JPH0376916A - Permeable checkdam - Google Patents

Abstract

PURPOSE:To permit large stones to be stored exactly on the upstream side of a structure during a great flood by simple construction work in which wire ropes are laid vertically and horizontally between steel tubular columns erected at almost equal intervals on a river bed, etc. CONSTITUTION:Steel tubular columns 1a - 1d are erected at almost equal intervals by crossing them to the flowing direction of sand-stone avalanche on a river bed. 7. Wire ropes 4a - 4c and 5 or reinforced fibrous ropes are laid vertically and horizontally between the columns 1a - 1d. During small or medium flood, sand-stone avalanche is directed to flow through the apertures between the columns 1a - 1d and the wire 4a - 4c and 5. During great flood, large stones greater than the apertures are stored on the upstream side of a structure and small sand and gravel and water are directed to flow to the downstream side through the large stones.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a permeable erosion control dam for controlling debris flows occurring on the slopes of mountain streams, streams, etc. in mountainous areas.

[Conventional technology] Sabo dams that regulate debris flows that occur on the slopes of mountain streams and streams in mountainous areas are functionally divided into impervious type erosion control dams and permeable type erosion control dams from the viewpoint of storing or permeating the flowed debris during normal times. It is classified as a dam.

Although impermeable sabo dams are permeable, their sand storage space decreases when water flows out during normal times, making it difficult to maintain sufficient sand storage space when a debris flow occurs.

On the other hand, permeable erosion control dams are used as equipment to store and reduce the force of debris flows, and to separate water and sediment.
Almost no sediment is stored during normal flooding, and the storage space can be maintained until a major flood occurs. For this reason, by making the opening of the structure wide enough so that it will not be closed by sand and gravel during small to medium floods, fine sand and gravel that normally flows down will be allowed to pass through, but during large floods, the opening will be blocked by flowing boulders.
Efforts are being made to prevent debris from flowing out.

Such permeable erosion control dams are constructed by, for example, constructing a large structure consisting of a main material made of steel pipes and a retaining material, which are installed on the riverbed at predetermined intervals parallel to and orthogonal to the direction of debris flow. A structure in which multiple pieces are installed (such as Japanese Utility Model Application Publication No. 51-58536, Japanese Patent Application Publication No. 57-29717, Japanese Utility Model Application Publication No. 61-188833, etc.), or a structure with a three-dimensional frame such as a jungle gym, can be installed under the influence of a debris flow. Multiple units installed on the riverbed at predetermined intervals perpendicular to the direction
15520, etc.), and furthermore, a structure in which steel arm members and tie members are installed in multiple stages and connected to the main pillar is installed on the river bed with the arch members facing upstream and at intervals that only block boulders. There is one with a stand installed (Japanese Unexamined Patent Publication No. 1-94104).

However, the above-mentioned permeable erosion control dams have a complicated structure and are expensive to manufacture, and in addition, the construction period is long because many structures are installed on the riverbed, etc., and they cannot be used for urgent construction. There is a problem.

Therefore, in order to solve this problem, as shown in Figure 3, anchors 3a and 3b are installed facing the mountainside 8 on both sides of the riverbed 7, etc., and a hanging rope 9 is stretched between them. ,
A transparent sand control dam in which a net 1O made of wire or the like is suspended from the hanging rope 9 has been proposed and put into practice.

[Problems to be Solved by the Invention] An erosion control dam using the net 10 made of wire or the like as described above has a simple structure and is easy to manufacture, is easy to install on site, and can be used for emergency construction. However, there are the following problems.

(1) The suspension rope 9 is supported by anchors 3a and 3b provided on the mountainside, but the anchors 3a and 3b
Anchor 3a is subjected to a large amount of force, so the structure must be able to withstand this, and the construction environment is also poor.
, Bb construction is extremely troublesome.

(2) When the distance between the mountainsides 8 and 8 is long, it is very troublesome to extend the suspension rope 9 to which the net lO is attached. Furthermore, during a major flood or the like, excessive force is applied to the hanging rope 9, so that the hanging rope 9 may be severed.

(3) Since both sides and the lower end of the net 10 are free, it may not be possible to reliably store huge stones.

The present invention was made to solve the above-mentioned problems, and its purpose is to obtain a permeable sabo dam using wire, etc., which is easy to construct, strong, and capable of reliably retaining debris flows in the event of a major flood. It is.

[Means for Solving the Problems] In the permeable erosion control dam according to the present invention, a plurality of steel pipe columns are erected on a river bed or the like at approximately equal intervals perpendicular to the direction of debris flow, and there are gaps between the steel pipe columns. It consists of multiple wire ropes or reinforcing fiber lobes stretched in the horizontal and vertical directions.

[Operation: During small to medium floods, debris flow flows through the gap between the steel pipe pillars and the wire rope, and the debris flow is not stored.

During a major flood, boulders larger than the gaps are stored upstream of the structure, and water and fine gravel flow downstream from between the boulders.

[Embodiment] FIG. 1 is a front view of an embodiment of the present invention viewed from the upstream side, and FIG. 2 is a plan view thereof. In the figure, La, Lb.

lc and ld are steel pipe columns (hereinafter referred to as steel pipe columns) erected on the river bed 7 at approximately equal intervals using concrete foundations, pile foundations, etc., orthogonal to the flowing direction of the debris flow, and in the example, steel pipe columns 1a are used. ~ld has an outer diameter of 1200 inches and a wall thickness of 14 m.
The length (height) H above the river bed 7 was set to 8500 m. Also each steel pipe pillar! The distances L, L, and L between the centers of a to 1d are each 5000 mm
And so.

23 2a, 2b are anchors 3a, 3 installed on the riverbed 7
A support cable is stretched in the horizontal direction between the support rope 1b and the steel pipe columns 1a and 1d on both sides, and in the example, the angle θ is 45''.

Note that these support ropes 2a and 2b may be strung between anchors provided on the upstream side, as shown by broken lines in FIG.
Further, depending on the topography, it may be placed between anchors provided on the mountainsides on both sides of the riverbed 7.

4a, 4b, and 4c are wire ropes stretched horizontally on the upstream side between the steel pipe columns 1a and ld, and each wire rope 4
Both ends of a to 4d are wound around the steel pipe columns 1a and ld and fixed with fixtures 6, and the middle parts are fixed to the steel pipe columns 1b and Ic with a fixture 8a.

5 is a wire rope 4a between each steel pipe column 1a-Ld.
, 4a, and are fixed to the wire ropes 4a, 4b, 4c by welding or fixing devices, respectively, and these steel pipe columns 1a to 1d.

The wire ropes 4a to 4c and the wire rope 5 constitute a net-like structure.

In the embodiment, the wire ropes 4a to 4c, 5 have an outer diameter of 50 mm.
~58 mm (No. 5 to 6) wire ropes are used, wire rope 4a is stretched 250 mm below the top of steel pipe columns 1a-1d, wire rope 4c is stretched 250 mm above river bed 7, and wire rope 4b is stretched between both wire ropes. 4a, 4c (distance h, h between both wire ropes 4a, 4a)
Two strips were strung to a length of 3000 mm each. In addition, steel pipe column 1a-1
d and the distance g between the wire rope 5 and each wire rope 5 was about 950 degrees.

The permeable sabo dam according to the present invention configured as described above,
During small and medium-sized floods, the debris flow that flowed down the steel pipe column 1a-
The sand does not flow out from the gap between the wire 1d and the wire 5 and accumulate on the upstream side of the structure, ensuring a sufficient storage space.

When a debris flow flows down due to a major flood, water and small sand and gravel flow downstream from the gaps in the structures, but megaliths 11 larger than the gaps cannot flow out, so they are stored upstream of the structures as shown in Figure 2. Ru.

Note that some of the water and fine gravel flows downstream through the gaps between the boulders 11.

In this way, water and gravel are separated, and the energy of falling debris is transferred between the steel pipe column fa-1d and the wire ropes 4a to 4.
The power is reduced by C15 and stored on the upstream side of the structure.

In the above description, the wire ropes 4a to 4c and 5 are stretched between the steel pipe columns 1a to 1d to form a net shape, but reinforcing fiber lobes may be used instead of the wire ropes.

Furthermore, although the quantities, dimensions, etc. of the members constituting the present invention are shown as examples, the present invention is not limited thereto.
It can be changed as appropriate depending on the situation at the site.

[Effects of the Invention] As is clear from the above description, the present invention involves erecting a plurality of steel pipe columns at approximately equal intervals on a riverbed, etc., and horizontally extending a plurality of wire ropes or reinforced fiber ropes between these steel pipe columns. Since the sabo dam is constructed by stretching the sand in both the horizontal and vertical directions, the following remarkable effects can be obtained.

(1) The structure is simple and construction is easy, so the construction period can be shortened.
It can also handle emergency construction.

(2) Since a plurality of steel pipe columns are provided, there is no risk of wire ropes etc. being cut even if a large load is applied due to accumulation of earth and sand.

(3) Since the steel pipe columns are erected on the riverbed, etc., and wire ropes etc. are stretched near the floor surface of the riverbed and fixed to the steel pipe columns, megaliths can be stored reliably.

(4) Anchors mainly support steel pipe columns, and are often installed in relatively good environments.
It does not require large-scale construction and is easy to construct.

(5) Wire ropes etc. can be easily replaced.

[Brief explanation of drawings]

FIG. 1 is a front view of an embodiment of the present invention viewed from the upstream side, FIG. 2 is a plan view thereof, and FIG. 3 is a schematic diagram showing an example of a conventional permeable erosion control dam. la~ld: Steel pipe column, 2a, 2b: Support cable, 4a~4
c, 5: wire rope, 6, 8a: fixture, 7: river bed. Figure 3

Claims (1)

[Claims] Multiple steel pipe columns were erected on the riverbed, etc., at approximately equal intervals perpendicular to the flowing direction of the debris flow, and multiple wire ropes or reinforced fiber ropes were strung between these steel pipe columns in the horizontal and vertical directions, respectively. This is a permeable erosion control dam.