JPS6349036B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shield excavator having a device for pumping an appropriate amount of air bubbles into a chamber facing the face of an earth pressure type excavator using a shield.

Conventionally, when excavating a water-logged sandy soil layer (including a gravel layer) with a shield excavator, the stability of the face is maintained by filling the chamber of the excavator with excavated soil. However, when the chamber is filled with earth and sand that has a large internal friction angle, the rotational resistance of the excavator's cutter increases, and in some cases, the cutter becomes unable to rotate or becomes extremely slow, resulting in a significant reduction in excavation speed. There was a problem.

One way to reduce this resistance is to inject slurry (a mixture of water and clay minerals such as bentonite and clay) into the chamber and mix it with the excavated soil, turning the excavated soil into a slurry. Conventionally, a method has been used to reduce the rotational resistance of the cutter, but since the muddy mixed soil produced by this method is treated as industrial waste, there has been a problem in that it is difficult to dispose of it.

The present invention was made to solve the above-mentioned problems, and by press-fitting air bubbles into the chamber of the face of a shield excavation machine and mixing it with the excavated soil, the shear of the mixed soil is reduced, and the cutter is This reduces rotational resistance.

According to experimental results, when masa soil (coarse sand) and air bubbles are mixed at a volume ratio of 1:0.25, masa soil with a slump of 18 cm has such fluidity that it becomes impossible to measure the slump before mixing. I found out. Thus, the mixing of air bubbles significantly reduces the shear resistance of the soil.

Furthermore, if mixed soil containing air bubbles is transported to a soil dump and left there, the air bubbles will naturally disappear and the soil will return to the state of normal excavated soil, so there is no need to treat it as industrial waste. Therefore, it is very effective in terms of pollution control.

As described above, the present invention provides a shield excavation device that reduces the rotational resistance of the cutter in the chamber of the face of the shield excavation machine, and is also advantageous in terms of pollution control, since there is no need to treat excavated soil as industrial waste. The purpose is to

Embodiments of the present invention will be described below with reference to the drawings.
In the figure, 1 is the ground, 1a is the shaft, 2 (see Figure 1) is the shield excavator, 2' (see Figure 2) is the shield excavator for propulsion, 3 is the chamber facing the face, and 4 is the screw discharger. The earth machine, 5 (see Figure 1) is a segment, 6 (see Figure 2) is a propulsion pipe, and 7 is a propulsion jack, which in the case of Figure 1 is interposed between the front end of the excavator 2 and segment 5. In the case of FIG. 2, the propulsion pipes 6 are arranged to be connected to the rear of the excavator 2' and are arranged so as to propel the rear end portions in the shaft 1a. Further, 8 is an earth removal conveyor installed in connection with the screw type earth removal machine 4.

Reference numeral 9 denotes a foaming device, which in the case of FIG. 1 is installed in the shaft 1a, and in the case of FIG. 2 it is installed on the ground 1.
FIG. 3 shows a schematic diagram of the structure of this foaming device 9, in which 10 is a foaming tube. An air supply pipe 11 and a liquid supply pipe 12 are connected to the foaming tube 10, and the air supply pipe 11 has a pressure regulating valve 13 and a flow rate control valve 14.
is inserted. 14a is a valve adjustment lever of the flow rate control valve 14.

Further, the liquid sending pipe 12 has a variable pump 16 which sucks the foaming liquid from the foaming liquid tank 15 and sends it to the foaming pipe 10.
A check valve 17 is inserted. 16a is a flow rate adjustment lever of the variable pump 16, 18 is an electric cylinder that controls this lever 16a, and 18' is an electric cylinder that controls the valve adjustment lever 14a. Reference numeral 19 denotes a foam pipe having one end connected to the foam tube 10, and the other end connected to the inside of the chamber 3 of the face of the excavator.

Further, 20 is a displacement detector of the digging jack 7, and 21 is a conductor for introducing the output signal of this displacement detector 20 to the control section 22.

FIG. 4 is a circuit block diagram showing an example of this control section 22, where 23 is a rotary encoder, 24 is a rotary encoder, and 24 is a rotary encoder;
25 is a clock, 26 is a D/A converter, 27 is a controller, 28 is an electric cylinder power supply, 29 is a potentiometer, and 30 is a controller.

That is, the apparatus of the present invention is constructed so that the amount of bubbles forced into the chamber 3 of the face from the foaming device 9 can be appropriately controlled depending on the digging speed of the shield tunneling machines 2, 2'.

As the foaming liquid to be used in the tank 15, a surfactant or a protein-based foaming agent is suitable. ), or Escort K whose main component is partially hydrolyzed protein
(product name) etc.

Next, the operation of the apparatus of the present invention constructed as described above will be explained. During excavation, the device of the present invention drives the variable pump 16 to feed the foaming liquid in the tank 15 into the foaming tube 10, and at the same time blows air through the air pipe 11 to foam the foamed foam. pipe 19
It is fed into the chamber 3 of the face of the excavator 2, 2'. In this way, the excavated soil in the chamber 3 of the face becomes more fluid due to the inclusion of bubbles and the rotation of the cutter, so that the rotational resistance of the cutter can be reduced and the excavation performance can be improved.
The excavated earth and sand mixed with air bubbles is discharged from the screw-type earth remover 4 onto the conveyor 8, and is carried outside via the conveyor 8, but if this air mixed earth and sand is left in the soil dumping site, the air bubbles will naturally form. Since the excavated soil disappears and becomes similar to ordinary excavated soil, there is no risk of it becoming a problem in terms of pollution control.

Furthermore, in the apparatus of the present invention, the amount of the bubbles to be pumped is appropriately controlled in accordance with the digging speed of the excavators 2, 2'.

That is, the displacement detector 20 detects the displacement caused by the propulsion jack 7, and when the signal output is input to the rotary encoder 23 via the conductor 21, it is converted into a pulse, and the pulse is sent to the pulse counter 24.
The number of pulses per unit time by the clock 25 is D/A converted by the D/A converter 26, and this analog signal is sent to the controller 27.
sent to. The controller 27 controls the amount of bubbles generated by the foaming device 9 by controlling the electric cylinder power source 28 and operating the adjustment levers 14a, 16a via the electric cylinders 18, 18'.

In this case, the movement of the electric cylinders 18, 18' is controlled by reversing the power supply to the tensiometer 29 and passing the electric cylinder power supply 2 through the controller 30.
By setting it to 8, it is possible to make adjustments proportional to the speed.

Since the device of the present invention is as described above, this device reduces the rotational resistance of the cutter in the chamber of the face of the shield excavation machine to improve excavation performance, and also makes it possible to reduce the need for handling excavated soil as industrial waste. By eliminating this, an excellent effect can be obtained, which is extremely advantageous in terms of pollution control.

[Brief explanation of the drawing]

1 and 2 are vertical sectional views showing the state of ground excavation by the shield drilling device of the present invention, FIG. 3 is a schematic diagram of the configuration of the foaming device, and FIG. 4 is a circuit block diagram showing an example of the control section. . 1...Ground, 1a...Shaft, 2...Shield excavator,
2'...Propulsion shield tunneling machine, 3...Chamber,
4... Screw earth removal machine, 5... Segment, 6... Propulsion pipe, 7... Propulsion jack, 8... Soil removal conveyor, 9... Foaming device, 10... Foaming tube, 11... Air feed pipe, 12... Liquid feed pipe, 13 ...Pressure adjustment valve, 14...Flow rate control valve, 14a...Valve adjustment lever, 15...Foaming liquid tank, 16...Variable pump, 16a...Flow rate adjustment lever, 17...Check valve, 18, 18'...Electric cylinder, 19... Foaming pipe, 20...Displacement detector, 2
DESCRIPTION OF SYMBOLS 1...Conducting wire, 22...Controller, 23...Rotary encoder, 24...Pulse counter, 25...Clock, 26...D/A converter, 27...Controller, 28
...Electric cylinder power supply, 29...Potentiometer, 30...Controller.

Claims (1)

[Claims] 1 A foaming device is attached to the shield tunneling machine, and the bubbles generated by the foaming device are press-fitted into the chamber of the face of the shield tunneling machine, and a displacement detector is installed on the propulsion jack of the shield tunneling machine, and this A shield drilling device characterized in that the foaming device is controlled by an output signal from a displacement detector.