JP2002340549A - Settlement measuring instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a settlement measuring instrument, capable of more accurately measuring settled quantity, as compared with a conventional method by relaxing fluctuations in atmospheric pressure, even if receiving sudden fluctuations in atmospheric pressure generated accompanied by the passage of a train in a tunnel. SOLUTION: The settlement measuring instrument has a reference water tank 1 for keeping the water level in a hermetically closed container constant, one or more measurement pipes, a communication pipe for allowing the reference water tank and the measuring pipe to communicate with each other under the surface of the water and an air pipe allowing the hermetically closed container and the measuring pipe to communicate with each other, above the surface of the water and measures the subsidence quantity of the arranging place of the measuring pipe, on the basis of the water level of the measuring pipe. Furthermore, this apparatus has a venting means for allowing the atmosphere to freely flow between the inside of the hermetically closed container and the outside and gently relaxing the atmospheric pressure difference, between the inside and outside of the hermetically closed container by the inflow of the atmosphere into the hermetically closed container or the outflow of the atmosphere from the hermetically closed container.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a settlement measuring device for measuring the amount of settlement of a structure or the like.

[0002]

2. Description of the Related Art With reference to FIG. 3, a conventional settlement measuring apparatus will be described. The squat measurement device includes a reference water tank 101 having a constant water level, measurement pipes 102 and 103 for measuring the amount of squat due to fluctuations in the water level, and a communication pipe 104 for communicating the reference water tank 101 and the measurement pipe in water.
Consists of

A reference water tank 101 and measuring tubes 102, 1
Since the accurate measurement cannot be performed unless the air pressures at 03 are equal, the reference water tank 101 is installed with the air open to the atmosphere, and the measuring pipes 102 and 103 are connected to each other by an air pipe 105 whose end is open to the atmosphere. , Each measuring tube 102,
By setting the reference pressure 103 and the reference water tank 101 under atmospheric pressure, the pressure applied to both is equalized.

[0004] As described above, the squat measurement device can be used for measuring the squat amount of a building, a tunnel or the like because the squat amount can be evaluated relatively accurately despite its simple structure. ing.

In the settlement measuring device, a reference water tank 101 is used.
It is above all important to keep the water level constant. Evaporation of water in the reference water tank 101 and measurement tubes 102, 1
In order to prevent the water level of the reference water tank 101 from changing due to the influence of the subsidence or uplift of the water tank 03, and to keep the water level constant, water is continuously supplied from the auxiliary water tank 107 to the reference water tank 101 little by little by means of a pump 106 or the like. The reference water tank 101 always overflows to maintain a constant water level.

[0006] The measuring tubes 102 and 103 are installed at an arbitrary place where the amount of settlement is to be evaluated. If the place sinks, the water level in the measuring pipes 102 and 103 apparently rises according to the sinking amount. In addition, when the place is raised, the water level in the measurement pipes 102 and 103 apparently drops in water level according to the amount of protrusion. In this way, the reference tank 1
It is possible to judge whether the place where the measuring tubes 102 and 103 are installed relative to 01 is settled or raised.

[0007]

However, it has been difficult for the conventional settlement measuring apparatus to perform stable measurement inside the train tunnel. This is because the air pressure fluctuates rapidly as the train passes. More specifically, when measuring the atmospheric pressure with an arbitrary point in the tunnel as a measurement point,
As the train approaches, the air pressure at the measurement point increases rapidly,
After it is higher than the atmospheric pressure and the train has passed the measurement point,
The pressure at the measurement point decreases rapidly and becomes lower than the atmospheric pressure. For example, in the case of a tunnel in which a Shinkansen runs, the air pressure in the tunnel is "atmospheric pressure + 0.2 k
g / cm ² ”, and immediately thereafter,“ atmospheric pressure-
It falls to about 0.2 kg / cm ² ". This rapid change in air pressure exerted pressure on each water surface through a reference water tank surface (hereinafter referred to as a reference water surface) and an air pipe opening opened to the atmosphere of the sinking measurement device, and as a result, the water level fluctuated. . That is, when the atmospheric pressure rises, the water surface receives pressure and the water level falls, and when the atmospheric pressure decreases, the pressure applied to the water surface is removed and the water level rises.

In particular, the reference water surface has a large surface area exposed to the atmosphere, and the entire water surface is affected by atmospheric pressure fluctuations when a train passes. Therefore, the reference water surface repeatedly rises and falls every time a train passes. The vibration of the water level of the reference water surface became a wave, and the water level of the measurement pipe was gently vibrated through the communication pipe, so that the accurate settlement amount could not be measured.

In a tunnel where a large amount of trains pass, the next train passes before the vibration of the reference water surface stops, and in the worst case, the vibration of the water surface is superimposed and the vibration of the reference water surface does not stop. In some cases, it was amplified, making it impossible to evaluate the amount of settlement.

[0010] In view of the above problems, the present invention reduces the pressure fluctuation even if it receives a sudden change in the pressure caused by the train passing through the tunnel, and makes it more accurate than the conventional method. It is an object to provide a subsidence measuring device capable of measuring the subsidence.

[0011]

Means for Solving the Problems The present invention is constituted as follows in order to solve the above-mentioned problems. The present invention provides a reference water tank having a constant water level contained in a closed container, one or more measurement pipes, a communication pipe connecting the reference water tank and the measurement pipe below the water surface, and an upper part above the water surface. An air pipe communicating the closed vessel and the measuring pipe, and a sink measuring device for measuring a settling amount at a place where the measuring pipe is installed, by a water level of the measuring pipe, wherein the inside of the closed vessel and It has ventilation means for freely circulating the atmosphere between the outside and the outside, and for moderately reducing the pressure difference between the inside and outside of the closed container by inflow of the air into the closed container or outflow of the atmosphere from the closed container. It has a configuration of a settlement measuring device.

According to the present invention, the reference water tank is housed in an airtight container, and the means for ventilating the airtight container and the outside of the airtight container (hereinafter referred to as "outside world") is only a ventilation means. Limited to.

When the reference water tank is housed in a closed container as in the present invention, if a sudden change in air pressure occurs in the outside world, a pressure difference is generated inside and outside the closed container. In order to eliminate this pressure difference, air movement (inflow or outflow of air) occurs inside and outside of the closed vessel.

However, in the present invention, as described above, the exchange of the atmosphere between the sealed container and the outside world is restricted to only the ventilation means. Therefore, the only way to eliminate this pressure difference is to move the atmosphere through the ventilation means. There is no way.

By the way, since it takes a certain amount of time to complete the movement of the atmosphere through the ventilation means, the structure according to the present invention enables the closed container to be used when a sudden change in air pressure occurs in the outside world. The internal pressure fluctuation is more gradual than the external pressure fluctuation. As a result, the reference water tank housed in the sealed container is not directly affected by sudden external pressure fluctuations, and the vibration of the reference water surface when sudden pressure fluctuations occur in the outside world is suppressed more than conventional methods It is possible to do.

Further, since the atmosphere between the closed container and the outside is always circulated through the ventilation means, the inside of the closed container is kept at the atmospheric pressure when no sudden change in the atmospheric pressure occurs in the outside. In other words, because of the ventilation means, the reference water tank contained in the closed container and the measurement pipe communicated with the reference water tank and the air pipe always exist under the atmospheric pressure.
The accuracy of the settlement measurement is guaranteed.

Here, "gradual relaxation" means that the pressure fluctuation speed inside the sealed container is higher than the fluctuation speed of the pressure fluctuation outside the sealed container, for example, when a sudden pressure change occurs due to the passage of a train or the like. This means that is reduced.

Further, the present invention has the construction of a settlement measuring apparatus according to claim 1, wherein the ventilation means is a small-diameter ventilation hole opened in the closed container.

The present invention is configured as described above, and the ventilation means is a small-diameter ventilation hole provided in a closed container. Thereby, when a pressure difference occurs inside and outside the sealed container due to a sudden pressure change in the outside world, the atmosphere moves only through this small-diameter vent in the closed container, and the sudden pressure change in the outside world is Since the vibrations are transmitted to the reference water surface in a relaxed form, the vibration of the reference water surface can be suppressed more than before.

Further, the present invention has the construction of a settlement measuring apparatus according to claim 1, wherein the ventilation means is a small-diameter ventilation pipe provided in the closed container.

The present invention is constructed as described above, and the ventilation means is a small-diameter ventilation pipe. Thereby, the atmosphere in the ventilation pipe plays the role of resistance, and when a pressure difference occurs inside and outside the closed container due to a sudden pressure change in the outside, the pressure change in the outside is reduced more than the above-mentioned vent. Since the vibrations are transmitted to the reference water surface in a bent form, the vibration of the reference water surface can be further suppressed.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of the settlement measuring apparatus of the present invention, and FIG. 2 is a schematic diagram illustrating the difference between the atmospheric pressure fluctuation in the outside world and the air pressure fluctuation in the closed vessel.

FIG. 1 is a schematic view of a settlement measuring apparatus according to the present invention. The squat measurement device includes a reference water tank 1 in which the level of water contained in a closed container 2 is kept constant, measurement pipes 9 and 10, and a communication pipe connecting the reference water tank 1 and the measurement pipes 9 and 10 below the water surface. 8, an air pipe 12 communicating the closed vessel 2 and the measuring pipes 9 and 10 above the water surface, and a closed vessel 2
And the ventilation pipe 13 provided in the first section.

In the present invention, it is assumed that the entire settlement apparatus (the reference water tank and the measuring pipe) is installed in a place where a sudden change in air pressure occurs, such as a train tunnel.

The reference water tank 1 is housed in a closed container 2. The reference water tank 1 is internally divided into two tanks, and includes a main water tank 4 for obtaining a reference water surface 3 serving as a measurement reference, and a spare water tank 5 for constantly supplying water to the main water tank 4. . The reserve water tank 5 is provided with a water pump 6 and has a structure such that water is always supplied to the main water tank 4 little by little through a supply pipe 7. Since the reference water tank 1 is configured in this way, the main water tank 4 is kept in a state of constantly overflowing, whereby the reference water surface 3
Always maintains a constant water level. Further, the overflowed water flows into the spare water tank 5 again and is reused.

Since the reference tank 1 provides a reference height for measuring the amount of settlement, it is desirable to install the reference tank 1 in a solid place where the height of the ground does not fluctuate. Reference tank 1
A communication pipe 8 is installed in the main water tank 4 below the water surface. The communication pipe 8 is led out of the closed vessel 2 without breaking the tightness of the closed vessel 2, and communicates with the bottoms of the measurement pipes 9 and 10. The sealed container 2 used in the present invention has a robust structure that is not deformed even by a pressure difference between the outside and the inside of the sealed container 2.

The measuring tubes 9 and 10 are installed at an arbitrary place where the amount of settlement is to be evaluated. If the height of the installation place of the measurement pipes 9 and 10 changes, the water level in the measurement pipes changes according to the amount of subsidence of the ground. From the change in the water level of the measuring pipe, it is possible to evaluate the amount of change (uplift, settlement) of the ground relative to the reference water surface.

Although two measuring tubes are used in the present embodiment, the number of the measuring tubes can be freely changed as required for the measurement.

The measuring pipes 9 and 10 are provided with a measure 11 for measuring the water level, so that the water level in the measuring pipes can be easily measured. The means for evaluating the change in the water level is not limited to the measure 11, and for example, a known means such as a water pressure gauge attached to the bottom of the measurement tube can be used.

Further, the measuring tubes 9 and 10 are communicated with the closed container 2 by an air tube 12. The air pipe 12 makes it possible to equalize the air pressure applied to the reference water surface 3 and the water surface inside the measurement pipes 9 and 10, so that it is possible to accurately measure the amount of settlement.

The closed vessel 2 is provided with a ventilation pipe 13 as a ventilation means for keeping the closed vessel 2 at atmospheric pressure and for reducing sudden pressure fluctuations occurring in the outside world. The ventilation pipe 13 is the most significant feature of the present invention, and has a throttling function in terms of hydrodynamics, and acts as a buffer mechanism for a sudden change in atmospheric pressure generated outside the closed vessel 2.

The role of the ventilation pipe 13 will be described with reference to FIG. In FIG. 2, the vertical axis represents the atmospheric pressure (arbitrary unit) with reference to the atmospheric pressure, and the horizontal axis represents time (arbitrary unit). The solid line in FIG. 2 schematically represents the outside air pressure generated when the train passes inside the tunnel. The broken line in FIG. 2 represents the air pressure in the closed container 2 having the ventilation pipe 13 corresponding to the change in the air pressure.

The atmospheric pressure (solid line) in the outside world rapidly increases from the atmospheric pressure (FIG. 2a) as the train passes, and reaches a maximum value (FIG. 2).
After b), the pressure rapidly decreases (FIG. 2C), falls below the atmospheric pressure, increases again after reaching the minimum value (FIG. 2D) (FIG. 2E), and returns to the atmospheric pressure. When such a pressure fluctuation occurs in the outside world, the following changes occur in the closed container 2 having the ventilation pipe 13.

First, a pressure difference between the outside and the inside of the closed container 2 (outside> the inside of the closed container 2) occurs due to the rise in the outside pressure.
In order to eliminate this pressure difference, the air flows into the closed casing 2 from the outside through the ventilation pipe 13. Here the ventilation pipe 13
Is sufficiently small, the ventilation pipe 13 functions as a hydrodynamic throttle, and the amount of air flowing into the sealed container 2 from the outside world per unit time is suppressed. It increases slowly compared to the increase in atmospheric pressure (Fig. 2a ').

The pressure rise start point (FIG. 2z) inside the closed vessel 2 is later than the atmospheric pressure rise start point (y in FIG. 2) because the vent pipe 13 has a certain length. This is because it takes a certain amount of time for the atmosphere to move inside the ventilation pipe 13 and actually increase the air pressure inside the sealed container 2. In addition, since the ventilation pipe 13 has a finite length, a secondary effect of easing the pressure fluctuation inside the sealed container 2 due to the resistance in the pipe when the air passes through the ventilation pipe 13 is produced.

Thereafter, the pressure inside the sealed container 2 gradually increases, and reaches a maximum value (FIG. 2B ') when the pressure inside the sealed container 2 becomes equal to the atmospheric pressure in the outside world. However, as described above, there is a delay time for the air to move through the ventilation pipe 13 to change the air pressure inside the sealed container 2. This is at a point b 'which is slightly delayed from a point x at which the atmospheric pressure and the atmospheric pressure of the closed container 2 become equal.

After the point b ', the air pressure inside the sealed container 2 becomes larger than the outside world, so that the atmosphere flows out from the sealed container 2 to the outside world, and the air pressure inside the sealed container 2 gradually decreases. (FIG. 2 c ′), when the pressure inside the sealed container 2 becomes equal to the atmospheric pressure, the minimum value (FIG. 2 c) is reached.
d '). Thereafter, the air pressure in the sealed container 2 becomes smaller than the outside atmosphere, so that the atmosphere is supplied from the outside to the ventilation pipe 13.
, And the air pressure in the closed container 2 gradually increases (FIG. 2e '), and then returns to the atmospheric pressure.

It should be noted here that the range between the maximum value (FIG. 2b ') and the minimum value (FIG. 2d') of the atmospheric pressure in the sealed container 2 is determined by the fluctuation range of the atmospheric pressure (point in FIG. 2). (difference between b and point d), and that the pressure fluctuation inside the sealed container 2 is gentler than the pressure fluctuation in the outside world.
Is a point. This is the effect of providing the closed container 2 with the ventilation tube 13. By providing the ventilation pipe 13 in the closed vessel 2 as in the present invention, the pressure fluctuation inside the closed vessel 2 is reduced as described above as compared with the atmospheric pressure fluctuation.
The vibration of the internal reference water surface 3 is suppressed more than before, and more accurate measurement of the settlement amount can be performed.

If the opening area of the ventilation pipe 13 is too large,
The effect of buffering sudden pressure fluctuations occurring in the outside world is diminished. In other words, referring to FIG. 2, the pressure fluctuation curve (dotted line) inside the closed container 2 becomes steep and approaches the pressure fluctuation curve (solid line) of the outside world, which is not preferable. Further, if the opening area of the ventilation pipe 13 is too small, the flow of the atmosphere between the outside and the inside of the sealed container 2 is obstructed and the pressure inside the sealed container 2 is maintained at the atmospheric pressure in a situation where no sudden change in the atmospheric pressure occurs in the outside. It is not preferable because it becomes difficult.

The specific numerical value of the opening area of the ventilation pipe 13 required to effectively mitigate the pressure fluctuation in the outside world depends on the volume of the subsidence measuring device to be used, the magnitude of the pressure fluctuation generated in the tunnel, and the like. It is difficult to make a general decision because of the dependence on the ventilation pipe 1
It is desirable to determine the optimum value by a preliminary experiment in which the opening area of No. 3 is variously changed. To give an example of an actually used squat measurement device, when the opening of the ventilation pipe 13 is circular, when the diameter is 0.5 to 2 mm, it is preferable to measure the squat amount which is not affected by the atmospheric pressure fluctuation when passing through the train. Can be implemented.

In the case where a sudden change in atmospheric pressure occurs in the outside world, the longer the ventilation pipe 13 is, the longer the resistance of the atmosphere when the air passes through the ventilation pipe 13 becomes, the more the sealed vessel 2 is closed. It is possible to buffer pressure fluctuations transmitted to the inside.

[0042]

Since the present invention is constructed as described above, the following remarkable effects can be obtained. (1) Since the reference water tank is housed inside the sealed container and the circulation of the atmosphere between the inside of the sealed container and the outside world is limited only to the ventilation means,
Sudden pressure fluctuations occurring in the outside world are mitigated by the ventilation means. This makes it possible to reduce pressure fluctuations applied to the reference water surface inside the sealed container more than the outside world.
Therefore, it becomes possible to suppress the vibration of the reference water surface,
A place where the atmospheric pressure fluctuates greatly (such as inside a train tunnel)
It has become possible to measure the amount of settlement more accurately than before (claim 1). Further, since the inside of the closed container is always kept at the atmospheric pressure through the ventilation means, the accuracy of the measurement of the settlement amount is guaranteed (claim 1).

(2) According to the present invention, since the ventilation means is a small-diameter ventilation hole or a ventilation pipe opened in a closed container, abrupt atmospheric pressure fluctuations in the outside are mitigated and transmitted to the reference water surface.
Since the vibration of the reference water surface is suppressed more than before, it is possible to measure the amount of settlement more accurately than in the conventional method even in a place where the atmospheric pressure fluctuates greatly (claims 2 and 3).

[Brief description of the drawings]

FIG. 1 is a schematic view of a submerged sinking type according to the present invention.

FIG. 2 is a schematic diagram illustrating a difference between the atmospheric pressure fluctuation in the outside world and the air pressure fluctuation in a closed container.

FIG. 3 shows a schematic view of a conventional settlement measurement device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reference water tank 2 Closed container 3 Reference water surface 4 Main water tank 5 Spare water tank 6 Pumping pump 7 Supply pipe 8 Communication pipe 9,10 Measurement pipe 11 Measure 12 Air pipe 13 Ventilation pipe

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takahiro Kondo 1-25-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo Inside Taisei Construction Co., Ltd. (72) Inventor Hiromichi Miyazaki 1-25-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo Taisei Corporation F term (reference) 2D046 DA23 DA25 2F076 BA01 BB09 BE01

Claims (3)

[Claims] 1. A reference water tank having a constant water level contained in an airtight container, at least one measurement pipe, a communication pipe connecting the reference water tank and the measurement pipe below the water surface, An air pipe communicating with the closed vessel and the measuring pipe at an upper part, and a sinking measuring device for measuring a settling amount of a place where the measuring pipe is installed by a water level of the measuring pipe, wherein the inside of the closed vessel is And a ventilation means for gently mitigating the pressure difference between the inside and outside of the closed vessel by inflow of air into or out of air from the closed vessel. A subsidence measuring device comprising: 2. The settlement measuring apparatus according to claim 1, wherein the ventilation means is a small-diameter ventilation hole opened in the closed container. 3. The settlement measuring apparatus according to claim 1, wherein the ventilation means is a small-diameter ventilation pipe provided in the closed container.