JP7449634B2 - Mud water type shield excavator and its excavation method - Google Patents

Description

The present invention relates to a muddy water type shield excavator that excavates a tunnel by applying a predetermined pressure to muddy water in a cutter chamber to stabilize a face and form a tunnel, and a method for excavating the same.

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.

In muddy shield tunneling machines, muddy water is constantly supplied into the cutter chamber from the mud pipe, and the muddy water pressure in the cutter chamber counteracts the pressure (earth pressure and water pressure) in front of the face. It's stabilized. 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 supplied to the cutter chamber is adjusted according to changes in the mud water pressure in the cutter chamber depending on the soil quality of the ground, and the mud supply pipe and mud drainage are adjusted. It is necessary to adjust the flow rate of the pipe. However, when the ground is complex or under high water pressure, the mud pressure inside the cutter chamber may change 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 sudden changes in mud water pressure by responding to changes in the water level of the mud water inside.

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 changes, 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 changes, 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.

Here, in Patent Document 3 (Japanese Unexamined Patent Publication No. 2003-120175) and Patent Document 4 (Japanese Patent Application Laid-Open No. 2008-248509), as in Patent Document 1, there is a A structure is disclosed in which two air chambers are provided and the entire chamber is divided vertically into two tanks. Patent Document 3 describes an invention in which the bottom plate of an air chamber connected to a cutter chamber is formed obliquely toward a muddy water supply port, and Patent Document 4 describes an invention in which a bottom plate of an air chamber connected to a cutter chamber is formed obliquely toward a muddy water supply port. An invention is described for cleaning the device from the inside.

JP2013-083110A Japanese Patent Application Publication No. 2002-180781 Japanese Patent Application Publication No. 2003-120175 Japanese Patent Application Publication No. 2008-248509

The techniques described in Patent Document 1 and Patent Document 2 have a structure in which muddy water is supplied from a first chamber (cutter chamber) to a separately provided second chamber (air chamber/pressure adjustment tank). Therefore, mud escapes from the cutter head and a large amount of muddy water is supplied from the second chamber into the first chamber, and when the muddy water in the second chamber is emptied, the pressure of the muddy water in the first chamber increases. There is a possibility that fluctuations cannot be sufficiently alleviated.

Here, in Patent Document 3 and Patent Document 4, a water level detection device (detector 14, level switch 22) is provided in the second chamber (air chamber 7, pressure adjustment chamber 6) to detect the amount of muddy water. , a technique is disclosed in which muddy water is supplied into a second chamber so that the muddy water surface has a predetermined pressure.

However, the techniques described in these patent documents merely supply muddy water into the second chamber, and the relationship between the amount of muddy water in the second chamber and the excavation of the muddy shield excavator is difficult. No consideration has been given to

The present invention has been made from the above-mentioned technical background, and an object of the present invention is to provide a technology that allows excavation to be carried out while adjusting the amount of muddy water in the second chamber provided in a muddy water type shield excavator. purpose.

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 on the back side of a cutter head for excavating a ground; and a muddy water shield excavator in the first chamber. a mud feeding pipe for feeding mud into the first chamber; 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; A second chamber is connected to the first chamber by a pressure piping, and muddy water flows back and forth between the first chamber and the first chamber via the pressure regulating piping to alleviate changes in muddy water pressure in the first chamber. a chamber, a bypass pipe that communicates the sludge pipe and the sludge removal pipe, a supply pipe that branches from the sludge pipe and is connected to the second chamber, and a supply pipe that extends from the second chamber and connects the sludge pipe to the second chamber; a first valve that opens and closes a pipe line closer to the first chamber than a branch connection point between a discharge pipe connected to the mud removal pipe and the bypass pipe in the mud feeding pipe; a second valve that opens and closes the pipeline on the side of the first chamber from the branch connection point with the bypass piping; a third valve that opens and closes the pipeline of the bypass piping; and a third valve that opens and closes the pipeline of the supply piping. a fourth valve installed in the second chamber, a fifth valve that opens and closes the pipeline of the discharge piping, a sixth valve that opens and closes the pipeline of the pressure regulation piping, and The upper limit water level at which muddy water in the second chamber needs to be discharged, the reference water level at the upper end and the lower end at which muddy water does not need to be supplied or discharged in the second chamber, and the water level at the lower end of the second chamber. a water level detection means for detecting a lower limit water level at which muddy water needs to be supplied into the chamber ; and a control means for controlling opening and closing of the first to sixth valves according to a detection result of the water level detection means; In the case of the upper limit water level, the control means opens the first valve, the second valve, the fifth valve, and the sixth valve, and also opens the third valve and the fourth valve. is closed and excavation is performed while draining mud until the inside of the second chamber reaches the reference water level at the upper end, and when the water level is within the range from the reference water level at the upper end to the reference water level at the lower end , the first valve, the second valve, and the sixth valve are opened, and the third valve, the fourth valve, and the fifth valve are closed to supply and drain sludge in the second chamber. If the lower limit water level is reached, the first valve, the second valve, the fourth valve, and the sixth valve are opened, and the third valve and the The present invention is characterized in that the fifth valve is closed and control is executed to perform excavation while supplying mud until the interior of the second chamber reaches the reference water level at the lower end .

In the muddy water type shield excavator of the present invention according to claim 2, in the invention according to claim 1, the water level detection means detects an excavation stop water level that is higher than the upper limit water level, and a water level that is higher than the lower limit water level. further detects an excavation stop water level which is a lower water level than the upper limit water level, and when the excavation stop water level is higher than the upper limit water level, the control means opens the third valve and the fifth valve. The first valve, the second valve, the fourth valve, and the sixth valve are closed to drain the mud until the inside of the second chamber reaches the upper limit water level, and then start digging. Sludge drainage is continued until the reference water level at the upper end is reached, and when the excavation stop water level is lower than the lower limit water level, the third valve and the fourth valve are opened, and the first valve is opened. , the second valve, the fifth valve, and the sixth valve are closed to supply mud until the inside of the second chamber reaches the lower limit water level, and then excavation is started, and the reference water level at the lower end is started. It is characterized by executing control to continue supplying mud until

The muddy water type shield excavator of the present invention according to claim 3 is the invention according to claim 1 or 2, wherein the control means controls the third valve prior to the control based on the detection result of the water level detection means. Then, while keeping the third valve open, open the sixth valve, and then excavate by opening only the first valve, the second valve, and the sixth valve. The method is characterized in that it executes control to start the process.

In the muddy water type shield excavator of the present invention according to claim 4, in the invention according to any one of claims 1 to 3, the water level detection means is arranged in a vertical direction on a side wall of the second chamber. It is characterized by a plurality of electrode sensors that are installed at a plurality of locations and detect the water level based on the presence or absence of energization due to muddy water.

In order to solve the above problems, an excavation method for a muddy shield excavator according to the present invention as set forth in claim 5 provides a first chamber formed on the back surface of a cutter head for excavating a ground; A mud pipe for feeding mud into the first chamber, a mud drainage pipe for discharging the mud accumulated in the first chamber to the outside along with the excavated soil taken into the first chamber, and compressed air and mud are accommodated. and is communicated with the first chamber by a pressure regulating pipe, and muddy water flows back and forth between the first chamber and the first chamber via the pressure regulating pipe to alleviate changes in muddy water pressure in the first chamber. a second chamber; a bypass pipe that communicates with the mud feeding pipe and the mud removal pipe; a supply pipe that branches from the mud feeding pipe and connects to the second chamber; a first valve that opens and closes a pipe on the side of the first chamber from a branch connection point between a discharge pipe extending and connected to the sludge drainage pipe and the bypass pipe in the sludge feeding pipe; a second valve that opens and closes a pipe on the side of the first chamber from a branch connection point with the bypass pipe in the pipe; a third valve that opens and closes the pipe of the bypass pipe; and a pipe of the supply pipe. a fourth valve that opens and closes the passage of the discharge piping, a fifth valve that opens and closes the passage of the pressure regulation piping, and a sixth valve that opens and closes the passage of the pressure regulation piping, installed in the second chamber, The water level of the second chamber is defined as an upper limit water level at which muddy water in the second chamber needs to be discharged, an upper reference water level and a lower end reference water level at which muddy water does not need to be supplied or discharged in the second chamber, and a water level detection means for detecting at the lower limit water level at which muddy water needs to be supplied into the second chamber , and when the detection result of the water level detection means is the upper limit water level, the first valve, the second , the fifth valve, and the sixth valve are opened, and the third valve and the fourth valve are closed to drain sludge until the inside of the second chamber reaches the reference water level at the upper end. If the detection result of the water level detection means is within the range from the reference water level at the upper end to the reference water level at the lower end , the first valve, the second valve, and the sixth valve are The valve is opened, and the third valve, the fourth valve, and the fifth valve are closed to perform excavation without supplying and draining mud in the second chamber, and the water level detection means When the detection result is the lower limit water level, the first valve, the second valve, the fourth valve, and the sixth valve are opened, and the third valve and the fifth valve are opened. It is characterized in that control is executed to perform excavation while closing the second chamber and supplying mud until the inside of the second chamber reaches the reference water level at the lower end.

According to a sixth aspect of the present invention, there is provided an excavation method for a mud shield excavator according to the present invention, in which the water level detection means detects an excavation stop water level that is a water level higher than the upper limit water level; further detecting an excavation stop water level that is a water level lower than the lower limit water level, and when the detection result of the water level detection means is the excavation stop water level that is higher than the upper limit water level, the third valve and the fifth the first valve, the second valve, the fourth valve, and the sixth valve are closed to drain mud until the inside of the second chamber reaches the upper limit water level. The excavation is started from , and mud removal is continued until the reference water level at the upper end is reached, and when the detection result of the water level detection means is the excavation stop water level lower than the lower limit water level, the third valve and The fourth valve is opened, and the first valve, the second valve, the fifth valve, and the sixth valve are closed to supply water until the inside of the second chamber reaches the lower limit water level. It is characterized in that control is executed to start excavation after filling with mud and to continue supplying mud until the reference water level at the lower end is reached .

An excavation method for a muddy shield excavator according to the present invention as set forth in claim 7 is, in the invention as set forth in claim 5 or 6, in which, prior to starting excavation based on the detection result of the water level detection means, only the third valve is , then open the sixth valve while keeping the third valve open, and then excavate by opening only the first valve, the second valve, and the sixth valve. characterized by starting.

According to the present invention, when the detection result of the water level detection means is the upper limit water level, only the first valve, the second valve, the fifth valve, and the sixth valve are opened and the inside of the second chamber is Digging is started by draining mud until it reaches the reference water level at the upper end , and if the detection result of the water level detection means is within the range from the reference water level at the upper end to the reference water level at the lower end , the first valve, the second valve, and When only the sixth valve is opened to perform excavation without supplying or discharging mud in the second chamber, and when the detection result of the water level detection means is the lower limit water level, the first valve and the second valve are opened. , only the fourth valve and the sixth valve are opened to supply mud until the inside of the second chamber reaches the reference water level at the lower end , and then excavation is started.

Thereby, it becomes possible to perform excavation while adjusting the amount of muddy water in the second chamber provided in the muddy water type shield excavator.

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. 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; FIG. 2 is an explanatory diagram showing the auxiliary chamber provided in the shield tunneling machine of FIG. 1 from the side. FIG. 2 is a diagram showing the water level in the auxiliary chamber provided in the shield tunneling machine of FIG. 1, the opening/closing states of first to sixth valves corresponding to the water level, and the operation contents. 2 is a flowchart showing control corresponding to the amount of muddy water in the auxiliary chamber during earth excavation in the shield excavator of FIG. 1. FIG.

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 water shield excavator according to an embodiment of the present invention from the side.

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, and is therefore 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 slipping, which causes a large amount of muddy water to flow 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.

In this embodiment, the cutter head 2 has a face plate type, and the front surface (the surface facing the face F) is equipped with a plurality of bits and scraper teeth (any of them) for crushing boulders etc. and excavating the ground. (not shown) is attached. Further, the cutter head 2 is formed with an earth and sand inlet (not shown) for taking in earth and sand excavated by the rotation of the cutter head 2 into the cutter chamber 4 .

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 is provided 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 (sludge discharge port) of the mud feeding pipe 5 passes through the upper part of the front surface of the partition wall 9 and reaches the cutter chamber 4 . Thereby, 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 tunneling machine 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 chamber is a muddy water layer (reserved muddy water). In this embodiment, the pressure regulating pipe 13 is connected to the cutter chamber 4 at a position above the center 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 its function, so it is desirable that the density of muddy water in the chamber is low. In other words, the muddy water in the cutter chamber 4 is thick near the bottom and becomes thinner toward the top. Therefore, when the pressure regulating pipe 13 is connected near the bottom of the cutter chamber 4, the muddy water has a high concentration, that is, contains a lot of earth and sand. Since muddy water easily flows into the auxiliary chamber 11, it is necessary to take in muddy water with a low concentration, so the connection position of the pressure regulating pipe 13 to the cutter chamber 4 is set as described above. However, depending on conditions such as muddy water concentration, the connection position of the pressure regulating pipe 13 to the cutter chamber 4 may be lower than the center of the cutter chamber 4.

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.

Further, as shown in the figure, 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. Furthermore, a relief valve (pressure control valve) 17 is attached to the upper surface of the auxiliary chamber 11 to maintain the air pressure in the chamber at a set value. 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 is controlled by the relief valve 17 so that the pressure inside the auxiliary chamber 11 is 0.3 MPa. Note that the opening degree of the relief 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 relief 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 according to changes 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 compressed air in the upper layer acts as a pneumatic damper and absorbs changes in the face pressure.

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.

Here, in this embodiment, there is only one pneumatic pipe 15. However, a plurality of pneumatic pipes 15 are provided, and normally only one pneumatic pipe 15 is required to supply compressed air from the receiver tank 14 to the auxiliary chamber 11, so that the pressure inside the auxiliary chamber 11 is reduced. If the pressure drops suddenly, other pneumatic pipes 15 are used to supply a large amount of compressed air into the auxiliary chamber 11 at the same time, so that the pressure in the auxiliary chamber 11 is quickly returned to a predetermined level. It's okay. Moreover, if a plurality of pneumatic pipes 15 are provided, even if one of the pneumatic pipes 15 has a problem, it becomes possible to take immediate action.

In addition, the compressed air supply means comprised of the receiver tank 14 and the compressor 16 is mounted on the following truck which moves forward following the forward movement of the shield excavator 1.

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.

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, a seventh valve V7 is attached to the drain pipe 21 that connects the auxiliary chamber 11 and the mud removal tank 20.

These first valves V1 to seventh valves V7 are for opening and closing their respective pipelines, and in this embodiment, they are used to control the working status of the shield excavator 1 (earth excavation work, data indicating that the mountain excavation work is stopped), the measured values by the pressure gauge and concentration meter of the muddy water in the cutter chamber 4, the measured values by the level checker 22, electrode sensor S and pressure gauge in the auxiliary chamber 11, etc. Based on this, the opening and closing operations are automatically performed by an actuator such as a motor controlled by a control section (control means) not shown.

However, the operator may open and close the first valve V1 to the seventh valve V7 via actuators without providing a control unit. Further, opening adjustment valves may be used for the first valve V1 to the seventh valve V7 to enable more precise operation.

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.

Note that, as described above, in this embodiment, the mud removal tank 20 is connected to the bottom surface of the auxiliary chamber 11 via the 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) and is 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.

As shown in FIG. 4, within the auxiliary chamber 11, electrode sensors (water level detection means) S are installed at seven locations (electrode sensors S1 to S7) in the vertical direction on the side wall of the auxiliary chamber 11. In addition, here, the electrode sensor at the top is designated as S1, and the electrode sensors are designated as S2, S3, S4, S5, S6, and S7 downward from there.

Now, this electrode sensor S is equipped with two electrodes that are separated through an insulator and whose tips face the inside of the auxiliary chamber 11, and by detecting the presence or absence of current between these electrodes, , it is detected whether muddy water is present even at the sensor S (if the current is applied, muddy water is present). As mentioned above, since the electrode sensors S are installed at seven locations in the vertical direction on the side wall of the auxiliary chamber 11, the water level (H) in the auxiliary chamber 11 can be determined depending on which electrode sensors S are energized. Can be detected.

As shown in FIG. 4, the positions of the respective electrode sensors S1 to S7 for measuring the water level (H) correspond to levels L1 to L7 in the auxiliary chamber 11. For example, if the electrode sensors S3 to S7 are energized, the water level in the auxiliary chamber 11 will be at the level L3 corresponding to the position of the electrode sensor S3. Note that the intervals between the plurality of electrode sensors (electrode sensors S1 to S7) may not be equal.

Here, as shown in FIG. 5, the levels L1 to L7 corresponding to the water level in the auxiliary chamber 11 have the following contents.

That is, the level L1 is the level of the excavation stop water level (abnormally high level), and the bypass circulation mode is set in which muddy water circulates through the bypass pipe 19 (in other words, without passing through the cutter chamber 4), and the sixth valve V6 The operation is to close the tank and discharge muddy water to level L2. Note that since the level L1 is in the bypass circulation mode, the excavation is stopped (emergency stop) until the level L1 is exited. Level L2 is the upper limit water level, and when the water level drops to this level, the cutter chamber circulation mode is set in which the muddy water circulates through the cutter chamber 4 (in other words, without passing through the bypass pipe 19), and the muddy water is discharged to level L3. This is the action of excavating while continuing. Level L3 is the level of the reference water level (upper end), and the cutter chamber circulation mode is set, and the supply and removal of mud to the auxiliary chamber 11 (sludge supply from the supply pipe 12, mud removal from the discharge pipe 18) is not performed. This is the operation content of excavating without digging. Level L4 is the reference water level, level L5 is the reference water level (lower end), and the operation content is the same as level L3. Level L6 is the lower limit water level, and the operation content is to set the cutter chamber circulation mode and supply muddy water up to level L5 to execute excavation. The level L7 is an excavation stop water level (abnormally high level), and is an operation to set the bypass circulation mode and close the sixth valve V6 to supply muddy water up to the level L6. Note that since level L7 is also in the bypass recirculation mode, excavation is stopped (emergency stop) until exiting level L7. Note that level L6 is the lower limit water level, and when the water level rises to this level, the cutter chamber circulation mode is set and excavation is executed while continuing to supply muddy water up to level L5.

In the cutter chamber circulation mode, the mud pump 8 supplies the mud water stored in the mud water plant 7 through the mud pipe 5 into the cutter chamber 4, and the mud pressure in the cutter chamber 4 is adjusted to the earth pressure at the face F and the mud water pressure in the cutter chamber 4. In addition to stabilizing the face F at a pressure commensurate with the groundwater pressure, the muddy water accumulated in the cutter chamber 4 is transported along with the excavated soil taken into the cutter chamber 4 through the muddy water plant 7 outside the tunnel by the mud draining pipe 6. A tunnel is formed in the ground while circulating the water. 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. .

Here, in FIG. 5, the opening and closing of the first valve V1 to the sixth valve V6 are illustrated, but the details will be explained in conjunction with the flowchart described later.

In this embodiment, the water level is detected in seven levels from level Ll to level L7 by the electrode sensors S1 to S7, but it may be higher or lower than these levels. That is, at least three electrode sensors S may be provided so that three types of water levels, an upper limit water level, a reference water level, and a lower limit water level, can be detected. As shown in this embodiment, the reference water level includes level L3: reference water level (upper end), level L4: reference water level, and level L5: reference water level (lower end) to widen the water level width that becomes the reference water level. If a single standard water level is used, it is desirable to widen the width of the water level as shown in the figure. Further, the excavation stop water level (abnormally high level) and the excavation stop water level (abnormally high level) may not be detected. This is because if the upper limit water level and the lower limit water level are set to, for example, the upper and lower end levels of the reference water level, the risk of reaching the excavation stop water level (abnormally high level) or the excavation stop water level (abnormally high level) can be almost ignored.

Further, for example, when excavating a stratum with extremely large sludge loss, the emergency stop work may be started when the water level in the auxiliary chamber 11 falls to level L8 in the ninth stage. In particular, when the auxiliary chamber 11 has a vertically elongated shape and a small capacity, it is effective to detect the water level in multiple stages.

A level checker (flow direction detection means) 22 is installed in the auxiliary chamber 11 . In the present embodiment, a guide pulse type level checker 22 is used that measures the water surface height from the time of the pulse signal transmitted on the guide probe from the time it is transmitted until it is reflected on the water surface and received. This level checker 22 detects 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. It is for.

In the shield excavator 1 having the above configuration, the flow of muddy water due to opening and closing of the first valve V1 to the seventh valve V7 according to the water level of the auxiliary chamber 11 will be explained using FIGS. 2 to 6. . Note that the first valve V1 to the seventh valve V7, which open and close the pipes to control the flow of muddy water, are controlled by the control section as described above. Further, the seventh valve V7 is opened and closed to discharge muddy water from the auxiliary chamber 11, and has the same function as the fifth valve V5, but in order to avoid complicating the explanation, The explanation of the operation of the seventh valve V7 will be simplified.

That is, when mud removal from the auxiliary chamber 11 is stopped, the fifth valve V5 and the seventh valve V7 are both closed, whereas when mud removal from the auxiliary chamber 11 is stopped, the fifth valve V5 and the seventh valve V7 are closed. This is done by opening one or both of the valves V7. Therefore, when the auxiliary chamber 11 is not drained, both the fifth valve V5 and the seventh valve V7 are in the closed position, but when the auxiliary chamber 11 is to be drained, the fifth valve V5 is in the open position and the seventh valve V7 is in the closed position. There are three patterns: the seventh valve V7 is in the closed position, the fifth valve V5 is in the closed position and the seventh valve V7 is in the open position, and both the fifth valve V5 and the seventh valve V7 are in the open position.

Therefore, when either or both of the fifth valve V5 of the discharge pipe 18 and the seventh valve V7 of the drain pipe 21 are provided, the fifth valve V5 of the discharge pipe 18 and the seventh valve V7 of the drain pipe 21 are provided. The fact that the fifth valve V5 is in the closed position (CL (Close)) means that the seventh valve V7 is also in the closed position, and the fact that the fifth valve V5 is in the open position (OP (Open)) means that the seventh valve V7 is also in the closed position. This means that one or both of the fifth valve V5 and the seventh valve V7 are in the open position.

Here, in FIGS. 2 and 3, 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. 2 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).

In addition, in the flowchart of FIG. 6, as described in the figure, V1 to V6 indicate the first to sixth valves, OP (Open) indicates that the valve V is in the open position, and CL (Close) indicates that the valve V is in the open position. ) indicates that valve V is in the closed position, and bypass recirculation mode is a mode in which the first valve V1 is CL, the second valve V2 is CL, and the third valve V3 is OP (that is, muddy water is bypassed). The cutter chamber circulation mode is a mode in which the first valve V1 is OP, the second valve V2 is OP, and the third valve V3 is CL (that is, the muddy water is circulated through the cutter chamber). H refers to the water level in the auxiliary chamber 11 measured by the electrode sensors S1 to S7, and L1 to L7 refer to the water level H in the auxiliary chamber 11, respectively.

Now, in FIG. 6, first, the muddy shield excavator 1 is put into the bypass recirculation mode (FIG. 3), and only the third valve V3 is opened (step St01), and then, the third valve V3 is left open. The sixth valve V6 is opened (Step St02), and then the cutter chamber circulation mode (Fig. 2) is entered and only the first valve V1 and the second valve V2 are opened (Step St03). (Step St04). At this time, since the sixth valve V6 provided in the pressure regulating pipe 13 is opened in step St02, the first valve V1 is opened in the cutter chamber circulation mode in step St03, and the flow from the slurry pipe 5 to the cutter chamber is opened. When muddy water flows into the cutter chamber 4 all at once, the muddy water flows into the auxiliary chamber 11 via the pressure regulating pipe 13, and the water level in the auxiliary chamber 11 to which compressed air is supplied rises, causing an increase in the water pressure in the cutter chamber 4. As a result, the sudden load on the cutter head 2 is reduced.

Once excavation is started in step St04, water level measurement is performed next (step St05).

Further, in this embodiment, step St05 is executed after steps St01 to St04, but since a certain amount of muddy water has already entered the auxiliary chamber 11, steps St01 to St04 may be omitted. good. However, for smooth operation of the shield tunneling machine 1, it is desirable to execute steps St01 to St04.

Now, returning to FIG. 6, it is determined whether or not the water level H in the auxiliary chamber 11 is lower than the level L7 as a result of the water level measurement in step St05 (step St06). If it is determined in step St06 that the water level H in the auxiliary chamber 11 is not less than (more than) the level L7, then it is determined whether the water level H in the auxiliary chamber 11 is greater than the level L1 ( Step St07).

Thus, in steps St06 and St07, it is determined whether the water level H in the auxiliary chamber 11 is in a state exceeding the excavation stop water level (level L7: abnormally low level, level L1: abnormally high level). The fact that "NO" is determined in both steps St06 and St07 means that the water level H in the auxiliary chamber 11 has not exceeded the excavation stop water level.

Now, if it is determined in step St07 that the water level H in the auxiliary chamber 11 is not more than (less than) the level L1, then it is determined whether the water level H in the auxiliary chamber 11 is less than the level L6 ( Step St08). If it is determined in step St08 that the water level H in the auxiliary chamber 11 is not less than (more than) the level L6, then it is determined whether the water level H in the auxiliary chamber 11 is greater than the level L2 ( Step St09).

Thus, in steps St08 and St09, it is determined whether the water level H in the auxiliary chamber 11 is in a state exceeding the upper and lower limit water levels (level L2: upper limit water level, level L6: lower limit water level). The fact that the determination in both steps St08 and St09 is "NO" means that the water level H in the auxiliary chamber 11 does not exceed the upper or lower limit water levels.

Therefore, since the determination in steps St06 to St09 is "NO", the water level H in the auxiliary chamber 11 is within the standard water level, that is, the level H is within the standard water level, that is, the level L3 (standard water level (upper limit)) L4 (standard water level)), or level L4 (standard water level) to level L5 (standard water level (lower limit))). Therefore, the excavation by the shield excavator 1 (step St04) started under the cutter chamber circulation mode (step St03) continues to be executed. That is, in response to fluctuations in the muddy water pressure within the cutter chamber 4, muddy water flows back and forth between the cutter chamber 4 and the auxiliary chamber 11 via the pressure regulating pipe 13, and the pressure fluctuations within the cutter chamber 4 are alleviated. The ground is being excavated.

Then, in step St10, it is determined whether the propulsion jack is fully extended, and if it is determined that it is fully extended, the bypass circulation mode is set (step St11), and the excavation of the shield excavator 1 is stopped (step St12). Then, in order to construct a tunnel, segments (not shown) are assembled into a ring shape (step St13).

Note that if it is determined in step St10 that the propulsion jack is not fully extended, it is necessary to move the shield excavator 1 further forward, so the process returns to step St05 described above.

When the assembly of the segments is completed in step St13, it is determined in step St44 whether or not the day's work has been completed, and if it is determined that the work has been completed, the fourth valve V4 and the fifth valve V5 are and closes the sixth valve V6 (step St45). Further, if it is determined in step St44 that the work for the day has not been completed, the process returns to step St03 described above.

Now, if the water level H in the auxiliary chamber 11 is always within the standard water level, the steps from step St01 to step St13 as described above can be sequentially passed through, and smooth excavation can be performed. However, since the amount of drilling mud flowing into the cutter chamber 4 varies depending on the ground condition, the mud in the auxiliary chamber 11 is moved back and forth between the cutter chamber 4 and the mud water pressure in the cutter chamber 4. It is easing change. Therefore, the water level H in the auxiliary chamber 11 is not necessarily always within the standard water level.

For this reason, as shown in this flowchart, the water level H in the auxiliary chamber 11 is checked as appropriate, and processing is executed in accordance with the check results.

Now, as a check of the water level H of the auxiliary chamber 11, if it is determined in the above-mentioned step St06 that the water level H of the auxiliary chamber 11 is lower than the level L7 (excavation stop water level (abnormally low level)), According to the level L7 of No. 5, the shield tunneling machine 1 stops digging (step St14), and the first valve V1 to the sixth valve V6 are brought into a state corresponding to the level L7. That is, after opening the fourth valve V4 and closing the fifth valve V5 and the sixth valve V6 (step St15), the bypass recirculation mode is set (step St16). As a result, muddy water starts to be supplied from the mud feeding pipe 5 to the auxiliary chamber 11 through the supply pipe 12 (Step St17).

In the bypass circulation mode, muddy water is supplied into the auxiliary chamber 11 (step St17 and step St33 described later) or muddy water is discharged (step St26 and step St39 described later). Therefore, the branch connection point Ps of the supply pipe 12 with the mud feed pipe 5 and the confluence connection point Pm of the discharge pipe 18 with the mud removal pipe 6 are the same as the branch connection point Pb1 of the mud feed pipe 5 with the bypass pipe 19, It is preferable that the mud pipe 6 be installed closer to the starting well entrance than the branch connection point Pb2 with the bypass pipe 19 (see FIGS. 1 to 3).

Then, water level measurement similar to step St05 is performed (step St18), and it is determined whether the water level H in the auxiliary chamber 11 is higher than level L6 (lower limit water level) (step St19). If it is determined that the amount is higher than the level L6, the first valve V1 to the sixth valve V6 are set to the state according to the level L6 in FIG. That is, after opening the fourth valve V4 and the sixth valve V6 and closing the fifth valve V5 (step St20), the cutter chamber circulation mode is set (step St21). As a result, muddy water is supplied from the mud feeding pipe 5 to the auxiliary chamber 11 through the supply pipe 12, and the pressure regulating pipe 13 is opened, so that the shield excavator 1 starts digging (step St22). Note that after the start of excavation, the process moves to step St34, which will be described later.

Note that, in step St19, if it is determined that the water level H in the auxiliary chamber 11 is not higher than (less than) the level L6, mud supply is performed until the water level H becomes higher than the level L6.

Next, if it is determined that the water level H in the auxiliary chamber 11 is higher than the level L1 (excavation stop water level (abnormally high level)) in the above-mentioned step St07, the shield excavator 1 is stopped to excavate according to the level L1 in FIG. The operation is stopped (step St23), and the first valve V1 to the sixth valve V6 are brought into a state corresponding to the level L1. That is, after closing the fourth valve V4 and the sixth valve V6 and opening the fifth valve V5 (step St24), the bypass recirculation mode is set (step St25). As a result, mud supply to the auxiliary chamber 11 is stopped, and muddy water in the auxiliary chamber 11 starts to be discharged to the mud removal pipe 6 via the discharge pipe 18 (Step St26).

Then, water level measurement similar to step St05 is performed (step St27), and it is determined whether the water level H in the auxiliary chamber 11 has become lower than level L2 (upper limit water level) (step St28). If it is determined that the level has become lower than the level L2, the first valve V1 to the sixth valve V6 are set to the state according to the level L2 in FIG. 5. That is, after closing the fourth valve V4 and opening the fifth valve V5 and the sixth valve V6 (step St29), the cutter chamber circulation mode is set (step St30). As a result, muddy water is discharged from the auxiliary chamber 11 from the discharge pipe 18 to the mud removal pipe 6, and the pressure regulation pipe 13 is opened, and the shield excavator 1 starts digging (Step St31). Note that after the start of excavation, the process moves to step St40, which will be described later.

Note that, in step St28, if it is determined that the water level H in the auxiliary chamber 11 has not become less than (is more than) the level L2, mud removal is performed until it becomes less than the level L2.

Next, in step St08, if it is determined that the water level H is lower than the level L6 (lower limit water level), the first valve V1 to the sixth valve V6 are adjusted to correspond to the level L6 according to the level L6 in FIG. state. That is, the fourth valve V4 and the sixth valve V6 are opened, the fifth valve V5 is closed (step St32), and mud supply into the auxiliary chamber 11 is started (step St33).

Then, water level measurement similar to step St05 is performed (step St34), and it is determined whether the water level H in the auxiliary chamber 11 has become higher than level L5 (reference water level (lower end)) (step St35). If it is determined that the level has become higher than the level L5, the first valve V1 to the sixth valve V6 are set to the state according to the level L5 in FIG. 5. That is, after closing the fourth valve V4 and the fifth valve V5 and opening the sixth valve V6 (step St36), the supply of mud to the auxiliary chamber 11 is stopped (step St37). Note that the reason why the supply of mud to the auxiliary chamber 11 is stopped is because the inside of the auxiliary chamber 11 has reached the reference water level. Further, if the slurry supply is stopped in step St37, the process returns to step St05 described above.

In addition, in step St35, if it is determined that the water level H of the auxiliary chamber 11 has not increased (less than) the level L5, mud supply is performed until the water level H increases.

Next, in step St09, if it is determined that the water level H is higher than the level L2 (upper limit water level), the first valve V1 to the sixth valve V6 are adjusted to correspond to the level L2 according to the level L2 in FIG. state. That is, the fourth valve V4 is closed, the fifth valve V5 and the sixth valve V6 are opened (step St38), and mud removal from the auxiliary chamber 11 is started (step St39).

Then, water level measurement similar to step St05 is performed (step St40), and it is determined whether the water level H in the auxiliary chamber 11 has become lower than the level L3 (reference water level (upper end)) (step St41). If it is determined that the level has become lower than the level L3, the first valve V1 to the sixth valve V6 are set to the state according to the level L3 in FIG. 5. That is, after closing the fourth valve V4 and the fifth valve V5 and opening the sixth valve V6 (step St42), the draining of mud from the auxiliary chamber 11 is stopped (step St43). Note that the reason why mud removal from the auxiliary chamber 11 is stopped is because the inside of the auxiliary chamber 11 has reached the reference water level. Moreover, if mud removal is stopped in step St43, the process returns to step St05 described above.

Note that, in step St41, if it is determined that the water level H in the auxiliary chamber 11 is higher than the level L3, mud removal is performed until it becomes lower.

Here, as shown in FIG. 5, opening and closing of the first valve V1 to the sixth valve V6 at level L3 (reference water level (upper end)), level L4 (reference water level), and level L5 (reference water level (lower end)) All positions are the same. In the above description of FIG. 6, there is no process to "set the first valve V1 to the sixth valve V6 in accordance with the level L4 (reference water level) of FIG. 5." This means that if it is determined that the water level in the auxiliary chamber 11 is higher than the level L6 (lower limit water level) in step St08 and lower than the level L2 (upper limit water level) in step St09, that is, the water level in the auxiliary chamber 11 is If it is between level L3 and level L5 (reference water level (upper end) and reference water level (lower end)), there is no need to change the opening and closing positions of the first valve V1 to sixth valve V6. is higher (or lower) than level L4 (reference water level)" and "the first valve V1 to sixth valve V6 are brought into a state according to level L4 (reference water level) in FIG. 5." This is because there is no need to perform any processing. However, it is also possible to perform processing related to whether the water level H is higher or lower than the level L4.

As explained above, according to the present embodiment, when the detection result of the electrode sensor S is the upper limit water level L2, the first valve V1, the second valve V2, the fifth valve V5, and the Only the valve V6 of No. 6 is opened to drain mud and start digging until the inside of the auxiliary chamber 11 reaches the reference water level L3, and if the detection result of the electrode sensor S is the reference water level L3 to L5, Only the first valve V1, the second valve V2, and the sixth valve V6 are opened to perform excavation without supplying and draining mud in the auxiliary chamber 11, and the detection result of the electrode sensor S is at the lower limit water level. In the case of L6, only the first valve V1, the second valve V2, the fourth valve V4, and the sixth valve V6 are opened and mud is supplied until the inside of the auxiliary chamber 11 reaches the reference water level and excavation is continued. I'm trying to start.

Therefore, it becomes possible to perform excavation while adjusting the amount of muddy water in the auxiliary chamber 11 provided in the muddy water type shield excavator 1.

In this embodiment, as described above, whether or not the cutter chamber 4 is in the sludge loss state is determined from the calculation result of the sludge amount.

Specifically, the concentration of muddy water in the cutter chamber 4 in the muddy state is adjusted as follows. That is, when the amount of sludge lost per day (=(sludge feeding amount + excavated soil amount) - sludge amount) is 10% or more of the total amount, it is defined as 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.

Further, contrary to the slippage, the water pressure at the face F may become high, and groundwater may flow into the cutter chamber 4 and the water level may 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 an earth pressure meter (not shown), 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.

Note that when the muddy water in the auxiliary chamber 11 drops to, for example, level L6, the muddy water concentration is increased and the muddy water is supplied to the auxiliary chamber 11, but the water level in the auxiliary chamber 11 still moves back and forth between the level L6 and the level L5. If this continues for several days (for example, 2 or 3 days), the administrator can take measures such as changing the reference water level (lower end) to level L4.

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.

For example, the water level detection means is not limited to the electrode sensor S that detects the water level based on the presence or absence of electricity due to muddy water as in this embodiment, but can be any of various types having a function of detecting the water level in the auxiliary chamber 11. things can be applied. Therefore, the installation location may not be on the side wall of the auxiliary chamber 11 but inside.

Further, the flow direction detection means is not limited to the guide pulse type level checker 22 as in this embodiment, and may be a hydraulic type, an ultrasonic type, a radio wave type, a float type, an optical type, etc. . Furthermore, instead of the level checker 22, a flow direction meter (flow direction detection means) 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.

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 regulation piping 14 Receiver tank 15 Pneumatic piping 16 Compressor 17 Relief valve (pressure control valve)
18 Discharge piping 19 Bypass piping 20 Sludge tank 21 Drain pipe 22 Level checker (flow direction detection means)
F Face H Water level in the auxiliary chamber Pb1, Pb2 Branch connection point Pm Merging connection point S, S1 to S7 Electrode sensor (water level detection means)
L1 to L7 Levels for the water level in the auxiliary chamber V1 to V7 First valve to seventh valve V8 Check valve (eighth valve)

Claims (7)

a first chamber formed on the back of a cutter head for excavating the earth;
a mud feeding pipe that sends muddy water into the first chamber;
a mud draining 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. a second chamber for mitigating changes in mud water pressure;
a bypass pipe that communicates the sludge feeding pipe and the sludge removal pipe;
a supply pipe branched from the mud feeding pipe and connected to the second chamber;
a discharge pipe extending from the second chamber and connected to the mud removal pipe;
a first valve that opens and closes a pipe line closer to the first chamber than a branch connection point with the bypass pipe in the mud feeding pipe; a second valve that opens and closes the pipeline on the chamber side of the first chamber;
a third valve that opens and closes the pipeline of the bypass piping;
a fourth valve that opens and closes the conduit of the supply piping; and a fifth valve that opens and closes the conduit of the discharge piping;
a sixth valve that opens and closes the pipeline of the pressure regulating piping;
installed in the second chamber, and sets the water level of the second chamber to an upper limit water level at which muddy water in the second chamber needs to be discharged, and an upper end water level at which muddy water in the second chamber does not need to be supplied or discharged. water level detection means for detecting at a reference water level, a reference water level at a lower end, and a lower limit water level at which muddy water needs to be supplied into the second chamber ;
control means for controlling opening and closing of the first to sixth valves according to the detection results of the water level detection means;
The control means includes:
In the case of the upper limit water level, the first valve, the second valve, the fifth valve, and the sixth valve are opened, and the third valve and the fourth valve are closed. Executing excavation while removing mud until the inside of the second chamber reaches the reference water level at the upper end ,
If the water level is within the range from the reference water level at the upper end to the reference water level at the lower end , the first valve, the second valve, and the sixth valve are opened, and the third valve and the fourth valve are opened. performing excavation without supplying and draining mud in the second chamber by closing the valve and the fifth valve ;
In the case of the lower limit water level, the first valve, the second valve, the fourth valve, and the sixth valve are opened, and the third valve and the fifth valve are closed. Executing control to perform excavation while supplying mud until the inside of the second chamber reaches the reference water level at the lower end ;
A mud water type shield excavator characterized by: The water level detection means further detects an excavation stop water level that is a water level higher than the upper limit water level, and an excavation stop water level that is a water level lower than the lower limit water level,
The control means includes:
When the excavation stop water level is higher than the upper limit water level, the third valve and the fifth valve are opened, and the first valve, the second valve, the fourth valve, and the Closing the sixth valve and draining the inside of the second chamber until the water level reaches the upper limit water level, and then starting digging and continuing draining mud until the water level reaches the reference water level at the upper end ;
When the excavation stop water level is lower than the lower limit water level, the third valve and the fourth valve are opened, and the first valve, the second valve, the fifth valve, and the Closing the sixth valve and supplying mud until the inside of the second chamber reaches the lower limit water level, and then starting excavation and executing control to continue supplying mud until the water level reaches the reference water level at the lower end ;
The muddy water type shield excavator according to claim 1, characterized in that: The control means includes:
Prior to control based on the detection result of the water level detection means,
Open only the third valve, then open the sixth valve while keeping the third valve open, then only the first valve, the second valve, and the sixth valve. Execute control to release and start digging,
The muddy water type shield excavator according to claim 1 or 2, characterized in that: The water level detection means is a plurality of electrode sensors that are installed at a plurality of locations in the vertical direction on the side wall of the second chamber and detect the water level based on the presence or absence of electricity due to muddy water.
The mud water type shield excavator according to any one of claims 1 to 3, characterized in that: a first chamber formed on the back of a cutter head for excavating the earth;
a mud feeding pipe that sends muddy water into the first chamber;
a mud draining 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. a second chamber for mitigating changes in mud water pressure;
a bypass pipe that communicates the sludge feeding pipe and the sludge removal pipe;
a supply pipe branched from the mud feeding pipe and connected to the second chamber;
a discharge pipe extending from the second chamber and connected to the mud removal pipe;
a first valve that opens and closes a pipe line closer to the first chamber than a branch connection point with the bypass pipe in the mud feeding pipe; a second valve that opens and closes the pipeline on the chamber side of the first chamber;
a third valve that opens and closes the pipeline of the bypass piping;
a fourth valve that opens and closes the pipeline of the supply piping; and a fifth valve that opens and closes the pipeline of the discharge piping;
a sixth valve that opens and closes the pipe line of the pressure regulating pipe;
installed in the second chamber, and sets the water level of the second chamber to an upper limit water level at which muddy water in the second chamber needs to be discharged, and an upper end water level at which muddy water in the second chamber does not need to be supplied or discharged. A reference water level, a reference water level at a lower end, and water level detection means for detecting at a lower limit water level at which muddy water needs to be supplied into the second chamber ,
When the detection result of the water level detection means is the upper limit water level, the first valve, the second valve, the fifth valve, and the sixth valve are opened, and the third valve and the Closing a fourth valve and excavating while draining mud until the interior of the second chamber reaches the reference water level at the upper end ;
When the detection result of the water level detection means is within the range from the reference water level at the upper end to the reference water level at the lower end , the first valve, the second valve, and the sixth valve are opened, and the third valve is opened. performing excavation without performing mud supply and drainage in the second chamber by closing the third valve, the fourth valve, and the fifth valve ;
When the detection result of the water level detection means is the lower limit water level, the first valve, the second valve, the fourth valve, and the sixth valve are opened, and the third valve and the executing control to execute excavation while supplying mud until the inside of the second chamber reaches the reference water level at the lower end by closing the fifth valve ;
An excavation method using a muddy water type shield excavator, which is characterized by the following. The water level detection means further detects an excavation stop water level that is a water level higher than the upper limit water level, and an excavation stop water level that is a water level lower than the lower limit water level,
If the detection result of the water level detection means is the excavation stop water level higher than the upper limit water level, the third valve and the fifth valve are opened, and the first valve and the second valve are opened. , close the fourth valve and the sixth valve to drain the inside of the second chamber until the water level reaches the upper limit water level, and then start digging and drain the mud until the upper limit water level is reached. continue,
If the detection result of the water level detection means is the excavation stop water level lower than the lower limit water level, the third valve and the fourth valve are opened, and the first valve and the second valve are opened. , close the fifth valve and the sixth valve, supply mud until the inside of the second chamber reaches the lower limit water level, and then start digging and supply mud until the water level reaches the lower limit reference water level. carry out continuous control;
6. An excavation method using a muddy shield excavator according to claim 5. Prior to the start of excavation based on the detection result of the water level detection means,
Open only the third valve, then open the sixth valve while keeping the third valve open, then only the first valve, the second valve, and the sixth valve. release and start digging,
7. An excavation method using a muddy shield excavator according to claim 5 or 6.

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