JPS6225696A - Disintegration survey instrument for shield construction - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] (Industrial application field) This invention relates to a collapse exploration device for shield construction,
In particular, it relates to a collapse exploration device suitable for shield construction using muddy water.

(Prior art) In shield work for tunnels, etc., the condition of the ground near the face of the shield machine is constantly monitored, and if a collapsed part is found, measures such as immediately reinforcing that part with an appropriate method are taken. must be done.

For this reason, as seen in Japanese Patent Publication No. 57-4800, for example, sound, especially ultrasonic waves, are radiated to the ground, and the condition of the ground is determined by the time difference of acoustic reflection from the ground and the received waveform. Probing equipment is provided.

By the way, shield construction using muddy water is especially carried out on sandy soil or on ground where there is a lot of spring water, such as sandy soil, and collapse of the face often occurs on this type of ground.

Conventionally, one way to prevent the collapse of the face was to increase the specific gravity of the muddy water used for excavation.

(Problems to be solved by the invention) In shield construction using muddy water as described above,
Since air bubbles and the like that are mixed in during mud making are interposed between the exploration device and the ground, the use of the above-mentioned ultrasonic exploration device has the following problems.

In order to increase the specific gravity of muddy water, it is generally necessary to increase the bentonite content in the muddy water, but mud is usually made by high-speed stirring for a long period of time, and air bubbles are mixed in during this stirring and kneading process.

For this reason, the muddy water supplied to the face etc. contains three parts: water, air bubbles, liquids such as bentonite, gases, and solids, and the refraction of ultrasonic waves at the interface of these objects with different properties. Diffuse reflection occurs, reducing directivity and greatly attenuating reflections from the ground, which impede exploration of the collapse.

The inventors confirmed through experiments that 88-2
When using 00KHz ultrasonic waves, the specific gravity of muddy water is 1.
When it was 2 or more, it was almost impossible to measure.

This invention has been made in view of the above-mentioned problems, and its purpose is to provide a collapse exploration device that is particularly effective for shield construction using muddy water of high specific gravity.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a shield machine for shield work in which mud is excavated while supplying muddy water to the face of excavated ground. It has an antenna unit for transmitting and receiving microwaves, and a transmitter and a receiver respectively connected to the antenna unit. It is characterized in that it receives signals and detects collapse based on these signals.

(Embodiments and Effects) Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

1 to 3 show an embodiment of a collapse exploration device for shield construction according to the present invention.

The device shown in the figure includes a shield machine 10 as shown in FIG.
An antenna section 18 for transmitting and receiving microwaves, for example, electromagnetic waves of several hundred MHz to several GHz, is disposed above the front part of the skin plate 12 and close to the face 14, that is, near the excavation cutter 16 of the shielding machine 10. It is set up.

The shield 1110 performs excavation and propulsion while supplying high specific gravity muddy water A containing a large amount of bentonite toward the face 14 from inside thereof.

The supplied high-density muddy water A flows around between the excavated earth 20 and the skin plate 12 due to the rotation and propulsion of the cutter 16 of the shield 1110, and is interposed on the upper surface of the antenna section 18 and the like.

The antenna section 18 is fitted into a window section 22 provided at the upper part of the skin plate 12, as shown in detail in FIG.

The window part 22 is inclined and recessed at an angle of approximately 45 degrees with respect to the skin plays 1 and 12, and the protective case 2 is installed inside the window part 22.
The antenna part 18 housed in 4 is fitted.

As shown in the plan view of FIG. 2(B), this antenna section 18 includes a transmitting antenna 18a and a receiving antenna 18b that are provided at a predetermined interval, and each antenna 18a, 18b is approximately the same. It is composed of a metal flat plate with a shape of a pair of triangles connected at their vertices.
Each of them is housed in a protective case 24 with appropriate elastic material, cushioning material, protective material, etc. interposed therebetween.

The antenna section 18 is connected to a linear drive device 28 via a drive shaft 26 whose lower end passes through the protective case section 24, and the direct drive device 28 can be, for example, a hydraulic or pneumatic cylinder.

Thereby, the antenna section 18 is made to protrude diagonally forward from the window section 22 so as to be movable forward and backward.

The antenna section 18 is also connected to a rotary drive device 30, and this rotary drive device 3o is composed of a direct-acting hydraulic cylinder 32 and a link mechanism 34, and controls the linear motion of the hydraulic cylinder 32, for example. The rotational force is converted into rotation by a link mechanism 34 such as a spline, and this rotational force is transmitted to the drive shaft 26.

Thereby, the antenna section 18 is rotationally driven.

An electric circuit, the outline of which is shown in FIG. 3, is connected to the antenna section 18.

That is, a transmitter 36 that transmits microwaves intermittently or continuously is connected to the transmitting antenna 18a, and a receiving amplifier 38 is connected to the receiving antenna 18b. a processing device 40 that performs calculations or waveform processing based on the
and a CRT 42 for monitoring the output signal of.

Further, although detailed illustration is omitted, a sensor 44 that detects the movement ω in the axial direction is connected to the drive shaft 26 that moves the antenna section 18 forward and backward. This sensor 44 is suitably a variable resistor whose slider moves together with the drive shaft 26.

Furthermore, the amount of movement of the drive shaft 26 in the rotational direction is also detected by a rotary encoder or the like.

Now, in the collapse exploration device configured as described above, first, the antenna section 18 is set at the position shown by the solid line in FIG.
Collapse of the excavated ground 20 above the skin plate 12 is investigated.

The probe transmits microwaves from the transmitter 36 to the antenna 18.
a, the microwave is transmitted from the antenna 18a toward the excavated ground 20, and the microwave reflected by the ground 12 is sent to the receiving antenna 1.
8b and received by the receiving amplifier 38, and based on these signals, the processing device 40 calculates the transmission/reception time difference, or the transmission/reception waveform displayed on the CRT 42.
A state of 0 is determined.

On the other hand, in the exploration of the face 14 side, first, the antenna part 18 is made to protrude diagonally forward of the skin plate 12 by the linear drive device 28, and then the antenna part 18 is protruded diagonally forward of the skin plate 12 by the rotary drive device 30.
Rotate 0 degrees.

As a result, the antenna section 18 faces toward the face 14 as shown by the two-dot chain line in FIG. 2, and in this state, if microwaves are emitted in the same manner as described above, the face 14 can be explored.

In conducting the above two surveys, 20. The aforementioned high-density water distribution A is interposed between the face surface 14 and the antenna section 18, but microwaves have stronger directivity than ultrasonic waves, and water, bentonite, and bubbles (air) are present in the high-density muddy water A. Even if these are mixed, the attenuation caused by them is not so large, so accurate exploration is possible.

When the inventors of the present invention conducted a test using microwaves with a frequency of 1 Gl-tz and an output of 50 W, and setting the specific gravity of muddy water A to 1.2, very good results were obtained.

In addition, in the embodiment described above, not only the microwave exploration but also the mechanical exploration can be performed by the following method.

That is, the antenna section 18 is moved by the linear drive device 28.
By protruding upward and bringing its upper end surface into contact with the ground 20, the state of the ground 20 in that part can be directly mechanically investigated. Therefore, even if the apparent state of the rock 20 in microwave exploration is normal, pressing the antenna section 18 directly against another rock 20 will show that the rock 20 is truly normal. You can check whether it exists or not. In this case, if the ground 20 is on the verge of collapsing, or on the verge of collapse, the antenna unit 18 driven upward will break down the ground 20 and advance to its upper limit of movement. It's gone. Therefore, if the amount of protrusion is detected by the sensor 44, the state of the ground 20 can be mechanically investigated.

As described above, by exploring the state of the ground 20 using microwaves and mechanical means, extremely reliable exploration information can be reliably obtained. Furthermore, what should be noted in this invention is that, for example,
Even if dirt or the like accumulates on the top surface of the antenna section 18 due to the collapse of the ground, the antenna section 18 is projected upward by the linear drive device 28 and removed from the ground 20.
If the antenna part 18 is rotated by the rotary drive device 30 in this state, the deposits on the top surface of the antenna part 18 will be wiped away from the ground, and microwave exploration will be performed reliably. It is possible to immediately restore the necessary state.

(Effects of the Invention) As described above in detail in the embodiments, the shield collapse exploration device according to the present invention investigates the condition of the ground by emitting and receiving microwaves.
Accurate and reliable information can be obtained without being significantly attenuated by water), gas (air), and solid (bentonite).

[Brief explanation of drawings]

Figure 1 is a sectional view showing the installed state of the device of the present invention, and Figure 2 (
A) is an enlarged view of the main part, FIG. 2(B) is a plan view of the antenna section, and FIG. 3 is a block diagram showing the electrical configuration of the device. 10...Shield ta 14...Face 18.
...Antenna part 18a...Transmission 18t)...Reception 20...Excavation ground 28...Linear drive antenna 30...Single rotation drive antenna Patent applicant Obayashi Corporation Agent
Person Patent Attorney - Kensuke Color Figure 2 (B) Figure 3 Decoy

Claims (1)

[Claims] In shield construction work in which muddy water is supplied to the excavated earth face while excavating, an antenna part for transmitting and receiving microwaves is installed on the upper part of the outer cylinder on the face side of the shield machine, and a transmitter is connected to each antenna part. and a receiver, the receiver receives reflections of microwaves transmitted from the transmitter toward the excavated ground, and collapse is detected based on these signals. Collapse detection equipment for shield construction.