JP6180290B2 - Visualization device for plastic fluidization in the chamber of shield machine - Google Patents

Description

  The present invention relates to an apparatus for visualizing plastic fluidization of excavated earth and sand in a chamber of a shield machine.

The shield machine using mud pressure employs a structure in which the excavated sediment is plasticized and fluidized in the chamber, and the soil in that state is carried out of the chamber by a screw conveyor.
At that time, the excavation soil is characterized by excavation while balancing the face pressure with mud soil plastically fluidized.
In that case, whether or not the excavated earth and sand and the fluidizing agent are uniformly mixed and in a good fluidized state is a big problem.
However, at present, it is not known whether the plastic fluidization process has been performed uniformly in a closed chamber.
As a result, solidified sand that has not been fluidized is clogged inside the screw and the outer tube in the conveyor and becomes clogged, resulting in an obstacle to soil removal.
In addition, if the excavated soil is not sufficiently fluidized, the imperviousness of the mud becomes incomplete, and water pressure may cause troubles such as dripping of water from the discharge port of the screw conveyor.
A technology as described in Non-Patent Document 1 has been developed as an invention focusing on this point, but it is performed by constructing an analysis model using sediment flow analysis based on viscous fluid dynamics.

6-023 of the 59th Annual Scientific Lecture Meeting (September 2004) of the Japan Society of Civil Engineers

  The chamber visualization technology described above is an attempt to perform hydrodynamic analysis from the shape, piping, operation, rotational torque, etc. of the stirring fins in the chamber, and a device that directly measures the plastic flow state during stirring, There is no way.

The visualization device for plastic fluidization in the chamber of the shield machine according to the present invention that solves the above-described problems is a plurality of sound wave transmitters arranged in the chamber of the mud pressure shield machine, and is transmitted by the sound wave transmitter. A sound wave receiver that receives the received signal, a measuring device that measures the sound speed between the sound wave transmitter and the sound wave receiver from the signal received by the sound wave receiver, and a sound speed that is measured in advance according to the fluidization state of the target sediment The comparison device comprises a table and a comparison device that compares the speed of sound measured between the sound wave transmitters and receivers, and a visualization device that displays the comparison results in different colors according to the degree of comparison.
The apparatus of the present invention is configured so that phase modulation can be performed when a signal is transmitted from the sound wave transmitter.
Moreover, the apparatus of this invention is comprised so that it can transmit, without making the transmission time of a sound wave correspond in several sound wave transmitters.
The apparatus of the present invention calculates the position from the rotation angle of the stirring blade, etc. when there is a member whose position changes with time such as the stirring blade in the chamber. A sound wave is transmitted from the sound wave transmitter when it reaches an angle that is not located in the middle of the sound wave receiver.

Since the visualization device for plastic fluidization in the chamber of the shield machine of the present invention is as described above, the following effects can be obtained.
<1> Rather than theoretical analysis, the state of plastic fluidization can be grasped and visualized in a chamber in which earth and sand and a fluidizing agent are actually mixed, and its reliability is high.
<2> As a result, the excavated soil can be drained smoothly, and the clogging of the screw conveyor and the occurrence of water are unlikely to occur, and efficient excavation work is possible.
<3> Further, it is possible to prevent breakage of machines and parts to be kneaded and discharged, and to improve maintainability.

Explanatory drawing of the chamber of a mud pressure type shield machine. Explanatory drawing of the Example of the arrangement | positioning state of the acoustic wave transmitter-receiver in a chamber. Explanatory drawing of the Example which analyzes the reception time by a phase modulation wave. Explanatory drawing of the example of the table which shows the relationship between the fluidization state calculated | required by the test, and sound velocity. Explanatory drawing of the example which visualized fluidization of the earth and sand in a chamber. Explanatory drawing of the Example arrange | positioned in the state in which the stirring blade is not located between a sound wave transmitter and a sound wave receiver. Explanatory drawing of the Example of tomography analysis.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a preferred embodiment of a visualization apparatus for plastic fluidization in a chamber of a shield machine according to the present invention will be described in detail with reference to the drawings.

<1> Principle of the Present Invention The present invention determines the fluidization state by utilizing the difference in sound velocity of the soil after plastic fluidization after mixing the soil and plasticizer during excavation.
It is generally known that the speed of sound that propagates changes due to changes in the density, viscosity, stress, temperature, etc. of the target medium, but the causal relationship between these is clearly elucidated. Not.
In this respect, in the present invention, the change in fluidity of the actually excavated soil is regarded as the change in sound velocity, and the sound velocity is measured in advance and compared with the table to estimate how fluidized the soil in the chamber is. To do.

<2> Arrangement of Sonic Transmitter / Receiver As shown in FIG. 1, the mud pressure shield machine has a drilling blade b on a front rotating disk a, and a chamber c for taking in and stirring earth and sand on the rear surface.
The chamber c is a space between the rotating disk a and the partition wall d, and an inlet of the screw conveyor e is opened in a part of the partition wall d.
The sound wave transmitter 1a and the sound wave receiver 1b are arranged at a plurality of locations in the chamber c. (Figure 2)
Both can use another member, or can use the sound wave transceiver 1 which is an integrated member.
The sound wave transmitter 1a is a device that transmits a predetermined sound wave, and the sound wave receiver 1b is a device that receives a sound wave transmitted from the sound wave transmitter 1a. Can be used.
The sound wave transmitter 1a can be configured so that phase modulation can be performed when a signal is transmitted.
If comprised in that way, the sound wave transmitted from the sound wave transmitter 1a and other noise can be distinguished.

<3> Measurement of sound speed Time until a sound wave transmitted from one sound wave transmitter 1a reaches another sound wave receiver 1b is measured.
In this case, if the sound waves are simultaneously transmitted from the plurality of sound wave transmitters 1a, the arrival time to the sound wave receiver 1b cannot be determined.
For this purpose, the transmission time for each of the plurality of sound wave transmitters 1a is sequentially shifted slightly without matching.
Then, since a sound wave from a plurality of sound wave transmitters 1a,... Distributed in the chamber c is sequentially input to a certain sound wave receiver 1b, the speed of the sound wave transmitted through the interval between them is accurately measured. be able to.

<4> Position for Arrangement In the chamber c, there are stirring blades f that stir the earth and sand and the fluidizing agent.
If such an obstacle is interposed between the sound wave transmitter 1a and the sound wave receiver 1b, an accurate sound speed cannot be measured.
When such a member whose position changes with time exists, the position is calculated from the rotation angle of the stirring blade f or the like.
Then, at a time when the stirring blade f or the like reaches an angle that is not located between the sound wave transmitter 1a and the sound wave receiver 1b, a sound wave is transmitted from the sound wave transmitter 1a and received by the sound wave receiver 1b.
As a precondition at that time, the sound wave transmitter 1a and the sound wave receiver 1b are generated such that an instant in which all the straight lines connecting the sound wave transmitter 1a and the sound wave receiver 1b are not blocked by the plurality of rotating stirring blades f occurs. It is necessary to arrange. (Fig. 6)

<5> Creation of comparison table (FIG. 3)
A table is prepared in advance by measuring the relationship between the degree of fluidization and the speed of sound.
Then, if the sound speed value of the table is known, it is possible to know the state of fluidization at the sound speed value, that is, the kneading state of the earth and sand and the fluidizing agent.
As a table creation method, for example, when a sample of earth and sand at a construction site is obtained in advance, a difference in sound speed before and after plastic fluidization is obtained at a laboratory level and tabulated.
Alternatively, it is possible to sample the soil discharged during the construction and adopt a method of examining the sediment property, that is, the relationship between fluidization and sound speed.
In that case, it is possible to adopt a method of periodically updating the comparison table in a place where the geology changes during construction.

<6> Measuring Method Next, a method for determining the degree of fluidization using the above apparatus and visualizing it will be described.

<7> Sound wave transmission step A sound wave is sequentially transmitted from a plurality of sound wave transmitters 1a arranged at various locations in the chamber c.
In this case, as described above, both are arranged so that a straight line connecting the sound wave transmitter 1a and the sound wave receiver 1b is not interrupted by the stirring blade f or the like. Send sound waves.
Further, phase modulation (PRBS) or the like is performed to distinguish the transmitted sound wave from noise. (Figure 3)

<8> Sound wave reception step The sound wave transmitted in the above step is received by another sound wave receiver 1b.

<9> Sound velocity measurement process Since it is clear when the sound wave is transmitted by the sound wave transmitter 1a and when the sound wave is received by the sound wave receiver 1b, the sound wave is transmitted between the sound wave transmitter 1a and the sound wave receiver 1b by a known measuring device. Measure the speed of sound.
As described above, the speed of sound varies depending on the degree of fluidization of earth and sand, so that the difference in fluidization of earth and sand at each position in the chamber c can be grasped by the difference in sound waves.

<10> Comparison process Even if the difference in fluidization of earth and sand is found for each position in the chamber c, it cannot be determined whether the degree is suitable for discharging from the conveyor or the degree of kneading is insufficient.
Therefore, the sound speed value in the table of the relationship between the sound speed measured in advance and the degree of fluidization is compared with the sound speed value actually measured.
Then, the earth and sand existing between a certain sound wave transmitter 1a and a certain sound wave receiver 1b is insufficiently fluidized, or has been fluidized to an extent suitable for discharge, or the middle, or about a certain percentage, Such a judgment can be made.
This determination is made between all adjacent sound wave transmitters 1a and sound wave receivers 1b.

<11> Visualization process If the degree of fluidization of earth and sand between all adjacent sonic transmitters 1a and sonic receivers 1b can be determined, it is visualized.
Displaying the degree of fluidization by color coding or the like can be easily performed using known software. (Fig. 5)

<12> Use of results If this visualization is possible, it is possible to determine whether to discharge from the chamber c to the outside through the conveyor e, or to continue stirring, or to further stir by adding a fluidizing agent. .
In this case, since the kneading state inside the chamber c is visualized and displayed on the display, even an ordinary worker who has not received special education can easily determine and take the optimum action.

<13> Another embodiment (FIG. 7)
It is also possible to calculate the sound velocity distribution at each location by transmitting and receiving the sound wave transmitter 1a and the sound wave receiver 1b at a plurality of locations on the outer periphery of the champer and performing tomographic analysis on the result.
In that case, one transmission arranged on the outer periphery is received by all the other sound wave receivers 1b.
This transmission process is repeated sequentially.
If the inside of the chamber c is considered in a mesh shape, these synthesis speeds are measured.
From these sound speed results, the multiple simultaneous equations are solved to calculate the speed of each place.

1: Sound wave transmitter / receiver 1a: Sound wave transmitter 1b: Sound wave receiver c: Chamber f: Stirring blade

Claims (4)

A plurality of acoustic wave transmitters arranged in the chamber of the mud pressure shield machine,
A sound wave receiver for receiving a signal transmitted by the sound wave transmitter;
A measuring device for measuring the speed of sound between the sound wave transmitter and the sound wave receiver;
A sound speed table that measures and tabulates the relationship between the sound wave and the fluidized state according to the fluidized state of the target soil in advance,
A comparison device for comparing the sound speed between the sound wave transmitter and the sound wave receiver and the sound speed value of the sound speed table;
A visualization device for plastic fluidization in a chamber of a shield machine comprising a visualization device that displays a comparison result by color coding according to the degree of fluidization. Configured to be able to perform phase modulation when transmitting a signal from the above sound wave transmitter,
The visualization device of plastic fluidization in the chamber of a shield machine according to claim 1. In the plurality of sound wave transmitters, configured to be able to transmit without matching the sound wave transmission time,
The visualization device of plastic fluidization in the chamber of a shield machine according to claim 1. When a member whose position changes with time such as a stirring blade exists in the chamber,
The position was calculated from the rotation angle of the stirring blade, etc., and it was configured to emit sound waves from the sound wave transmitter when the stirring blades reached an angle that was not located between the sound wave transmitter and the sound wave receiver.
The visualization device of plastic fluidization in the chamber of a shield machine according to claim 1.

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