Patent Publication Number: US-2022220849-A1

Title: Tunnel boring machine, measurement method, and measurement system

Description:
FIELD 
     The present invention relates to a tunnel boring machine, a measurement method, and a measurement system. 
     BACKGROUND 
     Regarding a tunnel boring machine, the wear amount of a disc cutter mounted on a cutterhead is measured regularly. Known has been a technique of showing the condition of the leading end portion of a tunnel boring machine on an image display device by use of an image sensor (for example, refer to Patent Literature 1). As a technique of measuring the shape of an object in a noncontact manner, known has been a three-dimensional shape measurement device. 
     CITATION LIST 
     Patent Literature 
     
         
         Patent Literature 1: JP H04-110642 A 
       
    
     SUMMARY 
     Technical Problem 
     In a case where the wear amount of a disc cutter is measured with a three-dimensional shape measurement device, for example, three-dimensional data of the disc cutter in the criterial state, such as just after attachment or before operation, and three-dimensional data of the disc cutter in an operation state are superimposed together on the basis of features of the shape of the disc cutter, and then the wear amount is measured. However, a change in the shape of the disc cutter due to wearing is likely to cause a larger error in superimposition of such pieces of three-dimensional data. 
     An object of the present invention is to achieve highly accurate measurement of the wear amount of a disc cutter. 
     Solution to Problem 
     According to an aspect of the present invention, a tunnel boring machine comprises: a disc cutter including a cutter ring; and a member for use in measurement of a wear amount of the cutter ring with a three-dimensional shape measurement device, wherein the member is provided at a part constant in relative position to the cutter ring. 
     Advantageous Effects of Invention 
     According to the present invention, highly accurate measurement of the wear amount of a disc cutter can be achieved. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a side view of the configuration of a tunnel boring machine according to the present embodiment. 
         FIG. 2  is a schematic perspective view of a cutterhead of the tunnel boring machine according to the present embodiment. 
         FIG. 3  is a side view of a disc cutter mounted on a case. 
         FIG. 4  is a front view of the disc cutter mounted on the case. 
         FIG. 5  is a schematic explanatory view of detachment of the disc cutter. 
         FIG. 6  is a schematic view of the configuration of a measurement device. 
         FIG. 7  is a schematic explanatory view of a state where the measurement device measures a disc cutter. 
         FIG. 8  is a block diagram of the configuration of a controller. 
         FIG. 9  is a block diagram of a computer system according to the present embodiment. 
         FIG. 10  is a front view of members each provided at a key block by welding, in a first embodiment of the present invention. 
         FIG. 11  is a side view of a case on which a disc cutter is mounted with the key blocks each provided with the member, in the first embodiment of the present invention. 
         FIG. 12  is a front view of an exemplary member. 
         FIG. 13  is a side view of the member illustrated in  FIG. 12 . 
         FIG. 14  is a plan view of the member illustrated in  FIG. 12 . 
         FIG. 15  is a flowchart of an exemplary processing procedure of a method of measuring the cutter ring of a disc cutter in the criterial state. 
         FIG. 16  is a flowchart of an exemplary processing procedure of a method of measuring the cutter ring of a disc cutter in an operation state. 
         FIG. 17  is a schematic explanatory view of alignment in measurement. 
         FIG. 18  is a front view of an exemplary member. 
         FIG. 19  is a side view of the member illustrated in  FIG. 18 . 
         FIG. 20  is a plan view of the member illustrated in  FIG. 18 . 
         FIG. 21  is a front view of an exemplary member. 
         FIG. 22  is a side view of the member illustrated in  FIG. 21 . 
         FIG. 23  is a plan view of the member illustrated in  FIG. 21 . 
         FIG. 24  is an explanatory graph of differences in the accuracy of measurement from a conventional technique. 
         FIG. 25  is an explanatory graph of influence on the accuracy of measurement due to the angle of measurement. 
         FIG. 26  is an explanatory graph of influence on the accuracy of measurement due to the angle of measurement. 
         FIG. 27  is a schematic explanatory view of alignment with the conventional technique. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments of the present invention will be described below with reference to the accompanying drawings. However, the present invention is not limited to the embodiments. The constituent elements in the following embodiments can be appropriately combined. In some cases, some of the constituent elements are not necessarily used. 
     [Tunnel Boring Machine] 
       FIG. 1  is a side view of the configuration of a tunnel boring machine  1  according to the present embodiment.  FIG. 2  is a schematic perspective view of a cutterhead  30  of the tunnel boring machine  1  according to the present embodiment. For example, the tunnel boring machine  1  excavates rock in construction of an underground structure, such as a tunnel or a system for supplying water. The tunnel boring machine  1  includes a main body  10  and the cutterhead  30  that is provided on the front side of the main body  10  and excavates rock. As illustrated in  FIGS. 1 and 2 , the cutterhead  30  is domed in shape and internally has a cutter chamber  30 C serving as a space for taking in excavated muck generated due to excavation. 
     The main body  10  includes a main beam  14  extending in the front-and-back direction and a cutterhead support  22  provided at the front end of the main beam  14 . The cutterhead  30  is coupled rotatably to the cutterhead support  22  through a bearing  23 . The cutterhead support  22  of the main body  10  has an upper portion provided with a roof support  11 , side portions each provided with a side support  12 , and a lower portion provided with a vertical support  13 . As illustrated in  FIG. 2 , the roof support  11 , the side supports  12 , and the vertical support  13  are provided in a cylindrical shape such that the respective outer circumferences thereof are along the sectional shape for excavation. 
     Inside the main body  10 , provided are a gripper  15  to be pressed against the wall of a tunnel and a thrust jack  16  variable in length along the main beam  14 . The end portion on the front side in the axial direction of the thrust jack  16  is attached on the front side of the main beam  14  and the end portion on the back side thereof is attached to the gripper  15 . The thrust jack  16  is provided variably in length in the front-and-back direction. The tunnel boring machine  1  generates a thrust force with a variation in the length of the thrust jack  16 . The tunnel boring machine  1  presses the gripper  15  against the wall of the tunnel, to acquire a thrust reaction force. 
     Inside the main body  10 , provided are a belt conveyor  20  extending in the front-and-back direction, a chute hopper  21  provided at the upper portion on the front side of the belt conveyor  20 , the cutterhead support  22  provided at the end portion on the front side of the main beam  14 , and a drive motor  29 . The belt conveyor  20  conveys excavated muck generated due to excavation, backward. The belt conveyor  20  is provided inside the main beam  14  tubular in shape and penetrates through the cutterhead support  22  such that the leading end thereof is located in the cutter chamber  30 C. The chute hopper  21  is open in the cutter chamber  30 C and guides, to the belt conveyor  20 , excavated muck scooped in by buckets  39  of the cutterhead  30 . The cutterhead support  22  supports the cutterhead  30  rotatably around the rotation axis AX 1  thereof. The cutterhead support  22  is provided with the drive motor  29  for rotating the cutterhead  30 . The drive motor  29  serves as a hydraulic motor or an electric motor. 
     The cutterhead support  22  to which the cutterhead  30  is connected through the bearing  23  is provided with the drive motor  29 . The cutterhead  30  rotates around the rotation axis AX 1  due to the drive motor  29 . Due to a variation in the length of the thrust jack  16 , the cutterhead  30  moves in the front-and-back direction with respect to the gripper  15 . The cutterhead  30  has a plurality of disc cutters  40  mounted thereon. The cutterhead  30  is provided ahead of the main body  10 . The cutterhead  30  is provided with a plurality of cylindrical cases  32  each housing and retaining a disc cutter  40 . That is, the cases  32  provided at the cutterhead  30  are identical in position to the disc cutters  40  provided at the cutterhead  30 . 
     [Disc Cutter] 
     A disc cutter  40  will be described with  FIGS. 3 and 4 .  FIG. 3  is a side view of the disc cutter  40 .  FIG. 4  is the front view of the disc cutter  40 . The disc cutter  40  is supported rotatably to the cutterhead  30 . The disc cutter  40  is provided at the cutterhead  30  such that the rotation axis thereof (fixed axis AX 2  to be described below) intersects with the rotation axis AX 1  of the cutterhead  30 . The disc cutter  40  rotates as the disc cutter  40  is pressed against the excavation face of the tunnel, so that the rock is crushed. More particularly, with the cutterhead  30  rotating, application of a forward thrust force to the main body  10  and the cutterhead  30  causes the disc cutter  40  to rotate in contact with the rock under pressure. Rotation of the disc cutter  40  in contact with the rock under pressure causes rock crushing and rock cracking at the contact between a blade edge  44  of the disc cutter  40  and the rock. A crack occurring in the rock links with another crack adjacent thereto and then adjacent crushing occurs, resulting in excavation of the rock. Excavated muck generated in excavation of the rock is scooped in the chute hopper  21  open in the cutter chamber  30 C through the buckets  39  provided at the cutterhead  30  and then is conveyed backward by a belt conveyor  17 . 
     The disc cutter  40  includes a cutter ring  41 , a hub  42  supporting the cutter ring  41  unrotatably, a shaft (not illustrated) supporting the hub  42  rotatably through a bearing (not illustrated), and a pair of retainers  43  retaining the shaft with the hub  42  interposed therebetween in the axial direction. The central line of the shaft retained by the pair of retainers  43  is illustrated as the fixed axis AX 2  in  FIG. 3 . That is, the cutter ring  41  and the hub  42  are supported rotatably through the bearing not illustrated on the fixed axis AX 2 . The cutter ring  41  and the hub  42  are rotatable integrally. The pair of retainers  43  serves as a retaining member that sandwiches the cutter ring in the axial direction and retains the cutter ring rotatably. The cutter ring  41  rotates as the cutter ring  41  is pressed against the excavation face of the tunnel, so that the excavation face is excavated. 
     The cutter ring  41  has a blade edge  44 . The blade edge  44  protrudes forward and backward from the case  32  (refer to  FIGS. 3 and 11 ). The blade edge  44  is exposed from the front face and back face of the case  32 . The blade edge  44  protrudes forward from the front face  31  of the cutterhead  30 . 
     As illustrated in  FIGS. 3 and 4 , the disc cutter  40  is detachably housed in the case  32  provided at the cutterhead  30 . Inside the case  32 , provided is a bearing face that receives the press reaction force of the cutter ring  41  to the excavation face. The pair of retainers  43  of the disc cutter  40  is fixed to the bearing face. Key blocks  33  are used for positioning of the disc cutter  40  to the case  32 , namely, for positioning of the disc cutter  40  to the cutterhead  30 . The key blocks  33  are each detachably provided, from the cutter chamber side, to the case  32 . As illustrated in  FIG. 3 , with the disc cutter  40  having the retainers  43  abutting on the bearing face of the case  32 , the key blocks  33  are provided from the cutter chamber side. Each key block  33  and the corresponding retainer  43  are fastened through the case  32  with bolts  34 , so that the disc cutter  40  is fixed to the cutterhead  30 . As described above, the bearing face of the case  32  functions to support the press reaction force of the disc cutter  40  to the excavation face, and the key blocks  33  in cooperation with the bolts  34  function as a positioning member that positions the disc cutter  40  to the cutterhead  30  and restricts movement thereof. 
     [Method of Replacing Disc Cutter] 
     A method of replacing a disc cutter  40  will be described in detail with  FIG. 5 .  FIG. 5  is a schematic explanatory view of detachment of the disc cutter  40 . The disc cutter  40  is restricted by the key blocks  33  in detachment from the case  32  and in movement along the circumferential direction of the case  32 . As illustrated in  FIG. 5( a ) , the bolts  34  fixing the key blocks  33  to the case  32  are detached. As illustrated in  FIG. 5( b ) , the key blocks  33  are detached from the case  32 . The detachment of the key blocks  33  releases the restriction of the disc cutter  40 . As illustrated in  FIG. 5( c ) , the disc cutter  40  housed in the case  32  is rotated by 90° in the circumferential direction of the case  32 . As illustrated in  FIG. 5( d ) , the disc cutter  40  is detached from the case  32 . 
     In a case where a new disc cutter  40  is housed into the case  32 , the disc cutter  40  is inserted into the case  32 , inversely to the process in  FIG. 5( d ) . Inversely to the process in  FIG. 5( c ) , the disc cutter  40  inserted in the case  32  is rotated by 90°, inversely to the rotation in detachment, in the circumferential direction of the case  32 . Inversely to the process in  FIG. 5( b ) , the key blocks  33  are attached to the case  32 . Inversely to the process in  FIG. 5( a ) , the key blocks  33  are fixed to the case  32  with the bolts  34 . In this manner, fixed is the disc cutter  40  restricted by the key blocks  33  in detachment from the case  32  and in movement along the circumferential direction of the case  32 . 
     [Excavation Method by Tunnel Boring Machine] 
     An excavation method by such a tunnel boring machine  1  as above will be described. In the tunnel boring machine  1 , due to the drive motor  29 , the cutterhead  30  rotates with respect to the main body  10 . Each disc cutter  40  attached to the cutterhead  30  rotates as each disc cutter  40  is pressed against the excavation face of the tunnel, so that the rock is crushed. Excavated muck produced in excavation of the rock is scooped into the main body  10  by the buckets  39  and then is conveyed backward by the belt conveyor  17 . Because each disc cutter  40  wears due to excavation, for example, before the start of daily work or every predetermined period, the wear amount of the cutter ring  41  of each disc cutter  40  is measured. 
     [Measurement Device] 
     A measurement device  60  for use in measurement of the wear amount of the cutter ring  41  of a disc cutter  40 , in the tunnel boring machine  1 , will be described with  FIGS. 6  and  7 .  FIG. 6  is a schematic view of the configuration of the measurement device  60 .  FIG. 7  is a schematic explanatory view of a state where the measurement device  60  measures a disc cutter  40 . The measurement device  60  is provided closer to the cutter chamber  30 C (refer to  FIG. 1 ) in the tunnel boring machine  1 . The measurement device  60  includes a forward-and-backward variable slider  61  variable forward and backward in length, a front-and-back movement actuator  62  that slides a scanner  65  along the forward-and-backward variable slider  61 , an upward-and-downward variable slider  63  variable upward and downward in length, an up-and-down movement actuator  64  that slides the scanner  65  along the upward-and-downward variable slider  63 , the scanner  65 , and a case  69  that houses the forward-and-backward variable slider  61 , the front-and-back movement actuator  62 , the upward-and-downward variable slider  63 , the up-and-down movement actuator  64 , and the scanner  65 . The front-and-back movement actuator  62  varies the forward-and-backward variable slider  61  in length, to slide the scanner  65  forward and backward. The up-and-down movement actuator  64  varies the upward-and-downward variable slider  63  in length, to slide the scanner  65  upward and downward. 
     The scanner  65  serves as a 3D scanner, detects a target, and outputs three-dimensional data indicating the three-dimensional shape of the target to a data acquisition unit  115  in a measurement controller  110 . More particularly, the scanner  65  is capable of detecting the three-dimensional shape of the cutter ring  41  of a disc cutter  40  and a member  50  to be described below (refer to  FIG. 10 ). For example, the scanner  65  detects criterial three-dimensional data indicating the three-dimensional shape of a cutter ring  41  and a member  50  in the criterial state, such as just after attachment or before operation of a disc cutter  40  on which a new cutter ring  41  is mounted (namely, the cutter ring  41  has not worn yet) and measurement three-dimensional data indicating the three-dimensional shape of the cutter ring  41  and the member  50  in an operation state (namely, the cutter ring  41  is assumed to have worn to a certain extent). The scanner  65  outputs the detected criterial three-dimensional data and measurement three-dimensional data to the data acquisition unit  115  in the measurement controller  110 . 
     The scanner  65  is movable forward and backward by the forward-and-backward variable slider  61  and the front-and-back movement actuator  62  and is movable in the up-and-down direction by the upward-and-downward variable slider  63  and the up-and-down movement actuator  64 . 
     The scanner  65  adjustable in tilt angle is provided at the upward-and-downward variable slider  63 . The scanner  65  is capable of adjusting the angle of measurement to the cutter ring  41  of a disc cutter  40 . The angle of measurement corresponds to the angle between the central line C 1  of the blade edge  44  of the cutter ring  41  and the central line C 2  of the optical axis of the scanner  65 . 
     For example, the case  69  is provided at the cutterhead support  22 . With the measurement device  60  in non-measurement, the forward-and-backward variable slider  61 , the front-and-back movement actuator  62 , the upward-and-downward variable slider  63 , the up-and-down movement actuator  64 , and the scanner  65  are housed in the case  69 . In response to measurement of the measurement device  60 , the forward-and-backward variable slider  61 , the front-and-back movement actuator  62 , the upward-and-downward variable slider  63 , the up-and-down movement actuator  64 , and the scanner  65  are developed from the case  69 . 
     [Control System for Tunnel Boring Machine] 
     A controller  100  will be described with  FIG. 8 .  FIG. 8  is a block diagram of the configuration of the controller  100 . For example, the tunnel boring machine  1  is controlled by the controller  100 . For example, on the basis of operation information input through an operation board not illustrated or operating information input through an excavation management system not illustrated, the controller  100  actuates the tunnel boring machine  1 . A drive-motor control unit  101  in the controller  100  controls the drive motor  29  to rotate or stop rotating. 
     [Control System for Measurement Device] 
     As illustrated in  FIG. 8 , for example, the front-and-back movement actuator  62 , the up-and-down movement actuator  64 , and the scanner  65  in the measurement device  60  are controlled by the measurement controller  110 . A measurement target setting unit  111  in the measurement controller  110  controls the drive motor  29  to rotate the cutterhead  30  such that the scanner  65  can measure a disc cutter  40  as the measurement target. A front-and-back movement control unit  112  in the measurement controller  110  controls the front-and-back movement actuator  62  to adjust the position in the front-and-back direction of the scanner  65  on the basis of the disc cutter  40  as the measurement target. An up-and-down movement control unit  113  in the measurement controller  110  controls the up-and-down movement actuator  64  to adjust the position in the up-and-down direction of the scanner  65  on the basis of the disc cutter  40  as the measurement target. A scanner control unit  114  in the measurement controller  110  controls the scanner  65  to perform three-dimensional measurement. The data acquisition unit  115  in the measurement controller  110  acquires three-dimensional data from the scanner  65 . A wear-amount calculation unit  116  in the measurement controller  110  calculates the wear amount of the cutter ring  41  of the disc cutter  40 , on the basis of the acquired three-dimensional data. 
     [Computer System] 
     A computer system  1000  will be described with  FIG. 9 .  FIG. 9  is a block diagram of the computer system  1000  according to the present embodiment. The controller  100  described above includes the computer system  1000 . The computer system  1000  includes a processor  1001  like a central processing unit (CPU), a main memory  1002  including a nonvolatile memory like a read only memory (ROM) and a volatile memory like a random access memory (RAM), a storage  1003 , and an interface  1004  including an input/output circuit. The function of the controller  100  and the function of the measurement controller  110 , described above, are stored as a program in the storage  1003 . The processor  1001  reads the program from the storage  1003 , develops the program in the main memory  1002 , and performs the processing described above, in accordance with the program. Note that the program may be distributed to the computer system  1000  through a network. 
     Additional Member According to First Embodiment 
     A member  50  will be described with  FIGS. 10 and 11 .  FIG. 10  is a front view of members  50  each provided at a key block by welding, in a first embodiment of the present invention.  FIG. 11  is a side view of a case  32  on which a disc cutter  40  is mounted with the key blocks  33  each provided with the member  50 , in the first embodiment of the present invention. The members  50  are used in measurement of the wear amount of the cutter ring  41  of the disc cutter  40  with the three-dimensional shape measurement device (hereinafter, referred to as the “measurement device”)  60 . More particularly, the members  50  are used in alignment in measurement with the measurement device  60 . The members  50  together with the cutter ring  41  are located detectably in the detection area of the measurement device  60 . Thus, in measurement with the measurement device  60 , the members  50  are detected together with the cutter ring  41 . 
     The members  50  are each located so as to be less likely to wear in excavation of the tunnel boring machine  1  and so as not to interfere with excavation and replacement of the disc cutter  40 . The members  50  are each provided at a part constant in relative position to the cutter ring  41  of the disc cutter  40 . The constant relative position means that the positional relationship between the cutter ring  41  and each member  50  does not vary between a state just after attachment or before operation of the disc cutter  40  and the state of the disc cutter  40  in operation. The members  50  are provided near the cutter ring  41 . In the present embodiment, the members  50  are provided at the key blocks  33  that restrict movement of the disc cutter  40  along the circumferential direction of the case  32 . 
     The members  50  are provided closer to the cutter chamber  30 C in the tunnel boring machine  1 . 
     An exemplary shape of member  50  will be described with  FIGS. 12 to 14 .  FIG. 12  is a front view of an exemplary member  50 .  FIG. 13  is a side view of the member  50  illustrated in  FIG. 12 .  FIG. 14  is a plan view of the member  50  illustrated in  FIG. 12 . The member  50  is formed of a combination of a wall  51 , a wall  52 , a wall  53 , a wall  54 , and a wall  55  planar in shape. The wall  51  is rectangular in shape. The wall  51  is provided in parallel to a surface  33   a  of a key block  33 . The wall  52  and the wall  53  are each trapezoidal in shape. The wall  52  and the wall  53  are each provided inclining at an intermediate portion of the wall  51 . The wall  52  and the wall  53  are each provided in a plane crossing the surface  33   a  of the key block  33 . A circumferential edge  52   a  of the wall  52  and a circumferential edge  53   a  of the wall  53  are each joined to the intermediate portion of the wall  51 , resulting in formation of bends. A circumferential edge  52   b  of the wall  52  and a circumferential edge  53   b  of the wall  53  are joined together, resulting in formation of a bend. The wall  54  and the wall  55  are each triangular in shape. The wall  54  is provided covering the opening surrounded by the upper portion of the wall  51 , the upper portion of the wall  52 , and the upper portion of the wall  53 . The wall  55  is provided covering the opening surrounded by the lower portion of the wall  51 , the lower portion of the wall  52 , and the lower portion of the wall  53 . The wall  52 , the wall  53 , the wall  54 , and the wall  55  each serve as part of formation of a humped shape protruding inward in the radial direction of the case  32  from a surface  33   b  of the key block  33 . The wall  52 , the wall  53 , the wall  54 , and the wall  55  each serve as part of formation of a triangular prism. 
     The respective normals of the wall  51 , the wall  52 , the wall  53 , the wall  54 , and the wall  55  extend in different directions and cross each other. 
     The wall  51  has a length d 11  approximately the same as the width dk 1  of the key block  33 . The wall  51  has a length d 12  shorter than the distance dk 2  from the key block  33  to the cutter ring  41 . The distance d 13  from the wall  51  to the joint between the wall  52  and the wall  53  is approximately the same as the thickness dk 3  of the key block  33  (refer to  FIG. 11 ). The wall  51  protrudes outward from the wall  52  and the wall  53 . 
     Preferably, such a plurality of members  50  as above is provided around a disc cutter  40 . In the present embodiment, two members  50  are provided around a disc cutter  40 . 
     Preferably, as in the present embodiment, one member  50  is provided on one side in the axial direction of a cutter ring  41  (direction of the fixed axis AX 2 ) and another member  50  is provided on the other side. 
     In the present embodiment, such a member  50  is attached to a key block  33  by welding. 
     The member  50  has a plurality of faces facing in different directions. The plurality of faces of the member  50  varies mutually discontinuously. 
     The member  50  provided includes a humped shape protruding toward the cutter chamber  30 C. In the present embodiment, the humped shape included in the member  50  protrudes from the surface  33   b  of the key block  33 . 
     [Method of Measuring Wear Amount of Cutter Ring of Disc Cutter] 
     Next, a method/processing of measuring the wear amount of the cutter ring  41  of a disc cutter  40  with the measurement device  60  in the tunnel boring machine  1  including disc cutters  40  will be described.  FIG. 15  is a flowchart of an exemplary processing procedure of a method of measuring the cutter ring  41  of a disc cutter  40  in the criterial state.  FIG. 16  is a flowchart of an exemplary processing procedure of a method of measuring the cutter ring  41  of a disc cutter  40  in an operation state. Before measurement of the wear amount of the cutter ring  41  of a disc cutter  40  in an operation state in the tunnel boring machine  1 , the processing illustrated in  FIG. 15  is performed at least once, resulting in acquisition of criterial three-dimensional data of the disc cutter  40 . Such criterial three-dimensional data is preferably acquired in response to mounting of a new disc cutter  40  or mounting of a disc cutter  40  on which a new cutter ring is mounted. 
     The measurement target setting unit  111  in the measurement controller  110  sets a disc cutter  40  as the measurement target (Step S 11 ). For example, the order of measurement of all disc cutters  40  mounted on the cutterhead  30  is stored in a storage unit not illustrated. In accordance with the stored order, the measurement target setting unit  111  sets the corresponding disc cutter  40  as the measurement target. The measurement target setting unit  111  in the measurement controller  110  controls the drive motor  29  to rotate the cutterhead  30  such that the scanner  65  can measure the disc cutter  40  as the measurement target. The measurement controller  110  proceeds to Step S 12 . 
     The measurement controller  110  moves the scanner  65  on the basis of the disc cutter  40  as the measurement target (Step S 12 ). More particularly, the front-and-back movement control unit  112  in the measurement controller  110  controls the front-and-back movement actuator  62  to adjust the position in the front-and-back direction of the scanner  65  on the basis of the disc cutter  40  as the measurement target. The up-and-down movement control unit  113  in the measurement controller  110  controls the up-and-down movement actuator  64  to adjust the position in the up-and-down direction of the scanner  65  on the basis of the disc cutter  40  as the measurement target. The measurement controller  110  proceeds to Step S 13 . 
     The scanner control unit  114  in the measurement controller  110  controls the scanner  65  to perform three-dimensional measurement of the disc cutter  40  as the measurement target (Step S 13 ). The scanner control unit  114  causes the scanner  65  to scan the three-dimensional shape of the disc cutter  40  as the measurement target. The scanner control unit  114  measures the three-dimensional shape of the cutter ring  41  in the criterial state together with the three-dimensional shape of the members  50 . The measurement controller  110  proceeds to Step S 14 . 
     The data acquisition unit  115  in the measurement controller  110  acquires data measured by the scanner  65  in the measurement device  60  (Step S 14 ). The measurement controller  110  proceeds to Step S 15 . 
     The data acquisition unit  115  in the measurement controller  110  stores the acquired data as the criterial three-dimensional data of the disc cutter  40  into a storage unit  120  (Step S 15 ). The criterial three-dimensional data of the disc cutter  40  includes three-dimensional shape data of the cutter ring  41  and three-dimensional shape data of the members  50  in the criterial state. The data acquisition unit  115  stores the acquired criterial three-dimensional data in association with identification information regarding the disc cutter  40  as the measurement target. The measurement controller  110  proceeds to Step S 16 . 
     The measurement controller  110  determines whether or not a disc cutter  40  as the next measurement target is present (Step S 16 ). In a case where a disc cutter  40  yet to be measured is present, the measurement controller  110  determines that a disc cutter  40  as the next measurement target is present (Yes in Step S 16 ), and then performs the processing in Step S 11  again. In a case where all disc cutters  40  have been measured, the measurement controller  110  determines that no disc cutter  40  as the next measurement target is present (No in Step S 16 ), and then terminates the processing. 
     In this manner, with the measurement device  60 , the measurement controller  110  acquires and stores the criterial three-dimensional data of the cutter ring  41  of each disc cutter  40  in the criterial state and the members  50  each provided at the part constant in relative position to the cutter ring  41 . 
     After acquisition of the criterial three-dimensional data, the processing illustrated in  FIG. 16  is performed, for example, before the start of daily work or every predetermined period, resulting in measurement of the wear amount of the cutter ring  41  of each disc cutter  40  in the tunnel boring machine  1 . Step S 21 , Step S 22 , and Step S 28  are similar in processing to Step S 11 , Step S 12 , and Step S 16  described above, respectively, and thus the descriptions thereof will be omitted. 
     In Step S 23 , the scanner control unit  114  in the measurement controller  110  controls the scanner  65  to perform three-dimensional measurement of the disc cutter  40  as the measurement target. The scanner control unit  114  measures the three-dimensional shape of the cutter ring  41  in an operation state together with the three-dimensional shape of the members  50 . The measurement controller  110  proceeds to Step S 24 . 
     The data acquisition unit  115  in the measurement controller  110  acquires data measured by the scanner  65  in the measurement device  60  (Step S 24 ). The measurement controller  110  proceeds to Step S 25 . 
     The data acquisition unit  115  in the measurement controller  110  stores the acquired data as the measurement three-dimensional data of the disc cutter  40  into the storage unit  120  (Step S 25 ). The measurement three-dimensional data of the disc cutter  40  includes three-dimensional shape data of the cutter ring  41  and three-dimensional shape data of the members  50  in the operation state. The measurement controller  110  proceeds to Step S 26 . 
     The wear-amount calculation unit  116  in the measurement controller  110  reads the criterial three-dimensional data of the disc cutter  40  with reference to the identification information regarding the disc cutter  40 , and calculates the wear amount of the cutter ring  41  of the disc cutter  40 , on the basis of the criterial three-dimensional data and the measurement three-dimensional data (Step S 26 ). The measurement controller  110  collates the criterial three-dimensional data and the measurement three-dimensional data, to calculate the wear amount of the cutter ring  41 .  FIG. 17  is a schematic explanatory view of alignment in measurement. As illustrated in  FIG. 17( a ) , the wear-amount calculation unit  116  performs alignment between the criterial three-dimensional data indicated with broken lines and the measurement three-dimensional data indicated with solid lines, with respective members  50  as the criterion, namely, such that the respective members  50  are superimposed together. As illustrated in  FIG. 17( b ) , the difference between the blade edge  44  in the criterial three-dimensional data and the blade edge  44  in the measurement three-dimensional data after alignment corresponds to the wear amount W of the cutter ring  41 . The measurement controller  110  proceeds to Step S 27 . 
     The wear-amount calculation unit  116  in the measurement controller  110  stores, into the storage unit  120 , the calculated wear amount of the cutter ring  41  of the disc cutter  40  in association with the identification information regarding the disc cutter  40  (Step S 27 ). The measurement controller  110  proceeds to Step S 28 . 
     In a case where a disc cutter  40  yet to be measured is present, the measurement controller  110  determines that a disc cutter  40  as the next measurement target is present (Yes in Step S 28 ), and then performs the processing in Step S 21  again. In a case where all disc cutters  40  have been measured, the measurement controller  110  determines that no disc cutter  40  as the next measurement target is present (No in Step S 28 ), and then terminates the processing. 
     Due to such processing as above, the wear amount of the cutter ring  41  of each disc cutter  40  in the tunnel boring machine  1  in an operation state is calculated. 
     Effects 
     In the present embodiment, with a member  50  provided at a part constant in relative position to the cutter ring  41  of a disc cutter  40 , alignment is performed between the criterial three-dimensional data and the measurement three-dimensional data measured by the measurement device  60 . Because the member  50  is located so as not to wear, the member  50  is inhibited from varying in shape between the criterial three-dimensional data and the measurement three-dimensional data. According to the present embodiment, highly accurate alignment can be performed between the criterial three-dimensional data and the measurement three-dimensional data. In this manner, the present embodiment enables highly accurate measurement of the wear amount of the cutter ring  41 . 
     According to the present embodiment, alignment with the member  50  enables achievement of the targeted accuracy of measurement, regardless of the shape of the member  50 . According to the present embodiment, alignment with the member  50  enables achievement of the targeted accuracy of measurement, regardless of the wear amount of the cutter ring  41 . According to the present embodiment, alignment with the member  50  enables achievement of the targeted accuracy of measurement, regardless of the angle of measurement. 
     In the present embodiment, with the member  50 , alignment is performed between the criterial three-dimensional data and the measurement three-dimensional data. Thus, highly accurate acquisition of the coordinates and posture of the scanner  65  in the measurement device  60  need not be obtained. According to the present embodiment, the wear amount of the cutter ring  41  can be easily measured. 
     In the present embodiment, the member  50  has a plurality of faces facing in different directions. According to the present embodiment, regardless of the relative position between the measurement device  60  and the member  50  with the cutter ring  41  of the disc cutter  40 , geometric features of the member  50  can be detected, resulting in achievement of more accurate detection. According to the present embodiment, regardless of the relative position between the measurement device  60  and the member  50  with the cutter ring  41  of the disc cutter  40 , the wear amount of the cutter ring  41  can be measured highly accurately. 
     In the present embodiment, the member  50  is provided closer to the cutter chamber  30 C in the tunnel boring machine  1 . According to the present embodiment, in excavation of the tunnel boring machine  1 , the excavation can be inhibited from being interfered with the member  50 , and the member  50  can be inhibited from wearing. 
     In the present embodiment, the member  50  together with the cutter ring  41  is located detectably in the detection area of the measurement device  60 . According to the present embodiment, the criterial three-dimensional data and the measurement three-dimensional data that indicate the three-dimensional shape of the cutter ring  41  and the member  50  can be easily acquired. 
     In the present embodiment, the member  50  is provided at a key block  33 . According to the present embodiment, the member  50  can be located so as not to interfere with replacement of the disc cutter  40 . 
     In the present embodiment, the member  50  is attached to the key block  33  by welding. If the member  50  is damaged or deformed, the member  50  can be easily replaced together with the key block  33 . 
     In the present embodiment, such a plurality of members  50  is provided around the disc cutter  40 . According to the present embodiment, in measurement of the measurement device  60 , an improvement can be made in the accuracy of alignment. 
     In the present embodiment, one member  50  is provided on one side in the axial direction of the cutter ring  41  and another member  50  is provided on the other side. According to the present embodiment, regardless of the relative position between the measurement device  60  and the members  50  with the cutter ring  41  of the disc cutter  40 , the members  50  can be detected. Thus, the present embodiment enables highly accurate alignment between the criterial three-dimensional data and the measurement three-dimensional data. According to the present embodiment, regardless of the relative position between the measurement device  60  and the members  50  with the cutter ring  41  of the disc cutter  40 , more accurate detection can be achieved. 
     In the present embodiment, each member  50  provided includes a humped shape protruding toward the cutter chamber  30 C. According to the present embodiment, the accuracy of detection of the members  50  is inhibited from deteriorating due to the influence of clogging, for example, due to excavated muck in excavation. 
     In the present embodiment, the members  50  are each provided replaceably at a key block  33 . According to the present embodiment, for example, in a case where any member  50  is damaged, only the member  50  can be easily replaced. According to the present embodiment, the members  50  can be easily mounted on the conventional cutterhead  30 . 
     [Modification of Position at which Additional Member is Provided] 
     Such a member  50  as above may be fixed to a case  32 , a retainer  43  (retaining member), or a hub  42  by welding, instead of to a key block  33 . In this case, at the time of replacement, the member  50  needs to be detached by cutting. 
     [First Modification of Shape of Additional Member] 
     An exemplary shape of a member  50 A will be described with  FIGS. 18 to 20 .  FIG. 18  is a front view of an exemplary member  50 A.  FIG. 19  is a side view of the member  50 A illustrated in  FIG. 18 .  FIG. 20  is a plan view of the member  50 A illustrated in  FIG. 18 . The member  50 A has a wall  51 A different in shape from the wall  51  of the member  50 , and is smaller than the member  50 . The wall  51 A has a length d 21  shorter than the length d 11  of the wall  51  of the member  50 . The wall  51 A has a length d 22  the same as the length d 12  of the wall  51  of the member  50 . The distance d 23  from the wall  51 A to the joint between a wall  52 A and a wall  53 A is the same as the distance d 13  of the member  50 . A circumferential edge  52   a  of the wall  52  and a circumferential edge  53   a  of the wall  53  are each joined to an end portion of the wall  51 A. The wall  51 A does not protrude outward from the wall  52  and the wall  53 . Such a shape of the member  50 A can be made smaller than the member  50 . 
     [Second Modification of Shape of Additional Member] 
     An exemplary shape of a member  50 B will be described with  FIGS. 21 to 23 .  FIG. 21  is a front view of an exemplary member  50 B.  FIG. 22  is a side view of the member  50 B illustrated in  FIG. 21 .  FIG. 23  is a plan view of the member  50 B illustrated in  FIG. 21 . The member  50 B is smaller than the member  50 A. A wall  51 B has a length d 31  the same as the length d 21  of the wall  51 A of the member  50 A. The wall  51 B has a length d 32  shorter than the length d 22  of the wall  51 A of the member  50 A. The distance d 33  from the wall  51 B to the joint between a wall  52 B and a wall  53 B is the same as the distance d 23  of the member  50 A. Such a shape of member  50 B can be made smaller than the member  50  and the member  50 A. 
     [Comparison with Conventional Technique] 
     Here, measurement with the measurement device  60  and measurement with a conventional technique are evaluated in the accuracy of measurement.  FIG. 24  is an explanatory graph of differences in the accuracy of measurement from the conventional technique.  FIG. 25  is an explanatory graph of influence on the accuracy of measurement due to the angle of measurement.  FIG. 26  is an explanatory graph of influence on the accuracy of measurement due to the angle of measurement. With a combination of the following three conditions, measurement was performed ten times in each condition. 
     (Condition 1) Measurement is performed with a variation in the shape of a member  50  for use in alignment. More particularly, measurement with the measurement device  60  with the member  50 , the member  50 A, and the member  50 B described above for alignment and measurement with the conventional technique are performed. “Shape 1” indicates measurement with the member  50 , “Shape 2” indicates measurement with the member  50 A, “Shape 3” indicates measurement with the member  50 B, and “Conventional Technique” indicates measurement with the conventional technique. 
     Here, measurement with the conventional technique will be described with  FIG. 27 .  FIG. 27  is a schematic explanatory view of alignment with the conventional technique. The conventional technique is a technique in which, without any member for alignment, the wear amount is measured with alignment, for example, based on the shape of a shoulder  41   a  that the cutter ring  41  of a disc cutter  40  has. A broken line indicates three-dimensional data acquired in the criterial state, a solid line indicates three-dimensional data acquired in an operation state, and a dot-and-dash line indicates three-dimensional data acquired in an operation state with further wear. From  FIG. 27 , because of alignment based on the shape of the shoulder  41   a  of the cutter ring  41 , in a case where the shoulder  41   a  wears due to further wearing, obviously, it is difficult to perform alignment properly. 
     (Condition 2) Measured is the wear amount of the cutter ring  41  of the disc cutter  40  that varies from 8 mm to 10 mm and then to 12 mm. 
     (Condition 3) Measurement is performed at two angles of 0° and 30° as the angle of measurement. 
     Evaluation is performed on the basis of comparison in the root mean square error (RMSE) between a measured value f k  with the measurement device  60  and a gage measured value y k  with a gauge at each of n number of measurement points, calculated with the following Mathematical Expression 1. Herein, the measurement point in front of the scanner  65  on the circumference of the disc cutter  40  is defined as 0°, and measurement is performed in the range from −40° to 40°. In the range, the wear amount is measured every 2° for approximately 40 points in total. Note that the targeted RMSE is 1 mm. 
     
       
         
           
             
               
                 
                   RMSE 
                   = 
                   
                     
                       
                         1 
                         n 
                       
                       ⁢ 
                       
                         
                           ∑ 
                           k 
                           n 
                         
                         ⁢ 
                         
                             
                         
                         ⁢ 
                         
                           
                             ( 
                             
                               
                                 f 
                                 k 
                               
                               - 
                               y 
                             
                             ) 
                           
                           2 
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   1 
                   ) 
                 
               
             
           
         
       
     
     From  FIG. 24 , obviously, Shape 1, Shape 2, and Shape 3 are smaller in RMSE than the conventional technique. Obviously, in each of Shape 1, Shape 2, and Shape 3, the difference in RMSE due to the differences in the wear amount is small. Regardless of the wear amount of the cutter ring  41  of the disc cutter  40 , Shape 1, Shape 2, and Shape 3 each fall below the targeted RMSE, resulting in achievement of the targeted accuracy of measurement. 
     From  FIGS. 25 and 26 , regardless of the angle of measurement, Shape 1, Shape 2, and Shape 3 are smaller in RMSE than the conventional technique. The conventional technique is larger in RMSE at an angle of measurement of 30° than at an angle of measurement of 0°. Shape 1, Shape 2, and Shape 3 are slightly larger in RMSE at an angle of measurement of 30° than at an angle of measurement of 0°, but fall below the targeted RMSE. Regardless of the angle of measurement, Shape 1, Shape 2, and Shape 3 fall below the targeted RMSE, resulting in achievement of the targeted accuracy of measurement. 
     In the above, the member  50 , the member  50 A, and the member  50 B are each formed of a combination of the wall  51 , the wall  52 , the wall  53 , the wall  54 , and the wall  55  planar in shape, but this is not the only configuration. The member  50 , the member  50 A, and the member  50 B may each be formed of a combination of a plurality of curved faces or may each be formed of a combination of a planar face and a curved face. 
     In the above, the controller  100  and the measurement controller  110  are separately provided, but the present invention is not limited to this. The controller  100  and the measurement controller  110  may be integrally provided. 
     In the above, the scanner  65  is movable forward and backward by the forward-and-backward variable slider  61  and the front-and-back movement actuator  62  and is movable in the up-and-down direction by the upward-and-downward variable slider  63  and the up-and-down movement actuator  64 , but moving means are not limited to this. For example, the scanner  65  may be mounted on an unmanned flight vehicle, such as a drone. 
     REFERENCE SIGNS LIST 
     
         
         
           
               1  TUNNEL BORING MACHINE 
               10  MAIN BODY 
               20  BELT CONVEYOR 
               29  DRIVE MOTOR 
               30  CUTTERHEAD 
               32  CASE 
               33  KEY BLOCK 
               40  DISC CUTTER 
               41  CUTTER RING 
               42  HUB 
               43  RETAINER (RETAINING MEMBER) 
             44 BLADE EDGE 
               50  MEMBER 
               60  THREE-DIMENSIONAL SHAPE MEASUREMENT DEVICE (MEASUREMENT DEVICE) 
               61  FORWARD-AND-BACKWARD VARIABLE SLIDER 
               62  FRONT-AND-BACK MOVEMENT ACTUATOR 
               63  UPWARD-AND-DOWNWARD VARIABLE SLIDER 
               64  UP-AND-DOWN MOVEMENT ACTUATOR 
               65  SCANNER 
               69  CASE 
               100  CONTROLLER 
               110  MEASUREMENT CONTROLLER 
               111  MEASUREMENT TARGET SETTING UNIT 
               112  FRONT-AND-BACK MOVEMENT CONTROL UNIT 
               113  UP-AND-DOWN MOVEMENT CONTROL UNIT 
               114  SCANNER CONTROL UNIT 
               115  DATA ACQUISITION UNIT 
               116  WEAR-AMOUNT CALCULATION UNIT