Method and device for measuring soil water pressure at the face of a shield tunneling machine

Abstract

To provide a face soil water pressure measuring method and a face soil water pressure measuring device for a shield machine, capable of accurately measuring the soil water pressure acting on the face surface of the shield machine and easily detecting even a small-scale exfoliation of a mass of soil, which prevent a cave-in accident or the like and improve safety during construction.SOLUTION: A pressure sensor 63 housed inside a protective tube (an outer tube 60, and an inner tube 61) projects forward from a face plate 3 provided on a front end face of a shield machine 1, and the pressure sensor 63 measures the ground water pressure. An inner tube 61 is installed inside the outer tube 60, a pressure sensor 63 is housed inside the inner tube 61, and a gel material 64 is filled inside the outer tube 60 and the inner tube 61. While rotating the outer tube 60 and rotating the inner tube 61 and the pressure sensor 63 at a speed different from that of the outer tube 60, the pressure sensor 63 may measure the soil water pressure.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a face soil water pressure measuring method and face soil water pressure measuring device for measuring earth and water pressure in the ground ahead of a shield machine. [Background technology]

[0002] When constructing a tunnel using the shield method, it is necessary to stably maintain the tunnel face of the shield machine so as not to affect the ground surface and to prevent collapse or other problems. To achieve this, it is necessary to grasp the loosening of the ground by measuring the soil and water pressure acting on the tunnel face.

[0003] Conventionally, in order to measure the soil and water pressure acting on the face of a shield tunneling machine, as described in Patent Document 1, a method has been known in which multiple pressure sensors are installed in a partition that defines the back of a chamber formed in the shield tunneling machine. Conventionally, this has been achieved by using a pressure sensor to measure the soil / water pressure inside the chamber, and then adjusting the shield machine's speed and the amount of soil taken in to counteract that pressure, thereby preventing loosening of the ground. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4617909 Summary of the Invention [Problem to be solved by the invention]

[0005] However, although a shield tunneling machine such as that described in Patent Document 1 can measure the soil-water pressure in the chamber, it does not directly measure the ground before it is excavated, and therefore has the following disadvantages: The smaller the scale of soil detachment or collapse that occurs at the tunnel face, the more difficult it is to detect, and even if it is detected, there is a time lag. In the mud pressure method, if the cut soil is not sufficiently mixed in the chamber, it is not possible to detect the soil pressure accurately. (Go to Effects or Examples) Highly sticky soil tends to adhere to the inner surface of the chamber and the pressure sensor, making measurements impossible. (Go to Effects or Examples) When the drilling diameter becomes larger, the pressure difference between the upper and lower parts of the chamber becomes large, making it difficult to manage the pressure at the face.

[0006] The problem that the present invention aims to solve is to provide a method and device for measuring earth and water pressure at the face of a shield machine, which can accurately measure the earth and water pressure acting on the face of a shield machine, make it easy to detect even small-scale soil mass detachment, prevent collapse accidents, etc., and increase safety during construction. [Means for solving the problem]

[0007] The invention of claim 1 is a method for measuring earth and water pressure at the face of a shield machine, in which a pressure sensor stored inside a protective tube is protruded forward from a cutter face provided on the front end surface of the shield machine and the pressure sensor is used to measure the earth and water pressure in the ground, characterized in that a gel material is filled inside the protective tube and the protective tube and the pressure sensor are rotated. The invention of claim 2 is a method for measuring earth and water pressure at the face of a shield machine, in which a pressure sensor stored inside a protective tube is protruded forward from a cutter face provided on the front end surface of the shield machine and the pressure sensor measures the earth and water pressure in the ground, characterized in that the protective tube consists of an outer tube and an inner tube installed inside the outer tube, the pressure sensor is stored inside the inner tube, a gel material is filled inside the outer tube and the inner tube, and the outer tube and the inner tube are rotated. The invention according to claim 3 is a method for measuring earth water pressure at a shield tunneling face of a shield machine as described in claim 2, characterized in that the inner pipe and the outer pipe are rotated at different speeds. The invention of claim 4 is a method for measuring earth water pressure at the face of a shield machine as described in claim 2 or claim 3, characterized in that the outer pipe, inner pipe and pressure sensor are inserted into the ground ahead through the cutter surface by rotating the outer pipe to drill a hole in the ground. The invention of claim 5 is a method for measuring earth and water pressure at the face of a shield machine, in which a pressure sensor housed inside a protective tube is protruded forward from a cutter face provided on the front end face of the shield machine and the pressure sensor is used to measure the earth and water pressure in the ground, characterized in that the protective tube is moved in the axial direction of the shield machine, the pressure sensor is positioned forward from the cutter face to measure the earth and water pressure in the ground, and the pressure sensor is positioned rearward from the cutter face to measure the earth and water pressure in a chamber. The invention of claim 6 is a method for measuring face soil water pressure of a shield machine as described in any one of claims 1 to 5, characterized in that the pressure sensor protrudes forward from the center of the cutter face. The invention of claim 7 is a method for measuring face soil water pressure of a shield tunneling machine as described in any one of claims 1 to 6, characterized in that the pressure sensor is protruded forward through an opening for taking in cutting soil formed on the cutter face. The invention of claim 8 is a method for measuring earth and water pressure at the face of a shield machine as described in any one of claims 1 to 7, characterized in that when the shield machine stops excavating, the protective tube and the pressure sensor are inserted into the ground through the cutter face, the pressure sensor measures the earth and water pressure acting on the ground, and then the protective tube and the pressure sensor are retracted from the cutter face. The invention of claim 9 is a face soil water pressure measuring device that protrudes forward from a cutter face provided on the front end surface of a shield tunneling machine and includes a pressure sensor that measures soil and water pressure in the ground and a protective tube in which the pressure sensor is housed, wherein the protective tube and the pressure sensor are rotatable and the inside of the protective tube is filled with a gel material. The invention of claim 10 is a face soil water pressure measuring device that protrudes forward from a cutter face provided on the front end surface of a shield tunneling machine and includes a pressure sensor that measures soil and water pressure in the ground and a protective tube in which the pressure sensor is housed, wherein the protective tube consists of an outer tube and an inner tube installed inside the outer tube, the pressure sensor is housed inside the inner tube, a gel material is filled inside the outer tube and the inner tube, and the outer tube and the inner tube are rotatable. The invention according to claim 11 is the face soil water pressure measuring device described in claim 10, characterized in that the inner pipe and the outer pipe are rotatable at different speeds. The invention according to claim 12 is the face soil water pressure measuring device according to claim 10 or claim 11, characterized in that the outer pipe is capable of drilling a hole in the natural ground. The invention of claim 13 is a face soil and water pressure measuring device which protrudes forward from a cutter face provided on the front end face of a shield machine and which comprises a pressure sensor which measures soil and water pressure in the ground and a protective tube in which the pressure sensor is housed, wherein the protective tube is movable in the axial direction of the shield machine and which is capable of measuring soil and water pressure in the ground by positioning the pressure sensor forward from the cutter face and capable of measuring soil and water pressure in a chamber by positioning the pressure sensor rearward from the cutter face. The invention according to claim 14 is a face soil water pressure measuring device described in any one of claims 9 to 13, characterized in that the pressure sensor protrudes forward from the center of the cutter face. The invention of claim 15 is a face soil water pressure measuring device described in any one of claims 9 to 14, characterized in that the pressure sensor is removably protruded forward through an opening for taking in cutting soil formed on the cutter surface. The invention of claim 16 is a face soil water pressure measuring device described in any one of claims 9 to 15, characterized in that the protective tube and the pressure sensor are protruded forward of the cutter face so as to be insertable and removable. The following may also be considered as another invention. Means 1 This is a method for measuring earth and water pressure at the face of a shield machine, characterized in that a pressure sensor housed inside a protective tube is protruded forward from a cutter face provided on the front end surface of the shield machine and the earth and water pressure in the ground are measured using the pressure sensor.

[0008] Means 2 The pressure sensor is protruded forward from the center of the cutter surface. Means 1 This is a method for measuring the water pressure at the face of a shield tunneling machine described in the above.

[0009] Means 3 The pressure sensor is protruded forward through an opening formed on the cutter surface for taking in the cutting soil. Means 1 or Means 2 This is a method for measuring the water pressure at the face of a shield tunneling machine described in the above.

[0010] Means 4 The present invention is characterized in that the inside of the protective tube is filled with a gel material, and the protective tube and the pressure sensor are rotated. Either of means 1 to 3 This is a method for measuring the water pressure at the face of the shield tunneling machine described above.

[0011] Means 5 the protective tube comprises an outer tube and an inner tube disposed inside the outer tube, the pressure sensor is housed inside the inner tube, a gel material is filled inside the outer tube and the inner tube, and the outer tube and the inner tube are rotated. Any of the means 1 to 4 This is a method for measuring the water pressure at the face of the shield tunneling machine described above.

[0012] Means 6 The inner tube and the outer tube are rotated at different speeds. Means 5 This is a method for measuring the water pressure at the face of a shield tunneling machine described in the above.

[0013] Means 7 The present invention is characterized in that the outer pipe is rotated to drill a hole in the natural ground, thereby inserting the outer pipe, the inner pipe and the pressure sensor into the natural ground in front through the cutter surface. Means 5 or 6 This is a method for measuring the water pressure at the face of a shield tunneling machine described in the above.

[0014] Means 8 When the shield machine stops excavation, the protective pipe and the pressure sensor are inserted into the ground through the cutter face, and after measuring the soil-water pressure acting on the ground by the pressure sensor, the protective pipe and the pressure sensor are retracted from the cutter face. Any of means 1 to 7 This is a method for measuring the water pressure at the face of the shield tunneling machine described above.

[0015] Means 9 the protective pipe is moved in the axial direction of the shield machine, the pressure sensor is positioned forward from the cutter face to measure the soil-water pressure of the ground, and the pressure sensor is positioned rearward from the cutter face to measure the soil-water pressure in the chamber. Any of means 1 to 8 This is a method for measuring the water pressure at the face of the shield tunneling machine described above.

[0016] means 10 is a face soil / water pressure measuring device that protrudes forward from a cutter face provided on the front end face of a shield tunneling machine and is characterized by having a pressure sensor that measures the soil / water pressure in the ground and a protective tube in which the pressure sensor is housed.

[0017] Means 11 The pressure sensor is protruded forward from the center of the cutter surface. means 10 This is a face soil water pressure measuring device described in the above.

[0018] Means 12 The pressure sensor is removably protruded forward through an opening for taking in cuttings formed on the cutter surface. Means 10 or 11 This is a face soil water pressure measuring device described in the above.

[0019] Means 13 The protective tube and the pressure sensor are rotatable, and the inside of the protective tube is filled with a gel material. Any of means 10 to 12 This is the face soil water pressure measuring device described above.

[0020] Means 14 the protective tube is composed of an outer tube and an inner tube installed inside the outer tube, the pressure sensor is housed inside the inner tube, a gel material is filled inside the outer tube and the inner tube, and the outer tube and the inner tube are rotatable. Any of means 10 to 13 This is the face soil water pressure measuring device described above.

[0021] means 15 The inner tube and the outer tube are capable of rotating at different speeds. Means 14 This is a face soil water pressure measuring device described in the above.

[0022] means 16 The outer pipe is capable of drilling a hole in the natural ground. Means 14 or 15 This is a face soil water pressure measuring device described in the above.

[0023] Means 17 The protective tube and the pressure sensor are protruded forward of the face plate so as to be insertable and removable. Any of means 10 to 16 This is the face soil water pressure measuring device described above.

[0024] Means 18 The protective pipe is movable in the axial direction of the shield machine, and the pressure sensor is positioned forward from the cutter face to measure the soil / water pressure in the ground, and the pressure sensor is positioned rearward from the cutter face to measure the soil / water pressure in the chamber. Any of means 10 to 17 This is the face soil water pressure measuring device described above. Effect of the Invention

[0025] According to the present invention, the pressure sensor protrudes forward from the cutter face of the shield tunneling machine, so that the soil and water pressure in the ground can be measured directly. As a result, the soil and water pressure in the ground can be accurately grasped, and loosening of the ground can be detected early. In addition, compared to those installed inside a chamber, soil and sand are less likely to adhere to the pressure sensor, allowing for more accurate measurements.

[0026] In addition, by having the pressure sensor protrude from the center of the cutter face, the pressure sensor is not affected by the rotation of the cutter face, making it possible to measure soil and water pressure even while the shield machine is operating.

[0027] In addition, by protruding the pressure sensor through an opening formed in the face plate for taking in the cut soil, the pressure sensor can be protruded without drilling a hole in the face plate. Even in the case of a large excavation cross section where a large pressure difference occurs between the top and bottom of the face, the soil and water pressure can be measured above and below, as well as at the center of the cutter face, and the soil and water pressure distribution at the face can be measured.

[0028] In addition, by filling the inside of the protective tube that houses the pressure sensor with a gel material, the pressure sensor is protected by the protective tube, and the gel material prevents soil and sand from entering the protective tube and prevents abrasion of the pressure-receiving surface of the pressure sensor. By measuring the soil and water pressure while rotating the protective tube and the pressure sensor, soil and sand are less likely to adhere to the protective tube and the pressure-receiving surface of the pressure sensor.

[0029] In addition, if the protective tube is made up of an outer tube and an inner tube, the outer tube and the inner tube are rotated, and the pressure sensor is housed inside the inner tube, the durability of the pressure sensor is further increased.

[0030] In addition, by rotating the outer and inner protective tubes at different speeds, soil and sand are less likely to adhere to the pressure sensor housed in the inner tube, enabling more accurate measurements.

[0031] In addition, by rotating the outer pipe to drill a hole in the ground, the outer pipe, inner pipe and pressure sensor protruding forward of the cutter face can be smoothly inserted into the ground.

[0032] In addition, when the shield tunneling machine stops tunneling, the protective tube and pressure sensor can be inserted into the ground through the cutter face, and the soil and water pressure acting on the ground can be measured using the pressure sensor.The protective tube and pressure sensor can then be removed from the cutter face, and the protective tube and pressure sensor can be retracted while the shield tunneling machine is operating so that they do not interfere with the rotation of the cutter face. [Brief description of the drawings]

[0033] [Figure 1] 1 is a cross-sectional view of a shield machine according to a first embodiment of the present invention. [Diagram 2] 1 is a perspective view of a shield machine according to a first embodiment of the present invention. [Diagram 3] 1 is an enlarged cross-sectional view of a main portion of a shield machine according to a first embodiment of the present invention. [Figure 4] FIG. 4 is a perspective view of a shield machine according to a second embodiment of the present invention. [Diagram 5] FIG. 5 is an enlarged cross-sectional view of a main portion of a shield machine according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] Hereinafter, an embodiment of the present invention will be described with reference to the drawings, etc. It should be noted that the present invention is not limited to the embodiment. In the following description, the direction in which the shield machine excavates is referred to as "forward," and the opposite direction is referred to as "backward."

[0035] [First embodiment] A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of a shield tunneling machine according to the first embodiment, FIG. 2 is an oblique view of the shield tunneling machine according to the first embodiment, and FIG. 3 is an enlarged cross-sectional view of a main portion of the shield tunneling machine according to the first embodiment.

[0036] The shield machine 1 according to this embodiment is an earth pressure type shield, and includes a cylindrical body 2 and a circular face plate 3 rotatably provided on the front end surface of the body 2. A partition wall 20 is provided inside the body 2 in parallel with and spaced from the face plate 3 , and a chamber 21 is formed between the partition wall 20 and the face plate 3 .

[0037] The face plate 3 is of a peripheral support type (not shown), and rotates around the central axis of the shield machine 1 as a rotation center when driven by a face plate drive motor. A cutter bit 30 is attached to the front surface of the face plate 3, and an opening 31 is formed adjacent to the cutter bit 30 for taking in the cuttings.

[0038] When the face plate 3 is rotated, the ground facing the face plate 3 is cut by the cutter bit 30, and the excavated soil is taken into the chamber 21 through the opening 31. The excavated soil is mixed with mud-adding materials and the like in the chamber 21 and discharged to the rear by the screw conveyor 5. The front surface of the face plate 3 corresponds to the cutter surface of the present invention.

[0039] The shield machine 1 is provided with a face earth and water pressure measuring device 6 that measures the earth and water pressure at the face in front of the face plate 3. The face earth and water pressure measuring device 6 measures the earth and water pressure in the ground facing the front surface of the face plate 3. The face soil water pressure measuring device 6 measures by having a pressure sensor 63 protrude forward from the center of the face plate 3.

[0040] The face soil water pressure measuring device 6 comprises an outer pipe 60 extending along the central axis of the shield tunneling machine 1 and penetrating the centres of the partition 20, the chamber 21 and the face plate 3, an inner pipe 61 inserted into the inside of the outer pipe 60, a connecting cable pipe 62 inserted into the inside of the inner pipe 61, and a pressure sensor 63 attached to the front end of the connecting cable pipe 62 and stored inside the inner pipe 61, with the outer pipe 60 and inner pipe 61 forming a protective pipe that protects the pressure sensor 63.

[0041] The outer pipe 60, the inner pipe 61 and the connecting cable pipe 62 are made of a strong metal such as steel, and the outer pipe 60 has an inner diameter of about 80 mm, and the inner pipe 61 has an inner diameter of about 60 mm. The pressure sensor 63 attached to the front end of the connection cable pipe 62 has a pressure receiving surface 630 with a diameter of about 25 mm, which is slightly larger than the outer diameter of the connection cable pipe 62 .

[0042] In addition, the front end of the outer tube 60 protrudes 100 mm to 300 mm from the front surface of the face plate 3, the front end of the inner tube 61 protrudes 70 mm to 150 mm from the front surface of the face plate, and the pressure receiving surface 630 of the pressure sensor 63 protrudes 40 mm to 50 mm from the front surface of the face plate 3.

[0043] The outer pipe 60 is rotatably inserted into a front through-hole 300 formed in the center of the face plate 3 and a rear through-hole 200 formed in the center of the partition wall 20. The inner periphery of the rear through-hole 200 is provided with a water-stopping structure such as a seal ring 201 that abuts against the outer periphery of the outer pipe 60, preventing soil and groundwater from entering behind the chamber 21 in the shield machine 1 through the rear through-hole 200.

[0044] An outer tube full-circumference gear 600, which is fixed around the outer periphery of the outer tube 60, is connected to the output shaft of an outer tube drive motor 601 via a reduction gear 602, and by driving the outer tube drive motor 601, the outer tube 60 rotates at a speed of about 10 rpm.

[0045] The inner pipe 61 is rotatably housed inside the outer pipe 60, sharing a central axis. A seal ring 610 is interposed between the inner peripheral surface of the outer pipe 60 and the outer peripheral surface of the inner pipe 61, preventing soil and groundwater from entering the shield machine 1 behind the chamber 21 through the inside of the outer pipe 60.

[0046] The rear of the inner tube 61 protrudes from the rear end of the outer tube 60, and an inner tube full-circumference gear 611 fixedly surrounds the outer periphery of this protruding portion is connected to the output shaft of an inner tube drive motor 612 via a reduction gear 613. By driving the inner tube drive motor 612, the inner tube 61 rotates in the same direction as the face plate 3 and outer tube 60 at a speed of approximately 5 rpm.

[0047] Since the rotation speed of the face plate 3 is about 2 rpm, by rotating the outer pipe 60 and the inner pipe 61 faster, it is possible to promote the separation of the pipes from the soil and prevent the soil from adhering. It is preferable that the face plate 3, the outer tube 60 and the inner tube 61 are rotated at different speeds.

[0048] The connection cable pipe 62 is housed inside the inner pipe 61, and a pressure sensor 63 is fixed to the front end of the connection cable pipe 62 with its pressure-receiving surface 630 facing forward.

[0049] An annular bracket 631 attached to the outer periphery of the rear end of the pressure sensor 63 is fixed to the inner circumferential surface of the inner tube 61. Therefore, when the inner tube 61 rotates, the pressure sensor 63 and the connecting cable tube 62 rotate together.

[0050] The inside of the outer tube 60 and the inner tube 61 are filled with a gel material 64, which prevents soil and sand from entering the inside through the front openings of the outer tube 60 and the inner tube 61 and also protects the pressure-receiving surface 630 of the pressure sensor 63, preventing damage due to abrasion. The gel material 64 may be the same as the tail seal used in a shield tunneling machine (for example, grease, etc.).

[0051] The gel material 64 is continuously filled in the outer tube 60 and the inner tube 61. The gel material 64 may flow out from the front openings of the outer tube 60 and the inner tube 61, but a mechanism is provided that allows the gel material 64 to be continuously added while the outer tube 60 and the inner tube 61 are rotating or stopped by managing the flow rate and pressure, but this mechanism is not shown in the figure. Also, to prevent the filling of the gel material 64 from affecting the measurement of the soil-water pressure, the gel material 64 may be sealed so that it is not filled during measurement, or the soil-water pressure may be measured taking into account the flow rate and pressure related to filling.

[0052] The connecting cable pipe 62 is connected to a cable pipe 65 extending toward the rear of the shield tunneling machine 1 , and the connecting cable pipe 62 and the cable pipe 65 are rotatably connected by a swivel joint 66 .

[0053] Cables for supplying power to the pressure sensor 63 and transmitting and receiving signals are housed inside the cable pipe 65 and the connection cable pipe 62 .

[0054] The front ends of the outer tube 60 and the inner tube 61 may be freely projected from the front surface of the face plate 3, or the amount of projection may be adjustable. In addition, the outer tube 60 and the inner tube 61 may be movable together in the front-rear direction, or may be movable individually.

[0055] Although not shown, the face soil water pressure measuring device 6 is equipped with a frame that supports the outer pipe 60, the inner pipe 61, and a mechanism for driving them. The frame is equipped with bearings that rotatably support the outer pipe 60 and the inner pipe 61. To move the face soil water pressure measuring device 6 in the forward and backward directions (axial direction of the shield tunneling machine 1), it may be moved by wheels attached to the frame, or the outer pipe 60 and the inner pipe 61 may be attached to the frame via a cylinder jack and moved by the cylinder jack.

[0056] When tunneling with the shield machine 1, the outer pipe drive motor 601 is first operated to rotate the outer pipe 60, and a hole is drilled in the ground opposite the front surface of the face plate 3, thereby inserting the outer pipe 60, inner pipe 61 and pressure sensor 63 into the ground. In addition, a drilling bit may be provided at the front end of the outer pipe 60.

[0057] Next, excavation by the shield machine 1 is started, and the outer pipe drive motor 601 and the inner pipe drive motor 612 are driven to rotate the outer pipe 60, the inner pipe 61 and the pressure sensor 63 while the pressure sensor 63 measures the soil-water pressure of the ground.

[0058] Since the protective tube of the face soil / water pressure measuring device 6 is installed at the center of the face plate 3, the face plate 3 can be rotated and the soil / water pressure of the ground can be continuously measured even while the shield machine 1 is excavating.

[0059] Since the outer pipe 60, the inner pipe 61 and the pressure sensor 63 rotate at different speeds, soil and sand are less likely to adhere to the walls of the outer pipe 60 and the inner pipe 61 and the pressure receiving surface 630 of the pressure sensor 63.

[0060] If the pressure sensor 63 is positioned forward of the height from the front surface of the face plate 3 of the cutter bit 30, or forward of the cutting depth, it is possible to measure the soil-water pressure of the ground before excavation without being affected by loosening of the ground caused by the cutter bit 30.

[0061] Second Embodiment The second embodiment of the present invention will be described below with reference to Figures 4 and 5. Note that a description of the same parts as in the first embodiment will be omitted, and differences will be mainly described.

[0062] The shield tunneling machine 1 in the second embodiment employs a plurality of cutter spokes 4 instead of the face plate of the shield tunneling machine in the first embodiment. The cutter spokes 4 are equipped with cutter bits 30. Openings 31 for taking in excavated soil are disposed between the cutter spokes 4. The front surface of the cutter spoke 4 corresponds to the cutter surface of the present invention.

[0063] In the second embodiment, in addition to being installed at the center of the cutter spokes 4, face soil water pressure measuring devices 6 are installed at the openings 31 on both sides (upper and lower) of the center. The face soil water pressure measuring device 6 provided at the center of the cutter spoke 4 is the same as that in the first embodiment.

[0064] The face soil water pressure measuring device 6 installed in the opening 31 is also similar to that in the first embodiment, with an outer tube 60, an inner tube 61 and a pressure sensor 63 protruding forward from the front surface of the cutter spokes 4 through the opening 31 between the cutter spokes 4.

[0065] A rear through-hole 200 is formed in the bulkhead 20 corresponding to the position of the face soil water pressure measuring device 6 protruding from the opening 31, and a guide pipe 67 is inserted into the rear through-hole 200. The gap between the inner periphery of the rear through-hole 200 and the outer periphery of the guide pipe 67 is sealed with a seal ring 201.

[0066] The outer tube 60 is inserted inside the guide tube 67 via a seal ring 670 so as to be rotatable and axially slidable, and the inner tube 61, connecting cable tube 62, and pressure sensor 63 are housed inside the outer tube 60 so as to be rotatable at a speed different from that of the outer tube 60 and to be slidable together with the outer tube 60.

[0067] If the face soil water pressure measuring device 6 protrudes forward through the opening 31 in the face plate 3, the face plate 3 cannot be rotated.

[0068] Therefore, while the cutter spokes 4 of the shield tunneling machine 1 are stopped, the outer pipe 60, inner pipe 61 and pressure sensor 63 are protruded forward from the opening 31 in the face plate 3 to measure the soil-water pressure, and then the outer pipe 60 and the inner pipe 61 and pressure sensor 63 stored inside it are retracted along the guide pipe 67 to a position slightly protruding from the front of the partition 20, and excavation is performed using the shield tunneling machine 1.

[0069] In this state, the pressure sensor 63 protrudes into the chamber 21, making it possible to measure the soil and water pressure in the chamber 21 while the shield machine 1 is operating. This also makes it possible to measure the soil and water pressure in the chamber 21 as in the conventional method. Similarly, with regard to the face soil and water pressure measuring device 6 provided in the center of the cutter spoke 4, by retracting the pressure sensor 63 near the front surface of the partition wall 20, it is possible to switch to the conventional method of measuring the soil and water pressure in the chamber 21.

[0070] In other words, the protective pipes (outer pipe 60, inner pipe 61) are moved in the axial direction of the shield tunneling machine 1, and the pressure sensor 63 is positioned forward of the cutter face to measure the soil / water pressure in the ground, and the pressure sensor 63 is positioned rearward of the cutter face to measure the soil / water pressure in the chamber 21.

[0071] In this way, depending on the condition of the ground being excavated, it is possible to switch between measuring the earth and water pressure at the face in front of the cutter face or in the chamber. For example, when the ground being excavated is of a type where there is a concern of over-intake, the earth and water pressure at the face can be measured in front of the cutter face, and when the ground is of a type where excavation can be performed relatively stably, it can be measured in the chamber. This reduces the period during which the pressure sensor is exposed to the front of the cutter face, lowering the rate of failure of the pressure sensor and other components.

[0072] As in the first embodiment, the face soil and water pressure measuring device 6 installed at the center of the face plate 3 can be protruded forward of the face plate 3 to measure soil and water pressure even while the shield tunneling machine 1 is operating.

[0073] In the second embodiment, face soil and water pressure measuring devices 6 are installed at the center of the face plate 3 and on both sides of the center, so that soil and water pressures at a plurality of distant points can be measured, improving measurement accuracy. If the face soil / water pressure measuring device 6 is arranged in the vertical direction, the soil / water pressure from the top to the bottom of the face can be grasped, thereby improving safety even when excavating a large cross-section tunnel.

[0074] [Other Modifications] The present invention is not limited to the above-mentioned embodiment, and may also include the following, for example.

[0075] In this embodiment, the protective pipe (including the outer pipe, inner pipe and pressure sensor) of the face soil water pressure measuring device is designed not to be inserted or removed rearward from the bulkhead, but it may be made removable so that the face soil water pressure is measured only when necessary. For example, when excavating through gravel or the like that is likely to abrade the pressure receiving surface of the pressure sensor, it is expected that the protective pipe will be retracted rearward from the bulkhead. In this case, shutters may be provided in the through holes in the face plate or bulkhead to prevent soil and sand from getting in. Alternatively, a casing having through holes with shutters in the front and rear side walls may be attached to the rear surface of the bulkhead, and the shutters may be opened and closed sequentially when inserting and removing the protective tube to provide a watertight measure.

[0076] In this embodiment, the outer pipe is rotated to penetrate into the ground, but it is also possible to use a separate boring device to drill a hole in the ground and insert the outer pipe, inner pipe and pressure sensor into this hole.

[0077] In this embodiment, the outer tube and the inner tube are rotated by different drive motors, but the outer tube and the inner tube can also be connected to a single drive motor via different reduction gears and rotated at different speeds.

[0078] In this embodiment, the outer tube and the inner tube are rotated in the same direction, but they may be rotated in opposite directions, which can better prevent soil from adhering to the pressure sensor.

[0079] In this embodiment, the outer tube and the inner tube are rotated in the same direction as the rotation of the face plate, but they may be rotated in different directions. This can prevent soil from adhering to the pressure sensor. Also, by rotating the outer tube in a different direction from the face plate and rotating the inner tube in the same direction as the face plate, soil can be prevented from adhering to the pressure sensor.

[0080] In this embodiment, the rotation mechanism of the cutter of the shield machine is of the peripheral support type, but it is not limited to this. It may have a center shaft and be rotated by a drive motor. In this case, a through hole is provided in the center of the center shaft, and a protective tube containing a pressure sensor is inserted into the through hole.

[0081] In the second embodiment, a total of two sets of face soil water pressure measuring devices are installed at the opening of the face plate, but it is also possible to install one set or three or more sets of face soil water pressure measuring devices.

[0082] The technical aspects of any of the embodiments may be combined to form an embodiment. [Explanation of symbols]

[0083] 1. Shield tunneling machine 2. Torso 20 Bulkhead 200 Rear through hole 201 Seal ring 21 Chamber 3 face plate 300 Front through hole 30 Cutter Bits 31 Opening 4 Cutter Spoke 5. Screw Conveyor 6. Face soil water pressure measuring device 60 outer tube 600 Outer tube full circumference gear 601 Outer tube drive motor 602 Reduction Gear 61 Inner tube 610 Seal ring 611 Inner tube full circumference gear 612 Inner tube drive motor 613 Reduction Gear 62 Connection cable pipe 63 Pressure Sensor 630 Pressure surface 631 Annular bracket 64 Gel Material 65 Cable Pipe 66 Swivel joint 67 Guide tube 670 Seal Ring

Claims

1. A method for measuring earth and water pressure at a face of a shield machine, comprising protruding a pressure sensor housed inside a protective tube forward from a cutter face provided on a front end face of the shield machine, and measuring earth and water pressure in the ground using the pressure sensor, A method for measuring earth water pressure at the face of a shield machine, comprising filling the inside of the protective tube with a gel material and rotating the protective tube and the pressure sensor.

2. A method for measuring earth and water pressure at the face of a shield machine, comprising protruding a pressure sensor housed inside a protective tube forward from a cutter face provided on the front end face of the shield machine, and measuring earth and water pressure in the ground using the pressure sensor, A method for measuring earth water pressure at a shield tunneling machine, characterized in that the protective pipe comprises an outer pipe and an inner pipe installed inside the outer pipe, the pressure sensor is stored inside the inner pipe, a gel material is filled inside the outer pipe and the inner pipe, and the outer pipe and the inner pipe are rotated.

3. A method for measuring earth water pressure at a shield tunneling face of a shield machine according to claim 2, characterized in that the inner pipe and the outer pipe are rotated at different speeds.

4. A method for measuring earth water pressure at the face of a shield tunneling machine as described in claim 2 or claim 3, characterized in that the outer pipe, the inner pipe and the pressure sensor are inserted into the ground in front through the cutter surface by rotating the outer pipe to drill a hole in the ground.

5. A method for measuring earth and water pressure at the face of a shield machine, comprising protruding a pressure sensor housed inside a protective tube forward from a cutter face provided on the front end face of the shield machine, and measuring earth and water pressure in the ground using the pressure sensor, A method for measuring earth and water pressure at the face of a shield machine, characterized by moving the protective pipe in the axial direction of the shield machine, positioning the pressure sensor forward from the cutter face to measure the earth and water pressure in the ground, and positioning the pressure sensor rearward from the cutter face to measure the earth and water pressure in a chamber.

6. 6. A method for measuring earth water pressure at a shield tunneling face of a shield machine according to claim 1, wherein the pressure sensor is protruded forward from the center of the cutter face.

7. A method for measuring earth water pressure at the face of a shield machine as described in any one of claims 1 to 6, characterized in that the pressure sensor is protruded forward through an opening for taking in cutting soil formed on the cutter face.

8. A method for measuring earth and water pressure at the face of a shield machine as described in any one of claims 1 to 7, characterized in that when the shield machine stops excavating, the protective pipe and the pressure sensor are inserted into the ground through the cutter face, the earth and water pressure acting on the ground is measured by the pressure sensor, and then the protective pipe and the pressure sensor are retracted from the cutter face.

9. A face soil water pressure measuring device that is protruded forward from a cutter face provided on the front end face of a shield machine and includes a pressure sensor that measures soil water pressure in the ground and a protective tube that houses the pressure sensor, A face soil water pressure measuring device, characterized in that the protective pipe and the pressure sensor are rotatable, and the inside of the protective pipe is filled with a gel material.

10. A face soil water pressure measuring device that is protruded forward from a cutter face provided on the front end face of a shield tunneling machine and includes a pressure sensor for measuring soil water pressure in the ground and a protective tube in which the pressure sensor is housed, A face soil water pressure measuring device characterized in that the protective pipe consists of an outer pipe and an inner pipe installed inside the outer pipe, the pressure sensor is housed inside the inner pipe, a gel material is filled inside the outer pipe and the inner pipe, and the outer pipe and the inner pipe are rotatable.

11. The face soil water pressure measuring device according to claim 10, characterized in that the inner pipe and the outer pipe are rotatable at different speeds.

12. The face soil water pressure measuring device according to claim 10 or 11, characterized in that the outer pipe is capable of drilling a hole in the natural ground.

13. A face soil water pressure measuring device that is protruded forward from a cutter face provided on the front end face of a shield tunneling machine and includes a pressure sensor for measuring soil water pressure in the ground and a protective tube in which the pressure sensor is housed, The protective pipe is movable in the axial direction of the shield tunneling machine, and the pressure sensor is positioned forward of the cutter face to measure the soil and water pressure in the ground, and the pressure sensor is positioned rearward of the cutter face to measure the soil and water pressure in the chamber.

14. 14. The earth and water pressure measuring device according to claim 9, wherein the pressure sensor protrudes forward from the center of the cutter face.

15. A face soil water pressure measuring device as described in any one of claims 9 to 14, characterized in that the pressure sensor is removably protruded forward through an opening for taking in cutting soil formed on the cutter surface.

16. 16. The face soil water pressure measuring device according to claim 9, wherein the protective pipe and the pressure sensor are protruded forward of the cutter surface so as to be insertable and removable.

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