JPS63134706A - Gravel-conducting pipe having truncated conical coiling wall - Google Patents

Abstract

PURPOSE:To enable gravels on the river-bed to be exactly discharged, by providing the river-bed near a dam backwater end, with a slit-formed inlet, and by communicating pipe shell generating spiral vortex in the internal section, with the inlet. CONSTITUTION:The river-bed GL near a dam backwater end is provided with a pipe shell 2 orthogonal to the river-bed GL, and a slit-formed inlet 3 opening from the pipe shell 2 toward the upper stream. Besides, a coiling wall 1 keeping a proper level, communicating with the inlet 3, is formed. When a water level comes to a gravel flow water-level SWL or higher with flood or the like, then pipe-internal flow is generated at an overflow weir section 8 by a siphon action. Then, through the inlet 3, water and gravels are conducted into the pipe shell 3, and by pipe-internal spiral vortex flowing through the pipe shell 2, the gravels are discharged.

Description

[Detailed description of the invention] (a) Industrial application field This invention is a method for removing sand bundles that are laid diagonally across the riverbed near the end of a dam backwater to introduce a density flow mixed with sediment at the time of water outflow and then flowed out of the river. By forming the tube cavity of the pipe with a truncated conical wall, it corresponds to the flow rate of each part of the density flow introduced from the entire length of the inlet, and by cumulatively increasing the flow area of each part of the pipe, flow resistance is suppressed and smooth flow is achieved. In addition, the sand is connected to an inlet flow pipe having a truncated conical enclosing wall so as to assist the upward flow of the solids in the pipe.

(B) Conventional technology Conventionally, this type of sand drain remover generally has a vertically elongated slit-shaped inlet in the pipe wall, and is connected to the downstream end of the pipe and is connected to a pressure pipe such as a passage or a siphon gate. Unlike the conventional cylindrical discharge pipe, which is a kind of open pipe and also an inlet to a delivery outlet, each part of the slit-shaped inlet The filling of each part of the pipe, which has to correspond to the cross-sectional area of accumulated water flowing from the pipe, is large in the upstream part of the pipe, gradually decreases as it flows downstream, and becomes smaller in the downstream part, and the flow resistance in the pipe increases, taking into account the flow characteristics of solids. This also makes it difficult to introduce as uniform a density flow as possible from the riverbed surface that is in contact with the entire length of the inlet, resulting in blockage due to the obstruction of smooth flow of solids such as sand and gravel in the pipe. This is because it is the cause of the problem, and there are actual cases where the pipes become clogged and buried and become inoperable within a few years after installation.

(c) Problems to be Solved by the Invention This invention reduces the flow resistance in the pipe by using a sand and gravel removal pipe having a truncated cone-shaped enclosing wall, so that sand supports the uplift and flow of solid substances, and is effective at times of high water flow. The purpose of the present invention is to obtain an over-sand ↑ introduction flow conveying pipe having a truncated conical entrainment wall configured to smoothly and efficiently introduce the sediment-mixed density flow from the river bed surface and transport it to the outside of the river.

(d) Means for Solving the Problems This invention will be explained based on the drawings. The outer peripheral edge of the winding wall 1 also serves as the upper edge of the inlet 3 which opens toward the upstream side,
They are located on an extension line that connects the transverse center point 0 of the pipe side 2 at right angles to the riverbed surface GL, and are arranged at appropriate height intervals in consideration of the size of solid materials such as sand and gravel, as well as the amount of inflow. Coupled with one entrainment wall, the filling of the tube side 2 gradually expands downstream in response to the cumulative inflow cross-sectional area of the slit-shaped inlet 3 formed over the entire length of the tube side 2, and the entrainment seen in cross section. The mutual spacing between the walls 1 is also appropriately widened toward the center to prevent solids from getting stuck between the walls, and to prevent the solids from sinking to the bottom of the pipe side 2. In order to provide as much support as possible, the peripheral end of the winding wall 1 continues to wind up in a truncated conical shape until near the bottom of the pipe side 2, and the upstream end surface of the pipe cavity 2 is connected to the right bank which also serves as the pipe foundation 4. It is pivotally attached to the retaining wall 5, so that the lower surface of the inlet 3 and the river bed surface GL span the entire surface and are in contact with each other, and as a result, due to the conical tube shape, a slope is created in the pipe with respect to the river bed surface GL, and the pipe side 2. In order to encourage the internal flow force, the river channel is oriented downstream at an appropriate angle to the stream line of the river, diagonally crossed, and pipe foundations 4 are appropriately placed along the way. After excavating both banks and the riverbed, the left bank retaining wall 6, which also serves as a retaining wall 6, is constructed by pouring reinforced concrete in-situ, etc. so as to connect it to a sand and gravel flow restriction road or a siphon gate.

(E) Function The gravel inlet flow pipe with the truncated conical enclosing wall 1 constructed as described above is connected to Kanei when the river water level is at the normal water level LWL which does not reach the gravel flow water level SWL. The rising overflow weir section 8 of Sai 7 On Gate is weird, and its airway hole 7 is in communication with the atmosphere, so the flow in the pipe stops, and the water level HW at high water levels exceeds the sand and gravel flow water level SWL due to increased water due to floods etc.
In the case of L, etc., the airway hole 7 is closed due to the rise of the river water, and the flow within the pipe is performed by the siphon effect, and the river downstream density flow containing sediment such as bed bed and some floating sand is brought into contact with the river bed surface GL at the inlet 3. It is introduced by dropping into W Cave 2 and flowing out of the river one by one, and the solid matter such as sediment contained in the density flow has poor adaptability unlike water, and the flow characteristics of solid matter such as specific gravity, shape, etc. The flow rate of each solid varies depending on the size, the solids, the pipe wall, etc., and as mentioned in the previous section, the pipe side 2 is connected to the relevant upper deck where the vertically elongated inlet 3 is in contact with the riverbed surface GL. It is a kind of open pipe, unlike pressure pipes such as siphon-on gates, which are used for siphon-on gates, and at the same time, it should also be regarded as an introduction port to siphon-on gates, etc., and it is a type of open pipe that can be used to prevent soil and sand mixtures having various predispositions as described above. Pipe side 2 of density flow
Internal flow is different from the case of only water, and although it is extremely complicated, a truncated conical winding wall with a vertically elongated inlet 3 opened on the pipe side due to the shape restriction essential for introducing density flow from the river bed surface GL. Each part of the pipe side 2 formed by the pipe 1 has a filling volume corresponding to the cumulative water cross-sectional area of the inlet 3, so that the flow is caused by flow modulation caused by overfilling or underfilling as seen in conventional cylindrical pipes. In addition to suppressing the clogging of solids, the fluid pressure from the extended engulfment !1 and the entire length of the inlet 3 near the bottom of the tube cavity 2 causes the streamlines to form a spiral engulfment shape on the tube side. The agitation flow flowing down inside the pipe tube 2 assists the uplifting flow of solids that are about to settle and stagnate at the bottom of the pipe cavity 2. In addition to the above, the river bed surface GL and the inlet port 3 are installed adjacent to each other over the entire length. The flow force is increased by the hydraulic gradient caused by the conical pipe on the pipe side 2, and the effect is more than compensated for various losses due to the complicated walls of the pipe side 2.

(f) Effects of the Invention As explained above, the present invention provides a truncated conical winding wall to fill each part of the tube cavity 2 corresponding to the cumulative water cross-sectional area of the inlet 3 over the entire length of the tube side 2. By forming the two walls on the tube side by the wall 1, it is possible to suppress flow obstruction or blockage caused by solids in the tube side 2, and also to assist the lifting and flow of the solids by the entrainment wall 1. : An increase in the flow force based on the hydraulic gradient caused by the installation of the cave 2, and from the inlet 3 spanning the entire length: A high density flow with an average density of about 6 is introduced to the inlet 3.
and the tube body 2 smoothly and efficiently flow the density flow, that is, the sand ξi
This has the effect of allowing the introduction and distribution of such materials.

[Brief explanation of the drawing]

Fig. 1 shows the structure and installation state of the sand introduction pipe with the truncated circular fiber enclosing wall according to the present invention; Fig. 1 is a longitudinal cross-sectional view;
FIG. 2 is an AB cross-sectional view in FIG. 1.

Claims (1)

[Claims] 1. During high water flow, efficiently introduce the density flow mixed with sand and gravel from the river bed surface (GL) near the end of the dam backwater, and smoothly move it out of the river by responding as much as possible to the cumulative water cross-sectional area from the slit-shaped inlet (3). It has a truncated conical winding wall characterized by comprising a truncated conical winding wall (1) with a tube cavity (2) that spans all parts of the entire length and holds the flow area so as to enable fluid flow. Gravel introduction flow pipe.