JP6234104B2 - Tunnel axial force display mechanism, tunnel axial force display bolt, and tunnel excavation method - Google Patents

Description

  The present invention relates to a tunnel axial force display mechanism, a tunnel axial force display bolt, and a tunnel axial force display mechanism for displaying the axial force of a lock bolt driven into a natural ground from a tunnel inner wall surface so as to be visually confirmed. It relates to the method of digging.

  In order to display the axial force of a rock bolt for tunnel support so that it can be visually confirmed, the inner and outer bearing plates on the inner wall surface of the tunnel inner wall are projected to the protruding portion of the lock bolt driven into the ground from the inner wall surface of the tunnel. There is a structure in which a load cell is installed so as to be sandwiched between the outer pressure plates, a nut is screwed into a lock bolt from the outside of the outer pressure plate, and the axial force of the lock bolt is displayed by a Bourdon tube provided in the load cell (Patent Document 1). reference).

  Furthermore, a holding member is provided between the nut and the inner wall surface of the tunnel that are screwed into the lock bolt that is driven into the ground from the inner wall surface of the tunnel so that the axial force of the lock bolt can be visually confirmed more easily. A so-called chemical light discoloring member that changes color when a load is applied is held in the groove of the holding portion in a state that is visible from the outside, and the load applied to the holding member by the tunnel inner wall surface and the nut sandwiching the holding member becomes a predetermined value. There is a structure in which the axial force of the lock bolt is displayed by discoloration of the discoloring member so that the load is not transmitted to the discoloring member when less than the predetermined value, and the load is transmitted to the discoloring member when the value is greater than a predetermined value (Patent Document) 2).

JP 2001-133392 A Japanese Patent No. 3669765

  By the way, the structure that displays the axial force with the Bourdon tube provided in the load cell can display the axial force corresponding to the increase / decrease even when the axial force of the lock bolt increases / decreases, but the Bourdon tube Since it is necessary to confirm the axial force from the scale, there is a problem of poor visibility. In particular, in a dark work space in a tunnel, if the visibility is inferior, the work for confirming the axial force requires a great amount of work, and this problem becomes more prominent.

  In addition, the structure that displays the axial force by the color change of the chemical light can easily visually check the axial force of a predetermined value or more by the color change of the chemical light due to the chemical change, and although it is excellent in visibility, Since the color of the discoloring member does not return to the original color, there is a problem that when the axial force of the lock bolt increases or decreases, the axial force cannot be displayed corresponding to the increase or decrease change. Therefore, what is excellent in the visibility of visual confirmation, and what can display an axial force corresponding to the increase / decrease change of the axial force of a lock bolt are calculated | required.

  The present invention is proposed in view of the above-described problems, and is excellent in visual confirmation visibility, enables efficient confirmation of the axial force of the lock bolt, and responds to changes in the axial force of the lock bolt. It is an object of the present invention to provide a tunnel axial force display mechanism capable of displaying axial force, a tunnel axial force display bolt, and a tunnel excavation method using the tunnel axial force display mechanism.

The tunnel axial force display mechanism of the present invention includes a lock bolt driven into a natural ground, and a ground deformation detection which is connected to a rear end portion of the lock bolt so as to transmit the axial force of the lock bolt. An axial force display bolt, and the axial force display bolt has a main body and a colored display surface at the rear end, and is generated against the pushing force generated in the ground which is transmitted to the main body. different from the movable section which is furnished on the body so as to relatively move in the axial direction, and a transparent plate provided on the rear side of the colored display surface, and the colored display surface in response to the axial force of the lock bolt A colored fluid of a color is visibly enclosed and provided to cover the colored display surface, and the colored display according to a change in the distance between the colored display surface and the transparent plate due to the relative movement Colored fluid seal installed with variable thickness covering the surface Characterized in that it is composed of a body.
According to this, the thickness of the colored fluid enclosure that covers the colored display surface changes according to the axial force generated in the lock bolt, and the color that can be seen from the transparent plate changes. The axial force generated in the bolt can be recognized by the color change. That is, it is excellent in the visibility of the visual confirmation, and it is possible to efficiently check the axial force of the lock bolt and to detect the ground deformation early. In addition, when changing the color visually recognized by a chemical change or a method in which the bag containing the paint ruptures, the color does not return to the original color after being temporarily changed. Then, the colored fluid enclosure will be displayed darker, and once the large axial force that has been generated is reduced, the movable part will return and the color of the colored display surface will be displayed. The axial force can be displayed. In addition, when an axial force indicator is provided on the lock bolt itself, it becomes a very expensive lock bolt. On the other hand, in the configuration in which the axial force indicator bolt is connected to the rear end of the lock bolt, a low-cost short shaft is provided. It becomes possible to use force display bolts, and moreover, the axial force display bolts can be used in large numbers because of its low cost, and it is possible to detect ground deformation more accurately by using many in a wide range. It becomes possible. Moreover, an axial force indication bolt can be installed as part of the flow of normal rock bolt driving, and the workability is excellent.

The tunnel axial force display mechanism of the present invention is characterized in that the axial force display bolt is connected to a rear end portion of the lock bolt via a separate coupler.
According to this, it is possible to connect the same axial force indication bolt to various lock bolts using couplers that can be connected to various existing lock bolts, dramatically improving the versatility of axial force indication bolts. In addition, the manufacturing cost and construction cost can be greatly reduced by using the same axial force indicating bolt.

The tunnel axial force display mechanism according to the present invention is characterized in that an expansion lens is provided on the rear side of the transparent plate to extend a visible color range.
According to this, the color of the axial force display can be visually confirmed from various positions, and the visual confirmation of the axial force display can be further improved even more surely even in the work space in the dark tunnel. be able to.

In the tunnel axial force display mechanism of the present invention, the expansion lens is a spherical lens, and the spherical lens is mounted in a cylindrical cap, and the front side of the cylindrical cap is fitted to the rear side of the axial force display bolt. It is characterized by being able to.
According to this, the spherical lens which is an expansion lens can be easily attached to the axial force display bolt. In addition, it is possible to visually recognize the color of the axial force display from a wider area even if it is not directly in front of the axial force display bolt, and the work of checking the axial force of the lock bolt can be made more efficient, and the display color Change can be recognized more quickly, so that it is possible to recognize the change of axial force and the ground deformation more quickly.

The tunnel axial force display bolt of the present invention is connected to the rear end portion of a lock bolt that is driven into a natural ground, and is a tunnel shaft for detecting ground deformation that is provided so as to transmit the axial force of the lock bolt. A force indicating bolt having a main body and a colored display surface at the rear end, and a shaft corresponding to the axial force of the lock bolt generated against the pushing force generated in the ground transmitted to the main body A movable part built in the main body so as to move relative to the direction, a transparent plate provided on the rear side of the colored display surface, and a colored fluid having a color different from that of the colored display surface are visibly enclosed. The color display surface is provided so as to cover the color display surface, and the thickness covering the color display surface is changeable according to a change in the distance between the color display surface and the transparent plate due to the relative movement. A colored fluid enclosure To.
According to this, the thickness of the colored fluid enclosure that covers the colored display surface changes according to the axial force generated in the lock bolt, and the color that can be seen from the transparent plate changes. It becomes possible to recognize the axial force generated in the bolt by the color change. That is, it is excellent in the visibility of the visual confirmation, and it is possible to efficiently check the axial force of the lock bolt and to detect the ground deformation early. In addition, when changing the color visually recognized by a chemical change or a method in which the bag containing the paint ruptures, the color does not return to the original color after being temporarily changed. Then, the colored fluid enclosure will be displayed darker, and once the large axial force that has been generated is reduced, the movable part will return and the color of the colored display surface will be displayed. The axial force can be displayed. In addition, when an axial force indicator is provided on the lock bolt itself, it becomes a very expensive lock bolt, whereas an axial force indicator bolt connected to the rear end of the lock bolt is a low-cost short axial force. It can be used as a display bolt, and moreover, it can be used in many cases due to the low cost of the axial force display bolt, and a large number of axial force display bolts can be used in a wide range to detect ground deformation more accurately. It becomes possible to do. Moreover, an axial force indication bolt can be installed as part of the flow of normal rock bolt driving, and the workability is excellent.

In the tunnel excavation method of the present invention, for each predetermined excavation length of the tunnel, the tunnel axial force display mechanism of the present invention is provided at every predetermined interval in the tunnel excavation direction and at every predetermined interval in the tunnel circumferential direction, and the tunnel axial force It is characterized by digging a tunnel while detecting deformation due to extrusion of surrounding ground with a display mechanism.
According to this, the tunnel excavation work can be performed while accurately detecting the deformation due to the extrusion of the surrounding natural ground at low cost, and the tunnel can be constructed economically and safely.

  According to the present invention, it is possible to efficiently check the axial force of the lock bolt, and to display the axial force corresponding to the increase / decrease change of the axial force of the lock bolt. it can.

Explanatory drawing which shows a part of tunnel in which the axial force display mechanism for tunnels of 1st Embodiment was provided. Cross-sectional explanatory drawing explaining the mechanism which axial force generate | occur | produces in a lock bolt by the deformation of a natural ground. (A) is side explanatory drawing which shows the structural member of the axial force display mechanism for tunnels of 1st Embodiment, (b) is a side view which shows the axial force display mechanism for tunnels of 1st Embodiment in an installation state. (A) is a partial expanded sectional view which shows the periphery of the axial force display volt | bolt of the axial force display mechanism for tunnels of 1st Embodiment, (b) is the AA arrow directional view of the same figure (a). (A)-(c) is fragmentary sectional explanatory drawing explaining operation | movement of the axial force display mechanism for tunnels of 1st Embodiment. (A)-(c) is front explanatory drawing seen from the tunnel space explaining operation | movement of the axial force display mechanism for tunnels of 1st Embodiment. (A) is side explanatory drawing which shows the structural member of the axial force display mechanism for tunnels of 2nd Embodiment, (b) is a side view which shows the axial force display mechanism for tunnels of 2nd Embodiment in an installation state, (c) Is a view taken along the line B-B in FIG. (A) is side explanatory drawing which shows the structural member of the axial force display mechanism for tunnels of 3rd Embodiment, (b) is a side view which shows the axial force display mechanism for tunnels of 3rd Embodiment in an installation state, (c) Is a CC line arrow view of the same figure (b).

[Axial Force Display Mechanism for Tunnel of First Embodiment]
The tunnel axial force display mechanism 1 according to the first embodiment of the present invention is provided for each lock bolt 2 driven into the ground 101 at predetermined intervals in the tunnel space S as shown in FIGS. 1 and 2, for example. In addition, the lock bolt 2 and the axial force display mechanism 1 for the tunnel are provided at predetermined intervals in the tunneling direction of the tunnel space S and are arranged radially at predetermined intervals in the circumferential direction of the tunnel.

  In the illustrated example, the shotcrete 102 is formed along the inner surface of the ground 101, and the inner surface of the shotcrete 102 is used as the inner wall surface 103 of the tunnel, and the lock bolt 2 is driven from the inner wall surface 103 of the tunnel. A natural ground arch 104 is formed. An axial force display bolt 3 is connected to the rear end portion of each of these lock bolts 2 to constitute a tunnel axial force display mechanism 1. 2 is cover concrete provided to cover the shotcrete 102 and the axial force display mechanism 1 for the tunnel in a later step.

  When deformation occurs in the natural ground 101 such as the natural arch 104, the pushing force P is generated so that the natural ground 101 is pushed out toward the tunnel space S as shown by the white arrow in FIG. The lock bolt 2 to be produced has an axial tensile force, that is, an axial force. As will be described later, an axial force display bolt 3 that changes the display color in accordance with the magnitude of the axial force is provided. The axial force generated in the lock bolt 2 is transmitted to the axial force display bolt 3, and the display color corresponding to the push force P and the magnitude of the axial force is displayed.

  1 in FIG. 1 is a face located at the forefront of the tunnel being excavated, and L between two-dot chain lines is a predetermined length of excavation at a time, and when excavating the tunnel, a predetermined excavation is performed. For each length L, it is preferable to provide a tunnel axial force display mechanism 1 at predetermined intervals in the tunnel excavation direction and at predetermined intervals in the tunnel circumferential direction, and excavate while detecting deformation due to the extrusion of the surrounding natural ground 101. . Accordingly, the tunnel excavation work can be performed while accurately detecting the deformation due to the extrusion of the surrounding natural ground 101 at a low cost, and the tunnel can be constructed economically and safely.

  As shown in FIGS. 3 and 4, the tunnel axial force display mechanism 1 according to the first embodiment is connected to a lock bolt 2 driven into a natural ground 101 and a rear end portion of the lock bolt 2. It is comprised from the axial-force display volt | bolt 3 provided so that axial force of 2 may be transmitted.

  As the lock bolt 2, an appropriate lock bolt that can be driven into the ground 101 can be used. In the illustrated example, the entire surface fixing type lock bolt 2 having a male screw portion 21 formed at least at the rear end. It is said that. The coupler 4 is attached to the male screw portion 21 at the rear end portion by screwing a front portion of the coupler 4 having a female screw 41 formed therein. In addition, according to the type of the lock bolt 2 or the like, an appropriate coupler capable of connecting the axial force display bolt 3 and the lock bolt 2 or the like can be used as the coupler in the present invention. The force display bolt 3 can be connected to various lock bolts 2 and the like.

  The axial force display bolt 3 is a full screw bolt in which a male screw portion 311 is formed over the entire length of the outer periphery of the main body 31, and is formed with a short length such as 100 mm. The axial force indication bolt 3 is attached to the coupler 4 by screwing the front end portion of the main body 31 to the rear portion of the coupler 4 attached to the lock bolt 2, and is connected to the rear end portion of the lock bolt 2 through the coupler 4. It has come to be. In the example of FIG. 3 (b), the front part of the coupler 4 and the axial force display bolt 3 screwed into the lock bolt 2 driven into the ground 101 is provided along the inner surface of the ground 101. The lock bolt 2 and the axial force display bolt 3 are driven so as to be disposed in the concrete 102.

  The main body 31 of the axial force indication bolt 3 has a hollow portion 312 that is open to the rear side inside the rear portion, and a mounting hole 313 that extends forward from the approximate center of the hollow portion 312. The shaft portion 321 of the movable pin 32 corresponding to the movable portion is inserted into the mounting hole 313, and the outer peripheral surface of the front portion of the shaft portion 321 is fixed to the inner peripheral surface of the mounting hole 313 via the adhesive layer 35. . Further, the head 322 having a larger diameter than the shaft portion 321 of the movable pin 32 is disposed so as to be accommodated in the hollow portion 312. The rear end surface of the head 322 corresponding to the rear end of the movable pin 32 is a colored display surface 323 colored with a required color.

  When the axial force of the lock bolt 2 is transmitted to the main body 31, the movable pin 32 that is built in the main body 31 and only the shaft portion 321 is fixed to the main body 31 is pulled to the coupler 4 side, that is, the lock bolt 2 side. The parts other than the fixed part move relatively in the axial direction in the main body 31 and the head 322 moves forward in the hollow part 312, that is, toward the front end of the bolt, while the axial force of the lock bolt 2 is reduced. When 31 is not pulled, the parts other than the fixed part move relatively in the axial direction in the main body 31, and the head 322 moves rearward in the hollow portion 312, that is, toward the tunnel space S side.

  A transparent plate 33 is provided on the opening side of the hollow portion 312 located on the rear side of the colored display surface 323 so as to close the hollow portion 312. In the hollow portion 312 closed by the transparent plate 33, a colored fluid enclosure 34 is provided so as to cover the colored display surface 323 and substantially cover the entire head 322 of the movable pin 32. The colored fluid enclosing body 34 is formed by enclosing a colored fluid of a color different from the color of the colored display surface 323 in a transparent bag with high flexibility, and the colored display surface 323 and the transparent plate 33 by the relative movement described above. The thickness covering the colored display surface 323 is set so as to change according to the change in the distance between the two.

  That is, as shown in FIGS. 5 and 6, when the colored fluid enclosure 34 moves relative to the head 322 of the movable pin 32 in the hollow portion 312 toward the front, that is, toward the front end of the bolt, The head 322 is moved between the surface on the shaft portion 321 side of the head portion 322 and the facing surface of the hollow portion 312 facing the head portion 322 so as to flow backward, and the distance between the colored display surface 323 and the transparent plate 33 is increased. A larger portion of the colored fluid enclosure 34 flows into and stays in the larger and wider space. At this time, the color visually recognized from the transparent plate 33 is substantially the same as the color of the colored fluid of the colored fluid enclosure 34.

  When the head 322 of the movable pin 32 moves relative to the rear in the hollow portion 312, that is, toward the tunnel space S, the colored fluid enclosure 34 has the colored display surface 323 and the transparent plate 33. Between the surface of the head portion 322 on the side of the shaft portion 321 and the facing surface of the hollow portion 312 facing the head portion 322. A small portion of the colored fluid enclosing body 34 remains between the colored display surface 323 and the transparent plate 33 which are shortened and the space is narrowed. At this time, the color visually recognized from the transparent plate 33 is substantially the same as the color of the colored display surface 323.

  Further, in the intermediate state between the state in which the color of the colored fluid in the colored fluid enclosure 34 is visually recognized and the state in which the color of the colored display surface 323 is visually recognized, according to the magnitude of the axial force generated in the axial force display bolt 3. The color of the color display surface 323 and the color of the colored fluid enclosure 34 are mixed. 5 indicates the axial force AL generated in the lock bolt 2 and the axial force display bolt 3.

  Further, as shown in FIGS. 3 to 6, a washer 5 is arranged on the outer periphery of the axial force display bolt 3, a nut 6 is screwed from the rear side, and the washer 5 is brought into contact with the inner wall surface 103 of the tunnel. (See FIG. 3B). Since the washer 5 is fitted to the axial force indication bolt 3 by the nut 6, when axial force is generated in the lock bolt 2 in order to resist the pushing force P generated in the ground 101, the coupler 3 is used. The axial force is transmitted to the main body 31 and pulled in the lock bolt direction, whereby the distance between the colored display surface 323 of the movable pin 32 and the transparent plate 33, that is, the colored fluid of the colored fluid enclosure 34 covering the colored display surface 323. The display color changes due to a change in the thickness of the display.

  In the illustrated example, a front side of a cylindrical cap 7 that is formed of a transparent material and has the same inner diameter as that of the male screw portion 311 is externally fitted to the male screw portion 311 that protrudes from the nut 6 of the axial force indication bolt 3. The front side of the cap 7 is fitted to the rear side of the axial force display bolt 3. The cylindrical cap 7 includes a spherical lens 8 that is an extension lens that extends the visible range of the display color from the middle portion to the rear portion, and the spherical lens 8 is close to the rear side of the transparent plate 33. Be placed.

  According to the first embodiment, according to the axial force generated in the lock bolt 2, the thickness of the colored fluid enclosure 34 covering the colored display surface 323 changes and the color seen from the transparent plate 33 changes. The axial force generated in the lock bolt 2 can be recognized by the change of color without looking at. That is, it is excellent in the visibility of the visual confirmation, and it is possible to efficiently confirm the axial force of the lock bolt 2 and detect the ground deformation early.

  In addition, when changing the color visually recognized by a chemical change or a method in which the bag containing the paint ruptures, the color does not return to the original color after being temporarily changed. Then, the color of the colored fluid inclusion body 34 is displayed dark, and once the large axial force generated is reduced, the movable pin 32 returns and the color of the colored display surface 323 is displayed. The axial force can be displayed corresponding to the change.

  In addition, when an axial force display portion is provided on a long lock bolt itself of 3 m to 6 m, etc., it becomes a very expensive lock bolt, whereas an axial force display bolt 3 is provided at the rear end portion of the lock bolt 2. In the connection configuration, it is possible to use a short axial force display bolt 3 with low processing costs, transportation costs, and the like. Furthermore, the axial force display bolt 3 can be used in many cases because the cost is low. It is possible to detect ground deformation more accurately by using many in a wide range. Moreover, the axial force display bolt 3 can be installed as a part of the flow of driving the normal lock bolt 2, and the workability is excellent.

  Further, by connecting the axial force indicating bolt 3 to the rear end portion of the lock bolt 2 via a separate coupler 4, the coupler 4 and the like that can be connected to various existing lock bolts 2 and the like can be used. The force display bolt 3 can be connected to various lock bolts 2 and the like, so that the versatility of the axial force display bolt 3 can be dramatically improved and manufactured by using the same axial force display bolt 3. Cost and construction cost can be greatly reduced.

  In addition, by providing the spherical lens 8 that extends the visible range of the display color, it is possible to visually check the color of the axial force display from various positions, and more reliably visually check the work space in a dark tunnel. The visibility of the axial force display can be further improved.

  Moreover, the spherical lens 8 can be easily attached to the axial force display bolt 3 by installing the spherical lens 8 in the cylindrical cap 7 and fitting the front side of the cylindrical cap 7 to the rear side of the axial force display bolt 3. . Even if the spherical lens 8 is not directly in front of the axial force display bolt 3, it is possible to visually recognize the color of the axial force display from a wider area. However, if the cylindrical cap 7 is made of a transparent material, more It is possible to visually recognize the color of the axial force display from more directions, making it possible to more efficiently check the axial force of the lock bolt 2 and more quickly recognize the change in the display color. Recognize changes in power and understand ground deformation more quickly.

[Axial Force Display Mechanism for Tunnel of Second Embodiment]
Similarly to the first embodiment, the tunnel axial force display mechanism 1a of the second embodiment according to the present invention also has a predetermined interval in the ground 101 in the tunnel space S when, for example, the tunnel is dug for every predetermined excavation length. As shown in FIG. 7, the same lock bolt 2 as that of the first embodiment driven into the natural ground 101 and the rear end portion of the lock bolt 2 are used. It is comprised from the axial force display volt | bolt 3a provided so that it may be connected and the axial force of the lock bolt 2 may be transmitted.

  The axial force display bolt 3a has a male screw portion 311 formed on the outer periphery from the middle portion to the rear portion of the main body 31a, and a coupler portion 36a is integrally provided at the front portion, and a front portion of the coupler portion 36a. An internal thread 361a is formed inside. That is, the coupler-integrated axial force display bolt 3a is obtained by screwing the male screw portion 21 at the rear end portion of the lock bolt 2 and the female screw 361a of the coupler portion 36a so that the axial force display bolt 3a is rearward of the lock bolt 2. It is designed to be connected to the end. The coupler portion 36a of the axial force display bolt 3a connected to the lock bolt 2 driven into the natural ground 101 is disposed in the shotcrete 102 provided along the inner surface of the natural ground 101 in the placement state, for example. (See FIG. 7B).

  As in the first embodiment, the axial force display bolt 3a has a hollow portion 312 and a mounting hole 313 formed in the main body 31a, and a movable pin configured by a shaft portion 321, a head portion 322, and a colored display surface 323. 32 is mounted and fixed in the mounting hole 313 and the hollow portion 312, and the movable pin 32 is relatively movable in the axial direction according to the axial force of the lock bolt 2 transmitted to the main body 31 a, A colored fluid enclosure 34 is provided in the space closed by the transparent plate 33 of the hollow portion 312 so as to cover the colored display surface 323 and substantially cover the entire head 322 of the movable pin 32. The thickness covering the colored display surface 323 can be changed in accordance with the change in the distance between the colored display surface 323 and the transparent plate 33 due to various movements.

  Further, as in the first embodiment, the washer 5 is arranged on the outer periphery of the axial force display bolt 3a, the nut 6 is screwed from the rear side, and the washer 5 is brought into contact with the tunnel inner wall surface 103. Installed. The axial force of the lock bolt 2 that is intended to resist the pushing force P of the natural ground is transmitted to the axial force display bolt 3a, whereby a change in axial force occurs in the axial force display bolt 3a and the display color changes. In the illustrated example, the cylindrical cap 7 in which the spherical lens 8 is housed is not provided. However, as in the first embodiment, the spherical lens 8 is attached to the male screw portion 311 protruding from the nut 6 of the axial force display bolt 3a. It is also possible to provide the spherical lens 8 by fitting the front side of the internal cylindrical cap 7.

  According to the second embodiment, the corresponding effect can be obtained by the configuration corresponding to the first embodiment. Furthermore, by providing the coupler portion 36a integrally with the axial force display bolt 3a, it is possible to reduce the number of components and facilitate component management.

[Axial Force Display Mechanism for Tunnel of Third Embodiment]
Similarly to the first embodiment, the tunnel axial force display mechanism 1b according to the third embodiment of the present invention is provided at predetermined intervals in the ground 101 in the tunnel space S when, for example, the tunnel is dug for every predetermined digging length. As shown in FIG. 8, the same lock bolt 2 as that of the first embodiment driven into the natural ground 101 and the rear end portion of the lock bolt 2 are used. It is comprised from the axial force display volt | bolt 3b provided so that it may be connected and the axial force of the lock bolt 2 may be transmitted.

  The axial force indication bolt 3b has a male screw portion 311 formed on the outer periphery from the middle portion to the front portion of the main body 31b, and a male screw portion is not formed on the rear portion, and a head portion 37b is integrally provided. In other words, the nut-integrated axial force display bolt 3b. As in the first embodiment, the axial force display bolt 3b is configured to screw the male screw portion 311 into the female screw 41 of the coupler 4 to be screwed to the male screw portion 21 at the rear end portion of the lock bolt 2 so that the coupler 4 In this case, the washer 5 is disposed on the outer periphery of the male screw portion 311, and the male screw portion 311 of the axial force display bolt 3 b is screwed into the coupler 4 in this state. Is done.

  And the coupler 4 connected to the rock bolt 2 driven into the natural ground 101 and the front part of the axial force display bolt 3b are, for example, shotcrete 102 provided along the inner surface of the natural ground 101 in the placement state. (See FIG. 8B). Further, the washer 5 is installed so as to be able to abut against the inner wall surface 103 of the tunnel, and the axial force of the lock bolt 2 intended to resist the pushing force P of the natural ground is transmitted to the axial force display bolt 3b. As a result, the axial force is changed in the axial force display bolt 3b, and the display color is changed.

  As in the first embodiment, the axial force display bolt 3b has a hollow portion 312 and a mounting hole 313 formed in the main body 31b, and is composed of a shaft portion 321, a head portion 322, and a colored display surface 323. 32 is mounted and fixed in the mounting hole 313 and the hollow portion 312, and the movable pin 32 is relatively movable in the axial direction according to the axial force of the lock bolt 2 transmitted to the main body 31b. A colored fluid enclosure 34 is provided in the space closed by the transparent plate 33 of the hollow portion 312 so as to cover the colored display surface 323 and substantially cover the entire head 322 of the movable pin 32. The thickness covering the colored display surface 323 can be changed in accordance with the change in the distance between the colored display surface 323 and the transparent plate 33 due to various movements.

  According to the third embodiment, the corresponding effect can be obtained by the configuration corresponding to the first embodiment. Furthermore, by providing the head portion 37b integrally with the axial force display bolt 3a, it is possible to reduce the number of components and facilitate component management.

[Modifications of Embodiment, etc.]
In addition to each invention and each embodiment, the invention disclosed in this specification is specified by changing these partial configurations to other configurations disclosed in this specification within the applicable range, or these It includes those specified by adding other configurations disclosed in this specification to the configuration, or those obtained by deleting these partial configurations to the extent that partial effects can be obtained and specifying them as a superordinate concept. The following modifications are also included.

  For example, the expansion lens according to the present invention is not limited to the above spherical lens as long as it can expand the visible range of the display color. For example, the display color of the colored display surface is enlarged so that it can be viewed from a distance. It is possible to use a magnifying lens, a hemispherical magnifying lens, a polygonal lens that makes the display color of the colored display surface visible from multiple directions, or the like.

  Further, the configuration in which the extended lens such as the spherical lens 8 is installed on the rear side of the transparent plate 33 is appropriate in addition to the external fitting to the male screw portion 311 on the front side of the cylindrical cap 8. A configuration in which the extension lens is installed using an instrument that holds the outer peripheral edge of the extension lens and has a fitting portion that can be fitted to the head portion 37b of the axial force display bolt 3b of the third embodiment at the front portion. Is possible.

  In addition, the movable portion in the present invention has a colored display surface at the rear end, and is internally mounted in the main body so as to move relatively in the axial direction according to the axial force of the lock bolt transmitted to the main body. As long as the thickness of the colored fluid enclosing body covering the surface is provided so as to be variable, the thickness is not limited to the movable pin 32 of the above embodiment.

  In addition, the colored fluid enclosure in the present invention is appropriate as long as a colored fluid of a color different from that of the colored display surface is visibly enclosed, and the color of the colored fluid is different from the color of the colored display surface. However, it is preferable to use a combination of colors that can clearly recognize the color difference, such as making the two colors have a large color difference.

  The present invention can be used, for example, when displaying the axial force of a rock bolt for supporting a tunnel so that it can be visually confirmed.

DESCRIPTION OF SYMBOLS 1, 1a, 1b ... Tunnel axial force display mechanism 2 ... Lock bolt 21 ... Male screw part 3, 3a, 3b ... Axial force display bolt 31, 31a, 31b ... Main body 311 ... Male screw part 312 ... Hollow part 313 ... Mounting hole 32 ... movable pin 321 ... shaft part 322 ... head 323 ... colored display surface 33 ... transparent plate 34 ... colored fluid inclusion body 35 ... adhesive layer 36a ... coupler part 361a ... female screw 37b ... head 4 ... coupler 41 ... female screw 5 ... washer 6 ... nut 7 ... cylindrical cap 8 ... spherical lens 101 ... ground mountain 102 ... sprayed concrete 103 ... tunnel inner wall surface 104 ... ground mountain arch 105 ... face 106 ... lining concrete S ... tunnel space L ... digging length P ... extrusion Force AL ... Axial force

Claims (6)

A lock bolt that is driven into a natural ground, and an axial force display bolt that is connected to a rear end portion of the lock bolt and is provided so that an axial force of the lock bolt is transmitted,
The axial force display bolt has a main body and a colored display surface at the rear end, and a shaft corresponding to the axial force of the lock bolt generated against the pushing force generated on the ground transmitted to the main body. A movable part built in the main body so as to move relative to the direction, a transparent plate provided on the rear side of the colored display surface, and a colored fluid having a color different from that of the colored display surface are visibly enclosed. The color display surface is provided so as to cover the color display surface, and the thickness covering the color display surface is changeable according to a change in the distance between the color display surface and the transparent plate due to the relative movement. An axial force display mechanism for a tunnel characterized by comprising a colored fluid enclosure.   2. The axial force display mechanism for a tunnel according to claim 1, wherein the axial force display bolt is connected to a rear end portion of the lock bolt via a separate coupler.   3. The tunnel axial force display mechanism according to claim 1, wherein an extension lens is provided on the rear side of the transparent plate to extend a visible color range. The expansion lens is a spherical lens;
4. The axial force display mechanism for a tunnel according to claim 3, wherein the spherical lens is mounted in a cylindrical cap, and a front side of the cylindrical cap is fitted to a rear side of the axial force display bolt. It is connected to the rear end portion of the lock bolt driven into the natural ground, and is an axial force indication bolt for tunnel for detecting natural ground deformation provided to transmit the axial force of the lock bolt,
The main body has a colored display surface at the rear end, and moves relatively in the axial direction according to the axial force of the lock bolt generated against the pushing force generated in the ground transmitted to the main body. As described above, the movable part built in the main body, a transparent plate provided on the rear side of the colored display surface, and a colored fluid having a color different from that of the colored display surface are visibly enclosed, and covers the colored display surface And a colored fluid enclosure that is installed so that the thickness covering the colored display surface can be changed in accordance with a change in the distance between the colored display surface and the transparent plate due to the relative movement. Axial force indicating bolt for tunnels, characterized by comprising.   The tunnel axial force display mechanism according to any one of claims 1 to 4 is provided at every predetermined interval in the tunnel excavation direction and every predetermined interval in the tunnel circumferential direction for each predetermined excavation length of the tunnel, A tunnel excavation method characterized by excavating a tunnel while detecting deformation due to extrusion of surrounding ground with a display mechanism.

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