripheral surface of the driftwood trapping column member 5 is appropriately filled with locally generated soil or sand.

Of course, the configuration of inserting the driftwood catching column member 5 into the sheath pipe 6 and erecting it is not limited to the above. The design can be changed as appropriate on the condition that it can be erected (for example, see WO2013/042735, which has already been filed by the present applicant and has been internationally published).
Incidentally, it should be noted that the vertical member 11, the horizontal member 13, and the stopper member 14 are appropriately omitted in drawings other than FIG. 3 for convenience of illustration.

Next, a method for constructing the driftwood catcher 1 will be described.
The construction method of the driftwood trapping body 1 according to the present invention is a construction method of the driftwood trapping body 1 installed on the upstream side of the erosion control dam 10, wherein a closed cross-section space is formed at a predetermined location on the upstream side. A step of erecting the forming member 2 and installing a pile foundation 4 having a bottomed cylindrical sheath pipe 6 at the upper end so as to protrude downward from the closed cross-sectional space; It consists of a step of filling the filling material (concrete) 3 to fix the pile foundation 4 and the sheath pipe 6, inserting the driftwood capturing column member 5 into the sheath pipe 6, and erecting it.

When the closed cross-section forming member 2 is implemented as a liner plate 12 as in this embodiment, it is assembled three-dimensionally by flange connection in the circumferential and axial directions. Although the closed cross-section forming member 2 according to the illustrated example has a circular shape in a plan view, it may have an oval shape (see FIG. 13) or a rectangular shape. In addition, since the closed cross-section forming member 2 according to the illustrated example is implemented at a height of about 2 m, it is usually implemented by a floor excavation (open cut) construction method. When constructing the forming member 2, it is preferable to use the reverse winding construction method. In addition, when using a member other than the liner plate 12 (see paragraph [0034] above), the closed cross-section forming member 2 is constructed by a method according to the characteristics of each member.
When the closed cross-section forming member 2 is implemented by a driftwood catcher 51 formed in an oval shape when viewed from above as shown in FIG. The support member 18 is appropriately installed as necessary.
The same technical concept applies to the embodiments described below.

The pile foundation 4 is integrated with (the bottom surface of) the sheath pipe 6 at its upper end by joining means such as welding. It is positioned substantially in the central part of the space, embedded vertically in the sedimentation area, and concrete 7 is placed around the embedded part. During this operation, the upper end of the sheath tube 6 and the upper end of the closed cross-section forming member 2 are substantially aligned.
In this embodiment, the embedding dimension (projection dimension below the closed cross-sectional space) is set to about 1300 mm, but the strength of the sedimentation area where the pile foundation 4 is embedded and the required driftwood trapping body It can be appropriately increased or decreased according to the structural design such as the rigidity of 1.
Further, in this embodiment, concrete 7 is placed and fixed in order to stabilize the erected state of the pile foundation 4, but instead of the concrete 7, soil cement can be used in the same manner. This determination is made by appropriately considering the ground properties (strength, etc.) of the sediment area in which the pile foundation 4 is embedded, the required rigidity of the driftwood trapping body 1, and the like.

Thus, the closed cross-section forming member 2 is constructed at a desired portion and at a desired height, a pile foundation 4 is erected substantially in the center of the closed cross-section space, and a sheath pipe 6 integrally joined to the upper end thereof. When the upper end of the closed cross-section forming member 2 and the upper end of the closed cross-section forming member 2 are aligned at substantially the same height level, next, concrete 3 is filled (placed) in the closed cross-section space. The concrete 3 according to this embodiment is filled up to the extent that it reaches the top end of the closed cross-section forming member 2 (and the sheath tube 6). Concurrently with this filling operation, the driftwood trapping column member 5 is inserted into the sheath pipe 6 and erected (see paragraph [0038] above for details).
In addition, the standing position of the pile foundation 4 and the sheath pipe 6 is not limited to the substantially central position of the closed cross-sectional space in a plan view, and can be appropriately changed in design.

Therefore, the driftwood trapping body 1 constructed by the construction method of the driftwood trapping body 1 described above has a diameter of about 2.5m per body (it can be about 2.5m or more or less) and is an independent foundation type in the sedimentation area. Since it can be installed, not only can it be implemented with a structure separated from the erosion control dam 10, but also the adjacent driftwood trapping bodies 1, 1 can be implemented with a structure separated from each other. does not require a part.
Therefore, the amount of concrete to be used can be suppressed, and a plurality of driftwood traps can be installed in an optimal arrangement at locations requiring countermeasures (see FIGS. 1, 4, 5, etc.).
Specifically, the form of the driftwood catcher 1 can be appropriately changed in design according to the topography 9 (see FIG. 5) of the sedimentation area. Depending on the properties such as height, a single arrangement or multiple arrangements may be used. In the case of multiple arrangements, in addition to random arrangement, they can be installed at intervals in a substantially linear arrangement in the river crossing direction (see Fig. 1 and Fig. 4A). ), can be spaced apart in an arrangement that forms an approximately fan shape (see FIG. 4B) or approximately an inverted fan shape (see FIG. 4A), or can be spaced apart in an arrangement that meanders along the transverse direction of the river. .
By the way, it is preferable that the adjacent driftwood trapping bodies 1 are installed so that the distance between the driftwood trapping column members 5 is about 1/3 to 1/2 of the assumed maximum length of driftwood.

6 to 10 show the driftwood catcher 21 according to the second embodiment.
The driftwood trapping body 21 according to the second embodiment is configured such that the pile foundation 4 is relatively movable with respect to the sheath pipe 6 in comparison with the first embodiment. The main difference is that the protrusion size of is implemented in an adjustable configuration. The same reference numerals are given to the same members as in the first embodiment, and the description thereof will be omitted as appropriate.

Specifically, in the driftwood catcher 21 according to the second embodiment, a pair of left and right guide frames 8, 8 that are long in the vertical direction are provided on the lower surface of the base plate of the sheath pipe 6, and the pile foundation (round steel pipe) 4 is interposed therebetween. It is installed vertically in an arrangement sandwiched between A plurality of bolt through holes 8a, 4a (four each in this embodiment) are provided at predetermined intervals along the corresponding vertical axis lines of the pair of guide frames 8, 8 and the pile foundation 4. is provided. Support bolts 15 are passed through the bolt holes 8a, 4a, and both ends of the support bolts 15 are fastened with nuts 16, 16, so that the pile foundation 4 is connected to the pair of guide frames 8, 8. (See FIGS. 6, 9 and 10 for comparison).

In this way, the significance of implementing the pile foundation 4 in a configuration in which the pile foundation 4 is movable relative to the guide frames 8, 8 and thus the sheath tube 6, in other words, the downward protrusion dimension of the pile foundation 4 can be adjusted. The significance of implementing such a structure is mainly to respond quickly on site even if it is found that the foundation height is deep according to the ground properties of the sediment area excavated on site.

The pair of guide frames 8, 8 according to the present embodiment are made of metal members having a U-shaped cross section (C-shaped steel: 125 × 65 × 6 × 8 mm) with a height of about 1250 mm. The size of the base 4 is a round steel pipe having an outer diameter of about 320 mm and a height of about 2600 mm, which are the same as those of the first embodiment.
In addition, the bolt through holes 4a and 8a according to the present embodiment are, as an example, provided four at equal intervals with an interval of 250 mm. Can be changed.
Furthermore, the support bolts 15 that pass through the bolt through holes 4a and 8a and support the pile foundation 4 are preferably arranged in two stages, upper and lower, as in the present embodiment for the sake of stability. It is possible to implement it with (one line) or with three stages (three lines) or more.

The construction method of the driftwood trapping body 21 according to the second embodiment is the same as that of the first embodiment except that a step of adjusting the protrusion dimension is added when the pile foundation 4 is embedded. Therefore, the procedure is almost the same as that of the first embodiment (see paragraphs [0040] to [0043]). Further, the driftwood trapping body 21 after being filled with the concrete 3 has no difference in shape (appearance) from the driftwood trapping body 1 according to the first embodiment.
Therefore, the driftwood trapping body 21 constructed by the method for constructing the driftwood trapping body 21 according to the second embodiment has no difference in appearance from the driftwood trapping body 1 according to the first embodiment, and thus has the same function as that of the first embodiment. (See [0044] above for details).
It should be noted that the filling material 3 is not limited to the concrete 3, and the upright position of the pile foundation 4 and the sheath pipe 6 is not limited to the substantially central position of the closed cross-sectional space when viewed from above in the first embodiment. is similar to

FIG. 11 shows a driftwood catcher 31 according to the third embodiment.
Unlike the first and second embodiments, the driftwood trapping body 31 according to the third embodiment directly connects the pile foundation 4 and the driftwood trapping column member 5 by a mechanical joint 17 without providing a sheath pipe 6. The difference is that they are bolted in series. Another difference is that the height of the closed cross-section forming member 2 is reduced to about 1.5 m by reducing the number of stages of the liner plates 12 to three. The same reference numerals are given to the same members as in the first and second embodiments, and the description thereof will be omitted as appropriate.

Specifically, the driftwood catcher 31 according to the third embodiment includes a closed cross-section forming member 2 that forms a closed cross-section space, concrete (filling material) 3 that fills the closed cross-section space, and the closed cross-section It consists of a pile foundation 4 projecting downward from the space and fixed to the concrete (filling material) 3, and a driftwood capturing column member 5 rising from the closed cross-sectional space and fixed to the concrete (filling material) 3, The pile foundation 4 and the driftwood trapping column member 5 are connected in series with a mechanical joint 17 .

The construction method of the driftwood trapping body 31 having the above configuration is a construction method of the driftwood trapping body 31 installed on the upstream side of the erosion control dam 10, wherein a closed cross-sectional space is formed at a predetermined location on the upstream side. A step of erecting the member 2 and installing the driftwood capturing column member 5 integrated with the pile foundation 4 so as to vertically penetrate the closed cross-sectional space; material) 3 to fix the pile foundation 4 and the driftwood trapping column member 5.

After the pile foundation 4 is installed, the work of joining the driftwood trapping column member 5 to the upper end portion of the pile foundation 4 may be performed. In this case, the construction method of the driftwood catcher 41 is to erect the closed cross-section forming member 2 that forms a closed cross-section space at a predetermined location on the upstream side, and to project the pile foundation 4 downward from the closed cross-section space. a step of joining a driftwood capturing column member 5 to the upper end of the pile foundation 4 and raising it from the closed cross-sectional space; and a step of fixing the driftwood catching column member 5.

Therefore, the driftwood trapping body 31 constructed by the method for constructing the driftwood trapping body 31 according to the third embodiment is about 50 cm lower in height than the driftwood trapping bodies 1 and 21 according to the first and second embodiments. Since there is no difference except that, the same effect as the above-mentioned Examples 1 and 2 can be obtained (see [0044] above for details).
In addition, as shown in FIG. 12, the driftwood trapping column member 5 may be made into an elongated single piece, and may be configured to serve as the pile foundation 4 as well. In this case, the closed cross-section forming member 2 that forms the closed cross-section space is erected, and the elongated driftwood capturing column member 5 that also serves as the pile foundation 4 is configured to vertically penetrate the closed cross-section space. and a step of filling the closed cross-sectional space with concrete 3 to fix the elongated driftwood trapping column member 5 .
It should be noted that the filling material 3 is not limited to the concrete 3, and the standing position of the pile foundation 4 and the driftwood trapping column member 5 is not limited to the substantially central position of the closed cross-sectional space when viewed from above. Same as Example 1.

By the way, according to the method of constructing the driftwood trapping body 31 described above, the driftwood trapping column member 5 can be positioned and fixed in advance at a predetermined position before filling the concrete 3, so that the driftwood trapping body 31 can be placed in the closed cross-sectional space. can be completed in one time.
In other words, when the concrete 3 is placed in two steps, there is no need to position and fix the driftwood catching column member 5 in advance, and the pile foundation 4 and the driftwood catching column member 5 are separated. It can also be carried out in a state where
In this case, after installing the closed cross-section forming member 2 and the pile foundation 4 at a predetermined location, the first concrete filling operation is performed to a predetermined height in the closed cross-section space, and after curing the concrete. Next, the driftwood trapping column member 5 is erected vertically on the upper surface of the cured concrete, and the second concrete filling operation is performed up to the top of the closed cross-sectional space.

Although the embodiments have been described above with reference to the drawings, the present invention is not limited to the illustrated embodiments, and is subject to design changes and application variations that are normally made by those skilled in the art without departing from the technical idea of the present invention. Just a reminder to include ranges.

For example, like the driftwood trapping body 61 shown in FIG. 14, it is also possible to widen the plane area of the closed cross-section space and provide two driftwood trapping column members 5 in the closed cross-section space.
As an example, the closed cross-section forming member 2 related to the driftwood catcher 61 is formed in an arc shape equivalent to dividing a cylinder having an outer diameter of about 4.5 m into approximately nine equal parts in the circumferential direction. is implemented with a liner plate 12 having a height of the order of 50 cm, provided with an inwardly projecting flange. The closed cross-section forming member 2 according to the illustrated example has nine liner plates 12 in the circumferential direction and four liner plates 12 in the axial direction that are flange-connected in a zigzag manner, and has a diameter of about 4.5 m and a height of about 2 m. It is constructed in a cylindrical shape. Two sheath pipes 6 are installed in the closed cross-sectional space at a distance of about 1/3 to 1/2 of the assumed maximum driftwood length.
In addition, in the third embodiment, the vertically long driftwood capturing column members 5, 5 are inserted into the two sheath pipes 6, 6, respectively, but the present invention is not limited to this. For example, although illustration is omitted, the two sleeve pipes 6, 6 are provided in the direction of the flow of the river and are provided with an appropriate inclination, and are arranged in an A-shaped configuration in a side view (a so-called A-type slit dam) in which the legs are spread in the direction of the flow of the river. ), or by inserting the leg portion of the driftwood capturing column member having an inserted shape or the like to stand up.

1 Driftwood Catcher 2 Closed Section Forming Member 3 Filling Material (Concrete)
4 Pile Foundation 4a Bolt Through Hole 5 Driftwood Capture Column Member 6 Sheath Pipe 7 Concrete 8 Guide Frame 8a Bolt Through Hole 9 Terrain 10 Sabo Dam 11 Vertical Member 12 Liner Plate (Segment)
13 Horizontal member 14 Stopper member 15 Support bolt 16 Nut 17 Mechanical joint 18 Support member 21 Driftwood catcher 31 Driftwood catcher 41 Driftwood catcher 51 Driftwood catcher 61 Driftwood catcher S Genkei floor T Sedimentation surface

Claims (20)

A driftwood trap installed on the upstream side of an erosion control dam,
The driftwood catcher includes a closed cross-section forming member that forms a closed cross-section space, a filling material that fills the closed cross-section space, and a pile that protrudes downward from the closed cross-section space and is fixed to the filling material. A driftwood trap comprising a foundation and a driftwood trapping column member rising from the closed cross-sectional space and fixed to the filling material. 2. The driftwood trapping body according to claim 1, wherein said pile foundation and said driftwood trapping column member are connected in series with a mechanical joint. 2. The driftwood trapping apparatus according to claim 1, wherein said driftwood trapping column member is constructed so as to be detachably inserted into a sheath pipe provided in said closed cross-sectional space and fixed to said filling material. body. 4. The driftwood trap according to claim 3, wherein the pile foundation is joined to the bottom surface of the sheath pipe. 4. The driftwood catcher according to claim 3, wherein said pile foundation is provided so as to be movable relative to a guide frame vertically installed on said sheath pipe. The driftwood catcher according to any one of claims 1 to 5, characterized in that said projecting portion of said pile foundation is also fixed. A driftwood trap installed on the upstream side of an erosion control dam,
The driftwood catcher includes a closed cross-section forming member that forms a closed cross-section space, a filling material that fills the closed cross-section space, and an upright filling material that vertically penetrates the closed cross-section space. and a driftwood catching column member fixed to a driftwood catching body. 8. The driftwood trapping body according to claim 7, wherein a portion of said driftwood trapping column member protruding downward from said closed cross-sectional space is also fixed. The driftwood trap according to any one of claims 1 to 8, wherein the closed cross-section forming member is constructed by connecting a plurality of segments. The driftwood trapping body according to any one of claims 1 to 9, characterized in that said driftwood trapping column member is one or a plurality of pieces. The driftwood trap according to any one of claims 1 to 10, wherein said closed cross-section forming member is formed in a circular, oval, or rectangular shape when viewed two-dimensionally. The driftwood trap according to any one of claims 3 to 6 and 9 to 11, characterized in that said sheath tube is formed in the shape of a cylinder with a bottom. The driftwood catcher according to any one of claims 3 to 6 and 9 to 12, wherein the upper end of the sheath pipe is embedded substantially flush with the surface of the filling material. A construction method for a driftwood trap installed on the upstream side of an erosion control dam,
A step of erecting a closed cross-section forming member that forms a closed cross-section space at a predetermined location on the upstream side, and installing a pile foundation in a configuration that protrudes downward from the closed cross-section space;
a step of joining a driftwood capturing column member to the upper end of the pile foundation and standing up from the closed cross-sectional space;
filling a filling material into the closed cross-sectional space to fix the pile foundation and the driftwood capturing column member;
A construction method for a driftwood trap, characterized by comprising: A construction method for a driftwood trap installed on the upstream side of an erosion control dam,
A structure in which a closed cross-section forming member that forms a closed cross-section space is erected at a predetermined location on the upstream side, and a pile foundation provided with a bottomed cylindrical sheath pipe at the upper end protrudes downward from the closed cross-section space. A process of installing with
a step of filling the closed cross-sectional space with a filling material to fix the pile foundation and the sheath pipe, and inserting a driftwood capturing column member into the sheath pipe to raise it;
A construction method for a driftwood trap, characterized by comprising: A construction method for a driftwood trap installed on the upstream side of an erosion control dam,
a step of erecting a closed cross-section forming member that forms a closed cross-section space at a predetermined location on the upstream side, and installing a driftwood capturing column member so as to vertically penetrate the closed cross-section space;
filling the closed cross-sectional space with a filling material to fix the driftwood capturing column member;
A construction method for a driftwood trap, characterized by comprising: An installation structure for a driftwood trap installed on the upstream side of an erosion control dam,
The driftwood trapping work is composed of a plurality of driftwood traps according to any one of claims 1 to 13, and the plurality of driftwood traps are configured so that the distance between the driftwood trapping pillar members is 1/3 of the assumed maximum length of driftwood. An installation structure for a driftwood catching work, characterized in that it is spaced by about 1/2 and is installed in an appropriate arrangement for catching expected driftwood. 18. The installation structure of the driftwood trapping work according to claim 17, wherein the plurality of driftwood trapping bodies are spaced apart from each other in a substantially linear arrangement in the transverse direction of the river. 18. The installation structure of the driftwood trapping work according to claim 17, wherein the plurality of driftwood trapping bodies are spaced apart in an arrangement that forms a substantially fan shape or a substantially inverted fan shape. 18. The installation structure of the driftwood trapping work according to claim 17, wherein the plurality of driftwood trapping bodies are spaced apart in a meandering arrangement along the transverse direction of the river.

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