JPH09159623A - Method and apparatus for measuring size of solid in mixture fluid of solid and liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the size of invisible solid mixed into fluid accurately by radiating radio wave into a duct through which a mixed fluid of solid and liquid flows and measuring the receiving level of radio wave propagated through the fluid. SOLUTION: An insulating duct is jointed to the way of a steel duct through which muddy water containing solidified soil and sand flows. A plurality of pairs of transmission antenna T1 -T4 and receiving antenna R1 -R4 are secured to the outer circumferential surface thereof. A data processor 11 delivers commands to a transmitting switch circuit 13 and a receiving switch circuit 14 and connects a transmitter 12 and a receiver 15, at a predetermined time interval, with the antennas T1 -T4 , R1 -R1 . Pulses are then transmitted from the antennas T1 -T4 into the insulating duct and the pulse propagated through muddy water are received by the antennas R1 -R4 and inputted to the receiver 15. The processor 11 averages the amplitude of pulses received on four types of propagation paths intersecting while keeping an angle difference of 90 deg. and then calculates the dimensions of solidified soil and sand in the muddy water based on the transmittance of radio wave determined from the average amplitude.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid in a solid-liquid mixed fluid used for measuring the size of a lump of earth and sand contained in a mixed fluid of earth and sand used for muddy water shield work and the like. The present invention relates to a size measuring method and apparatus.

[0002]

2. Description of the Related Art In tunnel construction using a shield machine, it is necessary to discharge the earth and sand scraped off at the tip of the excavator from the inside of the tunnel during excavation to the outside. There are two methods for discharging the scraped sand to the outside of the tunnel. It is conventionally known that a lump (solidified body) is mixed and sent back to the ground on the rear side, where the solidified body is separated from the muddy water and discarded, and the rear side of the mud shield is excavated. In order to save labor by automating the work, it is desirable to apply the latter mud shield excavation method.

The muddy water shield method will be described with reference to the muddy water supply / drainage system diagram of FIG. Referring to the water supply / drainage system diagram of FIG. 6, an adjusting tank 6 for adjusting the density and viscosity of the muddy water supplied into the underground tunnel is provided in the above-ground portion.
1 is installed. The muddy water in the adjusting tank 61 whose density and viscosity have been adjusted is pressurized by the water supply pump 65, is sent to the inside of the shield machine 67 in the ground through the water supply pipe 66, and is passed through the cutter 68 at the tip end of this cutter. It is discharged into a space filled with dirt and muddy water during cutting formed between 68 and "Kiriha" (cut edge).

If the density or viscosity of the muddy water discharged toward the cut end is too small, the muddy water easily penetrates into the cut end, causing the cut end to collapse. On the contrary, if the density and viscosity of the muddy water are too large, the burden on the water supply system becomes excessive. Therefore, the density and viscosity of the muddy water in the adjusting tank 61 installed on the ground are adjusted so that the density and the viscosity of the muddy water discharged from the cutter 68 are maintained at desired values. Specifically, the density of the muddy water is adjusted by the amount of fresh water supplied from the fresh water tank 74 and the amount of viscosity supplied from the mud storage tank 63, and the viscosity of the muddy water is adjusted from the thickener storage tank 62. It is adjusted by the amount of an appropriate thickener such as CMC supplied.

The muddy water discharged from the tip of the shield machine into the cut end becomes muddy water having a higher density due to the mixture of the solidified body of earth and sand cut by the bit at the tip of the cutter 68, and the cutter 68. Through the drainage pipe 72 and is pressurized by the drainage pump 73 to receive the drainage pipe 7
It is carried in 7 to the ground. The earth and sand carried to the ground is applied to a vibrating and sieving device 78, and a solidified body having a particle size of a certain size is separated from water and dumped as earth and sand. The muddy water containing unseparable small-diameter sand is passed through the drain pipe 79 to adjust tank 61.
Is returned to.

As described above, in the muddy water shield method, it is important to measure and control the density of muddy water, and it is necessary to keep the flow rate to a certain large value in order to prevent sedimentation of muddy water. Flow measurement and management is also important. In order to measure the density and flow rate of this muddy water, electromagnetic flowmeters 79 and 74 and gamma ray density meters 70 and 75 are installed on the respective sides of the water supply pipe and the drainage pipe in front of the cutter.

Further, the size of the solidified body discharged backward together with the muddy water is a combination of the nature of the natural ground and the excavation conditions such as the hardness of the natural rock during excavation and the extent to which the cutter bit is projected toward the natural rock. Depending on the value, it changes over a range of several hundred times from 1 mm to several tens of cm. If the size of the solidified body becomes too small, the amount of the solidified body dissolved in the muddy water will increase, and it will not be sieved in the rear. As a result, separation work from muddy water becomes difficult, so it is necessary to maintain the size of the solidified body at a predetermined value or more.

The change in the size of the solidified body can be detected only after the separation work is actually performed. Therefore, this is fed back to the tip portion of the shield excavator from the rear side where the separation work of water and the solidified body is performed. By changing the excavation conditions such as the protrusion amount of the bit of the cutter blade of the excavator according to the change of the nature of the ground, the size of the solidified body is maintained at a certain value or more. In addition, a solidified body such as a solidified silt layer formed during excavation has a uniaxial compressive strength of several tens kg / cm ²
Because it is as hard as rock and stone, it doesn't break or melt much in the drainage pipe, and its size does not change much.

[0009]

In the shield excavation work described above, the length of the tunnel increases as the excavation work progresses, and the distance between the tip of the shield machine and the rear separation point of sediment is reduced. It may reach up to 2-3 km.
In the above-mentioned method of controlling the size of the solidified body, when the distance between the excavated portion and the rear separating point becomes large in this way, the delay of the feedback time from the rear to the excavating point becomes large and the stability of the control system deteriorates. However, as a result, there arises a problem that the size of the solidified body becomes too small or becomes larger than necessary.

[0010]

According to the method and apparatus for measuring the size of a solid in a solid-liquid mixed fluid according to the present invention, a radio wave is radiated into a conduit through which the solid-liquid mixed fluid flows, and this conduit is used. The radio wave propagating in the solid-liquid mixed fluid flowing therein is received, and the size of the solid in the solid-liquid mixed fluid is measured from the received level.

[0011]

According to an embodiment of the present invention, a solid size measuring device utilizing radio wave transmittance is relatively close to an excavation site such as in a shield excavator or in a tunnel immediately behind the shield excavator. A stable feedback system is formed by being installed in the middle of a pipeline at a location and feeding back the measurement results to the excavation site in a short time. At the excavation site, so that the size of the solid body measured by the device for measuring the size of the solid body contained in the mud becomes almost constant,
The excavation conditions such as the expansion and contraction length of the cutter bit and the rotation speed of the cutter, and the conditions for supplying and draining muddy water will be changed.

[0012]

FIG. 3 is a block diagram showing the configuration of a device for measuring the size of a solidified body in muddy water of a muddy water shield excavator according to one embodiment of the present invention. T1 to T4 are transmission antennas and R1
~ R4 is a receiving antenna, 11 is a data processor, 12
Is a transmitter, 13 is a transmission switch circuit, 14 is a reception switch circuit, 15 is a receiver, 16 is a timing control circuit, 1
Reference numeral 7 is a display / recording circuit.

FIG. 1 is a diagram showing the relationship between the transmitting antenna and the receiving antenna portion of the apparatus for measuring the size of the above-mentioned solidified body and the pipeline through which mud flows, and (A) shows B- in (B). FIG. 6B is a sectional view taken along the line B ′, and FIG. 6B is a sectional view taken along the line AA ′ in FIG.

A cylindrical electrically insulating pipe PP made of reinforced plastic is joined in the middle of a steel pipe SP in which water containing a solidified body of earth and sand flows. This steel pipe SP is
It corresponds to the drainage pipe extended into the shield machine and the water supply pipe in the water supply and drainage system shown in FIG. Four transmission antennas T1, T2, T are arranged along the outer peripheral surface of the insulating pipe PP.
3, T4 are fixed on this outer peripheral surface with an adhesive layer interposed.

Four receiving antennas R1, R2, R3 and R4 are fixed on the outer peripheral surface with an adhesive layer so as to face each of the transmitting antennas T1 to T4 with the central axis of the insulating tube PP interposed therebetween. Has been done. The adjacent transmitting antennas T1 to T4 and the receiving antennas R1 to R4 are electrically shielded from each other outside the insulating conduit PP by a shield SH made of a radio wave absorber such as ferrite.

The transmitting antennas T1 to T4 and the receiving antennas R1 to R4 have the same structure. That is, as shown in the plan view of FIG. 2 (A) and its BB ′ sectional view, which is a representative of the transmitting antenna T1, as shown in FIG. 2 (B), a dielectric material made of tetrafluoroethylene (TFE) or the like. A doublet antenna structure is shown in which isosceles triangular metal plates 22a and 22b made of a metal such as copper are attached on the substrate 21 with their vertices facing each other. The dielectric substrate 21 is curved with the same radius of curvature as the outer peripheral surface of the insulating tube PP so that the dielectric substrate 21 is bonded and fixed to the outer peripheral surface of the insulating tube PP without forming a gap. Each antenna represented by the transmitting antenna T1 is fixed on the outer peripheral surface of the dielectric substrate while arranging the short sides of the dielectric substrate along the circumferential direction of the insulating tube PP in FIG.

Each of the metal flat plates 22a and 22b is connected to the transmission switch circuit 13 of FIG. 3 through a feeder (feed line) that passes through an opening formed in the dielectric substrate 21. For further details of this doublet antenna, if necessary, the description of the utility model registration application previously filed by the applicant (Jpn.
11375).

Referring to FIG. 3, the data processor 11
Issues a switch selection command to the transmission switch circuit 13 and the reception switch circuit 14, thereby connecting the transmitter 12 to the transmission antenna T1 and the receiver 15 to the reception antenna R1. The data processor 11 activates the timing control circuit 16 when the connection of the transmitting and receiving antennas is completed.

The activated timing control circuit 16 repeatedly supplies a transmission timing signal having a constant period T as illustrated in the waveform diagram of FIG. 4 to the transmitter 12, and a delay time of a constant value τ from the transmission timing signal. Supplies to the receiver 15 a strobe pulse that increases cumulatively. As shown in the waveform diagram of FIG. 4, the transmitter 12 outputs a sharp transmission pulse having a constant peak level and a half width of about 3 nsec in synchronization with the transmission timing pulse. This transmission pulse is radiated from the transmission antenna T1 into the insulating pipe PP, and the transmission pulse propagating in the muddy water is received by the reception antenna R1.

The reception pulse of the reception antenna R1 is supplied to the receiver 15 through the reception switch circuit 14 and is sampled in synchronization with the strobe pulse supplied from the timing control circuit 16 until the next reception pulse appears. , That is, held for a period equal to the cycle T of the transmission timing signal. As a result, the received pulse is received while its time axis is expanded by T / τ times. For further details of the operation of the pulse radar utilizing the time axis extension based on this sample hold method, if necessary, the applicant of the present invention previously filed a patent application entitled "berthing speedometer" Tokuhei 7
78537 publication).

The data processor 11 has a transmitting antenna T.
When the transmission / reception of the pulse for a predetermined number of times using the pair of 1 and the receiving antenna R1 is completed, the receiver 15 receives the received pulse whose time axis is extended. Subsequently, the data processor 11 issues a switch selection change command to the transmission switch circuit 13 and the reception switch circuit 14 to change the connection of the transmitter 12 from the transmission antennas T1 to T2, and the receiver 15 from the reception antenna R1. After changing the connection to R2, the timing control circuit 16 is activated.

The activated timing control circuit 16 transmits the transmission timing pulse and the strobe pulse respectively to the transmitter 12 and the receiver 15 as in the case of transmitting and receiving the pulse using the transmitting antenna T1 and the receiving antenna R1.
To supply. The transmission pulse output from the transmitter 12 at a constant cycle is radiated from the transmission antenna T2 into the insulating pipe PP, and the transmission pulse propagating in the muddy water is received by the reception antenna R.
2 is received and sampled and held in synchronization with the strobe pulse.

The data processor 11 has a transmitting antenna T.
When the transmission / reception of the pulse for a predetermined number of times using the pair of 2 and the receiving antenna R2 is completed, the receiving pulse whose time axis is extended is received from the receiver 15, and the transmitter 12 is connected to the transmitting antenna T2 to change to T3. After changing the connection of the receiver 15 from the receiving antennas R2 to R3, the timing control circuit 16 is activated. Similarly, the transmission antenna 4 and the reception antenna R4 are used to transmit / receive the pulse and extend the time axis of the received pulse based on the sample hold.

The data processor 11 detects the amplitude v of the received pulse received from the receiver 15. When detecting the amplitude v of the received pulse, 90 ^° , 180 ^° and 270 ^° are mutually obtained by using four pairs of transmitting and receiving antennas.
Spatial averaging is performed on the amplitude V of the received pulse obtained for the four types of propagation paths that intersect while maintaining the angle of. The data processor 11 calculates the radio wave transmittance K from the spatially averaged amplitude v of the received pulse thus obtained, and from the calculated radio wave transmittance K, the size of the solidified body of the earth and sand in the muddy water is calculated. Calculate. Hereinafter, the relationship between the radio wave transmittance K and the size of the solidified body of earth and sand will be described.

In the pair of transmitting and receiving antennas shown in FIG. 1, the amplitude of the radio wave radiated from the transmitting antenna T1 is E
Let t be the amplitude of the radio wave received by the receiving antenna R1, and Er be the transmittance K of the radio wave. K = 20 log (Er / Et) = A + B + C + D + L ... (1)

However, A: reflection loss caused by reflection at the interface between the transmitting antenna and the insulating pipe PP and at the interface between the insulating pipe and muddy water when propagating from the transmitting antenna T1 to the surface of the muddy water B: muddy water Scattering loss caused by being scattered by solidified soil inside C: Absorption loss caused by being absorbed by fine particles in the muddy water D: Surface of the muddy water when propagating from the surface of the muddy water to the receiving antenna R1 Loss caused by reflection at the interface between the insulating pipe PP and the insulating pipe PP and at the interface between the insulating pipe PP and the muddy water L: Diffusion loss caused by diffusion of radio waves radiated from the transmitting antenna

For the diffusion loss L, the wavelength of the radio wave is λ,
The diameter of the insulating conduit PP is d and is approximated by the following equation. ^{L = 20 log (λ 2/} 4 πd 2) ···· (2) radio wave wavelength lambda is 1.0 m, if the diameter d is 0.1 m of the insulating pipe, the diffusion loss L is -18 dB. Further, based on the experience of the present inventor, when the diameter d of the insulating conduit is 0.1 m, it is expected that each loss term has a value in the following range. A≈C≈−20 dB, −10 dB ≦ D ≦ −3 dB

If the complex permittivity of water is ε ₁ , the complex permittivity of a solidified body of earth and sand is ε ₂ , and its shape is approximated by a spherical body with radius a, the scattering cross section σ of Rayleigh scattering is given by the following equation. To be σ = 4π (2π / λ) ⁴ a ⁶ [ABS ((ε ₂ −ε ₁ ) / (2ε ₁ + ε ₂ ))] ² ··· (3) However, ABS () is the numerical value in (). A symbol representing an absolute value, λ is a wavelength of a radio wave.

If the frequency of the radio wave is f, the following equation can be obtained from equation (3). σ∝a ⁶ f ⁴ ··· (4) The diameter of all the solid bodies existing in the propagation path of the radio wave is a,
Assuming that there are n in total, the scattering loss B is approximated by the following equation. B∝nσ∝na ⁶ f ⁴・ ・ ・ ・ (5)

The spatial density ρ (Kg / m ³ ) of the solid is
It is approximated by the following formula. ρ∝na ³ ... (6) By substituting the equation (6) into the equation (5), the following equation is obtained. B ∝ρa ³ f ⁴ ··· (7)

When Et is 10 v, for pure water, B = 0 dB and D = -3 dB are approximated to K = -61 dB, from which Er≈9 mv is obtained. B = 0 dB, D = -10 dB for muddy water in which there are no solids that cause scattering and only minute particles that cause absorption are present at high density.
Approximately, K = -68 dB, and Er≈4 m
Get v. For muddy water in which both solid matter that causes scattering and minute particles that cause absorption are present at high density,
Approximating B = −20 dB and D = −10 dB gives K = −88 dB, from which Er≈0.4 mv is obtained. The received electric field in such a range of magnitude is a sufficiently practical value.

From the equation (7), the frequency f of the radio wave is fixed,
Radio wave transmittance K, which changes according to the magnitude of scattering loss B,
In this embodiment, by detecting the amplitude v of the reception pulse when the amplitude of the transmission pulse is fixed to a constant value, the size a of the solidified body in the muddy water can be known. FIG. 5 shows an example of the relationship between the amplitude mv of the received pulse and the diameter a of the solidified body in the muddy water when the frequency component f of the radio wave included in the pulse is kept constant. By measuring the spatial density ρ of the solidified body, which is the parameter in FIG. 5, using an appropriate method other than the transmission / reception of radio waves such as the γ-ray densitometer illustrated in FIG. 6,
The size a of the solid can be measured separately.

The above-mentioned measurement of the density ρ of the solidified body of earth and sand is
Irradiate radiation such as gamma rays and neutron rays to a solid-liquid mixed fluid in which mud and flowing solids flowing in the pipeline are mixed, and measure the amount of reflection and transmission thereof, and to keep this at a constant value, It can be realized by things. Regarding the method of measuring the density using this radiation, if necessary, we announced the lecture number 799,800 at the 27th Geotechnical Research Conference held in June 1992 as "For soil compaction management. Nondestructive Testing Methods (Part 11), (Part 12) "by Mitsugu Tanaka et al. And Civil Engineering Document 34-11 (1992).
Please refer to the contents of “Construction Technology Q & A” published in pp20-21.

The relationship between the diameter a of the solidified body of earth and sand calculated from the amplitude of the received pulse by the curve of FIG.
It corresponds experimentally in the early stage of excavation work. That is,
The diameter of the solidified body of the sediment is measured at the work site on the ground where the soil to be dumped is separated from the water, and the measured value agrees with the diameter of the solidified body of the soil calculated from the curve of FIG. Figure 5
The calibration of the curve is performed in advance.

At the time of this calibration, the diameter of the solidified body of earth and sand in the mud water is intentionally changed by changing the expansion and contraction length of the bit of the cutter of the excavator, the rotation speed of the cutter, and the like. Since such a calibration is performed at the start of excavation where the distance between the excavation point and the separation point from the muddy water is short, the error based on the time difference between the change in the manipulated variable and the detection of the resulting result is small.

In the above, in order to improve the detection accuracy, the case of the pulse radar accompanied by the time axis extension based on the sample hold is exemplified. However, if a slight decrease in accuracy is acceptable, a normal pulse radar that does not perform time-axis expansion can be applied.

Although the case of the pulse radar has been exemplified,
The present invention is not limited to this, and a sine wave may be transmitted or received in a burst or continuously as long as the level of the received radio wave can be measured.

Further, the structure in which four pairs of transmitting and receiving antennas are arranged along the outer peripheral surface of the insulating pipe has been exemplified, but the number of pairs is three pairs, two pairs, one pair, etc.
Alternatively, an appropriate number greater than 4 pairs can be selected.

Further, although a configuration using a wideband doublet antenna as an example of the transmitting / receiving antenna has been exemplified, other appropriate forms of transmitting / receiving antennas can be applied instead.

Further, the measuring method and apparatus of the present invention have been described by taking as an example the case of measuring the size of the solidified body of earth and sand in the muddy water of the shield machine. However, the method and apparatus for measuring the solid size of a solid-liquid mixed fluid according to the present invention is
It can also be applied to the measurement of the size of solids in various solid-liquid mixed fluids flowing in pipelines such as in a manufacturing plant or a waste liquid treatment plant.

[0041]

As described in detail above, the method and apparatus for measuring the size of a solid in a solid-liquid mixed fluid according to the present invention propagates a radio wave into the solid-liquid mixed fluid flowing in a pipe,
Since the size of the solid is measured by measuring this propagation loss, it is possible to accurately detect the size of the mixed solid, which is difficult to visually observe.

In particular, when the method and apparatus of the present invention are applied to the shield construction method, the method and the apparatus can be installed in the pipeline very close to the excavation site such as inside the excavator or in the tunnel behind the excavator, and the measurement result can be obtained in a short time. There is an advantage that a stable feedback system is formed by being fed back to the excavation site.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a part of a transmitting / receiving antenna of a measuring device for a size of a solidified body of earth and sand in a muddy water of a shield machine according to an embodiment of the present invention together with a pipeline through which the muddy water to be measured flows. Is.

FIG. 2 is a plan view (A) and a cross-sectional view (B) illustrating the structure of a transmission / reception antenna of the measurement apparatus of the above-described embodiment.

FIG. 3 is a block diagram showing the overall configuration of the measuring apparatus of the above-mentioned embodiment.

FIG. 4 is a waveform diagram for explaining the operation of the measuring apparatus of the above-described embodiment.

FIG. 5 is a conceptual diagram showing an example of the relationship between the diameter of a conglomerate of soil in water and the amplitude of a received pulse, which is measured by the measuring device of the above embodiment.

FIG. 6 is a system diagram showing a typical example of a water supply / drainage system of the muddy water shield excavation method.

[Explanation of symbols]

 T1 to T4 Transmit antenna R1 to R4 Receive antenna SH Radio wave shield SP Steel pipe PP Insulation pipe 11 Data processor 12 Transmitter 13 Transmit switch circuit 14 Receive switch circuit 15 Receiver 16 Timing control circuit 21 Dielectric substrate 22a, 22b Metal flat plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Iku Sato 1-61 Sakaemachi, Ageo City, Saitama Prefecture Toda Construction Ageo Dormitory Room 309 (72) Inventor Toshimitsu Nozu 6-22-12 Tamadaira, Hino City, Tokyo

Claims (6)

[Claims] 1. A radio wave transmission / reception means for transmitting a radio wave into a pipe in which a solid-liquid mixed fluid in which a solid and a liquid are mixed and flowing the solid-liquid mixed fluid, and a radio wave transmitting / receiving means for receiving the radio wave. And a means for calculating the size of the solid in the solid-liquid mixed fluid from the level of the radio wave received by the transmitting / receiving means. 2. The apparatus for measuring the size of a solid in a solid-liquid mixed fluid according to claim 1, further comprising a radiation densitometer for measuring the spatial density of the solid in the solid-liquid mixed fluid. 3. The apparatus for measuring the size of a solid in a solid-liquid mixed fluid according to claim 1, wherein the spatial density of the solid in the solid-liquid mixed fluid is maintained at a substantially constant value. 4. The size of a solid in a solid-liquid mixed fluid according to claim 1, wherein a plurality of pairs of the radio wave transmitting / receiving means are installed along an outer peripheral surface of the conduit. Measuring device. 5. The solid-liquid mixed fluid according to claim 1, wherein the solid-liquid mixed fluid conveys a solidified body of earth and sand scraped off at a tip portion of a shield machine and the solidified body to a rear ground portion. The size of the solid in the solid-liquid mixed fluid is characterized by changing the conditions of excavation or mud water supply and drainage so as to keep the size of the solidified body of sediment in a predetermined range. measuring device. 6. A radio wave is radiated into a pipeline in which a solid-liquid mixed fluid in which a solid and a liquid are mixed, and the radio wave propagating in the solid-liquid mixed fluid flowing in the pipeline is received. A method for measuring the size of a solid in a solid-liquid mixed fluid, characterized in that the size of the solid in the solid-liquid mixed fluid is calculated from the above.