JP6088862B2 - Open channel displacement meter - Google Patents

Description

  The present invention relates to an open channel displacement meter, and more specifically to an open channel displacement meter technique that enables accurate vertical displacement measurement in a short time.

  There is an open channel displacement meter as a device for measuring a vertical displacement in a structure. An open channel type displacement meter has a basic structure with a so-called open channel that is open to the atmosphere, and performs displacement measurement at a series of measurement points provided at predetermined intervals along the open channel. Each measurement point is provided with a water tank with a floating float and an eddy current sensor for detecting the amount of vertical movement of the float. The aquarium is connected to the structure and shows the movement of the subsidence and uplift as the structure subsidence and uplift. For example, when a tank of a certain point sinks due to the subsidence of a structure, the vertical distance between the floating top of the surface where the water level is constant regardless of the tank subsidence and the eddy current sensor that sinks with the tank However, it changes from the state before subsidence. The relative displacement amount between the measurement points can be detected from the change amount.

  Such an open-channel displacement meter has characteristics that provide stable measurement results against environmental changes such as temperature and humidity, and is often applied to situations where long-term stable displacement measurement is required. I came. As a prior art of an open channel displacement meter, for example, a liquid path along a reference linear body stretched between fixed points is formed between the fixed points, and a reference line is stored in the liquid stored in the liquid path. By holding the rod-like body, the apparent weight of the reference linear body is reduced to suppress loosening of its own weight, and the fluctuation of the reference linear body, temperature fluctuation, temperature fluctuation due to the mechanical and thermal damper characteristics of the liquid A displacement measurement technique (see Patent Document 1) that suppresses the expansion and contraction associated with is proposed.

Japanese Patent No. 3780377

  However, since the conventional open channel displacement meter is difficult to measure accurately until the fluctuation of the water surface in the aquarium according to the behavior of the structure converges, the displacement measurement of the structure when applying the underpinning method, etc. This is not suitable for situations where measurement results need to be obtained in a short time. On the other hand, when measuring equipment such as a dial gauge displacement meter is installed in order to perform such measurement in a short time, a measurement mechanism different from the existing open channel displacement meter is added. And led to an increase in labor.

  Then, this invention aims at provision of the technique of the open channel type displacement meter which enables the accurate vertical displacement measurement in a short time.

  The open channel type displacement meter of the present invention that solves the above-mentioned problems connects aquariums arranged at a plurality of measurement points with water channels, and the relative relationship between the aquarium and the water surface position before and after occurrence of vertical displacement at the measurement points. An open channel displacement meter with a free water surface that detects the vertical displacement generated at a measurement point based on the amount of change, and is formed by connecting water tanks of two or more measurement points in a closed circuit form by a water channel It is characterized by that.

  According to this, when a vertical displacement occurs in the structure to be measured, the water surface shakes at the water tank installed near the location where the vertical displacement occurs. Propagates to two or more water channels toward one or more other water tanks connected to the point water tank. Therefore, as compared with the conventional open-channel displacement meter composed of a row of unclosed water channels and measurement point water tanks, there are more propagation paths for water surface fluctuations. The more undulating volume of water propagates to the two or more water channels 20 that are more than conventional, so that the water can be leveled more quickly and the oscillation can be quickly converged. In other words, according to the present invention, the water surface fluctuation in the open channel displacement meter due to the vertical displacement generated in the structure is quickly converged, and the accurate vertical displacement in the open channel displacement meter is settled in a short time on the calm water surface. Displacement measurement is possible. In addition, in the case of an open channel displacement meter in which three or more measuring tanks are connected in a closed circuit by a water channel, in addition to the effect of increasing the propagation path described above, the fluctuation of the water surface generated in one water tank is Propagation through the water channels extending from both sides of the water tank toward other water tanks increases the propagation area per hour of the water surface fluctuation, and the convergence of the water surface fluctuation is further accelerated.

  In addition, the open channel displacement meter of the present invention connects water tanks arranged at a plurality of measurement points with water channels, and the relative change between the water tank and the water surface position before and after the occurrence of vertical displacement at the measurement points. Based on this, it is an open channel type displacement meter having a free water surface that detects vertical displacement generated at a measuring point, and includes a plurality of units in which water tanks of two or more measuring points are connected in a closed circuit shape by a water channel. The unit is provided with a structure in which the units are connected by sharing a water tank or water channel of at least one measuring point of each unit.

  According to this, when a vertical displacement occurs in the structure to be measured, water surface fluctuation occurs in the water tank at the measurement point near the place where the vertical displacement occurs. Propagating to two or more connected aquariums in a unit containing two or more connected stations, and also to other units sharing the measuring tank with the unit. Therefore, the swing can be converged more rapidly as compared with a conventional open channel type displacement meter constituted by a single row of closed water channels and a measuring point water tank. In other words, according to the present invention, the water surface fluctuation in the open channel displacement meter due to the vertical displacement generated in the structure is quickly converged, and the accurate vertical displacement in the open channel displacement meter is settled in a short time on the calm water surface. Displacement measurement is possible.

  ADVANTAGE OF THE INVENTION According to this invention, the exact vertical displacement measurement in a short time in an open channel type displacement meter is attained.

It is a top view which shows the structural example 1 of the open channel type displacement meter in this embodiment. It is a top view which shows the structural example 2 of the open channel type displacement meter in this embodiment. It is a sectional side view which shows the structural example 1 of the open channel type displacement meter in this embodiment. It is a sectional side view which shows the structural example 2 of the open channel type displacement meter in this embodiment. It is a top view which shows the structural example 3 of the open channel type displacement meter in this embodiment. It is a top view which shows the structural example 4 of the open channel type displacement meter in this embodiment. It is a sectional side view which shows the structural example 3 of the open channel type displacement meter in this embodiment. It is a sectional side view which shows the structural example 4 of the open channel type displacement meter in this embodiment. It is a top view which shows the structural example 5 of the open channel type displacement meter in this embodiment. It is a sectional side view which shows the structural example 5 of the open channel type displacement meter in this embodiment. It is a top view which shows the structural example 6 of the open channel type displacement meter in this embodiment. It is a sectional side view which shows the structural example 6 of the open channel type displacement meter in this embodiment. It is a perspective view which shows the structural example of the water tank in the open channel type displacement meter of this embodiment. It is a front view which shows the structural example of the water tank in the open channel type displacement meter of this embodiment. It is a side view which shows the structural example of the water tank in the open channel type displacement meter of this embodiment. It is a sectional side view which shows the structural example (normal time) of the water tank in this embodiment. It is a sectional side view which shows the structural example (at the time of displacement) of the water tank in this embodiment. It is a figure which shows the example of the water surface protrusion in the open channel type displacement meter in this embodiment. It is a figure which shows the concept of the water flow cross-sectional area in the open channel type displacement meter in this embodiment. It is a figure which shows the example of propagation of the water surface fluctuation | variation in the conventional open channel type displacement meter. It is a figure which shows the example of propagation of the water surface fluctuation | variation in the conventional open channel type displacement meter. It is a figure which shows the example of propagation of the water surface fluctuation | variation in the open channel type displacement meter of this embodiment. It is a figure which shows the example of propagation of the water surface fluctuation | variation in the open channel type displacement meter of this embodiment. It is a figure which shows the stepwise propagation condition 1 of the water surface fluctuation | variation in the other open channel type displacement meter of this embodiment. It is a figure which shows the stepwise propagation condition 2 of the water surface fluctuation | variation in the other open channel type displacement meter of this embodiment. It is a figure which shows the stepwise propagation condition 3 of the water surface fluctuation | variation in the other open channel type displacement meter of this embodiment. It is a figure which shows the stepwise propagation condition 4 of the water surface fluctuation | variation in the other open channel type displacement meter of this embodiment.

  Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a plan view showing a structural example 1 of an open channel displacement meter 100 in the present embodiment, and FIG. 3 is a side sectional view showing a structural example 1 of the open channel displacement meter 100 in the present embodiment. The open channel type displacement meter 100 according to the present embodiment is a displacement meter that can perform stable displacement measurement over a long period of time as usual and can also perform accurate vertical displacement measurement in a short time. An open channel displacement meter 100 shown in FIGS. 1 and 3 has a structure in which water tanks 11 of three measuring points 10 provided at predetermined intervals are connected by a water channel 20 in a triangular closed circuit shape. Moreover, the water tank 11 of any one of the measurement points 10 is fixed to a solid foundation 2 or the like that does not cause vertical displacement, and serves as a reference point 10B when calculating the relative displacement amount between the measurement points. As shown in the structural examples of FIGS. 2 and 4, a plurality of units 50 formed by connecting the water tanks 11 of the three measuring points 10 in a triangular closed circuit shape by the water channel 20 are provided. It is good also as providing the structure which shared and connected the water tank 11 thru | or the water channel 20 of at least 1 measuring point 10 of these. In the example shown in FIGS. 2 and 4, the water tanks 11 of the two measuring points 10C and 10B and the water channel 20A connecting them are shared by each unit.

  In addition, unlike the configuration of the open channel displacement meter 100 of FIGS. 1 and 3, the open channel displacement meter 100 having a configuration in which the water tanks 11 of the two measuring points 10 are connected in a closed circuit shape by the water channel 20 may be adopted. I can do it. FIG. 5 is a plan view showing Structural Example 3 of the open channel displacement meter in the present embodiment, and FIG. 6 is a plan view showing Structural Example 4 of the open channel displacement meter in the present embodiment.

  5 and FIG. 7 has a structure in which a water tank 11 of two measuring points 10 provided at a predetermined interval is connected in a looped closed circuit form with a water channel 20. Moreover, the water tank 11 of any one of the measurement points 10 is fixed to a solid foundation 2 or the like that does not cause vertical displacement, and serves as a reference point 10B when calculating the relative displacement amount between the measurement points. Moreover, as shown in the structural example of FIG. 6, FIG. 8, it has two or more units 50 which connect the water tank 11 of the two measuring points 10 with the water channel 20 in the loop-shaped closed circuit form, and unit 50 is each unit. A structure in which 50 water tanks 11 of at least one measuring point 10 are shared and connected may be provided. In the example shown in FIGS. 6 and 8, the unit 50A including the measurement point 10B and the unit 50B including the measurement point 10E share the water tank 10D.

  9 and 10 includes a plurality of units 50 formed by connecting the water tanks 11 of the two measuring points 10 in a looped closed circuit form with the water channels 20, and the units 50 are connected to each other. It is good also as providing the structure which shared and connected 20 A of water channels which connect between units. In the example shown in FIGS. 9 and 10, the water channel 20A is shared by the unit 50A including the measurement points 10B and 10F and the unit 50B including the measurement points 10E and 10D.

  Furthermore, as shown in FIG. 11 and FIG. 12, a plurality of rectangular units 50 formed by connecting the water tanks 11 of the four measuring points 10 in a closed circuit shape with the water channels 20 are provided, and the units 50 are at least of each unit 50. It is good also as providing the structure which shared and connected the water tank 11 of the one measuring point 10. FIG. In the example shown in FIG. 11 and FIG. 12, in the unit 50X of the unit 50X on the end side in the open channel displacement meter 100, the aquarium 11 of the measuring points 10E to 10G other than the measuring point 10D of the corner portion, and the measuring point Water channels 20D and 20E other than water channels 20B and 20C connected to 10D are shared with surrounding units. Further, in a unit other than the end of the open channel displacement meter 100, for example, the unit 50Y shown in FIG. 11, the water tank 11 of all the measuring points 10S to 10V and the water channel 20F corresponding to the outer peripheral portion of the open channel displacement meter 100. The other water channels 20G, 20H, and 20I are shared with surrounding units.

  FIG. 13 is a perspective view showing a structural example of the water tank 11 in the open channel displacement meter 100 of the present embodiment, and FIG. 14 is a front view showing a structural example of the water tank 11 in the open channel displacement meter 100 of the present embodiment. FIG. 15 is a side view showing an example of the structure of the water tank 11 in the open channel displacement meter 100 of the present embodiment. FIG. 16 is a side sectional view showing a structural example (normal time) of the water tank in this embodiment, and FIG. 17 is a side sectional view showing a structural example (displacement) of the water tank in this embodiment.

  As shown in FIG. 13, at the measuring point 10, a box-shaped water tank 11 is erected with the base portion 17 fixed to the structure as a bottom portion. In this water tank 11, a plurality of water channels 20 are connected, and the inner space of each water channel 20 is in communication with the inner space of the water tank 11.

  Further, as shown in FIGS. 14 and 15, water 12 is stored in the inner spaces of the water tank 11 and the water channel 20 of the measuring point 10, and the float 14 is floated on the water surface 13. An eddy current sensor 16 for detecting the vertical movement amount of the float 14 is installed at the top end 15 in the water tank at a separation distance bb (see FIG. 16). In addition, the water tank 11 is integrally connected to the structure 1 via the above-described base portion 17, and similarly, along with the vertical displacement aa (see FIG. 17) such as the sinking or rising of the structure 1, Show movement.

  For example, it is assumed that the structure 1 sinks by a distance aa (see FIG. 17), and the water tank 11 at a certain measurement point 10 also sinks along with the sinking. On the other hand, the water 12 stored in the water tank 11 of each measuring point 10 can behave integrally between the water tanks 11 via the water channel 20, so that a certain time has passed even if the above-mentioned settlement occurs and the water surface fluctuates. Then, the water 12 in each water tank 11 maintains a constant water level regardless of the water tank subsidence.

  Accordingly, the vertical distance cc between the buoyant ceiling 14A on the water surface 13 where the water level is constant between the water tanks 11 and the eddy current sensor 16 that sinks together with the water tank 11 of the measuring point 10 where the sinking has occurred (see FIG. 17). Changes in the direction of contraction from the separation distance bb before sinking. The relative displacement amount between the measurement points can be detected from the change amount. In addition, what is necessary is just to employ | adopt an existing technique about the calculation method of this relative displacement amount.

  When a vertical displacement such as uplift or subsidence occurs in the structure 1, the water surface 13 oscillates in the water tank 11 of the measuring point 10 located near the location where the vertical displacement occurs. In particular, in the situation where a sudden vertical displacement occurs, such as when measuring the displacement of the structure 1 to which the underpinning method is applied, the above-described water surface fluctuation tends to increase. However, in the open channel type displacement meter 100 of the present embodiment, the water in a volume that undulates from the normal water surface due to the water surface fluctuation generated in the water tank 11 at any one of the measurement points 10 is the water tank 11 at the corresponding measurement point 10. It is leveled quickly by propagating to two or more water channels 20 toward the other two or more water tanks 11 connected to the water tank 11, and as before, a single row of water channels that are not closed and the water tank of the station Compared with the open channel type displacement meter configured as described above, the swing can be quickly converged.

  Further, if a structure in which a plurality of units 50 are combined as described above, when vertical displacement occurs in the structure 1 to be measured, the water surface swings in the water tank 11 of the measuring point 10 near the place where the vertical displacement has occurred. However, the water surface fluctuation propagates to the two or more water channels 20 toward the one or more other water tanks 11 of the station 10 in the unit 50 including the water tank 11 of the corresponding station 10. Further, since the propagation is made in the same manner to the other units sharing the tank 11 of the station 50 with the unit 50, as in the prior art, an open channel type displacement constituted by one row of unclosed water channels and the tank of the station is provided. Compared with the meter, the oscillation can be converged more rapidly.

Here, regarding the conventional open channel displacement meter constituted by a single row of unclosed water channels and a measuring point water tank, and the open channel displacement meter 100 of the present embodiment, the propagation condition of the water surface fluctuation is respectively simulated. An example is shown. First, the following two cases were adopted as cases for comparison.
Case 1 (conventional type): The measuring point interval is 10.0 m. The total length of the canal 20 is 80m.
Case 2 (this embodiment): The measuring point interval is 10.0 m. The total length of the canal 20 is 80m. A rectangular unit 50 in which four measurement points 10 are connected in a closed circuit shape by a water channel 20 is arranged in an eight-row grid pattern.

  Also, the assumed vertical displacement condition is that a certain measurement point 10 is raised by 0.5 mm, and the elevation of 0.5 mm at that measurement point 10 is the apex, and the water tank 11 of the corresponding measurement point 10 is connected. The water channel 20 is inclined and raised in a triangular shape (see the upper part of FIG. 18). On the other hand, the other measuring points 10 and the water channel 20 are not displaced. Assuming a vertical displacement under such conditions, the water surface fluctuation of the water 12 in the water tank 11 that has risen with the rising of the station 10 is transferred to a plurality of other stations 10 via the plurality of other water channels 20. It is assumed that the water surface 13 is flattened as time passes.

Here, the propagation speed of the water surface fluctuation of the water surface 13 in the water tank 11 is calculated. The propagation velocity V of the water surface fluctuation, that is, the water level change is expressed by the following equation:

It is represented by Here, g: gravitational acceleration = 9.8 m / s ² , h: hydraulic depth = water cross-sectional area A ÷ water surface width B. If the pipe diameter of the water channel 20 is 78 mm and the water depth in the pipe of the water channel 20 is ½ of the pipe diameter,

  When the propagation velocity V is 0.55 m / s, the time required for the water 12 (water surface fluctuation) to travel by 10.0 m which is the unit length of the water channel 20 is 10.0 m ÷ 0.55 m / s. ≒ 18 seconds.

Here, the volume C of the water 12 generated by the bulging of the measuring point 10A can be approximated to a rectangular parallelepiped because the distance between the measuring points is sufficiently larger than the bulging amount (see the lower part of FIG. 18). Therefore, the volume C is C = (length of water surface fluctuation) × (water surface width B) × (water level at the measuring point 10A). In this case, “(length of water surface fluctuation) × (water surface width B)” is defined as a propagation area A. Since the volume C does not change with the passage of time, the water level of the measuring point 10A at time t _n and t _{n + 1} is h _n , h _{n + 1} , and the propagation area is A _n and A _{n + 1} , respectively.
・ Volume C = h _n × A _n = h _{n + 1} × A _{n + 1}
・ Water level h _{n + 1 of the} measuring point 10A = (A _n / A _{n + 1} ) × h _n
It becomes.

_Therefore, the _{A n /} A n _{+ 1} and the propagation area ratio, if determined the water level _{h n + 1} of the measuring point 10A at time _{t n + 1,} be multiplied propagation area ratio to the water level _{h n} of measuring points 10A at time _{t n} Good.

FIGS. 20 and 21 show the results when the above conditions are applied to the above-described case 1, that is, the conventional open channel displacement meter. In the case of the example in FIG. 20, the station where the bulge occurred is the station 10 </ b> A. Therefore, at the time t = 0 when the bulge occurs, the water channel 20 directly connected to the measurement point 10A also has an inclined ridge with the bulge at the measurement point 10A as the apex. Since the unit length of the water channel 20 is 10.0 m, the range in which the bulge is generated at the time t = 0 is 10.0 m in each direction around the measurement point 10A, that is, a range of 20 m in total. Further, the propagation area at this point is 20 m in total length of the water channel 20 within the above-mentioned range × the water surface width of the water channel 20 is 0.078 m = 1.56 m ² .

  In order for the water surface fluctuation of the water 12 to propagate by the unit length 10.0 m of the water channel 20, it takes about 18 seconds as described above. Therefore, after 18 seconds from the time t = 0 when the uplift occurred, the water surface fluctuation of the water 12 raised at the measuring point 10A is 20 m in each direction centering on the measuring point 10A, that is, a total range of 40 m.

In this case, as shown in the table of FIG. 21, the propagation area of the water surface fluctuation is the total length of the water channel 20 within the above-mentioned range 40 m × the water surface width 0.078 m = 3.12 m ² of the water channel 20. Since the propagation area at the time t = 0 is 1.56 m ² as described above, the propagation area ratio at the time t = 18 seconds is 1.56 m ² /3.12 m ² = 0. 5 Therefore, the water level at the measurement point 10A at the time t = 18 seconds is calculated as 0.25 mm by multiplying the propagation area ratio 0.5 by the water level 0.5mm at the measurement point 10A at the time t = 0. it can.

Then, after 18 seconds have passed, that is, 36 seconds after the time t = 0 when the uplift occurred, the water surface fluctuation of the water 12 raised at the measuring point 10A is 30.0 m in each direction around the measuring point 10A. That is, the total range is 60 m. In this case, as shown in the table of FIG. 21, the propagation area of the water surface fluctuation is the total length of the water channel 20 within the above-mentioned range 60 m × the water surface width 0.078 = 4.68 m ² of the water channel 20. In this case, the ratio of the propagation area between the times can be calculated as 3.12 / 4.68 = 0.6667 as in the case of the above-described time t = 18 seconds.

  Further, the water level at the measuring point 10A at the time t = 36 seconds is the propagation area ratio 0.6667 at the time t = 36 seconds, and the water level at the measuring point 10A at the time t = 18 seconds is 0. By multiplying by 25 mm, it can be calculated as 0.17 mm. Similarly, the water level at the measuring point 10A at time t = 54 seconds is 0.13 mm.

  Similarly, FIGS. 23 to 27 show results when the above-described conditions are applied to the case 2 described above, that is, the open channel displacement meter 100 (see FIG. 22) of the present embodiment. Even in the case of the example in FIG. 22, a measurement point where a bulge has occurred is defined as a measurement point 10 </ b> A. Further, the range in which the water surface fluctuation is propagated every 18 seconds from the time t = 0 when the bulge occurs is the same as in the case 1 described above. Further, from the open channel displacement meter 100 shown in FIG. 22, only the ranges of the measurement point 10, the water channel 20, and the auxiliary water channel 30 in which the water surface fluctuation has propagated are extracted at each time after the above-described bulge occurs. These are shown in FIG. 24 (t = 0 second) to FIG. 27 (t = 54 seconds), respectively.

First, as shown in FIG. 24, the range where the bulge is generated at the time t = 0 is 10.0 m in each direction around the measurement point 10A, that is, a total range of 40 m. In addition, the propagation area at this point is 40 m in total length of the water channel 20 within the above-mentioned range × the water surface width of the water channel 20 is 0.078 m = 3.12 m ² .

Further, at time t = 18 seconds, as shown in FIG. 25, the water surface fluctuation has reached a range of 20 m in each direction around the measuring point 10A, that is, a total range of 40 m. Therefore, when the number of sections of the water channel 20 and the auxiliary water channel 30 in this range is counted, it becomes 16 sections. As shown in the table of FIG. 23, the propagation area of the water surface fluctuation corresponds to the length in which the water channel 20 and the auxiliary water channel 30 each having a unit length of 10.0 m are a total of 16 sections, that is, 16 (Section) × 10.0 m × Water surface width 0.078 m = 12.48 m ² . Propagation area ratio at this point, the propagation area 3.12M ² at time t = 0 of the above is divided by the propagation area 12.48M ² at time t = 18, 0.25. Further, the water level at the measurement point 10A at this time can be calculated as 0.12 mm by multiplying the propagation area ratio 0.25 by the water level 0.5mm of the measurement point 10A at time t = 0.

Then, after 18 seconds have passed, that is, 36 seconds after the time t = 0 when the uplift occurred, the water surface fluctuation of the water 12 raised at the measuring point 10A is 30.0 m in each direction around the measuring point 10A. That is, the total range is 60 m. In this case, if the number of sections of the water channel 20 and the auxiliary water channel 30 in this range is counted, it becomes 36 sections. Therefore, as shown in the table of FIG. 22, the propagation area of the water surface fluctuation corresponds to the length in which the water channel 20 and the auxiliary water channel 30 each having a unit length of 10.0 m are a total of 36 sections, that is, 36 (section) × 10.0 m × water surface width 0.078 m = 28.08 m ² . In this case, the ratio of the propagation area between times can be calculated as 12.48 / 28.08 = 0.444 as in the case of the above-described time t = 18 seconds.

  The water level at the measuring point 10A at the time t = 36 seconds is equal to the propagation area ratio 0.444 at the time t = 36 seconds, and the water level at the measuring point 10A at the time t = 18 seconds is 0. It can be calculated as 0.06 mm by multiplying by 12 mm. Similarly, the water level at the measuring point 10A at time t = 54 seconds is 0.03 mm. The water level at the measuring point 10A obtained for Case 1 (conventional type) rose 0.17 mm at time t = 36 seconds and 0.13 mm at time t = 54 seconds. It can be seen that the water level decreases, that is, the speed at which the water surface fluctuation converges is faster in the open channel displacement meter 100 of the present embodiment. That is, as long as the propagation velocity V is constant, the convergence of the water surface fluctuation caused by the uplift at the measurement point 10A becomes faster as the propagation area becomes larger.

  As described above, according to the present embodiment, the water surface fluctuation in the open channel displacement meter due to the vertical displacement generated in the structure is quickly converged, and the settled water surface can be accurately obtained in a short time in the open channel displacement meter. Vertical displacement measurement is possible.

  Although the embodiment of the present invention has been specifically described based on the embodiment, the present invention is not limited to this, and various modifications can be made without departing from the scope of the invention.

DESCRIPTION OF SYMBOLS 1 Structure 10 Measuring point 11 Water tank 12 Water 13 Water surface 14 Float 15 Water tank top 16 Eddy current sensor 17 Base part 20 Water channel 50 Unit 100 Open channel displacement meter

Claims (2)

  Aquariums located at multiple stations are connected by a water channel, and the vertical displacement generated at the station is detected based on the relative change between the tank and the water surface position before and after the occurrence of vertical displacement at the station. An open channel displacement meter having an open channel having a free water surface, wherein two or more measuring points are connected in a closed circuit by a channel.   Aquariums located at multiple stations are connected by a water channel, and the vertical displacement generated at the station is detected based on the relative change between the tank and the water surface position before and after the occurrence of vertical displacement at the station. An open channel type displacement meter comprising a plurality of units formed by connecting water tanks of two or more measuring points in a closed circuit form by water channels, and each unit has a water tank or water channel of at least one measuring point of each unit. An open channel displacement meter characterized by having a shared and tied structure.