Shield tunneling machine and calibration method for measurement values ​​in shield tunneling machine

Abstract

To provide a shield excavator and a measured value calibration method for the shield excavator capable of precisely specifying at least density of earth removal for the shield excavator and preventing excavated soil from being excessively captured and the ground surface from sinking (caving in) caused thereby.SOLUTION: A shield excavator 100 comprising a cylindrical skin plate 10, a cutter head 20, a bulk head 11 arranged at the rear of the cutter head 20 and forming a chamber 13, is to produce earth removal by capturing excavated soil in the chamber 13, wherein on a front face 11a of the bulk head 11 opposite to the chamber 13 a cylinder body 12 provided with a pair of cavities 12a arranged with an interval t1 therebetween is attached, and a radiation source 46 constituting an RI density measuring device 40 measuring density of the excavated soil using radio isotope is received in the cylindrical body 12B, and a radiation detector 41 is received in the cylindrical body 12A.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a shield tunneling machine and a method for calibrating measured values in a shield tunneling machine.

Background Art

[0002] In the earth pressure balance shield method, it is important to carry out tunneling of a shield tunneling machine while stabilizing the face and preventing settlement and subsidence on the ground surface within the affected area. For this purpose, it is essential to suppress excessive intake of excavated soil and to grasp the deviation amount of the additive added to the excavated soil taken into the chamber of the shield tunneling machine. In a shield tunneling machine, a screw conveyor formed by a screw and a cylinder that rotatably houses the screw communicates with the chamber, and the muck generated by stirring the excavated soil together with the additive in the chamber is discharged to the screw conveyor and conveyed to the rear of the shield tunneling machine via the screw conveyor. The above-mentioned excessive intake of excavated soil depends on the fact that the volume of the excavated soil or the muck has not been precisely specified. Since the volume of the muck is calculated by dividing its mass by the density, it becomes extremely important to precisely specify the density of the excavated soil or the muck.

[0003] Here, Patent Documents 1 and 2 disclose a technique for measuring the density and water content of excavated soil using radioisotopes (RI: Radioisotope, radioactive isotope) and managing the muck taken into a shield tunneling machine (here, a shield machine). The shield machine described in Patent Document 1 is a shield machine in which a partition is provided at the front of the shield cylinder, a face chamber is provided via this partition, an excavation tool is provided in front of this face chamber, and a muck discharging device is connected behind the face chamber. A density and moisture measuring device using radioisotopes for measuring the density and water content of the soil and sand in the face chamber is provided on the partition.

[0004] On the other hand, the shield machine described in Patent Document 2 is a shield machine equipped with a plastic fluidization measuring device consisting of a rotating shaft that rotates in the mud and measures rotational torque, and a drive device that drives the rotating shaft, and an RI density / moisture meter source sealed inside the rotating body, so that in addition to rotational torque the density and water content of the mud can be measured. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 5-263584 [Patent Document 2] Japanese Patent Publication No. 2003-97181 [Overview of the project] [Problems that the invention aims to solve]

[0006] The shielding machines described in Patent Documents 1 and 2 both employ a technology that involves installing a density and moisture content measuring device using a radioisotope inside the chamber to measure the density and moisture content of the excavated soil stirred inside the chamber. More specifically, there is a cutter spoke in front of the chamber, and a working face (natural ground) in front of the cutter spoke. Radiation (gamma rays and neutrons) is emitted from a source installed in the chamber's partition wall, and the radiation reflected by the cutter spoke and the working face in front of it is detected by a detector. Therefore, the effects of the working face and cutter spokes are reflected in the measurements, making it difficult to accurately measure the density of the excavated soil.

[0007] The present invention aims to provide a shield tunneling machine and a method for calibrating measurements in the shield tunneling machine that can precisely determine at least the density of excavated soil and suppress excessive intake of excavated soil and the resulting ground surface settlement. [Means for solving the problem]

[0008] To achieve the above objective, one embodiment of the shield tunneling machine according to the present invention is: A shield tunneling machine comprising a cylindrical skin plate, a cutter head rotatably mounted in front of the skin plate in the direction of excavation, and a bulkhead mounted behind the cutter head and together with the cutter head and the skin plate forming a chamber, wherein the chamber takes in excavated soil and generates excavated soil, Of the bulkhead, a pair of hollow cylindrical bodies are attached to the front surface facing the chamber, with a gap between them. The RI density measuring device, which measures the density of the excavated soil using radioisotopes, is characterized in that a radiation source constituting the RI density measuring device is housed in one of the cylindrical bodies, and a radiation detector constituting the RI density measuring device is housed in the other cylindrical body.

[0009] According to this embodiment, a pair of hollow cylindrical bodies are attached to the front of the bulkhead facing the chamber with a gap between them. A radioisotope is used to measure the density of excavated soil, and a radioisotope source (gamma-ray source) is housed in one cylindrical body, while a radiation detector (gamma-ray detector) is housed in the other cylindrical body. With the source and radiation detector facing each other with a gap between them, there is no risk of the effects of the working face or cutter spokes being reflected in the measurement values, and the density of the excavated soil (mixed soil after the excavated soil has been stirred in the chamber) can be measured correctly. This makes it possible to suppress excessive intake of excavated soil and the resulting settlement of the ground surface. Furthermore, by measuring the density of the excavated soil mixed in the chamber in real time, it is possible to accurately manage the amount and rate of excavated soil and to ensure stable excavation by the shield tunneling machine.

[0010] Here, "a pair of hollow cylindrical bodies arranged with a gap between them" includes, for example, a configuration in which two cylindrical bodies are arranged with a gap between them in the radial direction (radial direction) on the front surface of a bulkhead, or a configuration in which two cylindrical bodies are arranged with a gap between them, not in the radial direction, but in the circumferential direction, at positions offset by about 1 meter. Furthermore, the cylindrical body is formed from steel pipe or the like, and the length protruding from the bulkhead can be set in the range of approximately 150 mm to 1000 mm. It is also desirable to set the gap between the pair of cylindrical bodies in the range of approximately 50 mm to 700 mm to allow for the flow of excavated soil.

[0011] Furthermore, another embodiment of the shield tunneling machine according to the present invention is: The invention is characterized in that a radiation source and a radiation detector for an RI moisture meter, which measure the water content of the excavated soil, are housed inside the aforementioned cylindrical body or inside a separate cylindrical body.

[0012] According to this embodiment, the radiation source (neutron source) and radiation detector (neutron detector) of an RI moisture meter for measuring the water content of excavated soil are housed inside the cylindrical body or inside a separate cylindrical body, making it possible to determine the properties of the excavated soil with higher precision.

[0013] Here, it is preferable that the cylindrical bodies containing the respective radiation sources for measuring the density and moisture content of the excavated soil be positioned at a distance of 50 cm or more from each other. Specifically, whether the radiation sources for measuring the density and moisture content of the excavated soil are housed inside a common cylindrical body or inside different cylindrical bodies, it is preferable to have a gap of 50 cm or more between the two radiation sources so that the influence of the other radiation source does not affect the measurement values.

[0014] Furthermore, in another embodiment of the shield tunneling machine according to the present invention, The pair of cylindrical bodies and the separate cylindrical body are fixed wings. The cutter head is provided with a plurality of stirring blades on the back surface facing the chamber, and each fixed blade is arranged radially from the bulkhead such that some of the stirring blades pass through the gap between the pair of cylindrical bodies in accordance with the rotation of the cutter head.

[0015] According to this embodiment, a pair of cylindrical bodies are multiple fixed blades arranged radially on the bulkhead such that some of the stirring blades pass through the gaps between them, and a separate cylindrical body is also a fixed blade positioned so as not to interfere with the stirring blades. This allows each fixed blade to have both the function of stirring the excavated soil together with the stirring blades and the function of housing a radiation source or radiation detector. Furthermore, when equipping a separate cylindrical body on the bulkhead, the manufacturing effort and cost of separately positioning the cylindrical body to prevent interference with the rotating stirring blades are eliminated.

[0016] Furthermore, in another embodiment of the shield tunneling machine according to the present invention, The radiation source and the radiation detector are characterized in that they can be easily inserted into and removed from the machine at the rear of the bulkhead, relative to the pair of cylindrical bodies and the separate cylindrical body.

[0017] According to this embodiment, since the radiation source and radiation detector can be easily moved in and out of the machine on the back of the bulkhead into the cylindrical body or a separate cylindrical body, the installation (housing) and removal of the radiation source and radiation detector into the cylindrical body or a separate cylindrical body, and the readjustment of the installation position can be easily performed. This can be achieved by having a fixed wing in the cylindrical body; for example, if the cylindrical body has a stirring blade, it would not be possible to freely insert and remove radiation sources or other components from inside the machine at the back of the bulkhead. Furthermore, if the cylindrical body is a stirring blade or is located on the back of the cutter head, the power supply and signal lines to the radiation detector housed inside the cylindrical body will inevitably pass through the slip rings of the cutter head, etc. This can lead to increased noise interference, potentially reducing the reliability of the measurements detected by the radiation detector, which is undesirable.

[0018] Furthermore, in another embodiment of the shield tunneling machine according to the present invention, A soil intake opening is provided in the aforementioned bulkhead. The aforementioned soil intake port is fitted with a soil intake device that includes at least a first valve located on the bulkhead side, a second valve, and a connecting passage between the first valve and the second valve. Based on the measured value of the excavated soil taken out, the measured value measured by the RI density measuring device is calibrated.

[0019] According to this aspect, an earthwork intake device is attached to the earthwork intake opening provided in the bulkhead, and based on the measured value of the earthwork taken out through the earthwork intake device, the measured value measured by the RI density measuring device is calibrated. As a result, the consistency between the measured value and the measured value can be confirmed almost in real time, and if necessary, the measured value can be calibrated to achieve a more accurate density measurement of the earthwork.

[0020] Also, in another aspect of the shield tunneling machine according to the present invention, the shield tunneling machine further has a measured value calibration device, the measured value calibration device, a storage unit that stores a calibration formula for calibrating the measured values by the RI density measuring device and the RI moisture measuring device; and a calibration unit that, during actual construction, applies the measured value to the calibration formula to obtain a calibration value regarding the density and moisture of the earthwork.

[0021] According to this aspect, in the measured value calibration device, by applying the measured values by the RI density measuring device and the RI moisture measuring device to the calibration formula to obtain a calibration value regarding the density and water content of the earthwork, a calibration value (density and water content of the earthwork) specified by correcting the measured value regarding the radiation intensity (counting rate) with respect to the attenuation of the radiation intensity can be obtained. Since the RI measuring device is an indirect measuring device that uses radiation emitted from a radioisotope, it is necessary to perform a comparison target calibration with a substance whose density and water content are known in advance, obtain a relational expression of the radiation intensity with respect to the density and water content, that is, a calibration formula, and apply the actual measured value to the calibration formula to obtain the density and water content.

[0022] Also, one aspect of the measured value calibration method in the shield tunneling machine according to the present invention is a measured value calibration method for calibrating measured values in the shield tunneling machine, The calibration formula is set based on both the test measurement values ​​obtained by applying the RI density meter and the RI moisture meter to the actual chamber, which is the chamber, or a simulated chamber having the same specifications as the actual chamber, and when soil is excavated experimentally, and the actual measured values ​​of the density and water content of the excavated soil at the time of the test.

[0023] According to this embodiment, by applying an RI density meter and an RI moisture meter to the chamber (actual chamber) used in the actual construction, or a simulated chamber with the same specifications as the actual chamber, test measurements are obtained. By setting a calibration formula based on these test measurements and the actual measured values ​​of density and moisture content of the excavated soil during the test, the density and moisture content of the excavated soil during the actual construction can be determined with high accuracy based on a high-precision calibration formula corresponding to the chamber of the shield tunneling machine used in the actual construction.

[0024] Here, "same specifications as the actual chamber" means that the dimensions of the chamber and the position of the cylindrical body that houses the RI density meter and RI moisture meter, which are attached to the chamber, are the same. Furthermore, "measured values ​​regarding the density and moisture content of the excavated soil during the test" refers to the values ​​obtained when the excavated soil generated during the test was placed separately in a mold or similar and its wet density and moisture content (or moisture content ratio) were measured.

[0025] Furthermore, another aspect of the measurement calibration method for a shield tunneling machine according to the present invention is: The invention is characterized in that the cylindrical body containing the RI density meter and the RI moisture meter is provided in the actual chamber or the simulated chamber at the same position as the installation position in the actual chamber during the actual construction.

[0026] According to this embodiment, by installing a cylindrical body containing an RI density meter and an RI moisture meter at the same position as the actual chamber during construction, in either the actual chamber or a simulated chamber, it becomes possible to determine the density and moisture content of the excavated soil with even greater accuracy, based on a calibration formula that corresponds to the installation positions of the RI density meter and RI moisture meter during construction, in addition to the actual chamber used during construction. Here, when an actual chamber is used, measurements are taken after the start of construction (excavation), and the calibration formula is set after the excavated soil is taken in and measured. Furthermore, preliminary measurements can be taken using full-scale models, in advance at machine manufacturing plants, and during machine assembly at workshops. [Effects of the Invention]

[0027] According to the shield tunneling machine and measurement calibration method for the shield tunneling machine of the present invention, at least the density of excavated soil in the shield tunneling machine can be precisely determined, and excessive intake of excavated soil and the resulting ground surface settlement can be suppressed. [Brief explanation of the drawing]

[0028] [Figure 1] This is a longitudinal cross-sectional view of an example of a shield tunneling machine according to an embodiment. [Figure 2] This is a view taken in the direction of arrow II in Figure 1, and is a front view of the front of the bulkhead as seen from inside the chamber. [Figure 3] This diagram shows the configuration of a pair of fixed wings, each housing a radiation source and a radiation detector that constitute an RI density measuring device. [Figure 4] This diagram shows the RI moisture analyzer's source and radiation detector housed in a separate fixed wing. [Figure 5] This is a magnified view of an example of a soil intake device attached to a soil intake opening in a bulkhead. [Figure 6] This figure shows an example of the hardware configuration of a measurement calibration device. [Figure 7]This figure shows an example of the functional configuration of a measurement value calibration device. [Modes for carrying out the invention]

[0029] The shield tunneling machine and the measurement calibration method for the shield tunneling machine according to the embodiment will be described below with reference to the attached drawings. In this specification and drawings, substantially identical components may be denoted by the same reference numerals to avoid redundant explanations.

[0030] [Shield tunneling machine according to an embodiment and method for calibrating measured values ​​in the shield tunneling machine] Referring to Figures 1 to 7, an example of a shield tunneling machine according to an embodiment and a method for calibrating the measured values ​​in the shield tunneling machine will be described. Here, Figure 1 is a longitudinal cross-sectional view of an example of a shield tunneling machine according to the embodiment, and Figure 2 is a front view of the bulkhead as seen from inside the chamber, as seen from the direction arrow II in Figure 1. Figure 3 shows the state in which the radiation source and radiation detector constituting the RI density measuring instrument are housed in each of a pair of fixed wings, and Figure 4 shows the state in which the radiation source and radiation detector of the RI moisture measuring instrument are housed in a separate fixed wing. Furthermore, Figure 5 is an enlarged view of an example of a soil intake device attached to the soil intake opening in the bulkhead.

[0031] The illustrated shield tunneling machine 100 is an earth pressure balance type shield tunneling machine (including a mud pressure balance type shield tunneling machine) having a shield body 10 made of cylindrical skin plates and a cutter head 20 rotatably mounted in front of the shield body 10 in the direction of excavation, the cutter head 20 having a plurality of cutter spokes 22. Here, the shield tunneling machine may be a slurry type shield tunneling machine equipped with a faceplate-shaped cutter head. Furthermore, the shield tunneling machine may be a folding type shield tunneling machine equipped with a front body and a rear body. In addition, the illustrated example shield tunneling machine 100 may be a shield tunneling machine of various sizes and diameters.

[0032] The shield body 10 is equipped with a bulkhead 11 (partition wall) behind the cutter head 20, and a chamber 13 for taking in excavated soil between the bulkhead 11 and the cutter head 20. Multiple fixed blades 12 are provided on the front surface 11a of the bulkhead 11 facing the chamber 13, and a stirring blade 25 is provided on the back surface 20a of the cutter head 20 facing the chamber 13. A mud additive is supplied to the excavated soil taken into the chamber 13, and the stirring blades 25 are rotated synchronously with the rotation of the cutter head 20 in the X1 direction, causing the excavated soil to plastically flow due to the fixed blades 12 and the rotating stirring blades 25, thereby generating excavated soil.

[0033] Multiple hydraulic motors 14 for driving cutter heads are provided near the center of the rear surface 11b of the bulkhead 11. A screw conveyor 30, which communicates with the chamber 13, extends in an inclined position from below the rear surface of the bulkhead 11 to the rear of the shield body 10. The excavated soil generated by plastic fluidization inside the chamber 13 is transported to the rear of the shield tunneling machine 100 by the screw conveyor 30.

[0034] Multiple shield jacks 16 are attached to the inner circumferential surface of the shield body 10 (only two shield jacks are shown in Figure 1). By extending the shield jacks 16 against the segment ring, which is assembled in a ring shape by an erector device 17 located at the rear of the shield body 10, and pressing against the segment ring, the shield tunneling machine 100 is advanced in the tunneling direction.

[0035] Furthermore, multiple tail seals (not shown) are provided on the rear inner side of the shield body 10, extending in the circumferential direction. The tail seals constantly slide against the installed segment rings, thereby ensuring the watertightness of the shield body 10.

[0036] The cutter head 20 is equipped with multiple cutter spokes 22 extending radially (radially) from a central boss member 24. Multiple cutter bits 23 are attached to the central fishtail 21 and the cutter spokes 22, and copy cutters 23A are retractably mounted on the outer ends of the cutter spokes 22.

[0037] The screw conveyor 30, which receives the excavated soil generated in the chamber 13 and discharges it in the X3 direction to the rear of the shield tunneling machine 100, is formed by a screw 32 having a rotating shaft and spiral blades mounted around it, a cylindrical body 31 that houses the screw 32 so as to be rotatable in the X2 direction, and a drive source (drive motor) not shown that rotates the screw 32.

[0038] Of the multiple fixed wings 12, some are formed from steel tubes with hollow interiors, and openings 11c are provided at the mounting positions of the fixed wings 12 in the bulkhead 11. As will be explained in detail below, the hollow interiors of a pair of fixed wings 12 (an example of a cylindrical body) arranged with a gap between them house a radiation detector 41 and a radiation source 46 (see Figure 3), which constitute the RI density measuring instrument 40, and the hollow interior of another fixed wing 12 (another example of a cylindrical body) houses an RI moisture measuring instrument 50 (see Figure 4).

[0039] The bulkhead 11 is further provided with a soil intake port 11d, and a soil intake device 70 is attached to the soil intake port 11d.

[0040] Figure 2 shows three fixed wings 12, each having a hollow interior 12a. More specifically, a pair of fixed wings 12A and 12B are arranged radially from the center O of the front surface 11a of a bulkhead 11, which is circular in plan view and has a radius r1, with a gap t1 between them. While other fixed wings are also attached to the front surface 11a of the bulkhead 11, these fixed wings do not necessarily need to be cylindrical as they do not house radiation sources or the like. In the illustrated example, a pair of fixed wings 12A and 12B are arranged radially from the center O of the front surface 11a of the bulkhead 11, but the pair of fixed wings 12A and 12B may also be arranged with a gap between them, offset by about 1m in the circumferential direction.

[0041] The relative positions of the fixed blades 12A, 12B and the stirring blade 25 are set such that a single stirring blade 25, which rotates in sync with the rotation of the cutter head 20 in the X1 direction and is located at a radius r2 from the center of rotation O, passes through this gap t1.

[0042] Furthermore, on the front surface 11a of the bulkhead 11, a separate fixed blade 12C, distinct from the pair of fixed blades 12A and 12B, is positioned so as not to interfere with the stirring blade 25 that rotates in the X1 direction or with other stirring blades (not shown).

[0043] The shield tunneling machine 100 is equipped with an RI density meter 40 and an RI moisture meter 50 that measure the density and water content of the excavated soil generated by agitating the excavated soil taken into the chamber 13 using radioisotopes. In other words, when measuring the density and water content of the excavated soil, the shield tunneling machine 100 measures the excavated soil generated in the chamber 13.

[0044] As shown in Figure 3, in the pair of opposing fixed wings 12A and 12B, a radiation source 46 that emits gamma rays and constitutes an RI density measuring device 40 is housed in the hollow 12a inside one fixed wing 12B, and a radiation detector 41 that detects emitted gamma rays and measures the density of excavated soil and constitutes an RI density measuring device 40 is housed in the hollow 12a inside the other fixed wing 12A.

[0045] The gap t1 between the pair of fixed blades 12A and 12B is set to a range of approximately 50 mm to 700 mm, allowing any stirring blade 25 to pass through the gap t1 and the excavated soil to flow. In addition, the protrusion length t3 of the fixed blade 12 from the front surface 11a of the bulkhead 11 is set to a range of approximately 150 mm to 1000 mm.

[0046] Meanwhile, a separate fixed wing 12C houses an RI moisture meter 50 in its hollow interior 12a. Furthermore, the fixed wing 12B, which houses a radiation source 46 for measuring the density of excavated soil, and the fixed wing 12C, which houses a radiation source for measuring the water content, are positioned at least 50 cm apart from each other.

[0047] As shown in Figures 1, 3, and 4, the radiation detector 41, radiation source 46, and RI moisture meter 50 can be moved in and out of the shield tunneling machine 100 in the Y1 direction through the opening 11c of the bulkhead 11 into the hollow 12a of the fixed wing 12 which is specific to each opening 11c.

[0048] The RI density meter 40 has a radiation source 46 that emits gamma rays and a radiation detector 41 that detects the emitted gamma rays to measure the density of the excavated soil. On the other hand, the RI moisture meter 50 has a radiation source 53 that emits neutrons and a radiation detector 52 that detects the emitted neutrons to measure the water content of the excavated soil. The RI density meter 40 and the RI moisture meter 50 will be described in detail below.

[0049] A measurement calibration device 60 is installed inside the shield body 10. The measurement calibration device 60 is a computer that determines the density and water content of excavated soil by applying the respective measurement values ​​from the RI density meter 40 and the RI moisture meter 50 to a calibration formula and obtaining calibration values ​​for the density and water content of the excavated soil. Hereinafter, the measurement calibration device 60 will be described as being installed inside the shield tunneling machine 100, but the measurement calibration device 60 may also be installed in an unillustrated control building on the ground, or it may be installed in both the shield tunneling machine 100 and the control building, and both measurement calibration devices 60 may be connected to enable data transmission and reception.

[0050] As shown in Figure 3, the radiation detector 41 that makes up the RI density meter 40 has a stainless steel shield 43, a gamma-ray detector 44, and a high-voltage power supply 45 inside the case 42.

[0051] On the other hand, the radiation source 46 that constitutes the RI density detector 40 has a gamma-ray source 48 inside the case 47. The radioactive material emitted from the gamma-ray source 48 can be, for example, cobalt 60 (Co·60).

[0052] For example, the PIRICA-S1 (PIRICA is a registered trademark), manufactured by Soil & Rock Engineering Co., Ltd., can be used with this RI density meter 40.

[0053] On the other hand, as shown in Figure 4, the RI moisture detector 50 houses a neutron detector 52 and a neutron source 53 together inside the case 51. The radioactive material emitted from the neutron source 53 can be, for example, californium-252 (cf-252).

[0054] For example, the CONG-II (SRM CONG is a registered trademark) manufactured by Soil & Rock Engineering Co., Ltd. can be used with this RI moisture meter 50.

[0055] Furthermore, regarding the measurement of the water content of the excavated soil using the RI moisture meter 50, fast neutrons emitted from the neutron source 53 collide with the water contained in the excavated soil, and the reflected thermal neutrons are detected by the neutron detector 52, which is attached to the neutron source 53.

[0056] The gamma-ray detector 44 and the neutron detector 52 measure the amount of radiation that has passed through the excavated soil, thereby obtaining measurements regarding the density and water content of the excavated soil. The measurement data obtained by the gamma-ray detector 44 and the neutron detector 52 are converted into electrical signals and input to the measurement calibration device 60 via a cable (not shown). Here, the measurement data converted into electrical signals may be transmitted to the measurement calibration device 60 wirelessly.

[0057] As shown in Figures 1 and 5, the bulkhead 11 has a soil intake port 11d, and a soil intake device 70 is attached to the soil intake port 11d.

[0058] The soil removal and intake device 70 has a first valve 71 located on the bulkhead 11 side, a second valve 72 on the inside of the machine, a T-shaped connecting passage 73 connecting the first valve 71 and the second valve 72, a third valve 74 communicating with the connecting passage 73, and a soil removal port 75 located below the third valve 74. It is preferable that the first valve 71 be a sliding gate valve.

[0059] During excavation, the first valve 71, the second valve 72, and the third valve 74 are all closed. When collecting soil from the chamber 13, the first valve 71 is opened, and the air tube forming the connecting passage 73 is pressurized to correspond to the pressure inside the chamber 13. The air pressure inside the air tube 73 is gradually reduced so that the chamber pressure does not fluctuate, and the air tube 73 is contracted to take in the soil. When pressurizing the air tube, it is desirable to use an incompressible substance such as water or oil.

[0060] Next, the first valve 71 is closed and the third valve 74 is opened to remove the soil into the machine. After removing the soil, the inside of the cylinder containing the air tube 73 is cleaned, and with the third valve 74 still open, the inside of the air tube 73 is pressurized and inflated up to the first valve 71. Finally, the third valve 74 is closed, and preparation for the next soil removal is complete.

[0061] In this configuration, the excavated soil in the chamber 13 is removed into the machine each time via the excavated soil intake device 70, and the measured value measured by the RI density meter 40 is calibrated based on the measured value of the excavated soil. With this configuration, the consistency between the measured value and the actual value can be confirmed in near real time, and the measured value can be calibrated as needed to achieve even higher accuracy in measuring the density of the excavated soil.

[0062] In the shield tunneling machine 100, a pair of hollow cylindrical bodies 12 (fixed wings) with a gap t1 between them are attached to the front surface 11a of the bulkhead 11 facing the chamber 13. A radioisotope source 46, which constitutes an RI density meter 40 that measures the density of excavated soil using radioisotopes, is housed in one cylindrical body 12B, and a radiation detector 41 is housed in the other cylindrical body 12A. Because the source 46 and the radiation detector 41 face each other with a gap t1 between them, there is no risk of the effects of the tunnel face or cutter spokes being reflected in the measurement values, and the density of the excavated soil can be measured correctly. This makes it possible to suppress excessive intake of excavated soil and the resulting settlement of the ground surface.

[0063] Next, the measurement value calibration device 60 will be described with reference to Figures 6 and 7. Here, Figure 6 is a diagram showing an example of the hardware configuration of the measurement value calibration device, and Figure 7 is a diagram showing an example of the functional configuration of the measurement value calibration device.

[0064] As shown in Figure 6, the measurement value calibration device 60 is composed of an information processing device (computer) such as a personal computer (PC). The computer comprising the measurement value calibration device 60 includes a CPU (Central Processing Unit) 61, main memory 62, auxiliary storage 63, input / output IF (interface) 64, and communication IF 65, which are interconnected by a connection bus 66. The main memory 62 and auxiliary storage 63 are recording media that can be read by the computer. Note that each of the above components may be provided individually, or some of the components may be omitted.

[0065] The CPU 61, also known as an MPU (Microprocessor) or processor, may be a single processor or a multiprocessor. The CPU 61 is a central processing unit that controls the entire measurement calibration device 60, which consists of a computer. For example, the CPU 61 expands a program stored in the auxiliary storage device 63 into an executable format in the working area of ​​the main memory device 62, and controls peripheral devices through the execution of the program, thereby providing a function that matches a predetermined purpose.

[0066] The main memory 62 stores computer programs executed by the CPU 61 and data processed by the CPU 61. The main memory 62 includes, for example, flash memory, RAM (Random Access Memory), and ROM (Read Only Memory). The auxiliary storage device 63 stores various programs and various data on a recording medium that can be read and written freely, and is also called an external storage device. The auxiliary storage device 63 stores, for example, the OS (Operating System), various programs, various tables, etc. The OS includes, for example, a communication interface program that exchanges data with external devices connected via the communication IF 65. External devices include, for example, a gamma-ray detector 44 and a neutron detector 52, as well as, for example, a personal computer (not shown) for construction management located in the management building connected to the network.

[0067] The auxiliary storage device 63 is used, for example, as a storage area that assists the main memory 62, and stores computer programs executed by the CPU 61, data processed by the CPU 61, etc. The auxiliary storage device 63 is a silicon disk containing non-volatile semiconductor memory (flash memory, EPROM (Erasable Programmable ROM)), a hard disk drive (HDD), a solid-state drive, etc. Examples of auxiliary storage devices 63 include drives for removable recording media such as CD drives, DVD drives, and BD drives, and examples of removable recording media include CDs, DVDs, BDs, USB (Universal Serial Bus) memory, SD (Secure Digital) memory cards, etc.

[0068] The input / output IF64 is an interface for inputting and outputting data between the measurement calibration device 60 and the connected equipment. For example, keyboards, pointing devices such as touch panels and mice, and input devices such as microphones can be connected to the input / output IF64. The measurement calibration device 60 receives operation instructions from the operator operating the input device via the input / output IF64.

[0069] Furthermore, the input / output IF64 is connected to display devices such as liquid crystal displays (LCDs) and electroluminescent (EL) panels, as well as output devices such as printers and speakers. For example, measurement data regarding density and water content transmitted via cables from gamma-ray detectors 44 and neutron detectors 52 is acquired and displayed. In addition, calibration values ​​(specific values) regarding the density and water content of the excavated soil, obtained by the measurement value calibration device 60, are also displayed on the same screen.

[0070] Communication IF65 is the interface between the measurement calibration device 60 and the cables and networks to which it is connected. Communication IF65 transmits calibration data regarding the density and water content of excavated soil to a personal computer used for construction management in the administration building via various networks, including public networks such as the internet, wireless networks such as mobile phone networks, dedicated networks such as VPNs (Virtual Private Networks), and LANs (Local Area Networks).

[0071] As shown in Figure 7, the measurement value calibration device 60 provides various functions, at least the acquisition unit 602, calibration unit 604, display unit 606, and storage unit 608, through the execution of a program by the CPU 61. Here, at least a portion of the above processing functions may be provided by a DSP (Digital Signal Processor), GPU (Graphics Processing Unit), etc. Similarly, at least a portion of the above processing functions may be provided by a dedicated LSI (large scale integration) such as an FPGA (Field-Programmable Gate Array), numerical arithmetic processor, image processing processor, or other digital circuits.

[0072] The acquisition unit 602 receives measurement data regarding density and water content transmitted via cables, etc., from the gamma-ray detector 44 and the neutron-ray detector 52, and the acquired measurement data is stored (remembered) in the storage unit 608.

[0073] The storage unit 608 stores calibration formulas for calibrating measured values ​​related to density and water content.

[0074] Since the RI density meter 40 and the RI moisture meter 50 are indirect measuring instruments that utilize radiation from radioisotopes, it is necessary to perform a comparative calibration in advance by comparing them with a substance whose density and moisture content are known, and to determine the relationship between the intensity of radiation and density and water content (moisture content), i.e., the calibration formula. In measuring instruments that utilize radiation, regardless of the type of radiation source, the intensity (counting rate) of the radiation is not constant and has the property of decaying over time.

[0075] Therefore, when determining the relationship between radiation intensity (count rate) and density or water content, the absolute value of the radiation intensity (count rate) cannot be used directly, and a correction for the attenuation of radiation intensity is necessary. The calibration formulas for the RI density meter 40 and the RI moisture meter 50 are values ​​unique to each meter. Prior to actual construction, a test is conducted to determine the calibration formula, and the calibration value is determined from the measured values ​​of density and water content using the calibration formula identified in the test.

[0076] Here, the radiation intensity is expressed not as an absolute value, but as a relative value (count rate ratio) of the measurement relative to a certain reference substance. That is, the count rate ratio = measurement value of the excavated soil being measured (count rate (cpm), cpm: counts per minute) / count rate (cpm) measured using the reference substance.

[0077] If the count rate ratio is not used, for example, when the count rate at the time of formula creation is 500 cpm, the wet density: ρt is 2.0 g / cm³. 3 Let's assume that was the case. After some time has passed, ρt remains at 2.0 g / cm³. 3 When measuring materials of the same density, the radiation attenuation can result in values ​​of, for example, 250 cpm, meaning that even though the materials are of the same density, the radiation count (cpm) will differ.

[0078] To avoid such situations, the counting rate ratio is used to take into account the passage of time (radiation decay).

[0079] More specifically, since radiation exists in nature, it is desirable to use the count rate ratio Rρ, which is obtained by subtracting the background (BG) count rate Nρ from the measured count rate Nρ and dividing the result by the standard count rate Sρ, in order to eliminate the influence of this naturally occurring radiation, background (BG). That is, Rρ is given by the following equation (1).

[0080]

number

[0081] From the count rate ratio Rρ calculated by equation (1), the calibration value is calculated from the measured value using the calibration formula shown in equation (2) below.

[0082]

number

[0083] Since the standard calibration constants A and B have unique values ​​depending on the diameter (outer diameter), wall thickness, specifications, etc. of the cylindrical body (pipe) used when measuring the density of excavated soil, it is desirable that the dimensions of the chamber (actual chamber) used in the actual construction and the position of the fixed wings that house the RI density meter 40, etc., be reproduced at the time of factory shipment. In other words, in the calibration formula determination experiment, it is desirable to set the calibration formula using the actual chamber or a simulated chamber with the same specifications as the actual chamber, and furthermore, using the RI density meter and RI moisture meter appropriate for the actual construction.

[0084] For example, when applying a simulated chamber, a more accurate calibration formula can be identified by installing RI density meters and RI moisture meters on the simulated chamber, compared to the multiple fixed wings in the actual chamber used during construction.

[0085] In the calibration formula determination experiment, an RI density meter and an RI moisture meter are applied to an actual chamber or a simulated chamber with the same specifications as the actual chamber. The calibration formula is then established based on both the test measurements taken with these RI density meters and RI moisture meters when soil is excavated experimentally, and the actual measured values ​​of the density and moisture content of the excavated soil during the test.

[0086] In the calibration formula identification experiment, measurements are taken using an RI density meter or similar device when excavated soil (simulated excavated soil) expected during actual construction is generated in the actual chamber or a simulated chamber. Furthermore, actual values ​​are determined based on the wet density measurement and water content measurement of the generated excavated soil.

[0087] In creating the simulated excavated soil, the target site for the actual construction is assumed, and gravel, sand, and soil are mixed in predetermined proportions. Furthermore, the thickening agent (mud thickener) used in the actual construction is added at this stage.

[0088] Furthermore, according to the inventors, the properties (type) of the excavated soil have almost no effect on the accuracy of the calibration formula; it has been determined that only the density and water content of the excavated soil affect the accuracy of the calibration formula.

[0089] The storage unit 608 stores the calibration formulas for the RI density meter 40 and the RI moisture meter 50, which are set in the calibration formula identification experiment and are suitable for use in the actual construction.

[0090] During actual construction, measured data regarding the density and moisture content of the excavated soil are stored in the storage unit 608 as needed. The calibration unit 604 obtains the actual measured values ​​for the density and moisture content of the excavated soil taken in via the excavated soil intake device 70 each time. If necessary, it applies the measured data to the calibration formulas for density and moisture content stored in the storage unit 608 to determine the calibration values ​​for density and moisture content, thereby obtaining measured values ​​that better reflect the actual measured values. The above describes the measurement calibration method for the shield tunneling machine according to this embodiment.

[0091] The display unit 606 displays calibration values ​​for the specified density and water content on the screen, identifies the volume of excavated soil calculated based on the calibration values, and displays the basis for verification regarding whether or not excessive excavated soil has been taken into the chamber 13. In addition, the appropriate range for the amount of excavated soil to be taken is stored in the storage unit 608, and a determination unit (not shown) may periodically compare the amount of excavated soil to be taken, calculated from the density of the specified excavated soil (and thus the excavated soil), with the appropriate range for taking the soil, and display the determination result on the display unit 606.

[0092] According to the shield tunneling machine 100 and the measurement calibration method, the density of excavated soil and water content in the shield tunneling machine 100 can be precisely determined, making it possible to effectively suppress excessive intake of excavated soil and the resulting ground surface settlement.

[0093] Furthermore, other embodiments may be used in which other components are combined with the configurations listed in the above embodiments, and the present invention is not limited in any way to the configurations shown herein. In this regard, modifications can be made without departing from the spirit of the present invention, and can be appropriately determined according to the application form. [Explanation of Symbols]

[0094] 10: Shield body (cylindrical skin plate) 11: Bulkhead 11a:Front 11b: Back 11c: Opening 11d: Soil intake 12:Fixed wing 12A, 12B: Fixed wing (cylindrical body) 12C: Separate fixed wing (fixed wing, tube) 12a:Hollow 13: Chamber 14: Hydraulic motor for driving the cutter head 16: Shield Jack 17: Erecta equipment 18: Folding jack 20: Cutter head 21: Fishtail 22: Cut Spoke 23: Cutter Bit 23A: Copy cutter 24: Boss component 30: Screw conveyor 31: Cylinder 32: Screw 33: Rotation axis 34: Spiral feather (feather) 40:RI density measuring device 41: Radiation detector 42: Case 43: Shield 44: Gamma-ray detector 45: Power supply 46: Line source 47: Case 48: Radiation source (gamma ray source) 50:RI moisture meter 51: Case 52: Radiation detector (neutron detector) 53: Radiation source (neutron source) 60: Measurement Calibration Device 602: Acquisition Department 604: Proofreading Department 606: Display section 608: Storage Unit 70: Soil removal and intake device 71: Valve No. 1 72: Second valve 73: Connecting path (air tube) 74: Third valve 75: Soil removal port 100: Shield tunneling machine

Claims

1. A shield tunneling machine comprising a cylindrical skin plate, a cutter head rotatably mounted in front of the skin plate in the direction of excavation, and a bulkhead mounted behind the cutter head and together with the cutter head and the skin plate forming a chamber, wherein the chamber takes in excavated soil and generates excavated soil, Of the bulkhead, a pair of hollow cylindrical bodies are attached to the front surface facing the chamber, with a gap between them that allows the excavated soil to flow. A shield tunneling machine characterized in that a radiation source constituting an RI density meter, which measures the density of the excavated soil using a radioisotope, is housed in one of the cylindrical bodies, and a radiation detector constituting the RI density meter is housed in the other cylindrical body.

2. The shield tunneling machine according to claim 1, characterized in that a radiation source and a radiation detector for an RI moisture meter, which measure the water content of the excavated soil, are housed inside the aforementioned cylindrical body or inside a separate cylindrical body.

3. The pair of cylindrical bodies and the separate cylindrical body are fixed wings. The shield tunneling machine according to claim 2, characterized in that a plurality of stirring blades are provided on the back surface of the cutter head facing the chamber, and each fixed blade is arranged radially of the bulkhead such that some of the stirring blades pass through the gap between the pair of cylindrical bodies in accordance with the rotation of the cutter head.

4. The shield tunneling machine according to claim 2, characterized in that the radiation source and the radiation detector can be moved in and out of the machine on the back of the bulkhead relative to the pair of cylindrical bodies and the separate cylindrical body.

5. A soil intake opening is provided in the aforementioned bulkhead. The aforementioned soil intake port is fitted with a soil intake device that includes at least a first valve located on the bulkhead side, a second valve, and a connecting passage between the first valve and the second valve. The shield tunneling machine according to claim 4, characterized in that the measured value measured by the RI density meter is calibrated based on the measured value of the excavated soil.

6. The aforementioned shield tunneling machine further includes a measurement calibration device, The aforementioned measurement value calibration device is A storage unit for storing a calibration formula for calibrating the measured values ​​obtained from the RI density meter and the RI moisture meter, The shield tunneling machine according to claim 5, further comprising a calibration unit that, during actual construction, applies the measured values ​​to the calibration formula to obtain calibration values ​​for the density and moisture content of the excavated soil.

7. A method for calibrating the measured values ​​in the shield tunneling machine according to claim 6, A method for calibrating measurement values ​​in a shield tunneling machine, characterized in that the RI density meter and the RI moisture meter are applied to the actual machine chamber, which is the chamber, or a simulated chamber having the same specifications as the actual machine chamber, and the calibration formula is set based on both the test measurement values ​​measured by the RI density meter and the RI moisture meter when soil is excavated experimentally, and the actual measured values ​​regarding the density and water content of the excavated soil at the time of the test.

8. A method for calibrating measurement values ​​in a shield tunneling machine according to claim 7, characterized in that the cylindrical body containing the RI density meter and the RI moisture meter is provided in the actual machine chamber or the simulated chamber at the same position as the installation position in the actual machine chamber during actual construction.

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