JP2022030928A - Measuring device and measuring method - Google Patents

Abstract

To provide a measurement apparatus and a measurement method which can perform highly accurate measurement over a medium and long term.SOLUTION: A measurement apparatus 1 for measuring a displacement amount in a vertical direction of a structure as a change amount of a height of a liquid level of liquid comprises: a detection unit 10 which is installed at a measurement point P and stores first liquid and second liquid having different specific gravity; a connection unit 30 which extends from the detection unit 10 and has a first tubular member storing the first liquid and a second tubular member storing the second liquid; and a display unit 20 which has reading means that can read a position of the liquid level of the second liquid. The detection unit 10 has a coil part around which at least any of the first tubular member and the second tubular member is wound in a coil shape. A protective material is arranged so as to be in close-contact with the periphery of the first tubular member and the second tubular member.SELECTED DRAWING: Figure 1

Description

The present invention relates to a measuring device and a measuring method.

In the ground with poor geology, the invert part may rise because the external pressure exceeding the value assumed in the design may act not only on the upper part of the tunnel but also on the bottom part (invert part) of the tunnel.

If the uplift of the invert part continues, it is necessary to take measures according to the degree of the uplift phenomenon. In addition, since the placement of the lining concrete in the invert part is conditional on the convergence of the tunnel deformation, it is necessary to confirm by displacement measurement, and the displacement measurement in the invert part is important. For example, in the "Mountain Tunnel Design and Construction Standard" issued by the "Railway Construction and Transportation Facility Development Support Organization", the lining concrete of the invert part should be placed after confirming the convergence of the internal displacement. Is stipulated as the basis.

In connection with this, a measuring device has been developed that measures the amount of vertical displacement of a structure as the amount of change in the height of the liquid level (see Patent Document 1). The measuring device described in Patent Document 1 is installed at a measuring point and accommodates a first liquid and a second liquid having different specific densities, and a detection unit extending from the detection unit and accommodating the first liquid. It includes a connecting portion having a first tubular member and a second tubular member for accommodating the second liquid, and a display portion having a reading means capable of reading the position of the liquid surface of the second liquid.

Japanese Unexamined Patent Publication No. 2020-003287

As described above, in order to confirm the convergence of the tunnel deformation (inner air displacement), it is necessary to perform measurement over a medium- to long-term (for example, about several months). However, when the measuring device described in Patent Document 1 is used for a medium to long term, it is affected by the environment of the installation site. For example, in a dry environment, the liquid inside permeates the outside of the tubular member (in the atmosphere). It was found that the liquid level may unintentionally fluctuate due to the permeation of moisture on the outside (atmosphere) of the tubular member in a high humidity environment.

From such a viewpoint, the present invention provides a measuring device and a measuring method capable of highly accurate measurement over a medium to long term.

The measuring device according to the present invention is a measuring device that measures the amount of vertical displacement of a structure as the amount of change in the height of the liquid level.
This measuring device is installed at a measurement point and has a detection unit that accommodates a first liquid and a second liquid having different specific densities, a first tubular member that extends from the detection unit and accommodates the first liquid, and the said. It includes a connecting portion having a second tubular member for accommodating the second liquid, and a display portion having a reading means capable of reading the position of the liquid surface of the second liquid.
The detection unit has a coil portion in which at least one of the first tubular member and the second tubular member is wound in a coil shape, and a protective material is provided around the first tubular member and the second tubular member. They are placed in close contact with each other.

In the measuring device according to the present invention, since the protective material is closely arranged around the first tubular member and the second tubular member, the influence of the installation environment is affected inside the first tubular member and the second tubular member. And difficult. That is, it becomes difficult for a substance to flow into the first tubular member or the second tubular member from the outside or the working medium (heavy liquid, light liquid) to flow out to the outside, and eventually the volume of the working medium increases or decreases (that is, the liquid level). (The position of) fluctuates) can be suppressed. As a result, highly accurate measurement is possible over the medium to long term.

When the protective material is a protective liquid that exhibits a liquid, the detection unit includes a case portion having watertightness, the coil portion and the protective liquid are sealed in the case portion, and the connecting portion is watertight. It is preferable that a protective tube having a property is provided, and the first tubular member, the second tubular member, and the protective liquid are enclosed in the protective tube.

The protective liquid is preferably a liquid containing the same component as that of the first liquid and the second liquid, whichever has a lighter specific gravity.

By doing so, it is possible to suppress fluctuations in the liquid level due to the influence of osmotic pressure.

A first valve is installed at the tip of the first tubular member, and the tip side of the second tubular member may be branched into two, a first branch pipe and a second branch pipe. A second valve is installed in the first branch pipe, and a discharge nozzle for discharging the surplus second liquid via the third valve is installed in the second branch pipe. There is.

By doing so, the position of the liquid level can be easily adjusted, so that the displacement amount can be measured accurately and quickly.

Further, the measuring method according to the present invention is a measuring method for measuring the amount of vertical displacement of a structure as the amount of change in the height of the liquid level.
This measuring method includes a preparatory step for preparing the measuring device described above, an installation step for installing the measuring device in a structure to be measured, an adjusting step for adjusting the measuring device to an initial state, and the measuring device. It has a measurement process for measuring the amount of displacement using the product. Further, the adjustment step includes a first step, a second step, and a third step.
In the first step, the first valve and the third valve are opened from the state where the first valve, the second valve and the third valve are closed, and the liquid level of the first liquid is lowered. At the same time, the surplus amount of the second liquid is discharged from the discharge nozzle.
In the second step, the first valve is closed and the second valve is opened from the state of the first step to lower the liquid level of the second liquid and to remove the surplus second liquid. Further discharge from the discharge nozzle.
In the third step, the first valve is opened and the third valve is closed from the state of the second step.

In the measurement method according to the present invention, since the protective material is closely arranged around the first tubular member and the second tubular member, the influence of the installation environment is affected inside the first tubular member and the second tubular member. And difficult. That is, it becomes difficult for a substance to flow into the first tubular member or the second tubular member from the outside or the working medium (heavy liquid, light liquid) to flow out to the outside, and eventually the volume of the working medium increases or decreases (that is, the liquid level). (The position of) fluctuates) can be suppressed. As a result, highly accurate measurement is possible over the medium to long term.

According to the present invention, highly accurate measurement is possible over a medium to long term.

It is an whole view of the measuring apparatus which concerns on embodiment of this invention. It is a figure for demonstrating the detection part constituting the measuring apparatus which concerns on embodiment of this invention, (a) is a plan view, (b) is a sectional view corresponding to YY of (a). , (C) are cross-sectional views corresponding to X1-X1 of (a), and (d) is a cross-sectional view corresponding to X2-X2 of (a). In (a) to (d), the description of the protective liquid contained in the case portion and the liquid (mainly the working medium) contained in the first tubular member and the second tubular member is omitted. It is an image diagram of the detection unit main body. It is a front view of the display part which constitutes the measuring apparatus which concerns on embodiment of this invention. It is a figure for demonstrating the operation principle of the measuring apparatus which concerns on embodiment of this invention, (a) shows the state before displacement occurrence, (b) shows the state after displacement occurrence. It is a figure for demonstrating the adjustment process of the measuring apparatus which concerns on embodiment of this invention, (a) shows the state before carrying out the 1st step, (b) is the state after carrying out 1st step. , (C) shows the second step, and (d) shows the third step. It is a graph which showed the measured displacement with time in the conventional measuring apparatus. It is a graph which shows the result of the liquid level stability confirmation test by the resin tube which performed the pretreatment to absorb water, (a) is the result of the liquid level stability confirmation test of a light liquid, (b) is a heavy liquid. It is the result of the liquid level stability confirmation test of. It is a graph which shows the result of the liquid level stability confirmation test under the dry condition and the inundation condition. It is a figure for demonstrating the liquid level stability confirmation test of a double tube structure, (a) is a schematic diagram of a test piece, (b) is the result of the liquid level stability confirmation test of a double tube structure. It is a graph which shows. It is a graph which shows the result of the liquid level stability confirmation test using the high-concentration ethylene glycol aqueous solution. It is a graph which shows the result of the liquid level stability confirmation test by the double pipe structure measuring apparatus.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings as appropriate. Each figure is merely schematically shown to the extent that the present invention can be fully understood. Therefore, the present invention is not limited to the illustrated examples. In each figure, common components and similar components are designated by the same reference numerals, and duplicate description thereof will be omitted.

<Configuration of measuring device according to the embodiment>
The configuration of the measuring device 1 according to the embodiment will be described with reference to FIG. The measuring device 1 measures the vertical displacement of the object to be measured. The displacement is a relative distance in the vertical direction with respect to a certain reference point, for example, the difference between the position of the object to be measured at the first time and the position of the object to be measured at the second time. The object to be measured is not particularly limited as long as it is displaced in the vertical direction with the passage of time. The measuring device 1 according to the embodiment is effective for measuring the displacement of a structure in an invisible or difficult-to-see place such as underground or underwater.

Here, as shown in FIG. 1, it is assumed that the measuring device 1 is used for measuring the displacement of the invert portion 2a of the tunnel 2 under construction. In a ground with a large overburden, an expansive ground, or the like, a large external pressure acts on the invert portion 2a, so that a phenomenon in which the invert portion 2a rises may occur. In the present embodiment, the position (displacement) of the invert portion 2a after a predetermined time elapses is measured with the position of the invert portion 2a immediately after the construction as a reference point. The invert portion 2a here is buried in the roadbed 3 and cannot be visually recognized.

The measuring device 1 is a liquid column type measuring instrument that measures the amount of vertical displacement of the object to be measured as the amount of change in the height of the liquid as the working medium. In the measuring device 1 in the present embodiment, two types of liquids having different specific densities are used as the working medium. In the following, of the two types of liquids, a liquid having a heavy specific gravity is referred to as a "heavy liquid", and a liquid having a light specific gravity is referred to as a "light liquid". In this embodiment, the heavy liquid corresponds to the "first liquid" and the light liquid corresponds to the "second liquid".

As shown in FIG. 1, the measuring device 1 has a detection unit 10 installed at a measurement point P of an invert unit 2a, which is an object to be measured, and a display unit in which the displacement of the invert unit 2a is displayed as a change in the position of the liquid surface. 20 is provided with a connecting unit 30 for connecting the detection unit 10 and the display unit 20. The display unit 20 is installed at a position higher than the measurement point P (that is, a position higher than the detection unit 10) and where vertical displacement does not occur (even if it occurs, it is minute) over time. Ru. The display unit 20 is installed, for example, on the side wall 2b of the tunnel 2.

The detection unit 10 is installed at the measurement point P (see FIG. 1), and as shown in FIG. 2, includes a detection unit main body 10a and a case unit 10b for accommodating the detection unit main body 10a inside. The inside of the case portion 10b is filled with a protective liquid (not shown) (that is, the protective liquid is sealed in the case portion 10b). Therefore, the detection unit main body 10a is in a state of being immersed in the protective liquid. The protective liquid plays a role of isolating the working medium from the surrounding environment (atmosphere, groundwater, etc.) and suppresses unintended fluctuations in the liquid level. Unintended fluctuations in the liquid level occur, for example, when the working medium flows out into the atmosphere or when moisture in the atmosphere is absorbed by the working medium. The case portion 10b may be any as long as it can protect the detection unit main body 10a and can be installed so as not to move from the measurement point P, and the shape and the like are not particularly limited. The case portion 10b has a structure having watertightness so that the enclosed protective liquid does not leak to the outside. The detection unit main body 10a is fixed to the inside of the case unit 10b by the fixing means 10c (see FIGS. 2 (b) and 2 (d)). The fixing means shown in FIG. 2 is a bolt. The protective liquid is an example of a protective material.

As shown in FIGS. 2A and 2B, the case portion 10b includes a cylindrical main body member 16, a first closing member 17 that closes one (one end side) of the main body member 16, and the main body member 16. A connecting member 18 connected to the other side (the other end side) and a second closing member 19 for closing one of the connecting members 18 are provided. The configuration of the case portion 10b shown in FIG. 2 is merely an example, and other configurations may be used. The material of the case portion 10b is not particularly limited and may be made of, for example, metal or resin.

The members constituting the case portion 10b are joined by a taper screw for pipes. The taper screw for pipes is a conical screw and becomes thinner toward the tip. Male threads are formed on both outer peripheral surfaces of the main body member 16, female threads are formed on the inner peripheral surfaces of the first blocking member 17, and female threads are formed on both inner peripheral surfaces of the connecting member 18. , Male threads are formed on the outer peripheral surface of the second closing member 19. By screwing the pipe taper screw formed in the case portion 10b with an appropriate torque, the watertightness in the case portion 10b is ensured.

The second closing member 19 includes a partition portion 19a that divides the internal space into two in the axial direction. A screw hole is formed in the partition portion 19a, and the detection portion main body 10a is fastened to the second closing member 19 by using the fixing means 10c. Further, a circular opening is formed in the second closing member 19, and the first connector 32 of the connecting portion 30 is connected via the opening. The connecting portion between the case portion 10b and the connecting portion 30 may have a structure capable of ensuring watertightness, and the connecting method between the case portion 10b and the connecting portion 30 is not particularly limited. The first connector 32 has a structure including, for example, a cable gland.

As shown in FIGS. 2 (a) and 2 (b), the detection unit main body 10a mainly contains the first tubular member 11 containing heavy liquid, the second tubular member 12 mainly containing light liquid, and the first. It is configured to include a folded-back portion 13 that connects the tubular member 11 and the second tubular member 12 so as to communicate with each other. Since the folded-back portion 13 is a component provided for facilitating the manufacture of the detection unit main body 10a, the detection unit main body 10a may be configured not to include the folded-back portion 13. In this embodiment, the inner diameters of the first tubular member 11 and the second tubular member 12 are the same. Further, as shown in FIG. 2, at least one of the first tubular member 11 and the second tubular member 12 (here, the second tubular member 12) is multiplely wound in the case portion 10b to form a coil portion. 14 is formed. In FIG. 2, the folded-back portion 13 is located inside the coil portion 14, but the folded-back portion 13 may be located at another location.

With reference to FIG. 3, the configuration of the detection unit main body 10a (particularly, the liquid contained in the first tubular member and the second tubular member will be described.
As shown in FIG. 3, in the present embodiment, an isolated silicone oil that separates the heavy liquid and the light liquid so as not to be mixed is contained between the heavy liquid and the light liquid. Isolation silicone oil is an example of a separation liquid. The amount of the isolated silicone oil is not particularly limited, and it is preferable that the amount of the isolated silicone oil is the minimum amount at which the heavy liquid and the light liquid are not mixed. As a result, the coil portion 14 in the present embodiment has a heavy liquid side boundary portion K1 which is an interface between the heavy liquid and the isolated silicon oil and a light liquid side boundary portion K2 which is an interface between the light liquid and the isolated silicon oil. It is formed. By using the isolated silicon oil having a predetermined viscosity, the heavy liquid side boundary portion K1 and the light liquid side boundary portion K2 can be appropriately formed regardless of the viscosity of the heavy liquid or the light liquid. If the heavy liquid and the light liquid do not mix with each other, it is not necessary to provide the isolation silicone oil (that is, the heavy liquid and the light liquid may come into contact with each other to form an interface. ).

The boundary portion between the heavy liquid and the light liquid (here, the region from the heavy liquid side boundary portion K1 to the light liquid side boundary portion K2, hereinafter referred to as “boundary portion K”) is the “measurement step” described later. Or move in the first tubular member 11 and the second tubular member 12 in the “adjustment step of the measuring device”. In the present embodiment, the boundary portion K does not move to the outside of the coil portion 14 (connecting portion 30). That is, the number of turns N of the coil portion 14 and the length per winding (length corresponding to the circumference) are set so that the boundary portion K does not move to the outside of the coil portion 14. .. The amount of movement of the boundary portion K is determined by the difference in specific gravity between the heavy liquid and the light liquid, the distance L from the detection unit 10 to the display unit 20 (see FIG. 1), and the like.

The folded-back portion 13 includes a heavy liquid side connecting portion 13a, a light liquid side connecting portion 13b, and a U-shaped tube 13c. The end portion of the first tubular member 11 is attached to the heavy liquid side connection portion 13a, and the end portion of the second tubular member 12 is attached to the light liquid side connection portion 13b. Since the first tubular member 11 and the second tubular member 12 communicate with each other via the folded-back portion 13, the liquid in the first tubular member 11, the second tubular member 12, and the U-shaped tube 13c can move to each other. Is. By removing either the heavy liquid side connection portion 13a or the light liquid side connection portion 13b, the liquid can be injected into the first tubular member 11, the second tubular member 12, and the folded portion 13, and the first. The liquid in the tubular member 11, the second tubular member 12, and the folded portion 13 can be discharged.

Returning to FIG. 2, the description of the detection unit 10 will be continued. The coil portion 14 in the present embodiment is formed by winding the second tubular member 12 around the core member 15. The core member 15 may be such that at least one of the first tubular member 11 and the second tubular member 12 (here, the second tubular member 12) can be wound, and the wound tubular members 11 and 12 can be used as much as possible. It is desirable that the structure can be kept horizontal (that is, the structure in which the inclination of the tubular members 11 and 12 with respect to the horizontal is small).

As shown in FIGS. 2 (c) and 2 (d), the core member 15 of the present embodiment includes a bottom plate 15a, a top plate 15b, a guide 15c provided between the bottom plate 15a and the top plate 15b, and a bottom plate 15a. It is provided with a support portion 15d provided on the lower side.
Both the bottom plate 15a and the top plate 15b have a rectangular shape and are parallel to each other. The bottom plate 15a has a larger long side dimension than the top plate 15b, and is slightly longer than the top plate 15b.

The guide 15c is a portion around which the tubular members 11 and 12 are wound, and has a shape (half) in which the cylinder is halved in the axial direction (in other words, both ends of the rectangular plate are curved in a C shape so as to be close to each other). It has a split cylindrical shape). The guides 15c are arranged so as to face each other near both ends of the bottom plate 15a, and guide the tubular members 11 and 12 to form a curve. In addition to the guide 15c shown in FIG. 2, fixing means for fixing the tubular members 11 and 12 to the core member 15 may be provided.

The support portion 15d has a curved surface that abuts on the inner peripheral surface of the case portion 10b so that the core member 15 does not rattle in the case portion 10b. The support portion 15d is arranged near both ends of the bottom plate 15a, and the support portion 15d on the connecting portion 30 side is fixed to the case portion 10b by the fixing means 10C.

As shown in FIG. 1, the connecting portion 30 connects the detection unit 10 and the display unit 20, and is installed along the invert portion 2a and the side wall 2b of the tunnel 2 in the present embodiment. .. The method of installing the connecting portion 30 is not limited to that shown in FIG. As shown in FIGS. 2A and 2B, the connecting portion 30 includes a first tubular member 11 containing a heavy liquid, a second tubular member 12 containing a light liquid, a first tubular member 11, and a first tubular member 11. (Ii) It is composed of a protective tube 31 that protects the tubular member 12. The first tubular member 11 and the second tubular member 12 here are cylindrical tubes. That is, the connecting portion 30 has a double structure of the first tubular member 11 or the second tubular member 12 and the protective tube 31.

The inside of the protective tube 31 is filled with a protective liquid (not shown) (that is, the protective liquid is sealed in the protective tube 31). Therefore, the first tubular member 11 and the second tubular member 12 are in a state of being immersed in the protective liquid. The protective liquid plays a role of isolating the working medium from the surrounding environment (atmosphere, groundwater, etc.) and suppresses unintended fluctuations in the liquid level. The protective tube 31 has a watertight structure so that the enclosed protective liquid does not leak to the outside. Specifically, a first connector 32 (see FIGS. 2A and 2B) and a second connector 33 (see FIG. 4) are provided at both ends of the protective tube 31. The first connector 32 and the second connector 33 have a structure including, for example, a cable gland.

As shown in FIG. 4, the first tubular member 11 containing the heavy liquid and the second tubular member 12 containing the light liquid are fixed to the display unit 20 side by side so as to extend in the vertical direction. Further, the display unit 20 is provided with a scale plate 25 having a scale 25a for reading the position of the surface of the liquid on the measurement side (here, the liquid level B2a of the light liquid). The scale plate 25 is an example of a reading means, and the reading means is not limited to the scale plate 25. The scale 25a is set to a zero point 25b at which the liquid level B2a of the light liquid is adjusted before the displacement occurs. In order to make it easier to read the position of the liquid level B2a of the light liquid, the liquid level B2a of the light liquid may be colored with a color that is easy to see, or the liquid level of the light liquid may be colored with a colored liquid (for example, oil). B2a may be covered.

A first valve 21 is attached to the end of the first tubular member 11, and the end of the first tubular member 11 can be opened and closed. The details will be described later, but at the time of measurement, the liquid level B1a of the heavy liquid is located at a place away from the end portion of the first tubular member 11. The heavy liquid exhibits a columnar shape in the first tubular member 11, and may be referred to as a "heavy liquid column" in the following.

The second tubular member 12 is branched into a first branch pipe 12a and a second branch pipe 12b by a branch portion 22. A second valve 23 is attached to the end of the first branch pipe 12a, and the end of the first branch pipe 12a can be opened and closed. The details will be described later, but at the time of measurement, the liquid level B2a of the light liquid is located at a place away from the end of the first branch pipe 12a. The light liquid exhibits a columnar shape in the first branch pipe 12a, and may be referred to as a "light liquid column" in the following. Further, a discharge nozzle 24a having an inner diameter much smaller than that of the second branch pipe 12b is attached to the end of the second branch pipe 12b via the third valve 24. The details will be described later, but the excess light liquid generated when the measuring device 1 is adjusted to the usable initial state is discharged from the discharge nozzle 24a. The tip of the discharge nozzle 24a is aligned with the zero point 25b of the scale plate 25.

(Operating principle of measuring device)
The operating principle of the measuring device 1 will be described with reference to FIG. FIG. 5 is a schematic diagram showing the head balance of the two liquid columns (heavy liquid column and light liquid column).
Consider a case where liquid columns consisting of two types of liquids having different specific densities and immiscible (miscible) are in contact with each other in a liquid pool as shown in FIG. As shown in FIG. 5A, if the height of the head of the heavy liquid is "H", the height of the head of the light liquid is balanced at the position of "(ρ _h / ρ _l ) · H". “Ρ _h ” is the specific density of the heavy liquid, and “ρ _l ” is the specific gravity of the light liquid. Further, the height "Hc" of the liquid pool is assumed to be negligibly smaller than the height "H". In the measuring device 1 shown in FIG. 1, for the purpose of improving the stability of the liquid pool and reducing the temperature dependence, the liquid pool has a coil structure in which tubular members are wound in multiple layers instead of a tank structure.

Here, as shown in FIG. 5B, when a vertical displacement "x" occurs in the liquid pool, the balance of each head is lost, and in order to cancel the imbalance in the balance, each head is "x". It changes by "ΔH _h , ΔH _l ".
At this time, the balance between the two heads is expressed by the following equation (1).
(Hx + ΔH _h ): {(ρ _h / ρ _l ) · Hx + ΔH _l } = ρ _l : ρ _h ··· Equation (1)
Further, since the volumes of the liquid moving between the two liquid columns are the same, the following equation (2) holds. Here, "A _h " is the area of the liquid column of the heavy liquid, and "A _l " is the area of the liquid column of the light liquid.
(A _h・ ΔH _h ) = (-1 ・_{Al ・ ΔH l )}・ ・ Equation (2)

From the equations (1) and (2), the relationship between the change amount “ΔH _l ” of the light liquid column and the displacement “x” of the liquid pool is as shown in the following equation (3).
ΔH _l = (ρ _l －ρ _h ) / {ρ _l + ρ _h・ (A _l / A _h )} ・ x ・ ・ Equation (3)
That is, if "ΔH _l " (or "ΔH _h " may be used) can be known, the displacement "x" of the liquid pool can be known. In addition, the larger the difference in specific gravity between the two types of liquid and the thinner the light liquid injection than the heavy liquid injection, the better the sensitivity of the change amount "ΔH _l " of the light liquid column to the displacement "x" of the liquid pool. .. However, if the pipe accommodating the liquid column is too thin, the movement of the liquid column will be impaired due to the viscous resistance of the liquid.

(Manufacturing method of measuring device)
The measuring device 1 can be manufactured by using various materials. In particular, the heavy liquid, the light liquid, and the materials of the first tubular member 11 and the second tubular member 12 for accommodating these liquids are important because they are related to the accuracy of the measured displacement amount. In addition, although the protective liquid is not directly related to the accuracy of the displacement amount, it prevents the heavy liquid and the light liquid, which are the working medium, from flowing out into the atmosphere and the moisture in the atmosphere from being absorbed by the working medium. This is important because it maintains high-precision measurement over the medium to long term. Furthermore, when selecting materials, it is necessary to consider the compatibility of each material in addition to specifying individual materials. The following is an example of materials that can be used in the measuring device 1.

As the light liquid, for example, spindle oil, silicone oil, water, or ethylene glycol can be used.
As the heavy liquid, for example, a NaNO ₃ + Ca (NO ₃ ) ₂ mixed aqueous solution, a ZnCl ₂ solution, and a sodium polytungstate (SPT) aqueous solution can be used.

In the protective liquid, the volume of the working medium increases or decreases (that is, when a substance flows into the first tubular member 11 or the second tubular member 12 from the outside or the working medium (heavy liquid, light liquid) flows out to the outside. Anything that can suppress (the position of the liquid level fluctuates) is sufficient. The suppression here is not intended that the volume of the working medium does not permanently increase or decrease due to the inflow of the substance or the outflow of the working medium, and allows the inflow of a predetermined amount of the substance or the outflow of the working medium over time. Is what you do. That is, the protective liquid includes the measurement accuracy within the measurement period within the presumed allowable range by keeping the increase / decrease of the working medium within the predetermined amount within the predetermined measurement period (for example, several months). It is intended to be sustainable. The measurement period and measurement accuracy may be determined according to the purpose of measurement and the like.

The protective liquid is not limited to substances that are not mixed with the working medium (heavy liquid, light liquid). The protective liquid may be a liquid different from the heavy liquid and the light liquid as the working medium, or a liquid containing the same components as either the heavy liquid or the light liquid (the solvent and the solute components are the same and the concentration is the same). (Including different ones). When a liquid having the same composition is used as the working medium and the protective liquid, it is assumed that the concentration of the working medium changes due to the mixing of the working medium and the protective liquid, but the increase / decrease in the volume of the working medium is allowed as described above. It allows a predetermined amount of change in concentration over time.

In the present embodiment, as described above, the first tubular member 11 and the second tubular member 12 are housed in one protective tube 31 in the connecting portion 30, and the first tubular member 11 and the second tubular member 12 are housed in the detecting portion 10. It is stored in one case portion 10b. That is, in the connecting portion 30 and the detecting portion 10, the first tubular member 11 and the second tubular member 12 are housed in one space that is not physically divided, and the space is filled with the protective liquid to fill the first tubular member. The circumference of the 11 and the second tubular member 12 is covered with one kind of liquid. In the case of such a structure, the effect of suppressing the increase / decrease in the volume of the working medium (light liquid) by emphasizing the working medium (for example, light liquid) on the side where the volume fluctuation due to the inflow of the substance or the outflow of the working medium is larger. It is effective to use a certain protective solution.

Further, the protective liquid to be used may be determined with more emphasis on the relationship with the first tubular member 11 and the second tubular member 12 than the relationship with the working medium (heavy liquid, light liquid). Furthermore, considering the compatibility of the materials of the working medium (heavy liquid, light liquid), the first tubular member 11, the second tubular member 12, and the protective liquid, a combination that suppresses the deterioration of measurement accuracy overall is selected. You may. As the protective liquid, for example, spindle oil, silicon oil, water, ethylene glycol, NaNO ₃ + Ca (NO ₃ ) ₂ mixed aqueous solution, ZnCl ₂ solution, and sodium polytungstate (SPT) aqueous solution can be used.

Preferred characteristics of the materials of the first tubular member 11 and the second tubular member 12 are low temperature expansion rate, impermeable (or difficult to permeate) light liquid or heavy liquid, light liquid, heavy liquid. It does not chemically react (or has a small effect) with the liquid or isolated silicon oil, and has high durability.
As the material of the first tubular member 11 and the second tubular member 12, for example, nylon, polyolefin, fluororesin (FEP, PFA), polypropylene, and stainless steel can be used.

<Measurement method using the measuring device according to the embodiment>
A method of measuring displacement using the measuring device 1 according to the embodiment will be described with reference to FIGS. 1 to 6. The process of the measurement method mainly includes "preparation process of measurement device", "installation process of measurement device", "adjustment process of measurement device", and "measurement process using measurement device". Hereinafter, each step will be described.

(Preparation process of measuring device)
The “measurement device preparation step” is a step of preparing the measuring device 1. In this step, for example, a heavy liquid is injected into the first tubular member 11 and a light liquid is injected into the second tubular member 12. Further, the folded-back portion 13 is removed, and the isolated silicone oil is injected between the heavy liquid and the light liquid. After containing the heavy liquid, the light liquid and the isolated silicone oil, the first valve 21, the second valve 23 and the third valve 24 are closed. Further, the inside of the case portion 10b and the protective tube 31 is filled with the protective liquid.

(Installation process of measuring device)
The "measurement device installation process" is a process of installing the measurement device 1. In this step, for example, as shown in FIG. 1, the detection unit 10 is installed at the measurement point P of the invert unit 2a, which is the object to be measured, and the connecting unit 30 is installed along the invert unit 2a and the side wall 2b. .. Further, the display unit 20 is installed on the side wall 2b where vertical displacement does not occur (even if it does occur, it is minute) with the passage of time.

(Adjustment process of measuring device)
The "adjustment step of the measuring device" is a step of adjusting the measuring device 1 to a usable initial state. In this step, as shown in FIG. 6A, the first valve 21 and the third valve 24 are opened. The second valve 23 is left closed. As a result, as shown in FIG. 6B, the liquid level B1a of the heavy liquid column reaches a position where the liquid level B1a of the heavy liquid column (see FIG. 4) and the liquid level B2a of the light liquid column (see FIG. 4) are balanced. (See FIG. 4) decreases. Along with this, the excess light liquid is discharged from the discharge nozzle 24a, and the isolated silicon oil moves in the coil portion 14 toward the light liquid column side. In the present embodiment, since the first tubular member 11 and the second tubular member 12 constituting the coil portion 14 are sufficiently long, even if the isolated silicone oil moves, the boundary portion K (see FIG. 3). Does not move to the outside of the coil portion 14. As a result, the liquid level B1a of the heavy liquid column moves to a position lower than the zero point 25b (see FIG. 4) of the scale plate 25.

Subsequently, as shown in FIG. 6C, the first valve 21 is closed and the second valve 23 is opened. The third valve 24 is left open. As a result, the liquid level B2a (see FIG. 4) of the light liquid column is lowered to the zero point 25b (see FIG. 4) of the scale plate 25. Along with this, the excess light liquid is discharged from the discharge nozzle 24a.

Subsequently, as shown in FIG. 6D, the first valve 21 is opened and the third valve 24 is closed. The second valve 23 is left open. This completes the adjustment process of the measuring device.

(Measurement process using measuring device)
The “measurement step using the measuring device” is a step of measuring the vertical displacement of the measuring point P using the measuring device 1. This step is performed, for example, at predetermined time intervals. In this step, the operator (see FIG. 1) confirms the position of the liquid level B2a (see FIG. 4) of the light liquid column using the scale plate 25, and the detection unit 10 according to the above-described formula (3). The position is calculated as the position of the measurement point P. Then, for example, it is determined whether or not the displacement amount of the measurement point P is within the allowable range, and if the displacement amount exceeds the allowable range, appropriate measures such as spraying concrete on the invert portion 2a are taken. .. In this embodiment, since the first tubular member 11 and the second tubular member 12 constituting the coil portion 14 are sufficiently long, it is assumed that the isolated silicone oil moves with the displacement of the measurement point P. However, the boundary portion K (see FIG. 3) does not move to the outside of the coil portion 14.

<Explanation of the effect of the measuring device according to the embodiment>
As described above, in the measuring device 1 according to the present embodiment, the displacement amount of the detection unit 10 appears as the amount of change in the liquid level due to the difference in the specific gravity of the two types of liquids (heavy liquid and light liquid). Therefore, the amount of displacement of the measurement point P in the vertical direction can be measured. Since the measuring device 1 according to the present embodiment does not require a water pressure gauge or a power source, the configuration is simple and it is not easily restricted by the usage environment, so that the degree of freedom of use is higher than before.

Further, in the measuring device 1 according to the present embodiment, even when the heavy liquid and the light liquid move due to the displacement of the detection unit 10, the boundary portion K between the heavy liquid and the light liquid orbits in the coil portion 14. do. That is, since the boundary portion K does not move away from the measurement point P to the connecting portion 30, the boundary portion K is always present near the measurement point P. Therefore, the amount of displacement of the measurement point P in the vertical direction can be measured with high accuracy.

Further, in the measuring device 1 according to the present embodiment, since the periphery of the first tubular member 11 and the second tubular member 12 is filled with the protective liquid, the influence of the installation environment affects the first tubular member 11 and the second tubular member 11. It is difficult to reach the inside of 12. That is, it becomes difficult for a substance to flow into the first tubular member 11 or the second tubular member 12 from the outside or the working medium (heavy liquid, light liquid) to flow out to the outside, and eventually the volume of the working medium increases or decreases (that is,). The position of the liquid level fluctuates) can be suppressed. As a result, highly accurate measurement is possible over the medium to long term.

The inventor of the present invention has tested the factors that cause the accuracy of the conventional measuring device to decrease with the passage of time and the effect of covering the first tubular member 11 and the second tubular member 12 with the protective liquid. With reference to FIGS. 7 to 12, the factors that cause the accuracy of the conventional measuring device to decrease with the passage of time and the effect of covering the first tubular member 11 and the second tubular member 12 with the protective liquid will be described.

FIG. 7 shows the measured displacement over time when the conventional measuring device in which the first tubular member 11 and the second tubular member 12 are exposed to the atmosphere is placed under certain conditions (room temperature of about 19 ° C to 24 ° C). It is a graph showing. In FIG. 7, the horizontal axis is the number of elapsed days, and the vertical axis is the measured displacement of the liquid level (or the room temperature at the time of measurement). In the test of FIG. 7, since the detection unit 10 is stationary in a place where vertical displacement does not occur with the passage of time, the displacement amount of the liquid level on the vertical axis should not change, but for some reason. It fluctuates depending on. In FIG. 7, a positive displacement amount indicates a sinking direction (downward direction) of the liquid level of the light liquid, and a negative displacement amount indicates an ascending direction of the liquid level of the light liquid.

In the measurement shown in FIG. 7, three test specimens having different materials (or the same components but different concentrations) of the heavy liquid, the light liquid, and the tubular members 11 and 12 containing these liquids were prepared. Hereinafter, these three test specimens are referred to as "standard type", "high sensitivity type", and "standard S type".

The standard type is a measuring device using "34% sodium nitrate aqueous solution" as a heavy liquid, "38% ethylene glycol aqueous solution" as a light liquid, and "polypropylene" as tubular members 11 and 12.
The high-sensitivity type is "77% sodium polytungstate (SPT) aqueous solution" as a heavy liquid, "15% ethylene glycol aqueous solution" as a light liquid, and "fluororesin (PFA (ethylene tetrafluoride par)" as tubular members 11 and 12. It is a measuring device using (abbreviation of fluoroalkoxyethylene copolymer resin)) ”.
The standard S type is a measuring device using "70% zinc chloride aqueous solution" as a heavy liquid, "84% ethylene glycol aqueous solution" as a light liquid, and "polyethylene" as tubular members 11 and 12.

As shown in FIG. 7, the liquid level of the light liquid decreased in the standard type and the high-sensitivity type, and the liquid level of the light liquid increased in the standard S type. From this result, the inventor of the present invention hypothesized that the liquid level of the working medium changes with time due to the following two factors.
(Factor 1) The resin tubular members 11 and 12 absorb water inside the liquid (working medium), and the liquid level drops with time.
(Factor 2) Light ethylene glycol absorbs water in the atmosphere and the liquid level rises over time (ethylene glycol has the function of absorbing water in the atmosphere and raising the liquid level).
In other words, it was speculated that the liquid level of the light liquid was lowered by factor 1 in the standard type and high-sensitivity type (although there was also the influence of factor 2, the concentration of ethylene glycol used in the light liquid in the standard type and high-sensitivity type). Was as low as "38% or 15%", and the effect was minor).
On the other hand, the concentration of ethylene glycol used in the light liquid in the standard S type is "84%", which is higher than that of other types (38% and 15%), so the influence of factor 2 is larger than that of factor 1. It was speculated that the liquid level of the light liquid had risen.

Next, the inventor thinks that it may be possible to prevent the liquid level from dropping due to factor 1 by allowing the tubular members 11 and 12 to absorb water in advance to bring them into a saturated state, and the pretreatment for causing the tubular members 11 and 12 to absorb water. After that, a liquid level stability confirmation test was conducted.
Specifically, a resin tube was filled with water, and after standing in a constant temperature bath at 80 ° C. for 24 hours, the water inside was discharged and filled with a light liquid and a heavy liquid. In this test, assuming a high-sensitivity type, the heavy liquid is "77% sodium polytungstate (SPT) aqueous solution", the light liquid is "15% ethylene glycol aqueous solution", and the tube is "fluororesin (PFA (ethylene tetrafluoride)." Abbreviation for perfluoroalkoxy ethylene copolymer resin)) ”was used.

FIG. 8 shows the results of a liquid level stability confirmation test using a tube that has been pretreated to absorb water. FIG. 8A is the result of the liquid level stability confirmation test of the light liquid, and FIG. 8B is the result of the liquid level stability confirmation test of the heavy liquid. The liquid level stability confirmation test is conducted in a room where temperature and humidity are not controlled. The indoor temperature during the test period is in the range of about 23 ° C to 30 ° C, and the humidity in the test area is about 60% to 100%. It was in the range of. The line graph shown by PFA (light liquid) in FIG. 8 (a) is the actual measured value, and the line graph shown by PFA light liquid (constant temperature bath 23.6 ° C.) in FIG. 8 (a) is a liquid due to temperature change. The liquid level at 23.6 ° C was calculated by calculation in consideration of the thermal expansion rate in order to eliminate the influence of surface fluctuation. Similarly, the line graph shown by PFA (heavy liquid) in FIG. 8 (b) is the actual measured value, and the line graph shown by PFA heavy liquid (constant temperature bath 24.1 ° C.) in FIG. 8 (b) is due to temperature change. In order to eliminate the influence of liquid level fluctuation, the liquid level height at 24.1 ° C was calculated in consideration of the thermal expansion rate.
As shown in FIG. 7, when the pretreatment for water absorption is not performed, the liquid level of the light liquid fluctuates from the first day of the test in all types including the high-sensitivity type (even for the heavy liquid according to the principle shown in FIG. 5). However, as shown in FIG. 8, when the pretreatment for water absorption is performed, the liquid level is stable for about 30 days for the light liquid (ethylene glycol) and for about 70 days for the heavy liquid (SPT solution). Can be confirmed.

As shown in FIG. 8, it was found that the problem of liquid level drop due to factor 1 was improved by performing the pretreatment of absorbing water in the resin tube, but the liquid level was still lowered in the long-term measurement. .. Therefore, the inventor hypothesized that the resin tube not only absorbs water but also the liquid (working medium) inside the tube flows out from the inside to the outside, and the drying conditions of the tube filled with the liquid are set. Further, a liquid level stability confirmation test was conducted under flooded conditions. Specifically, a test piece filled with water in a tube made of fluororesin (PFA) is prepared, and the test piece is subjected to drying conditions (10 to 15% RH (relative humidity: Relative Humidity)) and water. The test was conducted under flooded conditions submerged in.

The results of the liquid level stability confirmation test under dry conditions and flooded conditions are shown in FIG. As shown in FIG. 9, the liquid level did not decrease under the water immersion condition, but the liquid level decreased under the dry condition. Since a layer of silicon oil is provided on the liquid surface, there is almost no outflow of liquid (here, water) from the open portion to the atmosphere.

From the results of the tests so far, it was found that the liquid level does not drop by filling the outside of the resin tube (that is, the tubular members 11 and 12) with the liquid. We devised a double-tube structure in which the outside of 11 and 12 was filled with liquid, and conducted a verification test (liquid level stability confirmation test of the double-tube structure) to confirm the effect.

The liquid level stability confirmation test of the double tube structure will be described with reference to FIG. 10. FIG. 10 (a) is a schematic view of the test piece used for the liquid level stability confirmation test of the double tube structure, and FIG. 10 (b) shows the results of the liquid level stability confirmation test of the double tube structure. It is a graph which shows.

As shown in FIG. 10 (a), the test body 100 in this test contains a cylindrical tube 111 for accommodating a heavy liquid, a cylindrical tube 112 for accommodating a light liquid, and tubes 111 and 112. It mainly comprises a CD (Combined Duct) tube 101 and a liquid 104 filled in the CD tube 101. The CD pipe 101 is a synthetic resin pipe for burying concrete. The tips of the tubes 111 and 112 are closed, and a layer of silicone oil is provided on the liquid surface. The tip of the CD tube 101 is closed by the terminal obstruction portion 102, and the terminal obstruction portion 102 is provided with a valve 103 for filling the liquid 104 into the CD tube 101.

In the liquid level stability confirmation test of the double tube structure, assuming a high sensitivity type, "77% sodium polytungstate (SPT) aqueous solution" as a heavy liquid, "15% ethylene glycol aqueous solution" as a light liquid, in the CD tube 101 As the liquid 104 to be filled in, a "20% ethylene glycol aqueous solution" containing the same components as the light liquid and having different concentrations was used. The tubes 111 and 112 are made of fluororesin (PFA). The reason why the ethylene glycol aqueous solution is adopted for the liquid 104 is that when water is used, the liquid level fluctuates due to the influence of the osmotic pressure with the liquid in the tubes 111 and 112.

FIG. 10 (b) shows changes in the liquid level with the passage of time when the test piece 100 is allowed to stand in a constant temperature and humidity chamber at 30 ° C. and 10 to 15% RH. As shown in FIG. 10B, the result was that the liquid level did not fluctuate with the passage of time.

In addition, the inventor used a high-concentration ethylene glycol aqueous solution to verify factor 2 (a light ethylene glycol absorbs moisture in the atmosphere and the liquid level rises over time). A stability confirmation test was performed. Specifically, a 99.5% ethylene glycol solution was filled in a tube made of polypropylene, fluororesin (PFA) and polyethylene, and the fluctuation of the liquid level with the passage of time was measured.

FIG. 11 shows the results of a liquid level stability confirmation test using a high-concentration ethylene glycol aqueous solution. In FIG. 11, the horizontal axis is the number of elapsed days, and the vertical axis is the measured liquid level fluctuation (or the room temperature at the time of measurement). The line graph shown by PP (polypropylene) in FIG. 11 is the actual measured value, and the point shown by PP (constant temperature bath 22.3 ° C) in FIG. 11 is thermal expansion in order to eliminate the influence of liquid level fluctuation due to temperature change. The liquid level at 22.3 ° C was calculated in consideration of the rate. Similarly, the line graph shown by PFA (fluorine) in FIG. 11 is the actual measured value, and the point shown by PFA (constant temperature bath 22.3 ° C) in FIG. 11 is heat to eliminate the influence of liquid level fluctuation due to temperature change. The liquid level at 22.3 ° C was calculated in consideration of the expansion rate. Similarly, the line graph shown by PE (polyethylene) in FIG. 11 is the actual measured value, and the point shown by PE (constant temperature bath 22.3 ° C) in FIG. 11 is heat to eliminate the influence of liquid level fluctuation due to temperature change. The liquid level at 22.3 ° C was calculated in consideration of the expansion rate.
As shown in FIG. 11, the liquid level of all the tubes made of polypropylene, fluororesin (PFA) and polyethylene increased with time. From this result, it is inferred that ethylene glycol has a hygroscopic property, so that it absorbs moisture in the atmosphere and the liquid level rises. For this problem (problem of factor 2), it was confirmed that the liquid level can be prevented from rising by using ethylene glycol having the same concentration as the light liquid ethylene glycol as the above-mentioned double tube structure. did.

From the above test results, the inventor manufactured a measuring device having a double tube structure similar to that of the measuring device 1 shown in FIG. 2, and used the measuring device for a liquid level stability confirmation test (double tube structure measurement). A liquid level stability confirmation test) was performed using the device. The liquid level stability confirmation test using the double pipe structure measuring device was carried out indoors.

In the liquid level stability confirmation test using the double tube structure measuring device, "77% sodium polytungstate (SPT) aqueous solution" as a heavy liquid, "15% ethylene glycol aqueous solution" as a light liquid, and "20% ethylene glycol aqueous solution" as a protective liquid. "It was used. Further, the material of the first tubular member 11 and the second tubular member 12 is fluororesin (PFA), a CD tube is used as the protective tube 31 of the connecting portion 30, and the case portion 10b of the detecting portion 10 is made of vinyl chloride resin. Tubular member (PVC pipe) was used.

FIG. 12 shows the results of the liquid level stability confirmation test using the double pipe structure measuring device. The horizontal axis in FIG. 12 is the date on which the measurement was performed, and the vertical axis is the amount of fluctuation in the liquid level of the measured light liquid (or the room temperature at the time of measurement). As shown in FIG. 12, it was confirmed that the liquid level change for 48 days was stable within a range of 1 mm.

[Modification example]
Although the embodiments of the present invention have been described above, the present invention is not limited to this, and can be carried out without changing the gist of the claims.

In the present embodiment, the position of the liquid level B2a of the light liquid is read by using the scale plate 25, but the position of the liquid level B1a of the heavy liquid may be read. In that case, the light liquid corresponds to the "first liquid" and the heavy liquid corresponds to the "second liquid".

Further, in the present embodiment, the detection unit 10 is a coil portion in which at least one of the first tubular member 11 and the second tubular member 12 (here, the second tubular member 12) is multiplely wound in the case portion 10b. Had 14. However, even when the heavy liquid and the light liquid move due to the displacement of the detection unit 10, it is sufficient that the boundary portion K between the heavy liquid and the light liquid can be maintained in the detection unit 10 and the inside of the case unit 10b. The storage method of the first tubular member 11 and the second tubular member 12 in the above is not limited to this. For example, at least one of the first tubular member 11 and the second tubular member 12 may be housed in the case portion 10b in an S-shaped or M-shaped state. Further, as shown in FIG. 5, a tank structure may be used instead of the coil portion 14.

Further, in the embodiment, the first tubular member 11 and the second tubular member 12 are housed in one protective tube 31, but the first tubular member 11 and the second tubular member 12 are housed in separate protective tubes 31. It is also possible to do.

Further, in the embodiment, a liquid (that is, a protective liquid) is assumed as a substance that plays a role of isolating the working medium from the surrounding environment (air, groundwater, etc.). However, the substance that isolates the working medium is not limited to liquids, but may be solids or substances that are more viscous than liquids (such as "gels"). These are collectively referred to as "protective material". That is, the protective material has the same function as the protective liquid described in the embodiment, and is made of a substance other than gas. The protective material is preferably arranged in close contact with the periphery of the first tubular member 11 and the second tubular member 12. For example, the protective material includes a highly moisturizing viscous material, a cured material that cures over time to allow airtightness (eg, such as a "sealing material"), and the like. Further, the protective material has, for example, a strip shape, and may be wound around the first tubular member 11 and the second tubular member 12. If the protective material can stay around the first tubular member 11 and the second tubular member 12, it is not necessary to provide the case portion 10b of the detection unit 10 or the protective tube 31 of the connecting portion 30.

1 Measuring device 2 Tunnel 2a Invert part 10 Detection part 10a Detection part main body 10b Case part 11 First tubular member 12 Second tubular member 12a First branch pipe 12b Second branch pipe 13 Folded part 14 Coil part 15 Core member 20 Display part 21 1st valve 22 Branch 23 2nd valve 24 3rd valve 24a Discharge nozzle 25 Scale plate (reading means)
30 Connection part 31 Protective tube 32 First connector 33 Second connector P Measurement point K Boundary part

Claims (5)

It is a measuring device that measures the amount of vertical displacement of a structure as the amount of change in the height of the liquid level.
A detector installed at the measurement point and accommodating the first liquid and the second liquid with different specific densities,
A connecting portion extending from the detection portion and having a first tubular member accommodating the first liquid and a second tubular member accommodating the second liquid.
A display unit having a reading means capable of reading the position of the liquid surface of the second liquid is provided.
The detection unit has a coil unit in which at least one of the first tubular member and the second tubular member is wound in a coil shape.
A measuring device characterized in that a protective material is closely arranged around the first tubular member and the second tubular member. The protective material is a protective liquid that exhibits a liquid state, and is a protective liquid.
The detection unit includes a case portion having watertightness, and the coil portion and the protective liquid are sealed in the case portion.
The connecting portion includes a protective tube having watertightness, and the first tubular member, the second tubular member, and the protective liquid are sealed in the protective tube.
The measuring device according to claim 1. The measuring device according to claim 2, wherein the protective liquid is a liquid containing the same component as that of the first liquid and the second liquid having a lighter specific gravity. A first valve is installed at the tip of the first tubular member.
The tip end side of the second tubular member is branched into two, a first branch pipe and a second branch pipe.
A second valve is installed in the first branch pipe.
The second branch pipe is provided with a discharge nozzle for discharging the excess amount of the second liquid via the third valve.
The measuring device according to any one of claims 1 to 3, wherein the measuring device is characterized by the above. It is a measurement method that measures the amount of vertical displacement of a structure as the amount of change in the height of the liquid level.
The preparatory step for preparing the measuring device according to claim 4 and
The installation process of installing the measuring device on the structure to be measured, and
The adjustment process for adjusting the measuring device to the initial state and
It has a measurement process for measuring the amount of displacement using the measuring device, and has.
The adjustment step is
From the state where the first valve, the second valve and the third valve are closed, the first valve and the third valve are opened to lower the liquid level of the first liquid and the surplus portion. The first step of discharging the second liquid from the discharge nozzle and
From the state of the first step, the first valve is closed and the second valve is opened to lower the liquid level of the second liquid, and the surplus second liquid is further discharged from the discharge nozzle. The second process of discharging and
It has a third step of opening the first valve and closing the third valve from the state of the second step.
A measurement method characterized by that.

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