JPS6235685Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to foundation work for a movable weir used for weirs, etc. for intake of agricultural water.

In conventional foundation work for movable dams, as shown in Figure 1, the river bed surface on the downstream side of the dam location was protected with a concrete layer. Since the impact of falling water on this concrete layer was extremely large, the concrete layer had to be sufficiently thick, which resulted in extremely high construction costs. In addition, in order to prevent seepage flow (so-called piping phenomenon) from the river bed on the upstream side bypassing the area below the concrete weir and reaching the river bed on the downstream side, A=U+V+X+Y+Z≧C ₂ H (where H is the head and C ₂ is a coefficient determined depending on the type of ground, and the penetration path length A was set so as to satisfy the following condition: C ₂ =9 to 12. In order to satisfy this condition, the length V of the concrete weir in the upstream and downstream directions increases, the amount of concrete used increases, and as a result, a rise in construction costs is unavoidable. Furthermore, in riverbeds with a large head and a large amount of water, the riverbed surface may be eroded by the strong water flowing above it, and a large amount of concrete was required to prevent this erosion.

The present invention relates to the foundation work of a movable weir that overcomes these difficulties, and in the foundation work of a movable weir such as a flexible membrane weir, the entire area in the river width direction reaching the outer part of the riverbed and slopes on both banks. It consists of an impermeable wall that is driven vertically into the ground from the fixed part of the movable weir, and a flexible membrane that extends downstream from the fixed part of the movable weir and covers the river bed surface. Its purpose is to provide a protected river bed surface with a simple structure and at low cost.

As mentioned above, the present invention is designed to protect the river bed from the fixed part of the movable weir over the entire width of the river, reaching the outer part of the slope on both sides of the river bed, at least enough to protect the river bed from the impact of overflowing water. Since a flexible membrane is provided that extends in the downstream direction and covers the riverbed surface, the riverbed surface is protected by the flexible membrane, eliminating the need for a large amount of concrete, making construction easy and significantly lower in cost. Become. In addition, with conventional movable weirs, it was necessary to install river bed concrete with a certain seepage path length on the downstream side, which required a large amount of concrete, but with this invention, the watertight sheet piles can block the seepage water flow. Therefore, from this point of view as well, a large amount of concrete is not required.

Therefore, construction is easy and only a small amount of concrete is required, so it is possible to significantly reduce construction costs as a whole.

Hereinafter, an embodiment of the present invention illustrated in FIGS. 2 to 4 will be described.

Bottom surface 11 of river bed 10 and slopes 12 on both sides thereof
A sheet pile 1 of a predetermined length is driven along the vertical plane over the entire width direction reaching the outer part of the sheet pile 1, and an anchor concrete block 2 is attached to the top of the watertight sheet pile 1.
It was poured in Ikkyu to form an impermeable wall.

In addition, the anchor concrete block 2
On the upper surface, a rubber sheet 6 which is a flexible membrane having a constant width and a rubber weir 8 which is a type of movable weir are stacked one after another over the riverbed bottom surface 11 and the riverbed slope surface 12 in contact with the upper surface of the rubber sheet 6. It is laid in a state where it is installed.

The rubber sheet 6 and rubber dam 8 described above are made of cotton,
The main component is a belt-shaped rubber sheet integrally molded with one or more belt-shaped woven fabrics made of synthetic fibers or a reinforcing layer made of fiber cords. The rubber weir 8 is folded in half and stacked on top of each other,
Anchor bolts 3, embedded metal fittings 4, holding metal fittings 5 and nuts 9 are placed on the upper surface of the rubber sheet 6 and buried in the anchor concrete block 2 so that the folded free end side edge is located on the upstream side.
It is firmly fixed to the anchor concrete block 2 in an air and watertight manner.

It goes without saying that the rubber sheet 6 may be a pure rubber sheet without reinforcing fibers.

Since the embodiment shown in FIGS. 2 to 4 is constructed as described above, the rubber weir 8 in the inflated state
The water flow that overflows the riverbed does not come into direct contact with the bottom of the riverbed.
It flows downstream along the surface of the rubber sheet 6. Therefore, even if the weir height H is high to some extent and the water force is strong, the riverbed bottom surface 11 and the riverbed slope surface 12 are not scoured, so riverbed concrete on the downstream side of the rubber weir 8 is unnecessary.

In addition, watertight sheet piles 1 of a certain length are driven under the anchor concrete block 2 to the width of the riverbed 10, which can prevent seepage water flow and create a shorter seepage path compared to conventional movable weirs. It can be long and eliminates the need for large amounts of concrete.

In this way, there is no need for concrete at the bottom of the riverbed or concrete for increasing the length of the seepage path, and there is no need to excavate earth and sand, and the amount of concrete required is extremely small, resulting in low construction costs and a short period of time. Construction will be possible.

Furthermore, by deflating and collapsing the inflated rubber weir 8, the river can be returned to its natural state.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional side view of a conventional flexible membrane, Fig. 2 is a plan view illustrating an embodiment of the foundation work of a flexible membrane weir according to the present invention, and Fig. 3 is a cross-sectional side view of a conventional flexible membrane. 4 is an enlarged cross-sectional side view of the main part of FIG. 2. 1...Watertight sheet pile (waterproof wall), 2...Anchor
Concrete block (water-shielding wall), 3... Anchor bolt, 4... Embedded metal fitting, 5... Holding metal fitting, 6... Rubber sheet (flexible membrane), 7... Rubber sheet upstream end, 8... ...Rubber weir, 9...Natsuto,
10...Riverbed, 11...Riverbed bottom, 12...Riverbed slope.

Claims (1)

[Scope of utility model registration request] In the foundation work of a movable weir such as a flexible membrane weir, a shield is installed perpendicularly into the ground from the fixed part of the movable weir over the entire width of the river, reaching the outer part of the slope of the riverbed and both banks. A movable weir comprising a water wall and a flexible membrane extending downstream from a fixed part of the movable weir by at least a length sufficient to protect the riverbed from the impact of overflowing water and covering the riverbed surface. Foundation work.