JP7481080B2 - Slurry shield tunneling machine - Google Patents

Description

The present invention relates to a mud shield machine that excavates the ground and forms a tunnel while stabilizing the tunnel face by applying a predetermined pressure to the mud in the cutter chamber.

In the shield tunneling method for building tunnels underground, the shield tunneling machine is assembled in the starting shaft and then launched to excavate underground. Once it reaches the destination shaft, the shield tunneling machine is disassembled in the destination shaft and transported to the surface.

Shield tunneling machines used in the shield method include mud pressure shield tunneling machines, which excavate the ground while stabilizing the face by turning the excavated soil into mud and applying a certain pressure, and mud water shield tunneling machines, which excavate the ground while stabilizing the face by applying a certain pressure to the mud water in the cutter chamber.

In a mud shield machine, mud is constantly supplied from the mud supply pipe into the cutter chamber, and the mud pressure in the cutter chamber is measured and managed with a pressure gauge. The mud pressure in the cutter chamber is made slightly higher than the pressure (earth pressure and water pressure) in front of the face, and the mud pressure in the cutter chamber counters the pressure in front of the face, stabilizing the face. During excavation, the mud stored in the cutter chamber is discharged to the outside from the mud discharge pipe together with the excavated soil taken into the cutter chamber (excavation mode). When excavation is suspended, such as during segment assembly, a valve (bypass valve) installed in the bypass pipe connecting the mud supply pipe and the mud discharge pipe is opened, and valves (mud supply valve and mud discharge valve) installed on the cutter head side of the bypass pipe of the mud supply pipe and the mud discharge pipe are closed to circulate the mud with the cutter chamber isolated (bypass mode). Furthermore, when the assembly of the segments is complete and drilling is resumed, the bypass valve is closed and the mud feed valve and mud discharge valve are opened.

The cutter head has a gap to allow the excavated soil and sand to enter the cutter chamber, and the mud in the cutter chamber presses down on the ground at the face. The mud supplied to the cutter chamber contains bentonite and polymer additives mixed into the mud, which forms a film (mud film) on the face to counter the pressure in front of the face. In ground that is sandy and water easily drains, the amount of mud flowing in is large (lost mud state), so the mud and polymer additives in the mud are increased, the amount of mud supplied is increased, and the amount of mud discharged is increased to stabilize the pressure in the cutter chamber. In ground that is clayey and water does not easily drain, the opposite operation is performed.

When excavating with a mud shield machine, it is necessary to adjust the concentration of the mud supplied to the cutter chamber in response to fluctuations in the mud pressure inside the cutter chamber due to the soil quality of the ground, as well as to adjust the flow rate of the mud supply pipe and the mud discharge pipe. However, in complex ground or under high water pressure, the mud pressure inside the cutter chamber can fluctuate suddenly, and if such concentration and flow rate adjustments cannot be made in time, this can have a negative impact on the ground and may even cause collapse.

In addition, when switching from bypass mode to drilling mode, the valves are closed and opened instantaneously, causing large fluctuations in the mud pressure in the cutter chamber, which can have a detrimental effect on the face, cutter head, mud transport pipes, and mud discharge pipes.

Therefore, Patent Document 1 (JP 2013-083110 A) and Patent Document 2 (JP 2002-180781 A) propose a technology that provides a chamber that utilizes the elasticity of compressed air, separate from the cutter chamber, to respond to fluctuations in the muddy water level in the cutter chamber and mitigate sudden fluctuations in muddy water pressure.

Specifically, the technology described in Patent Document 1 has a structure in which a second chamber, the air chamber, is provided behind the first chamber, the cutter chamber, making the entire chamber into two vertical tanks. The rear air chamber is connected to the cutter chamber at the bottom to receive muddy water, and connected to a compressor at the top to receive compressed air. When the pressure on the cutter chamber fluctuates, the water level in the air chamber rises and falls, but compressed air is supplied or discharged in response, mitigating the pressure fluctuations of the muddy water in the cutter chamber.

The technology described in Patent Document 2 has a structure in which a second chamber, a pressure adjustment tank, is provided in a tunnel separate from the first chamber, the cutter chamber. The lower part of the pressure adjustment tank is connected to the cutter chamber to receive muddy water, and the upper part is connected to a damper tank containing compressed air to receive compressed air. When the pressure on the cutter chamber fluctuates, the water level in the pressure adjustment tank rises and falls, but compressed air is supplied or discharged accordingly, mitigating the pressure fluctuations of the muddy water in the cutter chamber.

JP 2013-083110 A JP 2002-180781 A

In this way, in a mud shield tunneling machine that is provided with a first chamber (cutter chamber) and a second chamber (air chamber/pressure adjustment tank) that contains compressed air and mud and is connected to the first chamber, if the air pressure in the second chamber is not maintained at a set value, it will be impossible to mitigate sudden fluctuations in mud pressure in the first chamber.

The present invention was made in light of the above technical background, and aims to provide a slurry shield tunneling machine that can stably maintain the air pressure in the second chamber at a set value.

In order to solve the above problems, the muddy shield machine of the present invention described in claim 1 comprises a first chamber formed between a cutter head and a partition wall, a mud feed pipe for feeding muddy water into the first chamber, a mud discharge pipe for discharging the muddy water stored in the first chamber together with the excavated soil taken into the first chamber to the outside, a second chamber which contains compressed air and muddy water and is connected to the first chamber by a pressure regulating pipe, the muddy water passing between the first chamber and the second chamber via the pressure regulating pipe to reduce fluctuations in the muddy water pressure in the first chamber, and The system comprises compressed air supply means for supplying constant pressure compressed air, pressure adjustment means which are installed in the second chamber and constantly operating, each capable of independently maintaining the air pressure in the second chamber at a set value, and which cooperate to discharge the compressed air in the second chamber to maintain the air pressure in the second chamber at a set value , and detection means which are installed in each pipe in which the pressure adjustment means is installed, and which detect the state of the pressure adjustment means or the flow rate of compressed air flowing in the pipe, and by comparing the detection results of each detection means, it is possible to find any pressure adjustment means which has a malfunction .

The muddy water shield tunneling machine of the present invention described in claim 2 is characterized in that, in the invention described in claim 1 , the pneumatic piping is arranged in parallel with each other and each has the capacity to allow compressed air of a predetermined pressure to flow from the compressed air supply means into the second chamber, and the pipeline is always in an open state.

According to the present invention, multiple pressure adjustment means are installed, each of which has a capacity capable of independently maintaining the air pressure in the second chamber at a set value, and all of them are constantly operating. Therefore, even if a malfunction occurs in any of the pressure adjustment means, the remaining pressure adjustment means can stably maintain the air pressure in the second chamber at the set value.

As a result, muddy water can move smoothly between the first and second chambers, and the second chamber can provide good responsiveness to fluctuations in muddy water pressure in the first chamber.

1 is a schematic diagram showing the inside of a muddy water shield machine according to one embodiment of the present invention, viewed from the side. FIG. FIG. 2 is an explanatory diagram showing the flow of mud water when the shield machine of FIG. 1 is excavating natural ground. FIG. 2 is an explanatory diagram showing the flow of mud water when the shield machine of FIG. 1 stops excavating natural ground.

Below, an embodiment of the present invention will be described in detail with reference to the drawings. In the drawings for explaining the embodiment, the same components are generally designated by the same reference numerals, and repeated explanations will be omitted.

Figure 1 is a conceptual diagram showing the configuration of a slurry shield tunneling machine, which is one embodiment of the present invention, from the side.

In FIG. 1, the mud shield machine (hereinafter, simply referred to as the "shield machine") 1 of this embodiment excavates the ground by pressing the cutter head 2 against the face (excavation surface) F and rotating it. The mud 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 supply pipe 5, and the mud pressure in the cutter chamber 4 is set to a pressure that matches the earth pressure and groundwater pressure at the face F to stabilize the face F, and the mud stored in the cutter chamber 4 is discharged to the outside of the tunnel by the mud discharge pipe 6 together with the excavated soil taken into the cutter chamber 4 to form a tunnel in the ground. The mud sent to the cutter chamber 4 is stored in a mud plant 7 installed outside the mine and is pumped out by a mud supply pump 8. In addition, bentonite, polymer additives, etc. are mixed into the mud in the mud, which forms a film (mud film) at the face F to prevent the mud from flowing into the gaps in the ground ahead.

The mud water type shield tunneling machine 1 is suitable for construction in ground with high water pressure because the penetration of the mud water has a stabilizing effect on the face F. On the other hand, in highly permeable ground or ground with large boulders, there is a risk of lost mud flow, which increases the amount of mud water flowing in from the ground. Therefore, the mud content and polymer additives in the mud water are increased, and the amount of mud water supplied is increased to reinforce the mud film and stabilize the pressure in the cutter chamber.

The cutter head 2 that constitutes the shield tunneling machine 1 is an excavation member that is circular in front view and excavates the face F of the ground, and is installed on the front side of the skin plate 3 in a state where it can rotate freely in both forward and reverse directions along the circumferential direction of the skin plate 3.

In this embodiment, a face plate type cutter head 2 is used, and a number of bits and scraper teeth (neither shown) are attached to the front surface (the surface facing the face F) for crushing boulders and excavating the natural ground. In addition, the cutter head 2 is formed with a soil intake port (not shown) for taking in soil and sand excavated by the rotation of the cutter head 2 into the cutter chamber 4.

The skin plate 3 located behind the cutter head 2 is formed, for example, from a steel plate with a cylindrical radial cross section. A bulkhead 9 is installed in a position set back inward from the front surface of the skin plate 3 (where the cutter head 2 is installed), dividing the inside of the skin plate 3 into a face side and an inboard side. A cutter chamber 4, which is the first chamber, is formed on the face side of the skin plate 3, i.e., between the cutter head 2 and the bulkhead 9.

The cutter chamber 4 is a space (chamber) that takes in the soil and sand excavated by the rotation of the cutter head 2 and mixes it with the mud water supplied through the mud transport pipe 5. As mentioned above, the mud water pressure in the cutter chamber 4 is adjusted to a pressure that matches the earth pressure and groundwater pressure at the face F, thereby pressing down and stabilizing the face F.

Inside the skin plate 3, there are a cutter drive unit that rotates the cutter head 2 in forward and reverse directions, a bending jack that connects the skin plate 3 (front and rear plates) that are divided into front and rear parts and can be bent, and corrects the direction of advancement of the shield tunneling machine 1, a shield jack that uses reaction force from the segments laid behind the skin plate 3 to move the shield tunneling machine 1 forward, and an erector that assembles multiple pieces into a ring near the rear end of the skin plate 3 to build segments around the inner circumference of the tunnel.

In addition, the aforementioned mud transport pipe 5 and mud discharge pipe 6 are installed so as to extend from inside the skin plate 3 to the outside of the mine.

The mud pipe 5 is a pipe that supplies mud water into the cutter chamber 4, and is made of, for example, steel. The tip of the mud pipe 5 (mud discharge port) penetrates the upper inside front part of the partition wall 9 and reaches the cutter chamber 4. As a result, the mud water pressurized through the mud pipe 5 is supplied from the upper inside front part of the shield machine 1 into the cutter chamber 4. This mud pipe 5 extends toward the tunnel mouth and is connected to the mud water plant 7 outside the tunnel via the aforementioned mud water pump 8 placed midway. The mud water plant 7 is connected to a mud water treatment device (not shown) outside the tunnel.

The mud discharge pipe 6 is a pipe that discharges the muddy water (a mixture of excavated soil and muddy water) in the cutter chamber 4 to the outside of the tunnel, and is made of, for example, steel. The tip of the mud discharge pipe 6 (mud intake port) penetrates the lower front inside of the partition wall 9 and reaches the cutter chamber 4. As a result, the muddy water in the cutter chamber 4 is discharged from the lower front inside of the shield tunneling machine 1. The mud discharge pipe 6 extends toward the tunnel mouth and is connected to a muddy water treatment device outside the tunnel via a muddy water pump 10 placed along the way.

That is, the muddy water discharged from the cutter chamber 4 is sent through the muddy water discharge pipe 6 to a muddy water treatment device outside the tunnel, where it is separated into soil and muddy water and its specific gravity, viscosity, etc. are adjusted, and then it is sent to the muddy water plant 7 and sent back to the cutter chamber 4 through the muddy water delivery pipe 5.

As shown in FIG. 1, the shield tunneling machine 1 of this embodiment has an auxiliary chamber (second chamber) 11 installed behind the cutter chamber 4. The auxiliary chamber 11 is connected to the cutter chamber 4 by a pressure adjustment pipe 13, and is a small pressure vessel through which mud water flows between the auxiliary chamber 11 and the cutter chamber 4.

Because the auxiliary chamber 11 is connected to the cutter chamber 4 by the pressure adjustment pipe 13, the lower layer in the chamber is a muddy water layer (reserved muddy water). As shown in FIG. 1, in this embodiment, the connection position of the pressure adjustment 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. This is because the role of the auxiliary chamber 11 is to adjust the pressure, and the concentration of the muddy water does not affect its function, so it is desirable for the concentration of the muddy water in the chamber to be low. In other words, the muddy water in the cutter chamber 4 is high near the bottom and becomes low as the height increases, so if the pressure adjustment pipe 13 is connected near the bottom of the cutter chamber 4, the high concentration muddy water in the cutter chamber 4, that is, the muddy water containing a lot of sediment, will easily flow into the auxiliary chamber 11, and sediment will easily accumulate at the bottom of the auxiliary chamber 11, which is undesirable because the connection with the pressure adjustment pipe 13 will be filled up. For this reason, the connection position of the pressure adjustment pipe 13 on the cutter chamber 4 side is as described above, in order to prevent the intake of sediment by allowing relatively low-concentration muddy water to flow in.

As also shown in Figure 1, the connection position of the mud pipe 5 on the cutter chamber 4 side is higher than the connection position of the pressure adjustment pipe 9 at the bulkhead 9, closer to the upper end. This is because the mud pressure in the cutter chamber 4 decreases the further up it goes, so by connecting the mud pipe 5 to a position where the mud pressure is low, mud can flow smoothly into the cutter chamber 4.

As shown in FIG. 1, in this embodiment, the pressure adjustment pipe 13 is connected to a position including the bottom of the auxiliary chamber 11. This is to ensure that the pressure adjustment pipe 13 faces the muddy water layer in the auxiliary chamber 11. However, this connection form 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 an air pressure pipe 15. Therefore, the upper part of the auxiliary chamber 11 is a compressed air layer. In this embodiment, the air pressure pipe 15 does not have a pressure adjustment function, and the compressed air stored in the receiver tank 14 is constantly supplied to the auxiliary chamber 11. Furthermore, a pressure adjustment valve (pressure adjustment means) 17 is installed on the upper surface of the auxiliary chamber 11, which maintains the air pressure in the chamber at a set value by adjusting the valve opening according to the pressure.

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

The pressure adjustment valve 17 may be one whose opening changes automatically according to air pressure, or one whose opening is controlled by a servo motor or the like. However, from the standpoint of ease of control, it is preferable that the opening of the pressure adjustment valve 17 be about 10%.

When the pressure inside the receiver tank 14 falls below 0.31 MPa, the compressor 16 operates, and when it exceeds 0.35 MPa, it stops. Compressed air is constantly being supplied from the receiver tank 16 to the auxiliary chamber 11. Furthermore, a stable air pressure can be maintained by constantly discharging air from the pressure control valve 17 of the auxiliary chamber 11.

In this embodiment, the capacity of the auxiliary chamber 11 is 5.0 ^m3 , while the capacity of the receiver tank 14 is 2.26 ^m3 . The compressor 16 is used at maximum output, and a large output is preferable.

In this way, the internal pressure of the auxiliary chamber 11 is kept constant, so even if mud flows in from the pressure adjustment pipe 13 in response to fluctuations in the pressure in the cutter chamber 4 and the water level of the muddy water layer changes, the compressed air in the upper layer acts as an air pressure damper to absorb the fluctuations in face pressure, so the pressure on the face F of the cutter head 2 can be kept constant.

However, the pressure, capacity, and other values shown above are merely examples, and the present invention is of course not limited to these values.

The receiver tank 14 is always connected to the compressor 16, but when the pressure of the compressed air in the receiver tank 14 exceeds a certain value, the compressor 16 stops, preventing the pressure in the receiver tank 14 from rising above a certain level.

In addition, the compressed air supply means consisting of the receiver tank 14 and the compressor 16 is mounted on a trailing carriage that moves forward following the forward movement of the shield tunneling machine 1.

A pressure gauge P is installed in the center of the partition wall 9 in the vertical direction to detect the mud water pressure in the cutter chamber 4.

The pressure gauge P is used to control the mud pressure in the cutter chamber 4 to a pressure that counteracts the pressure in front of the face. Like water pressure, the mud pressure in the face F and cutter chamber 4 is lower at the top and higher downwards. The pressure in the cutter chamber 4 is controlled by estimating the value detected by the pressure gauge P, which is the value at the center position of the height of the bulkhead 9, as the overall average value. Therefore, the center of the height of the bulkhead 9 is the mud pressure control height. However, the mud pressure control height does not have to be the center of the height of the bulkhead 9; for example, the height indicating the average value obtained from the actual mud pressure distribution in the cutter chamber 4 may be used as the mud pressure control height.

The pressure gauge P does not have to be located at a single point in the center of the height of the partition 9. That is, in the case of a shield tunneling machine 1 with a relatively small diameter, one can be installed on each side of the center of the height of the partition 9. Also, in the case of a shield tunneling machine 1 with a relatively large diameter, the pressure gauge can be installed on the left and right of the center of the height of the partition 9, and above and below the center, and the value at the center of the height can be estimated and managed by assuming that the mud water pressure is a trapezoidal distribution that is higher as it goes downwards.

In this embodiment, two (or more) pneumatic pipes 15 that supply compressed air from the receiver tank 14 to the auxiliary chamber 11 are provided in parallel. The two pneumatic pipes 15 are always open, and compressed air always flows from the receiver tank 14 to the auxiliary chamber 11. Each pneumatic pipe 15 has a capacity that allows compressed air of a predetermined pressure to flow from the receiver tank 14 to the auxiliary chamber 11 on its own. Therefore, each pneumatic pipe 15 always functions at half or less of its original capacity.

Two (or more) pressure regulating valves 17 are installed to keep the pressure of the compressed air in the auxiliary chamber 11 constant. These two pressure regulating valves 17 are constantly operating, working together to discharge the compressed air in the auxiliary chamber 11 and maintain the air pressure in the auxiliary chamber 11 at a set value. Each of these pressure regulating valves 17 has a capacity that allows it to independently maintain the air pressure in the auxiliary chamber 11 at a set value. Therefore, each pressure regulating valve 17 constantly functions at half or less of its original capacity.

With these two pneumatic pipes 15 or two pressure regulating valves 17, if one of the pneumatic pipes 15 or pressure regulating valves 17 malfunctions, the other automatically responds (i.e., the other pneumatic pipe 15 supplies the required amount of compressed air, or the other pressure regulating valve 17 discharges the required amount of compressed air), making it possible to repair the tunnel without stopping excavation. Also, in the unlikely event that the amount of air flow exceeds the amount expected at the time of design, it is possible to respond to up to twice or more. Furthermore, since the pneumatic pipes 15 and pressure regulating valves 17 are constantly operating, their capacity only changes depending on malfunctions or unexpected amounts of air flow, so accidents can be responded to more quickly than if they were stopped as a backup and operated only when necessary. As a result, it becomes possible to stably maintain the air pressure in the auxiliary chamber 11 at the set value.

As shown in FIG. 1, each pressure regulating valve 17 is provided with an opening sensor (detection means) that detects the degree of opening (state) of the pressure regulating valve 17. This allows an operator to quickly find and repair a malfunctioning pressure regulating valve 17 simply by checking whether there is a difference in the numerical values of the opening sensor of each pressure regulating valve 17 and the amount of change in opening when the pressure in the auxiliary chamber 11 changes. A flow meter (detection means) that detects the flow rate of compressed air flowing through the pipe in which the pressure regulating valve 17 is installed may be provided so that the occurrence of a malfunction can be detected by the flow meter.

Furthermore, a supply pipe 12 branching off from the mud transport pipe 5 is connected to the auxiliary chamber 11, so that the mud water flowing through the mud transport pipe 5 can also flow into the auxiliary chamber 11. Also, a discharge pipe 18 is connected to the mud discharge pipe 6 so as to extend from the bottom surface of the auxiliary chamber 11. The mud transport pipe 5 and the mud discharge pipe 6 are connected directly (i.e., without passing through the cutter chamber 4) by a bypass pipe 19.

The discharge pipe 18 extending from the auxiliary chamber 11 is connected to the sludge discharge pipe 6 because the pressure of the running water in the sludge discharge pipe 6 can suck up the sand accumulated in the auxiliary chamber 11 through the discharge pipe 18. In order to efficiently discharge the soil and sand in the auxiliary chamber 11, it is preferable that the discharge pipe 18 is connected so as to extend from the bottom surface of the auxiliary chamber 11.

As shown in the figure, the junction connection point Pm between the discharge pipe 18 and the sludge discharge pipe 6 is upstream of the sludge pump 10 described above in the direction of muddy water flow. This is because if the junction connection point Pm is downstream of the sludge pump 10 in the direction of muddy water flow, when the pressure in the sludge discharge pipe 6 is high, the suction force in the auxiliary chamber 11 will be too strong and the water level in the auxiliary chamber 11 will drop too much. However, if the amount of sediment in the auxiliary chamber 11 is large, the junction connection point Pm may be downstream of the sludge pump 10 in the direction of muddy water flow, and further, the sludge discharge pump 10 may be connected upstream and downstream of the junction connection point Pm to selectively operate depending on the situation.

In this embodiment, a sludge tank 20 is connected to the bottom of the auxiliary chamber 11 via a drain pipe 21. If the muddy water in the auxiliary chamber 11 contains a large amount of soil and sand, a seventh valve V7 provided on the drain pipe 21 is opened to discharge the soil and sand from the auxiliary chamber 11 into the sludge tank 20. Therefore, even if the muddy water in the auxiliary chamber 11 is discharged from the drain pipe 21, the muddy water will not contaminate the inside of the tunnel. The muddy water in the sludge tank 20 is discharged outside the machine by negative pressure suction using a vacuum cleaner (not shown) via the suction pipe 22.

In this way, in the shield machine 1 of this embodiment, two routes are provided for discharging mud water from the auxiliary chamber 11: a first route from the discharge pipe 18 to the mud discharge pipe 6, and a second route from the drain pipe 21 to the mud discharge tank 20. This is intended for a situation in which it becomes necessary to discharge mud water from the auxiliary chamber 11, but discharging via the first route is not possible due to high water pressure in the mud discharge pipe 6. However, even if it is possible to discharge mud water via the first route, it may be discharged via the second route, or the first and second routes may be used together. Furthermore, only one of the first and second routes may be provided.

A water level gauge (not shown) is also installed in the auxiliary chamber 11. This water level gauge is intended to detect the flow direction of the muddy water passing between the auxiliary chamber 11 and the cutter chamber 4 (the direction in which the muddy water is flowing) by measuring the increase or decrease in the water level in the auxiliary chamber 11. However, instead of the water level gauge, a flow direction gauge may be installed in the pressure adjustment pipe 13 to detect the flow direction of the muddy water passing between the auxiliary chamber 11 and the cutter chamber 4.

As shown in the figure, a first valve V1 is attached to the cutter chamber 4 side of the branch connection point Pb1 with the bypass pipe 19 in the sludge feed pipe 5, and a second valve V2 is attached to the cutter chamber 4 side of the branch connection point Pb2 with the bypass pipe 19 in the sludge discharge pipe 6. In addition, a third valve V3 is attached to the bypass pipe 19, a fourth valve V4 is attached to the supply pipe 12, a fifth valve V5 is attached to the discharge pipe 18, and a sixth valve V6 is attached to the pressure adjustment pipe 13. Furthermore, as described above, a seventh valve V7 is attached to the drain pipe 21 connecting the auxiliary chamber 11 and the sludge discharge tank 20.

Each of these valves V1 to V7 is used to open and close the respective pipelines. In this embodiment, data showing the working state of the shield tunneling machine 1 (ground excavation in progress/ground excavation stopped), measurements taken by the pressure gauge P and concentration meter of the muddy water in the cutter chamber 4, measurements taken by the water level gauge and water meter (described later) and pressure gauge P in the auxiliary chamber 11, etc. are collected, and based on this, the valves are automatically opened and closed by actuators such as motors controlled by a control unit (not shown).

However, it is also possible to have an operator open and close valves V1 to V7 via actuators without providing a control unit.

A check valve (eighth valve) V8 is installed on the sludge discharge pipe 6 side of the fifth valve V5 attached to the discharge pipe 18. This is to prevent muddy water from flowing back from the sludge discharge pipe 6 through the discharge pipe 18 into the auxiliary chamber 11 when the water pressure in the sludge discharge pipe 6 is higher than the water pressure in the discharge pipe 18.

The flow of mud in the shield machine 1 having the above configuration will be explained using Figures 2 and 3. In Figures 2 and 3, the pipelines through which mud flows are indicated by thick solid lines, and pipelines through which mud sometimes flows and other times does not flow are indicated by thick dashed lines. Figure 2 shows the cutter chamber circulation mode in which mud flows back through the cutter chamber 4 (i.e., without passing through the bypass piping 19), while Figure 3 shows the bypass circulation mode in which mud flows back through the bypass piping 19 (i.e., without passing through the cutter chamber 4). Valves V1 to V7, which open and close the pipelines to control the flow of mud, are controlled by the control unit as described above.

In FIG. 2, when excavating the natural ground, the sixth valve V6 is first opened. Next, the first valve V1 and the second valve V2 are opened, and the third valve V3 is closed (cutter chamber return mode). Then, the mud pump 8 supplies the mud stored in the mud plant 7 through the mud pipe 5 into the cutter chamber 4, and the mud pressure in the cutter chamber 4 is adjusted to a pressure that matches the earth pressure and groundwater pressure at the face F to stabilize the face F. At the same time, the mud stored in the cutter chamber 4 is returned to the mud plant 7 outside the tunnel by the mud discharge pipe 6 together with the excavated soil taken into the cutter chamber 4, forming a tunnel in the natural ground.

In addition, in response to fluctuations in the mud water pressure in the cutter chamber 4, mud water flows between the cutter chamber 4 and the auxiliary chamber 11 via the pressure adjustment pipe 13, thereby mitigating pressure fluctuations in the cutter chamber 4.

At this time, the connection position of the pressure adjustment pipe 13 on the cutter chamber 4 side is above the center of the height of the cutter chamber 4 on the partition wall 9, so that relatively low concentration muddy water flows from the cutter chamber 4 to the auxiliary chamber 11, suppressing the intake of sediment.

In this way, with the sixth valve in the open position, the auxiliary chamber 11 is constantly connected to the cutter chamber 4. However, if some unforeseen event 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 mitigate the pressure fluctuations in the cutter chamber 4. Therefore, only in such a case will the sixth valve V6 be closed to disconnect the two.

In this embodiment, the mud concentration in the cutter chamber 4 is adjusted in the following manner when there is lost mud. That is, whether or not there is lost mud is determined from the calculation of the amount of lost mud, and this is done even when the water level in the auxiliary chamber 11 does not fluctuate. Specifically, the lost mud state is determined when the amount of lost mud in a day (= (amount of mud sent + amount of excavated soil) - amount of mud discharged) is 10% or more of the total amount. The mud concentration is managed by specific gravity, with the standard being 1.2, and is increased to 1.25 in the case of lost mud. The specific gravity of the mud is set at a maximum of about 1.3, and the standard is 1.22 when the amount of lost mud is not large.

In addition, if the daily lost mud volume falls to 1% or less of the total volume, it will be determined that the lost mud volume has subsided, and the possibility of returning the mud concentration to 1.2 will be considered. The reason why there is room for not returning the mud concentration to 1.2 here is that changing the mud concentration requires major adjustments, such as changing the vibrating screens and thickener bag filters on the ground, and if there is no problem with drilling with the mud concentration increased, it is preferable to continue as is.

Conversely, the water pressure at the face F may increase, causing groundwater to flow into the cutter chamber 4 and rising the water level. In this embodiment, the tolerance for this is set to plus or minus 3%, and if the water level rises by 3% or more for a full day, the mud pressure in the cutter chamber 4 is gradually increased to balance with the face F. The mud pressure in the cutter chamber 4 is adjusted by the pressure gauge P within the range of the control value (between the active and passive earth pressures of the ground), and the mud pressure is returned to the allowable value when it returns to the allowable value. 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 that branches off from the mud supply pipe 5 to the cutter chamber 4, and further, the discharge pipe 18 is connected to the mud discharge pipe 6 to prevent the amount of mud water inside the auxiliary chamber 11 from becoming too large. In addition, a fourth valve is installed on the supply pipe 12, and a fifth valve is installed on the discharge pipe 18. Therefore, when excavating the natural ground, the amount of mud water in the auxiliary chamber 11 is adjusted according to the measurement value of a water gauge (not shown) that measures the amount of water in the auxiliary chamber 11 by appropriately opening and closing the fourth valve V4 and the fifth valve V5.

As a result, even if mud loss occurs in the cutter chamber 4 and the mud in the auxiliary chamber 11 flows into the cutter chamber 4 through the pressure adjustment pipe 13, the fourth valve V4 opens and the mud in the mud feed pipe 5 is supplied from the supply pipe 12 into the auxiliary chamber 11, so the water level does not become too low and cause excavation to stop, or the water level does not become too low and cause the compressed air in the auxiliary chamber 11 to flow into the cutter chamber 4 through the pressure adjustment pipe 13.

Next, as shown in Figure 3, when excavation of the ground is stopped, such as when assembling the segments, excavation by the cutter head 2 is stopped and the pressure at the face F does not change, so in order to fix the mud pressure in the cutter chamber 4 at the pressure at that time, the first valve V1 and the second valve V2 are closed and the third valve V3 is opened (bypass return mode). As a result, the mud is not supplied to the cutter chamber 4, but flows from the mud supply pipe 5 through the bypass piping 19 into the mud discharge pipe 6, and after the excavated soil is removed outside the tunnel, it is returned by the mud supply pump 8 via the mud plant 7.

As mentioned above, two air pressure pipes 15 are provided in parallel and are always open, and each is capable of flowing compressed air at a predetermined pressure from the receiver tank 14 into the auxiliary chamber 11 on its own. Two pressure regulating valves 17 are also installed and are always in operation, and each is capable of maintaining the air pressure in the auxiliary chamber 11 at a set value on its own.

Therefore, if a malfunction occurs in either the air pressure pipe 15 or the pressure adjustment valve 17 during operation of the above-mentioned shield tunneling machine 1, the other will automatically respond. This makes it possible to stably maintain the air pressure in the auxiliary chamber 11 at the set value.

In addition, if the amount of air flow exceeds what was anticipated during the design process, it is possible to accommodate up to twice the capacity or more. In this way, the capacity only changes in response to malfunctions or unexpected air flow, allowing for a quick response to accidents.

Furthermore, during normal operation of the shield tunneling machine 1, two pneumatic pipes 15 and two pressure regulating valves 17 are in operation, allowing for good responsiveness to pressure fluctuations within the auxiliary chamber 11.

The invention made by the inventor has been specifically described above based on the embodiments, but the embodiments disclosed in this specification are illustrative in all respects and are not limited to the disclosed technology. In other words, the technical scope of the present invention should not be interpreted restrictively based on the explanation in the above embodiments, but should be interpreted solely in accordance with the claims, and includes technologies equivalent to the technologies described in the claims and all modifications that do not deviate from the gist of the claims.

For example, in this embodiment, two pneumatic pipes 15 are provided in parallel and two pressure adjustment valves 17 are installed, but there may be more than one of these, and the number is not limited to two.

In addition, two (or more) pressure adjustment valves 17 are sufficient, and only one pneumatic pipe 15 is required. This is because the pneumatic pipe 15 only carries compressed air from the receiver tank 14, so it is less likely to malfunction than the pressure adjustment valve 17.

In addition, a pressure adjustment means such as a pressure adjustment valve may also be provided in the pneumatic pipe 15. In this case, the pressure adjustment means may be provided only in the pneumatic pipe 15, or may be provided in both the pneumatic pipe 15 and the exhaust pipe in which the pressure adjustment valve 17 is installed.

The above explanation has been given of the application of the present invention to a muddy shield tunneling machine, but there are no particular limitations on the shape and structure of the cutter head, etc., which are not related to the present invention.

1 Shield tunneling machine 2 Cutter head 3 Skin plate 4 Cutter chamber (first chamber)
5 Mud pipe 6 Mud discharge pipe 7 Mud plant 8 Mud pump 9 Bulkhead 10 Mud discharge pump 11 Auxiliary chamber (second chamber)
12 Supply pipe 13 Pressure adjustment pipe 14 Receiver tank 15 Air pressure pipe 16 Compressor 17 Pressure adjustment valve 18 Discharge pipe 19 Bypass pipe 20 Sludge tank 21 Drain pipe 22 Suction pipe F Face FM Flow meter P Pressure gauges Pb1, Pb2 Branch connection point Pm Confluence 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 partition;
a mud pipe for feeding mud water into the first chamber;
a mud discharge pipe for discharging the muddy water stored in the first chamber together with the excavated soil taken into the first chamber to the outside;
a second chamber for storing compressed air and muddy water, communicating with the first chamber through a pressure regulating pipe, and allowing muddy water to pass between the second chamber and the first chamber through the pressure regulating pipe to reduce fluctuations in muddy water pressure in the first chamber;
a compressed air supply means for supplying compressed air at a predetermined pressure into the second chamber via an air pressure pipe;
a pressure adjusting means, the pressure adjusting means being installed in the second chamber and constantly operating, each capable of independently maintaining the air pressure in the second chamber at a set value, and discharging compressed air in the second chamber in cooperation with the pressure adjusting means to maintain the air pressure in the second chamber at the set value;
A detection means is provided in each pipe in which the pressure regulating means is provided, and detects the state of the pressure regulating means or the flow rate of compressed air flowing through the pipe;
having
The detection results from the respective detection means are compared to find out which of the pressure adjusting means has a malfunction.
A slurry shield tunneling machine characterized by: the pneumatic piping is a plurality of pipings each having a capacity for flowing compressed air at a predetermined pressure from the compressed air supply means into the second chamber, the piping being provided in parallel with each other and the piping being always in an open state;
2. A slurry shield tunneling machine according to claim 1.

Images