JPH02289792A - Earth pressure shield construction method - Google Patents

Abstract

PURPOSE:To improve soil with a small-diameter machine by adding a mud improving agent to the sediment mixed with an excavation adding agent in a conveying screw conveyor, improve mud into good-quality sediment during conveyance, and carrying it out. CONSTITUTION:An excavation adding agent mixed with a fluidity/viscosity improving agent of excavated soil and a mud improving main agent is filled into the natural ground in front of the cutter head 2 of a shield excavator 1 by a filling pipe 1c. An excavation adding agent is mixed with sediment via a mixing chamber 1b and a screw conveyor 3. A mud improving auxiliary agent is added into the discharged soil screw conveyor 3, the seal covered with the improving main agent is chemically released to obtain good-quality sediment, which is then discharged through a hopper 13. Discharged soil can be improved without providing a special mixing mechanism.

Description

[Detailed Description of the Invention] (Field of Industrial Application) This invention relates to a shield construction method in which excavated soil is improved and the improved soil is used to excavate while counteracting the pressure of other mountains. Suitable for use in shield construction methods.

(Conventional technology) In the conventional general earth pressure shield, excavation additives are added to the excavated soil to give it fluidity and viscosity. There were the following problems. fat There is a lot of groundwater in the ground. When groundwater pressure is high, excavated earth and sand are ejected together with pressurized water from the outlet of the earth removal screw conveyor, greatly disturbing the ground around the face of the shield machine, and causing ground surface subsidence and collapse accidents. was.

tb+ The discharged sediment is. Since it is highly mobile and difficult to transport outside the site using dump trucks, etc., it is necessary to make improvements to eliminate fluidity within the shield site. (Problem to be solved by the invention) In order to prevent the above-mentioned eruption of discharged soil, the discharge port is equipped with a port-tally valve, etc. to minimize face pressure fluctuations. When water pressure of 2 to 3 kg/cd is applied, earth pressure shielding cannot be used because it is impossible to excavate, and another shielding method such as the mud water pressure shielding method must be used. When improving drained soil with high fluidity, a soft mud soil improver is added and mixed with the drained soil at the medical field site to eliminate fluidity. The purpose of this invention is to solve the above-mentioned problems such as ``the discharged soil erupts together with the pressure water of the ground'' and ``the discharged soil cannot be transported outside the site unless it is improved.'' do. (Means and effects for solving the problem) This invention aims to achieve the above object. A drilling additive consisting of a mixture of a material for improving the fluidity and viscosity of excavated soil and a main agent for improving mud is added to the excavated soil at the face and mixing chamber during shield excavation, and in the earth and sand discharge screw conveyor to improve the excavated soil and the main agent for improving mud. After thoroughly mixing the materials, a mud improvement agent is added to the soil discharge screw conveyor, and the soil is improved to high quality soil in the soil discharge screw conveyor before being carried out. This allows for sufficient soil mixing and improvement even when using a small-diameter shield machine.

(Example) An example of this invention will be described in detail with reference to the drawings. Referring to Fig. 1 fat and Fig. 1 mountain), l is the main body of the earth pressure shield machine. To the front cassock, hen night from Do 2.
While discharging a fluidity and viscosity improving material called an excavation additive made of clay, water, etc., the canter head 2 is rotated to cut off and excavate other mountains. The excavated soil is taken into the mixing chamber Ib, and the excavated soil is mixed with the above-mentioned excavation additive injected from the excavation additive injection pipe to plastically fluidize the soil. The above drilling additives are made at a working base outside the shield mine. Bonp P. It is conveyed through the shield mine by piping 4 and is injected into the ground by the canter 2 of the shielding machine 1 through the injection pipe [C] communicating with the piping 4, and mixed in the mixing chamber tb as described above. On the other hand, in the conveying pipe 4 for this excavation additive material, a slurry of the mud improving agent is mixed according to the excavation speed of the shield machine, that is, excavation ±11, and the excavated soil quality, and is injected into the face. Combine them in the mixing chamber 1b and uniformly disperse the 5 mud improvement main ingredients into the excavated soil. The main agent for improving mud is made into a slurry by mixing the main agent and water outside the shield pit or behind the shield [1], and P indicates its injection pump. When injecting the mud improving agent into the face, it can be added using the drilling additive injection pipe 1c connected to the pipe 4 as shown in the figure, or by using the shield machine 1.
A special injection tube is provided for the. Independently on the face? You may add it. The above injection bomb e! detects the digging speed of the shield machine l and adjusts the discharge amount of the bomb. It has an adjustment device (not shown) that can inject excavated soil at the appropriate ratio. The main mud improvement agent consists of agents that work to improve the soil quality by mixing with the mud (for example, flocculants whose main ingredients are natural plant products such as Elfresh (trade name)). A chemical seal is placed on the surface to prevent it from dissolving in water.

In this way, the excavated soil is mixed with excavation additives in the mixing chamber 1b, and becomes mud with high fluidity and stickiness. This mud is pulled out backwards by a screw conveyor 3 for wandering soil. The screw conveyor 3 for earth removal is
The first conveying screw 3l, which is arranged in a straight line through the chassis 14, and the second conveying screw 32 are located above the chassis 14. And the first and second W! Feeding screw 3+. Mixing screw 3 that runs between 3 tons,
It depends. The above-mentioned IR feed screw 31 is housed in a cylindrical case 3a whose tip opens into the shield chamber lb, and the upper part of the case 3a communicates with the mud improvement aid injection pipe 5 behind the partition wall 1a. A hole is formed. This mud improvement agent has the function of chemically removing the seal of the mud improvement main agent, and by adding this mud improvement agent from the injection hole 5 in an appropriate ratio according to the conveyance amount of the screw conveyor. By mixing it with mud in the screw conveyor 3, it is possible to improve the mud into good quality soil with no fluidity.

For the above mixing, when the screw conveyor is a ribbon screw, the mixing degree is adjusted by changing the position of the auxiliary agent injection hole as shown in Figure 2, and when the screw conveyor is a shafted screw. An auxiliary mixing screw may also be provided for mixing.

In addition, the shutter 14 has opening/closing cylinders 14 provided on both sides.
A shirt that opens and closes in the vertical direction by b? 14a, and by keeping this shutter plate 14a closed. The earth and sand conveyed by the 1111th feeding screw 3 is blocked by the shutter plate 14a and flows into the mixing screw 3 from below.

The above-mentioned mixing screw 3 promotes solidification by mixing the soil conditioner with the soil that could not be solidified sufficiently by the first conveying screw 31, as the soil that has been excavated and turned into soft mud has high fluidity. At the same time, it consolidates the earth and sand to form a plug zone. A mixing screw 33 is rotationally driven by a drive motor 8 provided at the rear end of the case 3b via a deceleration a9, and a bragdun is formed in the case 3b by an action described later.

On the other hand, the soil that has been thoroughly mixed with the soil conditioner and solidified by the mixing screw 33 is. 2nd R feeding screw 3
■It is designed to be sent into case 3c. Is the second conveyance screw 32 on the rear end side of the case 3c? It is designed to be rotated once by a drive motor 10 provided through a speed reducer l1, and conveys the solidified earth and sand to the rear of the case 3c, and a shunter l2 is provided at the rear end of the case 3c. ing. The shutter 12 has a shutter plate 12a that opens and closes in the vertical direction by an opening and closing cylinder 12b. In addition, a hopper 13 is provided protruding from the rear side of the shaft 12, and when the second transport screw 3■ opens the shaft 12, the earth and sand are transferred to a transport vehicle such as a trolley or an earth removal vehicle via the shaft 13. The objects are dropped onto transport means such as conveyor belts, and transported backwards by these transport means. FIG. 3 shows a block diagram for performing the above measurement control, including a shield jack stroke sensor 21, a shield jack speed sensor 22, a screw conveyor rotation speed detector 23, a screw conveyor torque detector 24,
Discharged soil flow velocity detector 25, discharged soil density detector 26, excavation additive addition amount measuring device 27, improved main agent addition amount measuring device 28
, the input signal from the improved auxiliary agent addition amount measuring device 29 is input to the controller 30, and the data is exchanged with the memory 1J31 to determine the appropriate addition amount 132 of the base agent and addition amount 33 of the auxiliary agent. ．． In addition, measurements are made to determine whether or not the above-mentioned improvement of the excavated mud and the formation of water-stopping mud are being carried out in the screw conveyor, and the amounts of the mud improvement main agent and mud improvement aid are adjusted. Measure the amount of soil removed. It is also determined whether the cutting face is causing excessive excavation and disturbing the surrounding ground.

Therefore, according to the embodiment of the present invention, the mud and the main mud improving agent are sufficiently mixed in the canter chamber, and the improving main agent is chemically sealed with the mud improving agent in the screw container. By doing so, the desired mixing improvement can be achieved using a shield machine with a small diameter without adding a special mixing mechanism.

(Effects of the Invention) As described in detail above, the present invention uses an excavation additive material which is a mixture of an agent for improving the fluidity and viscosity of excavated soil and a main agent for improving mud. It is added to the excavated soil in the screw conveyor to thoroughly mix the excavated soil and the mud improvement agent, and then the seal covering the improvement agent is chemically removed by the mud improvement agent added in the earth and sand conveying screw conveyor. By doing so, it is possible to improve the quality of the soil in the soil removal screw conveyor. Even without a special mixing mechanism,
Sufficient mixing and soil improvement can be achieved using a small-diameter shield machine.

Furthermore, according to the present invention, the mud improvement main agent and the improvement aid are continuously mixed and improved, and at the same time, a water stop plug zone is formed to counter the water pressure acting from the front part of the shield in the soil removal screw conveyor. This prevents soil from blowing up. It prevents the face from collapsing, does not disturb other surrounding mountains, and can be easily discharged.

[Brief explanation of the drawing]

Fig. 1(a) is a sectional view showing an embodiment of a shield excavator using the earth pressure shield construction method of the present invention, and Fig. 1(b)
l is an explanatory diagram of FIG. 1 (al). FIG. 2 is an explanatory diagram of another embodiment, and FIG. 3 is a block diagram for performing the measurement system 13'Il. l... Shield machine main body 1b...・Mixing chamber Ic...Injection pipe, 2...Cantahesod P+.Pz...Injection pump 3...Screw conveyor for soil removal 4...Piping, 5...Auxiliary agent injection pipe.Patent applicant Representative of Konoike Gumi Co., Ltd. (and other names)
Person (Patent Attorney) Osamu Matsuzawa■ Figure Procedural Amendment dated April 6, 1990, I1, Office Commissioner Fumiyoshi Yoshida, Incident Indication, 1999 Patent Application No. 107402, 2. Name of the invention Earth pressure system shield construction method 3. Relationship with the case of the person making the amendment

Claims (2)

[Claims] (1) An excavation additive consisting of a material that improves the fluidity and viscosity of excavated soil and a main mud improving agent is added to the excavated soil during shield excavation, in the face and mixing chamber, and in the earth and sand transport screw conveyor. The soil improvement agent is sufficiently mixed, and then a mud improvement agent is added to the earth and sand transporting screw conveyor, and the seal covering the improvement agent is chemically removed by the soil improvement agent, thereby making the earth and sand transporting screw conveyor possible. This is an earth pressure shield construction method that is characterized by improving the soil into high-quality soil and transporting it. (2) Claim (1), wherein the main mud improvement agent and the mud improvement aid are mixed and improved in a screw conveyor for carrying out earth and sand, and a water stop plug zone is formed to counter the water pressure acting from the front surface of the shield. Earth pressure shield construction method described.