JPS59213896A - Shield drilling construction method - 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] The present invention relates to a shield excavation method in which excavation is carried out while pumping excess air bubbles into the front face of a Tonosho type excavator using a shield and into a chamber facing the face. .

Conventionally, when a shield excavator excavates a sandy soil layer (including a sandy gravel layer) with stagnant water, the stability of the face is maintained by filling the chamber of the excavator with excavated soil. However, in reality, it is very harsh to create a condition in which the chamber is filled with excavated soil, and it is also difficult to prevent groundwater from flowing into the chamber, so the stability of the face is less than 11 tons. I'm in a bad state. In addition, if the chamber is filled with earth and sand with a large internal 1γ friction angle, the rotational resistance of the cutter of the excavation machine will increase, and in some cases, the rotation of the cutter will become impossible or extremely slow, resulting in slower excavation speed. There was a problem with the drop.

As a method to prevent groundwater from flowing into the chamber and to reduce the resistance force of cutter rotation, mud sludge t, J (
By injecting a mixture of water and clay minerals such as bentonite and clay into the chamber and mixing it with the excavated soil, the excavated soil becomes muddy and prevents groundwater from flowing into the chamber. Conventional methods have been used to reduce the rotational resistance of the chamber, but if the water pressure at the face is high or if there is a water retention layer made up of cobbles, it is impossible to separate the water and the flow into the chamber is reduced. It may not be possible to prevent groundwater from flowing into the ground. Also, the muddy mixed soil obtained by this method is (〕1
” is high and muddy, so disposal requires office work.
Disposal is causing secondary construction pollution.

The present invention was made to solve the above-mentioned problems.
Air bubbles that do not disappear even when exposed to water are sent to the front of the cutter of the shield excavator, and the air bubbles penetrate into the ground, creating a pressurized air condition that is more effective than the normal pressurized air construction method and preventing groundwater from flowing into the face. In addition to stabilizing the face, air bubbles are also injected into the chamber through a separate system to mix it with the excavated soil, reducing the shear force of the mixed soil and reducing the rotational resistance of the cutter. By filling the chamber and screw, the face is further stabilized, and the excavated soil has good water permeability and low air permeability.

According to experimental results, when foam material is used on ground with a sand and gravel content of 82%, the amount of air used in the normal pressure air construction method is approximately 100%
It had a sufficient pressure effect even when used for 1/0 of a bubble.

In addition, the volume ratio of masa soil (coarse sand) and air bubbles is 1:0.
．． It was found that when mixed at a ratio of 25%, masa soil with a slump of 7 CIll had such fluidity that it was impossible to measure the slump before mixing. In this way, the mixing of air bubbles significantly reduces the soil shedding/sheathing resistance.

In addition, if mixed soil containing air and bubbles is transported to a soil dump and left unattended, the air bubbles will naturally disappear and return to the state of normal excavated soil, resulting in secondary construction pollution due to construction abandonment. It has the advantage of not having to worry about

As mentioned above, the present invention aims to stabilize the face by sending air bubbles that are resistant to water to the front of the cutter of the shield excavator to create a pressure air condition that is more effective than the normal pressure air construction method. By sending air bubbles that are resistant to water to reduce the rotational resistance of the cutter in the chamber, and filling the chamber and screw with this mixed soil, we aim for further stability of the face and create a water-resistant surface on the excavation. As a pollution control measure, it provides low air permeability and there is no risk of secondary construction pollution even if the excavated soil is disposed of.
The purpose of the present invention is to provide a shield excavation method that is advantageous to the public.

A detailed description of the invention will be given below with reference to the drawings.

In the figure, 1 is the ground, 1a is a shaft, 2 (see Figure 1) is a shield tunneling machine, 2' (see Figure 12) is a propulsion shield tunneling machine, 3 is a face, 4 is a chamber facing the face,
5 is a screw earth remover, 6 (see Figure 1) is a segment, 7 (see Figure 2) is a propulsion pipe, 8 is a propulsion jack,
In the case of Fig. 1, the propulsion pipes 7 are installed between the front ends of the excavator 2 and the legentro, and in the case of Fig. 2, the rear end in the shaft 1a of the propulsion pipes 7 is connected and arranged to the rear of the excavator 2'. It is arranged to promote the division. Further, 9 is an earth removal conveyor installed in connection with the screw set earth removal Ia5.

10 is a foaming device, which in the case of FIG. 1 is installed in the shaft 1a,
In the case of Figure 2, it is installed on the ground 1.

Depending on the space, it can also be installed inside the tunnel 11. Bubbles are sent to the foaming device 10 by a foaming vibrator 12, and this pipe 12 is branched into a face injection vibe 13 and an in-chamber injection vibe 14, each of which has an ore control valve 15, 15' inserted. A face bubble pressure detector 16 is attached to the pipe 13. A cutter is attached to shield excavation 12.2'. 19
is a displacement detector of the propulsion jack 8.

FIG. 3 does not show the control system diagram of the foaming device 10, and the microcomputer 20 controls the amount of air bubbles, the opening degree of the gate 5a of the screw set masonry machine 5, and the screws 5b (1st.
(see Figure 2). 21 is a block having a statistical processing function for each data input to the microcomputer 20, 22 is an amplifier C for the signal of the face bubble pressure P from the face bubble detector 16, and 23 is a tank for bubble liquid.

FIG. 4 is a circuit block diagram showing an example of the foaming mechanism of the foaming device 10, and 20 is the microcomputer 124 that converts each signal from an analog signal to a digital signal.
D converter 25 is a D/A converter that converts the digital signal output from the microcomputer into an analog signal, 26.
Reference numeral 26' indicates an electronic continuously variable speed control plate, 27.27' indicates a synchronous rotation proportional control motor, and 28.28' indicates a clutch brake, which is a brake device U for limiting the upper and lower limits of the face bubble pressure P. 29 is acceptable. 32 is a compressor, and the air from the compressor 32 is sent to the foaming tube 34 via the air supply pipe 33, where it is mixed with the foam liquid to create air bubbles, and the air bubbles are sent into the mine via the foam pipe 12. Sent.

・In the construction method of the present invention, the above-mentioned device is used to pump air bubbles into the face and chamber at the front of the shield excavation machine, and control the face bubble pressure, cutter pressure, screw earth removal pressure, and excavation progress during shield excavation. The detected speed values are sequentially sent to the microcomputer 20, which statistically analyzes them, and based on the analysis results, controls the amount of air bubbles injected into the front surface of the cutter and into the chiton bar. At the same time, the rotation speed and opening degree of the screw earth discharge pressure 5 are also controlled,
In addition to keeping the face bubble pressure constant, the rotational resistance of the cutter is also moderated to create the optimum digging condition.

The foaming liquid used in the tank 23 is suitably a surfactant with a superabsorbent polymer added thereto, or a protein-based foaming agent, such as polyoxyethylene alkyltubonol. : Conis whose main component is r-methyl sodium sulfate] -1-L (trade name) is a super absorbent polymer, for example, Sumikagel (trade name) whose main component is a vinyl aljyl acrylic M salt copolymer. (, i, 31; 1) There are products with the addition of Aqua Keep (trade name) whose main ingredient is sodium acrylate, and Niskort K (trade name) whose main ingredient is partially hydrolyzed protein. .

Next, an embodiment of the method of the present invention using the apparatus constructed as described above will be explained. This invention construction method [When excavating, variable pump 2
At the same time, the foaming liquid in the tank 23 is sent to the foaming pipe 34 by the combrella 1ner 32.
Air is sent into the foaming tube 34 through the foaming tube 34 and foamed, and the foamed strong air bubbles are sent to the eve 12 to the drilling machine 2.
It is sent into the face 3 in front of the cutter of C2' and into the chamber 4. In this way, a more effective air pressure condition than the normal air pressure method is created, and the face 3 can be stabilized. In addition, it is possible to reduce the rotational resistance of the cutter in the chamber 4, and by filling the chamber 4 and the screw earth remover 5 with this mixture, it is possible to further stabilize the plowing blade 3. It is possible to impart a state of low air permeability to excavated soil. Furthermore, if this air bubble mixed soil is left in a soil dumping site, the air bubbles will naturally disappear and it will become similar to ordinary excavated soil, so there is no risk of it becoming a problem in terms of pollution control.

In addition, in the construction method of the present invention, data on the face bubble pressure, cutter pressure, screw earth removal pressure, and excavation speed of the shield excavation 118 are collected by the microcomputer 20 at any time, statistically analyzed, and the analysis results are Based on this, the amount of bubbles injected into the face 3 on the front of the cutter and the amount of bubbles injected into the chamber 4 is controlled, and the number of revolutions and the volume of the screw earth remover 5 are controlled to keep the bubble pressure at the face constant. In addition to maintaining the rotational resistance of the cutter, it is also 31! ! degree,
It can be controlled to create optimal digging conditions.

That is, each pressure is detected by the face bubble pressure detector 16, cutter pressure detector 17, and screw discharge pressure detector 18, and the displacement due to the propulsion jack 8 is detected by the displacement detector 19. The output signal is converted to Δ/ by the A'/D converter 24.
Convert it into D and send it to the microcomputer-20.
These data are analyzed in a unified manner, and based on the analysis results, an optimal control signal is sent to the electronic variable speed control panel 26, 26' via the micro combi coater 20, and the synchronous rotation is performed. By controlling the discharge m of the variable pump 29 by changing the rotation speed of the proportional control Tanabata 27.27', and also controlling the amount of air from the compressor 32, the amount of bubbles generated from the foaming tube 34 and the bubble liquid can be controlled. It is possible to adjust the mixing ratio to the optimum value by changing the mixing ratio of the amount of air.

Further, the bubbles sent from the foaming pipe 34 through the foaming pipe 12 are divided into the injection face injection pipe 13 and the injection pipe 14 into the chamber 4, and each flow (6) control valve 15.15'
By controlling this with a microcomputer 20, the amount of bubbles can be adjusted, the face bubble pressure can be kept constant, and the rotational resistance of the cutter can be controlled. Furthermore, in order to make these adjustments more precise, the rotational speed and opening degree of the screws 1 and 11 can also be controlled to create an optimal digging condition.

As described above, the construction method of the present invention creates a more effective wet air condition than the normal pressure construction method, stabilizes the face, and reduces the rotational resistance of the cutter in the dam. This has the effect of improving excavation performance, filling the chamber and screw with mixed soil, and further stabilizing the face. In addition, it is possible to impart tU air permeability to the excavated soil, and since this excavated soil does not need to be treated with industrial waste, the method of the present invention has the excellent effect of being extremely advantageous in terms of pollution control. is obtained.

[Brief explanation of the drawing]

Figures 1 and 2 are elevational views showing the state of ground excavation by the method of the present invention, Figure 3 is a schematic diagram showing the control system of the foaming equipment, and Figure 4 is a schematic diagram showing the configuration of the foaming equipment. be. 1...Ground 1a...Shaft 2...Shield excavation (2'...Propulsion shield excavation machine 3...Face surface 4...Chamber 5...
・Screw earth removal machine 6...Legment 7...Propulsion pipe 8...Propulsion jack 9...1 conveyor for soil removal 10...Foaming device 11...1 to tunnel underground 12...Transmission Foam vibrator 13... Face injection pipe 14... Injection vibe in the chamber 15... Flow rate control valve (face side) 15'... Flow rate control valve (inside the vetylene bar) 1G... Face bubble pressure detector 17. ...Cutter pressure detector 18...Screw discharge pressure detector 19...Displacement detector 20...Microcomputer 21...Block 22 with day/evening processing functions...
・Amplifier 23...Bubble liquid tank 24...
A/D converter 25...D/Δ converter 2'6...
Electronic variable speed control 1! (Bubble liquid amount) 26' Electronic variable speed control panel (Air amount) 21... Synchronous rotation proportional control motor (Bubble liquid amount) 27' Synchronous rotation ratio 7 Control motor (Air amount) 28... Clutch brake ( Bubble liquid amount) 28' ・
...Clutch brake (air side) 29...Variable pump 30...Liquid feed pipe 31...Check valve 3
2... Compressor 33... Air pipe 3
4... Foaming pipe 35... Foaming pipe. Patent applicant Aoki Construction Co., Ltd.

Claims (1)

[Claims] 1. To maintain the stability of the face by force-feeding excess air bubbles to the face at the front of the shield excavation machine. A shield excavation method characterized by mixing with.