JP2005055376A - Flow velocity measuring system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately grasp a flow velocity in real time even in floodwater. <P>SOLUTION: A flow velocity measuring system 1 concerned in the present invention is constituted mainly of an earth pressure gauge 3 of a water pressure measuring means and a pore water pressure gauge 4 of a static pressure measuring means attached to a bridge pier 2 of a bridge 12 installed in a river bottom, a radio equipment 5 of a transmission means, a processor 8 and a memory 9 incorporated in a personal computer 7 installed in a river control office 6 built in the vicinity of the river 12, and a liquid crystal monitor 10 of an output means. The processor 8 calculates a water level of a river based on static pressure, reads out a water flow cross-section corresponding to the water level from the memory 9, and calculates a flow rate, using the read-out water flow cross-section and a flow velocity. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a flow velocity measurement system used when measuring the flow velocity and flow rate of a river.

  In managing rivers, it is important to accurately grasp the flow rate of rivers from the viewpoint of water use and flood control. However, since the flow rate varies depending on the weather, etc. It is necessary to measure the flow velocity and water level.

  Conventionally, when measuring the flow velocity of a river, under normal circumstances, when water flows through a magnetic field using a rotary anemometer that obtains the flow velocity from the rotation speed of the blades caused by the flow of water or Faraday's law of electromagnetic induction This was done using an electromagnetic anemometer or the like that obtains the flow velocity from the electromotive force generated in the circuit.

  However, in these measurement methods, the anemometer is inserted directly into the water and the measurement is performed. Therefore, during floods where the flow of the river becomes intense and many obstacles such as driftwood and trash flow down, the anemometer is placed in the water. Measurement after insertion was difficult.

  Therefore, at the time of flooding, the observer measured the flow velocity by a method based on floating observation, in which the floating velocity was calculated by dropping the float from the bridge or the like into the river and measuring the time that the floating float traveled a predetermined distance. .

JP 2002-214246 A JP 2001-343266 A Japanese Patent Laid-Open No. 7-5188

  However, the observation of flow velocity by floats requires specialized observers and cannot perform continuous measurements in real time, especially when the observers arrive at the measurement site during the initial stage of floods. The problem was that data collection was difficult due to the time required.

  In addition, due to the measurement by the observer, a human error occurs, and there is a problem that the error may increase due to drift or the like, and the float does not flow straight.

  On the other hand, in recent years, measuring instruments such as radio wave velocimeters and ultrasonic velocimeters that measure flow velocity using the Doppler effect, and PIV and optical flow velocimeters that measure flow velocity using image processing are directly used in water. Non-contact type velocimeters that measure without being inserted into the tube have also been used, but since non-contact type velocimeters can only obtain surface flow velocity, the average flow velocity must be accurately determined. In addition, since the surface flow velocity is easily affected by wind, there is a problem that correction is necessary to remove such influence.

  Furthermore, the anemometer using the image processing has a problem that illumination is necessary for measurement at night, and measurement may not be possible in fog or heavy rain at night.

  The present invention has been made in consideration of the above-described circumstances, and an object of the present invention is to provide a flow velocity measurement system that can accurately grasp a flow velocity in real time even during a flood.

  In order to achieve the above object, a flow velocity measuring system according to the present invention is attached to an upstream peripheral surface of a bridge pier standing on a river bottom, and measures water pressure at the attachment position. A hydrostatic pressure measuring means, a hydrostatic pressure measuring means for measuring the hydrostatic pressure at the mounting position, the hydrostatic pressure measuring means being mounted on the peripheral surface of the pier and having the same depth as the hydrostatic pressure measuring means; Transmitting means for transmitting measurement data, and an arithmetic processing unit for calculating a flowing water pressure from the difference between the water pressure and the hydrostatic pressure and calculating a flow velocity from the flowing water pressure.

  In the flow velocity measuring system according to the present invention, the arithmetic processing unit is configured to calculate the water level of the river from the hydrostatic pressure.

  In addition, the flow velocity measurement system according to the present invention includes a storage device that stores a flowing water cross-sectional shape or a flowing water cross-sectional area at an arbitrary water level of the river, and the arithmetic processing device includes the flowing water corresponding to the calculated water level. The flow rate is calculated using the flowing water cross-sectional shape or flowing water cross-sectional area and the flow velocity read out from the storage device while reading the cross-sectional shape or flowing water cross-sectional area from the storage device.

  In the flow velocity measuring system according to the present invention, the water pressure measuring means is a soil pressure gauge, and the hydrostatic pressure measuring means is a pore water pressure gauge.

  In the flow velocity measurement system according to the present invention, first, the water pressure at the attachment position is measured by the water pressure measuring means attached to the upstream peripheral surface of the pier standing on the river bottom, and the water pressure at the peripheral surface of the pier is The hydrostatic pressure at the mounting position is measured by the hydrostatic pressure measuring means attached so as to have the same depth as the measuring means.

  Next, the measurement data of the water pressure and the hydrostatic pressure are transmitted to the arithmetic processing device by the transmission means.

  Next, the flowing water pressure is calculated from the difference between the water pressure and the hydrostatic pressure by the arithmetic processing unit, and the flow velocity is calculated from the flowing water pressure.

  In this way, automatic measurement of water pressure and hydrostatic pressure becomes possible, and the flow velocity of the river can be accurately grasped in real time even during a flood.

  The number of the water pressure measuring means and the hydrostatic pressure measuring means is arbitrary. For example, a plurality of water pressure measuring means and a hydrostatic pressure measuring means may be installed in the vertical direction at different depths. It doesn't matter if you do. Since rivers often have different flow rates depending on the location, the more the number of rivers installed, the more accurate the flow rate can be ascertained.

  In addition, it is desirable to provide a protective work for protecting the water pressure measuring means and the hydrostatic pressure measuring means from obstacles such as falling objects around the water pressure measuring means and the hydrostatic pressure measuring means.

  The transmission means is arbitrary as long as it can transmit the data measured by the water pressure measurement means and the hydrostatic pressure measurement means to the arithmetic processing device, and may be wired or wireless.

  As long as the arithmetic processing unit can calculate the flowing water pressure from the difference between the water pressure and the hydrostatic pressure and can calculate the flow velocity from the flowing water pressure, the configuration is arbitrary.

  In calculating the flow velocity, when a plurality of water pressure measuring means and hydrostatic pressure measuring means are installed in the vertical direction at different depths, it is desirable to calculate the average flow velocity from the flow velocity at each depth.

  In addition, the arithmetic treatment device may be configured to calculate only the flow velocity. However, when the arithmetic processing device is configured to calculate the water level of the river from the hydrostatic pressure, a change in weather, etc. This makes it possible to accurately grasp the water level of a river that fluctuates in real time in real time.

  In addition, a storage device that stores the flow cross-sectional shape or flow cross-sectional area at an arbitrary water level of the river is provided, and the arithmetic processing unit reads and reads the flow cross-sectional shape or flow cross-sectional area corresponding to the calculated water level from the storage device. In the case where the flow rate is calculated using the flowing water cross-sectional shape or the flowing water cross-sectional area and the flow velocity, the flow rate of the river can be accurately grasped in real time.

  When calculating the flow rate, for example, calculate the flow cross-sectional area from the calculated water level and the cross-sectional shape of the flowing water corresponding to the water level, or if the flow cross-sectional area is stored, correspond to the calculated water level. It is conceivable to calculate the average flow velocity and calculate the flow rate from the product of the average flow velocity and the flowing water cross-sectional area while directly reading out the flowing water cross-sectional area.

  The storage device may be configured in any manner as long as the flowing water cross-sectional shape or the flowing water cross-sectional area at an arbitrary water level in the river is stored.

  The hydrostatic pressure measuring means is arbitrarily configured as long as it can measure the hydrostatic pressure, and the hydrostatic pressure measuring means is also configured as long as it can measure the hydrostatic pressure. However, the water pressure measuring means can be a soil pressure gauge and the hydrostatic pressure measuring means can be a pore water pressure gauge.

  Embodiments of a flow velocity measuring system according to the present invention will be described below with reference to the accompanying drawings. Note that components that are substantially the same as those of the prior art are assigned the same reference numerals, and descriptions thereof are omitted.

  FIG. 1 is a schematic view showing a flow velocity measuring system according to the present embodiment. As shown in the figure, the flow velocity measuring system 1 according to the present embodiment includes a soil pressure gauge 3 that is a water pressure measuring means attached to a pier 2 of a bridge 12 that is erected on the bottom of a river, and a gap that is a hydrostatic pressure measuring means. Water pressure gauge 4, wireless device 5 as transmission means, arithmetic processing device 8 and storage device 9 built in personal computer main body 7 installed in river management office 6 built in the vicinity of bridge 12, output means The liquid crystal monitor 10 is generally configured.

  A plurality of earth pressure gauges 3 are attached to the upstream circumferential surface of the pier 2 at different depths, and the pore water pressure gauge 4 is arranged on the upstream circumferential surface of the pier 2 so as to have the same depth as each earth pressure gauge 3. A plurality of pressure gauges 3 are attached so as to be adjacent to the pressure gauge 3.

  The earth pressure gauge 3 is configured so as to be able to measure the water pressure acting on the pressure receiving surface, that is, the combined water pressure of the hydrostatic pressure and the flowing water pressure, but may be appropriately selected from general-purpose products. In addition, when installing the earth pressure gauge 3, the earth pressure gauge 3 is arranged so that the pressure receiving surface of the earth pressure gauge 3 is orthogonal to the flow of the river so that the hydrostatic pressure and the flowing water pressure can be measured. Install it so that it faces.

  The pore water pressure gauge 4 is configured to measure the hydrostatic pressure, but may be appropriately selected from general-purpose products. In addition, when attaching the pore water pressure gauge 4, it attaches so that a receiving surface may face the non-upstream side as needed so that it may not receive to the influence of flowing water pressure.

  In addition, a protective work composed of a plurality of reinforcing bars bent in a U-shape is attached so as to surround the earth pressure gauge 3 and the pore water pressure gauge 4, and the earth pressure gauge 3 and the pore water pressure gauge 4 are connected to obstacles such as falling objects. Can be protected from.

  The wireless device 5 is installed in the vicinity of the center of the bridge 12, and the processing device 8 is built in the measurement data of the water pressure measured by the earth pressure gauge 3 and the measurement data of the hydrostatic pressure measured by the pore water pressure gauge 4. It can be transmitted to the personal computer body 7. Each earth pressure gauge 3 and pore water pressure gauge 4 are connected to the radio device 5 via a cable 11.

  The storage device 9 uses the flow cross-sectional area on the vertical plane including the position where the earth pressure gauge 3 and the pore water pressure gauge 4 are attached as the flow cross-sectional area at an arbitrary water level, in other words, the water flow using the water level on the vertical plane as a parameter. It is stored as a cross-sectional area.

That is, as shown in FIG. 2 (a), the storage device 9 has three vertical basins 21 and 22 at the center of the span of adjacent piers 2 and 2 (vertical lines indicated by solid lines in the figure). , 23, the above-described flow cross-sectional areas are stored as flow cross-sectional areas A ₁ , A ₂ , A ₃ for each basin. Note that the river cross-sectional area of the river with the water level as a parameter is measured in advance, and if the shape of the river bottom changes due to, for example, flooding, it is stored in the storage device 9 by performing measurement again as appropriate. It is desirable to keep the data consistent with the current situation.

  The storage device 9 can also store the measurement data transmitted from the wireless device 5 and the calculation result of the arithmetic processing device 8.

  The arithmetic processing unit 8 can calculate the flowing water pressure from the difference between the water pressure and the hydrostatic pressure, and can calculate the flow velocity from the flowing water pressure. Further, the arithmetic processing unit 8 calculates the water level of the river from the hydrostatic pressure, reads the flow cross-sectional area corresponding to the water level from the storage device 9, and calculates the flow rate using the read water cross-sectional area and the read flow velocity. It is configured to be able to.

  The liquid crystal monitor 10 can display the flow velocity, water level, and flow rate calculated by the arithmetic processing unit 8 in real time.

  In the flow velocity measuring system 1 according to the present embodiment, first, the water pressure is measured by the earth pressure gauge 3 attached to the upstream peripheral surface of the pier 2 erected on the river bottom, and the peripheral surface of the pier 2 is The hydrostatic pressure is measured with a pore water pressure gauge 4 attached so as to have the same depth as the earth pressure gauge 3.

  Next, the measurement data of the water pressure and the hydrostatic pressure are transmitted to the arithmetic processing unit 8 built in the personal computer body 7 by the wireless device 5.

  Next, the flow pressure, flow velocity, water level, and flow rate are calculated by the arithmetic processing unit 8 from the measurement data of the water pressure and the hydrostatic pressure transmitted from the wireless device 5 and the river flow cross-sectional area data stored in the storage device 9. .

  Specifically, as shown in FIG. 2 (b), underwater, the hydrostatic pressure acting in proportion to the water depth (broken line portion in the figure) and the flowing water pressure acting in proportion to the flow velocity (shaded line in the figure). Therefore, first, subtract the hydrostatic pressure measured by the pore pressure gauge 4 from the hydraulic pressure measured by the earth pressure gauge 3 to calculate the flowing water pressure. Calculate the flow rate.

Furthermore, since a plurality of earth pressure gauges 3 and pore water pressure gauges 4 are installed at different depths along the vertical direction of each pier 2, earth pressure gauges installed for each pier 2 as shown in FIG. 3 and average values of the flow velocities obtained from the measurement data of the pore water pressure gauge 4 are taken as average flow velocities v ₁ , v ₂ , v ₃ in the basins 21, 22, 23, respectively.

On the other hand, the water level of the river at the time of the measurement is calculated from the hydrostatic pressure, and the flow cross-sectional areas A ₁ , A ₂ , A ₃ of the basins 21, 22, 23 at the water level are read from the storage device 9.

Next, the flow rate Q of the river is calculated from the product of the average flow velocity v _i and the flowing water cross-sectional area A _i as follows.
Q = Σv _i · A _i

  Next, the calculated flow velocity, water level and flow rate are displayed on the liquid crystal monitor 10.

  As described above, according to the flow velocity measurement system 1 according to the present embodiment, the earth pressure gauge 3 and the pore water pressure gauge 4 are attached to the bridge pier 2 to measure the water pressure and the hydrostatic pressure, and the measurement data is transmitted to perform arithmetic processing. Since the flow velocity is calculated by the device 8, automatic measurement of water pressure and hydrostatic pressure is possible, and the flow velocity of the river can be accurately grasped in real time even during a flood. Incidentally, it goes without saying that flood information can be shared or disclosed in real time using the Internet.

  Moreover, according to the flow velocity measuring system 1 according to the present embodiment, the arithmetic processing unit 8 is configured to calculate the river level from the hydrostatic pressure, so that the river level that fluctuates due to changes in weather and the like can be accurately determined in real time. It becomes possible to grasp.

  Moreover, according to the flow velocity measurement system 1 according to the present embodiment, the storage device 9 that stores the flowing water cross-sectional area at an arbitrary water level of the river is provided, and the flowing water cross-sectional area corresponding to the measured water level is read from the storage device 9. Since the arithmetic processing unit 8 is configured to calculate the flow rate using the flowing water cross-sectional area and the flow velocity read together, the river flow rate can be accurately grasped in real time.

  In the present embodiment, the arithmetic processing device 8 is configured to calculate the water level and the flow rate in addition to the flow velocity, but the arithmetic treatment device is not necessarily configured in this way, and the above-described calculation of the water level and the flow rate is omitted. The flow rate alone may be calculated, or the flow rate may be omitted and the flow rate and water level may be calculated.

  In the present embodiment, the storage device 9 is configured to store the flowing water cross-sectional area at an arbitrary water level. Instead, the storage device is configured to store the flowing water cross-sectional shape at an arbitrary water level. It doesn't matter. In such a case, when calculating the flow rate using the arithmetic processing unit, first, the flow cross-sectional shape corresponding to the calculated water level is read from the storage device, and the flow cross-sectional area is calculated from the flow cross-sectional shape and the water level. Then, the flow rate is calculated from the flowing water cross-sectional area and the flow velocity.

  Further, in the present embodiment, a plurality of earth pressure gauges 3 and pore water pressure gauges 4 are respectively attached. However, for example, when the water level is low, only one may be used.

  In the present embodiment, the water pressure measuring means is the earth pressure gauge 3 and the hydrostatic pressure measuring means is the pore water pressure gauge 4. However, what is the water pressure measuring means as long as the water pressure can be measured? For example, a hydrometer may be used, and any hydrostatic pressure measuring means may be used as long as the hydrostatic pressure can be measured.

  In the present embodiment, the wireless device 5 is used to transmit the measurement data to the arithmetic processing unit 8. However, the wireless device 5 is not necessarily used. For example, the wireless device 5 is omitted and the arithmetic processing is performed. The device may be connected with a cable, or the transmission means may be built in the water pressure measurement means and the hydrostatic pressure measurement means, and may be directly transmitted without using a cable.

  In the present embodiment, the liquid crystal monitor 10 is used as the output means. Instead, for example, a display or a printer may be used as the output means.

Moreover, in this embodiment, the value of each flow velocity obtained from the measurement data of the earth pressure gauge 3 and the pore water pressure gauge 4 attached to each pier 2 is averaged, and these values are respectively obtained in the basins 21, 22 and 23. Although the average flow velocities v ₁ , v ₂ , and v ₃ are used, the flow velocities obtained from the measured data of the earth pressure gauge 3 and the pore water pressure gauge 4 are affected by eddy currents behind the pier 2 and so on. An error may occur with the flow velocity. In such a case, each flow rate obtained from the measurement data by performing analysis or experiment may be corrected as appropriate.

  Similarly, when the number of earth pressure gauges 3 and pore water pressure gauges 4 attached to each pier 2 is small, the flow rate obtained from the measurement data and thus the river flow rate may cause an error from the actual flow rate. Conceivable.

  In such a case, the correlation between the number of measurement points or measurement points and the actual flow velocity or flow rate is obtained in advance by analysis or experiment as a correction curve, and by fitting the number of measurement points or measurement points to the correction curve, What is necessary is just to correct | amend a flow velocity or a flow volume suitably.

Schematic which showed the flow velocity measurement system which concerns on this embodiment. Sectional drawing which showed the effect | action of the flow velocity measuring system which concerns on this embodiment.

Explanation of symbols

1 Flow velocity measurement system 2 Bridge pier 3 Earth pressure gauge (water pressure measurement means)
4 pore water pressure gauge (hydrostatic pressure measuring means)
5 Radio (Transmission means)
8 Arithmetic processing device 9 Storage device

Claims (4)

A water pressure measuring means attached to the upstream peripheral surface of the bridge pier standing on the river bottom, and measuring the water pressure at the mounting position, and the peripheral surface of the bridge pier and having the same depth as the water pressure measuring means. The hydrostatic pressure measuring means for measuring the hydrostatic pressure attached and at the mounting position, the transmitting means for transmitting the hydrostatic pressure and the hydrostatic pressure measurement data, and the flowing water pressure from the difference between the hydrostatic pressure and the hydrostatic pressure. A flow velocity measurement system comprising: an arithmetic processing unit for calculating and calculating a flow velocity from the flowing water pressure. The flow velocity measurement system according to claim 1, wherein the arithmetic processing unit is configured to calculate a water level of the river from the hydrostatic pressure. A storage device that stores a flow cross-sectional shape or a flow cross-sectional area at an arbitrary water level of the river is provided, and the arithmetic processing unit is configured to store the flow cross-sectional shape or the flow cross-sectional area corresponding to the calculated water level from the storage device. The flow velocity measurement system according to claim 2, wherein the flow rate is calculated using the flowing water cross-sectional shape or flowing water cross-sectional area and the flow velocity read out and read out. The flow velocity measuring system according to any one of claims 1 to 3, wherein the water pressure measuring means is a soil pressure gauge, and the hydrostatic pressure measuring means is a pore water pressure gauge.

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