JP5703157B2 - Sewer flow switching member and switching method, and manhole reconstruction method. - Google Patents

Description

  The present invention relates to a sewage flow switching member and switching method, and a manhole reconstruction method.

The precast manhole on the sewage trunk line that was mass-produced in the latter half of the Showa era has a phenomenon in which the shear keys of the upper and lower pieces are destroyed due to the synergistic action of liquefaction and earthquake motion due to the earthquake, and the dam is dropped and damaged.
In addition, depending on the location, the phenomenon of corrosion and deterioration of the lower surface of the inner floor of the manhole and the inner wall surface is also progressing. This is due to the influence of hydrogen sulfide gas produced by sulfate-reducing bacteria.
To do so, the manhole installed on the sewage trunk line must be rebuilt, but this is extremely difficult for the following reasons.
<1> A large amount of water flows down the sewage trunk line, and the facilities are large in order to be pumped up and diverted.
<2> In the detour method using a pump, in the unlikely event that the pump stops functioning, sewage overflows into the surrounding area, creating a major social problem.
<3> The sewer main line is generally installed at a large depth, and since the groundwater level is high, there is a risk of boiling.
Despite the difficulties described above, if the sewerage system becomes unavailable, a wide range of residents will be unable to use the water and sewage systems, and social ripples and economic losses will not be measured.
For this purpose, for example, a sewer flow switching method as shown in Non-Patent Document 1 has been developed and adopted.
In this method, the upper half of the sewer pipe is removed in the manhole, a cylinder with a lid called a “super plug” is inserted into the upper and lower sides of the sewer pipe, and the two cylinders are connected by a small diameter pipe. This is a method of renovation while ensuring the flow of sewage.

Super plug system construction method. (Www.acon.co.jp/spsm/index.html)

  The conventional sewage flow switching method described above does not bypass the sewage by pumping it, so it is possible to maintain the sewage flow, but there is a large amount of work performed by workers entering the sewage. In addition, there is a problem that the burden of maintenance and management of air pressure is large for securing the water-stopping property of the plug, and the equipment cost is high.

  The sewage flow switching member of the present invention that solves the above-described problems is an insertion tube that is a cylindrical body having an outer diameter close to the inner diameter of the sewage pipe to be switched, and a small diameter that is a cylindrical body having an inner diameter smaller than that of the insertion pipe. A sewage flow switching member comprising a tube, a trumpet tube that is a conical cylinder connecting the insertion tube and the small-diameter tube, and an opening that is formed by cutting a portion of the trumpet tube. Is.

  Further, in the method for switching the sewage flow of the present invention, the above-mentioned switching member is suspended in the manhole, and the insertion pipe of one switching member is inserted into the upstream sewage pipe with the opening side down, Insert the switching member insertion pipe into the downstream sewage pipe with the opening facing down, connect the opposing small-diameter pipes with a connecting pipe, and then connect both switching members and the connecting pipe to the insertion pipe. Rotate in the direction with the central axis of the rotation axis as the rotation axis, position the opening on the upper side, and open the downstream insertion pipe through the small diameter pipe with the sewage flow taken from the open end of the upstream insertion pipe It features a method of switching the sewage flow that flows out from the end.

  In the manhole reconstruction method of the present invention, the manhole is dismantled by inserting the steel pipe around the existing manhole after the sewage flow is switched to the state of flowing down the switching member by the above switching method. And the sewer installation part are exposed, the rolled concrete is placed around it, a new precast manhole is assembled, the fluidized soil is filled around it, the steel pipe is pulled up, and then the fluidized soil is It is characterized by a manhole restructuring method that replaces concrete.

Since the sewage flow switching method and the sewage flow switching member of the present invention are as described above, the following effects can be obtained.
<1> Switching between the natural flow of the sewage flow and the flow in the small-diameter pipe can be performed by only rotating the switching member with the flow direction as the rotation axis, so that the switching operation is very simple.
<2> The rotation of the switching member, that is, the switching of the sewage flow can be performed without stopping the sewage flow for a moment, so that it is extremely efficient and stable.
<3> Since the switching member is a simple member obtained by simply connecting a plurality of cylinders, it is lightweight, easy to handle, and inexpensive.
<4> Since the manhole can be reconstructed after the sewage flow is completely switched, damaged parts such as the manhole and sewer installation points can be reliably repaired.
<5> Reinforced manholes can be reconstructed by dismantling existing manholes, then installing new manholes and placing concrete around them.

The perspective view of the Example of the switching member of the sewer flow of this invention. Explanatory drawing of the state before switching of a sewer flow. The perspective view of the state which rotated the switching member. Explanatory drawing of the state which switched the sewage flow. Explanatory drawing of the Example for ensuring water stop. The perspective view of the other Example of the switching member. Explanatory drawing of the construction order of manhole reconstruction after switching. Explanatory drawing of the construction order of manhole reconstruction after switching. Explanatory drawing of the construction order of manhole reconstruction after switching. Explanatory drawing of the construction order of manhole reconstruction after switching. Explanatory drawing of the construction order of manhole reconstruction after switching. Explanatory drawing of the construction order of manhole reconstruction after switching. Explanatory drawing of the construction order of manhole reconstruction after switching.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

<1> Overall configuration. (Figs. 1 and 3)
The sewage flow switching member 1 of the present invention includes an insertion pipe 11, a small diameter pipe 12, and a trumpet pipe 13.

<2> Insertion tube.
The insertion tube 11 is a simple cylinder with both ends open.
The outer diameter of the insertion pipe 11 is configured to be as close as possible to the inner diameter of the sewer pipe to be switched.

<3> A small diameter tube.
The small diameter tube 12 is a cylindrical body having an inner diameter smaller than that of the insertion tube 11.
This small-diameter tube 12 is also a simple cylinder having both ends opened.
The cross-sectional area of the small-diameter pipe 12 is required to be equal to or larger than the cross-sectional area where the sewage to be switched can flow at almost the same speed as the sewage in the sewage pipe. Then, sewage overflows from the opening part mentioned later and cannot switch.

<4> Trumpet tube.
The trumpet tube 13 is a cylindrical body having a truncated cone shape with both ends opened.
Since it has a truncated cone shape, one opening serves as an enlargement port, and the other opening serves as a reduction port having a smaller area.
The inner diameter of the enlarged opening of the trumpet tube 13 is set to the same size as the inner diameter of the insertion tube 11.
On the other hand, the inner diameter of the reduction port of the trumpet tube 13 is configured to be the same as the inner diameter of the small-diameter tube 12.
The insertion tube 11 is attached to the expansion port of the trumpet tube 13 and the small-diameter tube 12 is connected to the reduction port.
In the illustrated embodiment, the shape in which the central axes of the insertion tube 11 and the small-diameter tube 12 are made to coincide is shown, but a configuration in which the central axes of both are shifted can also be adopted. (Fig. 6)

<5> Opening.
A portion of the trumpet tube 13 is cut to open the opening 14.
In that case, the trumpet tube 13 has a shape in which a part of the truncated cone is cut out.
As will be described later, the opening 14 serves as an inlet and outlet for a sewage flow at the time of switching.
Therefore, the area of the opening 14 needs to be an area that can completely take in the sewage from the sewage pipe.

<6> Switching method.
Next, the method for switching the sewage flow of the present invention will be described.
Various constructions such as manhole reinforcement, which are separately performed before the switching of the sewage flow, are also envisaged, but these are various and different from the present invention, so the description thereof is omitted.
The amount of sewage is assumed not to flow down the entire cross section of the sewage pipe but to the case where it flows down the lower half of the sewage pipe.

<7> Hanging the member down.
A single manhole a is connected to an upstream and downstream sewage pipes b so that the sewage flows through the b manhole a.
Two switching members 1 described above are suspended in the manhole a.

<8> Insertion of the insertion tube. (Figure 2)
The insertion pipe 11 of one switching member 1 is inserted into the upstream sewage pipe b1.
In that case, the small-diameter pipe 12 is inserted toward the manhole a side and the opening 14 of the trumpet pipe 13 is positioned on the lower side.
The insertion pipe 11 of the other switching member 1 is inserted into the downstream sewage pipe b2.
Also in this case, similarly to the switching member 1, the small diameter tube 12 is inserted toward the manhole a and the opening 14 of the trumpet tube 13 is positioned below.
Each insertion pipe 11 is inserted into the sewage pipes b1 and b2 by a certain distance, and is installed in a state where the ends of the small diameter pipes 12 of the switching members 1 on both sides are exposed in the manhole a by a certain distance.

<9> Flow of sewage before switching.
In this state, the openings 14 of the trumpet pipes 13 on both sides are located toward the lower side of the sewage pipe, that is, the bottom side. (Figures 1 and 2)
Therefore, sewage flows from the open surface of the insertion tube 11 of the upstream switching member 1 and flows into the manhole a from the opening 14 of the trumpet tube 13.
The sewage that has passed through the manhole a flows into the insertion tube 11 from the opening 14 of the trumpet tube 13 on the downstream side, and flows out of the downstream sewage tube from the downstream open surface of the insertion tube 11.
Therefore, no sewage flows into the small diameter pipe 12.

<10> Connection.
The small-diameter pipes 12 facing each other in the manhole a are connected by the connecting pipe 2.
The connecting pipe 2 is a flexible pipe so that the connection within the narrow manhole a is easy.
Since sewage does not flow into the small diameter pipe 12, the operation is simple.
In this way, it is possible to connect between the small-diameter pipes 12 facing each other.

<11> Rotation of the switching member. (Figs. 3 and 4)
Thereafter, both switching members 1 are rotated in the sewer pipe about the central axis of the cylindrical insertion pipe 11 as an axis.
The rotation simultaneously rotates the switching member 1 on both sides and the entire connection pipe 2.
By this rotation, the openings 14 of the trumpet tubes 13 on both sides move from the downward position to the upward position.

<12> Flow of sewage after switching. (Fig. 4)
When the openings 14 on both sides are in the above positions, the sewage from the upstream is not taken in through the opening 14 but is taken in from the upstream open surface of the insertion tube 11.
The sewage introduced into the switching member 1 from the upstream side of the insertion pipe 11 is discharged to the sewer pipe from the open surface of the insertion pipe 11 of the downstream switching member 1 through the connection pipe 2.
In other words, in this state, the opening 14 positioned in the upward direction no longer has any effect.

<13> Flow during switching.
Even before and after the switching, all the sewage is taken from the open surface of the insertion tube 11 on the upstream side.
The sewage thus introduced flows out from the opening 14 toward the manhole a before switching, and flows out to the switching member 1 on the downstream side through the connecting pipe 2 after switching.
Therefore, during switching, that is, during rotation of the switching member 1, the amount of sewage taken from the open surface of the insertion pipe 11 gradually decreases from the opening 14, and the amount of inflow into the connection pipe 2 accordingly. Presents a phenomenon that gradually increases.
The ratio of the amount of inflow to the connecting pipe 2 gradually increases, and finally the amount of outflow from the opening 14 becomes zero, and all is supplied to the connecting pipe 2.
This completes the switching of the sewage flow.

<14> Ensuring waterstop.
In order to prevent the upstream switching member 1 from being pushed out by the sewage water pressure or to completely block the leakage of water into the manhole a, as shown in FIG. To do.
The closing material 3 can be constituted by, for example, a bag filled with mortar, a sandbag, an air bag, or the like.
If the gap 3 between the small-diameter pipe 12 and the sewage pipe located on both sides is filled in the center of the manhole a and the reaction force frame 31 is installed between the small diameter pipe 12 and the sewer pipe, a complete water-stopping effect can be achieved. .

<15> Subsequent work.
If the entire amount of sewage that has flowed down the manhole a flows down the connecting pipe 2, there is no sewage in the manhole a, and free work is possible.
Therefore, reinforcement of the joint part of the manhole a and the sewer pipe, and other construction can be performed.
Next, the embodiment will be described with reference to FIG. 7 and subsequent drawings . Of course, other known sewage flow switching methods such as the method of the prior art document and the method of stopping water with an air bag can be adopted.

<16> Ground improvement. (Fig. 7)
The ground is improved around the damaged existing manhole a1 and the existing sewer pipe b connected thereto.
For the ground improvement, for example, a well-known technique such as injecting cement material into the ground and stirring can be employed.

<17> Removal of existing manholes. (Fig. 8)
In a state of surrounding the outer periphery of the existing manhole a1, a steel pipe 4 having an inner diameter larger than the outer diameter is press-fitted.
The inside of the steel pipe 4 is filled with muddy water, the dismantling machine is suspended from the ground, excavation of the earth and sand in the steel pipe 4 and the dismantling of the existing manhole a1 are performed.
In this way, it is possible to prevent disturbance of the surrounding ground due to boiling at the tip of the steel pipe during excavation by filling the muddy water.

<18> Damping of steel pipes. (Fig. 9)
When the steel pipe 4 that has been pressed into the ground eventually penetrates into the improved ground, water leakage is injected into the repair area by injecting a water-stopping agent from the ground to the outer circumference of the steel pipe 4 and the area above the improved ground. To prevent.
This is because, as described above, the sewer main line is in a deep position, so that the possibility of boiling is high.
The tip of the steel pipe 4 stops penetration at a position near the upper part of the sewer pipe b without punching out the sewer pipe b.

<19> Winding concrete.
The muddy water inside the steel pipe 4 is pumped out.
As described above, since all of the sewage flowing through the sewer pipe b flows inside the switching member 1, work can be freely performed inside the manhole a1 when the muddy water is removed.
Therefore, the periphery of the sewage pipe b is dug down from the periphery of the sewage pipe b to the lower part by hand digging while earthing the sewage pipe b from the tip of the steel pipe 4 with the sheet pile 5. (Fig. 10)
The attachment location of the existing manhole a1 and the sewer pipe b is exposed in the state.
And a damage state is confirmed and when the attachment part etc. are damaged, the attachment part winding concrete 6 is cast in the state which winds up the sewer pipe b. (Fig. 11)

<20> Established a precast manhole. (Fig. 12)
Precast members for the new manhole a2 are sequentially suspended and stacked to construct the new manhole a2.
For example, fluidized soil 7 is introduced between the new manhole a2 and the steel pipe 4 in parallel with the rise of the new manhole a1.
If the steel pipe 4 is pulled out in this state, the wall surface around the tip of the steel pipe being pulled out does not collapse, and the steel pipe 4 can be recovered in a safe state.
The fluidized soil contains an appropriate amount of solidifying material such as cement, so that damage due to fluidization can be suppressed against future earthquakes.

<21> new site strokes set manhole.
Reinforcing bars are arranged on the inner surface of the steel pipe 4 in advance, the inner mold 8 is installed, and concrete is put in while the steel pipe 4 is pulled out .
If the steel pipe 4 is pulled out in this state, the wall around the tip of the steel pipe 4 that is being pulled out does not collapse, and the steel pipe 4 can be recovered in a safe state, and a manhole a2 for on-site placement is newly established. Can do.
Thus, the repair of the damaged part of the existing manhole a1 or the damaged part of the attachment part between the existing manhole a1 and the sewer pipe b is completed, and the construction of the new manhole a2 is also completed.
Thereafter, the switching member 1 is removed, and the sewage from the upstream sewage system b flows through the manhole a to the downstream sewage system b and returns to the original state.

1: Switching member 11: Insertion pipe 12: Small diameter pipe 13: Trumpet pipe 14: Opening part 2: Connection pipe 3: Blocking material 4: Steel pipe 5: Sheet pile 6: Winding concrete 7: Fluidized soil 8: Reinforced concrete a1 : Existing manhole a2: New manhole b: Sewage pipe

Claims (3)

An insertion pipe that is a cylindrical body having an outer diameter close to the inner diameter of the sewer pipe to be switched;
A small-diameter tube that is a cylindrical body having an inner diameter smaller than that of the insertion tube;
A trumpet tube which is a conical cylindrical body connecting the insertion tube and the small diameter tube;
A part of the trumpet tube was cut and opened with an opening.
Sewer flow switching member. Using the switching member according to claim 1,
Hanging this in the manhole,
Insert one switching member insertion pipe into the upstream sewage pipe with the opening side down,
Insert the insertion pipe of the other switching member into the sewage pipe on the downstream side with the opening side down,
Connect the opposing small-diameter pipes with connecting pipes,
After that, both the switching member and the connecting pipe are rotated in the direction having the central axis of the insertion pipe as the rotation axis, and the opening is positioned on the upper side.
The sewage flow taken from the open end of the upstream insertion pipe flows out from the open end of the downstream insertion pipe via the small diameter pipe.
How to switch sewage flow. By the switching method according to claim 2 ,
Switch to a state where the flow of sewage flows down the switching member,
After that, a steel pipe was inserted while filling muddy water around the existing manhole,
Insert and fix the tip of the steel pipe to the improved body that encloses the sewer installation part installed in advance,
Dismantling the manhole,
After exposing the manhole and sewer attachment, place rolled concrete around it,
Assemble a new precast manhole,
The steel pipe is pulled up while filling the fluidized soil or concrete around it,
How to reconstruct manholes.

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