JPS63247414A - Group of piles type open dam - Google Patents

Abstract

PURPOSE:To form a check dam at low cost by arranging a number of steel tubular piles in the widthwise direction of river bed and also in the flowing direction of river water. CONSTITUTION:A number of steel tubular piles 1 are driven with a sufficient penetration depth L in the widthwise direction of river bed and also in the flowing direction of river water. The heads of the piles 1 are connected with a supporter 2 to form a flat truss structure wholly, and a concrete layer 3 for preventing scouring is formed on the river bed. An open dam to prevent the occurrence of damage by run-off of soil during a flood can thus be constructed at low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement of an oven dam structure for preventing damage caused by debris flows during floods.

(Prior art and its problems) A debris flow refers to a case in which an abnormally large amount of sediment (flows out) than is normally transported by a river flow, the flow distance is sufficiently longer than that of a collapse, and the movement speed is faster than that of a landslide. , a flow of sediment that flows down as a combination of water and sand, often containing boulders.Therefore, the damage caused by debris flows during floods is enormous. dams such as slit-shaped dams and lattice frame dams are designed to trap stones and gravels in debris flows and reduce the destructive energy of debris flows through the screen effect, thereby minimizing damage to downstream areas. Various oven dams have been proposed.

However, in the conventional oven dam structure, as shown in Fig. 3, the riverbed RB is excavated into a predetermined shape to form a concrete foundation CB, and the concrete foundation icB is
Since it is common to embed and fix the support column P inside the structure via an anchor AC, there is a drawback that the installation is limited by the topography and the construction cost is enormous.

(Problems to be Solved) The present invention is an open system that is not only applicable to any type of installation terrain, but also allows the selection of the stone gravel trapping size according to the cobblestone particle size at the installation location at a low construction cost. The task is to provide a dam.

(Means for Solving the Problems) The present invention provides group piles by fully embedding steel pipe piles directly into the river bed according to the size of boulders at the installation location, instead of the conventional structures such as slit dams and lattice frame dams. He discovered that by arranging the dams in the same manner and laying a concrete layer against the riverbed to prevent scour, it was possible to install an open dam at a low construction cost and without being restricted by topography. The gist of this is that ``Multiple steel pipe piles (1) with sufficient penetration length into the riverbed RB are arranged at regular intervals in the river width direction, and multiple steel pipe piles (1)... are arranged at regular intervals in the river width direction. While arranging it over stages,
This type of oven dam consists of a concrete layer (3) to prevent scouring on the riverbed RB.

Hereinafter, the present invention will be explained in detail based on the accompanying drawings.

(Example) FIG. 1 is a schematic view of a vertical pile type oven dam according to the present invention as seen from the downstream side, and FIG. 2 is a plan view thereof.

In the drawing, (1) is a steel pipe pile, which is driven into the riverbed RB with sufficient penetration length, and the head is connected by a support frame (2) as shown in Figure 2, making the whole a planar truss. A concrete layer (3) will be laid on the riverbed RB to prevent scouring.

The spacing of the steel pipe piles (1) in the river width direction is adjusted according to the size of boulders at the location where the open dam is installed, and the distance between the steel pipe piles (1) is adjusted according to the particle size of the largest boulder in the debris flow. ),
(1) It is preferable to set the effective interval W between 1.5 and 2.0D.

Further, although it is necessary to arrange piles in multiple stages in the river flow direction to form a group of piles, it is not necessary that the front row spacing and the back row spacing be equal, and the rear row spacing may be narrower than the front row spacing.

The riverbed RB where the open dam will be installed is the downstream section of a mountain stream where debris flows are likely to occur, but if it is necessary to selectively store debris in the river as a whole, vertical sections for megalith storage will be installed sequentially from the upstream to the midstream of the debris flow downstream area. By arranging multiple pile-type open dams, vertical pile-type oven dams for large-diameter boulder storage, and vertical pile-type open dams for medium-diameter boulder storage, they can respond to large floods and small to medium-sized floods, and effectively utilize the destructive energy of debris flows. It is possible to capture only predetermined boulders while reducing their force.

(Operations and Effects of the Invention) As is clear from the above explanation, according to the present invention, stones in a debris flow are selectively captured by group piles, and water and earth and sand pass between vertical piles and flow downstream. , the destructive energy of debris flows can be effectively reduced, and damage caused by debris flows during floods can be prevented without interfering with river functions.

In addition, multiple steel pipe piles (1) with sufficient penetration length into the riverbed RB were installed in the river width direction so as not to be subject to topographical restrictions unlike conventional structures such as slit dams and lattice frame dams. Since the dams are buried at regular intervals, open dams can be installed without being restricted by mountain stream topography.

Furthermore, although the group piles have a simple structure of being embedded in the riverbed RB, vertical pile type open dams can be constructed using an inexpensive structure of connecting the heads of all steel pipe piles (Tl) to form a planar structure. It is possible to maintain sufficient structural strength. Therefore, it is possible to form an open dam at a lower construction cost than before, making it very useful as an erosion control dam.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a group pile type oven dam of the present invention as seen from the downstream direction, FIG. 2 is a plan view thereof, and FIG. 3 is a schematic diagram showing the installation form of a conventional open dam. fi+...Steel pipe pile, (2)...Support frame, (3)...Concrete layer for scour prevention

Claims (1)

[Scope of Claims] [1] A plurality of steel pipe piles (1) having a sufficient penetration length L into the riverbed RB are arranged at regular intervals in the river width direction, and a plurality of steel pipe piles (1) are arranged at regular intervals in the river width direction. Concrete layer (3) to prevent scouring will be installed on the river bed RB.
A group pile type open dam characterized by the construction of piles. [2] The group pile type open dam according to the above item [1], in which the heads of all-steel pipe piles (1) are connected to form a planar truss structure.