JPH0332676B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shield construction method that uses both high concentration muddy water and low concentration muddy water.

The main elements that make up the shield method include excavation, face stabilization, soil removal, lining, and surveying. Various construction methods can be considered depending on how each of these elements is implemented and how they are combined. In recent years, research and development of shield construction methods has focused on the elements of face stability and soil removal due to social and economic demands. On the other hand, it has become essential to apply the shield method to congested ground such as clay, sand, and gravel. Various construction methods have been developed under these circumstances, but the current situation is that a shield construction method that is sufficient to be applied to the above-mentioned ground has not yet been developed.

Conventional construction methods are broadly divided into mud pressurization method and mud pressurization method, but mud water pressurization method supplies muddy water mixed with bennite etc. into the compartment of the shield face part through a pipe installed inside the tunnel. This system circulates the mud through the shaft, compartment, and shaft while pressurizing it, forming a muddy film on the face, making it an impermeable film, and stabilizing the face by applying muddy water pressure to the face. . However, this construction method has the dual functions of suppressing the face with muddy water and discharging excavated soil through pipes. For example, it is necessary to increase the concentration of muddy water in sandy or gravelly ground. On the other hand, a contradiction arises in that it is desirable for the muddy water concentration to be low for pipe transportation. In addition, with a shield machine with a full-section cutter plate, the mud water only acts on the ground through the slits in the cutter plate, so the ground is directly cut by the cutter, and the mud water pressure cannot be effectively applied to the face. There is.

In addition, the mud construction method is a construction method that stabilizes the face by filling the compartment in front of the bulkhead of the shield machine with excavated soil, and also prevents groundwater from flowing out by making the excavated soil viscous. However, soil discharge is mainly carried out using trolleys (transport vehicles), which are unsuitable for cases where long-distance transportation of discharged soil is required or for tunnel construction with small diameter cross sections. The pressure measurement in the upper compartment is insufficient compared to the mud water pressure measurement in the mud water construction method, and furthermore, there are drawbacks such as a large amount of power being required to rotate the cutter.

The present invention was made with the aim of improving the drawbacks of the conventional shield construction method described above, and it is possible to effectively apply mud water pressure to the face, facilitate soil separation, and enable small-volume drainage. The present invention provides a shield construction method that achieves long-distance transportation of discharged sediment using a mud pump.

The present invention will be explained below based on the attached embodiment drawings. Figure 1 is an operational diagram of the shield construction method according to the present invention, Figure 2 is a front view of the cutter part, and Figure 3 is a side view. 1
2 represents the shield machine, 2 represents the lining, 3 represents the propulsion jack that propels the shield machine using the covering soil 2 as a reaction force receiver, 4 represents the ground, and 5 represents the shaft. 6 is a bulkhead provided in the shield machine 1, 7 is a bulkhead 6
This cutter plate 7 is a fully closed type cutter plate that cuts the ground 4 with a rotating shaft 8 passing through the center of the shield machine 1.
A compartment 26 is provided between the back surface of the partition wall 6 and the front surface of the partition wall 6. Also, this cutter plate 7 has a slit 9.
A cutter tooth 10 is fixed to the rear side of the cutter plate 7 so as to protrude from the front side of the cutter plate 7, and a cutter tooth 10 is fixed to the rear side of the cutter plate 7 by being operated by a jack 11 to open the slit 9. A gate 12 is provided for adjusting the degree. Reference numeral 13 denotes a mud pipe that transports highly concentrated muddy water mixed with materials such as bentonite that clogs the gaps between soil and sand from a tank 14 on the ground to the shaft 5, the middle of the soil covering 2, and the center of the rotating shaft 8. It is then supplied to a pipe 16 arranged on the back side of the cutter plate 7. The pipe 16 is fixedly attached to the back surface of the cutter plate 7 at the rear of the cutter tooth 10 in the rotational direction,
A discharge hole 17 passing through the cutter plate 7 from the pipe 16
Mud water is discharged onto the face surface 18 through the cutter plate 7, and is ejected into the space 19 behind the cutter teeth 10, which is created when the ground 4 is cut by the cutter teeth 10 protruding from the front side of the cutter plate 7. . It is preferable that the holes 17 are elongated holes extending in the radial direction of the cutter plate 7, and instead of the holes 17, or in addition to the holes 17, an appropriate number of through holes 20, 20 may be bored, and muddy water may be discharged from the through holes 20, 20 through the pipe 16. 21 is a center cutting tooth provided at the center position of the cutter disk.

Reference numerals 22 and 23 in FIG. 1 are a water pipe and a sludge pipe, and in this embodiment, the water pipe 22 is connected to the vertical shaft 5 and the soil covering 2 via a pump 25 from a residual soil treatment tank 24 installed on the ground. It passes through the partition wall 6 of the shield machine 1 and communicates with the compartment 26, and separates the treated water of the treatment tank 24, that is, low concentration muddy water mixed with earth and sand, or fresh water from other water supply sources. The mud drainage pipe 23 is used to send the muddy water in the compartment 26 to the residual soil treatment tank 24 using a pump 27, and the water supply pipe 22 is used to transport muddy water in the treatment tank 24. In the embodiment connected to the drainage side, the treated water in the treatment tank 24 is circulated, and in the circulation process, by adjusting and controlling the rotational speed of the pumps 25 and 27, that is, the inflow amount, the water supply pipe 22 and the drainage mud pipe 2
The flow rate and flow velocity in the chamber 3 are maintained at desired values, and the water pressure in the compartment 26 is maintained at a predetermined pressure. On the other hand, the gel-like high-concentration muddy water sent from the high-concentration muddy water tank 14 through the mud feeding pipe 13 by the pump 15 is
The highly concentrated mud water is supplied from the hole 17 to the gap 19 between the front surface of the cutter plate 7 and the face surface 18 or behind the cutter teeth 10, and is applied to the face surface 18 by rotation of the cutter plate 7. A water-impermeable muddy water film is always formed on the face 18. 28 is a water pressure gauge installed in the water pipe 22, 29 is a flow meter installed in the mud removal pipe 23, and 30 is the mud transport pipe 1.
3, which measures the water pressure in the water pipe 22, the amount of sludge removed in the sludge pipe 23, and the sludge pipe 13.
By detecting the amount of high-concentration muddy water flowing out from the water pipe 22 and controlling the rotational speed of each pump 15, 25, and 27, the amount of water supplied from the water pipe 22 and the supply of high-concentration muddy water can be adjusted. In addition to optimizing the balance between the amount of excavating soil and the amount of excavating soil and sludge, the number of revolutions of the cutter plate 7 is measured so that a constant excavation pressure can always be applied to the cutter plate 7.

In addition, the gate 12 mentioned above has high concentration muddy water in the gap 1.
This is to prevent an excessive amount of mud from being supplied into the tank 9 and entering the compartment 26, and the flow meter 30 measures the amount of mud fed from the mud pump 15 and detects that it is excessive. and hydraulic gate jack 1
1, the gate jack 11 is operated to move the gate 12, thereby closing the slit 9 or reducing the opening degree to prevent highly concentrated muddy water from entering the compartment 26. Thus, from the slit 9, only the earth and sand cut by the teeth 10 and the mud film adhering to it are constantly exposed to the compartment 26.
The highly concentrated muddy water can be used effectively without loss.

As described above, the shield construction method according to the present invention includes providing a partition wall at the front of the shield machine, and forming a partition between the opposing surfaces of the partition wall and the fully closed cutter plate provided at the front end opening of the shield machine, The compartment and the earth and sand separation tank placed on the ground are connected and communicated through a water supply pipe and a mud removal pipe, and a highly concentrated mud water tank is installed on the ground, and a plurality of openings are provided in the cutter plate facing toward the face surface. High concentration mud water discharge ports are provided, and these discharge ports and the high concentration mud water tank are connected and communicated by a mud feeding pipe, and the high concentration mud water from the high concentration mud water tank is transferred from a rotating cutter plate through the discharge ports. A mud film is formed on the face by directly supplying it to the face, while fresh water or low-concentration mud is circulated under pressure inside the partition to pressurize the inside of the partition and cut into the partition from the slit in the cutter plate. The excavated soil is discharged through the above-mentioned mud draining pipe, and high concentration mud water is used to form a mud film on the face surface, and the compartment is pressurized to dilute and discharge the excavated soil. Since fresh water or low-concentration mud water is separated and supplied via a separate route, the excavated soil is smoothly separated from the cutter and mixed with water effectively, reducing the resistance inside the mud drainage pipe. Discharge can be accomplished with a small-capacity sludge pump, and the sludge can be transported over long distances. In addition, since highly concentrated muddy water is directly supplied to the gap between the face and the cutter plate and the gap between the cutter teeth, and the cutter plate also applies the highly concentrated muddy water to the face, a mud film is reliably formed on the face. Therefore, even when excavating sandy ground or gravel ground, by adjusting the mixing ratio of highly concentrated mud water, a mud film can be formed on the face surface, and this mud film also prevents water from entering the ground. Since muddy water is prevented from escaping, the amount of muddy water consumed is reduced. Furthermore, since the compartment is filled with low-concentration muddy water, the pressure inside the compartment can be easily controlled, and by maintaining this pressure appropriately, the rotational load on the cutter plate is prevented from becoming excessive. In addition, in the conventional mud water pressure shield construction method, a mud film was formed by circulating mud water, so the mud water concentration changed, making it difficult to excavate sandy or gravel ground. Management can be adjusted and smooth excavation can be carried out even in sandy and gravelly ground. Furthermore, since the shield machine and the ground are connected through piping throughout the tunnel, not only does it not require space for transporting the trolleys, but it also eliminates the need for workers inside the tunnel. It has many benefits such as making autonomous driving possible.

[Brief explanation of the drawing]

The drawings show an embodiment of the method of the present invention, in which Fig. 1 is a simplified explanatory diagram of the excavation state of a tunnel, Fig. 2 is a rear view of the cutter portion, and Fig. 3 is a diagram showing the face portion of the tunnel. A partially omitted cross-sectional side view of the cutter part,
FIG. 4 is an explanatory diagram showing a control system for highly concentrated muddy water, water supply, and mud discharge. DESCRIPTION OF SYMBOLS 1... Shield machine, 6... Bulkhead, 7... Cutter plate, 9... Slit, 10... Cutter tooth, 13... Sludge feed pipe, 14... High concentration mud water tank, 18... Face surface, 22... ...Water pipe, 23...
Sludge drainage pipe, 24... Sediment separation tank, 26... Compartment.

Claims (1)

[Claims] 1. A bulkhead is provided at the front of the shield machine, and a compartment is formed between the opposing faces of the bulkhead and a fully closed cutter plate provided at the front end opening of the shield machine, and the shield machine is placed on the ground. The sediment separation tank is connected and communicated with a fresh water pipe or a low concentration mud water pipe and a mud removal pipe,
Further, a high concentration mud water tank is installed on the ground, and a plurality of high concentration mud water discharge ports opening toward the face are provided in the cutter plate, and these discharge ports and the high concentration mud water tank are connected with a mud feeding pipe. A mud film is formed on the face by directly supplying high-concentration mud from the high-concentration mud tank from the rotating cutter plate to the face through the discharge port, while fresh water or low-concentration mud is fed into the partition wall. A shield construction method characterized in that the inside of the partition wall is pressurized by pressurized circulation, and the excavated earth and sand taken into the partition wall through the slit of the cutter plate is discharged through the mud drainage pipe.