JPH0893040A - Deep underground drainage facility - Google Patents

Abstract

PURPOSE: To provide a deep underground drainage facility which can economically prevent the influx water from overflowing from pits, by installing an overflow preventive member in each pit. CONSTITUTION: An underground water channel 1 is buried deeply underground, and into this water channel 1, influx water such as rainwater from roads, discharge channel 3, pipe conduit 4, etc., flows down via a plurality of pits 2. The downstream end of the water channel 1 leads to a pumping yard 9, and thereto the influx water is gathered. Then the water is lifted by a pump 7. passed through a discharge pipeline 8, and exhausted to a river 5, etc., as destination. Each pit 2 is provided with a resisting body 10 as an overflow preventive member which exerts a small passage resistance to the influx water, when it flows regularly down in the pit 2, and a large passage resistance when the water flows conversely upward.

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 for collecting inflow water such as rainwater into a groundwater channel provided underground through a shaft, pumping it up and discharging it into a river, etc. , Preventing the inflow of inflow water from the shaft to the surface.

[0002]

2. Description of the Related Art In recent years, as the needs for improving the quality of life of the people have increased, it has been further desired to improve the living environment. Demand for better living space is one of these requirements, and improvement of flood control safety is also included in this requirement. Especially in urban areas, due to the complete paving of roads and the reduction of vacant land, there is almost no infiltration of rainwater underground, and urban floods in which a large amount of rainwater overflows on the ground surface in a short period of time are increasing. . Therefore, the flood problem in urban areas where population and assets are concentrated is very large in view of social impact.

However, in urban areas, land prices are soaring that it is difficult to secure land for pumping stations and the like. Therefore, of course, due to the reduction in construction costs, it is required to save space in urban drainage facilities. However, as the space is saved, the drainage capacity becomes insufficient if the scale is reduced. Therefore, there is a demand for a small and high-speed drainage due to the space saving. Against this background, the concept of a drainage system was born in which drainage is performed using a deep underground, approximately 10 m below the surface of the earth or more. In addition, deep underground refers to the parts below the subways, sewers, and various underground layings in urban areas.

[0004] The above concept is to construct a large underground waterway underground at a great depth to make use of it for draining rainwater.
Compared with above-ground drainage facilities, deep-drainage drainage facilities have the advantage that they require less space above ground and can effectively use underground in urban areas. There are advantages.

As a conventional technique 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, pp. 23 to 29".

[0006]

However, in the above-mentioned prior art, there is little consideration for the rise of the water level in the shaft due to the sudden stop of the pump and the sudden closing of the water shutoff valve, and the inflow water flows back through the shaft and There is still the problem that it may overflow. In addition, there is a problem that the problems associated with the miniaturization and high-speed drainage of deep underground drainage facilities have not yet been met.

Therefore, the object of the present invention is to suppress the rise of water level in the shaft by optimizing the structure of the shaft,
It is to provide a deep underground drainage facility that prevents overflow of inflow water from the vertical shaft. In addition, we will provide deep underground drainage facilities that can meet the challenges of small, high-speed drainage.

[0008]

[Means for Solving the Problems] The above-mentioned object is to provide a groundwater channel buried deep underground, a vertical shaft that communicates with the groundwater channel and allows inflow water such as rainwater to flow down to the groundwater channel, and a downflow channel to the groundwater channel. In a deep underground drainage facility composed of a pumping station that pumps up the inflow water by a pump and drains it to rivers, etc., the passage resistance during forward flow when the inflow water flows down the shaft is small, and the reverse flow is rising. This is achieved by providing a resistor having a high passage resistance.

When there are a plurality of vertical shafts, among the plurality of vertical shafts, the nearest vertical shaft which is the vertical shaft closest to the pumping station,
This can also be achieved by communicating with an adjacent vertical shaft adjacent to the closest vertical shaft and burying a communication member for causing the inflow water in the vertical vertical shaft to flow into the adjacent vertical shaft.

[0010]

With the above construction, the speed of water passing through the shaft is inversely proportional to the square root of the resistance, so that the higher the resistance, the lower the speed of water. For example, when the passage resistance in the reverse flow is 6 times that in the forward flow, the passage speed of the reverse flow is (1 /
√6) times = 0.41 times. When the inflow water flows down, there is no problem, and when the inflow water flows backward, the energy of the inflow water is attenuated, the rise of the water level in the vertical shaft is mitigated, and the overflow of the vertical shaft is prevented. To be done.

Further, the pressure increase due to the sudden stop of the pump and the sudden closing of the water shutoff valve is greater as the pump station is closer. Therefore, the danger of flooding from the shaft is greater than that of the nearest shaft, which is the shaft located closest to the pumping station. In the present invention, since the most adjacent vertical shaft and the adjacent vertical shaft adjacent to the most vertical shaft are communicated with each other, when the inflow water rises in the most vertical shaft, the inflow water also flows into the adjacent vertical shaft, and the water level rise of the most vertical shaft. 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 an 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 this groundwater channel 1, inflow water such as rainwater flowing from a road, a discharge channel 3, a pipe 4 or the like flows down to the ground channel 1.
The downstream end of the underground waterway 1 leads to the pumping station 9. The inflow water is collected at the pump station 9. The collected inflow water is pumped up by the pump 7 and discharged through the discharge pipe 8 to the discharge destination river 5 or the like. In addition to river 5, there is also a sea and another system of spillway.

Further, the passage resistance to the vertical shaft 2 is small when the inflow water is flowing down the vertical shaft 2, and the passage resistance is large when the inflow water is reversely rising. A resistor 10 as a member is provided.

In such a deep underground drainage facility,
When the pump suddenly stops due to a power outage or the stop valve installed immediately after the pump is suddenly closed, the inflow water that had been flowing through the underground waterway 1 in the direction of the pump station 9 until then is suddenly stopped. Therefore, a large change in flow velocity occurs. Then, the pressure in the groundwater channel 1 suddenly changes. This is due to the inertial force of water, also called a water hammer, which is a phenomenon in which the pressure rises transiently.

This pressure change depends on the flow velocity and the location and is expressed by the following equation.

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

The resistor 10 dissipates the energy of rising the water level of the inflow water due to a water hammer. Since the energy of the inflow water that has flowed back in the vertical shaft is attenuated, the rise in the level of the inflow water is mitigated, and the overflow of the inflow water from the vertical shaft is prevented. This will be described with reference to the resistor 10 in this embodiment shown in the next figure. FIG. 2 is a perspective view showing an embodiment of the resistor. FIG. 3 is a diagram showing resistor elements of the resistor shown in FIG. The resistor element 10a is the resistor 10
Is one of the constituent elements of. The resistor element 10a is a funnel-shaped member, and water can pass through the center thereof. Figure 2
As shown in, the resistor 10 is a structure in which a plurality of resistor elements 10a, which are funnel-shaped members, are stacked in the same direction.

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

In the resistor 10 as shown in FIG. 2,
The passage resistance of the flow 12 at the time of forward flow is small, and the passage resistance of the flow 11 at the time of reverse flow is large. Specifically, when the difference between them was calculated by the ratio of the resistance coefficients, the ratio of the resistance coefficient during the backward flow and the resistance coefficient during the forward flow, that is, the resistance ratio was about 6. Looking at the difference in resistance between when the resistor 10 is present and when the resistor 10 is absent, assuming that the resistance coefficient when the resistor is not present is 1 and the resistance coefficient when the backflow is also approximately 1, Since the coefficient of resistance is 6 times that when there is no, the difference in resistance can also be said to be about 6 times.

When such a resistor 10 is provided in the vertical shaft 2, as described in the section of action, the rising speed of the inflow water which rises in the vertical shaft 2 is 0.41 times, and the rising speed is slow. Become. And the pressure increase that occurs when the pump suddenly stops or the water shutoff valve suddenly closes does not last for a long time,
Since it ends in a short time, that is, the water level rises for a short time, if the inflow water does not rise up the shaft within this time, the inflow water will not overflow from the shaft. Resistor 10
If there is, the rise speed is small, so that a margin time of 2.4 times is obtained as compared with the case where the resistor 10 is not provided, and the effect of preventing flooding is obtained.

Therefore, it is desirable that the resistor 10 is installed in the vicinity of the communicating portion between the shaft 2 and the underground waterway 1, that is, in the deep underground part of the shaft 2. Because, when the resistor 10 is near the surface of the earth, the inflow water reaches the surface of the earth in a blink of an eye, and the inflow of water immediately overflows to the surface of the earth regardless of the margin time. Since the resistor 10 is near the deep underground communication part, it takes time for the inflow water to slowly rise and overflow while filling the shaft 2, thus preventing overflow.

In addition, the resistor 10 having a structure in which the resistor elements 10a, which are funnel-shaped members, are superposed as shown in FIG. It is a convenient structure because it exists.

On the other hand, the pressure change ΔH varies depending on the place and the decay time, but the length L of the pipe line of the formula (1), that is,
It depends on the length of the underground waterway 1 to the pump station 9. Therefore, the closer to the pump station 9, the pressure change ΔH
Is big. That is, the pressure rise in the vertical shaft closest to the pumping station 9 is the largest, and the water level is most likely to rise.

From this fact, when there are a plurality of vertical shafts 2 and each of the vertical shafts 2 is provided with a resistor 10, the resistance of the installed resistor 10 during reverse flow (including resistance ratio and resistance coefficient)
It is rational 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 during 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 will be installed in the vertical shaft 1. This leads to efficient flooding prevention. For example, although it is a little difficult to understand, as shown in FIG. 1, the vertical shaft 2 near the pumping station 9 has three resistor elements 10a, and the vertical shaft 2 away from the pumping station 9 has two resistor elements 10a. To do.

As described above, all the resistors 10 do not necessarily have the same size and the same resistance, and the resistors 10 of the shaft 2 separated from the pumping station 9 have a small resistance and are inexpensive in price. It can be made. In some cases, the resistor 10 may not be installed.

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

4 and 5 are sectional views showing other embodiments of the resistor. 4 is a view on arrow XX in FIG. 5, and FIG. 5 is a view on arrow YY in FIG. 4 and 5, the resistor 18, the forward flow 12 and the reverse flow 11
Is shown as.

The resistor 18 as the overflow preventing member has a complicated operating characteristic that a countercurrent swirl flow is generated which swirls and flows only when the inflow water is in the reverse flow, and the passage resistance in the reverse flow is larger than in the forward flow. It is made of a reverse flow swirl flow type structure having a flow path. That is, the flow 12 when the inflow water flows down the resistor 18 in a forward flow is an orderly natural flow according to gravity even if the flow path is somewhat complicated. On the contrary, the flow 11 at the time of the 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 for the backflow to flow and the passage resistance becomes large.

The resistance ratio of the resistor 18 is about 10.
In this embodiment, the structure is more complicated than that of the resistor 10 described above, but the resistance ratio is large, and the effect of preventing flooding is exerted more efficiently.

As shown in FIGS. 4 and 5, the resistor 18, which is a counterflow swirl flow type structure in which the swirl chamber 28 is vertically arranged and which utilizes gravity effectively, occupies a dimension in the height direction. Therefore, it is suitable for communicating with the vertical shaft 2 which is just buried deep under the ground and is long in the depth direction. In other words, the vertical type resistor 18 can be said to be an overflow prevention member suitable for a deep underground drainage facility.

FIG. 6 is a sectional view showing another embodiment of the resistor. The structure of the resistor, which is larger in scale, is shown in an overall cross-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 is provided in a vertical shaft 2.
5, a control flow 26, a control flow control valve 27, a swirl chamber 28, and the like, and a resistor 24 as a flooding prevention member are provided. The resistor 24 is another type of the above-described reverse-flow swirl flow type structure, and the swirl chamber is of a horizontal type.

The operation will be described with reference to FIGS. 6 and 7 at the same time. Utilizing 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
The swirl flow is generated in the swirl chamber 28. At this time, the control flow 26 flows into the underground waterway 1 near the pump station 9.
It is introduced from the control flow introducing pipe 25 which is communicated with This is because the pressure change ΔH on the side close to the groundwater channel 1 pumping station 9 is large, and the control flow 26 that is a strong jet flow is obtained. In other words, when the swirl chamber of the counter-flow swirl flow type structure is of a horizontal type, an introduction pipe for guiding the jet flow generated by the pressure difference in the underground waterway to the swirl chamber is provided.

As a result, a reverse flow swirl flow that swirls and flows only when the inflow water is in the reverse flow is obtained, the passage resistance in the reverse flow becomes larger than in the forward flow, and the water level rising speed is suppressed. still,
A throttling portion is provided in the upper opening of the swirl chamber 28 to increase the passage resistance during reverse flow.

Although the resistor 24 has a complicated structure, a desired resistance ratio can be obtained by controlling the control flow control valve 27 installed in the middle of the control flow introducing pipe 25, and the drainage facility structure It has the effect that the water level rise rate can be controlled without change.

FIG. 8 is a sectional view showing a deep underground drainage facility of another embodiment according to the present invention. This is an example of installing a resistor in the pump well of the deep underground drainage facility including the 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, and the discharge gate 3 are provided.
5, resistor 36 and the like.

The overflow preventing member in this embodiment is the resistor 3
It is 6. The resistor 36 installed in the pump well 30 is shown in FIG.
It is obvious that the same effect as the above is exerted, and the explanation 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 are included.
The size and shape of 8, 24, etc., the resistance characteristics, the installation position, etc. should be selected to the optimum value according to the operation of each drainage facility and the environmental conditions.

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 to each other underground. That is, the nearest vertical shaft 2a which is the vertical shaft closest to the pumping station 9 and the adjacent vertical shaft 2 which is the vertical shaft adjacent to it.
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 rises, the inflow water flows into the adjacent shaft 2b by the communication, and the water level rise in the nearest shaft 2a is reduced. To be done. This prevents flooding from the shaft.

In the case of this embodiment, there is an advantage that there is no complicated structure in the shaft, and there is an effect that maintenance is easy. And since the maintenance is easy, the communication pipe is suitable for burying in the deep underground where the land can be effectively utilized. Therefore, it is possible to connect a plurality of communication pipes in a row to a plurality of shafts.

Other communication members include an underdrain, a horizontal shaft, etc. in addition to the communication pipe. All of these communication members are included in the overflow prevention member. Further, as shown in the drawing, the communication pipe 37 may be embedded while being inclined. In this case, it is preferable to make the slope descending from the nearest vertical shaft 2a to the adjacent vertical shaft 2b and to make good use of gravity.

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

On the other hand, in the above-mentioned embodiment, two kinds of relatively inexpensive and easy-to-install flood preventive members have been described. For example, a detecting means for detecting a sudden stop of a pump or a sudden closure of a water shutoff valve and It is also possible to use, as the overflow preventing member, a member configured by a closing unit that closes the vertical shaft based on the detection unit. Examples of the closing means include a closing valve, a closing gate, a closing weir and the like.

Another possible method is to prevent flooding by connecting a water storage chamber for temporarily storing the backflowing inflow water to a vertical shaft. If you draw a cross section, it will be a shape that the middle of the shaft is inflated. Such a water storage chamber is also an example of the overflow prevention member.

[0049]

EFFECTS OF THE INVENTION According to the present invention, there is an effect that the rise of the water level in the shaft of the deep underground drainage facility is suppressed and the overflow of water from the shaft is prevented. In addition, it is also effective in meeting the severe water hammer problems that accompany small high-speed drainage.

Therefore, it is possible to realize effective utilization of land in urban areas and drainage facilities without concern.

[Brief description of 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 an example of a resistor.

FIG. 3 is a diagram showing resistor elements of the resistor shown in FIG.

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

5 is a view taken along the line YY of FIG.

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

FIG. 7 is a view taken along the line ZZ in FIG.

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

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

[Explanation of symbols]

1 ... ground water channel, 2 ... vertical shaft, 3 ... water discharge channel, 4 ... pipe, 5 ...
Rivers, 7 ... Pumps, 8 ... Discharge pipelines, 9 ... Pump stations, 1
0, 18, 24, 36 ... Resistors, 10a ... Resistor elements,
11 ... Backflow flow, 12 ... 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 ... Water stop valve, 35 ... Discharge gate, 37 ... Communication pipe, 2a ... Nearest shaft, 2b ... Adjacent shaft.

Claims (10)

[Claims] 1. A deep underground underground water channel, a vertical shaft that communicates with the underground water channel and causes inflow water such as rainwater to flow down to the underground water channel, and a pump for the inflow water that flows down and gathers into the ground water channel. In a deep underground drainage facility configured with a pumping station pumped by and drained to a river, etc., in the vertical shaft, the passage resistance during forward flow when the inflow water flows down the vertical shaft is small, A deep underground drainage facility that is equipped with a resistor with high passage resistance. 2. In claim 1, when a plurality of said shafts communicate with said groundwater channel, the passage resistance at the time of said reverse flow is inversely proportional to the length of said groundwater channel between said shaft and said pumping station. A large-depth underground drainage facility, characterized in that the enlarged resistor is installed in the shaft. 3. The deep underground drainage facility according to claim 1, wherein the resistor is installed in the vicinity of a communicating portion between the shaft and the underground waterway. 4. The deep underground drainage facility according to claim 1, wherein the resistor is a structure in which funnel-shaped members are stacked. 5. The deep underground drainage facility according to claim 1, wherein the resistor is a reverse flow swirl flow type structure that swirls and flows only when the inflow water is in reverse flow. 6. The inlet pipe for guiding a jet flow generated by a pressure difference in the ground water channel to the swirl chamber when the swirl chamber of the reverse flow swirl type structure is a horizontal type in claim 5. This is a deep underground drainage facility. 7. An underground waterway buried deep underground, a plurality of vertical shafts communicating with the underground waterway and allowing inflow water such as rainwater to flow down into the underground waterway, and the inflow water flowing down and assembled into the underground waterway. In a deep underground drainage facility composed of a pumping station for pumping up the water and draining it to a river, etc., among the plurality of vertical shafts, the nearest vertical shaft which is the vertical shaft closest to the pumping power station, and the nearest vertical shaft. The deep underground drainage facility is characterized in that a communication member is buried so as to communicate with the adjacent vertical shaft adjacent to the adjacent vertical shaft and to cause 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 for use in the deep underground drainage facility according to claim 7. 10. Rainwater caused to flow into a groundwater channel through a vertical shaft due to a water hammer generated in a groundwater channel buried deep underground due to sudden stoppage of a pump installed at a pump station. Inflow of water such as backflow through the vertical shaft and overflowing to the surface of the ground, by embedding an overflow prevention member in the large-depth underground portion of the vertical shaft, the deep-deep underground drainage facility characterized by preventing it. Overflow prevention method.