JP7430026B2 - Mud water shield excavator - Google Patents

Description

TECHNICAL FIELD The present invention relates to a muddy water type shield excavator that excavates a ground to form a tunnel while stabilizing a face by applying a predetermined pressure to muddy water in a cutter chamber.

In the shield construction method, which constructs a tunnel in the ground, a shield excavator is assembled in the starting shaft and launched to excavate underground. After reaching the reaching shaft, the shield tunneling machine is disassembled inside the reaching shaft and transported to the ground.

In addition, the shield excavators used in the shield method include mud pressure shield excavators, which turn the excavated soil into mud and apply a specified pressure to excavate the ground while stabilizing the face, and There are mud shield excavators that excavate the ground while stabilizing the face by applying pressure.

Here, in the muddy water type shield excavator, muddy water is constantly supplied into the cutter chamber from the mud feeding pipe, and the muddy water pressure in the cutter chamber is measured and managed with a pressure gauge. The mud pressure in the cutter chamber is made to slightly exceed the pressure (earth pressure and water pressure) in front of the face, and the mud pressure in the cutter chamber counteracts the pressure in front of the face, thereby stabilizing the face. During excavation, the muddy water accumulated in the cutter chamber is discharged to the outside from the mud drain pipe together with the excavated soil taken into the cutter chamber (excavation mode). In addition, when stopping excavation such as when assembling segments, open the valve (bypass valve) installed in the bypass pipe that communicates the sludge pipe and the sludge pipe, and The valves (sludge feeding valve/sludge removal valve) installed closer to the cutter head than the bypass piping are closed to circulate muddy water with the cutter chamber separated (bypass mode). Furthermore, when the segment assembly is completed and excavation is restarted, the bypass valve is closed, and the mud feeding valve and mud draining valve are opened.

The cutter head has a gap for taking the excavated earth and sand into the cutter chamber, and the muddy water inside the cutter chamber presses down the ground at the face. The mud supplied into the cutter chamber contains bentonite, polymer additives, etc. mixed into the mud, which forms a film (mud film) on the face of the face to counteract the pressure in front of the face. There is. In the case of sandy soil where water easily drains, the amount of mud water flowing in increases (sludge state), so the amount of mud and polymer additives in the mud water is increased, and the amount of mud water supplied is increased. Operations are being carried out to stabilize the pressure inside the cutter chamber by increasing the amount of muddy water discharged. In addition, in the case of clayey soil that does not allow water to drain easily, the operation is reversed.

When excavating with a mud shield excavator, the concentration of mud water supplied to the cutter chamber is adjusted according to fluctuations in the mud water pressure in the cutter chamber depending on the soil quality of the ground, and the mud supply pipe and mud discharge pipe are adjusted. It is necessary to adjust the flow rate of the pipe. However, in complex ground or under high water pressure, the mud water pressure inside the cutter chamber may fluctuate rapidly, and if such concentration and flow rate adjustments are not made in time, it may have an adverse effect on the ground and cause it to collapse. There is a possibility.

Additionally, when transitioning from bypass mode to excavation mode, the mud water pressure inside the cutter chamber fluctuates greatly as each valve closes and opens instantly, causing the face rock, cutter head, There is a possibility that there will be an adverse effect on the sludge pipes, sludge drainage pipes, etc.

Therefore, in Patent Document 1 (JP 2013-083110A) and Patent Document 2 (JP 2002-180781A), a chamber that utilizes the elasticity of compressed air is provided separately from the cutter chamber, and the cutter chamber A technology has been proposed to alleviate rapid fluctuations in mud water pressure by responding to changes in the water level of mud water.

Specifically, the technique described in Patent Document 1 has a structure in which an air chamber, which is a second chamber, is provided behind a cutter chamber, which is a first chamber, and the entire chamber is divided vertically into two tanks. The rear air chamber is connected to the cutter chamber at the bottom and supplied with muddy water, and is connected at the top to the compressor and supplied with compressed air. When the pressure applied to the cutter chamber fluctuates, the water level in the air chamber rises and falls, but compressed air is supplied or discharged accordingly, and pressure fluctuations in the muddy water in the cutter chamber are alleviated.

Furthermore, the technique described in Patent Document 2 has a structure in which a pressure adjustment tank, which is a second chamber, is provided in a tunnel that is separate from a cutter chamber, which is a first chamber. The pressure adjustment tank is connected at the lower end to the cutter chamber to be supplied with muddy water, and at the upper end is connected to a damper tank containing compressed air to be supplied with compressed air. When the pressure applied to the cutter chamber fluctuates, the water level in the pressure adjustment tank rises and falls, but compressed air is supplied or discharged accordingly, and pressure fluctuations in the muddy water in the cutter chamber are alleviated.

JP2013-083110A Japanese Patent Application Publication No. 2002-180781

In this way, in addition to the first chamber (cutter chamber), a second chamber (air chamber/pressure adjustment tank) containing compressed air and muddy water is provided between the first chamber and the second chamber. In a muddy shield excavator, muddy water moves back and forth to alleviate rapid fluctuations in muddy water pressure in the first chamber, and the highly concentrated muddy water containing a lot of earth and sand in the first chamber flows into the second chamber. There may be an influx.

Then, the earth and sand obstruct smooth flow of muddy water between the first chamber and the second chamber, and the responsiveness of the second chamber to changes in the muddy water pressure in the first chamber deteriorates.

The present invention was made based on the above-mentioned technical background, and an object of the present invention is to provide a muddy water type shield excavator that can suppress the intake of earth and sand from a first chamber to a second chamber.

In order to solve the above problems, a muddy water type shield excavator according to the present invention as set forth in claim 1 includes a first chamber formed between a cutter head and a partition wall, and a muddy water pump that sends muddy water into the first chamber. a mud feeding pipe, a mud draining pipe for discharging the muddy water stored in the first chamber to the outside together with the excavated soil taken into the first chamber, and a pressure regulating pipe that accommodates compressed air and muddy water. a second chamber that communicates with the first chamber through the pressure regulating piping, and allows muddy water to flow back and forth between the first chamber and the first chamber to alleviate fluctuations in muddy water pressure in the first chamber; The connection position of the pressure regulating piping on the first chamber side is above the center of the partition wall in the height direction of the first chamber.

In the mud water type shield excavator of the present invention according to claim 2, in the invention according to claim 1, the connection position of the mud feeding pipe on the first chamber side is the connection position of the pressure regulating pipe in the partition wall. It is characterized by being above the position.

According to the present invention, the connection position of the pressure regulating piping on the first chamber side is set above the center of the height direction of the first chamber in the partition wall, so that there is no connection from the first chamber to the second chamber. , relatively low-concentration muddy water that does not contain much sediment will flow into the area. This makes it possible to suppress the intake of earth and sand from the first chamber to the second chamber.

Therefore, muddy water can smoothly flow back and forth between the first chamber and the second chamber, and good responsiveness to changes in muddy water pressure in the first chamber caused by the second chamber is exhibited. be able to.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic side view of the inside of a muddy water type shield excavator according to an embodiment of the present invention. An explanatory diagram showing the cutter head of the muddy shield excavator in Figure 1 from the front, and also showing the positions of the mud feeding pipe, mud removal pipe, and pressure regulating pipe connected to the bulkhead, and the position of the pressure gauge installed on the bulkhead. It is. FIG. 2 is an explanatory diagram showing the flow of muddy water during earth excavation in the shield excavator of FIG. 1; FIG. 2 is an explanatory diagram showing the flow of muddy water when earth excavation is stopped in the shield excavator of FIG. 1;

EMBODIMENT OF THE INVENTION Hereinafter, embodiment as an example of this invention will be described in detail based on drawing. In addition, in the drawings for explaining the embodiments, the same components are designated by the same reference numerals in principle, and repeated explanation thereof will be omitted.

FIG. 1 is a conceptual diagram showing the configuration of a muddy shield tunneling machine from the side, which is an embodiment of the present invention, and FIG. 2 shows the cutter head of the muddy shield tunneling machine of FIG. FIG. 2 is an explanatory diagram showing the positions of a mud feeding pipe, a mud draining pipe, and a pressure regulating pipe, and the position of a pressure gauge installed on a partition wall.

In FIG. 1, a muddy water type shield excavator (hereinafter simply referred to as "shield excavator") 1 according to the present embodiment excavates the ground by pressing a cutter head 2 against a face (excavation surface) F and rotating it. When excavating, mud water is supplied to the cutter chamber (first chamber) 4 provided in the skin plate 3 on the back of the cutter head 2 through the mud feed pipe 5, and the mud water pressure in the cutter chamber 4 is adjusted to the pressure of the face F. In addition to stabilizing the face F by applying pressure commensurate with earth pressure and groundwater pressure, the muddy water accumulated in the cutter chamber 4 is discharged to the outside of the tunnel along with the excavated soil taken into the cutter chamber 4 through the mud draining pipe 6. while forming a tunnel in the ground. Note that the muddy water sent into the cutter chamber 4 is stored in a muddy water plant 7 installed outside the mine, and is pumped by a mud pump 8 . In addition, bentonite and polymer additives are mixed into the muddy water, which forms a film (mud film) on the face F to prevent the muddy water from flowing into the gaps in the ground in front. There is.

The muddy water type shield excavator 1 has a stabilizing effect on the face F due to penetration of muddy water, so it is suitable for construction on ground with high water pressure. On the other hand, in highly permeable ground or megalithic ground, there is a risk of mud slippage, where a large amount of muddy water flows in from the ground. Increase the volume and reinforce the mud film to stabilize the pressure inside the cutter chamber.

The cutter head 2 constituting the shield excavator 1 is an excavation member having a circular shape in front view for excavating the face F of the earth, and is mounted on the front surface of the skin plate 3 to rotate in forward and reverse directions along the circumferential direction of the skin plate 3. It is installed freely.

As shown in FIG. 2, the cutter board 2 is a face plate type, and includes a central hub part 2-1, main spokes 2-2 extending radially from the hub part 2-1 toward the outer periphery, and each main spoke. 2-2, and an outer ring portion 2-4 connecting the tips of the main spokes 2-2 and the sub-spokes 2-3.

The front surfaces (faces facing the face) of the hub portion 2-1, main spokes 2-2, sub-spokes 2-3, and outer ring portion 2-4 of the cutter board 2 are used for crushing boulders, etc., and excavating ground. In addition to being equipped with a plurality of bits 2a and scraper teeth 2b for cutting, an earth and sand intake port 2-5 is formed for taking earth and sand excavated by the rotation of the cutter board 2 into the cutter chamber 4. A copy cutter 2c is attached to the outer circumferential surface of the cutter board 2 to perform over-digging when constructing a sharp curve, control the posture of the shield excavator 1, and the like.

In FIG. 1, the skin plate 3 located at the rear of the cutter head 2 is formed of, for example, a steel plate having a cylindrical cross section in the radial direction. A partition wall 9 is installed at a position retreating inward from the front surface of the skin plate 3 (the position where the cutter head 2 is installed) to partition the inside of the skin plate 3 into a face side and a machine inside side. A cutter chamber 4, which is a first chamber, is formed on the face side of the skin plate 3, that is, between the cutter head 2 and the partition wall 9.

The cutter chamber 4 is a space (chamber) in which earth and sand excavated by the rotation of the cutter head 2 is taken in and mixed with mud water supplied through the mud feed pipe 5. As mentioned above, the mud water pressure inside the cutter chamber 4 is is made to a pressure commensurate with the earth pressure and groundwater pressure of the face F, and the face F is held down and stabilized.

On the other hand, inside the skin plate 3, there is a cutter drive unit that rotates the cutter head 2 in forward and reverse directions, and a skin plate 3 that is divided into front and rear parts and can be bent (front body plate and rear body plate), which are interconnected. At the same time, there is a bending jack that corrects the propulsion direction of the shield excavator 1, a shield jack that moves the shield excavator 1 forward by taking a reaction force from the segment laid behind the skin plate 3, and a shield jack that moves the shield excavator 1 forward by taking a reaction force from the segment laid behind the skin plate 3, near the rear end of the skin plate 3. Erectors are installed that assemble multiple pieces into a ring to construct segments around the tunnel's inner circumference.

Furthermore, the aforementioned mud feeding pipe 5 and mud draining pipe 6 are installed so as to extend from the inside of the skin plate 3 to the outside of the mine.

The mud feeding pipe 5 is a pipe that supplies muddy water into the cutter chamber 4, and is made of, for example, steel. The tip portion (sludge discharge port) of the mud feeding pipe 5 passes through the upper part of the front face of the partition wall 9 and reaches the cutter chamber 4 . As a result, the muddy water pumped through the mud feeding pipe 5 is supplied into the cutter chamber 4 from the upper part of the front of the shield excavator 1 . This mud feeding pipe 5 extends toward the entrance of the tunnel, and is connected to the muddy water plant 7 outside the tunnel via the aforementioned mud feeding pump 8 disposed along the way. Note that the muddy water plant 7 is connected to a muddy water treatment device (not shown) outside the tunnel.

The mud discharge pipe 6 is a pipe for discharging mud water (mixed mud water of excavated soil and mud water) in the cutter chamber 4 to the outside of the tunnel, and is made of, for example, steel. The tip portion (sludge suction port) of the mud removal pipe 6 passes through the lower part of the front surface of the partition wall 9 and reaches the cutter chamber 4 . As a result, the waste water in the cutter chamber 4 is discharged from the front lower part of the shield excavator 1. The mud removal pipe 6 extends toward the entrance of the tunnel, and is connected to a muddy water treatment device outside the tunnel via a mud removal pump 10 disposed along the way.

That is, the waste water in the cutter chamber 4 is sent to the mud water treatment device outside the tunnel through the mud removal pipe 6, where it is separated into earth and sand and mud water, and the specific gravity, viscosity, etc. are adjusted, and then sent to the mud water plant 7. The slurry is then sent to the cutter chamber 4 through the feed pipe 5 again.

As shown in FIG. 1, an auxiliary chamber (second chamber) 11 is installed behind the cutter chamber 4 in the shield excavator 1 of this embodiment. The auxiliary chamber 11 communicates with the cutter chamber 4 through a pressure regulating pipe 13, and is a small pressure vessel in which muddy water flows back and forth between the auxiliary chamber 11 and the cutter chamber 4.

Since the auxiliary chamber 11 is connected to the cutter chamber 4 through the pressure regulating pipe 13, the lower layer inside the auxiliary chamber 11 is a muddy water layer (reserved muddy water). As shown in FIGS. 1 and 2, in this embodiment, the connection position of the pressure regulating pipe 13 on the cutter chamber 4 side is above the center of the partition wall 9 in the height direction of the cutter chamber 4. This is because the role of the auxiliary chamber 11 is to adjust the pressure, so the concentration of muddy water does not affect the function, so it is desirable that the concentration of muddy water in the auxiliary chamber 11 is low. That is, the muddy water in the cutter chamber 4 is thick near the bottom and becomes thinner as the height increases, so if the pressure regulating pipe 13 is connected near the bottom of the cutter chamber 4, the highly concentrated muddy water in the cutter chamber 4 will be reduced. In other words, muddy water containing a large amount of earth and sand flows into the auxiliary chamber 11, and the earth and sand tend to accumulate at the bottom of the auxiliary chamber 11, impeding smooth movement of the muddy water between the cutter chamber 4 and the auxiliary chamber 11. It becomes like this. Therefore, since it is necessary to suppress the intake of earth and sand by allowing relatively low concentration muddy water to flow in, the connection position of the pressure regulating pipe 13 on the cutter chamber 4 side is set as described above.

As shown in FIGS. 1 and 2, the connection position of the mud feeding pipe 5 on the cutter chamber 4 side is above the connection position of the pressure regulating pipe 9 on the partition wall 9, and is close to the upper end. ing. This is because the mud water pressure inside the cutter chamber 4 decreases as it goes upward, so by connecting the mud feeding pipe 5 to a position where the mud water pressure is low, mud water can smoothly flow into the cutter chamber 4. It's for a reason.

Further, as shown in FIG. 1, in this embodiment, the pressure regulating pipe 13 is connected to a position including the bottom of the auxiliary chamber 11. This is to ensure that the pressure regulating pipe 13 faces the muddy water layer within the auxiliary chamber 11. However, this type of connection is not necessarily required.

As shown in FIG. 1, a receiver tank 14 is installed which receives compressed air from a compressor 16, and this receiver tank 14 is constantly connected to the auxiliary chamber 11 via a pneumatic pipe 15. Therefore, the upper part of the auxiliary chamber 11 is a compressed air layer. In this embodiment, the pneumatic piping 15 does not have a pressure adjustment function, and constantly supplies compressed air stored in the receiver tank 14 to the auxiliary chamber 11. Furthermore, a pressure adjustment valve 17 is attached to the upper surface of the auxiliary chamber 11 to maintain the air pressure in the auxiliary chamber 11 at a set value by adjusting the opening degree of the valve according to the pressure.

In this embodiment, the compressed air generated by the compressor 16 is 0.75 MPa (MAX), and the pressure is adjusted to 0.31 to 0.35 MPa by a pressure regulating valve (not shown) installed between the compressor 16 and the receiver tank 14. It is depressurized to a certain degree and sent into the receiver tank 14. The reduced pressure compressed air is sent into the auxiliary chamber 11 from the receiver tank 14, and the pressure inside the auxiliary chamber 11 is adjusted by the pressure regulating valve 17 so that the pressure is 0.3 MPa.

Note that the pressure regulating valve 17 may be one whose opening degree changes automatically depending on air pressure, or may be one whose opening degree is controlled by a servo motor or the like. However, the opening degree of the pressure regulating valve 17 is desirably about 10% from the viewpoint of ease of control.

Further, when the pressure inside the receiver tank 14 becomes lower than 0.31 MPa, the compressor 16 starts operating, and when it becomes higher than 0.35 MPa, it stops. Compressed air is always supplied to the auxiliary chamber 11 from the receiver tank 16. In addition, by constantly discharging air from the pressure adjustment valve 17 of the auxiliary chamber 11, a stable atmospheric pressure can be maintained.

In this embodiment, the capacity of the auxiliary chamber 11 is 5.0 m ³ while the capacity of the receiver tank 14 is 2.26 m ³ . Note that the compressor 16 is used at its maximum output, and a compressor with a large output is desirable.

Since the internal pressure of the auxiliary chamber 11 is kept constant in this way, muddy water flows in from the pressure regulating pipe 13 in response to fluctuations in the pressure of the cutter chamber 4, and the water surface height of the muddy water layer changes. However, the pressure on the face F of the cutter head 2 can be kept constant because the upper compressed air acts as a pneumatic damper and absorbs fluctuations in the face pressure.

However, the numerical values such as pressure and capacity shown above are merely examples, and it goes without saying that the present invention is not limited to these numerical values.

Note that the receiver tank 14 is always connected to the compressor 16, but if the pressure of compressed air in the receiver tank 14 exceeds a certain value, the compressor 16 will stop and the pressure in the receiver tank 14 will rise above a predetermined value. is prevented.

Further, a compressed air supply means composed of a receiver tank 14 and a compressor 16 is mounted on a trailing truck that moves forward following the forward movement of the shield excavator 1.

A pressure gauge P for detecting mud water pressure in the cutter chamber 4 is installed at the center of the partition wall 9 in the height direction.

The pressure gauge P is for controlling the mud water pressure in the cutter chamber 4 to a pressure that opposes the pressure in front of the face. The mud water pressure in the face F and the cutter chamber 4, like the water pressure, is low at the top and increases as it goes downward. The pressure inside the cutter chamber 4 is managed by estimating the value detected by the pressure gauge P, which is the value at the center position of the partition wall 9 in the height direction, as the overall average value. Therefore, the center of the partition wall 9 in the height direction is at the mud water pressure management height. However, the mud water pressure management height does not need to be at the center of the partition wall 9 in the height direction; for example, the mud water pressure management height may be set to the average value obtained from the actual mud water pressure distribution in the cutter chamber 4. Good too.

Note that the pressure gauge P does not need to be located at one location in the center of the partition wall 9 in the height direction. In other words, in the case of a shield tunneling machine 1 having a relatively small diameter, one location can be provided on each side of the center of the partition wall 9 in the height direction. In addition, in the case of a shield tunneling machine 1 having a relatively large diameter, it can be provided on the right and left sides of the center in the height direction of the bulkhead 9, and above and below the center, and the trapezoid shape where the mud water pressure becomes higher as it goes downward. It is possible to estimate and manage the value at the center in the height direction assuming a distribution of .

In this embodiment, two (plural) pneumatic pipes 15 are provided to supply compressed air from the receiver tank 14 to the auxiliary chamber 11, and the pressure of the compressed air in the auxiliary chamber 11 is kept constant. Two (plural) pressure regulating valves 17 are also provided.

Each pneumatic piping 15 and pressure regulating valve 17 has a capacity that can ensure the required air flow rate and pressure retention, and normally functions at half of its original capacity. . As a result, if a malfunction occurs in one of the pneumatic piping 15 or the pressure regulating valve 17, the other will automatically respond, making it possible to repair without stopping excavation. ing. Additionally, in the unlikely event that the amount of air flowing exceeds what was expected at the time of design, it is possible to accommodate up to twice as much. Since the pneumatic piping 15 and the pressure regulating valve 17 are always in operation, the capacity only changes due to malfunctions or unexpected flow rates, so it is possible to respond more quickly than if they were kept as a reserve. I can do it.

Furthermore, a supply pipe 12 branched from the mud feeding pipe 5 is connected to the auxiliary chamber 11, so that the muddy water flowing through the mud feeding pipe 5 can also flow into the auxiliary chamber 11. Further, a discharge pipe 18 is connected to the mud removal pipe 6 so as to extend from the bottom surface of the auxiliary chamber 11 . Further, the mud feeding pipe 5 and the mud draining pipe 6 are directly connected by a bypass pipe 19 (that is, without going through the cutter chamber 4).

Here, the discharge pipe 18 extending from the auxiliary chamber 11 is connected to the mud removal pipe 6 because the sand accumulated in the auxiliary chamber 11 is sucked through the discharge pipe 18 by the pressure of the flowing water in the mud removal pipe 6. This is because it is possible. In order to efficiently discharge the earth and sand in the auxiliary chamber 11, the discharge pipe 18 is preferably connected to extend from the bottom surface of the auxiliary chamber 11.

Further, as shown in the figure, the merging connection point Pm of the discharge pipe 18 with the mud removal pipe 6 is located upstream of the mud removal pump 10 described above in the flow direction of mud. This is because if the confluence connection point Pm is placed downstream of the mud drain pump 10 in the flow direction of muddy water, when the pressure inside the mud drain pipe 6 is large, the suction force into the auxiliary chamber 11 is too strong. This is because the water level may drop too much. However, if the amount of sediment in the auxiliary chamber 11 is large, the confluence connection point Pm may be placed downstream of the mud removal pump 10 in the flow direction of the muddy water, and furthermore, the confluence connection point Pm may be placed on the upstream and downstream sides of the confluence connection point Pm. The sludge pump 10 may be connected to the sludge pump 10 and operated selectively depending on the situation.

In this embodiment, a mud removal tank 20 is connected to the bottom surface of the auxiliary chamber 11 via a drain pipe 21. When the muddy water in the auxiliary chamber 11 contains a large amount of earth and sand, the seventh valve V7 provided in the drain pipe 21 is opened to discharge the earth and sand in the auxiliary chamber 11 into the mud removal tank 20. ing. Therefore, even if the muddy water in the auxiliary chamber 11 is discharged from the drain pipe 21, the inside of the tunnel will not be contaminated with muddy water. Note that the muddy water in the mud removal tank 20 is sucked under negative pressure by a vacuum cleaner (not shown) through the suction pipe 22 and discharged to the outside of the machine.

In this way, in the shield excavator 1 of the present embodiment, the mud water is discharged from the auxiliary chamber 11 through the first route from the discharge pipe 18 to the mud removal pipe 6, and from the drain pipe 21 into the mud removal tank. Two routes are provided, a second route for discharging to 20. This assumes that although it is necessary to discharge the muddy water in the auxiliary chamber 11, it is no longer possible to discharge it through the first route due to the high water pressure in the mud draining pipe 6. . However, even if muddy water can be discharged through the first route, it may be discharged through the second route or by using the first route and the second route in combination. Furthermore, only one of the first route and the second route may be provided.

Furthermore, a water level gauge (not shown) is installed in the auxiliary chamber 11. This water level gauge is used to detect the flow direction of muddy water flowing back and forth between the auxiliary chamber 11 and the cutter chamber 4 (in which direction the muddy water is flowing) by measuring increases and decreases in the water level in the auxiliary chamber 11. belongs to. However, instead of the water level gauge, a flow direction meter may be installed in the pressure regulating pipe 13 to detect the flow direction of the muddy water flowing back and forth between the auxiliary chamber 11 and the cutter chamber 4.

As shown in the figure, the first valve V1 is located closer to the cutter chamber 4 than the branch connection point Pb1 with the bypass pipe 19 in the mud feeding pipe 5, and the first valve V1 is located closer to the cutter chamber 4 than the branch connection point Pb2 with the bypass pipe 19 in the mud removal pipe 6. A second valve V2 is attached to the cutter chamber 4 side. Further, the bypass pipe 19 has a third valve V3, the supply pipe 12 has a fourth valve V4, the discharge pipe 18 has a fifth valve V5, and the pressure regulation pipe 13 has a sixth valve V6. installed. Furthermore, as described above, the seventh valve V7 is attached to the drain pipe 21 that connects the auxiliary chamber 11 and the mud removal tank 20.

These valves V1 to V7 are for opening and closing their respective pipelines, and in this embodiment, the shield excavation machine 1 is used in various operating states (during earth excavation work/during earth excavation work stopped). , measured values by the pressure gauge P and concentration meter of muddy water in the cutter chamber 4, measured values by the water level gauge and water meter (described later) and pressure gauge P in the auxiliary chamber 11, etc., and based on these, The opening and closing operations are automatically performed by an actuator such as a motor that is controlled by a control section (not shown).

However, the valves V1 to V7 may be opened and closed by an operator via actuators without providing a control section.

Note that a check valve (eighth valve) V8 is installed on the mud removal pipe 6 side of the fifth valve V5 attached to the discharge pipe 18. This prevents muddy water from flowing back from the mud drain pipe 6 through the discharge pipe 18 into the auxiliary chamber 11 when the water pressure in the mud drain pipe 6 is higher than the water pressure in the discharge pipe 18. This is to prevent it.

The flow of muddy water in the shield excavator 1 having the above configuration will be explained using FIGS. 3 and 4. In FIGS. 3 and 4, pipes through which muddy water flows are shown by thick solid lines, and pipes through which muddy water flows or not are shown by thick broken lines, respectively. Further, FIG. 3 shows a cutter chamber circulation mode in which muddy water circulates through the cutter chamber 4 (that is, without passing through the bypass pipe 19), and FIG. A bypass reflux mode is shown in which the flow is refluxed (without passing through chamber 4). Further, the valves V1 to V7, which open and close the pipes to control the flow of muddy water, are controlled by the control section as described above.

In FIG. 3, when excavating the earth, the sixth valve V6 is first opened. Subsequently, the first valve V1 and the second valve V2 are opened, and the third valve V3 is closed (cutter chamber circulation mode). Then, the muddy water stored in the muddy water plant 7 is supplied through the muddy pipe 5 into the cutter chamber 4 by the muddy pump 8, and the muddy water pressure in the cutter chamber 4 is adjusted to a pressure commensurate with the earth pressure of the face F and the groundwater pressure. In addition to stabilizing the face F, the muddy water accumulated in the cutter chamber 4 is circulated along with the excavated soil taken into the cutter chamber 4 through the muddy water plant 7 outside the tunnel through the mud drainage pipe 6. form a tunnel.

In addition, depending on the change in muddy water pressure inside the cutter chamber 4, the muddy water moves back and forth between the cutter chamber 4 and the auxiliary chamber 11 via the pressure regulating pipe 13, and the pressure fluctuation inside the cutter chamber 4 is alleviated. .

At this time, since the connection position of the pressure regulating pipe 13 on the cutter chamber 4 side is above the center of the height direction of the cutter chamber 4 in the partition wall 9, the connection position from the cutter chamber 4 to the auxiliary chamber 11 is relatively small. The inflow of low-concentration muddy water suppresses the uptake of sediment.

Note that, in this way, the sixth valve is in the open position and the auxiliary chamber 11 is constantly connected to the cutter chamber 4. However, if some unexpected situation occurs and the amount of muddy water in the auxiliary chamber 11 suddenly and extremely increases or decreases, the auxiliary chamber 11 will no longer be able to alleviate the pressure fluctuations in the cutter chamber 4. Therefore, only in that case, the connection between the two is released by closing the sixth valve V6.

In this embodiment, the concentration of muddy water in the cutter chamber 4 is adjusted as follows. In other words, whether or not the sludge is being lost is determined based on the calculation result of the amount of sludge, and this is done even when the water level of the auxiliary chamber 11 is not changing. Specifically, when the amount of sludge lost in a day (=(sludge feeding amount + excavated soil amount) - sludge amount) is 10% or more of the total amount, it is considered to be a sludge lost state. The concentration of mud water is controlled by specific gravity, and the standard is 1.2, but it is increased to 1.25 when mud is lost. Further, the specific gravity of mud water is set to be about 1.3 at maximum, and the standard is set to 1.22 when the amount of lost mud is not large.

Additionally, if the amount of mud lost per day is less than 1% of the total amount, it will be determined that the mud loss has subsided, and the possibility of returning the concentration of mud to 1.2 will be considered. The reason we left room for not returning the muddy water concentration to 1.2 was because changing the muddy water concentration would require major adjustments such as changes to the above-ground vibrating sieve and thickener back filter. Therefore, if there is no problem with excavating with increased concentration of mud water, it is desirable to continue the excavation as it is.

Moreover, contrary to water loss, the water pressure at the face F may become high, and groundwater may flow into the cutter chamber 4, causing the water level to rise. In this embodiment, the allowable value at this time is plus or minus 3%, and if the water level continues to rise by 3% or more for a whole day, the mud pressure in the cutter chamber 4 is gradually increased and the face F balance with. The mud pressure in the cutter chamber 4 is adjusted within the range of a control value (between the active earth pressure and the passive earth pressure of the ground) using a pressure gauge P, and when it returns to within the allowable value, the mud pressure is returned. During this time, the air pressure in the auxiliary chamber 11 is also adjusted to be higher than the standard value in accordance with the mud pressure.

As mentioned above, the auxiliary chamber 11 is connected to the supply pipe 12 branched from the mud feed pipe 5 to the cutter chamber 4, and is further connected to the discharge pipe 12 to prevent the amount of muddy water inside the auxiliary chamber 11 from becoming too large. 18 is connected to the mud removal pipe 6. Further, a fourth valve is installed in the supply pipe 12, and a fifth valve is installed in the discharge pipe 18, respectively. Therefore, when excavating the earth, by appropriately opening and closing the fourth valve V4 and the fifth valve V5, the amount of water in the auxiliary chamber 11 is adjusted according to the measured value of a water meter (not shown) that measures the amount of water in the auxiliary chamber 11. The amount of muddy water in 11 is adjusted.

As a result, even if mud escape occurs in the cutter chamber 4 and muddy water in the auxiliary chamber 11 flows into the cutter chamber 4 from the pressure regulating pipe 13, the fourth valve V4 is opened and the muddy water in the mud feeding pipe 5 flows into the supply pipe. 12 into the auxiliary chamber 11, the water level may become too low and excavation stops, or the water level may become even lower and compressed air from the auxiliary chamber 11 flows into the cutter chamber 4 through the pressure regulating pipe 13. There's nothing left to do.

Next, as shown in FIG. 4, when earth excavation is stopped, such as when assembling segments, excavation by the cutter head 2 is stopped and the pressure at the face F does not change, so the mud water pressure in the cutter chamber 4 is reduced to that level. To fix the current pressure, the first valve V1 and the second valve V2 are closed and the third valve V3 is opened (bypass recirculation mode). As a result, muddy water is not supplied into the cutter chamber 4, but flows from the mud feeding pipe 5 via the bypass pipe 19 to the mud removal pipe 6, and after the excavated earth and sand are removed outside the tunnel, the muddy water is not supplied into the cutter chamber 4. The slurry is circulated through the plant 7 by the slurry pump 8.

Thus, according to the present embodiment, the connection position of the pressure regulating pipe 13 on the cutter chamber 4 side is above the center of the partition wall 9 in the height direction of the cutter chamber 4. Therefore, when muddy water moves back and forth between the cutter chamber 4 and the auxiliary chamber 11 via the pressure regulating pipe 13 in response to fluctuations in the muddy water pressure in the cutter chamber 4, the flow from the cutter chamber 4 to the auxiliary chamber 11 is as follows. Mud water with a relatively low concentration flows in, suppressing the uptake of sediment.

As a result, muddy water can flow smoothly between the cutter chamber 4 and the auxiliary chamber 11, and it is possible to exhibit good responsiveness to changes in the muddy water pressure in the cutter chamber 4 caused by the auxiliary chamber 11. As a result, pressure fluctuations in the muddy water within the cutter chamber 4 can be reliably alleviated.

As above, the invention made by the present inventor has been specifically explained based on the embodiments, but the embodiments disclosed in this specification are illustrative in all respects, and are limited to the disclosed technology. It's not a thing. In other words, the technical scope of the present invention should not be construed in a limited manner based on the description of the embodiments described above, but should be construed solely in accordance with the description of the claims, and the scope of the claims This invention includes techniques equivalent to the techniques described in , and all changes without departing from the gist of the claims.

In the above explanation, the present invention was applied to a muddy water type shield excavator, but there are no particular limitations on points that are not related to the present invention, such as the shape and structure of the cutter head.

1 Shield tunneling machine 2 Cutter head 3 Skin plate 4 Cutter chamber (first chamber)
5 Sludge pipe 6 Sludge drain pipe 7 Mud water plant 8 Sludge pump 9 Partition wall 10 Sludge pump 11 Auxiliary chamber (second chamber)
12 Supply piping 13 Pressure adjustment piping 14 Receiver tank 15 Pneumatic piping 16 Compressor 17 Pressure adjustment valve 18 Discharge piping 19 Bypass piping 20 Sludge tank 21 Drain pipe 22 Suction pipe F Face P Pressure gauges Pb1, Pb2 Branch connection point Pm Merging connection Points V1 to V7 First valve to seventh valve V8 Check valve (eighth valve)

Claims (2)

a first chamber formed between the cutter head and the bulkhead;
a mud feeding pipe that sends muddy water into the first chamber;
a mud drainage pipe that discharges muddy water stored in the first chamber to the outside together with excavated soil taken into the first chamber;
Compressed air and muddy water are accommodated and communicated with the first chamber by pressure regulating piping, and the muddy water flows back and forth between the first chamber and the first chamber via the pressure regulating piping. and a second chamber that alleviates fluctuations in mud water pressure,
The connection position of the pressure regulating pipe on the first chamber side is above the center of the partition wall in the height direction of the first chamber.
A mud water type shield excavator characterized by: The connection position of the mud feeding pipe on the first chamber side is above the connection position of the pressure regulating pipe in the partition wall.
The muddy water type shield excavator according to claim 1, characterized in that:

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