JPS6229599B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an excavation control method and apparatus for a so-called closed mechanical excavator shield machine having a partition wall on the back surface of a cutter.

The earth pressure shield method that uses such a shield machine is to fill the chamber between the cutter and the bulkhead with excavated earth and sand, and apply shield thrust to the face through this excavated earth to stabilize the face. In this method, the excavated earth and sand in the chamber is carried out of the mine by a screw conveyor or other earth removal means while maintaining the face pressure within a predetermined range.

Therefore, in the above-mentioned earth pressure shield method, it is necessary to accurately grasp the filling status of earth and sand in the chamber.

Conventionally, an earth pressure gauge was installed inside the chamber, and the filling status of earth and sand was determined from the measured values of the earth pressure gauge. However, in the case of sandy and gravel ground, the indicated value of the soil pressure meter will vary greatly depending on whether the gravel is in direct contact with the pressure plate or only the sand is in contact with the pressure plate, and there is a risk that measurement will not be possible. Therefore, stable management cannot be performed. Another drawback is that the pressure receiving plate attached to the soil pressure gauge is exposed and is easily damaged.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and device for managing excavation of a shield machine, which eliminates the above-mentioned disadvantages, allows stable management even in sandy and gravelly ground, and reduces wear and tear on the device itself.

However, according to the present invention, the purpose of the lever is to include an injection device for injecting an injection material into a chamber provided on the back side of a cutter of a shielding machine through an injection pipe, a pressure sensor for detecting injection pressure provided in the injection pipe, Introducing the output signal of the pressure sensor for detecting the injection pressure,
The propulsion stroke is controlled by a dynamic strain measuring device that sends an output signal to the operation display panel, and a signal from the sequence circuit according to the display contents of the operation display panel.The rotation speed of the shield propulsion jack and screw conveyor is controlled by the earth pressure. The excavation control device of the shield machine, which consists of a discharge device for excavated earth and sand that is controlled to be within the range of values, is used to monitor the state of earth pressure in the chamber of the shield machine by the injection pressure of a small amount of injection material. This is achieved by controlling the propulsion speed of the shield machine and the amount of earth and sand discharged so that this value falls within a predetermined value range.

According to the present invention, the entire injection material spread over a wide area does not permeate into the excavated soil, and in principle, when inflating a balloon in the soil, the air injection pressure and the earth pressure are almost equal. Similarly, since the pressure is maintained in balance with the ten pressure, the injection pressure of the injection material is almost equal to the earth pressure,
Even in the case of gravel ground, the average value of earth pressure can be obtained as the injection pressure.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is an explanatory diagram showing an embodiment of the present invention. In the figure, 1 is a shield machine, 2 is a cutter provided at the tip of the shield machine 1, and a chamber 3 sealed with a partition wall is on the back of the cutter 2. It is formed.

The tip of a screw conveyor 4 for discharging excavated soil faces the center of the chamber 3, and at the rear of the screw conveyor 4 there is a drive device 6 having a rotation detector 5, and a soil discharge port that opens and closes with an opening/closing jack 7. Install 8.

In addition, an inlet 9' of a steel pipe injection pipe 9 is exposed near the face of the chamber 3, and the injection pipe 9 is connected to an injection device 11 via a solenoid valve 10. Sensor 12 is installed.

On the other hand, a stroke detector 14 and an oil pressure sensor 15 are attached to a shield propulsion jack 13 that propels the shield machine 1. Note that 16 in the figure is a segment.

Next, the injection device 11 will be explained in more detail with reference to FIG. 2. The injection device 11 is composed of a pump tank 17 for injection material and an injection pump 18, which are connected to the injection pipe 9 via electromagnetic valves 19 and 20, respectively. Concatenated.

In addition, it is not desirable for the injection pump 18 to be a blunger-type pump that causes pulsations; instead, it is a pump that does not cause pulsation, is small, can change the discharge amount, and has a fixed-dose pump that does not change much even when the injection pressure fluctuates. pumps (e.g. Mono Pump, Minicleat)
is desirable, and in the illustration, a single-barrel pump consisting of a cylinder 21 and a piston 22 is used, and the piston 22
is connected to the continuously variable speed electric motor 2 via the gearbox 24.
It is attached to a worm rod 23 that moves at 5.

Next, to explain how to use it, the injection device 11
As the injection material to be injected into the chamber 3, it is recommended to use high-concentration bentonite mud (for example, from Yamagata) because the ground has good water permeability in sand and gravel ground.
250# 15% muddy water of bentonite, apparent clay
5,000 cp, etc.) is suitable; on the other hand, fresh water may also be used as the permeability of clay soil is low.

The injection material is previously stored in the stock tank 17, and a small amount is split into the chamber 3 while being controlled by the electromagnetic valves 19, 20, and 10.

The injection material injected from the injection port 9 during shield excavation spreads around the injection port 9' while balancing the earth pressure of the excavated soil filling the chamber 3, and the injection material pressure (internal pressure) and the soil The pressures will be approximately equal. In other words, the injection material is selected to be suitable for the water permeability of the excavated soil and does not penetrate during excavation, so the influence of the earth pressure exerted by the excavated soil on the injection port 9' and the influence of the injection material to counteract this. The injection pressure is almost the same, and the principle is almost the same as when a balloon is placed in sand and sand and inflated while stirring the sand. Stirring prevents stress from concentrating around the balloon.

Strictly speaking, the viscosity of air and water or muddy water is greatly different, so the pressure of the injection material (internal pressure) is different from the injection pressure, but it has been confirmed that there is no problem in practical use.

In addition, even in the case of gravel ground, the influence of the gravel is felt by the entire injected material spread around the injection port 9', making it possible to measure the average earth pressure over a relatively wide range. Unlike the case where the value fluctuates greatly depending on whether or not the gravel hits the pressure receiving plate of the soil pressure gauge due to the influence of pressure, the value fluctuates little.

Managing with such an average value is effective for managing the stability of the face, especially when automating the equipment. Figure 4 shows the earth pressure and the injection pressure of the injection material as a result of changes in the elapsed time in gravel ground. From this figure, it can be confirmed that the injection pressure has little fluctuation and remains at an average value. When controlled by pressure, it is expected that the reaction will be sensitive.

FIG. 3 is a block diagram showing the method of the present invention, showing a pressure sensor 1 for detecting injection pressure provided in an injection arrangement 9.
In step 2, detect the injection pressure that causes splitting of the injection material,
This detection output signal is introduced into the dynamic strain measuring device 26.

The injection pressure that causes splitting at this time is earth pressure + α (α
is a variable related to soil cohesion, shear resistance angle, etc.), and in the case of an earth pressure shield, the earth pressure is expressed as cutter 2
Since the soil is excavated and disturbed by the soil, the influence of α is smaller than the earth pressure, and the relationship of injection pressure = earth pressure holds true.

Therefore, the cutter hydraulic pressure sensor 27 of the cutter hydraulic motor that drives the cutter 2, the screw conveyor hydraulic pressure sensor 28 of the drive device 6 of the screw conveyor 4, and the shield propulsion jack 13.
The detected value of the oil pressure sensor 15 is also introduced into the dynamic strain measuring device 26, and the output signal from the dynamic strain measuring device 26 is introduced into the operation display panel 29. According to the display contents of the display panel 29, the injection pressure of the injection material is determined. The stability of the face can be maintained by controlling the propulsion speed of the shield machine 1 and the rotation speed of the screw conveyor 4 so that the value of is equal to or higher than a predetermined value for maintaining the stability of the face.

In order to prevent the ground from rising, it is also necessary to control the propulsion speed of the shield machine 1 and the rotational speed of the screw conveyor 4 to keep the injection pressure of the injection material below a specific value.

Specifically, output signals from the rotation detector 5 of the screw conveyor 4 and the stroke detector 14 of the shield propulsion jack 13 are introduced into the arithmetic circuit 30,
The calculated value of the calculation circuit 30 is introduced into the operation display panel 29, and this input content is corrected to an appropriate value.
The shield propulsion jack 13 and the screw conveyor 4 may be controlled via the sequence circuit 31 so that the earth pressure is within a predetermined range.

In addition, the contents of the operation display panel 29 are fed back to the injection pump 18 and the solenoid valves 10, 19, 20 of the injection device 11 by output signals and other means.
Operate the injection device 11 without interruption to fill the chamber 3.
It is also conceivable to continue injecting the injection material into the cavity.

As described above, the present invention injects a small amount of injection material into the chamber of a shielding machine using an injection device,
Since the shield machine's excavation control is performed by detecting the injection pressure, stable control can be obtained even in sand and gravel ground, and there is no need to install the detection device itself inside the chamber as in the past, so the device itself There is little wear and tear, and maintenance and inspection are easy.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing an embodiment of the device of the present invention, Fig. 2 is a partially cutaway side view of the injection device portion, and Fig. 3
The figure is a block diagram showing an embodiment of the method of the present invention.
The figure shows the correlation between earth pressure and injection pressure over time. 1... Shield machine, 2... Cutter, 3... Chamber, 4... Screw conveyor, 5... Rotation detector, 6... Drive device, 7... Opening/closing jack, 8... Sediment discharge port, 9 ...Injection piping, 9'
... Inlet, 10 ... Solenoid valve, 11 ... Injection device, 12 ... Pressure sensor, 13 ... Shield propulsion jack, 14 ... Stroke detector, 15 ...
...Oil pressure sensor, 16...Segment, 17...
Stock tank, 18...Infusion pump, 19,2
0... Solenoid valve, 21... Cylinder, 22... Piston, 23... Rod, 24... Gearbox, 25... Electric motor, 26... Dynamic strain measuring instrument, 27
... cutter oil pressure sensor, 28 ... conveyor oil pressure sensor, 29 ... operation display panel, 30 ... calculation circuit, 31 ... sequence circuit.

Claims (1)

[Claims] 1. The state of earth pressure in the chamber of the shield machine is detected by the injection pressure of a small amount of injection material, and the excavation speed of the shield machine and the earth and sand are adjusted so that this value is within a predetermined value range. A shield machine excavation management method characterized by controlling the amount of discharge. 2. An injection device that injects the injection material into the chamber provided on the back of the cutter of the shield machine through an injection pipe, a pressure sensor for detecting injection pressure provided in the injection pipe, and an output signal from the pressure sensor for detecting the injection pressure. Introducing a dynamic strain measuring device that sends output signals to the operation display panel, and the rotation speed of the shield propulsion jack and screw conveyor whose propulsion stroke is controlled by signals from the sequence circuit according to the display contents of the operation display panel. An excavation control device for a shield machine, which includes an excavated earth discharge device that controls the earth pressure to be within a predetermined value range.