JP2861823B2 - Deep underground drainage facility - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deep underground drainage facility that collects inflow water such as rainwater into a groundwater channel provided underground through a shaft, pumps it up, and discharges it to rivers and the like. The prevention of inflow of inflow water from shafts to the ground surface.

[0002]

2. Description of the Related Art In recent years, with the growing need for quality improvement of people's lives, there is a growing demand for better living environments. This is one of the requirements for better living space, and the improvement of flood control safety is also included in this requirement. Especially in urban areas, due to the complete paving of roads and the decrease of vacant lots, there is almost no infiltration of rainwater underground, and urban floods where a large amount of rainwater overflows on the surface in a short time are increasing, and the problem is being highlighted. . Therefore, the flood problem in urban areas, where population and assets are becoming more concentrated in terms of social impact, is very large.

[0003] However, there is a problem that land prices soar in urban areas and it is difficult to secure land for pump stations and the like. Therefore, space saving of urban drainage facilities is naturally required to reduce construction costs. However, since the space is saved, the drainage capacity is insufficient just by reducing the scale. Therefore, there is a demand for a small, high-speed drainage accompanying the space saving. Under such a background, a drainage system concept has been born in which drainage is performed using a deep underground about 10 m or more below the ground surface. The deep underground refers to an area under a subway, a sewer, various underground laying, etc. in an urban area.

[0004] The above-mentioned concept is to construct a large underground waterway under a large depth of underground to use for drainage of rainwater.
Deep underground drainage facilities have the advantage of using less underground space in urban areas, as compared to above-ground drainage facilities, and have the advantage of being able to use underground effectively in urban areas. There are advantages.

[0005] As a prior art relating to such a deep underground drainage facility, for example, there is a document "Deep underground drainage drainage pump system turbomachinery, Vol. 21, No. 10, pages 23 to 29".

[0006]

However, in the above prior art, there is little consideration for a rise in the water level in the shaft due to a sudden stop of the pump or a sudden closure of the water shutoff valve, and the inflow water flows back through the shaft, and The problem remains that it may overflow. In addition, there is a problem that it has not yet been able to respond to the problems associated with the miniaturization and high-speed drainage of large depth underground drainage facilities.

Accordingly, an object of the present invention is to suppress the rise in water level in a shaft by optimizing the structure of the shaft, etc.
It is an object of the present invention to provide a deep underground drainage facility for preventing inflow of inflow water from a shaft. It also provides a deep underground drainage facility that can meet the challenges of small, high-speed drainage.

[0008]

The object of the present invention is to provide an underground waterway buried deep underground, a shaft that communicates with the underground waterway and allows inflow water such as rainwater to flow down into the underground waterway, In a deep underground drainage facility consisting of a pumping station that pumps up inflow water and discharges it to rivers, etc. This is achieved by providing a resistor having a large passage resistance at the time.

In the case where there are a plurality of shafts, a plurality of shafts are provided, one of which is the closest shaft to the pumping station.
This can also be achieved by burying a communication member that communicates with an adjacent shaft adjacent to the nearest shaft and allows inflow water in the nearest shaft to flow into the adjacent shaft.

[0010]

According to the above construction, the velocity of water passing through the shaft is inversely proportional to the square root of the resistance. Therefore, the velocity of the water decreases as the resistance increases. For example, when the passage resistance in the case of the reverse flow is six times that in the case of the forward flow, the passage speed of the reverse flow becomes (1 /
(6) Double = 0.41 times. There is no problem in the case of a forward flow in which the inflow water flows down.If the inflow water flows backward, the energy of the inflow water is attenuated, the rise in the water level in the shaft is mitigated, and overflow from the shaft is prevented. Is done.

[0011] The pressure rise due to the sudden stop of the pump or the sudden closing of the water stop valve increases as the position is closer to the pump station. Therefore, the risk of flooding from the shaft is greater for the nearest shaft, which is the shaft closest to the pump station. In the present invention, since the nearest shaft and the adjacent shaft adjacent to the nearest shaft are communicated with each other, when the inflow water rises in the nearest shaft, the inflow water also flows into the adjacent shaft, and the rise in the water level of the nearest shaft is reduced. Is suppressed. This prevents flooding from the shaft.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a deep underground drainage facility according to one embodiment of the present invention. The structure of the deep underground drainage facility is as follows.

As shown in the figure, a groundwater channel 1 is buried deep underground. Through a plurality of shafts 2 communicating with the underground waterway 1, inflow water such as rainwater flowing from a road, a water discharge channel 3, a sewer 4 or the like flows down to the underground waterway 1.
The downstream end of the underground waterway 1 leads to a pumping station 9. The inflow water is collected in a pump station 9. The collected inflow water is pumped by a pump 7 and discharged to a discharge destination river 5 or the like via a discharge pipe 8. In addition to the river 5, there is also a sea or another system of drainage channels.

In the vertical shaft 2, overflow resistance is small when passing water flowing down the vertical shaft 2 is small, and passing resistance is large when flowing backward when the inflow water rises. A resistor 10 is provided as a member.

In such a deep underground drainage facility,
When the pump suddenly stops due to a power failure, or when the water stop valve provided immediately after the pump is suddenly closed, the inflowing water that had been flowing in the direction of the pumping station 9 through the underground waterway 1 was suddenly blocked. Therefore, a large change in flow velocity occurs. Then, the pressure in the underground waterway 1 changes suddenly. This is caused by the inertia of water, also called water hammer, and is a phenomenon in which the pressure rises transiently.

This pressure change differs depending on the flow velocity and location, and is expressed by the following equation.

ΔH = (− L / g) × ΔV (Equation 1) Here, ΔH is the amount of change in pressure, L is the length of the pipeline, g is the gravitational acceleration, and ΔV is the change in the flow velocity. ΔH increases as the speed of blocking the flow increases and as the flow velocity increases. And the pressure change when the flow is blocked
Since the flow is decelerated, ΔV is negative, ΔH is positive, and the pressure increases. When the pressure rises, the water tries to rise,
If there is a shaft nearby, the water level in the shaft rises, and water may overflow from the shaft to the ground surface. In order to prevent this, a resistor 10 is provided in the shaft 2.

The resistor 10 serves to dissipate the energy of the rise in the level of the inflow water due to the water hammer. Since the energy of the inflow water flowing backward in the shaft is attenuated, the rise in the level of the inflow water is reduced, and the overflow of the inflow water from the shaft is prevented. This will be described with reference to the resistor 10 in the present embodiment shown in the next figure. FIG. 2 is a perspective view showing one embodiment of the resistor. FIG. 3 is a diagram showing a resistor element of the resistor shown in FIG. The resistor element 10a includes the resistor 10
Is one of the components. The resistor element 10a is a funnel-shaped member, and water can pass through the center. FIG.
As shown in (1), the resistor 10 is a structure in which a plurality of resistor elements 10a, which are such funnel-shaped members, are overlapped in the same direction.

FIG. 2 shows a forward flow in which the inflow water flows down the shaft 2, that is, a flow flowing down the resistor 10 as a forward flow 12. Further, a reverse flow in which inflow water rises up the shaft 2 reversely, that is, a flow of rising water level is shown as a flow 11 at the time of reverse flow.

In the resistor 10 as shown in FIG.
The flow resistance of the flow 12 at the time of forward flow is small, and the flow resistance of the flow 11 at the time of reverse flow is large. Specifically, when the difference was calculated by the ratio of the resistance coefficients, the ratio between the resistance coefficient at the time of reverse flow and the resistance coefficient at the time of forward flow, that is, the resistance ratio was about 6. Looking at the difference in resistance between the case where the resistor 10 is present and the case where the resistor 10 is not present, assuming that the resistance coefficient when there is no resistor is 1 and the resistance coefficient when the backflow is almost 1 Is six times that when there is no resistance coefficient, and the difference in the resistance can be said to be about six times.

When such a resistor 10 is provided in the shaft 2, as described in the section of the operation, the rising speed of the inflow water on the contrary in the shaft 2 becomes 0.41 times, and the rising speed is increased. Become. The pressure rise that occurs when the pump suddenly stops or the water shutoff valve closes suddenly does not last for a long time,
Since the water level rise is completed in a short time, that is, the water level rise occurs for a short time, the inflow water does not overflow from the shaft if the inflow water does not rise up the shaft during this time. Resistor 10
In the case where there is, since the rising speed is small, a margin time 2.4 times as long as the case where the resistor 10 is not provided is obtained, and the effect of preventing flooding can be obtained.

Therefore, it is desirable that the resistor 10 is installed near the communicating portion between the shaft 2 and the underground waterway 1, that is, at a deep underground portion of the shaft 2. Because if the resistor 10 is near the surface, the influent will quickly reach near the surface, and the influent will quickly flood the surface, regardless of time. Only because the resistor 10 is near the deep underground communication portion, the time for the inflow water to slowly rise and overflow while filling the shaft 2 can be gained, and overflow is prevented.

The resistor 10 having a structure in which the resistor elements 10a, which are funnel-shaped members, as shown in FIG. This is a convenient structure.

On the other hand, the pressure change ΔH varies depending on the location and the decay time, but the length L of the pipeline in the equation (1), that is,
It depends on the length of the underground waterway 1 up to the pump station 9. Therefore, the pressure change ΔH becomes closer to the pump station 9.
Is big. That is, the pressure rise in the shaft near the pumping station 9 is the largest, and the water level is most likely to rise.

According to this fact, when there are a plurality of shafts 2 and each of the shafts 2 is provided with the resistor 10, the resistance (including the resistance ratio and the resistance coefficient) of the installed resistor 10 when flowing backward is included.
It is reasonable to make the shaft 2 larger as the shaft 2 is closer to the pumping station 9.

In other words, when a plurality of shafts 2 communicate with the groundwater channel 1, the passage resistance at the time of backflow is increased in inverse proportion to the length of the groundwater channel 1 between the shaft 1 and the pumping station 9. The resistor 10 is installed in the shaft 1. This leads to efficient flood prevention. For example, as shown in FIG. 1, although it is a little difficult to understand, the number of resistor elements 10 a of the shaft 2 near the pumping station 9 is three, and the number of resistor elements 10 a of the shaft 2 away from the pumping station 9 is two. I do.

As described above, all the resistors 10 do not necessarily have to have the same dimensions and the same resistance, and the resistors 10 of the shaft 2 remote from the pumping station 9 have low resistance and are inexpensive. It may be made. In some cases, the resistor 10 need not be provided.

By the way, as in the present embodiment, the shaft 2 and the resistor 10 are separated from each other, the resistor 10 is manufactured at a factory, and the resistor 10 is brought to the site and incorporated into the main body of the shaft 2. Conceivable. The resistor 10 is manufactured in advance at another location as a component of a deep underground drainage facility, and by adopting a method of incorporating the same into a shaft, the construction cost of the drainage facility can be reduced and the construction period can be shortened. It is possible to reduce the total construction cost. If separate, the resistor 10 can be standardized, leading to cost reduction. In other words, it is possible to provide an inexpensive deep underground drainage facility with flood prevention. However, in a small-scale drainage facility, the shaft 2 and the resistor 10 may be integrated.

FIGS. 4 and 5 are sectional views showing another embodiment of the resistor. FIG. 4 is a view taken along the line XX of FIG. 5, and FIG. 5 is a view taken along the line YY of FIG. 4 and 5, a resistor 18, a flow 12 at the time of forward flow, and a flow 11 at the time of reverse flow
As shown.

The resistor 18 serving as a flood prevention member generates a backward swirling flow that swirls and flows only when the inflow water is backflowing, and has a complicated operating characteristic in which the passage resistance at the time of backflow is greater than at the time of backflow. It is made of a backflow swirling structure having a flow path. That is, the flow 12 at the time of the forward flow in which the inflow water flows down the resistor 18 is an orderly natural flow according to gravity even if the flow path is somewhat complicated. Conversely, the flow 11 at the time of reverse flow in which the inflow water rises up the resistor 18 is guided by the side wall of the swirl chamber 28 and swirled. Therefore, the inflow water stays in the swirl chamber 28 for a long time, and does not easily flow out of the swirl chamber 28. That is, it is difficult to flow at the time of reverse flow, and the passage resistance becomes large.

The resistance ratio of the resistor 18 is about 10.
In this embodiment, although the structure is more complicated than that of the above-described resistor 10, the resistance ratio is large, and there is an effect that the purpose of preventing overflow is more efficiently exhibited.

As shown in FIG. 4 and FIG. 5, the resistor 18 made of a backflow swirling type structure in which the swirling chamber 28 is vertically installed and which makes good use of gravity occupies a dimension in the height direction. Therefore, it is suitable for communicating with the shaft 2 that is buried underground at a large depth and is long in the depth direction. In other words, the vertical type resistor 18 can be said to be a flood prevention member suitable for deep underground drainage facilities.

FIG. 6 is a sectional view showing another embodiment of the resistor. The configuration of the resistor has been increased in size and is shown in the overall sectional view of the deep underground drainage facility.
FIG. 7 is a view taken along the line ZZ in FIG.

In FIG. 6, a control flow introduction pipe 2
5, a resistor 24 as a flood prevention member having a control flow 26, a control flow control valve 27, a swirl chamber 28 and the like is provided. The resistor 24 is another type of the above-described structure of the backflow swirling type, and the swirling chamber is of a horizontal type.

The operation will be described with reference to FIGS. 6 and 7. Using the pressure of the water hammer generated in the underground waterway 1,
The control flow 26 is introduced from the control flow introduction pipe 25 and the resistor 24
A swirling flow is generated in the swirling chamber 28 of the above. At this time, the control flow 26 is transmitted to the underground waterway 1 on the side near the pumping station 9.
Is introduced from the control flow introduction pipe 25 connected to the control flow. This is because the pressure change ΔH on the side close to the underground waterway 1 pumping station 9 is large, and the control flow 26 which is a strong jet is obtained. In other words, when the swirl chamber of the structure of the backflow swirl flow type is a horizontal type, an introduction pipe for guiding the jet generated by the pressure difference in the underground water channel to the swirl chamber is provided.

As a result, a backflow swirling flow that swirls and flows only when the inflow water is backflow is obtained, the passage resistance at the time of backflow is larger than at the time of forward flow, and the rising speed of the water level is suppressed. still,
A throttle section is provided in the upper opening of the swirl chamber 28 to increase the passage resistance at the time of backflow.

Although the structure of the resistor 24 is also complicated, a desired resistance ratio can be obtained by controlling the control flow control valve 27 provided in the middle of the control flow introduction pipe 25, and the structure of the drainage facility can be obtained. This has the effect that the water level rising speed can be adjusted without any change.

FIG. 8 is a sectional view showing a deep underground drainage facility according to another embodiment of the present invention. This is an example of installing a resistor in a pump well of a deep underground drainage facility including a pump well.

In this embodiment, the underground waterway 1, the shaft 2, the pump well 30, the suction gate 33, the water stop valve 34, the discharge gate 3
5, a resistor 36 and the like.

In this embodiment, the overflow preventing member is a resistor 3
6. The resistor 36 installed in the pump well 30 is shown in FIG.
It is clear that the same effect as described above can be obtained, and the description of the operation is omitted. Therefore, the pump well 30 is defined as one type of the shaft 2.

The resistors 10, 1 including the resistor 36
The dimensional shape, resistance characteristics, installation position, and the like of 8, 24, etc. should be selected to optimal values according to the operation and environmental conditions of each drainage facility.

FIG. 9 is a sectional view showing a deep underground drainage facility according to another embodiment of the present invention.

In this embodiment, shafts are connected underground. That is, the nearest shaft 2a, which is the closest shaft to the pump station 9, and the adjacent shaft 2, which is the shaft adjacent thereto,
b is communicated with a communication pipe 37 as a communication member. When the water level in the nearest shaft 2a, which is closest to the pumping station 9 and has a high pressure rise, rises due to the communication, the inflow water flows into the adjacent shaft 2b, and the rise in the water level in the nearest shaft 2a is reduced. Is done. This prevents flooding from the shaft.

In this embodiment, there is an advantage that there is no complicated structure in the shaft, and there is an effect that the maintenance is easy. And because of the ease of maintenance, communication pipes are suitable for burying deep underground where land can be effectively used. Therefore, a plurality of communication pipes can be connected to a plurality of shafts in a row.

As other communication members, there are culverts, horizontal shafts and the like in addition to the communication pipes. These communication members are all included in the overflow prevention member. Further, as shown in the figure, the communication pipe 37 may be buried in an inclined state. In this case, it is preferable that the inclination is lowered from the nearest shaft 2a to the adjacent shaft 2b, and the gravity is used well.

Further, the number of communication pipes, installation positions, dimensions and shapes are designed for each drainage facility and for each shaft. In addition, the combined use of the communication pipe 37 or the like and the resistor 10 or the like is an effective method in some cases.

On the other hand, in the above embodiment, two types of relatively inexpensive and easy-to-install overflow prevention members have been described. It is also possible to use, as the overflow preventing member, one configured of closing means for closing the shaft based on the detecting means. The closing means includes a closing valve, a closing gate, a closing weir and the like.

Further, a method for preventing overflowing is also conceivable in which a water storage chamber for temporarily storing inflowing water flowing backward is connected to a shaft. If you draw a cross section, the middle of the shaft will be bulging. Such a water storage chamber is also an example of the overflow prevention member.

[0049]

According to the present invention, there is an effect that a rise in water level in a shaft of a deep underground drainage facility is suppressed, and overflow from the shaft is prevented. In addition, there is an effect that it is possible to respond to a severe water hammer problem associated with miniaturized high-speed drainage.

Therefore, it is possible to effectively utilize the land in the urban area and realize a drainage facility free from anxiety.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a deep underground drainage facility according to an embodiment of the present invention.

FIG. 2 is a perspective view showing one embodiment of a resistor.

FIG. 3 is a view showing a resistor element of the resistor shown in FIG. 2;

FIG. 4 is a sectional view showing another embodiment of the resistor.

FIG. 5 is a view as seen in the direction of arrows Y in FIG. 4;

FIG. 6 is a sectional view showing another embodiment of the resistor.

FIG. 7 is a view taken in the direction of arrows ZZ in FIG. 6;

FIG. 8 is a sectional view showing a deep underground drainage facility according to another embodiment of the present invention.

FIG. 9 is a sectional view showing a deep underground drainage facility according to another embodiment of the present invention.

[Explanation of symbols]

1 ... groundwater channel, 2 ... shaft, 3 ... drainage channel, 4 ... sewer, 5 ...
River, 7 ... Pump, 8 ... Discharge line, 9 ... Pump station, 1
0, 18, 24, 36 ... resistor, 10a ... resistor element,
11: Flow at the time of reverse flow, 12: Flow at the time of forward flow, 25: Control flow introduction pipe, 26: Control flow, 27: Control flow control valve, 28 ...
Swirling chamber, 30 pump well, 33 suction gate, 34 shutoff valve, 35 discharge gate, 37 communication pipe, 2a nearest pit, 2b adjacent pit.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-363427 (JP, A) JP-A-5-287779 (JP, A) JP-A-5-214761 (JP, A) 222760 (JP, A) Japanese Utility Model 1983-156732 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) E03F 1/00 E03F 5/22

Claims (10)

(57) [Claims] An underground waterway buried underground at a large depth, a shaft that communicates with the underground waterway and allows inflow water such as rainwater to flow down into the underground waterway, and a pump that pumps the inflow water flowing down and assembled into the underground waterway. In a deep underground drainage facility composed of a pumping station that pumps up and drains water into rivers, etc., in the vertical shaft, the passing resistance of the inflow water flowing down the vertical shaft is small, A deep underground drainage facility characterized by the installation of a resistor with a high passage resistance. 2. The underground waterway according to claim 1, wherein when the plurality of shafts communicate with the underground waterway, the passage resistance at the time of the backflow is inversely proportional to the length of the underground waterway between the shaft and the pumping station. A deep underground drainage facility, wherein the enlarged resistor is installed in the shaft. 3. The deep underground drainage facility according to claim 1, wherein the resistor is installed near a communication portion between the shaft and the underground waterway. 4. The deep underground drainage facility according to claim 1, wherein the resistor has a structure in which funnel-shaped members are overlapped. 5. The deep underground drainage facility according to claim 1, wherein the resistor is a backflow swirling type structure that swirls and flows only when the inflow water is backflowing. 6. An inlet pipe for guiding a jet generated by a pressure difference in the underground water channel to the swirl chamber, wherein the swirl chamber of the backflow swirl type structure is a horizontal type. A deep underground drainage facility characterized by: 7. An underground waterway buried deep underground, a plurality of shafts communicating with the underground waterway and flowing down inflow water such as rainwater into the underground waterway, and the inflow water flowing down and gathering into the underground waterway. Deep underground drainage facility comprising a pumping station that pumps water and drains it to a river or the like, among the plurality of shafts, a nearest shaft that is the shaft closest to the pumping station, and the nearest shaft. A deep underground drainage facility characterized by burying a communication member that communicates with an adjacent vertical shaft adjacent to a vertical shaft and allows the inflow water in the nearest vertical shaft to flow into the adjacent vertical shaft. 8. A resistor used in the deep underground drainage facility according to claim 1. 9. A communication member used for the deep underground drainage facility according to claim 7. 10. A rainwater which is caused to flow down into the underground waterway through a shaft due to a water hammer generated in an underground waterway buried deep underground due to a sudden stop of a pump installed at a pump station. A deep underground drainage facility characterized in that the inflow of inflow water, etc., flows backward through the shaft and overflows to the surface by burying a flood prevention member at a deep underground portion of the shaft, and Overflow prevention method.