JPH06323851A - Method and equipment for measuring depth of tunnel and bubble removing method therefor - Google Patents

Abstract

PURPOSE:To allow highly accurate measurement by disposing a reference pressure sensor in the vicinity of tunnel inlet within a pit thereby eliminating the influence of fluctuation in the specific gravity of a low viscosity working liquid caused by temperature difference. CONSTITUTION:A head pressure sensor 5 advancing through a tunnel 3 is coupled with an oil tank 7 through a hose 6. A low viscosity working liquid, e.g. silicon oil 8, contained in a tank 7 is filled in the hose 6 and the pressure, at the tip thereof, is detected by means of the sensor 5. At the same time, a reference pressure sensor 9 disposed on the bottom of a pit measures the oil pressure of the hose 6 at the inlet of tunnel 3 thus determining the difference DELTAP between the reference pressure Pa and the pressure Pb at the tip of hose. The depth of the sensor 5 can be determined according to a formula; DELTAP=¦Pb-Pa¦=rho.g(¦Ha-Hb¦) (rho: specific gravity of oil, g: gravitational acceleration). Consequently, the depth of the sensor 5, and thereby the depth of a leading body 4a, can be measured continuously as an excavator advances. Since the hose 6 and the oil 8 are set under the ground between the sensors 9, 5, the temperature scarcely changes and thereby the specific gravity rho scarcely fluctuates.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the depth of a tunnel for burying communication cables, electric wires, water and sewage, gas pipes, etc. excavated under a road, and more particularly, a method for excavating a road without excavating it. TECHNICAL FIELD The present invention relates to a depth measuring method which is effective when measuring the depth of the head position of a machine, and a depth measuring device, and a defoaming method in this device in a method of digging a tunnel with a machine.

[0002]

2. Description of the Related Art Conventionally, when a pipeline such as a communication cable, an electric wire, a water supply and a sewer, a gas pipe is installed in the ground, a road is conventionally excavated to form a deep groove and a buried pipe is embedded in the groove. Has been adopted. However, such a road excavation method interrupts traffic and digs deep grooves with a machine such as an excavator, which causes noise and vibration, and also requires soil disposal, which greatly affects the living environment. Exert.

For this reason, recently, a method has been adopted in which an excavator is installed in a shaft formed in the ground, and a tunnel is horizontally excavated from the shaft by the excavator. In this type of excavator, a hydraulic jack pushes the leading conductor a predetermined stroke in the ground, and after the leading conductor moves forward, it pushes the subsequent connecting pipe toward the leading conductor side, propelling the so-called underground into a tunnel. Is a method of digging. The tunnel construction method using such an excavator is capable of excavating a tunnel having a diameter of 30 to 40 cm to a length of about 250 m, and further, by controlling the traveling direction of the front conductor by controlling the hydraulic jack, the radius of curvature is about 150 m. It is also possible to dig a bent tunnel.

By the way, in such a tunnel excavation method using an excavator, it is necessary to monitor whether or not the excavator is advancing in a predetermined direction. That is, since the front conductor cannot be visually recognized from the ground, it is necessary to always check the horizontal direction and the vertical direction (depth) of the front conductor in the ground to measure whether or not there is any deviation in the tunnel excavation direction.

In the conventional case, a method of irradiating a laser beam from the entrance of a tunnel and monitoring the excavation direction while searching for the position of the leading conductor by this laser beam has been studied. The laser beam does not reach when the is bent, and the reliable measurement length is up to 1
Since it is around 00m, you cannot see beyond it, and the above 250m
It is not suitable for measuring the leading conductor of an excavator that can excavate up to and can also construct a bent tunnel.

For this reason, a magnetic field detecting method has been developed as a method for measuring the horizontal position of the leading conductor. This is because the transmitter coil is attached to the conductor of the excavator, a current is applied to the transmitter coil to generate a magnetic field in the ground, and the strength of this magnetic force is detected by the receiver coil installed on the ground. This is a method of measuring the position.
According to this method, even if the depth of the conductor is about 3 m, the horizontal position can be detected with high accuracy and the horizontal measurement error is ± 1 to 2 cm, which is an extremely effective means. It is known that

On the other hand, in order to know the depth of the leading conductor, a pressure measuring method utilizing the principle of a communicating tube (Pitot tube) is used. This method will be described with reference to FIGS. 5 and 6. In FIG. 5, 1 is the ground, 2 is a vertical shaft, 3 is a tunnel excavated by the excavator 4, 4 a is a front conductor of the excavator 4, and 4 b is a connecting pipe subsequent to the excavator 4.

Reference numeral 5 denotes a pressure detector for measuring the depth of the tip attached to the tip conductor 4a of the excavator 4, that is, a tip pressure sensor. The tip pressure sensor 5 is made of silicone oil by a flexible hose 6. It communicates with the tank 7. The oil tank 7 is installed on the ground, and stores a low-viscosity hydraulic fluid such as silicone oil 8. The silicone oil 8 is filled in the hose 6 connected to the oil tank 7. The hose 6 is guided through the vertical shaft 2 and the connecting pipe 4b of the machine 4 and is connected to the tip pressure sensor 5. There is. Tip pressure sensor 5
Although not shown in detail, is composed of a diaphragm that is bent and deformed by the pressure of the silicone oil 8 and a strain gauge attached to the diaphragm. When the diaphragm is bent by the pressure of the silicone oil 8, the strain gauge is The pressure of the silicone oil 8 can be taken out to the depth indicator 10 as an electric signal by bending and changing the electric resistance of the strain gauge.

Reference numeral 9 is a reference pressure sensor, which detects the pressure of the silicone oil 8 on the oil tank 7 side, that is, the reference pressure, to compensate the atmospheric pressure. This reference pressure sensor 9 may also use the above diaphragm and strain gauge.

In such a depth measuring system,
Each time the tip conductor 4a of the excavator 4 advances in the ground, the tip pressure sensor 5 also advances, and the hose 6 is sequentially connected and extended in accordance with this advance.

In such a depth measuring system, the atmospheric pressure is P ₀ , the pressure applied to the reference pressure sensor 9 is P _a , the specific gravity of the silicone oil 8 in the oil tank 7 and the hose 6 of the shaft 2 is ρ, and gravity. Is g and the height difference from the liquid surface of the oil tank 7 to the reference pressure sensor 9 is H ₀ , the reference pressure P _a detected by the reference pressure sensor 9 is P _a = P ₀ + ρ · g · H ₀ (1) in addition, the height difference from the reference pressure sensor 9 to promote opening which is open at the bottom of the shafts 2 H _a, the difference in height H _b from the tip pressure sensor 5 to the propulsion port of the shafts 2, shield machine 3 If the specific gravity of the silicone oil 8 inside is ρ, the tip pressure sensor 5
Oil pressure P _b which acts on the detected pressure (reference pressure) of _{P b = P 0 + ρ ·} g · H 0 + ρ · g · H a -ρ · g · H b (2) These reference pressure sensors 9 P _a
Difference ΔP between the pressure measured by the tip pressure sensor 5 and P _b
ΔP = P _b −P _a = ρ · g (H _a −H _b ) (3) That is, assuming that the specific gravity ρ of the silicone oil 8 and the acceleration g of gravity are constant, the pressure difference ΔP is the reference pressure. It is expressed by a function of the difference in height between the sensor 9 and the tip pressure sensor 5 (H _a -H _b). If the position of the reference pressure sensor 9 is not moved during the tunnel excavation work, the pressure difference ΔP will eventually change according to the depth of the tip pressure sensor 5, and if this pressure difference is measured, the tip pressure will be changed. The depth position H of the sensor 5 can be measured, and this depth H is displayed on the depth display 10.

The reference pressure sensor 9 is used to correct the atmospheric pressure, and when the atmospheric pressure changes, the pressure detected by the tip pressure sensor 5 changes, causing a measurement error and varying accuracy. Therefore, the reference pressure sensor 9
Thus, the pressure at hand is measured, and the measured pressure of the tip pressure sensor 5 is compared to eliminate the influence of the atmospheric pressure fluctuation.

By the way, silicone oil has a property that the value of specific gravity varies depending on the temperature difference. For example, in the case of Toshiba Silicone TFS-10, the specific gravity at 25 ° C. is 9.35 × 1.
It is 0 ² kg · m ^-3 and the specific gravity at 15 ° C is 9.249 × 1.
0 ² kg · m ^-3, and the the temperature is different 1 ℃ specific gravity 1.0
A difference of 8 × 10 ⁻³ kg · m ⁻³ is produced.

When such a specific gravity difference occurs, the measurement accuracy varies, and a measurement error of about 10 to 20 cm occurs at a depth of 7 m.

[0015]

Despite these conditions, in the conventional case, the oil tank 7 and the reference pressure sensor 9 are installed on the ground, and the hose 6 is installed from the vertical shaft 2 to the excavator 4. It was inserted through the inside and led to the tip pressure sensor 5. Therefore, the silicone oil 8 is affected by the outside air temperature in the area from the shaft 2 to the ground, and a temperature difference is generated. In other words, the summer daytime temperature exceeds 30 ℃, and the surface temperature is 40 ℃.
Reach near In the early mornings and nights of winter, the temperature drops below freezing and the surface temperature also drops. On the other hand, the underground temperature does not change so much, and the greater the depth, the less affected by the outside temperature. Therefore, when the oil tank 7 and the reference pressure sensor 9 are installed on the ground, the specific gravity of the silicone oil 8 in the hose 6 changes due to the influence of the outside temperature, the measured pressure varies, and the depth of the There is a problem that the measurement accuracy decreases.

On the other hand, in this type of depth measuring device, when the air 20 is mixed in the silicone oil 8 and / or the hose 6, since the air is compressible, the pressure fluctuates according to the mixed amount. . For example, in FIG. 6, when an air pool having the mixing length s is generated in the rising hose 6 connected to the tip pressure sensor 5 side, the compressed air pushes the silicone oil 8 by the length s, and thus the measured pressure is higher than the actual pressure. Measure the value. Therefore, in such a case, there is a problem that the tip pressure sensor 5 measures a deeper position than it actually is.

The present invention has been made in view of the above circumstances. A first object of the present invention is to avoid the influence of the variation in specific gravity due to the temperature difference of a low-viscosity hydraulic fluid such as silicone oil, and to perform measurement. An object of the present invention is to provide a tunnel depth measuring method and a depth measuring device that can improve accuracy.

A second object of the present invention is to provide a defoaming method in a tunnel depth measuring apparatus which can prevent air bubbles from remaining in the hose and improve the measurement accuracy. It is a thing.

[0019]

In order to achieve the above-mentioned object, the method for measuring the depth of a tunnel of the present invention is such that a tip pressure sensor is propelled in a tunnel extending laterally from a shaft.
This tip pressure sensor and the tank installed outside the tunnel are connected by a hose, the low-viscosity hydraulic fluid contained in the tank is filled into the hose, and the tip pressure sensor detects the pressure at the tip of the hose, The pressure of the working fluid outside the tunnel is measured by a reference pressure sensor, and by the pressure difference between the tip pressure and the reference pressure,
In the method of measuring the depth of the tip pressure sensor in the ground, the reference pressure sensor is arranged in the vicinity of the tunnel entrance in the shaft.

The tunnel depth measuring device of the present invention has a tip pressure sensor and a tank containing a low-viscosity hydraulic fluid, and the tank and the tip pressure sensor are connected by a hose filled with the hydraulic fluid. A reference pressure sensor for measuring the reference pressure of the hydraulic fluid is provided in the middle of the hose.

Further, in the defoaming method of the present invention, the inside of a tank containing a low-viscosity working fluid is evacuated by a vacuum pump to remove air bubbles mixed in the working fluid, and a hose is attached to this tank. After being connected, the hose is evacuated by a vacuum pump to eliminate air in the hose, and then the working fluid in the tank is introduced into the hose.

[0022]

According to the tunnel depth measuring method and the depth measuring apparatus of the present invention, since the reference pressure sensor is arranged near the tunnel entrance in the shaft to measure the pressure, the area from the reference pressure sensor to the tip pressure sensor is Since it is underground, it is unlikely to be affected by changes in the outside air temperature, and therefore measurement errors due to changes in specific gravity can be eliminated, and depth can be measured with high accuracy.

Further, in the defoaming method according to the present invention, since air bubbles mixed in the low-viscosity hydraulic fluid and air in the hose are removed by the vacuum pump, no air bubbles remain in the hose, and the measurement is performed. Pressure variations are prevented and highly accurate measurement is possible.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the first embodiment shown in FIGS.

The embodiment shown in FIG. 1 may be similar to the prior art example shown in FIG. 4 in the basic structure. The same components are designated by the same reference numerals, 1 is the ground, 2 is a vertical shaft, and 3 is an excavation. A tunnel excavated by the machine 4, 4a is a front conductor of the machine 4, 4b is a connecting pipe subsequent to the machine 4, 5 is a front conductor 4 of the machine 4
Depth measuring tip pressure sensor attached to a, 6 is a flexible hose, 7 is a silicone oil tank, 8 is a low viscosity hydraulic fluid such as silicone oil, 9 is a reference pressure sensor for atmospheric pressure compensation, and 10 is It is a depth indicator.

In this embodiment, the difference from the case of FIG. 4 is that a reference pressure sensor 9 is provided at the bottom of the shaft 2 so that this reference pressure sensor 9 measures the oil pressure at the entrance of the tunnel 3 in the hose 6. It has become.

Even in such a case, the difference ΔP between the reference pressure P _a measured by the reference pressure sensor 9 and the tip pressure P _b measured by the tip pressure sensor 5 is ΔP = | P _b −P _{Since a} | = ρ · g (| H _a −H _b |), the depth of the tip pressure sensor 5 can be measured from this pressure difference ΔP. Therefore, the depth of the tip pressure sensor 5, that is, the depth of the tip conductor 4a, that is, the depth of the tip of the tunnel 3 can be continuously measured according to the advance of the excavator 4.

Moreover, the hose 6 from the reference pressure sensor 9 to the tip pressure sensor 5 and the silicone oil 8
Since it is in the ground, its temperature hardly changes, and therefore the specific gravity ρ does not vary. Therefore, the variation in the measured pressure value can be eliminated, and the measurement accuracy is improved.

If the measured values of the tip pressure sensor 5 and the reference pressure sensor 9 and the measured depth value of the reference pressure sensor 9 are measured in advance, and the specific gravity ρ of the silicone oil 8 is obtained from these values, Since the specific gravity can be corrected in advance by the temperature in the ground, highly accurate depth measurement can be performed regardless of the temperature in the ground.

Further, since the two tip pressure sensors 5 and the reference pressure sensor 9 both communicate with the oil tank 7, when the oil tank 7 is open to the atmosphere,
Both sensors 5 and 9 can detect the atmospheric pressure at the same time, so that the variation of the atmospheric pressure is automatically corrected and is not affected by the variation of the atmospheric pressure.

From the above, when using Toshiba Silicone TFS-10, for example, the error when measuring a depth of 5 m could be suppressed to 7 mm or less.

2 and 3 illustrate a method of defoaming so that air does not remain in the silicone oil 8 in the hose 6 and the oil tank 7.

In FIG. 2A, after the silicone oil 8 is injected into the oil tank 7, the silicone oil 8 is injected.
Oil tank 7 to remove air bubbles mixed in
The upper space of is connected to the vacuum pump 30, and the vacuum pump 30 is operated with the cock 31 on the hose 6 side closed. Then, the air bubbles mixed in the silicone oil 8 are forcibly lifted and removed through the vacuum pump 30.

Next, as shown in FIG. 2B, the vacuum pump 30 is connected to the hose 6 via a cock 32, the cock 32 is opened, and the cock 31 on the tank side is closed. To drive. Then, the air in the hose 6 is removed, and the hose 6 becomes negative pressure. When the cock 31 is opened while operating the vacuum pump 30 in this state, the silicone oil 8 in the tank 7 is introduced into the hose 6 and filled in the hose 6. As a result, no air remains in the hose 6.

When the hose 6 is replenished by the forward movement of the excavator 4, as shown in FIG. 3A, the vacuum pump 30 is connected to the hose 6 and the cock 31 on the tank 7 side is closed. The cock 32 on the pump 30 side is opened to operate the vacuum pump 30, and the silicone oil 8 in the hose 6 is returned to the tank 7 through the return hose 33.

When the silicone oil 8 in the hose 6 is exhausted, a new hose 6a is connected to the hose 6 as shown in FIG. 3B, and a vacuum pump is connected to the new hose 6a via a cock 34. Connect 30. Pump 3 above
The vacuum pump 30 is operated with the cock 34 on the 0 side opened and the cock 31 on the tank 7 side closed. Then, the air in the hoses 6 and 6a is removed, and the inside of these becomes negative pressure. While operating the vacuum pump 30 in this state, the cock 31
When opened, the silicone oil 8 in the tank 7
And 6a and fill these hoses 6 and 6a. As a result, the silicone oil 8 can be filled into the hoses 6 and 6a without leaving air.

Therefore, according to such a defoaming method,
Since no bubbles remain in the silicone oil 8 in the hose 6 or the tank 7 and no air is trapped in the hose 6, a pressure error does not occur and the depth measurement accuracy is improved.

The present invention is not limited to the above embodiment.

That is, in the embodiment shown in FIG. 1, the case where the oil tank 7 is installed on the ground 1 has been described, but as in the other embodiment shown in FIG. It may be installed at the bottom of No. 2. In this case, when the position of the tip pressure sensor 5 is higher than the liquid level of the oil tank 7, the silicone oil 8 in the hose 6 may flow backward, so the oil tank 7 is sealed.
The pressure in the oil tank 7 may be set higher than the atmospheric pressure, that is, the reference pressure may be set high.

In the above embodiment, an example in which silicone oil is used as the hydraulic fluid for transmitting pressure has been described.
The present invention is not limited to this, and the hydraulic fluid for pressure transmission can be implemented as long as it has low viscosity and its specific gravity changes due to temperature change.

In the above embodiment, the case where the tip pressure sensor 5 is attached to the tip conductor 4a of the machine 4 and the position of the tip conductor 4a is searched has been described. The position of the tunnel 3 is detected, and the tip pressure sensor 5 is not limited to being attached to the tip conductor 4a of the excavator 4. For example, when it is desired to know the route of an existing tunnel, the depth of this tunnel can be continuously measured by attaching the tip pressure sensor 5 directly inside the existing tunnel or by attaching it to a separate conductor. Therefore, the present invention can be applied to such an existing tunnel and can be implemented even in a bent tunnel.

[0042]

As described above, according to the tunnel depth measuring method and depth measuring apparatus of the present invention, the reference pressure sensor is arranged near the tunnel entrance in the shaft to measure the pressure. The temperature difference with the pressure sensor is small, and the change in the specific gravity of the low-viscosity hydraulic fluid between them is small. Therefore, the change in the specific gravity due to the change in the outside air temperature is small, so that the pressure variation is small, and the depth measurement accuracy can be improved.

Further, according to the defoaming method of the present invention, the bubbles mixed in the low-viscosity hydraulic fluid and the air in the hose are removed by the vacuum pump, so that the bubbles do not remain in the hose and the measurement is performed. Pressure variations are prevented and highly accurate measurement is possible.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a depth measuring apparatus showing a first embodiment of the present invention.

2A and 2B are views for explaining a method for defoaming silicone oil of the same example.

3A and 3B are views for explaining a method for defoaming silicone oil when connecting the hoses of the same embodiment.

FIG. 4 is a diagram showing a schematic configuration of a depth measuring apparatus showing a second embodiment of the present invention.

FIG. 5 is a diagram showing a schematic configuration of a conventional depth measuring device.

FIG. 6 is a diagram showing a schematic configuration when air is mixed in the depth measuring device.

[Explanation of symbols]

 1 Ground 2 Vertical shaft 3 Tunnel 4 Machine 4a Leading conductor 4b Connecting pipe 5 Tip pressure sensor 6 Hose 7 Oil tank 8 Silicone oil 9 Reference pressure sensor 10 Depth indicator

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Kasai 5-8 Akihabara, Taito-ku, Tokyo Airec Giken Co., Ltd.

Claims (4)

[Claims] 1. A tip pressure sensor is propelled in a tunnel extending laterally from a vertical shaft, the tip pressure sensor and a tank installed outside the tunnel are connected by a hose, and the low-viscosity hydraulic fluid stored in the tank is Fill the hose,
The pressure at the tip of the hose is detected by the tip pressure sensor, the pressure of the working fluid outside the tunnel is measured by a reference pressure sensor, and the tip pressure sensor is determined by the difference between the tip pressure and the reference pressure. In the method of measuring the depth in the ground, the reference pressure sensor is arranged in the vicinity of the tunnel entrance in the shaft, the depth measuring method of the tunnel. 2. The tip pressure sensor is attached to a front conductor of an excavator for advancing a tunnel, and the depth of the front conductor is measured to measure the depth of the tunnel. How to measure the depth of a tunnel. 3. A tip pressure sensor and a tank containing a low-viscosity hydraulic fluid are provided. The tank and the tip pressure sensor are connected by a hose filled with the hydraulic fluid, and a hydraulic fluid is provided in the middle of the hose. A depth measuring device for a tunnel, comprising a reference pressure sensor for measuring a reference pressure. 4. A vacuum pump is used to evacuate the inside of a tank containing a low-viscosity hydraulic fluid to remove air bubbles mixed in the hydraulic fluid, and a hose is connected to this tank. A method for defoaming in a depth measuring device of a tunnel, characterized in that the working fluid in the tank is introduced into the hose after the air in the hose is removed by vacuuming.