Installation structure for acceleration sensor of shield machine

Abstract

To enable easy fixing of an acceleration sensor to an acceleration-detection bit as a unified body without defects by a simple operation performed on the rear-face side of a cutter head.SOLUTION: An installation structure 40 unifies and fix an acceleration sensor 14 to acceleration-detection bits 41, 42 that are arranged on the cutter head 13 of a shield machine 11 and fastened protruding forward from the front plate 43a of the cutter spoke 43. A mounting sheath 46 of an acceleration-detection fixture 44 is inserted and mounted in a mounting-fixation hole 43b; a joint base board 45 is butted with the rear face of the front plate 43 with bolt-insertion holes 45a aligned to bolt-tightening holes 43c; and then the acceleration-detection fixture 44 is fixed to the front plate 43a with tightening bolts 47 to install and fix as a unified body the acceleration sensor 14 to the fixation bases 41a, 42a of the acceleration-detection bits 41, 42.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an acceleration sensor mounting structure and method for a shield tunneling machine, and in particular to an acceleration sensor mounting structure and method used in a sealed shield tunneling machine equipped with a face soil distribution discrimination system that enables discrimination of the soil distribution of the ground at the face. [Background technology]

[0002] In recent years, for example, in urban areas, there has been a demand for longer shield tunnels due to shaft land issues and congestion with underground buried objects. When constructing longer shield tunnels, the soil quality of the ground at the tunnel face often changes as the shield machine excavates. Furthermore, when the shield machine excavates the boundary between layers of different soil types, for example, layered vertically or horizontally, different soil types may appear simultaneously on the same tunnel face being cut.

[0003] When a shield machine excavates an area where ground has different soil types, for example, if one type of ground is bedrock or the like and is significantly harder than the other type of ground, and the soil conditions at the tunnel face are not properly understood, the shield machine is likely to run over or skid on the hard ground, making it difficult to accurately maintain the vertical and horizontal alignment of the shield tunnel. For this reason, there is a need for technology that allows the shield machine to stably manage its excavation in accordance with the ground conditions by understanding the soil conditions at the tunnel face as a whole and controlling it to prevent running over or skidding on the hard ground, for example by increasing the amount of overcut by the copy cutter in areas of hard ground.

[0004] In particular, with conventional sealed shield tunneling machines, which rotate the cutter head attached to the tip of the shield body to excavate while cutting the face, changes in the soil quality at the face are generally evaluated by, for example, examining the properties of the cut soil discharged from a compartment, or measuring the earth pressure at the face and the cutter torque value of the cutter head.However, with such evaluation methods, it is difficult to grasp the soil quality at the face as a whole and properly distinguish the distribution of different soil types at the face.

[0005] For this reason, the applicant of the present application has proposed, for example in Patent Document 1 described below, a system for determining the soil distribution at the face of a shield tunnel using a simple configuration that enables the ground condition at the face of the tunnel to be accurately grasped in real time and across the entire tunnel while the cutter head is cutting, thereby enabling more stable management of the shield tunneling machine's excavation.

[0006] The system for determining the soil type distribution at the face using a shield tunneling machine described in Patent Document 1 comprises an acceleration sensor attached to the outer periphery of the cutter head and a computer connected to the acceleration sensor. The computer is equipped with a vibration data memory unit that stores cutting vibration data sent from the acceleration sensor when the face is cut by a bit for each predetermined rotation angle of the cutter head, and a vibration data display unit that displays the cutting vibration data for each rotation angle stored by the vibration data memory unit as a cutting vibration distribution distributed circumferentially around a circle that resembles the face cross section.The system makes it possible to determine the boundary between different soil types in the ground at the face from the points where the wave state of the distribution in the circumferential cutting vibration distribution displayed by the vibration data display unit changes. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 6342723 Summary of the Invention [Problem to be solved by the invention]

[0008] However, in the system for determining face soil distribution described in Patent Document 1, the acceleration sensor is attached to the outer edge of the cutter head, separate from the bit, and mainly measures vibrations from the outer bit only.In addition, the measurement value includes vibrations from bits surrounding the outer bit, not just the outer bit, which are transmitted through the cutter head.This creates a technical problem in that, depending on the ground, it may be difficult to detect vibrations accurately.Therefore, it is desirable to fix the acceleration sensor as an integral part of the acceleration detection bit itself, where vibrations are measured, so that the vibrations of the acceleration detection bit while cutting the ground can be measured accurately.

[0009] On the other hand, one possible method for fixing an acceleration sensor integrally to a bit attached to the front panel of a cutter head is to fix the acceleration sensor to the bit in advance to make it an acceleration detection bit before attaching the bit to the cutter head, and then fix the formed acceleration detection bit in a predetermined position on the front panel of the cutter head.However, there is a risk that malfunction will occur in the acceleration sensor that has been fixed integrally to the bit in advance due to the heat and electrical effects generated when fixing the acceleration detection bit to the front panel of the cutter head by welding, etc.

[0010] In response to this, it is conceivable to first fasten and attach the acceleration detection bit, which measures vibrations, to the front panel of the cutter head by welding or the like, and then work from the back side of the front panel to fix the acceleration sensor to the attached acceleration detection bit as a single unit.However, since work on the back side of the front panel would be carried out in a narrow work space, for example, inside the cutter spokes that make up the cutter head, there is a need to develop a technology that allows the acceleration sensor to be easily fixed as a single unit to the acceleration detection bit in a specified orientation using a simpler method, even in a narrow work space.

[0011] The present invention aims to provide an acceleration sensor mounting structure and method for a shield tunneling machine that enable an acceleration sensor to be easily and smoothly fixed as a single unit to an acceleration detection bit attached to the front plate of the cutter head through simple work from the back side of the front plate, without causing any problems due to heat or electricity caused by welding, etc. [Means for solving the problem]

[0012] The present invention relates to a shield tunneling machine equipped with a face soil distribution determination system including an acceleration sensor attached to a cutter head and a computer connected to the acceleration sensor, and provides an acceleration sensor mounting structure for a shield tunneling machine for mounting and fixing the acceleration sensor as an integral part to a bit disposed on the cutter head, wherein the acceleration detection bit to which the acceleration sensor is attached is fixed to a front plate of a cutter spoke constituting the cutter head in a state where it protrudes forward from the front plate, the acceleration sensor is housed in a fixed state inside an acceleration detection jig consisting of a metal joint base part and a mounting erected part erected from the joint base part, and is attached as an integral part to the acceleration detection bit via the acceleration detection jig, and the front plate of the cutter spoke is provided with a mounting part for mounting the acceleration sensor. The above-mentioned object is achieved by providing an acceleration sensor mounting structure for a shield tunneling machine in which the acceleration sensor is attached as a unit to the acceleration detection bit by providing a mounting hole for fastening the mounting erection portion of the acceleration detection jig, the mounting hole for fastening the mounting erection portion of the acceleration detection jig to the mounting position of the detection bit ...

[0013] Furthermore, it is preferable that the mounting structure of the acceleration sensor in the shield tunneling machine of the present invention is such that the wiring connected to the acceleration sensor is routed inside the mounting upright portion via a connector provided on the joint base portion of the acceleration detection jig, and is extended through the hollow interior of the cutter spoke and connected to the computer.

[0014] In addition, in the mounting structure of the acceleration sensor in the shield tunneling machine of the present invention, it is preferable that the inside of the mounting upright portion of the acceleration detection jig in which the acceleration sensor is housed is filled with a filling solidifying agent.

[0015] Furthermore, in the mounting structure of the acceleration sensor in the shield tunneling machine of the present invention, it is preferable that the mounting erection portion of the acceleration detection jig is inserted and mounted into the mounting fixing hole with adhesive applied to its outer peripheral surface.

[0016] Furthermore, the present invention provides a method for constructing an acceleration sensor mounting structure in the above-mentioned shield tunneling machine, in which the bit is disposed in the cutter head, and the mounting fixing hole and the bolt fastening hole are formed at the mounting position of the acceleration detection bit, and then the acceleration detection jig, in which the acceleration sensor is housed in a fixed state inside the mounting erection portion, is fastened and fixed to the front panel using a fastening bolt, thereby achieving the above-mentioned object.

[0017] Furthermore, in the method of constructing the acceleration sensor mounting structure in the above-mentioned shield tunneling machine of the present invention, it is preferable that the cutter spoke has a hollow cross-sectional shape that allows a worker to enter, and that the worker enters the inside of the cutter spoke and mounts and fixes the acceleration sensor as a single unit to the acceleration detection bit.

[0018] In addition, in the method for constructing the acceleration sensor mounting structure in the above-mentioned shield tunneling machine of the present invention, it is preferable that an openable and closable working window is provided on the back panel of the cutter spoke, and the acceleration sensor is attached and fixed as a unit to the acceleration detection bit by working through the working window. [Effects of the Invention]

[0019] According to the acceleration sensor mounting structure for a shield tunneling machine and the acceleration sensor mounting method for a shield tunneling machine of the present invention, the acceleration sensor can be easily and smoothly fixed as a single unit to the acceleration detection bit attached to the front plate by simple work from the back side of the front plate of the cutter head, without causing any problems due to heat or electricity caused by welding, etc. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is an explanatory diagram illustrating the configuration of a system for determining face soil distribution using a shield machine, in which an acceleration sensor mounting structure for a shield machine according to a preferred embodiment of the present invention is used. FIG. [Figure 2] FIG. 2 is a front view of the shield tunneling machine. [Figure 3] FIG. 3 is an enlarged cross-sectional view taken along the line AA in FIG. 2. [Figure 4] (a) is a partially broken front view illustrating the mounting structure of an acceleration sensor in a shield tunneling machine according to a preferred embodiment of the present invention, (b) is a cross-sectional view along BB in (a), and (c) is a top view of (a) viewed from above. [Figure 5] (a) is a cross-sectional view along CC in (b) of the acceleration detection jig housing the acceleration sensor before the lid plate is attached, (b) is a cross-sectional view along DD in (a) with the lid plate attached, (c) is an enlarged cross-sectional view along EE in (a) with the lid plate attached, and (d) is an enlarged cross-sectional view along FF in (a). [Figure 6](a) is a front view explaining the acceleration sensor, (b) is a side view of (a) seen from the left, (c) is a side view of (a) seen from the right, and (d) is a top view of (a) seen from above. [Figure 7] 10 is an explanatory diagram illustrating an example of a display screen by a vibration data display unit and a boundary line display unit. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0021] The mounting structure for an acceleration sensor in a shield machine according to a preferred embodiment of the present invention (see Figures 4(a) and (b)) is used, for example, in the system 10 for determining face soil type distribution using a shield machine shown in Figure 1, as a mounting structure for integrally fixing an acceleration sensor 14 (see Figures 6(a) to (d)) to acceleration detection bits 41, 42 (Figure 2) attached to the cutter head 13 of the shield machine 11. In this embodiment, the system 10 for determining face soil type distribution using a shield machine is a closed-type shield machine, and in construction work to build a shield tunnel using, for example, a mud pressure type shield machine 11, it makes it possible to accurately grasp the condition of the ground 12a, 12b, 12c on the face 12 during cutting in real time and across the entire surface, and for example, when the shield machine 11 excavates a boundary portion between grounds 12a, 12b, 12c of different soil types, it is possible to determine the soil type of one ground 12a. Even in the case of bedrock or the like which is considerably harder than the soil of the other ground 12b, 12c, which is made up of sandy soil, clayey soil, etc., the shield tunneling machine 11 can be controlled to prevent climbing over or sliding sideways on the hard ground 12a by, for example, increasing the amount of overcut by the copy cutter 16a (see Figure 2) in the hard ground 12a, thereby enabling more stable excavation management according to the conditions of the ground 12a, 12b, 12c.

[0022] That is, in this embodiment, the face soil quality distribution discrimination system 10 is designed to accurately grasp the condition of the ground 12a, 12b, 12c at the face 12, and to avoid, for example, climbing over or sliding on hard ground 12a, by accurately determining the condition of the ground 12a, 12b, 12c at the face 12, thereby enabling the shield tunnel to accurately maintain its longitudinal and horizontal alignment. This is because, for example, in urban areas, due to issues such as the lack of space for shafts and congestion with underground buried objects, it is desirable to construct long shield tunnels using not only large-diameter shield machines but also small- and medium-diameter shield machines. When constructing long shield tunnels, it is expected that the shield machine 11 will often be used to excavate the boundary areas of overlapping ground 12a, 12b, 12c of different soil types.

[0023] Furthermore, as shown in Figures 2 and 4(a) to (c), the face soil distribution discrimination system 10 uses an acceleration sensor 14 (see Figures 4(a) and (b)) integrally provided on a bit 16 (acceleration detection bits 41, 42) attached to the cutter head 13 of the shield tunneling machine 11, and preferably while referring to a columnar diagram of the surrounding ground, enables the condition of the ground 12a, 12b, 12c on the face 12 being cut by the cutter head 13 to be grasped more accurately and thoroughly in real time and on a planar basis.

[0024] Furthermore, the system 10 for determining the soil distribution at the face using a shield machine is, as shown in Figures 1 to 4, a determination system that is installed on an enclosed shield machine 11 which has a rotating cutter head 13 at the tip of the shield body 15 and excavates while cutting the face 12 using a plurality of bits 16 attached to the cutter head 13, and is capable of determining the soil distribution of the ground 12a, 12b, 12c at the face 12, and is equipped with acceleration sensors 14 (see Figures 4(a) and (b)) that are integrally attached to two or more acceleration detection bits 41, 42 (see Figure 2) selected from the plurality of bits 16 and fixed to the front panel 43a of the cutter spokes 43 that constitute the cutter head 13 in a state of protruding forward from the front panel 43a, and a computer 20 (see Figure 1) connected to these acceleration sensors 14. The two or more acceleration detection bits 41, 42 include an outer peripheral acceleration detection bit 41 arranged on the outer periphery of the cutter head 13 and an intermediate acceleration detection bit 42 arranged in an intermediate region between the center and outer periphery of the cutter head 13. The computer 20 is equipped with a vibration data storage unit 21 that stores cutting vibration data sent from the acceleration sensors 14 attached to the outer peripheral acceleration detection bit 41 and the intermediate acceleration detection bit 42 when cutting the cutting face 12 with these acceleration detection bits 41, 42 for each predetermined rotation angle of the cutter head, and a vibration data display unit 22 that displays the cutting vibration data for each rotation angle stored by the outer peripheral acceleration detection bit 41 and the intermediate acceleration detection bit 42 in the vibration data storage unit 21 as a plurality of concentric annular cutting vibration distributions 23a, 23b (see FIG. 7) distributed in the circumferential direction of a circle simulating the cutting face cross section. The boundary portions of different soil types in the ground 12a, 12b, 12c of the working face 12 can be identified from the points 24a, 24b where the wave state of the distribution fluctuates in the circumferential cutting vibration distributions 23a, 23b displayed by the vibration data display unit 22.

[0025] In addition, in the system 10 for determining the soil distribution at the face using a shield tunneling machine, the vibration data display unit 22 is configured to display the distribution of vibration acceleration (ground response acceleration during cutting) for each rotation angle as multiple concentric circular cutting vibration distributions 23a, 23b.

[0026] Furthermore, in the system 10 for determining the soil distribution at the face using a shield machine, as shown in Figure 1, an auxiliary acceleration sensor 18 connected to a computer 20 is attached to the inner wall surface of the shield body 15, preferably to the back part of a partition 17 provided on the shield body 15, and the vibration data display unit 22 is configured to display the cutting vibration data for each rotation angle as multiple concentric ring-shaped cutting vibration distributions 23a, 23b, with noise and mechanical vibrations removed using the main body vibration data sent from the auxiliary acceleration sensor 18.

[0027] In this embodiment, the shield machine 11 is a sealed shield machine, such as a known mud pressure type shield machine. In the mud pressure type shield machine 11, a partition wall 17 is provided behind the cutter head 13 at the tip of the shield body 15 to form a compartment 19 that is filled by mud pressure, and the center shaft 13a of the cutter head 13 is attached and supported by this partition wall 17. Also provided inside the shield body 15 are a mud removal mechanism (not shown), a rotary drive motor (not shown), a shield jack (not shown), an erector (not shown), etc.

[0028] The computer 20 constituting the face soil distribution determination system 10 is a well-known device that functions as a database server, and can be, for example, a personal computer. The database server computer 20 includes a CPU, ROM, RAM, I / F, storage means, input means, display means, output means, etc. The CPU of the database server controls the overall operation of the database server using the RAM as a work area in accordance with a control program stored in the ROM. The CPU also functions as storage means, input means, display means, output means, etc., by storing various computer programs in the ROM. The vibration data storage unit 21 (described later) stores cutting vibration data sent from the acceleration sensor 14 together with the rotation angle of the cutterhead 13. The vibration data display unit 22 displays the cutting vibration data stored in the vibration data storage unit 21 on the display 20a as cutting vibration distributions 23a and 23b distributed in the circumferential direction, or outputs the data from a printer (not shown).

[0029] The computer 20 also incorporates a known shield tunneling management system that can centrally manage measurement values collected from various measuring instruments used in the shield tunneling method and survey values entered via input means. The shield tunneling management system has the following functions: centrally manages measurement values collected from various measuring instruments used in the shield tunneling method, organizes the information, and provides it to engineers and workers to support on-site construction management; estimates the condition of the ground, the condition of excavated soil, and the installation status of the shield tunneling machine based on changes over time and the results of statistical processing; and calculates the position of the shield tunneling machine and segments by inputting measurement results and determining the deviation from the baseline. The "Shield Tunneling Management System" manufactured by Sensaku Kobo Co., Ltd. can be preferably used as such a shield tunneling management system.

[0030] Furthermore, the computer 20 is installed in an operation control room 30 located on the ground, and the computer 20 installed in the operation control room 30 is connected to various measuring instruments, the acceleration sensor 14 and auxiliary acceleration sensor 18 described below, for example, via acceleration sensor amplifiers 25a, 25b, and via a known transmission system 29 equipped with a control panel 26 made of PCL, a sequencer panel 27, a remote operation panel 28, etc.

[0031] The acceleration sensor 14 and auxiliary acceleration sensor 18, which together with the computer 20 constitute the face soil distribution determination system 10, can be any of a variety of known acceleration sensors that detect acceleration, which is the rate of change of velocity over time (time derivative). The acceleration sensor 14 is used to measure the value of acceleration itself and detect the application of an external force, using the physical law that the acceleration acting on an object is proportional to the external force applied. The acceleration sensor 14 and auxiliary acceleration sensor 18 can be used in scientific experiments requiring high-precision measurements, gravity measurement, earthquake measurement, and other applications, as well as various acceleration sensors that can detect tilt, vibration, movement, impact, and fall. More specifically, various triaxial piezoelectric acceleration detectors manufactured by Showa Sokki Co., Ltd., which can accurately detect vibration magnitude and frequency, can be used as such acceleration sensors.

[0032] The acceleration sensor 14 is attached and fixed integrally to each of the outer acceleration detection bit 41 and the middle acceleration detection bit 42 (see Figure 2) as bits 16 arranged on the cutter head 13 of the shield tunneling machine 11 using an acceleration detection jig 44 (see Figures 5(a) to (d)) described later, using an acceleration sensor mounting structure 40 according to a preferred embodiment of this embodiment shown in Figures 4(a) to (c).

[0033] That is, the acceleration sensor mounting structure 40 for a shield machine of this embodiment is a mounting structure for mounting and fixing the acceleration sensor 14 integrally to the bit 16 (acceleration detection bits 41, 42) disposed on the cutter head 13 (see Figure 2) in a shield machine 11 equipped with a face soil distribution determination system 10 (see Figure 1) that includes the acceleration sensor 14 attached to the cutter head 13 and a computer 20 connected to the acceleration sensor 14. As shown in Figures 3 and 4(a) and (b), the acceleration sensor mounting structure 40 for a shield machine of this embodiment is fixed to the front plate 43a of the cutter spokes 43 (see Figure 2) that constitute the cutter head 13, with the acceleration detection bits 41, 42 to which the acceleration sensor 14 is attached protruding forward from the front plate 43a.

[0034] As shown in Figures 5(a) to 5(d), the acceleration sensor 14 is fixedly housed in the inner tip portion of an acceleration detection jig 44, which consists of a metal joint base portion 45 and a mounting portion 46 extending from the joint base portion 45. The acceleration detection jig 44 is attached to the acceleration detection bits 41 and 42 via the acceleration detection jig 44. Mounting holes 43b are formed in the front plate 43a of the cutter spoke 43 at the mounting positions of the acceleration detection bits 41 and 42, through which the mounting portions 46 of the acceleration detection jig 44 are inserted and fixed. The mounting holes 43b penetrate the mounting bases 41a and 42a of the acceleration detection bits 41 and 42 to a depth that penetrates the mounting holes 43b. Multiple bolt fastening holes 43c are formed on the back side of the mounting hole 43b in an outer peripheral region surrounding the mounting hole 43b. Multiple bolt insertion holes 45a are formed in the joint base portion 45 of the acceleration detection jig 44 in an outer peripheral region surrounding the mounting portion 46. The mounting stand 46 is inserted and attached into the mounting fixing hole 43b, and the bolt insertion hole 45a is aligned with the bolt fastening hole 43c, and the joining base part 45 is overlapped with the front plate 43a from the back side. Then, the acceleration detection jig 44 is fastened and fixed to the front plate 43a using the fastening bolt 47, whereby the acceleration sensor 14 is attached and fixed as a single unit to the fixing bases 41a, 42a of the acceleration detection bits 41, 42.

[0035] In addition, in this embodiment, a connection cable 48, which is wiring connected to the acceleration sensor 14, is arranged inside the mounting stand 46 via a connector 49 attached to the joining base portion 45 of the acceleration detection jig 44, and is extended through the hollow interior 43d of the cutter spoke 43 (see Figure 3) to be connected to the computer 20.

[0036] Furthermore, in this embodiment, the acceleration detection bits 41, 42 to which the acceleration sensor 14 is attached are the leading bits 16b that are fixed to the surface of the front plate 43a of the cutter spoke 43 and cut the natural ground first.

[0037] In this embodiment, the cutter head 13 to which the acceleration sensor 14 is attached has a circular front shape with a radius of, for example, approximately 6800 mm, as shown in FIG. 2. It includes a disk-shaped center drum 13b with a fishtail bit 13c attached, which is integrally joined to the center shaft 13a (see FIG. 1), and twelve cutter spokes 43 extending radially outward from the center drum 13b. The twelve cutter spokes 43 are integrally connected to each other by an annular outer support ring 13d arranged concentrically with the center drum 13b, thereby firmly supporting the rotational reaction force generated when cutting the ground 12a, 12b, and 12c. In the cutter head 13, the opening areas surrounded by each pair of adjacent cutter spokes 43, the center drum 13b, and the outer support ring 13d each form an opening 13e for taking in soil and sand. The cut soil and gravel from the ground 12a, 12b, 12c of the working face 12 cut by the multiple bits 16 attached to the cutter head 13 is taken into the rear compartment 19 through these soil intake openings 13e.

[0038] In this embodiment, the twelve cutter spokes 43 each have a hollow cross-sectional shape, for example, an isosceles trapezoidal shape, as shown in Fig. 3, and preferably have a hollow interior 43d large enough for an operator to enter. This allows an operator to perform predetermined tasks in the hollow interior 43d as needed, and also allows various wiring and piping to be installed. The hollow interior 43d of each cutter spoke 43 communicates with the interior of the center drum 13b and the center shaft 13a, and the installed wiring and piping can be extended to the rear of the partition wall 17 via, for example, a known rotary joint provided on the center shaft 13a.

[0039] Furthermore, in this embodiment, each cutter spoke 43 and outer peripheral support ring 13d has a leading bit 16b fixed to the surface of the front plate 43a, which cuts the ground before the other bits 16, as well as a plurality of known bits 16, such as a main bit, trim bit, scraper bit, copy cutter 16a, etc., which are arranged in predetermined positions and attached as a unit using a known joining method.

[0040] In this embodiment, in each cutter spoke 43, the multiple leading bits 16b fixed to the surface of the front plate 43a are arranged in two rows in a staggered pattern, connected together at a predetermined radial interval, as shown in Figure 2, and as shown in Figures 3 and 4(a) and (b), each fixing base is fixed to the front plate 43a of the cutter spoke 43 (see Figure 2) by welding or the like, and is attached in a state where it protrudes forward from the front plate 43a of the cutter spoke 43. In this embodiment, of these leading bits 16b, for example, one selected leading bit 16b arranged on one or two cutter spokes 43 on the outer periphery of the cutter head 13 is designated as the outer periphery acceleration detection bit 41, and preferably one or two selected leading bits 16b arranged in the intermediate region between the center and outer periphery of the cutter head 13 on the same cutter spoke 43 are designated as the intermediate acceleration detection bit 42, and the acceleration sensors 14 are integrally attached to each of these acceleration detection bits 41, 42 by the mounting structure 40 of this embodiment using an acceleration detection jig 44. Vibration characteristics differ for each cutter spoke 43, but by preferably arranging the outer periphery acceleration detection bit 41 and the intermediate acceleration detection bit 42 on the same cutter spoke 43, it is possible to ignore the difference in vibration characteristics. As shown by the ▽ mark in Figure 2, in this embodiment, in each of preferably two selected cutter spokes 43, one outer peripheral acceleration detection bit 41 and one intermediate acceleration detection bit 42 are provided by the leading bit 16b, with the same radial distance from the center.

[0041] Here, as the plurality of leading bits 16b, some of which become acceleration detection bits 41, 42, it is preferable to use, for example, a product name "Stamina Bit" (manufactured by Okumura Corporation), which has a configuration similar to that of the excavator cutter bit described in Design Registration No. 1533573. The leading bits 16b (acceleration detection bits 41, 42) made of "Stamina Bit" are made of tip portions 41b, 42b made of superalloy and shank portions 41c, 42c made of steel, and have the function of striking and disturbing the ground with the tip portions 41b, 42b. The acceleration detection bits 41, 42 of the preceding bit 16b are firmly attached to the cutter spoke 43 by joining, by welding or the like, the fastening bases 41a, 42a, made of steel, similar to the shanks 41c, 42c, to the front plate 43a of the cutter spoke 43 at the attachment positions of the acceleration detection bits 41, 42, where the attachment holes 43b and bolt fastening holes 43c are formed. At the attachment positions of the acceleration detection bits 41, 42, the attachment holes 43b formed in the front plate 43a of the cutter spoke 43 are circular through-holes with a diameter of, for example, approximately 30 mm. The bolt fastening holes 43c formed on the back side of the front plate 43a of the cutter spoke 43 are female threaded holes with a thread diameter of, for example, approximately 12 mm, and are preferably formed in four locations at equal angular intervals of 90° in the circumferential direction in the outer peripheral region surrounding the attachment holes 43b (see FIG. 5(b)). Furthermore, in the center of the bottom surface of the fixing bases 41a, 42a of the acceleration sensing bits 41, 42, bite holes 41d, 42d, preferably having the same inner diameter as the mounting and fixing hole 43b, are formed as openings as part of the mounting and fixing hole 43b.

[0042] The acceleration detection bits 41, 42 are fixed to the front plate 43a by welding or other welding means at their attachment positions on the front plate 43a of the cutter spoke 43 with their longitudinal directions L aligned circumferentially about the center of the cutter head 13 (see FIG. 2) and with the bite holes 41d, 42d of the attachment bases 41a, 42a aligned with the attachment holes 43b of the front plate 43a. As a result, when the acceleration detection bits 41, 42 are attached to the front plate 43a of the cutter spoke 43, the attachment holes 43b, into which the attachment erection portions 46 of the acceleration detection jig 44 are inserted and fixed, are formed to a depth reaching the bite holes 41d, 42d in the attachment bases 41a, 42a of the acceleration detection bits 41, 42.

[0043] 4(a) to 4(c) and 5(a) to 5(d), the acceleration sensor 14 is housed in the inner tip portion of an acceleration detection jig 44, which is made up of a metal joint base portion 45 and a mounting stand portion 46, and is fixed and attached as a unit to the acceleration detection bits 41, 42 via the acceleration detection jig 44. The acceleration detection jig 44 is preferably a metal piece made of steel, and the joint base portion 45 has a disk shape with a diameter of, for example, about 100 mm and a thickness of, for example, about 16 mm. In addition, a circular fitting hole 45b is formed through the central part of the joining base part 45, into which the erected base end part 46a of the erected mounting part 46 is fitted and fixed, and in the outer peripheral region surrounding this fitting hole 45b and the erected base end part 46a of the erected mounting part 46 fitted therein, the above-mentioned bolt insertion holes 45a are formed in four places, preferably at equal angular intervals of 90° in the circumferential direction (see Figure 5(b)).

[0044] On the other hand, the mounting upright portion 46 of the acceleration detecting jig 44 is configured to include a cylindrical upright base end portion 46a and a tip-side notched cross-sectional portion 46b, which is located tip-side of the upright base end portion 46a and has a cross-sectional shape in which the side of the circular cross section is notched in an arch-like shape. The mounting upright portion 46 is joined to the joining base portion 45 by adhesive or welding, with the base-side portion of the upright base end portion 46a fitted into the fitting hole 45a of the joining base portion 45, so that the tip-side portion of the upright base end portion 46a and the tip-side notched cross-sectional portion 46b are erected perpendicularly from the joining base portion 45, and the mounting upright portion 46 is integrated with the joining base portion 45 to form the acceleration detecting jig 44.

[0045] A connector connection hole 46c, for example, having a female thread ridge, is formed in a base end portion of the standing base end portion 46a fitted into the joint base portion 45 of the standing mounting portion 46. The connector connection hole 46c is for connecting a connector 49 that draws a connection cable 48 extending through the hollow interior 43d of the cutter spoke 43 into the acceleration detection jig 44. A wiring insertion hole 46e (see FIG. 5(d)), for example, having a semi-oval cross section, is formed in the tip end portion of the standing base end portion 46a protruding from the joint base portion 45, on the opposite side of the connector connection hole 46c across the bridge member 46d. A wiring routing groove 46f (see FIG. 5(c)), for example, having a semi-oval cross section, is formed in the cutout surface of the tip end side cutout cross-sectional shape portion 46b of the standing mounting portion 46, except for the tip end portion. The wiring routing groove 46f (see FIG. 5(c)) is continuous with the wiring insertion hole 46e of the standing base end portion 46a. At the tip end portion of the wiring arrangement groove 46f of the tip end cutout cross-sectional shape portion 46b, a sensor mounting portion 46g having a rectangular hollow cross-sectional shape is formed, which can accommodate the acceleration sensor 14, which preferably has a hexahedral shape, in a state where it is positioned so that it cannot rotate.

[0046] Furthermore, in the central part of the arch-shaped cutout surface in the tip-side cutout cross-sectional portion 46b of the mounting upright portion 46, the band-shaped opening surface of the above-mentioned wiring arrangement groove 46f extends in the upright direction and opens, and on both sides of the wiring arrangement groove 46f, screw holes 46h with a screw diameter of, for example, about 2 mm are formed in a total of six places, for example, three places on each side, at a predetermined interval in the upright direction. For example, by working inside the hollow interior 43d of the cutter spoke 43, the connection cable 48 arranged inside the hollow interior 43d is pulled into the wiring insertion hole 46e and wiring arrangement groove 46f via the connector 49 and the link member 46d (see FIGS. 4(a) and 4(b)), and the acceleration sensor 14 is attached to the tip of the connection cable 48. After that, with the connection cable 48 and the acceleration sensor 14 housed in the wiring arrangement groove 46f and the sensor mounting portion 46g, a cover plate 46i (see FIGS. 5(b) and 5(c)) is attached so as to cover the band-shaped opening surface of the wiring arrangement groove 46f by screwing fixing screws 46j into the screw holes 46h on both sides of the wiring arrangement groove 46f. This makes it possible to precisely and stably position the acceleration sensor 14, which is connected to the computer 20 via the connection cable 48, at the tip of the mounting stand 46, and then house and fix it as a single unit inside the acceleration detection jig 44, which consists of a metal joint base part 45 and the mounting stand 46 that stands up from the joint base part 45.

[0047] In this embodiment, the connection cable 48 and acceleration sensor 14 connected to the computer 20 are placed in the wiring insertion hole 46e in the upright end portion 46a and the wiring routing groove 46f in the tip-side notched cross-sectional portion 46b formed inside the upright mounting portion 46 as described above, and the band-shaped opening of the wiring routing groove 46f is then covered with the cover plate 46i. By filling the wiring insertion hole 46e and the wiring routing groove 46f with a filling and hardening agent and hardening it, it is possible to eliminate gaps around the connection cable 48 and the acceleration sensor 14. By filling the inside of the upright mounting portion 46 with a filling and hardening agent in this manner, the acceleration sensor 14 and the connection cable 48 can be accurately positioned and fixed inside the acceleration detection jig 44 in a more stable state.

[0048] In this embodiment, the acceleration sensor 14 is, for example, a triaxial piezoelectric acceleration detector, and is preferably capable of detecting cutting vibration data in three directions, i.e., at least two directions perpendicular to each other. The acceleration sensor 14 has a hexahedral shape with six faces arranged at right angles to each other, as shown in Figures 6(a) to 6(d), for example, and is capable of detecting cutting vibration data in each of the three directions, i.e., the X, Y, and Z directions perpendicular to each face. Furthermore, the acceleration sensor 14 is accommodated in a sensor mounting portion 46g having a rectangular hollow cross-sectional shape at the tip of the wiring arrangement groove 46f formed in the cutout cross-sectional portion 46b of the acceleration detection jig 44, and is thereby positioned and fixed so that, for example, the Z direction faces a direction perpendicular to the erection direction of the mounting erection portion 46 along the cutout surface of the cutout cross-sectional portion 46b, the X direction faces the erection direction of the mounting erection portion 46 along the cutout surface of the cutout cross-sectional portion 46b, and the Y direction faces a direction perpendicular to the cutout surface of the cutout cross-sectional portion 46b.

[0049] In addition, in this embodiment, the four bolt insertion holes 45a formed in the outer peripheral region surrounding the fitting hole 45b in the central part of the joint base portion 45 and the erection base end portion 46a of the mounting erection portion 46 fitted thereto are formed such that, as shown in Figure 5(b), one pair of bolt insertion holes 45a are formed so as to be positioned on both sides of the fitting hole 45a and the erection base end portion 46a of the mounting erection portion 46 in a plane parallel to the cutout surface of the cutout cross-sectional shape portion 46b, and the other pair of bolt insertion holes 45a are formed so as to be positioned on both sides of the fitting hole 45b and the erection base end portion 46a of the mounting erection portion 46 in a plane perpendicular to the cutout surface of the cutout cross-sectional shape portion 46b.

[0050] On the other hand, at the mounting position of the acceleration detection bits 41, 42 on the front panel 43a of the cutter spoke 43, four bolt fastening holes 43c are formed in the outer peripheral region of the mounting fixing hole 43b into which the mounting erection portion 46 of the acceleration detection jig 44 is inserted and fixed.One pair of bolt fastening holes 43c are formed so that they are positioned on both sides of the mounting fixing hole 43b in a plane perpendicular to the longitudinal direction L of the acceleration detection bits 41, 42, and the other pair of bolt fastening holes 43c are formed so that they are positioned on both sides of the mounting fixing hole 43b in a plane parallel to the longitudinal direction L of the acceleration detection bits 41, 42.

[0051] As a result, according to this embodiment, when the leading bit 16b including the acceleration detection bits 41, 42 is attached to the cutter spokes 43 that constitute the cutter head 13, and the front plate 43a at the attachment position of the acceleration detection bits 41, 42 has the attachment fixing hole 43b and the bolt fastening hole 43c formed therein, the above-mentioned acceleration detection jig 44, in which the acceleration sensor 14 is housed in the inner tip portion of the attachment standing portion 46, is inserted and attached to the attachment fixing hole 43b to a depth where the tip reaches the bite holes 41d, 42d, and the joining base portion 45 is fastened to the front plate 43a of the cutter spoke 43 from the back side using the fastening bolt 47, and fixed to the front plate 43a, this work can be easily and smoothly performed by a worker working in the hollow interior 43d of the cutter spoke 43, preferably large enough for the worker to enter. This also makes it possible to easily and smoothly attach and fix the acceleration sensor 14 as a single unit to each of the acceleration detection bits 41, 42, preferably with the Z direction as the first detection direction, aligned along the longitudinal direction L of the acceleration detection bits 41, 42, which is the rotation direction of the cutter head 13, and preferably with the X direction as the second detection direction, aligned along the protruding direction of the acceleration detection bits 41, 42, which is perpendicular to the front panel 43a of the cutter spokes 43 that constitute the head surface of the cutter head 13, which is the excavation direction of the cutter head 13.

[0052] In other words, the acceleration detection jig 44 is a detection jig that, in a sealed shield tunneling machine that has a rotating cutter head 13 at the tip of the shield body 15 and excavates while cutting the face using multiple bits 16 attached to the cutter head 13, fixes the acceleration sensor 14 as a single unit to the acceleration detection bits 41, 42 attached to the front panel 43a of the cutter spokes 43 that make up the cutter head 13 by working from the back side of the front panel 43a, thereby enabling the vibration acceleration of the acceleration detection bits 41, 42 during cutting to be detected with high accuracy. The acceleration detection jig 44 has a joining base portion 45 and an attachment upright portion 46 that stands up integrally from the joining base portion 45, and is used by inserting and fixing the attachment upright portion 46 into an attachment fixing hole 43b that is formed at the attachment position of the acceleration detection bits 41, 42 on the front plate 43a of the cutter spokes 43 that make up the cutter head 13, the attachment fixing hole 43b having penetrated the front plate 43a to a depth that penetrates into the fixing bases 41a, 42a of the acceleration detection bits 41, 42, and with the joining base portion 45 joined to the back surface of the front plate 43a. For example, when the bolt insertion hole 45a and the fastening bolt 47 are used as positioning and joining means and the circumferential position of the rear surface of the front panel 43a is positioned around the mounting fixing hole 43b of the joining base portion 45 by the positioning and joining means of these bolt insertion hole 45a and fastening bolt 47, the orientation of the acceleration sensor 14 relative to the positioning and joining means (bolt insertion hole) 45a of the joining base portion 45 is adjusted by, for example, the hexahedral acceleration sensor 14 and the sensor mounting portion 46g having a rectangular hollow cross-section so that the Z direction, which is one detection direction (first detection direction) of cutting vibration data by the acceleration sensor 14 housed in the inner tip portion of the mounting stand 46, coincides with the circumferential direction when the acceleration detection bits 41, 42 rotate and move in accordance with the rotation of the cutter head 13, and the acceleration sensor 14 is fixed to the inner tip portion of the mounting stand 46.

[0053] Therefore, according to the acceleration sensor mounting structure 40 in the shield tunneling machine of this embodiment, by using the acceleration detection jig 44, it is possible to easily and smoothly fix the acceleration sensor 14 as a single unit to the acceleration detection bits 41, 42 attached to the front plate 43a of the cutter spokes 43 that make up the cutter head 13 through simple work from the back side of the front plate 43a, without causing any problems due to heat or electricity caused by welding, etc.

[0054] Furthermore, in the acceleration detection jig 44, as described above, the positioning joining means is preferably configured to include bolt insertion holes 45a formed in at least two locations in the outer peripheral region surrounding the mounting upright portion 46 of the joining base portion 45 so as to match with bolt fastening holes 43c formed in at least two locations in the outer peripheral region surrounding the mounting fixing hole 43b at the mounting position of the acceleration detection bits 41, 42 on the front panel 43a of the cutter spokes 43 that constitute the cutter head 13, and fastening bolts 47 that are inserted and fastened into these matched bolt fastening holes 43c and bolt insertion holes 45a.

[0055] Furthermore, in the acceleration detection jig 44, as described above, the acceleration sensor 14 preferably has a hexahedral shape and is attached by being fitted into a sensor mounting portion 46g having a rectangular hollow cross-sectional shape formed at the inner tip portion of the mounting stand 46, so that its circumferential position on the mounting stand 46 is fixed.

[0056] Furthermore, in the acceleration detection jig 44, as described above, a pair of bolt insertion holes 45a are formed on both sides of the mounting stand 46, preferably on a virtual plane parallel to a predetermined side of the hexahedral acceleration sensor mounted by being fitted into the sensor mounting portion 46g (for example, a plane parallel to the plane along CC in FIG. 5).

[0057] Furthermore, in this embodiment, the mounting portion 46 of the acceleration detection jig 44 is preferably adapted to be inserted into the mounting hole with an adhesive applied or filled over the entire outer circumferential surface of the mounting portion 46. This allows the acceleration sensor 14 to be precisely positioned on the acceleration detection bits 41, 42 in a more stable state, preferably with the Z direction aligned with the longitudinal direction L of the acceleration detection bits 41, 42, which is the rotation direction of the cutter head 13, and firmly fixed as a single unit.

[0058] As a result, with the acceleration detection jig 44, the mounting erection portion 46 is inserted and attached, for example, into the mounting fixing hole 43b from the back side of the front plate 43a of the cutter spokes 43 that make up the cutter head 13, and the bolt insertion hole 45a is aligned with the bolt fastening hole 43c, and the joining base portion 45 is overlapped with the front plate 43a from the back side, and then fastened and fixed to the front plate 43a using the fastening bolt 47.This simple procedure makes it possible to easily and smoothly fix the acceleration sensor 14 as a single unit to the acceleration detection bits 41, 42 attached to the front plate 43a, for example, with one of its detection directions Z positioned as a predetermined direction in the acceleration detection bits 41, 42, preferably in a direction along the circumferential rotational trajectory along which these acceleration detection bits 41, 42 rotate.

[0059] Furthermore, in this embodiment, the acceleration sensor 14 is first housed in a fixed state inside the acceleration detection jig 44, and then attached as a unit to the acceleration detection bits 41, 42 via the acceleration detection jig 44 from the back side of the front plate 43a of the cutter spokes 43 that make up the cutter head 13. This eliminates the need to weld the acceleration detection jig 44 and the cutter head 13 when installing the acceleration sensor 14 inside the bit, reducing the risk of damaging the acceleration sensor 14 due to heat or electricity generated during welding. Furthermore, because the acceleration sensor 14 is first housed in a fixed state inside the acceleration detection jig 44 and then firmly attached as a unit to the acceleration detection bits 41, 42, it is possible to effectively reduce the risk of malfunctioning of the acceleration sensor 14 due to the intrusion of groundwater or the like during excavation.

[0060] If it is difficult to ensure sufficient space for an operator to enter the hollow interior 43d of the cutter spoke 43, for example, an openable access window (not shown) can be provided in the rear plate 43e (see FIG. 3) of the cutter spoke 43, preferably in an area corresponding to the portion where the acceleration detection bits 41 and 42 are attached, of the rear plate 43e. With the leading bit 16b including the acceleration detection bits 41 and 42 attached to the cutter head 13 and the attachment holes 43b and bolt fastening holes 43c formed at the attachment positions of the acceleration detection bits 41 and 42, the acceleration detection jig 44, with the acceleration sensor 14 housed in the inner tip of the attachment portion 46, can be smoothly inserted and attached through the openable access window to the attachment hole 43b to a depth reaching the bite holes 41d and 42d, and the joining base portion 45 can be fastened and fixed to the front plate 43a of the cutter spoke 43 from the back side using the fastening bolts 47.

[0061] In addition, in this embodiment, the acceleration sensor 14 is preferably arranged in the longitudinal direction L of the acceleration detection bits 41, 42, which is a direction along the circumferential direction of rotation of the cutter head 13, with the Z direction as the first detection direction, and the X direction as the second detection direction, which is a direction along the excavation direction perpendicular to the head surface of the cutter head 13.This makes it possible to efficiently measure the ground response acceleration in the circumferential direction of rotation using the first detection direction Z, and the ground response acceleration in the excavation direction using the second detection direction X, and it becomes possible to obtain even more accurate concentric circular cutting vibration distributions 23a, 23b (see Figure 7) from the response acceleration detected by these outer peripheral acceleration detection bit 41 and middle acceleration detection bit 42.

[0062] In this embodiment, as shown in FIG. 1, auxiliary acceleration sensor 18 is attached to the back surface of partition wall 17, which separates compartment 19, as the inner wall surface of shield body 15. Like acceleration sensor 14, auxiliary acceleration sensor 18 is a three-axis piezoelectric acceleration detector, and is preferably attached to the back surface of partition wall 17 with its first detection direction aligned with the circumferential direction of rotation of cutter head 13 and its second detection direction aligned with the excavation direction of shield machine 11. This makes it possible to efficiently and accurately measure and obtain specific vibration data caused by vibration of shield body 15 during operation of shield machine 11. Auxiliary acceleration sensor 18 is also connected to acceleration sensor amplifier 25b via a connection cable. The main body vibration data from the auxiliary acceleration sensor 18 is sent to the computer 20 via the acceleration sensor amplifier 25b and the transmission system 29, and the vibration data display unit 22 is able to display the cutting vibration data for each rotation angle sent from the acceleration sensor 14 as multiple concentric ring-shaped cutting vibration distributions 23a, 23b, with noise and mechanical vibrations removed.

[0063] Furthermore, in this embodiment, a tachometer (not shown) consisting of, for example, a rotary encoder is attached to the center shaft 13a of the cutter head 13. The rotation angle measured by this tachometer is sent to the computer 20 via the transmission system 29, and cutting vibration data measured by the acceleration sensor 14 when cutting the working face 12 can be stored in the vibration data storage unit 21 for each predetermined rotation angle.

[0064] According to this embodiment, the frequency Δθ of circumferential measurements by acceleration sensor 14 is determined by the formula Δθ = r / 60 × Δt × 360°, using the data collection time interval Δt and the rotational speed r (ppm) of cutter head 13. For example, if shield machine 11 is a small-diameter machine with an excavation outer diameter of approximately 2360 mm and has a fast rotational speed r = 2.3 (ppm), the measurement frequency Δθ when the measurement time interval Δt is set to 0.1 seconds is Δθ = 2.3 / 60 × 0.1 × 360°, which is 1.38°. Therefore, acceleration sensor 14 will take a measurement every 1.38°.

[0065] In addition, in this embodiment, in order to grasp the circumferential position θ° of the acceleration sensor 14 in the cutter head 13, a contact switch (not shown) is installed on the center shaft 13a of the cutter head 13, and for example, the top of the shield tunneling machine 11 can be set as the zero point, and a reset process can be performed every time this zero point is passed.

[0066] In this embodiment, the cutting vibration data measured by the acceleration sensor 14 at each predetermined rotation angle is output via dedicated acceleration sensor amplifiers 25a, 25b, together with the main body vibration data measured by the auxiliary acceleration sensor 18, preferably at the same timing as the measurement by the acceleration sensor 14, and the output signal passes through the control panel 26 and sequencer panel 27 and is sent to the operation control room 30 via the same transmission system 29 as other excavation management data.

[0067] In this embodiment, the computer 20 constituting the system 10 for determining face soil type distribution using a shield machine is configured to include, as described above, a vibration data storage unit 21 and a vibration data display unit 22. The vibration data storage unit 21 stores cutting vibration data, which is sent from the acceleration sensor 14 to the computer 20 via the acceleration sensor amplifier 25a and the transmission system 29 when the face 12 is cut by the cutter bit 16, for each predetermined rotation angle of the cutter head 13. The vibration data storage unit 21 also stores main body vibration data, which is sent from the auxiliary acceleration sensor 18 to the computer 20 via the acceleration sensor amplifier 25b and the transmission system 29 when the face 12 is cut by the cutter bit 16 and is caused by the shield main body 15 itself vibrating due to drive of the rotation drive motor or the like, for each predetermined rotation angle of the cutter head 13. These cutting vibration data and main body vibration data can be integrated in a known shield tunneling management system built into computer 20 in a chronological order with measurement values collected from various measuring instruments used in the shield tunneling method, and stored as data linked to the ring number of each ring, preferably assembled using segments.

[0068] The vibration data display unit 22 displays the cutting vibration data for each rotation angle stored in the vibration data storage unit 21 as a plurality of concentric ring-shaped cutting vibration distributions 23a, 23b distributed in the circumferential direction of a circle that imitates the cutting face cross section. That is, as shown in Fig. 7, the vibration data display unit 22 is capable of displaying, as cutting vibration data for each rotation angle, preferably a distribution of magnitude of vibration acceleration (ground response acceleration during cutting) for each rotation angle, as a plurality of concentric ring-shaped cutting vibration distributions 23a, 23b on, for example, a display 20a connected to the computer 20, with noise and mechanical vibrations removed using main body vibration data sent from the auxiliary acceleration sensor 18.

[0069] The computer 20 also includes a boundary line display unit 31 (see FIG. 1) that enables the boundary portions of different soil types in the ground 12a, 12b, 12c of the working face 12 to be distinguished from the fluctuation points 24a, 24b of the distribution wave state in the circumferential cutting vibration distributions 23a, 23b displayed by the vibration data display unit 22. The boundary line display unit 31 is preferably configured to display, as shown in FIG. 7, a polygonal connecting line 50 that sequentially connects the fluctuation points 24a, 24b, 24b, 24a of the wave state of each adjacent pair of distributions in the multiple concentric annular cutting vibration distributions 23a, 23b displayed by the vibration data display unit 22, as the boundary portions of different soil types in the ground of the working face. The boundary line display unit 31 can also display a straight connecting line 51 connecting the midpoints of each pair of adjacent fluctuation points 24a, 24b on both sides in the multiple concentric circular cutting vibration distributions 23a, 23b displayed by the vibration data display unit 22 as the boundary between different soil types in the ground at the cutting face.

[0070] 7 are displayed on the display 20a after noise and mechanical vibrations have been removed using main body vibration data from the auxiliary acceleration sensor 18 in the first detection direction, preferably the circumferential direction of the cutter head 13. The cutting vibration distributions 23a and 23b shown in Fig. 7 are obtained by detecting the cutting vibration data from the acceleration sensors 14 attached to the outer periphery acceleration detection bit 41 and the middle acceleration detection bit 42 in the Z direction, which is preferably the circumferential direction of the cutter head 13. This makes it possible to display cutting vibration distributions 23a and 23b that more accurately reflect the condition of the ground 12a, 12b, and 12c on the working face 12 being cut by the cutter head 13.

[0071] Furthermore, the cutting vibration data of the cutting vibration distributions 23a and 23b shown in Figure 7 can be based on the data obtained as the average of the measurement values for five rotations by starting measurement for each ring of excavation span of the segments that make up the shield tunnel, for example, when the jack stroke of the shield jack or the propulsion jack has advanced 100 mm from the start of excavation of the excavation span for one ring, and continuing to measure cutting vibration data while the cutter head 13 rotates five times.

[0072] 7 are obtained by the outer periphery acceleration detection bit 41 and the middle acceleration detection bit 42 attached to one of two selected cutter spokes 43, each of which is provided with an outer periphery acceleration detection bit 41 and a middle acceleration detection bit 42. The accuracy of the cutting vibration distributions 23a and 23b can be confirmed by obtaining similar cutting vibration distributions 23a and 23b based on the cutting vibration data from the outer periphery acceleration detection bit 41 and the middle acceleration detection bit 42 attached to the other cutter spoke 43. Preferably, similar cutting vibration distributions 23a and 23b can also be obtained from the average value of the cutting vibration data from the outer periphery acceleration detection bit 41 and the middle acceleration detection bit 42 of each of the two cutter spokes 43.

[0073] Furthermore, the above-described system for determining soil type distribution at the tunnel face using a shield machine makes it possible to easily identify the boundary between different soil types in the ground 12a, 12b, and 12c at the tunnel face 12 from the multiple concentric circular cutting vibration distributions 23a and 23b displayed by the vibration data display unit 22 as shown in Figure 7. That is, in this embodiment, by observing the multiple concentric circumferential cutting vibration distributions 23a and 23b displayed, it is possible to easily identify vibration fluctuation points 24a and 24b, which are points where the vibration distribution trend clearly changes. In the cutting vibration distributions 23a and 23b in Figure 7, vibration fluctuation points 24a and 24b can be identified, one on each side. Furthermore, by drawing the broken line connecting line 50 or the straight line connecting line 51 using the above-mentioned method based on the fluctuation points 24a, 24b on both the left and right sides, the layer structure of the ground 12a, 12b, 12c on the working face 12 can be determined, and preferably by referring to a columnar diagram of the surrounding ground, it becomes possible to easily determine the soil quality of each layer of the determined layer structure.

[0074] In addition, the face soil quality distribution discrimination system is equipped with a boundary line display unit 31 that displays the connection lines 50, 51 connecting each pair of vibration fluctuation points 24a, 24b on both the left and right sides as the boundary parts of different soil types in the ground 12a, 12b, 12c of the face 12.By displaying the connection lines 50, 51 using this boundary line display unit 31, it becomes possible to more easily grasp the boundary parts of different soil types on the face 12 and the layer structure of the ground 12a, 12b, 12c.

[0075] The present invention is not limited to the above-described embodiment and various modifications are possible. For example, the acceleration sensor does not necessarily have to have a hexahedral shape; its circumferential position on the mounting stand may be fixed by a method other than being fitted into a sensor mounting portion having a rectangular hollow cross-section. While the present embodiment describes a spoke-type cutter head, the present invention can also be applied to a face plate-type cutter head. In a face plate-type cutter head, the cutter spokes correspond to the main frame of the cutter face plate. Furthermore, if it becomes necessary to replace the bit during excavation work, as in the above-described embodiment, the bit can be first attached to the front plate of the cutter spoke by welding or the like, and then the mounting stand of the detection jig containing the acceleration sensor can be attached to the mounting hole of the front plate and the base portion can be fixed to the front plate with a fixing bolt. This allows the acceleration sensor to be attached using the acceleration sensor mounting structure of the present invention. [Explanation of symbols]

[0076] 10. System for determining soil distribution at the tunnel face using a shield machine 11 Shield tunneling machine 12 Face 12a, 12b, 12c Ground at the face 13 Cutter head 13a Center shaft 13b center drum 13c fishtail bit 13d Periphery support ring 13e Opening for sediment intake 14 Accelerometer 15 Shield body 16-bit 16a Copy cutter 16b leading bit 17 Bulkhead 18 Auxiliary Accelerometer 19 compartment 20 Computer 21 Vibration data storage unit 22 Vibration data display 23a, 23b Circumferential cutting vibration distribution 24a, 24b Locations where the distribution wave state changes 29 Transmission Systems 30 Operation Control Room 31 Boundary line display area 40 Acceleration sensor mounting structure 41 Periphery acceleration detection bit 42 Intermediate acceleration detection bit 41a, 42a Fixation base 41d,42d Biting hole 43 Cutter Spoke 43a Front plate 43b Mounting and fixing hole 43c Bolt fastening hole 43d hollow interior 43e back plate 44 Acceleration detection jig 45 Joint base part 45a Bolt insertion hole 45b Fitting hole 46 Mounting section 46a Standing base end part 46b Tip side notch cross-sectional shape part 46c Connector connection hole 46d. Link material 46e Wiring insertion hole 46f Wiring groove 46g Sensor mounting part 46h screw hole 46i Lid Plate 46j fixing screw 47 Fastening bolt 48 Connection Cable 49 Connectors 50 foldable bond lines 51 Straight bond lines

Claims

1. In a shield tunneling machine equipped with a face soil distribution determination system including an acceleration sensor attached to a cutter head and a computer connected to the acceleration sensor, an acceleration sensor mounting structure for a shield tunneling machine for integrally mounting and fixing the acceleration sensor to a bit disposed on the cutter head, an acceleration detection bit to which the acceleration sensor is attached is fixed to a front plate of a cutter spoke constituting the cutter head in a state of protruding forward from the front plate; The acceleration sensor is housed in a fixed state inside an acceleration detection jig consisting of a metal joint base portion and a mounting portion standing upright from the joint base portion, and is attached to the acceleration detection bit via the acceleration detection jig as a single unit, The front plate of the cutter spoke is formed at the mounting position of the acceleration detection bit with a mounting fixing hole into which the mounting erection portion of the acceleration detection jig is inserted and fixed, the mounting fixing hole penetrating to a depth reaching a fixing base of the acceleration detection bit, and bolt fastening holes are formed on both sides of the mounting fixing hole on the back side, The joining base portion of the acceleration detection jig has bolt insertion holes formed on both sides of the mounting stand portion, An acceleration sensor mounting structure for a shield tunneling machine in which the mounting erection portion is inserted and mounted into the mounting fixing hole, the bolt insertion hole is aligned with the bolt fastening hole, the joining base portion is superimposed on the front plate, and then the acceleration detection jig is fastened and fixed to the front plate using a fastening bolt, thereby mounting and fixing the acceleration sensor to the acceleration detection bit as a single unit.

2. 2. An acceleration sensor mounting structure for a shield tunneling machine as described in claim 1, wherein wiring connected to the acceleration sensor is routed inside the mounting upright portion via a connector provided on the joint base portion of the acceleration detection jig, and is extended through the hollow interior of the cutter spoke to be connected to the computer.

3. 3. The mounting structure for an acceleration sensor in a shield tunneling machine according to claim 1, wherein the interior of the mounting upright portion of the acceleration detection jig in which the acceleration sensor is housed is filled with a filling and solidifying agent.

4. 3. The mounting structure for an acceleration sensor in a shield tunneling machine according to claim 1, wherein the mounting erection portion of the acceleration detection jig is inserted and mounted in the mounting fixing hole with an adhesive applied to its outer circumferential surface.

5. A method for constructing the acceleration sensor mounting structure in the shield tunneling machine according to claim 1 or 2, comprising: The bit is disposed on the cutter head, and the mounting fixing hole and the bolt fastening hole are formed at the mounting position of the acceleration detection bit, A method for installing an acceleration sensor in a shield tunneling machine, in which the acceleration sensor is fixedly housed inside the mounting stand, and the acceleration detection jig is fastened to the front panel using a fastening bolt, thereby attaching and fixing the acceleration sensor to the acceleration detection bit as a single unit.

6. The cutter spoke has a hollow cross-sectional shape that allows an operator to enter, 6. A method for attaching an acceleration sensor to a shield machine according to claim 5, wherein an operator enters the interior of the cutter spoke and attaches and fixes the acceleration sensor to the acceleration detection bit as a single unit.

7. An openable and closable work window is provided on the back panel of the cutter spoke, 6. A method for attaching an acceleration sensor to a shield machine according to claim 5, wherein the acceleration sensor is attached and fixed integrally to the acceleration detection bit by work through the work window.

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