JPH07103553B2 - Viscosity measuring device for stable liquid in stable liquid method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a viscosity measuring device for a stable liquid in a stable liquid method used for underground excavation of a continuous underground wall or cast-in-place concrete pile, and a viscosity control using the same. Regarding the device.

[Prior Art] Conventionally, when excavating a ditch or a hole in the ground, a stable liquid method for filling a stable liquid in the excavated ditch is often used. In this stable liquid method, the hydrostatic pressure of the stable liquid is used. Due to the effect mainly of, it becomes possible to excavate the trench hole in the ground while preventing the excavation wall surface from collapsing and skin falling off.

The stabilizing liquid used at this time is required to have appropriate properties such as stability, specific gravity, fluidity, and film-forming property. Therefore, as the stabilizing liquid, for example, CMC water-soluble polymer (polymer) is mainly used in muddy water. A polymer-based stabilizing solution containing an additive as a component and a bentonite-based stabilizing solution containing an additive containing a bentonite fine powder as a main component in muddy water are often used.

By the way, in the case of stably excavating a groove or a hole by using such a stable liquid method, it is necessary to accurately and quickly detect the property of the stable liquid to be used, especially the viscosity.

In particular, in the recent stable liquid method, since the system is centrally managed by the computer, it functions as a sensor part of the computer and can measure the viscosity of the stable liquid supplied to the excavation groove accurately in real time. Development is needed.

[Problems to be Solved by the Invention] However, in the conventional viscosity measuring technique, it is not possible to accurately and in real time measure the viscosity of the stabilizing liquid that is supplied to the drilling ditch or discharged from the drilling ditch. .

FIG. 11 shows an example of a conventionally used funnel viscometer.

In the measurement procedure at this time, first, a measurer places the funnel-shaped container 12 on the stand 10 and presses the lower opening 12a with a finger. next,
The stabilizing solution pumped up from the stabilizing solution supply device is passed through a wire net of 0.25 mm to remove solids having a particle size of 0.25 mm or more, and then the container 12 is filled with 500 cc.

Next, the finger of the lower mouth 12a held by the measurer is released. At this time, a stopwatch measures the time until all the 500 cc of stabilizing solution flowing out from the funnel-shaped container 12 flows down to the container 14 placed at the bottom. Then, the viscosity of the stable liquid is obtained from the correspondence between the viscosity of the stable liquid and the measurement time.

However, such a conventional viscosity measurement technique has the problems described in detail below.

First, in this conventional technique, a measurer manually measures the viscosity of the stabilizing solution. For this reason, there is a problem that the measurement takes a lot of time and labor, and the measurement accuracy greatly varies depending on the number of staff.

Further, with such a conventional technique, the viscosity of the stabilizing solution supplied through the mud pipe cannot be continuously measured in real time. For this reason, when the property of the stabilizing liquid suddenly deteriorates during excavation by an excavator or the like, there is a problem that it cannot be detected in real time and its viscosity cannot be controlled to an appropriate value.

Further, since the measurement work is performed on site, there is a problem that the measuring device is easily soiled, cleaning and storage are troublesome, and the stabilizing solution can be managed only by the funnel viscosity.

In addition to this, there is also a method of using a rotary viscometer such as a VG meter, but even in this case, the measurer collects the stable solution each time, and the stable solution is measured using this sample, As in the case of using the funnel viscometer, there were the above-mentioned problems (1) to (3).

As described above, the conventional viscosity measurement technique cannot achieve automation and labor saving of the stable liquid method, which has been a major obstacle in promoting centralized management of construction by a computer.

The present invention has been made in view of such conventional problems, and a first object thereof is to provide a stable solution in a stable solution method capable of automatically and accurately measuring the viscosity of the stable solution in real time. It is to provide a liquid viscosity measuring device.

A second object of the present invention is to provide a stable liquid viscosity control device in a stable liquid construction method capable of automatically and in real time controlling the viscosity of the stable liquid supplied into the excavation groove.

[Means for Solving the Problems] In order to achieve the first object, the present invention supplies a stable liquid into the excavation groove through a mud pipe and at the same time through the mud pipe into the excavation groove. In the stable liquid method for discharging the stable liquid, the pressure measuring device, which is provided in at least one of the mud sending pipe and the mud discharging pipe, for measuring the pressure of the stable liquid flowing in the pipe line at at least two places, and And a viscosity calculating means for calculating the viscosity of the stable liquid based on the pressure difference between the pressures.

Moreover, in order to achieve the said 2nd objective, this invention is based on the viscosity of the stable liquid measured using the viscosity measuring device in any one of Claims (1)-(4), and it is inside a drilling slot. It is characterized in that a viscosity control means for controlling the viscosity of the supplied stabilizing liquid is provided.

[Operation] The present invention focuses on the fact that when a fluid flows in a pipeline, a pressure difference corresponding to the viscosity of the stable liquid is generated in the pipeline, and the viscosity of the stable liquid is measured from this pressure difference. It is characterized by.

Such viscosity measurement may be performed by using a predetermined hydraulic formula, or may be performed by using a correlation between the differential pressure of the stabilizing solution and the viscosity which is measured in advance.

(A) When performing viscosity measurement using a hydraulic formula First, the case where viscosity measurement is performed using a predetermined hydraulic formula will be described.

In the measuring device of the present invention, a pressure measuring device for measuring the pressure of the stabilizing liquid flowing in the pipeline in at least two places is provided in either the pipeline of the mud feeding pipe or the drainage pipe into the excavation ditch. Set up. Then, the viscosity calculation means measures the viscosity of the stable liquid flowing in the pipeline in real time from the differential pressure of the measured pressure (friction loss head h of the stable liquid flowing in the pipeline) using the following hydraulic formula. is doing.

That is, the differential pressure of the stabilizing liquid flowing in the pipeline, that is, the friction loss head h is obtained by the following equation (Darcy-Weisbach equation).

Further, λ in the equation (10) is a pipe friction coefficient, and generally,
It changes depending on the Reynolds number Re and the surface roughness of the tube wall. The value of λ for the turbulent flow in a hydraulically smooth circular pipe has the following proposed formula as a practical one.

Brasius equation (3 × 10 ³ ≤ Re ≤ 10 ⁵ ) λ = 0.3164Re ^-0.25 (11) Niclase equation (10 ⁵ ≤ Re ≤ 3 × 10 ⁶ ) λ = 0.0032 + 0.221Re ^-0.237 (12) On the other hand, Reynolds number Re is defined by the following equation, By measuring the friction loss head h, equations (10) and (10)
By transforming (10 '), the pipe friction coefficient λ under constant conditions
Can be calculated.

If Re is calculated from the thus obtained λ by using the equation (11) or the equation (12), the kinematic viscosity coefficient ν and the viscosity coefficient μ of the stable liquid can be back-calculated by the following equations.

Note that l: flow path length d: pipe diameter v: average flow velocity g: gravitational acceleration ρ: fluid density.

As described above, the differential pressure of the stable liquid measured by using the pressure measuring device, that is, the friction loss head h is substituted into the above (10) to obtain the pipe friction coefficient, and the pipe friction coefficient is obtained as the above (13 ′), ( 13")
By substituting into, the kinematic viscosity coefficient and the viscosity coefficient of the stable liquid can be calculated almost in real time.

(B) When the viscosity is measured by using the correlation between the differential pressure of the stable liquid and the viscosity which is measured in advance. Moreover, the viscosity of the stable liquid is not only measured by using the above-mentioned hydraulic formula, but is also stable in advance. The correlation between the differential pressure of the liquid pressure and the viscosity of the stable liquid may be measured and stored, and the correlation may be used.

For example, under a certain design condition, the relationship between the friction loss head h and the funnel viscosity F is experimentally measured, and based on the measured pressure difference of the stable liquid, that is, the friction loss head h,
The funnel viscosity F may be obtained using the correlation.
In this case, it is extremely effective when the funnel viscosity is specified as the control reference value.

As described above in (a) and (b), according to the present invention, the viscosity of the stabilizing liquid flowing in the mud pipe or the mud pipe can be automatically measured in real time. Therefore, by using this measured value, the viscosity of the stabilizing liquid supplied into the excavation groove via the mud pipe can be feedback-controlled in real time.

In particular, in the recent stable liquid construction method, centralized management of construction is performed by a computer. Therefore, the measuring device as in the present invention, which can accurately grasp the viscosity of the stabilizing liquid supplied into the excavation groove in real time, is extremely good as the sensor part of the computer.

[Embodiment] Next, a preferred embodiment of the present invention will be described in detail by taking a circulating underground continuous wall construction system as an example.

FIG. 1 (A) shows a preferred example of the circulating underground continuous wall construction system of the embodiment. The system of the embodiment uses the rotary excavator 20 to excavate the ground to form the excavation trench 10. At this time, the excavation trench 10 is filled with the muddy water 100 that functions as a stabilizing liquid. This muddy water 100 penetrates into the ground from the excavated surface and adheres to the soil particles, forms a mud film on the wall surface to stabilize the groove wall, and is a good replacement fluid for placing good concrete, In addition, it holds various soil and sand that are mixed during excavation, transports the slurry, and prevents accumulation on the wall surface.

In this embodiment, such muddy water 100 is supplied from the muddy water treatment plant 30 provided outside the excavation trench 10 by the water pump P ₁
Is supplied through the mud pipe 12. At this time, muddy water 10
Additives containing, for example, bentonite fine powder as a main component are mixed in 0 so as to function as a stabilizing liquid in these trenches.

FIG. 1B shows a part of the internal configuration of the muddy water treatment plant 30. The muddy water treatment plant 30 includes a muddy water treatment device 30a, a regulating tank 30b, a fresh water supply device 30c, and a thickener supply device 30d.
including. Then, the muddy water treatment device 30a removes sediment from muddy water returning from the inside of the excavation groove via the mud discharge pipe 14,
Moreover, muddy water is supplied to the adjusting tank 30b after each treatment such as adjusting the pH.

The fresh water supply device 30c supplies fresh water to the adjusting tank 30b, and the thickener supply device 30d includes the adjusting tank 30b.
Hebentonite fine powder is supplied. As a result, in the adjusting tank 30b, its viscosity, specific gravity and other properties are adjusted so that the muddy water functions as a good stabilizing liquid, and this recycled muddy water is supplied into the excavation groove 10 via the muddy water supply pipe 12. It will be.

In this way, the excavation trench 10 is filled with the muddy water 100 that functions as a stabilizing liquid.

Then, the rotary excavator 20 excavates the face 22 in such muddy water 100. This excavated earth and sand is excavator 20
It is agitated with muddy water 100 that functions as a stable liquid inside,
It is slurried. Then, by the operation of the sludge pump P1, it flows toward the muddy water treatment plant 30 through the inside of the sludge pipe 14.

At this time, in the slurry muddy water 100, the particles of earth and sand are surrounded by the stabilizing liquid, their ionization is prevented, and the specific gravity is kept light. For this reason, the sediment particles flow smoothly in the sludge discharge pipe 14 without causing sedimentation, that is, causing the above.

What is important in this is that the excavation trench 10
It is to maintain the viscosity of the muddy water 100 supplied to the tank at a value such that it functions sufficiently as a stabilizing solution.

The feature of the present invention is that when a viscous fluid flows in the pipeline, attention is paid to the fact that a predetermined pressure difference occurs in the pipeline, and by measuring this pressure difference, the viscosity of the muddy water 100 can be measured in almost real time. It is possible to automatically measure with.

For this reason, at least two pressure regulators 40a, 40b are provided in the mud pipe 12, and the pressures Pa, Pb of the muddy water 100 are measured at at least two points in the conduit 12.

It is preferable that these pressure side measuring devices 40a and 40b are provided at a predetermined interval 1 in the straight pipe portion of the mud pipe 12 as shown in FIG. 3 (A). In the embodiment, l = 10 m is set.

Further, the mud pipe 12 used in the underground continuous wall construction system is often formed of a soft member. Therefore, in the embodiment, the straight pipe made of steel is arranged in the horizontal portion of the mud feed pipe 12, and the pressure measuring devices 40a and 40b are provided on the sludge discharge pipe 12 made of the steel straight pipe.

FIG. 3 (B) shows a pressure measuring device 40 used in this embodiment.
The specific configuration of is shown. Example pressure gauge 40
Includes a flange 42 sealed by liquid encapsulation, a detection unit main body 44 including a pressure detection unit, and a tube 46 for conducting the enclosed liquid between the both.

The flange 42 has a diaphragm 41 attached to the mud water 100 flowing in the mud pipe 12 so that the pressure of the mud water 100 flowing in the mud pipe 12 changes with the pressure of the enclosed liquid via the diaphragm 41. It appears and this is a tube
It is detected by the pressure detection unit of the detection unit main body 44 via 46.
It is preferable that the pressure detecting portion is formed using a strain gauge made of silicon or the like.

In the embodiment, as shown in FIG. 3 (A), in order to equalize the pressure loss in the tubes 46a, 46b of the pressure detectors 40a, 40b, the detection unit bodies 44a, 44b are provided with flanges 42a, 42b.
It is located almost in the middle of the installation position of a and 42b. As a result, even if there is a pressure loss in the tubes 46a and 46b, this is uniformly canceled and the pressure difference between the two measurement points can be accurately obtained.

Between the pressure Pa, Pb measured using the two pressure measuring devices 40a, 40b configured in this way and the head loss h per unit length of the muddy water 100 in the pipeline 12, There is a relationship shown.

h = (Pa−Pb) / l (10 ″) l; distance between the pressure measuring devices 40a and 40b provided in the straight pipe portion.

Therefore, by substituting the pressures Pa and Pb detected by the pressure measuring devices 40a and 40b into (10 ″), the head loss h (differential pressure) of the muddy water 100 in the mud pipe 12 can be accurately obtained. .

This head loss h is generally expressed by the following equation in the horizontal portion of the straight pipe.

h: head loss of straight pipe (m) λ: friction coefficient of pipe d: inner diameter of pipe (cm) g: 9.8 (m / s) Therefore, if the velocity v of the muddy water 100 and the inner diameter d of the mud pipe 12 are known, the pipe friction coefficient λ of the mud pipe 126 can be obtained from the above equation (10).

This pipe friction coefficient λ is the Reynolds number R of the muddy water 100 described above.
There is a relationship shown in the following equation with e.

Brasius's formula (3 × 10 ³ ≦ Re ≦ 10 ⁵ ) λ = 0.3164Re ^-0.25 … (11) Niclase's formula (10 ⁵ ≦ Re ≦ 3 × 10 ⁶ ) λ = 0.0032 + 0.221Re ^−0.237 … (12) Therefore, if the pipe friction coefficient λ of the mud pipe 12 is obtained from the above equation (10), the Reynolds number Re of the mud water 100 can be calculated from the above (11), (1
It can be calculated backward from equation (2).

Also, the Reynolds coefficient R of the muddy water 100 thus obtained is
e is generally represented by the following equation.

Re: Reynolds number v: Flow velocity (m / s) d: Inner diameter of pipe (m) λ: Coefficient of kinematic viscosity (m ² / s) Therefore, the Reynolds number Re of muddy water 100 can be calculated from the above equation (11) or (12). Then, by substituting the Reynolds number Re, the flow velocity v of the muddy water 100, and the inner diameter d of the muddy water pipe 12 into the equation (13), the kinematic viscosity coefficient λ of the muddy water 100 can be obtained.

At this time, there is a relationship between the kinematic viscosity coefficient ν of the muddy water 100 and the viscosity coefficient μ as shown by the following equation using the muddy water density ρ as a parameter. This is shown in the diagram in FIG.

ν: Dynamic viscosity coefficient (m ² / s) μ: Viscosity coefficient (kgf * s / m ² ) ρ: Density of fluid (kgf / m ² ) Therefore, obtain the kinematic viscosity coefficient ν and the density ρ of muddy water. Thus, the viscosity coefficient μ of the muddy water 100 can be calculated.

Thus, according to the present invention, the viscosity of the muddy water 100 can be calculated in real time by measuring the pressure of the muddy water 100 flowing in the mud pipe 12 with at least two points by the pressure measuring devices 40a and 40b. .

By the way, among the coefficients of the above equations, the inner diameter d of the mud pipe 12, the flow v of the muddy water 100, the density ρ, etc. can be obtained in advance by measurement.

However, the flow velocity v and the density ρ of the muddy water 100 are not always constant. In this embodiment, in order to enable more accurate measurement, the mud pipe 12 is provided with a flow velocity / density measuring device 50.
The flow velocity v and density ρ of the muddy water 100 flowing inside 12 are detected in real time. Therefore, the viscosity of the muddy water 100 can be measured more accurately by substituting the velocity v and the density ρ of the muddy water 100 obtained in this way into the above equations.

FIG. 4 shows a specific structure of the flow velocity / density measuring device 50. Measuring device 50 of the embodiment, a side wall of the mud pipe 12, a pair of ultrasonic transceivers 52, 54 arranged so as to intersect at a predetermined angle θ with respect to the flow method of the muddy water 100 flowing therein, and the flow velocity. And a calculator 56 for calculating the density.

Then, the arithmetic unit 56 includes the pair of ultrasonic transceivers 5
2, 54 is used to measure the flow velocity v of the muddy water 100 flowing in the mud pipe 12 as follows. That is, the propagation velocity C of the ultrasonic wave in the stationary liquid depends on the type of liquid, the temperature and the pressure. If it is fixed, it will be a constant value, 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 is increased by the flow velocity, and if the flow direction is opposite, the flow velocity is decreased by the flow velocity.

Therefore, the calculation unit 56 is configured to include the pair of ultrasonic transceivers 5
2,54 are alternately driven to transmit and receive ultrasonic pulses,
A forward propagation time t ₁ and a backward propagation time t ₂ are measured for 100 flows. Propagation time t ₁ , t obtained at this time
It is known that ₂ has the following relationship with the flow velocity v of the muddy water 100.

From equations (6) and (7) However, v = flow velocity (m / s) L = distance between transmitter and receiver (m) θ = angle formed by ultrasonic wave propagation axis and central axis of pipe C = ultrasonic wave propagation velocity in stationary mud (m / s) ) Then, the arithmetic unit 56 substitutes the measured propagation times t ₁ and t ₂ into (8) above to obtain the muddy water flowing in the mud pipe 12.
The flow velocity v of 100 is calculated and output in real time.

In this case, as can be seen from the equations (8), the relationship between the reciprocal of the propagation time and the flow velocity is linearly proportional, and its linearity is very good. ), Since the term of the ultrasonic wave propagation velocity C included in the equation (7) is deleted, the flow velocity v can be obtained regardless of the type, temperature and pressure of the muddy water.

Further, the arithmetic unit 56 of the embodiment is the ultrasonic transmitter / receiver of the pair.
Using 52 and 54, the density ρ of the muddy water 100 flowing in the mud pipe 12 is measured as follows.

That is, when ultrasonic waves are transmitted and received between the pair of ultrasonic wave transmitters / receivers 52, 54, the transmitted ultrasonic waves 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 transceiver 52 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 54 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.

6 and 7 show measurement 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. 6 shows the data when kaolin is mixed in the muddy water, and FIG. 7 is the data when lime and gypsum are mixed in the muddy water.

As is clear from these measurement data, the amount of ultrasonic attenuation has a proportional relationship with the solid concentration in mud water. Therefore, by transmitting and receiving ultrasonic waves in the muddy water 100 as shown in FIG. 5, the density ρ of the muddy water 100 (the volume concentration of the amount of dry sand contained in the muddy water 100 is calculated based on the attenuation of the received ultrasonic waves. ) Can be measured in real time. At this time, the mud concentration can be accurately measured 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.

Next, in order to verify the effect of the present invention, muddy water 100 (stabilizing liquid) was added to a circular pipe having a pipe diameter d = 20 cm at a flow velocity of v = 1.82 m / sec (approximately 3.4 m ³ / min in terms of flow rate). Is supplied at this time, l = 10 cm
An explanation will be given assuming that the pressure in the pipe is measured by setting the interval.

First, a case will be described in which an appropriate value of h is set, λ and Re are inversely calculated, and this is substituted into the above equation (13) to calculate the kinematic viscosity coefficient ν.

Substituting the above constants into the equations (10 ') and (13), λ and ν
Is expressed by the following equation.

With this, if the design conditions (d, l, v, ρ) are determined, λ, Re can be determined by measuring the head loss h, that is, the differential pressure of the mud flowing in the pipe, and by this, the kinematic viscosity can be determined. It is understood that the coefficient and the viscosity coefficient can be calculated back.

According to the test results, the head loss h and the log ν have a substantially linear relationship within the range of practical design conditions as shown in FIG.

FIG. 8 shows a specific circuit configuration of the circulating underground continuous wall construction system of this embodiment.

In the present embodiment, the pressures Pa and Pb of the muddy water 100 detected by the two pressure measuring devices 40a and 40b and the velocity v and the density ρ of the muddy water 100 detected by the flow velocity / density measuring device 50 are respectively calculated by the viscosity calculation circuit 60. Is output to.

In this case, the correspondence relationship between the differential pressure h of the muddy water 100 and its viscosity is remarkable in the straight portion of the mud pipe 12. For this reason, the pressure measuring devices 40a and 40b of the embodiment are provided at a constant interval 1 on the straight line portion of the mud pipe 12.

The viscosity calculation circuit 60 includes a differential pressure calculation unit 62, a memory 64, and a viscosity calculation unit 66.

In the memory 64, the constants shown in the equations (10) to (14),
That is, data such as the distance 1 between the pressure measuring devices 40a and 40b and the inner diameter d of the mud pipe 12 are stored.

Then, the differential pressure calculation unit 62 substitutes the detected pressures Pa and Pb of both pressure measuring devices 40a and 40b and the constant l read from the memory 64 into the formula (10 ″), and flows in the mud pipe 12. The head loss h of muddy water is calculated, and the calculation result is output to the viscosity calculation unit 66.

Then, the viscosity calculation unit 66 uses the data stored in the memory 64 and the head loss h, the flow velocity v, and the density of the muddy water 100 that are measured in real time using the pressure measuring devices 40a and 40b, the flow velocity / density detection device, and the like. By substituting ρ into the equations (10) to (14), the viscosity coefficient μ of the muddy water 100 flowing in the mud pipe 12 is calculated in real time, and the calculated value is output to the central control unit 70. .

The central control unit 70 compares the viscosity coefficient μ of the muddy water 100 thus measured in real time with a desired reference value, and determines whether or not the viscosity coefficient μ of the muddy water 100 is appropriate.

Then, the viscosity of the measured muddy water 100 is always an optimum value, the fresh water supply device 30c of the muddy water treatment plant 30, the thickener supply device 30b is controlled, an additive added in the muddy water 100,
For example, the amount of bentonite fine powder is feedback-controlled.

Thus, according to the present invention, the viscosity of the muddy water 100 supplied to the excavation trench 10 can be automatically measured in real time.
It can be controlled and feedback controlled so that its viscosity is always optimal.

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

For example, the viscosity measurement of mud is not limited to the case of using the hydraulic formula, but the correlation between the differential pressure of the mud pressure and the viscosity of the mud is measured and stored in advance, and this correlation is used. You can go.

Fig. 10 shows the correlation between the friction loss head h and the funnel viscosity F obtained in this way. As shown in Fig. 10, the correlation between the two is almost linear, and its linear regression line is Shimizu. The calculated value in the case of passes. In this case, if d, l, and v change, it is expected that a straight line of f = αh + β will be obtained. Therefore, the friction loss head h in the pipe can be measured, and the funnel viscosity F can be obtained based on the measured friction loss head h using the correlation.

Further, in the above-mentioned example, the case where the one containing bentonite fine powder as the main component was used as an additive to muddy water was described as an example, but the present invention is not limited to this, and stability using an additive other than this Liquid, eg CMC water-soluble polymer
It can also be applied to the case of measuring the viscosity of a polymer-based stabilizing solution containing as a main ingredient.

Further, in the above-described embodiment, the case where the viscosity measuring device is provided in the mud pipe has been described as an example, but the present invention is not limited to this, and may be provided in the mud pipe, for example, if necessary. At this time, since mud water and excavated earth and sand are mixed and slurried in the mud pipe, the viscosity of the mud supplied to the excavation trench 10 is controlled in real time based on the viscosity of the slurried mud. It becomes possible to do.

Further, in the above-mentioned embodiment, the case where the viscosity control is performed in the muddy water treatment plant is described as an example, but the present invention is not limited to this, and if necessary, for example, a mud pipe, a thickener directly in the excavation groove May be supplied to control the viscosity.

Furthermore, another known circulation system, such as a normal circulation system, can be applied.

Further, in the above embodiment, the case where the present invention is applied to a circulating underground continuous wall construction system has been described as an example, but the present invention is not limited to this, for example, underground excavation for cast-in-place piles and various other types. It can also be applied to the stable liquid method.

[Effects of the Invention] As described above, according to the present invention, the viscosity of the stable liquid in the stable liquid construction method capable of automatically and in real time measuring the viscosity of the stable liquid supplied into the excavation groove hole. There is an effect that a measuring device can be obtained.

In particular, in the recent stable liquid construction method, centralized management of the construction site is performed by a computer, but a measuring device that can accurately grasp the viscosity of the stable liquid supplied in the excavation groove in real time as in the present invention is It is extremely effective as a sensor part of a computer.

Furthermore, according to the present invention, since the viscosity of the stable liquid supplied into the excavation groove can be feedback-controlled based on the measured viscosity of the stable liquid, the stable liquid supplied into the excavation groove can be controlled. It is possible to control its viscosity in real time so that it always functions well.

[Brief description of drawings]

1 (A) and 1 (B) are explanatory views showing a preferred example of a stable liquid construction method to which the present invention is applied, and FIG. 2 is a characteristic showing a relationship between a kinematic viscosity coefficient of a fluid and a viscosity coefficient. FIGS. 3 (A) and 3 (B) are external explanatory views showing a specific configuration of the pressure measuring device used in this embodiment, and FIG. 4 is a flow velocity / density measuring device used in this embodiment. 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. ) Is an explanatory diagram of a waveform of ultrasonic waves attenuated in muddy water, FIGS. 6 and 7 are explanatory diagrams showing an example of a correlation between the muddy water density and the ultrasonic attenuation rate, and FIG. 8 is the present embodiment. Fig. 9 shows a concrete rotation configuration of Fig. 9, Fig. 9 shows the Reynolds number and pipe friction coefficient calculated by using the hydraulic formula, FIG. 10 is an explanatory diagram showing the relationship between the head loss h and the funnel viscosity F, and FIG. 11 is an explanatory diagram showing an example of a conventional viscosity measuring device. 40a, 40b ... pressure measuring device, 50 ... flow velocity / density measuring device, 60 ... viscosity calculating circuit, 100 ... muddy water.

Claims (6)

[Claims] Claim: What is claimed is: 1. A stable liquid construction method for supplying a stable liquid into an excavation groove through a mud pipe and discharging the stable liquid inside the excavation groove through a mud pipe. A pressure measuring device which is provided in at least one of the above, and which measures the pressure of the stable liquid flowing in the pipeline at at least two points; and a viscosity calculating means for calculating the viscosity of the stable liquid based on the differential pressure of the measured pressure, An apparatus for measuring the viscosity of a stable liquid in a stable liquid method, comprising: 2. The stable liquid method according to claim 1, wherein the viscosity calculating means calculates the viscosity of the stable liquid using a predetermined hydraulic formula based on the differential pressure of the measured pressure. Viscosity measuring device for stable liquid. 3. The velocity / density measuring device according to claim 2, comprising a velocity / density measuring device for measuring the velocity and density of the stable liquid flowing in the pipe line, wherein the viscosity calculating means has a differential pressure of the measured pressure and a velocity of the stable liquid. And a viscosity measuring device for a stable liquid in a stable liquid method, wherein the viscosity of the stable liquid is calculated based on the density. 4. The viscous calculation means according to claim 1, wherein the correlation between the differential pressure of the stable liquid and the viscosity of the stable liquid is stored in advance, and the stable liquid is calculated based on the differential pressure of the measured pressure. A viscosity measuring device for a stable liquid in a stable liquid method, wherein the viscosity of the stable liquid is calculated. 5. The viscosity measuring device according to any one of claims 1 to 4, and the stabilizing liquid supplied into the excavation groove hole based on the viscosity of the stabilizing liquid measured by the viscosity measuring device. A viscosity control device for controlling the viscosity of a stable liquid in a stable liquid method, comprising: 6. The viscous control means according to claim 5, wherein the viscosity control means includes a thickener supply device for increasing the viscosity of the stabilizing liquid and a fresh water supply device for reducing the viscosity of the stabilizing liquid. Viscosity control device for stable liquid in stable liquid method.