Screw conveyor and shield machine with screw conveyor installed

Abstract

To automatically close a gate installed behind a screw impeller vane of a shield machine in the event of a power outage.SOLUTION: A screw conveyor has a cylinder jack 22 for opening and closing a gate 21 installed behind a screw impeller vane 10cb of a screw conveyor 10 installed in a mud pressure shield machine and a hydraulic circuit R for extending and retracting the cylinder jack 22. The hydraulic circuit R comprises a first path R1 that extends and retracts the cylinder jack 22 using hydraulic fluid from a hydraulic pump 31, a second path R2 that retracts the cylinder jack 22 using hydraulic fluid from an accumulator 33, a first solenoid valve 35 that conducts excitation to open the first path R1, allowing the cylinder jack 22 to open and close the gate 21 during energization, and conducts demagnetization to close the first path R1 during a power outage, and second solenoid valves 36a, 36b that conduct excitation to close the second path R2 during energization, conduct demagnetization to open the second path R2 during a power outage, and retract the cylinder jack 22 to close the gate 21.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a technology relating to a screw conveyor and a shield tunneling machine equipped with the screw conveyor. [Background technology]

[0002] A shield tunneling machine is a machine that forms an excavation hole in the ground by pressing a cutter head attached to the front of the machine body against the face of the ground and moving forward while rotating.

[0003] Shield machines are divided into mud pressure shield machines and slurry shield machines. The former are designed to stabilize the tunnel face by injecting a slurry containing water-added bentonite or polymer flocculants into a chamber to turn the excavated soil into a slurry (fluidized) and applying a predetermined pressure. More specifically, the excavated soil fills the space between the tunnel face and the partition wall, and then injects and mixes it with a slurry to create a highly fluid and water-tight mud (a mixture of gravel and slurry). This slurry pressure stabilizes the tunnel face as the machine excavates. The soil mixed with the slurry in the chamber is then taken up by a screw conveyor and discharged from the rear of the machine. The latter are designed to stabilize the tunnel face by applying a predetermined pressure to the slurry in the chamber and transport the excavated soil by circulating the slurry.

[0004] In some earth pressure shield tunneling machines, a gate is installed behind the screw blades in the cylindrical conveyor casing that makes up the screw conveyor, and the gate's opening (i.e., the amount of earth transported by the screw conveyor) is adjusted to stabilize the face by adjusting the amount of earth taken into the screw conveyor from the chamber and controlling the earth pressure within the chamber. Specifically, when there is a risk that the earth pressure within the chamber will be lower than the earth-water pressure at the face due to high groundwater pressure in the excavated ground or other reasons, and the face will become unstable, the gate is used to reduce the radial opening area of ​​the screw conveyor or to close the pipeline, thereby restricting the amount of earth discharged, and increasing the earth pressure within the chamber to counteract the earth-water pressure at the face. Conversely, when the earth pressure within the chamber is higher than the earth-water pressure at the face, the gate is fully opened or the opening area is increased depending on the pressure difference to discharge earth.

[0005] Regarding a shield tunneling machine in which gates are installed on the screw conveyor, the technology described in Patent Document 1 is known, for example. The technology described in Patent Document 1 is equipped with two water-stopping gates, and makes it possible to change the soil discharge path by selectively opening and closing the gates depending on the condition of the excavation face. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-097189 Summary of the Invention [Problem to be solved by the invention]

[0007] In the case of a power outage during construction, with an earth pressure shield machine, it is necessary to quickly close the gate, shut off the pipeline, and stop the discharge of soil in order to prevent a drop in the earth pressure in the chamber and stabilize the face. Therefore, in preparation for an emergency such as a power outage, the gate is equipped with a manual accumulator and hydraulic pump in addition to the hydraulic pump that operates the opening and closing jack that opens and closes the gate during construction. Alternatively, an auxiliary gate is installed behind the gate to manually shut off the pipeline.

[0008] With this type of manual pipeline shutoff mechanism, when a power outage occurs, workers must move around the dimly lit interior of the shield tunneling machine to operate manual accumulators, hydraulic pumps, or auxiliary gates. This requires time to operate, and during that time there is a concern that water may leak from the ground or soil may erupt from the screw conveyor.

[0009] The present invention has been made in light of the above-mentioned technical background, and aims to provide a technology that can automatically close a gate installed behind a screw blade in a screw conveyor of a shield tunneling machine in the closed position in the event of a power outage. [Means for solving the problem]

[0010] In order to solve the above problems, the screw conveyor of the present invention as set forth in claim 1 is a screw conveyor installed in a shield machine that excavates natural ground to construct a tunnel while stabilizing the tunnel face by injecting a mud-adding material into a chamber to turn the excavated earth introduced into the chamber into mud and applying a predetermined pressure, and comprises a cylindrical conveyor casing installed obliquely upward from a soil intake end where the earth in the chamber is taken in to a soil discharge end where the taken-in earth is discharged, screw blades installed along the axial direction within the conveyor casing to take in earth from the soil intake end into the conveyor casing and transport it from the soil discharge end to the outside of the machine, and a screw blade installed behind the screw blade in an openable and closable manner, and the conveyor The hydraulic circuit includes a gate that opens and closes the transport path for soil and sand inside a casing, a cylinder jack that opens and closes the gate by extending and retracting, and a hydraulic circuit that extends and retracts the cylinder jack, wherein the hydraulic circuit includes a first path that extends and retracts the cylinder jack with hydraulic oil from a hydraulic pump, a second path that retracts the cylinder jack with hydraulic oil from an accumulator, a first solenoid valve that is energized to open the first path to open and close the gate with the cylinder jack when power is applied, and is demagnetized to close the first path when a power outage occurs, and a second solenoid valve that is energized to close the second path when power is applied, and is demagnetized to open the second path when a power outage occurs, thereby retracting the cylinder jack and bringing the gate to a closed position.

[0011] The screw conveyor of the present invention described in claim 2 is the invention described in claim 1, characterized in that the first solenoid valve is a solenoid valve that switches the valve element by selectively energizing two solenoids to switch the supply path of hydraulic oil to the cylinder jack and closes the first path with a spring force when demagnetized, and the second solenoid valve is a solenoid valve that closes the second path when energized and opens the second path with a spring force when demagnetized.

[0012] The shield tunneling machine of the present invention as set forth in claim 3 is characterized in that the screw conveyor as set forth in claim 1 or 2 is installed. [Effects of the Invention]

[0013] In the present invention, if a power outage occurs during construction, the first solenoid valve closes the first path when demagnetized, and the second solenoid valve opens the second path when demagnetized, causing the cylinder jack rod to contract and automatically closing the gate to the closed position. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a configuration diagram showing the inside of an earth pressure shield machine according to an embodiment of the present invention as seen from the side. [Figure 2] FIG. 2 is a front view of the cutter head of the earth pressure shield machine of FIG. 1. [Figure 3] 2 is an explanatory diagram of a gate provided on a screw conveyor of the mud pressure shield machine of FIG. 1, viewed from the direction of earth and sand transport of the conveyor casing. FIG. [Figure 4] FIG. 5 is a side view of the gate of FIG. 4. [Figure 5] 1 is a diagram showing a hydraulic circuit for extending and retracting a cylinder jack that opens and closes a gate provided in an earth pressure shield machine of this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, 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 description thereof will be omitted.

[0016] FIG. 1 is a configuration diagram showing the inside of an earth pressure shield machine of this embodiment as seen from the side, and FIG. 2 is a front view of a cutter head of the earth pressure shield machine of FIG.

[0017] The mud pressure shield tunneling machine (shield tunneling machine) 1 of this embodiment is an equipment that generates mud pressure by excavating while filling the chamber between the cutter head 2 and the equipment body 3 with mud that is impermeable and has plastic fluidity (the ability to deform and move freely) by injecting and mixing mud-adding material into the soil and sand excavated by the cutter head 2, and then constructs an excavation tunnel with this mud pressure counteracting the earth pressure at the face.

[0018] The operation of the mud pressure shield machine 1 is controlled by an operator in a cab in a trailing carriage (not shown) located behind it.

[0019] The cutter head 2 is a component that excavates the natural ground face and is installed on the front surface of the equipment body 3 in a state where it can rotate freely around the circumferential direction of the equipment body 3. For example, a spoke-type cutter head composed of a plurality of spokes extending radially is adopted for this cutter head 2. That is, as shown in FIG. 2 , the cutter head 2 includes a hub portion 2a located at the center of rotation, six spoke portions 2b extending radially from the hub portion 2a toward the outer periphery, an intermediate ring portion 2c connecting the middle portions of the spoke portions 2b in the extension direction, an outer peripheral ring portion 2d connecting the tip ends of the spoke portions 2b, and through holes 2e formed between the spoke portions 2b for introducing excavated soil into the chamber 6.

[0020] A center bit (bit) 4a is attached to a hub portion 2a of the cutter head 2. Note that other excavation members such as a cone head type roller bit may also be attached to the hub portion 2a.

[0021] As shown in the figure, each spoke portion 2b of the cutter head 2 in this embodiment is formed so that its widthwise dimension (the direction of rotation of the cutter head 2) becomes wider from the center portion in the extension direction of the spoke portion 2b (here, slightly closer to the hub portion 2a than the attachment position of the intermediate ring portion 2c) to the inside (hereinafter referred to as the "inner peripheral side") as it moves away from the hub portion 2a, and so that the widthwise dimension becomes uniform from the center portion in the extension direction of the spoke portion 2b to the outside (hereinafter referred to as the "outer peripheral side"). However, the shape of the spoke portion 2b is not limited to this, and the spoke portion 2b may be formed to have the same width over the entire length of the spoke portion 2b, or may be formed so that it becomes wider over the entire length of the spoke portion 2b as it moves away from the hub portion 2a.

[0022] Each spoke 2b is fitted with a leading bit 4b that crushes boulders and excavates the natural ground, scraper teeth 4s that excavate the natural ground and collect the excavated soil into chamber 6 (Fig. 1), and wear-resistant steel plates 4t that protect both outer edges and surfaces on the inner periphery of the spoke 2b in the width direction. In addition to the leading bit 4b, other excavation components such as roller bits may also be fitted to the front of the spoke 2b.

[0023] The hub portion 2a and the spoke portions 2b are provided with a mud addition material inlet 5a. The mud addition material inlet 5a is a component for injecting mud addition material toward the face at the front of the cutter head 2.

[0024] A number of outer bits (bits) 4c are mounted in a row on the front face of the outer ring section 2d on the face side. Also, for example, two copy bits 4d are provided at opposite positions on the outer periphery of the outer ring section 2d. These copy bits 4d are used for over-excavation during sharp curve construction and for controlling the attitude of the earth pressure shield machine 1.

[0025] 1, the equipment main body 3 comprises a forward body plate 3a in the girder section and an aft body plate 3b in the tail section behind it. The forward body plate 3a and the aft body plate 3b are formed, for example, from cylindrical steel plates, and are members that form the outer shape of the equipment main body 3 and also form a hollow space inside the equipment main body 3. The forward body plate 3a and the aft body plate 3b are engaged with each other by inserting a spherical bearing portion at the tip of the aft body plate 3b into the forward body plate 3a at the aft end side of the forward body plate 3a while contacting the inner circumferential surface of the forward body plate 3a.

[0026] On the front side of the front body plate 3a, at a position set back from the front side into the main body 3, there is provided a partition wall 7 that divides the hollow space within the main body 3 into a face side and an inboard side. A chamber 6 is provided on the face side of this partition wall 7 (i.e., between the cutter head 2 and the partition wall 7), and on the inboard side of the partition wall 7 there are provided a mud-adding material injector 5b, a cutter driver 8, a center bending jack 9a, a shield jack 9b, a screw conveyor 10, and an earth pressure detector (not shown).

[0027] The mud adding agent injector 5b is a device that injects mud adding agent around the outside of the device main body 3 and into the chamber 6, and is located near the outer periphery of the partition wall 7 with the inlet of the mud adding agent injector 5b exposed to the outside of the device main body 3. The mud adding agent injected from the mud adding agent injector 5b is a mud adding agent such as a bentonite-based mud adding agent. Note that the mud adding agent injected from the mud adding agent injector 5b may be an aerated agent instead of a bentonite-based mud adding agent, or both a bentonite-based mud adding agent and an aerated agent may be used.

[0028] The chamber 6 is a space into which the soil and sand excavated by the cutter head 2 is taken. Inside this chamber 6, a mixing blade 15, such as a cylindrical blade, protruding into the chamber 6 is provided on the front side of the partition wall 7, while a mixing blade 16, such as a cylindrical blade, protruding into the chamber 6 is provided on the back side of the cutter head 2. These mixing blades 15, 16 are offset from each other in the radial direction of the cutter head 2, and when the cutter head 2 rotates, they have the role of stirring and mixing the soil and sand that has entered the chamber 6 with the mud-adding material that has been injected into the chamber 6.

[0029] The cutter driver 8 is a drive source that rotates the cutter head 2. Here, an intermediate support drive system is exemplified as the cutter drive system, and as shown in FIG. 1, multiple cutter drivers 8 are arranged side by side along the circumferential direction of the cutter head 2 at positions approximately in the center between the center of the front surface of the cutter head 2 and the outer periphery.

[0030] The articulating jacks 9a are devices that connect the front and rear plates 3a and 3b and correct the forward movement direction of the earth shield machine 1, and as shown in Figure 1, multiple jacks are arranged side by side along the circumferential direction of the earth shield machine 1, at positions that straddle the boundary between the front and rear plates 3a and 3b within the equipment body 3. By supplying pressure oil to these articulating jacks 9a and propelling the earth shield machine 1 with the front and rear plates 3a and 3b bent in a predetermined direction and angle, it is possible to control the forward movement direction of the earth shield machine 1.

[0031] The shield jack 9b is a device that generates a propulsion force to advance the mud shield machine 1 by receiving a reaction force from the segment SG installed at the rear of the equipment main body 3. As shown in Figure 1, the shield jack 9b is fixed to the rear body plate 3b within the equipment main body 3, and multiple shield jacks are arranged in a row along the circumferential direction of the mud shield machine 1.

[0032] The screw conveyor 10 is a device for discharging the soil and sand taken into the chamber 6 outside the machine, and as shown in Figure 1, it extends continuously diagonally upward from the soil and sand intake end 10a, which penetrates the partition 7 at the bottom of the main body 3 and is located inside the chamber 6, to the soil and sand discharge end 10b, which is located at the rear of the main body 3 and slightly higher than the center of the height of the main body 3.

[0033] An earth discharge pipe is connected to the earth discharge end 10b of the screw conveyor 10, and the earth transported to the earth discharge end 10b of the screw conveyor 10 is transported to a cart or the like through the earth discharge pipe.

[0034] The earth pressure detection unit is a sensor that converts the pressure of the mud inside the chamber 6 into an electrical signal via a strain gauge, and is installed with its earth pressure detection surface facing the inside of the chamber 6. The mud pressure shield machine 1 is designed to proceed with the excavation process while maintaining the stability of the face by managing the mud pressure inside the chamber 6 detected by the earth pressure detection unit so that it remains within a predetermined value range.

[0035] In the mud pressure shield machine 1, backfill material is injected into the gaps that form between the segments SG and the excavation wall as the machine advances. Injecting the backfill material prevents ground subsidence and stabilizes the segments SG by integrating the segments SG with the ground, thereby preventing water leakage from the segment joints. Methods for injecting backfill material include an immediate injection method, in which backfill material is injected using backfill material injection ports (not shown) formed in the segments SG, and a simultaneous injection method, in which backfill material is injected in line with excavation through a backfill material injection channel provided at the rear end of the rear body plate 3b. In this embodiment, the immediate injection method is used, but the simultaneous injection method may also be used.

[0036] The screw conveyor 10 described above includes a cylindrical conveyor casing 10ca, which is installed diagonally upward from the sediment intake end 10a where sediment is taken in from the chamber 6 to the sediment discharge end 10b where the sediment is discharged, and a screw blade 10cb installed axially within the conveyor casing 10ca. The screw blade 10cb is used to take the sediment from the chamber 6 into the conveyor casing 10ca and transport it outside the machine. For example, a spiral ribbon screw without a rotating shaft is used. While screw conveyors with a rotating shaft are prone to blockage by boulders, ribbon screws can transport boulders with a maximum diameter greater than the radius of the conveying path, allowing them to transport boulders of a size that cannot be transported by screw conveyors with a rotating shaft. As a result, the mud pressure shield machine 1 of this embodiment is configured to take boulders of a size that can be discharged by the screw conveyor 10 into the chamber 6 without crushing them.

[0037] The screw blade 10cb may be an axial spiral screw blade in which a spiral blade is formed around a rotation axis, instead of an axial spiral ribbon screw as in this embodiment.

[0038] A gate 21 is installed behind the screw blade 10cb to open and close the transport path of soil and sand in the conveyor casing 10ca by the screw blade 10cb. In addition, a hydraulic cylinder jack 22 is attached to the gate 21 to open and close the gate 21 by extending and retracting.

[0039] In Figures 3 and 4, gate 21 is installed at a position where the radial cross section of conveyor casing 10ca is rectangular, making it possible to adjust the opening degree (i.e., adjust the cross-sectional area of ​​the soil transport path of conveyor casing 10ca).

[0040] Specifically, the gate 21 comprises a gate frame 21a, which is a rectangular frame body having a predetermined thickness, a gate body 21b fitted into the gate frame 21a and movable in the vertical direction to adjust the opening degree, and a gate retaining bar 21c screwed to the upper end of the gate body 21b along the width direction of the gate body 21b.

[0041] The gate body 21b is formed in a rectangular shape that is slightly larger than the internal cross-sectional shape of the conveyor casing 10ca, has a predetermined thickness, and is installed within the gate frame 21a so that it can move up and down in a direction perpendicular to the direction of transport of the soil and sand. As shown in the figure, when the gate body 21b moves to the bottom end, the soil and sand transport path is closed, and when it moves to the top end, the soil and sand transport path is fully opened.

[0042] A pair of cylinder jacks 22 each having a rod 22a for vertically moving the gate 21 are installed on both sides of the gate frame 21a. Both ends of the gate holding bar 21c are rotatably attached to the tip of the rod 22a of the cylinder jack 22.

[0043] The cylinder jack 22 is a double-acting hydraulic jack whose rod 22a can be freely adjusted in extension and retraction. Therefore, when the rod 22a of the cylinder jack 22 extends or retracts, the gate body 21b moves up or down accordingly, and the vertical position of the gate body 21b is determined by the extension or retraction of the rod 22a, thereby adjusting the opening degree of the conveyor casing 10ca.

[0044] Next, the hydraulic circuit R that extends and retracts the cylinder jack 22 that opens and closes the gate 21 will be described with reference to FIG.

[0045] As shown in the figure, the hydraulic circuit R has a first path R1 that extends and retracts (extends and contracts) the cylinder jack 22 using hydraulic oil sent from an oil tank 32a (32) by a hydraulic pump 31 driven by an electric motor 30, and a second path R2 that retracts the cylinder jack 22 using hydraulic oil from an accumulator 33.

[0046] The first path R1 has two systems connected to a port on the extension-side cylinder chamber 22-1 side (the cylinder chamber where the rod 22a extends when hydraulic oil is supplied) of the cylinder jack 22 and a port on the retraction-side cylinder chamber 22-2 side (the cylinder chamber where the rod 22a retracts when hydraulic oil is supplied). The end of the first path R1 opposite the cylinder jack 22 side is connected to an oil tank 32a with a filter 34 attached in the hydraulic oil supply system, and is connected to an oil tank 32b (32) in the hydraulic oil return system. While the oil tank 32 is shown separately in FIG. 5, it is the same as the oil tank 32c of the second path R2, which will be described later. However, they may be separate.

[0047] A first solenoid valve 35 is installed on the first path R1, and opens the first path R1 when energized by excitation. This first solenoid valve 35 is a normally closed, four-port, three-position solenoid valve that selectively energizes two solenoids to switch the valve element and switch the supply path of hydraulic oil to the cylinder jack 22, thereby expanding and contracting the rod 22a and opening and closing the gate 21. When demagnetized, the first solenoid valve is placed in a neutral state by a spring force, and the path of hydraulic oil is closed.

[0048] In this first solenoid valve 35, when one solenoid is energized, the valve element is switched, so that the hydraulic oil supply path is connected to the port of the extension-side cylinder chamber 22-1 and the hydraulic oil return path is connected to the port of the contraction-side cylinder chamber 22-2. As a result, hydraulic oil in the oil tank 32a is supplied by the hydraulic pump 31 into the extension-side cylinder chamber 22-1, causing the rod 22a to extend, which in turn moves the gate body 21b upward and opens the gate 21. Furthermore, hydraulic oil pushed out of the contraction-side cylinder chamber 22-2 by the sliding of the rod 22a is collected in the oil tank 32b. When the other solenoid is energized, the valve element is switched, so that the hydraulic oil supply path is connected to the port of the contraction-side cylinder chamber 22-2 and the hydraulic oil return path is connected to the port of the extension-side cylinder chamber 22-1. As a result, hydraulic oil in the oil tank 32a is supplied by the hydraulic pump 31 into the retraction-side cylinder chamber 22-2, causing the rod 22a to retract, which in turn causes the gate body 21b to move downward, closing the gate 21. Additionally, hydraulic oil pushed out from the extension-side cylinder chamber 22-2 by such sliding of the rod 22a is collected in the oil tank 32b.

[0049] As described above, the first solenoid valve 35 provided on the first path R1 is a normally closed, four-port, three-position solenoid valve. Therefore, when demagnetized, the spring force causes the valve to move to a neutral position (a position where no valve element is switched), and the first path R1 is closed.

[0050] The second path R2 also has two systems connected to a port on the extension-side cylinder chamber 22-1 side and a port on the retraction-side cylinder chamber 22-2 side of the cylinder jack 22. The other end of the path connected to the port on the retraction-side cylinder chamber 22-2 side is connected to the accumulator 33, and the other end of the path connected to the port on the extension-side cylinder chamber 22-1 side is connected to the oil tank 32c.

[0051] On the two systems that make up the second path R2, second solenoid valves 36a, 36b are respectively installed. When energized, they close the second path R2 by being energized. These second solenoid valves 36a, 36b are normally open, two-port, two-position solenoid valves. When the solenoid is energized, the valve element moves to a position that blocks the hydraulic oil path, thereby closing the second path R2, and when deenergized, the spring force moves the valve element to a position that opens the hydraulic oil flow path, thereby opening the second path R2.

[0052] Therefore, when the first solenoid valve 35 opens the first path R1 and hydraulic oil from the hydraulic pump 31 extends and retracts the rod 22a, opening and closing the gate 21, the second path R2 is blocked by excitation, and the pressure accumulation function of the accumulator 33 is not applied to the cylinder jack 22. On the other hand, because the solenoid valve 35 is a normally open type, the second path R2 is opened by demagnetization, opening the path from the accumulator 33 to the contraction-side cylinder chamber 22-2 and the path from the extension-side cylinder chamber 22-1 to the oil tank 32c. As a result, hydraulic oil in the accumulator 33 is supplied to the contraction-side cylinder chamber 22-2, contracting the rod 22a. The rod 22a then moves the gate body 21b downward, closing the gate 21. Furthermore, hydraulic oil pushed out of the extension-side cylinder chamber 22-2 by the sliding of the rod 22a is collected in the oil tank 32c.

[0053] The earth pressure shield machine 1 of this embodiment excavates the natural ground and assembles segments SG in the excavation hole. That is, the cutter head 2 is pressed against the face and rotated while advancing the equipment body 3, thereby constructing an excavation shaft in the ground. As the equipment body 3 advances, the annularly assembled segments SG are assembled in the excavation hole from the rear of the rear body plate 3b.

[0054] When excavating the natural ground, mud-adding material is added to the excavated soil taken into the face and chamber 6, and the soil and mud-adding material are stirred and mixed by the rotation of the cutter head 2 and the operation of the mixing blades 16 that follow that rotation, converting the excavated soil into mud with plastic fluidity and impermeability. This mud is then filled into chamber 6 and screw conveyor 10, and the filled mud is pressurized by the driving force of the shield jack 9b to generate mud pressure, which counteracts the earth pressure at the face, maintaining the stability of the face.

[0055] In addition, by injecting backfill material through the backfill material injection port formed in the segment SG to fill the gap that forms between the segment SG and the excavation wall surface, ground subsidence is prevented and the segment SG and the ground are integrated into a single structure, preventing water leakage from the segment joints and stabilizing the segment SG.

[0056] During such excavation, the first solenoid valve 35 is energized and energized to open the first route R1, and the opening of the gate 21 is adjusted by the cylinder jack 22, thereby controlling the mud pressure in the chamber 6 to be within a predetermined range and excavating the natural ground while maintaining the stability of the face. In other words, the natural ground is excavated while the gate 21 adjusts the amount of earth and sand transported by the screw blades 10cb in the conveyor casing 10ca in accordance with the mud pressure in the chamber 6. In addition, the second solenoid valves 36a, 36b are energized and energized to close the second route R2.

[0057] If a power outage occurs during excavation, the solenoid of the first solenoid valve 35 is demagnetized and the spring force places it in a neutral state, closing the first path R1. This stops the opening and closing operation of the gate 21 by the cylinder jack 22. At the same time, the solenoids of the second solenoid valves 36a and 36b are demagnetized and the spring force places the valve bodies in a position that opens the flow path of hydraulic oil, opening the second path R2. This supplies hydraulic oil from the accumulator 33 to the retraction-side cylinder chamber 22-2, retracting the rod 22a and automatically closing the gate 21.

[0058] Thus, in the case of a power outage in the shield machine 1 of this embodiment, the gate 21 installed behind the screw blades 10cb in the screw conveyor 10 is automatically closed by the hydraulic circuit R. This quickly blocks the soil discharge path, preventing a drop in mud pressure in the chamber 6 and stabilizing the tunnel face. Furthermore, because the gate 21 automatically closes, the worker is freed from the task of closing the gate 21 and can concentrate on restoring power.

[0059] Although the invention made by the inventor has been specifically described above based on the embodiments, the embodiments disclosed in this specification are illustrative in all respects and should not be considered to be limited to the disclosed technology. In other words, the technical scope of the present invention should not be interpreted restrictively based on the description of the above embodiments, but should be interpreted solely in accordance with the description of the claims, and includes technologies equivalent to the technologies described in the claims and all modifications within the scope of the claims.

[0060] For example, in this embodiment, a four-port, three-position solenoid valve is used as the first solenoid valve 35, and two-port, two-position solenoid valves are used as the second solenoid valves 36a, 36b, but the first solenoid valve 35 and the second solenoid valves 36a, 36b are not limited to these solenoid valves. In other words, the first solenoid valve may be a solenoid valve that opens the first path R1 when energized to open and close the gate 21 with the cylinder jack 22 and closes the first path R1 when a power outage occurs, and the second solenoid valve may be a solenoid valve that closes the second path R2 when energized and opens the second path R2 when a power outage occurs to retract the cylinder jack 22 and close the gate 21, and the number of ports and the number of positions of the valve body are not particularly limited.

[0061] Furthermore, in this embodiment, a ribbon screw is used for the screw blade 10cb, but the present invention is not limited to this and various modifications are possible. For example, a screw blade with a shaft may be used. [Industrial Applicability]

[0062] The above explanation has been given of the application of the present invention to an intermediate support drive type mud pressure shield machine, but the present invention is not limited to this and can also be applied to various other mud pressure shield machines, such as those with a center shaft drive system or a peripheral support drive system. [Explanation of symbols]

[0063] 1. Mud pressure shield tunneling machine (shield tunneling machine) 2 cutter heads 6 Chambers 10 Screw conveyor 10a Sediment intake end 10b Sediment discharge end 10ca conveyor casing 10ca-1 guide rod 10cb screw blade Gate 21 21a Gate Frame 21b Gate body 21c Gate Retaining Bar 22 Cylinder jack 22-1 Extension side cylinder chamber 22-2 Reducing side cylinder chamber 22a Rod 30 Electric motor 31 Hydraulic pump 32, 32a, 32b, 32c Oil tank 33 Accumulator 34 Filters 35 Solenoid valve 36a, 36b Solenoid valve R Hydraulic circuit R1 Route R2 route

Claims

1. A screw conveyor installed in a shield tunneling machine that excavates the ground while stabilizing the tunnel face by injecting a mud-adding material into a chamber to turn the excavated soil introduced into the chamber into mud and applying a predetermined pressure, a cylindrical conveyor casing installed obliquely upward from a sediment intake end where sediment is taken into the chamber toward a sediment discharge end where the taken-in sediment is discharged; A screw blade is installed along the axial direction inside the conveyor casing, and takes in soil and sand from the soil intake end into the conveyor casing and transports it from the soil discharge end to the outside of the machine; a gate that is installed behind the screw blade in an openable and closable manner and that opens and closes a transport path for soil and sand within the conveyor casing; a cylinder jack that opens and closes the gate by extending and retracting; a hydraulic circuit for extending and retracting the cylinder jack, The hydraulic circuit includes: a first path for extending and retracting the cylinder jack with hydraulic oil from a hydraulic pump; a second path for retracting the cylinder jack with hydraulic oil from an accumulator; a first solenoid valve that is energized to open the first path and open the gate with the cylinder jack when energized, and that is deenergized to close the first path when a power outage occurs; a second solenoid valve that closes the second path by being excited when power is applied, and that opens the second path by being demagnetized when a power outage occurs, thereby contracting the cylinder jack and setting the gate to a closed position, A screw conveyor characterized by:

2. the first solenoid valve is a solenoid valve that switches a valve element by selectively energizing two solenoids to switch a supply path of hydraulic oil to the cylinder jack, and closes the first path by a spring force by demagnetizing the solenoid; the second solenoid valve is a solenoid valve that closes the second path when energized and opens the second path by a spring force when deenergized; 2. The screw conveyor according to claim 1.

3. The screw conveyor according to claim 1 or 2 is installed. A shield tunneling machine characterized by:

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