JP2005226406A - Water permeation method for manhole, water permeation structure for manhole - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water permeation method for a manhole and water permeation structure for a manhole capable of avoiding such as an accident of water overflowing from the manhole even in a heavy rainfall. <P>SOLUTION: An outflow opening of an upstream pipe line and an inflow opening of a downstream pipe line facing the outflow opening are provided at the wall face of a manhole formed of a pit and the outflow opening of the upstream pipe line is connected to the inflow opening of the downstream pipe line through a groove-formed invert to construct a manhole water permeation structure. Joint pipes are arranged respectively in the outflow opening of the upstream pipe line and the inflow opening of the downstream pipe line. Mutual joint pipes are connected by connection pipe having the same sectional area with a pipe constituting the upstream pipe line and the downstream pipe line. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to a manhole water flow method and a manhole water flow structure provided in a sewer, and in particular, improves the water flow performance, and can reduce the occurrence of an accident in which a manhole overflows even during heavy rain. A method and a manhole water flow structure are proposed.

FIG. 9 shows the internal structure of a general manhole. In the figure, 10 is the ground surface, 20 is a manhole built underground, 30 is an upstream pipeline, 40 is a downstream pipeline, and 50 is an invert.
As is generally well known, the manhole 20 is composed of a pit that is dug down from the ground surface 10 into the ground, and an outlet 31 of the upstream pipe 30 is provided on the wall of the pit and is opposed to the outlet 31. Thus, the inlet 41 of the downstream pipe 40 is provided. The bottom surface of the manhole 20 is made of concrete and has a floor surface. The floor surface is an inclined surface that gradually decreases from the outlet 31 toward the inlet 41, and an invert 50 composed of a semi-tubular groove is formed on the inclined surface.
Normally, the sewage flows through the invert 50, but the invert 50 may overflow at the peak flow rate.

  By the way, when heavy rain falls in a short time, such as heavy rain, rainwater concentrates on the sewer pipe from the side ditch etc. of the road, so the upstream pipeline 30 and the downstream pipeline 40 are in a full state. It will be the situation to pour water. Under this condition, in the manhole 20, there is a loss due to rapid expansion on the outflow side and a loss due to rapid contraction on the inflow side. Due to the presence of this loss, when heavy rain reaches a long time, water gradually accumulates in the manhole 20, and if it worsens, an accident occurs in which the lid of the manhole 20 is blown up and the surface 10 overflows.

Here, the loss due to sudden expansion and the loss due to rapid contraction occurring inside the manhole 20 will be briefly described. FIG. 12 shows models of the rapid expansion portion and the rapid contraction portion. FIG. 12A shows a rapid expansion section, and FIG. 12B shows a rapid contraction section.
In the rapid expansion portion, water flowing at the flow velocity V1 through the pipe line having the tube diameter D1 is discharged to the tube diameter D2, and the flow velocity is changed to V2.
In the abrupt contraction portion, the state in which the flow rate of the pipe diameter D1 is changed from the state of flowing at the flow velocity V1 to the pipe passage of the pipe diameter D2 and the flow velocity is changed to V2 is shown.

Using the parameters shown in this model, the general formula for calculating the loss head due to rapid expansion and the loss head due to rapid contraction is:
(Loss head due to rapid expansion hse)
hse = (V1−V2) ² / 2g = (1−A1 / A2) ² · V1 ² / 2g
= {1- (D1 / D2) ² } · V1 ² / 2g
= Fse · V1 ² / 2g (1)
Where hse: head of loss due to rapid expansion (m) (general value: 0.5)
fse: {1- (A1 / A2)} ² : Rapid expansion loss coefficient V1, V2: Pipe flow velocity before and after rapid expansion and contraction (m / s)
A1, A2: Pipe cross-sectional area before and after rapid expansion and contraction (m ² )
D1, D2: Pipe diameter before and after rapid expansion and contraction (m)
(Loss head hsc due to rapid contraction)
hsc = (1 / Cc−1) ² · V2 ² / 2g = fsc · V2 ² / 2g (2)
Where hsc: head loss due to rapid contraction (m) (general value: 1.0)
Cc: contraction coefficient fsc: {(1 / Cc) -1} ² : rapid contraction loss coefficient V2: pipe flow velocity after rapid contraction (m / s)
(Head loss due to rapid expansion / contraction h)
h = hsc + hgc = fsc (V1 ² / 2g) + fsc (V2 ² / 2g) (3)
Where hsc: head of loss due to rapid expansion (m)
hge: Loss head due to gradual expansion (m)
fsc: {1- (A1 / A2)} ² : Rapid contraction loss coefficient V2: Pipe flow velocity after rapid contraction (m / s)
FIG. 13 shows a trial calculation result of the loss head with respect to the flow rate of the sewer pipe according to these general formulas. Generally, the diameter of the pipeline is set so that the flow velocity is designed in the range of 0.6 to 3.0 (m / s), but the loss head is 0.028 m to 0.689 m. A rise in the water level in the manhole is inevitable. In particular, the water level rises more markedly toward the upstream of the sewer.

In the present invention, the outlet of the upstream pipeline and the inlet of the downstream pipeline are provided on the wall surface of the manhole constituted by the pits, and the outlet of the upstream pipeline and the downstream are opposed to the outlet. In the manhole water passing method in which the sewage is passed through a groove-shaped invert between the inlet and the inlet of the side pipe, a section approximately equal to the cross-sectional area of the upstream pipe and the downstream pipe in the manhole. We propose a manhole flow method that allows sewage to flow through an area pipe.
In the present invention, further, an outlet of the upstream pipe line and an inlet of the downstream pipe line are provided on the wall surface of the manhole composed of the pits so as to face the outlet, and the outlets of these upstream pipe lines are provided. In the manhole water flow structure configured by connecting the inlet of the downstream pipe and the inlet of the downstream pipe with a grooved invert, a joint pipe is provided at each of the outlet of the upstream pipe and the inlet of the downstream pipe. A manhole water flow structure is proposed in which the joint pipes are connected and connected to each other with a connecting pipe having a cross-sectional area equivalent to that of the pipes constituting the upstream side pipe and the downstream side pipe.

According to the present invention, in the manhole water passage structure according to claim 2, the joint pipe has a flange at a substantially central portion in the pipe axis direction, and one of the pipes divided by the flange is connected to the upstream pipe and the downstream pipe. A manhole water passage structure is proposed in which the pipes are inserted into both sides of the road, and the other pipes are protruded into the manholes, and the connecting pipes are connected to each other of the protruding joint pipes.
The present invention further proposes a manhole water passage structure according to any one of claims 2 and 3, wherein the connection pipe is constituted by a divided pipe which can be divided in a circumferential direction.

The present invention further proposes a manhole water passage structure according to any one of claims 2 and 3, wherein the connection pipe has an opening lid on the upper surface side.
The present invention further proposes a manhole water passage structure according to any one of claims 2 to 5, wherein a rainwater suction hole is provided on the upper surface side of the connection pipe.

According to the manhole water passing method and the manhole water passing structure proposed in claim 1 and claim 2 of the present invention, the upstream side pipe and the downstream side pipe are connected to the upstream side and the downstream side even in the manhole. Since connection pipes having a cross-sectional area substantially equal to the cross-sectional area of the pipe line are connected, it is possible to avoid loss due to sudden expansion and loss due to sudden contraction at both the outlet and the inlet. As a result, the phenomenon that the water level rises for each manhole can be prevented.
According to the manhole water passage structure proposed in claim 3 of the present invention, the connecting pipe provided in the manhole is connected to the outlet and the inlet by the joint pipe provided with the flange. The connection state can be maintained, and it can endure safely even when the water volume increases.

Furthermore, according to the manhole water passage structure proposed in claim 4 of the present invention, since the connecting pipe can be divided in the circumferential direction, the inside of the connecting pipe can be easily inspected.
Furthermore, according to the manhole water passage structure proposed in claim 5 of the present invention, since the connection pipe is provided with a lid, the inside of the connection pipe can be inspected by opening the lid. Therefore, it is possible to obtain a manhole water passage structure that can perform security and inspection more easily.
According to the manhole water passage structure proposed in claim 6 of the present invention, since the rainwater suction hole is provided on the upper surface of the connecting pipe, rainwater enters the manhole from the manhole cover and the rainwater enters the manhole. However, if the amount of sewage flowing through the connection pipe returns to a steady state, that is, about half the pipe diameter, the rainwater collected in the manhole through this rainwater suction hole will enter the connection pipe. It is sucked and sucked into the downstream pipe line. Therefore, rainwater does not accumulate in the manhole forever.

  In the present invention, the connection pipe having a cross-sectional area substantially equal to the cross-sectional area of the upstream and downstream pipes is connected between the outlet of the upstream pipe provided on the wall surface of the manhole and the inlet of the downstream pipe. And since the water flow method which does not change the cross-sectional area of a flow path inside the manhole was proposed, it can prevent that both the loss by the rapid expansion and the loss by rapid contraction which generate | occur | produce for every manhole are generated. Further, since the manhole water-passing structure is provided with a rainwater suction hole on the upper surface of the connecting pipe, even if rainwater enters the manhole directly from the ground surface, the rainwater is sucked into the connecting pipe and does not accumulate in the manhole.

An embodiment of a manhole water passing method and a manhole water passing structure according to the present invention will be described with reference to FIGS. Portions corresponding to those in FIGS. 9 to 11 are denoted by the same reference numerals. In the present invention, the cross-sectional area of the upstream pipeline 30 and the downstream pipeline 40 is between the outlet 31 of the upstream pipeline 30 opened in the wall surface of the manhole 20 and the inlet 41 of the downstream pipeline 40. And a water flow method in which a connecting pipe 60 having a cross-sectional area substantially equal to the cross-sectional area is connected, and the inside of the manhole 20 is also passed through a pipe having a cross-sectional area substantially equal to the cross-sectional areas of the upstream pipe 30 and the downstream pipe 40. It is a structure.
For this purpose, joint pipes 70 are provided at both the outlet 31 and the inlet 41, and the outlet 31 and the inlet 41 are connected via the joint pipe 70 via the connection pipe 60. As shown in FIG. 3, the joint pipe 70 includes a flange 71 at the substantially center in the pipe axis direction, and one pipe 72 divided into two by the flange 71 is inserted into the outlet 31 and the inlet 41. In the example shown in FIG. 3, the pipe 72 is inserted into the inlet 41. The other pipe 73 divided by the flange 71 is projected from the inner wall surface of the manhole 20, and the projecting pipes 73 are connected to each other by the connecting pipe 60. The joint pipe 70 and the connecting pipe 60 are pipes having a cross-sectional area substantially equal to the cross-sectional areas of the pipes used for the upstream side pipe line 30 and the downstream side pipe line 40, respectively. In addition, 80 shown in FIG. 1 shows the anchor for fixing the connecting pipe 60 to a floor surface.

As shown in FIG. 4, the connecting pipe 60 is divided into two in the circumferential direction, and the joint pipe 70 is sandwiched between the two divided pipes, and the pipes 73 of the joint pipe 70 are passed between each other. In the example shown in FIG. 4, a case where the divided connection pipe 60 is bundled with a wire 81 is shown. It is to be noted that a filling body such as a resin system or mortar is filled between the connection pipe 60 and the invert 50, and the gap can be closed so that no gap is formed between the connection pipe 60 and the invert 50.
Further, in the present invention, a rainwater suction hole 61 is formed on the upper surface side of the connection pipe 60. The rain water suction holes 61 may be formed uniformly distributed in the longitudinal direction of the connecting pipe 60 as shown in FIG. By providing the rainwater suction hole 61, even if rainwater enters directly from the lid portion of the manhole 20 and the rainwater is accumulated in the manhole 20, the water level of the rainwater in the manhole 20 is connected to the connecting pipe 60. When reaching the position of the rainwater suction hole 61 formed in the rainwater, the rainwater is sucked into the connection pipe 60 from the rainwater suction hole 61. Therefore, the rainwater level that has directly entered the manhole 20 does not rise significantly from the position of the rainwater suction hole 61, and a large amount of rainwater can be prevented from accumulating in the manhole 20.

The rainwater collected up to the position of the rainwater suction hole 61 oozes out from the gap between the floor surface of the manhole 20 and the peripheral wall, or passes through the gap between the connecting pipe 60 and the joint pipe 70 into the sewer pipe. It is sucked and nature is canceled.
Rainwater that directly enters the manhole 20 is considered to enter through the vent holes formed in the manhole cover. That is, in the case of a standard lid with a diameter of 600 mm, 22 gas vent holes are formed, and the diameter of each gas vent hole is about 14 mm. In the case of a standard lid with a diameter of 750 mm, 22 gas vent holes with a diameter of 14 mm are formed. Therefore, the rain water suction holes 61 formed in the connection pipe 60 may be prepared with holes having the same number and diameter as the gas vent holes.

FIG. 6 shows a second embodiment of the connecting pipe 60. In the second embodiment, the structure for passing the connecting pipe 60 to the upstream side and the downstream side using the joint pipe 70 is the same as that of the first embodiment, but the fastening structure of the connecting pipe 60 is characteristic. That is, a case is shown in which the connecting pipe 60 is divided into two in the vertical direction, the reinforcing rib 62 and the flange 63 are formed on the outer periphery of the divided dividing surface, and the flange 63 is fastened with the bolt 64. Also in this case, a rainwater suction hole 61 is formed on the upper side, and the rainwater directly entering the manhole 20 is sucked through the rainwater suction hole 61.
According to the structure of the second embodiment, the upper half of the connecting pipe 60 can be removed by loosening the bolt 64 and removing the bolt 64. As a result, there is an advantage that the inside of the connecting pipe 60 can be easily inspected.

FIG. 7 shows a third embodiment of the connection pipe 60. Even in the third embodiment, the structure in which the connecting pipe 60 is passed to the upstream side and the downstream side using the joint pipe 70 is the same as that in the first embodiment, but the case where the connecting pipe 60 is divided into three in the circumferential direction is shown. . That is, the upper half constituting the connecting pipe 60 is further divided into two parts, the half parts divided into two are rotatably connected to the lower half part by the hinge 65, and the flange 66 formed on the upper end part is connected to each other by the bolt 64. The case where it is set as the structure to fasten is shown.
According to the structure of the third embodiment, by loosening and removing the bolt 64, the upper half portion of the connection pipe 60 can be rotated by the hinge 65 to open the pipe. As a result, there is an advantage that the inside of the connection pipe 60 can be inspected more easily than the structure of the second embodiment.

  FIG. 8 shows a fourth embodiment of the connection pipe 60. In FIG. 8, A is a sectional view and B is a plan view. In the fourth embodiment, a case where an opening lid 67 is provided on the upper portion of the connection pipe 60 is shown. The opening lid 67 is normally fastened to the connection pipe 60 with, for example, a wire rope 81. When inspection is necessary, the fastening of the wire rope 81 is released and the opening lid 67 is removed from the upper part of the connection pipe 60. An opening can be formed in the portion from which the opening lid 67 is removed, and an operator can enter the inside of the connecting pipe 60 through this opening or check the inside of the connecting pipe 60 from the outside of the connecting pipe 60. Can do. Reference numeral 68 denotes a handle used when the opening lid 67 is removed.

  The manhole water passing method and the manhole water passing structure according to the present invention are suitable for application to a public corporation or a sewerage facility operated by a company.

Sectional drawing for demonstrating Example 1 of this invention. The top view which looked at FIG. 1 from the upper part. Sectional drawing for demonstrating the connection structure of the connecting pipe used as the principal part of this invention. Sectional drawing for demonstrating Example 1 of the connecting pipe used as the principal part of this invention. The top view for demonstrating the example of arrangement | positioning of the rain water suction hole shown in FIG. Sectional drawing for demonstrating Example 2 of this invention. Sectional drawing for demonstrating Example 3 of this invention. Sectional drawing for demonstrating Example 4 of this invention. Sectional drawing for demonstrating the prior art. FIG. 10 is a cross-sectional view seen from a direction different from 90 ° of the cross-sectional view shown in FIG. 9. The top view which looked at FIG. 9 from the upper part. The figure for demonstrating the loss by the rapid expansion which has generate | occur | produced in the conventional manhole, and the loss by rapid contraction. The figure which shows the trial calculation value of the loss head with respect to the flow velocity of the sewer pipe explained using FIG.

Explanation of symbols

10 Ground 62 Reinforcement ribs
20 Manhole 63, 66 Flange 30 Upstream pipe 64 Bolt 31 Outlet 65 Hinge 40 Downstream pipe 67 Opening lid 41 Inlet 68 Handle 50 Invert 70 Joint pipe 60 Connection pipe 71 Flange 61 Rain water suction hole 72 One pipe
73 The other pipe

Claims (6)

An outlet of the upstream pipeline and an inlet of the downstream pipeline are provided on the wall surface of the manhole constituted by the pits, and the outlet of the upstream pipeline and the downstream pipeline are opposed to the outlet. In the manhole water flow method of connecting sewage with a grooved invert between the inlet and
A manhole water passing method, wherein sewage is passed through a pipe having a cross-sectional area substantially equal to a cross-sectional area of the upstream pipe and the downstream pipe inside the manhole. An outlet of the upstream pipeline and an inlet of the downstream pipeline are provided on the wall surface of the manhole constituted by the pits, and the outlet of the upstream pipeline and the downstream pipeline are opposed to the outlet. In the manhole water flow structure that is configured by connecting the inflow port with a groove-shaped invert,
A joint pipe is provided at each of the outlet of the upstream pipe and the inlet of the downstream pipe, and the joint pipes have a cross-sectional area equivalent to that of the pipe constituting the upstream pipe and the downstream pipe. Manhole water flow structure characterized by a structure connected by a connecting pipe with   3. The manhole water passage structure according to claim 2, wherein each of the joint pipes has a flange at a substantially center in the pipe axis direction, and each of the pipes divided by the flange is connected to the upstream pipe line and the downstream pipe line. A manhole water-passing structure characterized by being inserted into both of the pipes, projecting the other pipe into the manhole, and connecting the connecting pipe to the projected joint pipe.   4. The manhole water passage structure according to claim 2, wherein the connection pipe is constituted by a divided pipe that can be divided in a circumferential direction. 5.   4. The manhole water passage structure according to claim 2, wherein the connection pipe has an opening lid on the upper surface side. 5.   6. The manhole passage structure according to claim 2, further comprising a rainwater suction hole on an upper surface side of the connection pipe.

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