JP4339233B2 - Sewer Fushietsu structure - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a structure of an overpass part of a sewer, and particularly to an overpass part structure suitable for adding a function for preventing sand accumulation to existing facilities.

  Generally, when it is necessary to lay an underground waterway across an obstacle such as a river, a railway, or an underground burial that is difficult to relocate, the sewerage is installed in the section where the obstacle exists (reverse siphon type communication passage). ) (See, for example, Patent Documents 1 and 2). Among the examples of the structure of the Fushigoe adopted in the field of combined sewerage systems, those that incorporate an air cushion siphon system are known (for example, see Non-Patent Documents 1 and 2). Explained. FIG. 4 shows a structural example of a type in which an air cushion chamber is formed by two gates.

  In this structure, as shown in FIG. 4A, an upstream sewage channel 101 and a downstream sewage channel 102 are provided on the upstream side and the downstream side with the obstacle 103 interposed therebetween, and communicated with each of the sewage channels 101, 102. Thus, an upstream side cover room 111 and a downstream side cover room 112 are vertically provided on both sides of the obstacle 103. And the lower end of both the overpass chambers 111 and 112 provided vertically is connected by the overpass tube 113 that passes under the obstacle 103.

  In addition, gates 117 and 118 for closing the communication ports 115 and 116 from the upper side are provided at the communication ports 115 and 116 at both ends of the respective chambers 111 and 112 and the crossover tube 113 so as to be movable up and down. The gates 117 and 118 can be opened and closed by a drive mechanism (not shown). When the two gates 117 and 118 are closed to some extent as shown in FIG. 4B, a space P for storing air (hereinafter referred to as an air cushion chamber) P can be formed in the upper portion of the overpass pipe 113. By introducing air from the outside and containing it, the cross section of the flow path through which the sewage in the overpass pipe 113 flows can be reduced and the flow can be accelerated.

  When operating this gate type air cushion and siphon system, as shown in FIG. 4A, the gates 117 and 118 are normally fully opened, and the flow passage cross section of the overpass pipe 113 is used widely as shown in FIG. Shed. When a large cross section of the flow path is used, the flow becomes loose, and there is a possibility that the deposit T will accumulate in the overpass 113. Therefore, the deposit removal operation as shown in FIG. 4B is performed at an appropriate timing. During the deposit removal operation, the gates 117 and 118 are closed to some extent. Then, air is introduced from the outside into the air cushion chamber P formed in the upper part of the inside of the overpass tube 113, and by holding this, the cross section through which the sewage flows in the overpass tube 113 is reduced, so that the sewage The flow is accelerated and the deposit T is washed away. By operating in this way, it is possible to reduce the burden of cleaning in the overpass 113.

  In addition, it is possible to prevent deposits from being accumulated in the overpass pipe 113 in advance by switching between rainy weather and sunny weather when there is a difference in the amount of sewage. That is, when the amount of sewage is fine, when the flow passage cross section of the pass-through cross pipe 113 is fully opened, the flow rate becomes slow and deposits are likely to accumulate. Therefore, the gates 117 and 118 are closed to an appropriate degree of opening. By confining air in the transverse tube 113, the cross section through which the sewage flows is reduced and the flow is made faster. By doing so, it is possible to make it difficult for deposits to accumulate in the overpass pipe 113. In addition, when the amount of sewage increases during rainy weather, the air sealed during fine weather is removed and the gates 117 and 118 are fully opened so that a large amount of sewage can flow.

  As another known example, as shown in FIG. 5, air bags 127 and 128 are respectively provided at both end connection ports 115 and 116 of the overpass tube 113 instead of the above-mentioned gates 117 and 118 (see FIG. 4). If necessary, the air bags 127 and 128 are inflated by introducing air into the air bags 127 and 128 as necessary, so that the both end communication ports 115 and 116 of the overpass tube 113 are cross-sectioned from above. The air cushion chamber P is formed in the upper part of the flow passage cross section of the overpass pipe 113, and air is introduced into the air cushion chamber P through the air blowing pipe 123. In some cases, the substantial flow path cross section of the tube 113 is reduced.

  As another known example, as shown in FIG. 6, instead of the aforementioned gates 117 and 118 (see FIG. 4) and air bags 127 and 128 (see FIG. 5), both ends of the overpass tube 113 are connected. Elbow pipes 137 and 138 with openings facing downward are connected to the mouths 115 and 116, and air is introduced into the overpass pipe 113 as necessary. In some cases, the substantial flow passage cross section of the overpass pipe 113 is reduced by confining air in the upper air cushion chamber P.

JP 2002-348948 A JP 2003-253739 A “Combined Sewerage and Fushikoshi” written by Hiroshi Suzuki, Public Investment Journal, Inc. December 25, 2002 Tokyo Metropolitan Sewerage Bureau Internet <URL: http://www.gesui.metro.tokyo.jp/odekake/syorijyo/03_13.htm>

By the way, in the conventional sewer subsidence structure mentioned above, there existed the following problems.
That is, in any structure of the conventional example, the effective flow cross-sectional area of the overpass tube is reduced by introducing air into the overpass tube 113, so that the compressor ( It is necessary to install an air supply pipe 140 and an air supply pipe 140, and to prevent the air introduced into the pipe from leaking (gates 117 and 118, air bags 127 and 128, elbow pipes 137 and 138, etc.) ) Was necessary. Therefore, since the configuration becomes complicated and the cost burden increases, it has been impossible to easily apply to the existing oversunk structure.

  In view of the above circumstances, an object of the present invention is to provide an overpass structure that can be easily applied to existing facilities at a low cost with a simple configuration.

  The invention according to claim 1 is an upstream side and downstream side chamber connected to an upstream sewer and a downstream sewer arranged with an obstacle therebetween, and extending downward from the obstacle. A subsidence crossing pipe connecting the lower ends of the upstream and downstream subsidence chambers below the obstacles, and a sewer subsidence structure comprising: In this state, an auxiliary pipe extending from the entrance to the outlet of the overpass pipe is provided, and the downstream side of the auxiliary pipe is provided with sufficient flow around the inside of the downstream side overpass chamber. Start up with the passage secured, and communicate with the downstream sewage channel with the upper end as a discharge port, and between the discharge port at the upper end of the auxiliary pipe and the free water surface of the sewage in the downstream passover chamber A weir is provided to raise the free water surface above the discharge port of the auxiliary pipe.

  According to a second aspect of the present invention, in the first aspect, the inlet of the upstream end of the auxiliary pipe is opened to the connecting port between the upstream side depression chamber and the overpass pipe so as to be directed in the direction in which sewage flows. It was made to be characterized.

  The invention of claim 3 is characterized in that, in claim 2, guiding means for guiding sand falling in the upstream side overpassage chamber to the entrance of the auxiliary pipe is provided in the upstream side overpassage chamber. And

  The invention of claim 4 is the invention according to claim 1, wherein the upstream side of the auxiliary pipe is raised in a state where a sufficient flow path is secured around the inside of the upstream side overpassage chamber, and the upper end thereof is used as a suction port. While communicating with the upstream sewage channel, on the other hand, only when sewage flows at a certain level or higher between the suction port at the upper end of the auxiliary pipe and the free water surface of the sewage in the upstream passover chamber, A dam that allows sewage overflow to the free water surface side is provided.

  According to the first aspect of the invention, the flow passage outside the auxiliary pipe disposed in the crossover pipe is connected to the free water surface in the downstream passover chamber. Further, the flow path inside the auxiliary pipe is connected to a discharge port communicating with the downstream sewer. The free water surface of the downstream passover room is maintained at a higher level than the discharge port at the upper end of the auxiliary pipe due to the presence of the weir, so that the sewage is outside the auxiliary pipe connected to the free water surface. In order to flow, water pressure is required to overflow the weir. Since the amount of water is small during fine weather, the water pressure is not generated. Therefore, the sewage does not cross the weir and is kept outside the auxiliary pipe and in the downstream passover chamber.

  On the other hand, the sewage flowing inside the auxiliary pipe does not need to cross the weir, and can flow with a small resistance. For this reason, when the amount of flowing water is small as in fine weather, sewage flows only inside the auxiliary pipe. The flow passage cross-sectional area inside the auxiliary pipe is smaller than that of the crossover pipe, so even when the flow rate of sewage is low, the flow velocity is high, and sand and other solids do not stay and flow downstream with the sewage. And finally transferred to the downstream sewer.

  In addition, when it rains, the amount of sewage increases and the water flow pressure increases beyond the weir, so that sewage flows not only inside the auxiliary pipe but also the entire cross section of the overpass pipe. And the sewage which flowed outside the auxiliary pipe overflows the weir in the downstream side overpass chamber and flows into the downstream side sewage channel. Also in this case, a water level difference of a predetermined level or more is maintained between the free water surface in the downstream passover chamber and the discharge port of the auxiliary pipe because of the presence of the weir. The flow velocity inside is faster than the flow velocity outside the auxiliary pipe. Therefore, even if sand is already accumulated in the auxiliary pipe, it can be expected that the accumulated sand is swept away at a high flow rate. In addition, if the inlet of the auxiliary pipe is open at the connection port between the upstream side and the crossover pipe, the sand that has fallen into the lower part of the upstream side of the overpass room is likely to be sucked into the auxiliary pipe with a high flow velocity in the pipe. Therefore, the auxiliary pipe is transferred at a high flow rate.

  Thus, according to the invention of claim 1, the cross section through which the sewage flows in rainy weather and in fine weather can be automatically switched appropriately according to the small amount of flowing water. Therefore, it is possible to effectively solve the problem that sands accumulate in the subway crossing pipe at the time of fine weather with a small sewage flow rate, and the maintenance interval such as cleaning can be extended. In addition, the configuration is a simple configuration in which an auxiliary pipe is provided from the crossover pipe to the downstream side overpass chamber and a weir is provided in the downstream side overpassage chamber. In particular, since complicated means such as an air source and air leakage prevention are not required at all, it can be easily applied to the existing overpass structure.

  According to the second aspect of the present invention, the inlet of the auxiliary pipe is opened at the connection port between the upstream side depression chamber and the crossover pipe, and the inlet is directed in the direction in which the sewage flows. Sand falling together with sewage in the inside of the cabin can be guided into the auxiliary pipe having a high flow velocity in the pipe, and the retention of sand can be effectively prevented.

  According to the invention of claim 3, since the guiding means for guiding the sand falling in the upstream side overpass chamber to the entrance of the auxiliary pipe is provided, the retention of the sand in the upstream side overpass chamber is further increased. It can be effectively prevented.

  According to the invention of claim 4, the upstream side of the auxiliary pipe is raised in the upstream side overpass chamber, the upper end thereof is communicated with the upstream side sewer as the suction port, and the free water surface in the suction port and the upstream side overpass chamber is provided. Since a weir that allows sewage to overflow to the free water surface only when sewage flows at a certain level or higher, the scum is used as an auxiliary pipe even in fine weather with little water flow. Suction can be efficiently performed, and scum can be prevented from staying in the upstream passover chamber.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is an overall cross-sectional view of an overhang structure shown as the first embodiment.

  The target sewer is a combined sewer that discharges sewage and rainwater through the same pipe, and as shown in FIG. 1 (a), on the upstream and downstream sides of an obstacle 100 such as a river. An upstream sewer 1 and a downstream sewer 2 are provided, and an overpass 10 is provided to connect the sewers 1 and 2 while avoiding the obstacle 100. As means for constituting the overpass portion 10, firstly, vertical shafts 4 and 5 are provided which are communicated with the respective sewers 1 and 2 and are perpendicular to both sides of the obstacle 100.

  The lower part of each vertical shaft 4, 5 is an upstream passover chamber 11 and a downstream passover chamber 12, and the passway between the lower ends of both the passover chambers 11, 12 passes below the obstacle 100. They are connected by a transverse tube 13. The upstream part of the overpassing chamber 11, the downstream side of the overpassing room 12, and the overpassing crossing pipe 13 constitute the overpass part 10.

  Further, at the inner bottom portion of the overpass tube 13 of the overpass portion 10, the exit from the entrance 13 </ b> A of the overpass tube 13 is secured in a state where a sufficient flow path is secured around as shown in FIG. An auxiliary pipe 20 extending to 13B is provided, and the downstream side of the auxiliary pipe 20 is started up in a state where a sufficient flow path is secured in the downstream inside of the downstream passover chamber 12, and the upper end thereof is a discharge port. 21 communicates with the downstream sewer 2.

  Further, a weir 31 for raising the free water surface J1 to be higher than the discharge port 21 of the auxiliary pipe 20 between the discharge port 21 at the upper end of the auxiliary pipe 20 and the free water surface J1 of the sewage in the downstream passover chamber 12. Is provided. As shown in FIG. 2 in an enlarged manner, the weir 31 is located between the discharge port 21 at the upper end of the auxiliary pipe 20 and the free water surface J1 of the sewage in the downstream passway chamber 12, and the free water surface J1 and the discharge port 21. It fulfills the role of ensuring a water level difference H that is greater than or equal to a predetermined value.

  In addition, the pipe diameter of the auxiliary pipe 20 is determined so that the flow rate is higher than the level at which sand does not accumulate on the basis of the flow rate in fine weather. In addition, the height of the weir 31 can surely cause a flow with a flow velocity of a predetermined level or more in the auxiliary pipe 20 due to the water level difference H in clear weather with a small amount of water in consideration of the flow path loss of the auxiliary pipe 20. The level is set.

  On the other hand, the inlet 22 at the upstream end of the auxiliary pipe 20 opens to the inlet 13A from the upstream side depression chamber 11 to the depression crossing pipe 13 in the direction in which sewage flows. In addition, in the upstream side cover chamber 11, a guide wall 41 and an inclined bottom wall 42 are provided as guide means for guiding sand falling in the upstream side cover chamber 11 to the inlet 22 of the auxiliary pipe 20. Is provided.

Next, the operation will be described.
In this overpass structure, the flow path outside the auxiliary pipe 20 disposed in the overpass pipe 13 is connected to the free water surface J1 in the downstream side overpass chamber 12, and The flow path is connected to a discharge port 21 that communicates with the downstream sewer 2. The free water surface J1 of the downstream passover chamber 12 is maintained at a higher level than the discharge port 21 at the upper end of the auxiliary pipe 20 due to the presence of the weir 31, so that the auxiliary connected to the free water surface J1. In order for the sewage to flow through the flow path outside the pipe 20, a water pressure sufficient to overflow the weir 31 is required.

  Since the amount of water is small during fine weather, the water pressure is not generated. Therefore, the sewage does not cross the weir 31 and stops outside the auxiliary pipe 20 in the overpass pipe 13 and in the downstream passover chamber 12. Put in state. On the other hand, the sewage flowing inside the auxiliary pipe 20 does not need to cross the weir 31 and can flow with a small resistance. For this reason, when there is little flowing water like the time of fine weather, only the inside of the auxiliary pipe 20 will flow sewage.

  Since the flow passage cross-sectional area inside the auxiliary pipe 20 is smaller than that of the overpass pipe 13, the flow rate is increased even when the flow rate of the sewage is small, and the solids such as sand do not stay and flow downstream with the sewage. And finally transferred to the downstream sewer 2.

  Further, when it rains, the amount of sewage increases and the flowing water pressure rises beyond the weir 31 so that the sewage flows not only in the auxiliary pipe 20 but also in the entire cross section in the overpass pipe 13. Then, the sewage that has flowed outside the auxiliary pipe 20 overflows the weir 31 in the downstream side overpass chamber 12 and flows into the downstream side sewage channel 2.

  Also in this case, a water level difference H of a predetermined level or more is maintained between the free water surface J1 in the downstream passover chamber 12 and the discharge port 21 of the auxiliary pipe 20 due to the presence of the weir 31. Accordingly, the flow velocity inside the auxiliary tube 20 becomes faster than the flow velocity outside the auxiliary tube 20. Therefore, even if sand has already accumulated in the auxiliary pipe 20, it can be expected that the accumulated sand will be swept away at a high flow rate.

  Further, the discharge port 21 of the auxiliary pipe 20 may be closed by a valve or the like (not shown). In such a case, the flow in the auxiliary pipe 20 can be stopped as necessary, and the overpass pipe The effective cross-sectional area of the flow path in 13 can be reduced by the cross-sectional integral of the auxiliary pipe 20. As a result, the flow velocity in the overpass pipe 13 can be increased, and the discharge of sediment in the pipe can be promoted.

  In addition, the inlet 22 of the auxiliary pipe 20 is opened at the inlet 13A (communication port) from the upstream side depression chamber 11 to the crossover pipe 13 so that the sewage flows in the upstream side. Sands falling together with sewage in the cabin 11 can be guided into the auxiliary pipe 20 having a high pipe flow velocity. In particular, since the guide wall 41 and the inclined bottom wall 42 are provided in the upstream side cover chamber 11, it is possible to effectively prevent sand from staying in the upstream side cover chamber 11.

  As described above, according to the present Futsuetsu part structure, it is possible to automatically and appropriately switch the cross section through which sewage flows in rainy weather and in fine weather according to the small amount of flowing water. Therefore, it is possible to effectively solve the problem of sand accumulation in the crossover pipe 13 when the sewage flow rate is small, and the maintenance interval such as cleaning can be extended.

  Moreover, the configuration is a simple configuration in which the auxiliary pipe 20 is disposed in the range from the inside of the crossover pipe 13 to the downstream side of the overpassage chamber 12 and the weir 31 is provided in the downstream side of the overpassage room 12. Therefore, it can be realized at low cost. In particular, in the case of this overpass structure, since it does not use any means such as a compressor as an air source, a gate for air leakage prevention, or an air bag, it can be easily applied to an existing overpass structure. it can.

FIG. 3 is a cross-sectional view of an overhang structure according to the second embodiment of the present invention.
In this overpass part 10B, the upstream side of the auxiliary pipe 20 is started up in a state where a sufficient flow path is secured around the inside of the upstream side overpassage chamber 11, and the upper end of the auxiliary pipe 20 is set as a suction port 23 on the upstream side. It communicates with waterway 1. And only when the sewage flows at a level higher than a certain level between the suction port 23 at the upper end of the auxiliary pipe 20 and the free water surface J2 of the sewage in the upstream passover chamber 11, the free water surface J2 side is reached. A weir 32 is provided to allow overflow of sewage. Since the other points are completely the same as the overhang structure of the first embodiment shown in FIG.

  According to the cover part structure of this configuration, the upstream side of the auxiliary pipe 20 is raised in the upstream side cover chamber 11, and the upper end of the auxiliary pipe 20 is communicated with the upstream sewer 1 as a suction port 23. Since the weir 32 is provided between the free water surface J2 in the upstream passover chamber 11, the scum can be efficiently sucked into the auxiliary pipe 20 even in fine weather when the amount of flowing water is small. Scum accumulation in the chamber 11 can be effectively prevented.

  The weirs 31 and 32 in each of the above embodiments may be movable up and down so that the height can be changed. If an existing up and down movable weir is installed, divert it. Can do.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram of the depression structure of 1st Embodiment of this invention, (a) is whole sectional drawing, (b) is Ib-Ib arrow sectional drawing of (a). It is an enlarged view of the II section of FIG. It is a block diagram of the depression structure of 2nd Embodiment of this invention, (a) is whole sectional drawing, (b) is a IIIb-IIIb arrow sectional drawing of (a). It is a figure of the overpass part structure incorporating the conventional air cushion siphon system, (a) is a state at the time of normal, (b) is a figure which shows the state at the time of cleaning. It is whole sectional drawing which shows the other example of the conventional depression part structure. It is a whole sectional view showing other examples of the conventional overpass part structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Upstream sewage channel 2 Downstream sewage channel 10, 10B Bushing part 11 Upstream side swaying chamber 12 Downstream swaying chamber 13 Bushing crossing pipe 13A Entrance of a Bushing crossing pipe 13B Outlet of a Bushing crossing pipe 20 Auxiliary pipe 21 Discharge port 22 Inlet 23 Suction port 31, 32 Weir 41 Guide wall (guide means)
42 Inclined bottom wall (guidance means)
100 Obstacle J1, J2 Free water surface

Claims (4)

An upstream and downstream depression chamber connected to an upstream sewer and a downstream sewer, respectively, sandwiched between obstacles and extending below the obstacle; and below the obstacle In the subsidence part structure of the sewer comprising the upper crossing pipe and the lower crossing pipe connecting the lower ends of the downstream passover room,
An auxiliary pipe extending from the entrance to the outlet of the overpass pipe is provided in the inside of the overpass pipe with a sufficient flow path around it, and the downstream side of the auxiliary pipe is connected to the downstream side pipe. Start up with a sufficient flow path around in the interior of the over-room, and let the upper end communicate with the downstream sewer as an outlet,
On the other hand, a sewage surfacing characterized in that a weir is provided between the discharge port at the upper end of the auxiliary pipe and the free water surface of the sewage in the downstream passover chamber, which raises the free water surface higher than the discharge port of the auxiliary pipe. Koshibe structure.   2. The inlet of the upstream end of the auxiliary pipe is opened at a communication port between the upstream side depression chamber and the crossover pipe so as to be directed in a direction in which sewage flows. The sewer part structure of the sewer.   3. The sewer in the sewer according to claim 2, wherein guiding means for guiding sand falling in the upstream side overpass chamber to the entrance of the auxiliary pipe is provided. Part structure. The upstream side of the auxiliary pipe is started up in a state where a sufficient flow path is secured around the inside of the upstream side overpass chamber, and the upper end thereof is communicated with the upstream side sewer as a suction port,
On the other hand, only when sewage flows at a level above a certain level between the suction port at the upper end of the auxiliary pipe and the sewage free water surface in the upstream passover chamber, the sewage overflows to the free water surface side. 2. The sewer overpass structure according to claim 1, further comprising a weir that allows flow.

Images