JP2001201334A - Displacement measuring device - Google Patents

Abstract

(57) [Problem] To provide a displacement measuring device that can measure with one displacement sensor even when measuring three independent displacements in the coaxial direction. SOLUTION: The displacement measuring device has three displacement transmitting rods 2.
The face material 25 urged by the spring 24 is crimped to the end of 3. The three displacement transmission rods 23 are arranged on the same circumference in parallel with the borehole axis direction, and the displacement measuring pins 26 located on the circumference parallel to this are pressed against the opposite surface of the face material 25. I do. The displacement measuring pin 26 is provided at an end of a rotating body 27 that is axially movable and is disposed at the center of the shaft. The rotating body 27 is also pressed in the direction of the face material 25 by the spring 28. The rotating body 27 that responds in the axial direction with the rotation of the displacement measuring pin 26 transmits the axial displacement to one displacement sensor 29 that does not rotate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to the measurement of rock behavior for stable design and construction of rock internal structures in the field of civil engineering or geophysics, the monitoring of behavior for detecting the destruction of rock material, and the monitoring of earthquake disaster prevention. Measuring device for measuring relative displacement of discontinuous surface in rock mass related to fault behavior monitor.

[0002]

2. Description of the Related Art In order to accurately measure the behavior of a discontinuous surface such as a crack or a joint existing in a rock, the measurement is performed in the rock avoiding the vicinity of the rock surface which is affected by a loose area due to a cavity or a tunnel. At the same time, three-dimensional measurement for evaluating the displacement vector and its opening in the discontinuous plane is considered to be indispensable, but it has not been possible to measure with conventional practical techniques.

As shown in FIG. 8, a three-dimensional displacement gauge of a discontinuous surface which only realizes measurement at a well in a rock is a front structure 1 which is fixed to a rock 102 sandwiching a discontinuous surface 104, respectively.
06 and the rear structure 107, and the front structure 1
Reference numeral 06 denotes three measurement surfaces 108 orthogonal to each other at the rear end, and the rear structure 107 includes three displacement sensors 110 at the front end facing the respective measurement surfaces 108, and the three-dimensional displacement meter 101 In this configuration, the relative displacement between the front structure 106 and the rear structure 107 is detected by a combination of three sets of measurement surfaces 108 and displacement sensors 110.

[0004]

However, the conventional three-dimensional displacement meter 101 has a disadvantage in that a separate displacement sensor 110 must be installed corresponding to each measurement surface 108, and the sensor arrangement is complicated. . The displacement sensor 110 is provided on each measurement surface 1
Since the sensor axis is arranged in a direction perpendicular to 08, the displacement measurement range with respect to the diameter of the well 103 is restricted by the displacement sensor 110 to be used, and the applicable hole diameter is limited. In particular, it cannot be applied to a lock bolt hole having a diameter of about 43 mm, which is frequently used in tunnel excavation and a cavity construction site.

Also, a displacement sensor 110 installed in a rock mass
Has a problem in reliability because measurement data is affected by thermal expansion of the sensor itself and its mounting structure material due to temperature changes.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and provides a displacement measuring device which can measure even three independent displacements in a coaxial direction with a single displacement sensor and which has a simple sensor arrangement. It is intended to be. In addition, diameter 5 in the bedrock
It is an object of the present invention to provide a displacement measuring device capable of measuring a displacement in a radial direction of a well, even in a small borehole of 0 mm or less, and having a wide measurement range. It is another object of the present invention to provide a displacement measuring device having a temperature compensation function capable of correcting measured displacement data even when a temperature change occurs in the rock.

[0007]

According to a first aspect of the present invention, there is provided a displacement measuring device comprising: three displacement transmitting rods arranged on the same circumference and arranged in a coaxial direction;
A surface material that is stably held in contact with the displacement transmission rod, a displacement measuring pin that rotates on a circumference parallel to the circumference, and a tip of the displacement measurement pin always contacts the surface material. An elastic member for pressing, and a displacement sensor for measuring an axial displacement of the displacement measuring pin are provided.

[0008] The displacement transmission rod is for displaying the displacement in three different places directly or after changing the direction, and then displaying the displacement in the same axial direction.
The mounting positions of the two are adjusted so that the displacement measuring pin can be positioned on the extension of the rod. The face material is urged toward the rod side so as to be stably held by the three rods. The displacement measuring pin is axially movable and protrudes from an end of a rotating body disposed at the center of the shaft. This rotating body is also urged in the direction of the face material by an elastic member. For this reason, the displacement measuring pin rotates while always in contact with the surface of the face material, and measures the displacement of three points on the circumference corresponding to the displacement of each rod. The rotating body that responds in the axial direction with the rotation of the displacement measuring pin does not rotate its axial displacement.
It is transmitted to the displacement sensor of the table.

According to a second aspect of the present invention, there is provided a displacement sensor, wherein a sensor shaft is arranged in a well axis direction, and a lower end portion is pivotally supported, and an upper end portion is in contact with the measurement surface. It has a substantially U-shaped cantilever measuring arm connecting the lower end of the side to the sensor axis, and measures radial displacement in two or more directions perpendicular to the well axis.

[0010] This displacement measuring device is used for measuring a diameter of 50 m in a bedrock.
m in order to measure three-dimensionally the relative change between the two rocks that sandwich a discontinuous surface such as a crack by installing them in a small well that is smaller than or equal to at least three orthogonal surfaces of the front structure fixed to one rock well. The displacement is measured in at least three directions orthogonal to the measurement surface in a measurement surface and a rear structure fixed to the other rock well.

Two or more substantially U-shaped cantilever measuring arms are arranged so as to cross each other while being shifted from each other. The displacement in the radial direction appears as the amount of movement of the upper side of the cantilever, but can also be measured by a displacement sensor arranged in the axial direction by simultaneously moving the side in the well axis direction.

Since the amount of movement is proportional to the distance from the fulcrum at the tip of the lower side, the amount of displacement can be reduced. Therefore, it becomes possible to measure a cantilever displacement larger than the measurement range of the displacement sensor in the small borehole.
This displacement amount conversion operation is also applicable to a displacement sensor that measures an axial displacement.

In this displacement measuring device, if the axial displacement and the radial displacement are converted into the movement of three displacement transmitting rods, the displacement sensor according to claim 1 can be used.

According to a third aspect of the present invention, a temperature sensor is disposed on the front structure, and a differential transformer type displacement sensor which is not affected by a normal temperature change is used as the displacement sensor. Is what you do. In order to correct the influence of the temperature change in the rock on the measurement data due to the thermal expansion of the material, the measured displacement data is immediately corrected by multiplying the detected temperature change by a correction coefficient.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows an example in which a displacement measuring device is installed to measure three-dimensional deformation of a discontinuous surface in a rock.
Small borehole 3 of 0 mm or less (for example, φ43 mm or φ46 m
m) is drilled and fixed to both rocks sandwiching a discontinuous surface 4 such as a crack.

As shown in FIG. 2, the displacement measuring device 1 has a front structure 6 fixed and installed by a fixing means 5 in one rock 2a sandwiching a discontinuous surface 4, and a similar structure in the other rock 2b. And a rear structure 7 fixed and installed by a simple fixing means 5. The rear structure 7 is a member separate from the front structure 6, but is installed in a state of being in contact with each other.

The front structure 6 is a cylindrical member whose tip is reduced in diameter, and has three measurement surfaces 8 at its rear end which are flat and intersect at right angles to each other. On the other hand, the rear structure 7 is also a cylindrical member, and at the tip thereof, one bar-shaped measuring element 9a and two substantially U-shaped measuring elements 9b in three axial directions perpendicular to each measuring surface 8 are provided.
9c are provided, each of which is connected to three displacement sensors 10 respectively.

The fixing means 5 comprises a fixing pin 5a which crosses the radial direction of each of the structural bodies 6, 7 and a fixing guide 5b provided on the outer surface of the cylindrical member, and the hydraulic pressure is applied to the fixing pin 5a via a pressure line 5c. Is supplied and inserted into the well 3 as the displacement measuring device 1 in which the structures 6 and 7 are integrated. A waterproof seal 1 as a water-resistant member that is freely deformed so that groundwater in the well 3 does not enter the gaps between the structures 6 and 7.
1 protects the measurement surface 8 and the displacement sensor 10.

Next, details of the displacement measuring section will be described with reference to FIGS. FIG. 3 is an enlarged sectional view of a central portion of the displacement measuring device, and FIGS. 4, 5, and 6 are sectional views taken along line IV-IV of FIG.
It is each sectional drawing which shows V section and VI-VI section. The measurement surface 8 of the front structure 6 is composed of a well axis orthogonal surface 8a and two well axis parallel surfaces 8b and 8c extending perpendicularly to the rear and intersecting at right angles to each other.

On the other hand, the displacement sensor 10 arranged on the support base 12 of the rear structure 7 in the borehole axis direction is a differential transformer type displacement sensor (LVDT).
And a displacement transmission rod 10c urged in the direction of the front structure 6 by a spring 10b. Due to the movement of the displacement transmission rod 10c, a core 10d formed at the tip thereof moves in the differential transformer section 10a, detects a proportionally changing secondary signal, and outputs it as a DC signal, thereby obtaining a DC signal. Detect displacement.

The differential transformer 10a is connected to the connection line 13
And an amplifier 15 via a relay control switch 14 and a signal line 16 to an external control device (not shown).

The substantially U-shaped tracing stylus 9b, 9c abutting on the bore well axis parallel surface 8b, 8c of the measuring surface 8 has an upper side 17 abutting its tip against the measuring surface 8 and a tip end of the displacement transmitting rod 10c. Side 18 connecting lower end to annular portion 10e to be formed
And a lower side 19 whose lower end is rotatably supported by a pin 20 and converts displacement in the borehole radial direction into movement in the borehole axial direction. Since the two substantially U-shaped tracing styluses 9b and 9c can be arranged in an intersecting state, the size of the device can be reduced.

Further, the bar-shaped measuring element 9a abutting on the surface 8a orthogonal to the borehole axis has an annular portion 9d formed at its rear end hinged to the plate 21. The plate member 21 is a member whose lower end is rotatably supported by the pin 20, and connects the annular portion 10 e of the displacement transmission rod 10 c above the pin 20.

Since the displacement of the displacement transmission rod 10c is proportional to the distance from each fulcrum, the displacement can be reduced by mounting the displacement transmission rod 10c closer to the measurement point. For example, the displacement of the borehole axis direction ± 10 mm to ± 2 mm,
A displacement of ± 6 mm in the borehole radial direction can be converted to ± 2 mm. That is, a cantilever displacement larger than the measurement range of the displacement sensor 10 can be measured in the small borehole 3.

A temperature sensor 22 is provided in front of the support base 12 of the rear structure 7 that houses the displacement sensor 10. The temperature sensor 22 is for avoiding the influence of the temperature change in the rock 2 on the measurement data on the measurement data in the long-term measurement monitor, and simply corrects the deformation accompanying the temperature change by using the linear expansion coefficient of the material. The LVDT used for the displacement sensor 10
Adopts the one that has little effect on the normal temperature change.

Next, another embodiment using one displacement sensor will be described with reference to FIG. The displacement measuring device shown in FIG.
The face material 25 urged by the spring 24 is pressed against the ends of the three displacement transmission rods 23. 3 displacement transmission rods 2
3 are arranged on the same circumference in parallel with the borehole axis direction, and the displacement measuring pins 26 located on the
To the opposite surface of the face material 25.

The displacement measuring pin 26 is provided at an end of a rotating body 27 which is movable in the axial direction and is disposed at the center of the shaft. The rotating body 27 is also pressed in the direction of the face material 25 by the spring 28. The rotator 27 includes a disk 27a on which a displacement measuring pin 26 protrudes from the front surface, a cylindrical sliding gear 27b provided on the back surface thereof, and a spindle 27c protruding from the back surface and having a spring 28 mounted thereon. The tip of the spindle 27c is inserted into a non-rotating displacement sensor 29 and used as a core 27d of the LVDT.

The sliding gear 27b slidably meshes with a driving gear 31 rotated by a motor 30, and is connected to an external control device (not shown) via a signal line 32. The displacement transmitting rod 23 directly or changes the direction of the displacement at three different positions and then displays the displacement in the same axial direction. The displacement measuring pin 26 rotates while passing along the extension of each rod while measuring the displacement. Is transmitted to the outside through the signal line 33.

[0029]

As described above, in the displacement measuring device according to the first aspect, the surface material stably held by contacting the three displacement transmission rods and the axial displacement by contacting the surface material are provided. Is provided with a displacement measuring pin for measuring
Even when measuring individual displacements, the measurement can be performed by one displacement sensor, and the sensor arrangement is simplified.

In the displacement measuring device according to the present invention, since the displacement sensor is arranged in the borehole axis direction and has a substantially U-shaped cantilever measuring arm, the radial displacement orthogonal to the borehole axis is arranged in the axial direction. It is measured by the displacement sensor.
Since the measuring arms are substantially U-shaped, they can be arranged in an intersecting state, and the size of the device can be reduced. This results in a diameter of 5
It can be applied to small boreholes of 0 mm or less. In addition, since the cantilever can reduce the amount of displacement, it is possible to measure a cantilever displacement larger than the measurement range of the displacement sensor in the small borehole, and the measurement range can be expanded.

In the displacement measuring device according to the third and fifth aspects, since the temperature sensor is provided and the differential transformer type displacement sensor is used, the measured displacement data can be corrected even if a temperature change occurs in the rock. .

The displacement measuring device according to the fourth aspect of the present invention is provided with a substantially U-shaped cantilever measuring arm, a face member that contacts three displacement transmitting rods, and a displacement measuring pin that contacts the face member. The measurement range of the three-dimensional relative change of the bedrock sandwiching the surface can be expanded, and the device can be reduced in size, simplified, and reduced in cost.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing an installation state of a displacement measuring device.

FIG. 2 is a sectional view of a displacement measuring device.

FIG. 3 is an enlarged sectional view of a central portion of the displacement measuring device.

FIG. 4 is a sectional view showing a section taken along line IV-IV of FIG. 3;

FIG. 5 is a sectional view showing a VV section in FIG. 3;

FIG. 6 is a sectional view showing a section taken along line VI-VI of FIG. 3;

FIG. 7 is an enlarged sectional view of a center portion of a displacement measuring device according to another embodiment.

FIG. 8 is a sectional view of a conventional displacement measuring device.

[Explanation of symbols]

 23 Displacement transmission rod 24 Spring 25 Face material 26 Displacement measuring pin 27 Rotating body 28 Spring 29 Displacement sensor

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G01D 21/00 G01D 21/00 D G01V 9/00 G01V 9/00 D (71) Applicant 500030482 Science Research Institute 1794 Kamiwada, Yamato City, Kanagawa Prefecture (74) The above three agents 100098453 Patent Attorney Yutaka Iigo (72) Inventor Masayuki Kosugi 16-3 Onogawa Tsukuba City, Ibaraki Pref. 72) Inventor Yuki Onodera 3-103 Onuma, Kasukabe City, Saitama Prefecture Inside Terra Co., Ltd. (72) Inventor Yu Yu 1794 Kamiwada, Yamato City, Kanagawa Prefecture F-term in Geological Science Research Institute Co., Ltd. CC30 EE01 EE41 EE62 EE64 FF07 GG66 HH07 HH22 HH32 2F063 AA04 AA35 BA17 BD15 CA10 CA34 CB01 DA02 DA04 DB06 DC08 DD02 DD04 GA13 2F069 A A04 AA06 AA68 BB40 DD20 DD25 DD27 EE02 GG02 GG06 GG58 GG64 HH02 HH04 HH30 JJ10 JJ22 2F076 BB07 BD01 BD17 BE01 BE02

Claims (5)

[Claims] 1. Three displacement transmission rods which are arranged on the same circumference and are coaxially arranged, a face material which is stably held in contact with the three displacement transmission rods, A displacement measuring pin that rotates on a parallel circumference, an elastic member that presses the tip of the displacement measuring pin so as to always contact the surface material, and a displacement sensor that measures an axial displacement of the displacement measuring pin. Characteristic displacement measuring device. 2. A front part fixed to one of the rock wells to be installed in a small well having a diameter of 50 mm or less in the rock to measure three-dimensionally a relative change between the two rocks sandwiching a discontinuous surface such as a crack. In a displacement measurement device including at least three measurement surfaces orthogonal to each other of a structure and a displacement sensor that measures displacement in at least three directions orthogonal to the measurement surface in a rear structure fixed to the other rock well. , The displacement sensor,
A substantially U-shaped cantilever measurement in which a sensor axis is arranged in a borehole axis direction, and a lower end is pivotally supported, an upper end is in contact with the measurement surface, and a lower end is connected to the sensor axis. A displacement measuring device comprising an arm and measuring radial displacement in two or more directions perpendicular to a well axis. 3. A three-dimensional measurement of a relative change between two rocks sandwiching a discontinuous surface, at least three mutually orthogonal measurement surfaces of a front structure fixed to one rock well, and the other rock A displacement sensor for measuring displacement in at least three directions perpendicular to the measurement surface in a rear structure fixed to the well, wherein a temperature sensor is disposed in the front structure, A displacement measuring device using a differential transformer type displacement sensor which is not affected by a normal temperature change as a sensor. 4. The displacement measuring device according to claim 2,
A displacement measuring device using the displacement sensor according to claim 1 as the displacement sensor. 5. The displacement measuring device according to claim 2, wherein
A displacement measuring device, wherein a temperature sensor is disposed on the front structure, and a differential transformer type displacement sensor which is not affected by a normal temperature change is used as the displacement sensor.