JPH08303188A - Shield machine - Google Patents

Abstract

PURPOSE: To prevent the generation of retention and closing in a sludge withdrawal pipe due to stone contained in soil and sand in a facing, and to discharge soil and sand in the facing smoothly to the rear. CONSTITUTION: A shield machine has a bulkhead 2 parting a facing 32 and an underground section in a section immediately after a cutter head 7 excavating a bedrock 36 in a front section. A sludge discharge opening 4 for discharging soil and sand in the facing is formed and a stop gate 3 opening and closing the sludge discharge opening 4 is fitted to the bulkhead 2. A sludge withdrawal pipe 13 passing soil and sand in the facing through the rear section of the machine is connected to the sludge discharge opening 4. The sectional shape of the sludge withdrawal pipe 13 is formed in an elliptical cross section expanded in the horizontal direction, and the major axis of the sludge withdrawal pipe 13 is formed in 1.15-1.30 to a minor axis. A trommel 14 separating stone contained in soil and sand in the facing into mud and sand while being rotated is installed at the terminal of the sludge withdrawal pipe 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield machine used for excavating tunnels such as headraces and sewers by the semi-shield construction method, which does not cause retention or clogging of earth and sand in the face containing stones. It relates to a shield machine that discharges backwards.

[0002]

2. Description of the Related Art A semi-shield construction method in which a shield machine is used as a front conductor, and immediately after that, a tube that supports the ground is pushed by a jack in the starting shaft behind and buried while promoting In a shield machine used in tunnel excavation with an inner diameter of about 0.8 to 1.2 m, mud is pressed into the face in front of the bulkhead in order to maintain the pressure inside the face and support the excavated ground. The mud pressed into this face mixes with the excavated earth and sand to form a fluid face inside the face. Sediment in the cutting face is introduced from the mud discharge port of the bulkhead into the mud discharge pipe that connects the mud discharge port and the trommel behind the machine. After this, the earth and sand in the cutting face passes through the mud pipe, is separated by trommel into stone and mud and sand, and is collected separately on the ground. As the mud discharge pipe through which the earth and sand inside the cutting face pass, a pipe having a generally circular cross section has been conventionally used. In such a pipe, soil with small specific gravity and fine particles tends to gather in the upper layer, and stones with large specific gravity and large shapes tend to gather in the lower layer. Most of the stones contained in the earth and sand in the face are ellipsoidal-shaped boulders with a ratio of major axis to minor axis of about 1: 0.7, so it is easy for another stone to flow over a stone in the pipe. is there. For this reason, not only the upper and lower stones are involved but the flow in the pipe is stagnated, and not only the discharge speed slows down, but also
When stones stuck to the inner wall of the pipe and could not be removed, the pipe was blocked, which hindered the operation of the entire excavator.

[0003]

The problem to be solved by the present invention is to solve the above-mentioned problems and
(EN) It is intended to provide a shield machine which is less likely to be clogged and which can smoothly discharge the earth and sand in a face to the rear.

[0004]

SUMMARY OF THE INVENTION The structure of the present invention, which has solved the above-mentioned problems, is provided with a bulkhead separating a face and a mine behind a cutterhead for excavating the ground in front of a tunnel. A shield excavator for tunnel excavation that has a mud discharge port for discharging sediment in the face, and a trommel that is provided in the rear to separate mud, sand, and stones and this mud discharge port is connected by a mud pipe. The internal cross-sectional shape of the pipe is an elliptical cross-section that is long in the horizontal direction, and the major axis is 1.15 with the minor axis.
It is in a shield machine, which is characterized by being up to 1.30 times.

[0005]

In the shield machine of the present invention, when the mud opening is opened to discharge the earth and sand in the face, the pressure difference between the face separated by the bulkhead and the inside of the machine including the inside of the machine causes the inside of the face to be cut. Sediment flows into the mud pipe. The mud discharge port is opened only intermittently to maintain the pressure inside the cutting face, but due to the high discharge pressure at the time of discharge, the sediment inside the cutting face moves backward in the mud pipe. The cross-sectional shape of the sludge pipe is an elliptical cross-section that expands in the horizontal direction, and the major axis is 1.15 to 1.30 times the minor axis. Since the curvature of the surface is small and the cross-sectional shape matches the shape of an ellipsoidal cobblestone, even if two cobblestones are piled up and down in the pipe and a circular pipe is clogged, the lower stone is compared to the circular pipe. , It is possible to go down to the lower part of the pipe, and the remaining space for the upper stone to get over the lower stone becomes large. The remaining space is wider in the horizontal direction than the circular pipe and is more suitable for boulders, so that overlapping stones can be flowed without clogging (see FIGS. 7 and 8). Even for the whole earth and sand, the inside of the pipe is smaller than the circular pipe vertically and is wide in the horizontal direction, so uneven distribution of soil, sand, stones etc. is unlikely to occur, and those of different sizes are moderately dispersed in the pipe It can be drained as it is. The earth and sand and stones that have flowed through the pipe in this way enter the trommel behind the excavator, where the earth and sand and stones are separated and collected outside. If the major axis of the sludge pipe deviates from the range of 1.15 to 1.30 times the minor axis, the major axis becomes 1.
If it is less than 15 times, there is no effect of smooth passage of stones, and as with circular pipes, the ratio of cobblestones that are piled up and down increases. On the other hand, if the major axis is larger than 1.30 times, the upper and lower spaces in the pipe are too close, and the size of the largest stone that can be flowed will be smaller than that of a circular pipe with the same cross-sectional area. Becomes difficult to pass.

[0006]

An embodiment of the present invention will be described with reference to the drawings.
The present embodiment is an example of a shield machine in which the major axis of the elliptical section of the sludge discharge pipe is 1.25 times the minor axis. 1 is a front view showing an embodiment, FIG. 2 is a vertical sectional view of a first half portion of the embodiment, FIG. 3 is a vertical sectional view of a second half portion of the embodiment, and FIG. 4 is a horizontal sectional view of a first half portion of the embodiment. 5 is a horizontal sectional view of the latter half of the embodiment, FIG. 6 is a sectional view taken along the line AA of FIG. 2, FIG. 7 is an explanatory view showing the flow state in the sludge pipe of the embodiment, and FIG. 8 is the conventional flow state in the sludge pipe. FIG. 9 is an explanatory view showing a tunnel excavation work using the embodiment. Shield machine 1 of this embodiment
The bulkhead 2 that separates the face 32 and the underground working space immediately after the cutter head 7 that rotates at the forefront to excavate the natural ground 36. The mechanism for driving the cutter head 7 transmits the driving force generated by the electric motor 9 with a speed reducer in the shield 8 to the rotary main shaft 10 penetrating the center of the bulkhead 2 via the gear 11 to directly connect the rotary main shaft 10. The mechanism is such that the head 7 is rotated. On the other hand, the bulkhead 2 is provided with a mud discharge port 4 for discharging sediment in the face, a pressure introduction hole 6 for a pressure sensor 5 for detecting the pressure inside the face, and a mud supply port 12 for press-fitting the face. A stop gate 3 for opening and closing 4 is attached. In the mud discharge port 4,
A mud pipe 13 for connecting the earth and sand in the face introduced from here to the rear of the shield machine 1 is connected. The cross-sectional shape of the sludge pipe 13 is an elliptical cross-section that is expanded in the horizontal direction, and the major axis L is 1.25 times the minor axis R (see FIG. 7). At the end of the mud discharge pipe 13, a trommel 14 is installed which is rotated by a drive unit 15 to separate the stones 34 contained in the earth and sand from the face from the mud and sand. The mud storage tank 16 that stores the separated mud and sand is connected to a tank 27 provided on the ground by a mud discharge pipe 22, and also a vacuum suction device 26 on the ground.
The suction power from is transmitted to here. On the other hand, as a means for discharging the stones 34 separated by the trommel 14, a dolly 24 that transports the stones 34 to the shaft 35 is installed. On the contrary, in order to press the mud into the face 32, a mud feeding device 28 for feeding the mud is provided on the ground, and the mud feeding pipe 23 is connected to the mud feeding port 12 of the bulkhead 2. The shield machine 1 to which each of these devices is connected receives the pressing force from the source push jack 25 installed in the vertical shaft 35 as a natural ground 36.
The pressure receiving portion 18 at the rear end receives the pressure through the fume pipe 31 that supports the pressure hose, and the middle pressing jack 17 immediately in front of the pressure receiving portion 18 supports the pressure receiving portion 18. In the tunnel excavation method using the shield machine 1 of the present embodiment,
The mud fed under pressure from the mud sending device 28 on the ground through the mud sending pipe 23 is fed from the mud feeding port 12 of the bulkhead 2 to the face 3
2 is pressed into the inside of the face to increase the pressure inside the face to prevent the ground 36 from collapsing, and the cutter head 7 is rotated for excavation. Simultaneously with the excavation, the shield machine 1 is propelled by the middle pushing jack 17, and when the pushing amount is propelled by a predetermined amount, the fume pipe 31 is pushed by the former pushing jack 25,
The ground 36 of the tunnel portion is supported and the shield machine 1 as a whole is advanced. The earth and sand 33 and stones 34 excavated by the cutter head 7 are mixed with the mud soil press-fitted into the cutting face 32, and serve as fluid inside the cutting face to maintain the pressure inside the face and prevent the excavated ground from collapsing. When the amount of earth and sand in the face increases and the pressure in the face exceeds an appropriate value, the mud discharge port 4 is opened by the stop gate 3 of the bulkhead 2 to discharge the earth and sand. When the pressure inside the face decreases, the drainage port 4 is closed again by the stop gate 3 so that the pressure inside the face does not drop too much. The earth and sand in the cutting face introduced from the mud discharge port 4 enters the mud discharge pipe 13 and proceeds in the pipe in a state where soil, sand and stone are mixed. The sludge pipe 13 has an elliptical cross-section that extends horizontally, and its major axis is 1.25 with its minor axis being the minor axis.
Due to the double, the sand and sand containing the ellipsoidal cobblestones are evenly distributed, and the stones do not get clogged and flow neatly. When the ratio of the inner diameter of the sludge pipe is out of the above range, the boulders are piled up and down like the circular pipe and are easily clogged, or conversely, the vertical distance in the pipe is too short,
Since the size of the largest boulder that can be flowed is smaller than that of a circular pipe having the same cross-sectional area, the one having the ratio of the major axis to the minor axis of this embodiment is highly practical. The earth and sand and the stone 34 reach the trommel 14 after passing through the mud pipe 13, and are separated into the stone 34 and the mud / sand. The mud and sand enter the mud storage tank 16, are sucked by the vacuum suction device 26, pass through the mud discharge pipe 22, and enter the tank 2
Recovered to 7. A part of the mud collected in the tank 27 is sent to the mud sending device 28 and returned to the cutting face 32 again.
On the other hand, the stones 34 separated by the trommel 14 are collectively carried by the truck 24 to the shaft 35, and are carried out to the outside. Inside the shield machine 1, a worker can work from the rear up to the trommel 14 part. When the trommel 14 is clogged with soil, the worker directly removes it.

[0007]

EFFECTS OF THE INVENTION According to the present invention, by adopting a construction in which the cross section of the sludge discharge pipe is horizontally long and has an ellipse whose major axis is 1.15 to 1.30 times the minor axis, a large stone is discharged inside the sludge pipe. Sediment including sand flows smoothly and retention and blockage are hard to occur,
The stones can be discharged quickly, and the frequency of work to clear the clogging of the mud pipe is significantly reduced, so that the overall excavation work can proceed efficiently.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment.

FIG. 2 is a vertical sectional view of a first half portion of the embodiment.

FIG. 3 is a vertical sectional view of the latter half of the embodiment.

FIG. 4 is a horizontal sectional view of a first half portion of the embodiment.

FIG. 5 is a horizontal sectional view of the latter half of the embodiment.

6 is a cross-sectional view taken along the line AA of FIG.

FIG. 7 is an explanatory diagram showing a fluidized state in the sludge discharge pipe of the embodiment.

FIG. 8 is an explanatory view showing a flow state in a conventional sludge discharge pipe.

FIG. 9 is an explanatory diagram showing a tunnel excavation work using an example.

[Explanation of symbols]

 1 shield machine 2 bulkhead 3 stop gate 4 mud discharge port 5 pressure sensor 6 pressure introduction hole 7 cutter head 8 shield 9 electric motor with speed reducer 10 rotating main shaft 11 gear 12 mud supply port 13 drainage pipe 14 trommel 15 drive device 16 Mud tank 17 Medium push jack 18 Pressure receiving part 19 Packing 20 Vitric joint 21 Direction correction jack 22 Draining pipe 23 Mud sending pipe 24 Truck 25 Original push jack 26 Vacuum suction device 27 Tank 28 Mud sending device 29 Mine air blowing compressor 30 Air pipe 31 Hume pipe 32 Face 33 Soil 34 Stone 35 Vertical shaft 36 Rock

Claims (1)

[Claims] 1. A bulkhead for separating a face and a mine is provided on the rear side of a cutter head for excavating the ground in front of a tunnel, and the bulkhead is provided with a sludge discharge port for discharging sediment in the face and provided on the rear side. In a shield excavator for tunnel excavation, in which a trommel that separates the mud, sand and stones that has been separated and this drainage port are connected by a drainage pipe, the cross-sectional shape of the inside of the drainage pipe is an elliptical cross section that is elongated in the horizontal direction. 1.15 whose major axis is the minor axis
~ 1.30 times the shield machine.