JPH0696942B2 - Monitoring device in muddy water shield chamber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a monitoring device in a muddy water type shield chamber, and in particular, to muddy water supplied into the chamber using a water injection pipe, and a drain pipe to provide the chamber. The present invention relates to a device for measuring the flow velocity and density of muddy water discharged from a device and monitoring the condition inside the shield chamber from the measured values.

[Prior Art] As is well known, the muddy water type shield construction method is widely used as one of the sealed shield construction methods.

In this muddy water shield construction method, muddy water and earth and sand are mixed in a chamber to form a slurry and the slurry is discharged. Therefore, accurate measurement of the mud density in the shielded chamber and calculation of the amount of discharged mud, and consequently the amount of dry sand, are important for good excavation control.

In order to perform such density measurement, conventionally, there has been known a monitoring device in which a differential pressure densitometer is provided in a drain pipe to measure the density of mud water which is slurried from a chamber and discharged.

[Problems to be Solved by the Invention] However, since the differential pressure densitometer obtains the muddy water density from the difference in hydraulic pressure, if muddy water is mixed with gravel, the muddy water density, and thus the dry water taken into the chamber, will be reduced. There is a problem in that it is impossible to accurately measure the amount of sand and to accurately grasp the filled state of sediment in the chamber.

Further, the differential pressure densitometer cannot follow a sudden change in density of muddy water, which makes it difficult to use as a sensor for real-time measurement.

Furthermore, the differential pressure densitometer simply measures the density of the muddy water, and when measuring the muddy water flow rate, etc., it is necessary to provide a flow rate sensor or the like separately from the muddy water, which makes the entire apparatus complicated and expensive. There was a problem that became.

The present invention has been made in view of such conventional problems, and an object thereof is muddy water injected into a shield chamber using a water injection pipe, and muddy water discharged from the shield chamber using a drainage pipe. It is an object of the present invention to provide a monitoring device in a muddy water type shield chamber having a simple structure capable of accurately measuring the flow velocity and the muddy water density in real time.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a water injection pipe for injecting water into a muddy water shield chamber, and a drainage pipe for discharging slurry that is taken into the muddy water shield chamber and slurried. In a muddy water shield machine, including: and at least one of a pair of ultrasonic waves that are arranged to face at least one of the water injection pipe and the drain pipe so as to intersect at a predetermined angle with respect to the flow direction of the muddy water flowing in the pipe It is characterized by including a transmitter / receiver and an operation unit for calculating the flow velocity and density of the muddy water flowing in the pipe based on the ultrasonic wave transmission / reception timing and the ultrasonic attenuation amount of the pair of ultrasonic wave transmitters / receivers.

[Operation] In the present invention, at least a pair of ultrasonic transceivers is provided on at least one of the water injection pipe and the drain pipe.
The pipes are arranged so as to intersect with the flow direction of the muddy water flowing in the pipe at a predetermined angle.

At this time, the ultrasonic wave propagation velocity between the pair of ultrasonic wave transmitters / receivers changes in accordance with the flow velocity. Therefore, the flow velocity of the muddy water flowing in the pipe can be obtained by measuring the ultrasonic wave propagation time between the pair of ultrasonic wave transmitters / receivers.

Further, when ultrasonic waves are transmitted and received in the muddy water, the ultrasonic waves are attenuated according to the density of the muddy water. Therefore, by obtaining the attenuation amount of the ultrasonic waves transmitted and received between the pair of ultrasonic transceivers, the density of the muddy water flowing in the pipe can be obtained in real time.

In this way, according to the monitoring device of the present invention, the flow velocity and density of the muddy water flowing in at least one of the water injection pipe and the drainage pipe can be accurately measured in real time, so that the soil filled in the shield chamber can be filled. It becomes possible to accurately grasp the changes in the situation in real time and manage the excavation.

In particular, in the recent shield construction method, a computer performs centralized control of the shield machine. Therefore, the monitoring device according to the present invention, which can accurately grasp the density and flow velocity of muddy water in real time, is extremely suitable as a sensor part of a computer.

Furthermore, according to the present invention, using a pair of ultrasonic transceivers,
The flow velocity and density of mud can be measured simultaneously,
The configuration is simpler and less expensive than the conventional monitoring device that measures the density and the flow velocity using separate sensors.

[Embodiment] Next, a preferred embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a preferred example of a muddy water shield machine to which the present invention is applied.

The muddy water shield machine of the embodiment is provided with a partition wall 12 at the front part of the shield 10, and on the face 22 side of this partition wall 12, inside the tunnel premises.
A sealed space isolated from 24 is formed as a shield chamber 14. The inside of this shield chamber 14 is a water injection pipe.
It is filled with 100 muddy water supplied from 16.

The excavation of the cutting face 22 is performed by the rotary cutter 20 that is rotationally driven by a drive device (not shown), and the scraped earth and sand is taken into the shield chamber 14. The earth and sand taken in is agitated with the muddy water in the chamber 14 and discharged from the drain pipe 18 as muddy water slurried.

At this time, the stability of the face 22 is controlled by the concentration and pressure of the muddy water in the shield chamber 14.

In this embodiment, the water injection pipe 16 is provided with an ultrasonic transmitting / receiving device 30a, and the drain pipe 18 is also provided with an ultrasonic transmitting / receiving device 30b. Each of these ultrasonic transceivers 30
It is preferable to provide a and 30b at positions close to the shield chamber 14 in order to accurately grasp the state inside the chamber 14.

FIG. 2 shows a specific configuration of the ultrasonic transmitter / receivers 30a and 30b. Each of the ultrasonic transmitter / receiver devices 30a,
Since the structure of 30b is the same, the structure and operation of the ultrasonic transmitting / receiving device 30b provided in the drainage pipe 18 will be described here as an example.

The ultrasonic transmitter / receiver 30 of the embodiment has a pair of ultrasonic transmitter / receivers 32, 34 arranged on the side wall of the drain pipe 18 so as to face each other at a predetermined angle θ with respect to the flow direction of the muddy water 100 flowing in the pipe. .

A first feature of the present invention is that the pair of ultrasonic transceivers 32, 3
4 is used to measure the flow velocity V of the muddy water 100 flowing in the pipe 18 in real time.

In this, the propagation velocity C of the ultrasonic wave in the stationary liquid
Is a constant value when the type, temperature, and pressure of the liquid are fixed, but when the liquid flows, it changes according to the direction and flow velocity of the flow. For example, if the flow direction and the ultrasonic wave propagation direction are forward, the ultrasonic wave propagation speed increases by the flow velocity, and if the flow direction is opposite, the ultrasonic wave propagation velocity decreases by the flow velocity.

Therefore, ultrasonic pulses are repeatedly transmitted and received alternately from the pair of ultrasonic transmitters / receivers 32, 34, at this time, the propagation time in the forward direction is t ₁ with respect to the flow of the muddy water 100, and the propagation time in the reverse direction is
When the relationship with the flow velocity V of the muddy water 100 is calculated with t ₂ , the relationship shown by the following equation is obtained.

From equations (1) and (2) However, V = Velocity (m / S) L = Distance between transmitter and receiver (m) θ = Angle between ultrasonic wave propagation axis and center axis of tube C = Propagation speed of ultrasonic wave in stationary mud (m / S) ) As can be seen from the equation (3), the difference of the reciprocal of the propagation time and
The relationship with the flow velocity is linearly proportional, its linearity is very good, and by obtaining the reciprocal difference, the term of propagation velocity C in stationary mud is eliminated, so the type of mud, temperature, pressure The flow velocity V can be measured independently of.

In the present embodiment, such flow velocity measurement is performed at 20 times per second.
It is repeatedly performed at the speed of one time, and the calculation is performed in units of 0.01 m / s using the circuit of FIG. 6 described later, so the response speed and flow velocity resolution are extremely excellent, and there is no drift. .

In the apparatus of the embodiment, the flow rate Q of the muddy water 100 flowing in the drainage pipe 18 can be obtained based on the flow velocity V of the muddy water 100 thus obtained. At this time, the flow rate Q is 18
The cross-sectional area S is multiplied by the cross-sectional average flow velocity V of the ultrasonic wave, and the flow velocity V measured using the pair of ultrasonic transceivers 32 and 34.
Is the line average flow velocity of the propagation axis (measurement line) of the ultrasonic waves, and it is necessary to convert this to the cross-section average flow velocity. This conversion is given by the following equation using the Plantile velocity distribution equation.

However, = cross-section average flow velocity (m / S) V = line-average flow velocity measured by ultrasonic flowmeter (m / S)
S) Re = Reynolds number Then, the flow rate Q of the muddy water 100 is obtained by the following equation using this cross-sectional average flow velocity.

Q = × S (5) As described above, according to the present invention, the flow velocity V and the flow rate Q of the muddy water 100 flowing in the pipe 18 can be measured in real time.

The second feature of the present invention is that the muddy water 100 flowing in the pipe 18 is formed by using a pair of ultrasonic transmitters / receivers 32, 34 arranged to face each other.
It is to measure the density ρ of the real time.

That is, when ultrasonic waves are transmitted / received between the pair of ultrasonic wave transmitters / receivers 32, 34, the transmitted ultrasonic wave signals are attenuated by scattering and viscosity at the particle interface of the muddy water 100 and internal friction of the particles.

FIG. 5 (A) shows a rectangular pulse of ultrasonic waves transmitted from the ultrasonic transmitter / receiver 32 to the muddy water 100, and FIG. 5 (B).
In the figure, the reception waveform of the ultrasonic wave received by the ultrasonic transmitter / receiver 34 is shown. As shown in the figure, it will be understood that the ultrasonic wave transmitted to the muddy water 100 is received after being attenuated in the muddy water.

At this time, since the density ρ of the muddy water 100 and the attenuation amount of the ultrasonic waves have a predetermined correspondence relationship, the density ρ of the muddy water 100 can be obtained by measuring the attenuation amount of the received ultrasonic waves.

3 and 4 show measured data of the concentration of solid matter contained in the muddy water and the attenuation rate of ultrasonic waves passing through the muddy water. FIG. 3 shows the data when kaolin is mixed in the muddy water, and FIG. 4 is the data when lime and gypsum are mixed in the muddy water.

As is clear from these measurement data, it is understood that the attenuation of ultrasonic waves has a proportional relationship with the solid content concentration in mud water. Therefore, by transmitting and receiving ultrasonic waves in the muddy water 100 as shown in FIG. 2, the density ρ of the muddy water 100 (volume concentration of the amount of dry sand contained in the muddy water 100 is calculated based on the amount of attenuation of the received ultrasonic waves. ) Can be measured in real time.
At this time, the mud concentration can be measured accurately without being affected by the color, pH, conductivity, etc. of the muddy water, or even if it contains heterogeneous suspended particles such as solid or emulsified particles. It becomes possible.

FIG. 6 shows a preferred example of the circuit configuration of this embodiment. The apparatus of the embodiment, the pair of ultrasonic transceiver 3
An oscillator driving circuit 40 for driving the 2, 34, a memory 42 in which the correlation between the density of the muddy water 100 and the ultrasonic attenuation amount is stored in advance as table data, and an arithmetic circuit for calculating the flow velocity V and the density of the muddy water 100. 44 and.

These oscillator drive circuit 40, memory 42 and arithmetic circuit 44
Is an ultrasonic transmitter / receiver 30a provided in the water injection pipe 16.
One set is provided for each of the ultrasonic transmitting / receiving devices 30b provided in the drainage pipe 18, and the flow velocity V and the density ρ of the muddy water 100 flowing in each of the pipes 16 and 18 are formed so as to be detected in real time. ing.

In this, when the measurement command is input from the outside, the vibrator drive circuit 40 performs an ultrasonic wave transmission / reception operation from one transceiver 32 to the other transceiver 34 and another transceiver 34.
And the ultrasonic transmission / reception operation from one transceiver 32 to the other transceiver 32 are alternately repeated. At this time, the transmitted ultrasonic wave is the fifth ultrasonic wave.
A rectangular pulse as shown in FIG.

As a result, this ultrasonic pulse is attenuated in the muddy water 100 according to its density and is received as an ultrasonic wave having a waveform as shown in FIG. 5 (B).

The memory 42 stores a table of the correlation between the density of the muddy water 100 and the ultrasonic attenuation amount.

Then, the arithmetic circuit 44, based on the input / output signals to the ultrasonic transmitters / receivers 32, 34, ultrasonic waves in a direction opposite to the ultrasonic wave propagation time t ₁ from one transmitter / receiver 32 to the other transmitter / receiver 34. Propagation time t ₂ is obtained, and each propagation time t ₁ , t thus obtained
By substituting ₂ into the third equation, the flow velocity V of the muddy water 100 is calculated and output.

Further, if necessary, the operation of the fourth equation is performed to
The flow rate Q of the muddy water 100 is calculated and output based on the equation.

Further, the arithmetic circuit 44 includes the pair of ultrasonic transceivers.
The density ρ of the muddy water 100 is calculated and output by measuring the attenuation amount of ultrasonic waves transmitted and received between 32 and 34 and comparing the attenuation amount with the table data stored in the memory 42.

Thus, according to the present invention, the flow velocity V, the flow rate Q and the density ρ of the muddy water 100 flowing through the water injection pipe 16 and the drainage pipe 18 are
Can be obtained in real time and accurately.

Particularly, in the present embodiment, by measuring the flow rate and density ρ of the muddy water 100 supplied from the water injection pipe 16 to the chamber 14, and by measuring the flow rate Q and the density ρ of the muddy water 100 discharged from the drainage pipe 18, Shield chamber 14
The amount of earth and sand newly taken in and the amount of earth and sand discharged from the shield chamber 14 can be accurately measured. Moreover, it is possible to accurately measure the filled sediment density in the chamber 14 and other sediment filled states based on the density ρ of the muddy water 100 discharged from the drainage pipe 18.

Therefore, the measurement data of the mud flowing in the water injection pipe 16,
By inputting the measurement data of the muddy water flowing in the drainage pipe 18 to the computer for centralized control of the shield machine in real time, the computer accurately grasps the earth and sand filling state in the chamber 14, and the excavation speed of the shield machine and Controlling the amount of sediment taken into the chamber 14, water injection pipe
It is possible to accurately control the amount of muddy water supplied via 16 depending on the situation.

In the present embodiment, the case has been described as an example in which the table data of the density and the ultrasonic attenuation amount of one type of soil is stored in the memory 42. However, when actually constructing a tunnel using a shield machine, the type of sediment taken into the chamber 14 changes depending on the ground. Therefore, it is preferable to carry out a boring survey of the ground or the like along the tunnel route in advance to check the earth and sand located on the tunnel excavation route. Then, the correlation between the density of the investigated sediment and the ultrasonic attenuation is tabulated for each sediment and stored in the memory 42. As a result, the arithmetic circuit 44 can read out the table data of the earth and sand from the memory 42 according to the kind of earth and sand taken into the chamber 14 and accurately measure the density of the muddy water 100.

The present invention is not limited to the above embodiment,
Various modifications can be made within the scope of the present invention.

For example, in the above embodiment, the water injection pipe 16 and the drainage pipe
Although the case where the ultrasonic transmitting / receiving device is provided on both 18 has been described as an example, the present invention is not limited to this, and either one may be provided with the ultrasonic transmitting / receiving device only on the drain pipe 18, for example, if necessary. .

Further, in the above-described embodiment, the case where the transmission / reception of the ultrasonic wave toward the muddy water 100 is performed by using the ultrasonic wave transmitter / receivers 32 and 34 that both perform the transmission and the reception has been described as an example. However, the present invention is not limited to this, and a transmitter that only transmits ultrasonic waves and a receiver that only receives ultrasonic waves may be used in combination as necessary. In this case, at least two pairs of transmitters and receivers may be provided.

[Advantages of the Invention] According to the present invention, the muddy water injected into the shield chamber using the water injection pipe, and the flow velocity and the muddy water density of the muddy water discharged from the shield chamber using the drainage pipe,
There is an effect that it is possible to obtain a monitoring device for a muddy water type shield chamber which can perform accurate measurement in real time and has a simple structure.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a preferred example of a muddy water type shield excavator to which the present invention is applied, and FIG. 2 is an explanatory view showing an installation state of ultrasonic transceivers provided in a water injection pipe and a drain pipe. FIG. 3A is a side cross-sectional explanatory view thereof, FIG. 3B is a front cross-sectional explanatory view thereof, and FIGS. 3 and 4 show examples of correlation between muddy water density and ultrasonic attenuation rate. FIG. 5 is an explanatory diagram of waveforms of ultrasonic waves transmitted / received to muddy water, FIG. 5 (A) is an explanatory diagram of ultrasonic pulses transmitted to muddy water, and FIG. 5 (B) is muddy water. FIG. 6 is an explanatory view of the waveform of the ultrasonic wave attenuated in the inside, and FIG. 6 is an explanatory view showing a specific circuit configuration of the present embodiment. 14 …… Shield chamber, 16 …… Water injection pipe, 18 …… Drain pipe, 30a, 30b… Ultrasonic transceiver, 32, 34 …… Ultrasonic transceiver, 40 …… Transducer drive circuit, 42 …… Memory, 44 ... Arithmetic unit.

Claims (3)

[Claims] 1. A muddy water shield machine comprising: a water injection pipe for injecting water into a muddy water shield chamber; and a drainage pipe for discharging earth and sand which is taken into the muddy water shield chamber and slurried. At least one of the pipes, at least one pair of ultrasonic transceivers arranged to face each other at a predetermined angle with respect to the flow direction of the muddy water flowing in the pipe, and ultrasonic transmission / reception timings of the pair of ultrasonic transceivers And a calculator for calculating the flow velocity and density of the muddy water flowing in the pipe based on the ultrasonic attenuation, and a monitoring device in the muddy water shielded chamber. 2. The calculation unit according to claim 1, wherein the relation between the ultrasonic attenuation amount propagating in the muddy water and the muddy water density is stored as an attenuation amount table, and between the pair of ultrasonic transceivers. A monitoring device in a muddy water type shield chamber for calculating the density of muddy water flowing in a pipe, based on the amount of attenuation of ultrasonic waves transmitted and received by and the attenuation table. 3. The ultrasonic wave from any one of the pair of ultrasonic wave transmitters / receivers to the other ultrasonic wave transmitter / receiver according to any one of claims 1 and 2. A monitoring device in a muddy water shield chamber, which calculates a flow velocity of muddy water flowing in a pipe based on a propagation time and an ultrasonic propagation time from the other ultrasonic transceiver to one ultrasonic transceiver.