JP6285306B2 - Ground anchor tension change display device - Google Patents

Description

  In the present invention, when the tension force of the tendon material is changed in the use state of the ground anchor embedded in the ground in a state where the tension force is applied to the tendon material, the change state can be recognized on the ground surface. The present invention relates to a tension fluctuation display device for a ground anchor.

  In the ground anchor, the anchor body connected to the tip of the tension material on the ground side is fixed in the ground, and the head fixing body connected to the head on the ground surface side of the tension material is fixed on the ground surface. By applying tension to the tension material, it exerts a compressive force from the ground surface and the ground to stabilize the ground against collapse.

  The anchor body is fixed to the fixed layer in the ground, but the ground surface on which the head fixing member is fixed is the surface of the moving layer that may move relative to the fixed layer. There is a possibility that the tension force of the tendon will fluctuate due to slipping on the sliding surface which is the boundary surface between the tension material and the like. If the tension of the tension material fluctuates and the tension force decreases, the stabilization effect on the ground is lost, and if the tension force increases, there is a risk that the tension material will break. However, since it is necessary to adjust the tension, it is necessary to check whether the tension varies.

  As a method of confirming the fluctuation of the tension force, there are a method of measuring expansion / contraction or displacement of the tension material exposed from the ground surface (see Patent Documents 1 to 4), a method of measuring the tension force (see Patent Document 5), and the like. However, these methods have the inconvenience that it is difficult to intuitively judge the fluctuation of the tension of the tendon from the appearance because it is necessary to judge whether the tendon is in the stretched state or the contracted state from the numerical value as the measurement result. .

  On the other hand, as a method of confirming the magnitude (change) of the tension force of the tension material directly by visually observing the head fixing body of the tension material, it is connected to the head of the tension material, and the amount of expansion and contraction of the tension material is adjusted. There is a method in which light emitters having different colors are caused to emit light (see Patent Document 6).

JP-A-11-63972 (Claim 1, paragraphs 0011 to 0014, FIG. 1) JP 2002-81061 A (Claim 1, paragraphs 0008 to 0012, FIGS. 1 to 5) JP 2003-247232 A (Claim 1, paragraphs 0024 to 0030, FIGS. 1 to 6) JP 2009-293325 A (paragraphs 0014 to 0024, FIGS. 1 to 8) JP 2000-46662 A (Claim 1, paragraphs 0013 to 0044, FIG. 1) JP-A-8-144273 (Claim 1, paragraphs 0025 to 0048, FIGS. 1 to 8)

  In Patent Document 6, a light-emitting display unit having a plurality of different color displays and a power source unit are connected to a part of the head fixing body exposed on the ground surface, and any one corresponding to a tension in a preset range is selected. Since the display device emits light, there is an advantage that the magnitude (change) of the tension force can be known visually on the ground surface side.

  However, since the light emission of the display depends on the supply of electric power from the power supply unit, it is necessary to use a storage battery in combination to prevent the supply of electric power from being interrupted (paragraph 0027), and the tension of the tension material is large. Accordingly, since it is necessary to control the light-emitting display unit for causing any one of the plurality of displays to emit light (paragraphs 0031 to 0033), there are many equipments installed around the head fixing body. Therefore, there is a drawback that the cost required for the equipment becomes high. In addition, when solar cells are used as the power source, for example, when there is a shortage of sunshine, the power supply may be interrupted when the storage battery power is consumed (paragraph 0027), and the function may stop. I can't say it isn't.

  From the above background, the present invention has a simple configuration that does not require a power source, but the tension force of the ground anchor that can immediately grasp the tension state of the tension material only by visually observing the vicinity of the head fixing body of the tension material. A variable display device is proposed.

The tension anchor fluctuation display device of the ground anchor according to the first aspect of the present invention is connected to a tension material embedded in the ground in a state where a tension force is applied, and a ground-side tip portion of the tension material, In a ground anchor provided with an anchor body fixed inside and a head fixing body connected to the ground surface side head of the tendon material and fixed on the ground surface in a state exposed to the ground surface,
It is constructed between the anchor body and the head fixing body, and is directly or indirectly connected to the anchor body at the end on the anchor body side, and the head fixing body at the end on the head fixing body side. Directly or indirectly connected to a spring directly or indirectly connected to a spring, and directly or indirectly supported by the head fixing body in a freely rotatable manner, in conjunction with expansion and contraction of the tension material A rotating body that rotates ,
A tension transmission member is connected to the end of the cable on the spring side, the spring is connected to the other end of the tension transmission member, and the rotating body is in contact with or meshing with the tension transmission member. This is a component requirement.

“The cable is directly or indirectly connected to the anchor body” at the end of the anchor body side means that the cable is directly connected to the anchor body, and that the cable is connected to the anchor body 12 as shown in FIG. It may be connected to a connecting member 19 such as a bolt . Cable 2 is "directly to the spring that is connected to the head fixing member, or indirectly connected" at the end of the head fixing member 13 side to the cable 2 is connected to the spring 4 chains and belts, etc. It says that that will be connected to the tension transmission member 5. “The spring is directly or indirectly connected to the head fixing body” means that the spring 4 is directly connected to the head fixing body 13 and the head fixing body 13 is fixed as shown in the figure, for example. The spring 4 may be connected to the case 6 that is connected (joined) to the fixing plate 16 and is integrally joined to the tip (upper end) of the cap 18 that covers the head fixing body 13. In the drawing, the spring 4 is connected to a bottom plate 61 which is a part of the case 6.

  “The rotating body is directly or indirectly rotatably supported by the head fixing body” means that the rotating body 3 is directly and rotatably supported by the head fixing body 13 as illustrated. For example, it means that it is rotatably supported by any part of the case 6 joined to the head fixing body 13. In the drawing, the rotating body 3 is rotatably supported (axially supported) on a support member 7 that is a part of the case 6 or a support plate 71 that is a part of the support member 7.

  Since the spring 4 bears the tension to be applied to the cable 2, a coil spring that exhibits a restoring force in the axial direction is suitable for the spring 2, but depending on the method of use, a spring such as a leaf spring or a disc spring may be used. The form of the spring 4 is not questioned.

  As shown in FIG. 1- (a), when the tension member 11 is given an initial tension force, the spring 4 causes the cable 2 to be restored by a restoring force in a normal state in which the tension material 11 is not further extended or contracted from the installed state in the ground. The cable 2 is in a state of being pulled toward the spring 4 (neutral state), and the cable 2 is balanced with the elastic spring 4. At this time, the cable 2 is connected to the anchor body 12 at the end on the anchor body 12 side in a state of being laid between the anchor body 12 and the head fixing body 13 and is also connected to the spring 4 while being balanced with the spring 4. Therefore, if expansion and contraction occurs in the tendon material 11, the section existing in the ground of the cable 2 follows the tendon material 11, and accordingly, the length of the section protruding from the ground of the cable 2 is expanded or contracted. (Change.

  The cable 2 and the tendon material 11 are buried in the ground (grout material 15) in a state where the adhesion with the periphery (the grout material 15) of the ground is cut so as to follow the expansion and contraction of the tendon material 11. For this reason, as a result of the ground surface moving with respect to the anchor body 12 due to subsidence, bulging, etc., in the section of the cable 2 existing in the ground, the end on the anchor body 12 side (connection to the anchor body 12) The portion) moves relative to the ground surface (fixing plate 16) with the anchor body 12 in the axial direction of the tension material 11, thereby following the expansion and contraction generated in the tension material 11.

  Since the cable 2 is in a state of being pulled toward the ground surface from the spring 4 over the entire length of the section existing in the ground and the section protruding from the ground, the length of the section of the cable 2 protruding from the ground is the moving layer. It changes with the fluctuation (movement) to the non-moving layer. Since the cable 2 itself does not basically expand and contract, as shown in FIG. 1- (b), if the length of the section protruding from the ground of the cable 2 is increased, the spring 4 contracts and is shown in (c). Thus, if the length of the section which protruded from the underground of the cable 2 becomes small, the spring 4 will expand | extend.

  As shown in FIG. 1- (c), when the ground surface is moved away from the anchor body 12 side due to a bump or the like, the end of the cable 2 on the anchor body 12 side follows the anchor body 12 and the ground surface. It moves relative to the surface (fixed plate 16) in a direction away from the ground surface. As shown in (b), when the ground surface moves to the anchor body 12 side due to subsidence or the like, the end of the cable 2 on the anchor body 12 side is attracted to the spring 4 to follow the anchor body 12. It moves relative to the ground surface in a direction approaching the ground surface. As described above, the section existing in the ground of the cable 2 follows the expansion and contraction of the tension material 11. The section projecting from the ground of the cable 2 is relative to the fixing plate 16 and the head fixing body 13 in the axial direction. That is, the length of the section protruding from the ground of the cable 2 is changed.

  The rotation of “the rotating body rotates in conjunction with the expansion and contraction of the tension material” in claim 1 is caused by the expansion and contraction of the tension material 11 as shown in FIG. 1- (b) or (c). As a result of the section protruding from the inside moving in the axial direction with respect to the fixing plate 16 (and the head fixing body 13), the rotating body 3 is supported around or around the support shaft 3a which is the rotation axis (center of rotation). It means rotating together with the shaft 3a in either positive or negative direction with respect to the case 6 (head fixing body 13). 3 and 4 show specific examples in the case where the rotating body 3 rotates with respect to the case 6 together with the support shaft 3a.

  In the normal state (neutral state of the spring 4) shown in FIG. 1- (a), the end of the cable 2 on the spring 4 side is in a state of being pulled toward the connecting portion (bottom plate 61) side to the case 6 (neutral state). The rotating body 3 that is interlocked with the axial movement of the cable 2 relative to the fixing plate 16 (extension and contraction of the tension member 11) is not rotated to any side from the neutral position. The state in which the rotating body 3 is not rotated from the neutral position is a state in which the cable 2 has not moved in the axial direction from the neutral state of the tendon 11, and the cable 2 maintains a balance with the restoring force of the spring 4. 2 has a tension that balances the restoring force applied to the spring 4 in the initial state.

  Since the anchor body 12 is fixed to the immovable layer in the ground as described above and the head fixing body 13 is fixed to the ground surface (fixed plate 16) which is the surface of the moving layer, the groundwater level changes, the ground subsidence, etc. When the moving layer slips with respect to the non-moving layer due to the above, a change occurs in the tension force of the tension member 11 installed between the anchor body 12 and the head fixing body 13. A change (change amount) in the tension force of the tension material 11 appears as expansion / contraction (expansion / contraction amount) of the tension material 11.

  If the tension material 11 contracts due to the ground surface moving to the immobile layer side as shown in FIG. 1- (b), the distance from the ground surface to the anchor body 12 is shortened, so that the cable 2 Since the section which exists in becomes short and the section which protrudes from underground becomes long, the spring 4 connected to the cable 2 contracts with a restoring force. On the other hand, as shown in (c), if the tension material 11 expands due to the ground surface moving to the side opposite to the stationary layer (away from the stationary layer) or the like, the distance from the ground surface to the anchor body 12 is increased. Since the section of the cable 2 existing in the ground becomes longer and the section protruding from the ground becomes shorter, the spring 4 connected to the cable 2 is drawn toward the ground surface side and extends.

  As shown in FIG. 1- (b), when the distance between the anchor body 12 and the head fixing body 13 decreases due to the contraction of the tension material 11, the tension material 11 is more relaxed than when it is in the neutral state (initial state). For this reason, the tension of the tendon 11 is lowered from the initial state. At this time, as the anchor body 12 approaches the ground surface, the section protruding from the ground surface of the cable 2 to the ground becomes long. As a result, the spring 4 is contracted from the initial state (neutral state) by its own restoring force. Therefore, the rotating body 3 rotates to the spring 4 side. Since the rotation of the rotating body 3 toward the spring 4 occurs when the tension of the tension member 11 decreases, the rotation body 3 at this time displays a decrease in the tension of the tension member 11.

  As shown in FIG. 1- (c), when the distance between the anchor body 12 and the head fixing body 13 increases due to the extension of the tension material 11, the tension material 11 is more tensioned than when the tension material 11 is in the neutral state. 11 tension rises from the initial state. At this time, as the anchor body 12 moves away from the ground surface, the section protruding from the ground surface of the cable 2 to the ground is shortened. As a result, the spring 4 receives a tensile force from the cable 2 from the initial state (neutral state), and is in an extended state. Therefore, the rotating body 3 rotates to the cable 2 side. Since the rotation of the rotator 3 toward the cable 2 occurs when the tension of the tension member 11 increases, the rotator 3 at this time displays an increase in the tension of the tension member 11. From the situation of FIGS. 1- (b) and (c), the rotating body 3 eventually rotates in conjunction with the expansion and contraction of the tension material 11, and either positive or negative direction indicating either the extension or contraction of the tension material 11 Rotate to.

  Since the rotating body 3 functions to display the fluctuation of the tension force of the tension member 11 by rotating in the positive or negative direction from the neutral position, that is, in either direction of the cable 2 side or the spring 4 side, it is tensioned from the neutral position. It is necessary to rotate in the positive and negative directions in conjunction with the expansion and contraction of the spring 4 accompanying the change in the distance between the ground surface and the anchor body 12 due to the expansion and contraction of the material 11. In this relationship, since the spring 4 needs to extend from the natural length state at the neutral position of the rotating body 3 so that the spring 4 can contract from the neutral position of the rotating body 3, In a normal state (neutral state) in which no expansion or contraction occurs, the spring 4 extends and is placed in a state where a restoring force is exhibited. In a state where the spring 4 is extended in a normal state and a restoring force is exerted, as described above, a tension corresponding to the restoring force of the spring 4 is applied to the cable 2 which balances the spring 4 in a normal state. is there.

In the normal state of the tension material 11, the rotating body 3 is not rotated from the neutral position. From this state, the section existing in the ground of the cable 2 expands and contracts with the expansion and contraction of the tension material 11, and the spring 4 By expanding and contracting, the rotating body 3 rotates in either positive or negative direction. As described above, if the tension member 11 contracts due to the fluctuation of the ground surface or the like, the spring 4 contracts. As a result, the rotating body 3 rotates to the spring 4 side. As a result of the expansion, the rotating body 3 rotates to the cable 2 side, and thus the positive and negative directions of the rotating body 3 indicate, for example, the direction of extension (+) and the direction of contraction (−) of the tension material 11, respectively. From this relationship, as shown in FIG. 1, by displaying a positive or negative sign in the direction of rotation of the rotating body 3, the tension material 11 is immediately in an expanded state or in a contracted state from the rotation state of the rotating body 3. It will be determined if there is. In particular, whether the rotating body 3 is rotating in a positive or negative direction according to the expansion and contraction of the tension material 11 is determined when the display needle 8 (claim 2 ) described later is integrated with the rotating body 3. Since the tip can display the rotation angle θ of the rotating body 3 in an enlarged manner, the observer can easily recognize it.

  In the initial state of the tension material 11, it is not always necessary to apply tension to the cable 2, but the cable 2 follows the expansion and contraction of the tension material 11, and the section existing in the ground expands and contracts. In order to improve the reactivity to expansion / contraction from the state (normal state), it is appropriate that a certain amount of tension is applied, and this initial tension is the amount of elongation from the natural length of the spring 4 as described above. Is given as a restoring force of the spring 4. Because the cable 2 and the spring 4 pass through the rotating body 3, the tension of the cable 2 and the restoring force of the spring 4 are always balanced and kept in balance, regardless of the change in the tension force of the tension member 11. When the tension material 11 contracts from the normal state and the tension force of the tension material 11 decreases, the spring 4 also contracts and the restoring force decreases. When the tension material 11 is extended from the normal time and the tension force of the tension material 11 is increased, the spring 4 is also extended and the restoring force is increased.

  As shown in FIG. 1, the cable 2 is disposed in the ground in a state parallel to or close to the tension material 11, and is folded at the position of the rotating body 3 in the section protruding from the ground or via the rotating body 3. Then, since it is connected to the spring 4 connected to any part of the head fixing body 13 or the like, the support shaft 3a which is the rotating shaft of the rotating body 3 with which the cable 2 comes into contact is the axial direction of the tension material 11 It faces in any direction in the plane orthogonal to “The cable is connected to the spring via the rotating body” means that the cable 2 (including the tension transmission member 5) is a straight line parallel to the axis of the tension member 11 in the section on both sides of the rotating body 3. The angles α and β between the two sections are arbitrary, for example, as shown in FIG. 1- (a), the angles α and β formed between the two side sections are equal or nearly equal, and an acute angle close to 0 °, This means that the angle β formed by the section on the spring 4 side via 3 may be a right angle or an obtuse angle.

  The angles α and β formed by the sections on both sides of the cable 2 with the rotating body 3 sandwiched between the case 4 in which the rotating body 3 is accommodated in the head fixing body 13 are attached to the case 6 of the spring 4. It is determined by the connection position and the position of the insertion hole 61a formed in a part of the case 6 through which the cable 2 is inserted. The position of the insertion hole 61a of the case 6 is determined by the position of the insertion hole 16a through which the cable 2 is inserted when the cable 2 does not bypass the fixing plate 16. The insertion hole 61a of the case 6 is as shown in FIG. 2 may be positioned on a straight line connecting the center O of the rotating body 3 and the insertion hole 16a of the fixing plate 16, or may not be as shown in FIG.

  In particular, when the cable 2 is folded back at the position of the rotating body 3 and is connected to the spring 4 of the case 6 as shown in the figure, the angles α and β formed by the sections on both sides of the cable 2 with the rotating body 3 interposed therebetween. In this case, the spring 4 and the cable 2 can be positioned symmetrically with respect to a straight line passing through the center O of the rotating body 3 and parallel to the axis of the tendon 11. “A straight line parallel to the axis of the tendon 11” means that the straight line passing through the center O of the rotating body 3 is located on the axis of the tendon 11 as shown, and on a line deviated from the axis of the tendon 11 Say that it may be located.

  In this case, in contrast to the case where the cable 2 is not folded back at the position of the rotating body 3 (when α and β are different), the cable 2 or the tension transmission member 5 that is a part of the cable 2 is applied to the rotating body 3. Since the winding section (winding angle) can be made large, the effect of transmitting tension between the cable 2 and the rotating body 3 is enhanced, and the cable 2 is less likely to slip with respect to the rotating body 3. Is possible. Moreover, since the cable 2 folds the rotating body 3, the width of the region surrounding the spring 4 and the cable 2 can be suppressed in the case 6 integrated with the head fixing body 13 as shown in the figure. Including the extended state, the spring 4 and the cable 2 can always be accommodated in the case 6 having a limited volume, and exposure of the spring 4 and the cable 2 to the outside air can be easily avoided.

The rotating body 3 displays the change (change amount) of the tension material 11 by rotating around the support shaft 3a or around the center of the support shaft 3a. However, the larger the radius r of the rotating body 3 shown in FIG. The radius r of the rotating body 3 is set to be larger, or the indicator needle 8 having a length larger than the radius r of the rotating body 3 (the distance from the center of the rotating body 3 to the tip is large) is integrated with the rotating body 3. (claim 2) by reduction, it is possible to display an enlarged variation of the tension of the cable 2. In the latter case, the rotation angle θ of the rotating body 3 is enlarged to a movement amount (= circumferential length (θ × R)) that is R times the length of the display needle 8, so that a slight rotation (rotation angle) of the rotating body 3 occurs. θ) is easily reflected in the movement of the tip of the display needle 8, so that there is an effect of improving the visibility to the observer. As described above, the support shaft 3a of the rotator 3 faces in an arbitrary direction in a plane orthogonal to the axial direction of the tendon 11, but the support shaft 3a of the rotator 3 is the observer when appealing to the observer's vision. Directed to the side.

  As described above, in the present invention, the amount of change in tension of the tension member 11 can be displayed as the amount of rotation (rotation angle θ) of the rotating body 3 that rotates in conjunction with the expansion and contraction of the tension member 11, so a power source is required. Although it is a simple configuration that does not, the state (change) of the tension force of the tension member 11 is immediately grasped only by observing the rotation angle of the rotary member 3 disposed on the head fixing body 13 side of the tension member 11. It becomes possible. In particular, when the display needle 8 is integrated with the rotary body 3, the display needle 8 displays the rotation angle θ of the rotary body 3 by enlarging the circumference (θ × R) that is R times the length of the display needle 8. Therefore, it is possible to improve the visibility to the observer.

  The tension fluctuation display device 1 is connected to the head fixing body 13 protruding from the ground surface of the ground anchor 10 and is installed on the ground together with the section protruding from the ground surface of the cable 2. Is installed on the slope, even if the tension fluctuation display device 1 is damaged or flows out due to the occurrence of falling rocks from above, the section existing in the ground of the cable 2 is kept healthy. Therefore, the tension fluctuation display device 1 can be easily re-installed or restored.

  In a section where the cable 2 passes through the head fixing body 13, the cable 2 is inserted through an insertion hole 16 a formed in any part of the fixing plate 16 to which the head fixing body 13 is fixed or an insertion hole of a connected component. By doing so, or by detouring the fixing plate 16, it is exposed from the ground to the ground surface. Exposing means that the cable 2 protrudes from the ground surface to the outside of the ground, and is not necessarily exposed to the outside air, but may be housed in the case 6 integrated with the head fixing body 13 as shown in the figure. It is a purpose. The cable 2 is preferably not in contact with the fixing plate 16 in order to prevent or suppress wear in the use state. However, even if the frictional force with the cable 2 is generated by the contact, the influence on the movement of the cable 2 Since this does not affect the rotation of the rotating body 3, it is allowed to contact any part of the fixing plate 16. When the cable 2 comes into contact with the fixing plate 16 (insertion hole 16a), the cable 2 is brought into contact with a low friction material for reducing wear as necessary.

  The cable 2 is installed between the anchor body 12 and the head fixing body 13 (case 6), and is tensioned by being connected to the spring 4, so that the tension is maintained while maintaining the restoring force of the spring 4 and the balance. In order to follow the expansion and contraction of the material 11, the movement amount ΔL1 of the section protruding from the ground surface of the cable 2 (the section protruding to the ground), that is, the amount of expansion and contraction of the spring 4 from the normal time is the tension of the tension material 11. It will show the increase or decrease of force. Since the movement of the section protruding from the ground surface of the cable 2 occurs as the tension material 11 expands and contracts, if the cable 2 does not expand and contract, the movement amount of the section protruding from the ground surface of the cable 2 (the amount of expansion and contraction of the spring 4) ) ΔL1 is equal to the amount of expansion / contraction ΔL0 of the tendon 11 from the installed state.

The drawing shows an example in which a sprocket is used for the rotating body 3 as shown in FIG. 3 and a chain is connected to a section engaging with the rotating body 3 in the entire length of the cable 2. A pulley, a roller, a gear, or the like is also used, and a belt, a tooth profile belt, or the like is also used in a partial section of the cable 2 according to the form of the rotating body 3. The connection of a chain, belt, or the like to the section of the cable 2 that meshes with the rotating body 3 is an example of the fact that the tension transmission member 5 is connected to the end of the cable 2 on the spring 4 side (Claim 1 ). It hits.

Cable 2, the coupled the tension transmission member 5 in a section meshing with at least the rotary body 3 Rukoto (claim 1), without a tension transmission member 5 and the rotor 3 is caused to slip from each other, contact or meshing Therefore, there is an advantage that the expansion and contraction of the cable 2 can be reliably transmitted to the rotation of the rotating body.

  Here, as shown in FIG. 3, if the distance from the center O of the rotating body 3 to the cable 2 (the center in the thickness direction) (radius of the rotating body) is r, the amount of movement of the cable 2 (the spring 4) Since the expansion / contraction amount ΔL1 is the circumferential length (rotation amount) of the rotating body 3, the rotation angle Δθ (radian) of the rotating body 3 and the movement amount ΔL1 of the cable 2 have a relationship of ΔL1 = r · Δθ. From this relationship, the smaller the radius r of the rotating body 3, that is, the distance from the center of the rotating body 3 to the contact surface of the cable 2, the larger the rotation angle Δθ of the rotating body 3, and the moving amount ΔL 1 of the cable 2 becomes the rotating body. It becomes easy to be reflected in the rotation angle Δθ of 3, and it becomes easy to appeal to the eye.

  Therefore, when the display needle 8 is integrated with the rotating body 3, the amount of movement ΔL1 of the cable 2 is increased as the distance R to the tip of the display needle 8 is increased while the radius r of the rotating body 3 is decreased. Can be enlarged and displayed on the rotation amount (periphery) of the display needle 8 after being enlarged to the rotation angle Δθ of the rotator 3, so that the recognition effect on the observer can be enhanced.

  Further, as described above, since the movement amount ΔL1 of the cable 2 is also the expansion / contraction amount ΔL0 of the tension material 11, the expansion / contraction amount with respect to the original length of the tension material 11 (natural length where no tension is applied and expansion / contraction does not occur) L0. From the ratio ΔL0 / L0 (= ε: degree of strain = σ / E) of ΔL0, the amount of change in tension ΔT0 of the tendon material 11 is calculated using the cross-sectional area A0 and the elastic modulus E0 of the tendon material ΔT0 = E0 · A0 · ( Since it is expressed as (ΔL0 / L0), it is possible to calculate the change amount ΔT0 of the tension force of the tension member 11 directly from the moving amount of the cable 2 (the amount of expansion / contraction of the spring 4) ΔL1 (= ΔL0).

  A tension anchor fluctuation display device for a ground anchor is installed in parallel with a tension member between an anchor body and a head fixing body, a spring connected to the head fixing body, a cable connected to the anchor body, and a head Since it is composed of a rotating body that is connected to the fixing body and rotates in conjunction with the expansion and contraction of the tension material, the amount of change in tension of the tension material corresponding to the expansion and contraction amount of the tension material It can be displayed as a rotation amount (rotation angle). Therefore, it is possible to immediately grasp the tension force state of the tension member only by observing the rotation angle of the rotating member arranged on the head fixing body side of the tension member, while having a simple configuration that does not require a power source. is there.

(A) is a longitudinal sectional view showing a normal state in which the tension material constituting the ground anchor is buried in the ground in a state where tension is applied, and the tension material does not expand and contract from the state. b) is a longitudinal sectional view showing the state when the ground surface is moved from the state of (a) to the immobile layer and the tension of the tendon is reduced, and (c) is the state of the ground surface from the state of (a). It is the longitudinal cross-sectional view which showed a mode when it moved to the other side of a fixed layer and the tension | tensile_strength of the tension material rose. When the tension force of the tension material is reduced, the ground anchor cable shown in FIG. 1 is passed through the outer peripheral side of the cap of the head fixing body and the fixing plate of the head fixing body is penetrated and placed in the ground. It is the longitudinal cross-sectional view shown as a mode. It is the elevation view which showed a mode that the tension transmission member connected to the edge part by the side of the spring of a cable was wound around the rotary body, and was connected to the spring. It is the xx sectional view taken on the line of FIG. It is the elevation which showed a mode that the indicator needle was integrated with the rotary body, and it has been arrange | positioned on the front surface side of the display board on an elevation surface. It is the elevation which showed a mode that the ratio with the original state of the cable movement amount (stretching material expansion-contraction amount) corresponding to the rotation angle of a display needle (rotating body) was displayed on the display board. It is the perspective view which showed the installation state to the ground of the ground anchor, and the fixation state to the ground surface of a head fixing body.

  FIG. 1- (a) shows a tension material 11 embedded in the ground in a state where tension is applied, an anchor body 12 connected to the ground-side tip of the tension material 11 and fixed in the ground, Displays the fluctuation state of the tension force of the tension material 11 of the ground anchor 10 provided with the head fixing body 13 connected to the ground surface side head of the tension material 11 and fixed to the ground surface while being exposed to the ground surface. The structural example of the tension | tensile_strength fluctuation | variation display apparatus 1 to perform is shown. FIG. 1- (a) shows a neutral situation in which the tension material 11 is fixed with a tension force and the tension force does not fluctuate.

  The tension force fluctuation display device 1 is installed between the anchor body 12 and the head fixing body 13, and is directly or indirectly connected to the anchor body 12 at the end on the anchor body 12 side. The cable 2 connected directly or indirectly to the spring 4 directly or indirectly connected to the head fixing body 13 and the head fixing body 13 are directly or indirectly supported rotatably at the end of the head. The rotating body 3 that rotates in conjunction with the expansion and contraction of the tension material 11 is provided as a basic component.

  “The cable 2 is indirectly connected to the anchor body 12” means that the cable 2 is connected to a connecting member 19 such as a screw (eye bolt) directly connected to the anchor body 12 or the tension member 11 as illustrated. Say that. “The spring 4 is indirectly connected to the head fixing body 13” means that any part (the bottom plate 61) constituting the case 6 joined in series to the tip of the head fixing body 13 as shown in the figure. ) Is connected to the spring 4.

  “The cable 2 is indirectly connected to the spring 4” means that the section of the cable 2 that contacts the rotating body 3 is replaced with a tension transmission member 5 such as a chain as shown in the figure. It means that one end is connected to the spring 4. “Directly connected” means that the cable 2 is directly connected to the spring 4 without the tension transmission member 5 being connected to the cable 2. “The rotating body 3 is indirectly supported by the head fixing body 13” means that any part (support material 7 (support plate 71)) of the case 6 joined to the head fixing body 13 is supported. It says that the rotary body 3 is supported.

  After the anchor body 12 and the tension member 11 of the ground anchor 10 form a drill hole 14 in the ground up to the installation depth of the anchor body 12, for example, a grout material 15 for fixing the anchor body 12 is filled in the drill hole 14. , Inserted into the grout material 15. The anchor body 12 is made to reach a depth that allows the entire length of the anchor body 12 to be buried in a fixed layer in the ground. The grout material 15 is filled into the hole 14 in a state where a casing is inserted on the inner peripheral side of the hole 14 in order to prevent the ground from collapsing and to prevent the grout 15 from penetrating into the ground. After filling the grout material 15, the casing is recovered. The anchor body 12 is fixed in the ground by the hardening of the grout material 15, and the tension force can be introduced into the tension material 11.

  After the filling of the grout material 15, a fixing plate 16 for fixing the head fixing body 13 is installed or constructed on the ground surface as shown in FIGS. Thereafter, a tension force is introduced into the tension material 11, and a compressive force is applied from the fixing plate 16 to the ground in the axial direction of the tension material 11. FIG. 7 shows a state in which the anchor body 12 of the ground anchor 10 is fixed in the ground, and the head fixing body 13 is fixed on the fixing plate 16. In FIG. 7, the fixing plate 16 is not a ground surface, but is a block-like or frame-like protection block 20 that is installed or constructed on the ground surface (slope) to protect the ground surface (slope) or prevent collapse. It is fixed on the surface.

  After the tension force is introduced to the tension material 11, the head fixing body 13, which is an end portion protruding from the ground surface of the tension material 11, is fixed to the fixing plate 16 by a fixing material 17 such as a nut. The front end portion of the tension member 11 on the head fixing body 13 side and the fixing material 17 are accommodated in a cap 18 fixed to the surface side of the fixing plate 16 and are protected from rainwater and outside air. As shown in the drawing, when the cable 2 is arranged in the grout material 15 without bypassing the fixing plate 16, an insertion hole 16 a for inserting the cable 2 is formed in the fixing plate 16.

  The tendon material 11 is inserted into the sheath or coated with grease so that the tendon material 11 can freely expand and contract in accordance with the change of the ground surface (movement of the moving layer) in the hardened grout material 15. And the ground (grouting material 15) are inserted into the grout material 15 in a state where the adhesion between the ground and the ground (grouting material 15) is cut. The loss of tension due to the attachment of the tension material 11 and the ground is prevented by the adhesion between the tension material 11 and the ground being cut.

  The cable 2 attached to the tension material 11 is also inserted into the sheath or applied with grease so that the cable 2 can move with respect to the grout material 15 simultaneously with expansion and contraction of the tension material 11 in the cured grout material 15. Thus, it is inserted into the grout material 15 as a part of the ground anchor 10 in a state where the adhesion to the grout material 15 is cut.

  The anchoring method of the anchor body 12 to the ground is not limited to the example shown in the figure. The anchor body 12 is inserted into a drilling hole 14 formed in the ground and then injected by grout material into the bag body. It may be fixed in the ground by expanding, and in that case, it is not always necessary to fill the grout material 15 in the hole 14.

  The end of the cable 2 on the ground surface side is inserted or bypassed with a fixing plate 16 on which a head fixing body 13 integrated with the end of the tension material 11 is fixed, and the tip of the cap 18 in the axial direction; Alternatively, one end of the cap 6 is inserted into the case 6 which is inserted (fixed) around the cap 18 and directly or indirectly through the rotating body 3 pivotally supported in the case 6. Directly or indirectly connected to the spring 4.

  “Indirectly via the rotating body 3” means that a tension transmission member 5 such as a chain connected (coupled) to the case 6 side of the cable 2 is wound around the rotating body 3 and passes through the rotating body 3. . The end of the cable 2 on the anchor body 12 side is directly or indirectly connected to any part of the anchor body 12 or to any part of the section of the tendon 11 near the anchor body 12. Along with the anchor body 12, the anchor body 12 is placed in a fixed state in the stationary layer in the ground. In the drawing, the end of the cable 2 on the anchor body 12 side is connected to the connecting member 19 connected (coupled) to the anchor body 12. The connecting member 19 may be connected to a portion of the head fixing body 13 located in the grout material 15 as shown in FIG. 2 in order to adjust the orientation of the cable 2 in the grout material 15.

  As shown in FIG. 3, the case 6 is joined to the tip (upper end) of the cap 18, and is integrated with the bottom plate 61 for connecting (connecting) one end of the spring 4 to the opposite side of the cap 18 of the bottom plate 61. The support member 7 for pivotally supporting the rotating body 3 is accommodated, and the end of the cable 2 is connected to the spring 4 directly or indirectly by the end of the cable 2 via the spring 4 and the case 6. Is fixed to the head fixing body 13. In the drawing, the bottom plate 61 and the support member 7 are manufactured separately, but may be integrated. As shown in FIG. 3, the bottom plate 61 is formed with an insertion hole 61a through which the cable 2 is inserted.

  In the drawing, a coil spring is used as the spring 4. In this case, the hook at one end of the spring 4 is connected directly to the bottom plate 61 or a ring 62 connected to the bottom plate 61, and the hook at the other end is connected to the cable 2, Alternatively, the cable 2 is connected to a tension transmission member 5 such as a chain or belt that is a part of the cable 2.

  When the cable 2 or the tension transmission member 5 that is connected to the cable 2 and is part of the cable 2 is accommodated in the case 6 in a state of being stretched via the rotating body 3, FIG. ), The support shafts 3a serving as the rotation shaft of the rotating body 3 are arranged in a plane orthogonal to the axis of the tension member 11 because the sections on both sides via the rotating body 3 are arranged in parallel with each other. It is supported by the support material 7 in the state of facing the direction. The rotating body 3 is supported by the support member 7 (support plate 71) or is rotatably supported by a fixed support shaft 3a. Alternatively, as shown in the figure, the support shaft 3a in which the rotating body 3 is integrated is supported (supported) rotatably on the support material 7 (support plate 71).

  In the drawing, as shown in FIG. 4, the sprocket as the rotating body 3 is integrated with the support shaft 3 a, so that the support shaft 3 a is attached to the support plates 71, 71 opposed to the box-like support material 7. And is supported rotatably around the axis. The bearing member 3 b is accommodated in a housing 72 fixed to the surface side of the support plate 71, and the support shaft 3 a is rotatably supported with respect to the support plates 71 and 71 in the housing 72.

  A sprocket serving as the rotating body 3 is wound around a chain serving as a tension transmission member 5 which is a part of the cable 2 while meshing. The chain is coupled to the cable 2 at one end and to the spring 4 at the other end. The chain 4, that is, the tension of the cable 2 acts on the spring 4, and the restoring force of the spring 4 keeps balance with the tension of the cable 2, so that the spring 4 is moved according to the movement of the cable 2 relative to the fixing plate 16 from the normal state. Expands and contracts.

  As described above, the cap 18 that covers the head fixing body 13 is integrated with the case 6 that houses the tension force fluctuation display device 1 including the cable 2. It is installed at the same time when it is installed (fixed) on the plate 16. Here, since the section of the cable 2 disposed in the ground is embedded in the grout material 15 together with the tension material 11, the distal end portion of the section protruding from the fixing plate 16 of the cable 2 (the end portion on the spring 4 side). ) Or the tension transmission member 5 is not connected to the spring 4 until the installation of the cap 18 (case 6) is completed, and the cable 2 (the tension transmission member 5) is connected to the spring 4 after the installation of the cap 18 is completed. Is done. Alternatively, the spring 4 to which the cable 2 (tension transmission member 5) is connected is placed in a state where it is not connected to the bottom plate 61, and the spring 4 is connected to the bottom plate 61 after the installation of the cap 18 is completed.

  From the normal state shown in FIG. 1- (a) where the tension material 11 is given tension and embedded in the ground and is not further expanded or contracted, for example, as shown in FIG. Is moved to the non-moving layer side, the tension material 11 is relaxed, so that the length of the section existing in the ground of the cable 2 decreases and the length of the section of the cable 2 protruding from the ground increases. To do. As a result, the spring 4 that keeps the balance with the cable 2 contracts from the normal state due to the restoring force, so that the rotating body 3 rotates to the spring 4 side. FIG. 1B shows a state in which the display needle 8 that is integrated with the rotating body 3 and displays an enlarged amount of rotation of the rotating body 3 is rotated toward the contraction (−) side of the spring 4. When the tendon 11 relaxes, the tension of the tendon 11 decreases.

  On the other hand, when the ground surface moves from the normal state shown in (a) to the opposite side of the non-movable layer as shown in (c), the tension material 11 is more tensioned than normal, so that the ground of the cable 2 is The length of the section existing inside increases, and the length of the section protruding from the ground of the cable 2 decreases. As a result, the spring 4 is attracted to the rotating body 3 side from the normal state and is extended, so that the rotating body 3 rotates to the cable 2 side. FIG. 1C shows a state in which the display needle 8 integrated with the rotating body 3 is rotated toward the extension (+) side of the spring 4. When the tendon 11 is tensed, the tension of the tendon 11 increases.

  As the cable 2 expands and contracts, the rotator 3 rotates to either the spring 4 side or the cable 2 side. From the rotating state of the rotator 3 alone, the observer on the ground surface moves to either side. It may be difficult to read (recognize) immediately if it is rotating. Therefore, for the purpose of enhancing the effect of transmitting the fluctuation (expansion / contraction) of the tension of the tendon due to the rotation of the rotating body 3 to the observer, as shown in FIG. 8 is integrated. The display needle 8 is integrated with the rotator 3 to rotate in conjunction with the rotation of the rotator 3, but the tip is rotated around the rotation center θ of the rotator 3 by a rotation angle θ × length R. Since the image is enlarged and displayed, it has a function of enhancing the effect of transmitting the rotation angle θ to the observer.

  As shown in FIGS. 4 and 5, which are cross-sectional views of FIG. 3, the indicator needle 8 is integrated by being joined to the support shaft 3 a of the rotating body 3. The tip is oriented to point to the neutral position (0 position) as shown in FIG. Although it is arbitrary which position the tip of the display needle 8 points to is the neutral position, the neutral position is when the display needle 8 faces the axial direction of the tendon as shown in FIG. By setting so as to be, it is determined whether the tension material 11 is immediately stretched (increase in tension) or contracted (decrease in tension) from the direction of the indicator needle 8. It becomes easy.

  In order to easily transmit the position indicated by the tip of the display needle 8 to the observer, as shown in FIG. 5, the rotation angle θ from the normal time of the display needle 8 on the back side (support material 7 side) of the display needle 8. Corresponding to the above, a display board 9 calibrating the degree of fluctuation of the tension of the tension material is arranged and joined to the support material 7. For example, as shown in FIG. 4, the display plate 9 is held by a housing 72 joined to the support plate 71 and joined to the support plate 71 in a state where it overlaps the surface of the support plate 71.

  The tension change amount ΔT0 of the tendon material 11 is expressed as ΔT0 = E0 · A0 · (ΔL0 / L0) using the cross-sectional area A0 and the elastic modulus E0 of the tendon material 11, and thus the expansion / contraction amount ΔL0 of the tendon material 11 is ΔL0. = (ΔT0 · L0) / (E0 · A0).

Here, for example, the cross-sectional area A0 = 270.9mm ² tendon 11, the elastic modulus E0 = 190kN / mm ^2, the natural length L0 = 15.96m, fixing load (design load) when the T0 = 270.2kN, tension When the tension change amount ΔT0 of the material 11 is reduced by 20% from the fixing load, the tension material 11 has ΔL0 = (− 0.2 × 270.2 × 15.96 × 1000) / (270.9 × 190) = −. Shrink by 16.76 mm. When the change amount ΔT0 of the tension of the tendon 11 is reduced by 10% from the fixing load, the tendon 11 contracts by ΔL0 = −8.38 mm. On the other hand, when the tension ΔT0 of the tendon 11 increases by 10% from the fixing load, similarly, ΔL0 = 8.38 mm, and when it increases by 20%, ΔL0 = 16.76 mm.

  The amount of expansion / contraction ΔL0 from the normal state of the tension member 11 and the rotation angle Δθ (degree) of the rotating body 3 are in a relationship of ΔL0 = π · r · Δθ / 180 (degrees) where r is the radius of the rotating body 3 ( When the unit of Δθ is radians, ΔL0 = r · Δθ), and from the expansion / contraction amount ΔL0 of the tension member 11, the rotation angle Δθ of the rotating body 3 is obtained as Δθ = (180 · ΔL0) / π · r.

  Assuming that the radius r of the rotator 3 is 15.27 mm, when the tension ΔT0 of the tendon 11 is reduced by 10% from the fixing load, Δθ = −31.4 degrees, and when rotating to the contraction side, and when it is reduced by 20%, Δθ = -62.9 degrees, rotate to contraction side. On the other hand, when the tension ΔT0 of the tendon 11 increases by 10% from the fixing load, Δθ = 31.4 degrees rotates to the expansion side, and when it increases by 20%, Δθ = 62.9 degrees rotates to the expansion side.

  The center angle from the neutral position corresponding to the degree of change in tension ΔT0 of the tendon 11 is displayed on the display board 9 formed in a fan shape as shown in FIG. Immediately from the position of the overlapping display needle 8, it is possible to grasp whether the variation of the tension ΔT0 is on the expansion side or the contraction side, and how much the variation of the tension ΔT0 is. For example, as shown in the figure, 0 is entered with the direction of the indicator needle 8 when the tension change amount ΔT0 is 0 as the neutral position, and 10% and 20% increase and 10% and 20% decrease on both sides in the circumferential direction. If a straight line passing through the center of the fan shape that displays the angle of the time is entered, it is recognized at a glance which range the indicator hand 8 is in, so that the effect of accelerating the understanding of the observer is utilized. In this case, when the rotating body 3 is viewed in the center direction, the fan-shaped center and the center of the rotating body 3 are matched.

  When the indicator needle 8 (rotating body 3) rotates from the neutral position shown in FIG. 1- (a) to the spring 4 side as shown in FIG. 1 (b), the tension force of the tension material 11 decreases, and the tension material 11 Since the effect of restraint (stabilization) of the ground is reduced, the cap 18 covering the head fixing body 13 is removed from the fixing plate 16 according to the degree of the rotation angle θ, and the fixing material 17 is once released, the head fixing body 13 is re-tensioned, and the tension of the tension member 11 is increased. The degree of the rotation angle θ means that the rotation angle θ exceeds a certain amount, for example, the rotation angle exceeds a boundary line of −20%.

  Since the case 6 to which the spring 4 is connected is integrated with the cap 18, when the cap 18 is removed, the cable 2 (tension transmission member 5) connected to the spring 4 is disconnected from the spring 4, The spring 4 is removed from the case 6 (bottom plate 61), and after adjusting the tension, the cable 2 or the spring 4 is connected to the spring 4 or the case 6.

  On the other hand, when the display needle 8 (rotating body 3) is rotated from the neutral position to the cable 2 side as shown in (c), it indicates that the tension force of the tension material 11 is increased from the normal time. For example, when the rotation angle θ exceeds a certain amount, such as when the rotation angle exceeds a 20% boundary line, the tension of the tension member 11 is relaxed and reduced. Also in this case, the cap 18 is removed from the fixing plate 16, and the fixing material 17 is once released.

  Whether the tension of the tension material 11 is increased or decreased, the tension material 11 is fixed to the fixing plate 16 by the fixing material 17 after the tension force of the tension material 11 is adjusted, and the cap 18 with the case 6 is attached. The periphery of the head fixing body 13 is fixed to the fixing plate 16 and returned to the current state.

  In order to easily recognize the position of the display needle 8 with respect to the display board 9 even at night, by directing light onto the surface of at least one of the display board 9 and the display needle 8 even in the dark. It is effective to stick a sheet (retroreflective material) having a retroreflective function that allows reflected light to reach the observer's viewpoint.

  In addition, the display needle 8 is integrated with the rotating body 3 and interlocks with the rotation of the rotating body 3, but the display needle 8 has a direction in which the absolute value of the rotation angle of the rotating body 3 increases from zero. It is locked only in the positive direction and the negative direction, and is in a stationary state by the frictional force between the display plate 9 and the like at the angle reached even when the display needle 8 is returned to the 0 side by the spring 4. It is possible to confirm the maximum rotation angle recorded before the observer recognizes the display needle 8 by overlapping the placing needle to be maintained. When the stylus displays a maximum angle larger than the rotation angle displayed by the current display needle 8, it indicates that the tension material 11 has previously paid a tension corresponding to the maximum angle. Since it shows, it also turns out that the tension material 11 may yield depending on the magnitude of the tension force, and determines whether or not the tension material 11 (ground anchor 10) itself needs to be replaced. Is also possible.

1 …… Tension force fluctuation display device,
2 ... Cable, 3 ... Rotating body, 3a ... Support shaft, 3b ... Bearing material,
4 ... Spring, 5 ... Tension transmission member,
6 ... Case, 61 ... Bottom plate, 61a ... Insertion hole, 62 ... Ring, 7 ... Support material, 71 ... Support plate, 72 ... Housing,
8 …… Indicator, 9 …… Indicator,
10 …… Ground anchor,
11 ... tension material, 12 ... anchor body, 13 ... head fixing body,
14 ... drilling hole, 15 ... grout material, 16 ... fixing plate, 16a ... insertion hole,
17 ... Fixing material, 18 ... Cap, 19 ... Connecting material, 20 ... Protective block.

Claims (2)

A tension material embedded in the ground in a state where tension is applied, an anchor body connected to the tip side of the ground side of the tension material and fixed in the ground, and a head on the ground surface side of the tension material In the ground anchor provided with a head fixing body connected to the section and fixed to the ground surface in a state exposed to the ground surface,
It is constructed between the anchor body and the head fixing body, and is directly or indirectly connected to the anchor body at the end on the anchor body side, and the head fixing body at the end on the head fixing body side. Directly or indirectly connected to a spring directly or indirectly connected to a spring, and directly or indirectly supported by the head fixing body in a freely rotatable manner, in conjunction with expansion and contraction of the tension material A rotating body that rotates ,
A tension transmission member is connected to the end of the cable on the spring side, the spring is connected to the other end of the tension transmission member, and the rotating body is in contact with or meshing with the tension transmission member. A tension anchor fluctuation display device for a ground anchor. The tension anchor fluctuation display device according to claim 1, wherein a display needle having a length larger than the radius of the rotating body is integrated with the rotating body .

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