JPH0610330A - Permeation type weir made of steel - Google Patents

Abstract

PURPOSE:To prevent movement of an aqueduct after an avalanche of sand and stone is captured by a method wherein the position of a beam between the columns of the central part of a permeation part of which a weir is composed is lowered to a level lower than that of a beam between other columns and by a distance shorter than a distance between the columns 1. CONSTITUTION:The position of a steel pipe beam 2 between steel pipe columns 1 at the central part of a permeation part of which a permeation type weir is composed is lowered to a level lower than that of a beam 2 between other columns 1. The position of the steel pipe beam 2 at a topmost stage between the steel pipes column 1 is gradually raised to a level higher than the position of the beam 2 between the columns 1 at the central part of the permeation part from the central part toward both sides. And the beam 2 is arranged by a distance shorter than a distance between the columns 1 below the beam 2 at a topmost stage between the columns 1. This constitution pushes out a larger quantity of stone gravels, accumulated at the beam 2 at the central part, of relatively smaller stone gravels subsequently accumulated on stone gravels having a maximum size captured by the weir, causes centralization of flowing water to a central part, and ensures an aqueduct.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a debris flow control dam, and more particularly, to a transmission steel dam which allows water to pass through in the central portion of the water passage even after trapping debris flow.

[0002]

2. Description of the Related Art Transmission steel dams are currently used as a measure against debris flow. In this steel dam, as shown in Fig. 3 (a), a grid-shaped steel dam having a structure in which steel pipe columns 1 and steel pipe beams 2 are combined in a three-dimensional lattice shape, and as shown in Fig. 3 (b), steel pipes are used. There is a B type slit dam having a structure in which a pillar 1 and a steel pipe beam 2 are combined. The feature of these dams is that they have the function of capturing all or part of the debris flow by utilizing the feature that megaliths concentrate at the tip when the debris flow flows down, as shown in FIG. Is.

Regarding the debris flow capturing effect, attention is paid to the gravel gravel group that will constitute the tip portion 12 of the debris flow, and the maximum diameter of the gravel gravel is 10
It is known that if the net spacing of the pillars is less than 1.5 times, then the subsequent debris flow will be completely captured, and if it is 2.0 times, the gravel at the tip will be captured. Also, if the net spacing between columns and beams is increased by 2.0 times, the same capture as 1.5 times the net spacing between columns is obtained. The factor that exerts this function is the net spacing 11 between the steel pipe columns 1 forming the dam structure, which is located upstream and is perpendicular to the river axis. Therefore, at present, the net spacing 11 between the pillars in the direction perpendicular to the river axis, which constitutes this type of dam, is in the range of 1.5 to 2.0 times the maximum gravel diameter.

[0004]

Generally, in a permeable steel dam, the permeable portion is made of steel and the non-permeable portion is made of concrete. The central part of the transparent part is installed near the center of the river axis. However, due to the flow characteristics of the debris flow, gravel is deposited in the central part of the permeation part, so it has been confirmed by research that the water supply moves to the end of the permeation part after the dam has captured the debris flow. When the water supply moves to the end of the permeable part, the hillside on the water supply side is eroded, which may cause a secondary disaster.

The present invention has been made in order to solve the above problems, and regulates the position of the beam between the columns forming the steel dam, so that the waterworks can be performed even after the dam has captured the debris flow. It is an object of the present invention to provide a transmission steel dam that does not move.

[0006]

In a transmission type steel dam, only the most upstream column net spacing has a debris trapping effect, but in the present invention, a beam positioned as a structural member is positively used as a functional member. According to the first aspect of the present invention, in a transmission type steel dam, the position of the beam between the pillars in the central part of the transparent portion forming the dam is set to be greater than the position of the beam between the other pillars. It is a permeation type steel dam that is lower than the gap.

The second aspect of the present invention is that, in a transmission type steel dam, the position of the uppermost beam between the columns of the transmission part forming the dam is
The beam is positioned higher than the position of the beam between the pillars in the central part of the transparent part, going from the central part to both sides, and the beams are arranged below the uppermost beam between the pillars at intervals shorter than the column interval. It is a transmissive steel dam.

[0008]

Operation: The gravel at the tip of the debris flow is captured by the column spacing, but the trapped gravel may be washed away by the subsequent flow. However, investigations have confirmed that when beams are present, the gravel trapped below the beams remains trapped in the dam.

By utilizing this phenomenon, the position of the beam between the pillars in the central part of the transmission part forming the dam is made lower than the position of the beam between the other pillars by a distance between the pillars. The gravel trapped below the beam is restrained, and the relatively small gravel flowing above the beam overflows. Therefore, the gravel bound by the beam has the lowest central portion, and as a result, the water supply is secured here.

If the positions of the beams between the columns are made higher than the positions of the beams between the columns in the central part of the transparent portion as they go from the central part to both sides, the stones and stones bound by the beams will go to both sides. The height of the gravel becomes V-shaped. Therefore, it becomes easy to collect the running water in the central part, and the water supply does not move from the central part.

However, if the positions of the beams between the pillars are made higher than the positions of the beams between the pillars in the central portion of the transparent portion in order from the central portion to both sides, the beam between the pillars in the central portion will be increased. The position is the lowest, and it's the easiest place to hold gravel. That is, until the gravel is deposited up to the beam between the pillars and becomes V-shaped, the gravel is piled up in the central part, and the running water is divided into two. Therefore, by arranging the beams below the uppermost beam between the columns at an interval shorter than the column interval, it is possible to prevent gravel from accumulating in the central portion.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 (a) is a diagram of a transmission type steel dam in which the position of the beam between the pillars in the central portion of the transparent portion of the present invention is lower than the position of the beam between other pillars and lower than the distance between the pillars. In Fig. 1 (b), the position of the uppermost beam between columns is higher than the position of the beam between columns in the central part of the transmissive part from the central part to both sides, and It is a figure of the permeation | transmission type steel dam which has arrange | positioned the beam with the space | interval shorter than the space | interval of a pillar under the beam of the highest step in between. In the figure, 1 is a steel pipe column, 2 is a steel pipe beam, 3 is a river axis,
4 shows the beam pure intervals, respectively. The beam net spacing 4 is shorter than the column net spacing.

FIG. 2 schematically shows a process in which gravel is deposited on the permeable steel dam shown in FIG. 1 (a). An embodiment will be described below with reference to FIG.

The function of capturing the debris flow itself is determined by the column net spacing. When the tip of the debris flow reaches the dam, the pillar member captures the gravel 5 having the maximum gravel diameter, as shown in Fig. 2 (a). At this time, in the initial stage of the trapped state, there is no difference in the trapped state between the central part and the end of the permeation part of the dam. After that, the small and medium gravel contained in the subsequent flow fills the gap of the gravel 5 captured by the pillar.

When it is filled up, the subsequent relatively small gravel 6 tries to overflow over it, as shown in FIG. 2 (b).
Increase the pile height. Then, as shown in FIG. 2 (C), the water pressure on the back surface of the gravel accumulated by the water surface 8 being dammed up increases.

The stone gravel 6 which cannot endure water pressure is shown in FIG.
As shown in (d), it is pushed out from the pillar. At this time, the gravel 6 deposited below the beam is restrained by the beam member, and only the gravel 6 deposited above the beam is pushed out. Further, since the beam in the central portion is arranged low, a large amount of gravel 6 is extruded, and when it is extruded, running water concentrates there. Therefore, even after passing the debris flow, the water supply 7 is secured in the central part of the dam penetration part, and the river axis does not move.

[0017]

As described above, according to the present invention, in a transmission type steel dam, the position of the beam between the pillars in the central part of the transmission part forming the dam is
It is lower than the position of the beam between other columns, and the interval between beams (beam net interval) is shorter than the column interval, and the position of the uppermost beam between columns is set between the columns at the center of the transmission part. A transmission type steel dam, in which the beams are sequentially raised from the center to both sides from the position of the beams, and the beams are arranged below the uppermost beam between the columns at intervals shorter than the column intervals. According to this transmission type steel dam, the amount of stones and gravel accumulated in the central part of the permeation part is small, the water supply is secured in the central part of the permeation part of the dam after the debris flow and the river axis does not move. Therefore, the water supply in the central part of the dam permeation part does not move to the end of the permeation part, the water supply does not erode the hillside, and there is no risk of a secondary disaster.

[Brief description of drawings]

FIG. 1 is an explanatory view of a transmission type steel dam according to the present invention.

FIG. 2 is a view schematically showing a process in which stones and gravel are deposited on the transmission steel dam of the present invention.

FIG. 3 is a diagram showing an example of a conventional transmission steel dam.

FIG. 4 is a diagram illustrating a function of a transmission steel dam to capture a debris flow.

[Explanation of symbols]

1 ... Steel tube column, 2 ... Steel tube beam, 3 ... River axis, 4 ... Net beam spacing,
5 ... Stone gravel, 6 ... Stone gravel, 7 ... Water supply, 8 ... Water surface, 10 ... Maximum diameter of stone gravel, 11 ... Net spacing of columns, 12 ... Tip of debris flow.

Claims (2)

[Claims] 1. In a transmissive steel dam, the position of the beam between the pillars in the central part of the transparent part constituting the dam is set lower than the position of the beam between other pillars. A permeation type steel dam. 2. In the transmission type steel dam, the position of the uppermost beam between the columns of the transmission part forming the dam is set from the central portion rather than the position of the beam between the columns of the central portion of the transmission part. A permeation type steel dam, wherein the beams are gradually increased toward both sides, and the beams are arranged below the uppermost beam between the columns at intervals shorter than the column intervals.