JP2001208622A - Displacement measuring instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a displacement measuring instrument having a wide measurement range and capable of measuring displacement in the radial direction of a well even if it is a small well having a diameter of 50 mm or less in a rock bed. SOLUTION: A front structure 6 of this displacement measuring device has, on its rear end, three flat measurement surfaces 8 crossing each other at right angles, while a rear structure 7 thereof is provided, on its front end, with three displacement sensors 9 extending in three axis directions and perpendicularly confronting the respective measurement surfaces 8. The displacement sensors 9 are each provided with a pressure terminal 9c abutting on its corresponding measurement surface 8 and a loading rod 9b abutting on a pressure sensor 9a, and the two are held by a spring 9d. When any measurement surface 8 is displaced, its spring 9d is elastically deformed by means of its pressure terminal 9c, and this is transmitted as a load to its pressure sensor 9a by means of its loading rod 9b. The displacement of the measurement surface 8 is formed by using a change in the load and the spring constant of the used spring 9d.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to the field of civil engineering, and to the effect verification measurement for rock reinforcement and rock improvement methods for the stable design and construction of internal rock structures, and detection of collapse due to the progression of breakage of rock slopes. Measuring device for measuring relative displacement of discontinuous surface in rock mass related to crack behavior monitoring for earthquake.

[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 mass, it is necessary to measure the inside of the rock mass and avoid the loosened region due to a cavity or a tunnel and evaluate the behavior of the discontinuous surface. The three-dimensional measurement of is considered indispensable.

Conventionally, a “three-dimensional displacement meter on a discontinuous surface” that can only measure at a rock drilling well, as shown in FIG.
The front structure 106 and the rear structure 107 are respectively fixed to the rock 102 sandwiching the discontinuous surface 104, and the front structure 106 includes three measurement surfaces 108 orthogonal to each other at the rear end, The rear structure 107 is provided with three displacement sensors 110 at the front end facing the respective measurement surfaces 108, and the three-dimensional displacement meter 101 is configured by a combination of the three sets of measurement surfaces 108 and the displacement sensors 110. In this configuration, the relative displacement between the rear structure 106 and the rear structure 107 is detected.

Further, the three-dimensional displacement meter 101 uses a differential transformer type displacement sensor as the displacement sensor 110, and detects the displacement by moving a spindle in contact with the measurement surface 108.

[0005]

However, when the differential transformer type displacement sensor is arranged in the borehole radial direction, there is a limit to the diameter of the borehole 103 that can be applied due to its axial length.
In particular, a diameter of 43 used frequently in tunnel excavation and cavity construction sites
Not applicable to lock bolt holes of about mm.
It was necessary to drill a borehole of about 6 mm. The measurement range is also limited, and the conventional three-dimensional displacement meter 101 has a measurement limit of about ± 7 mm in axial displacement and about ± 2.5 mm in borehole radial direction displacement. Further, since three differential transformer type displacement sensors are used, there is a problem in cost.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and to provide a displacement measuring device capable of measuring displacement in a borehole radial direction even in a small well having a diameter of 50 mm or less in a rock, and having a wide measurement range. The purpose is.

[0007]

Means for Solving the Problems In order to solve the above-mentioned problems, a displacement measuring apparatus according to the present invention is installed in a small borehole in a rock mass and three-dimensionally measures a relative change between the two rock masses sandwiching a discontinuous surface such as a crack. For measurement, three measurement surfaces perpendicular to each other of the front structure fixed to one rock well, and three directions orthogonal to the measurement surface in the rear structure fixed to the other rock well In a displacement measuring device including a displacement sensor that measures displacement, the displacement sensor holds a pressure sensor, a loading rod that contacts the pressure sensor, a crimp terminal that contacts the measurement surface, and one end of the crimp terminal. And an elastic member for holding the load rod described above at the other end.

The distance between the crimp terminal and the loading rod changes due to the displacement of the measurement surface. The deflection of the elastic member, which has been changed in accordance with the relative change between the two, is transmitted as a load to a pressure sensor disposed at a subsequent stage via a loading rod. The pressure detected by the pressure sensor is converted into a deflection displacement of the elastic member.

[0009]

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 is a cross-sectional view of a displacement measuring device installed for measuring three-dimensional deformation of a discontinuous surface in a rock. The displacement measuring device 1 has a diameter of 50 m in the rock 2.
A small borehole 3 (for example, φ43 mm or φ46 mm) having a diameter of m or less is drilled and fixed to both rocks sandwiching a discontinuous surface 4 such as a crack.

The displacement measuring device 1 has a front structure 6 fixedly installed by a fixing means 5 in one rock 2a sandwiching a discontinuous surface 4 and a similar fixing means 5 in the other rock 2b. It has a rear structure 7 installed. 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 front end 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 structural body 7 is also a cylindrical member, and three displacement sensors 9 are provided at the tip of the rear structural body 7 in three axial directions perpendicular to the measurement surfaces 8.

The fixing means 5 comprises a fixing pin 5a which traverses the radial direction of each of the structures 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. In addition, 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.
0 protects the measurement surface 8 and the displacement sensor 9.

Next, the displacement sensor will be described in detail with reference to FIGS. FIG. 2 is an enlarged sectional view of a central portion of the displacement measuring device, and FIG. 3 is a sectional view showing a section taken along line III-III of FIG. 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 sensors 9 disposed on the support base 11 of the rear structure 7 are pressure sensors 9a, loading rods 9b that contact the pressure sensors 9a, and crimp terminals 9c that contact each measurement surface. A spring 9d for holding the crimp terminal 9c at one end and the loading rod 9b at the other end is provided.

When the measuring surface 8 is displaced, the spring 9d is elastically deformed via the crimp terminal 9c and transmitted as a load to the pressure sensor 9a via the loading rod 9b. Pressure sensor 9
As a, for example, a diaphragm pressure sensor is used. The minute displacement generated in the diaphragm is measured by a change in electric resistance or the like, connected to the amplifier 14 via the connection line 12 and the relay control switch 13, and the pressure value detected by the signal line 15 is transmitted to an external control device (not shown). The spring 9d is converted into a deflection displacement of the spring 9d. That is, the displacement amount of the measurement surface 8 is obtained using the load change and the spring constant of the spring 9d to be used.

When such a pressure sensor 9a is used, the measurement range is expanded to about ± 10 mm in the borehole axial direction and about ± 7 mm in the borehole radial direction, and it is possible to measure the displacement amount to about twice the conventional amount. The pressure sensor 9a may be of a simple seal type of a gauge type, and the measured values of the three displacement sensors 9 may be one.
Since the relay is switched by one amplifier, the structure is simplified and the cost is reduced.

[0017]

As described above, the displacement measuring apparatus according to the present invention is provided with the crimp terminal which comes into contact with the measuring surface and the loading rod which comes into contact with the pressure sensor, and the two are held by the elastic member. The pressure detected by the sensor is converted into a flexural displacement of the elastic member, whereby the displacement of the measurement surface can be obtained. At this time, a gauge sensor can be used as the pressure sensor, so that the diameter and cost of the measuring device can be reduced. Further, by using the pressure sensor, the measurement range can be expanded as compared with the conventional displacement measuring device.

[Brief description of the drawings]

FIG. 1 is a sectional view of a displacement measuring device.

FIG. 2 is an enlarged sectional view of a central portion of the displacement measuring device.

FIG. 3 is a sectional view showing a section taken along line III-III of FIG. 2;

FIG. 4 is a cross-sectional view of a conventional displacement measuring device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Displacement measuring device 2 Rock 3 Small borehole 4 Discontinuous surface 6 Front structure 7 Rear structure 8 Measurement surface 9 Displacement sensor 9a Pressure sensor 9b Loading rod 9c Crimping terminal 9d Spring

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G01V 9/00 G01V 9/00 B (72) Inventor Masayuki Kosugi 16-3 Onogawa Tsukuba, Ibaraki Pref. (72) Inventor Yuki Onodera 3-103 Onuma, Kasukabe-shi, Saitama F-term in Terra Co., Ltd. (reference) 2D043 AA02 AA03 AB00 BA10 BB00 2F051 AA06 AB01 AB06 AC01 BA07 2F069 AA06 BB40 DD20 DD27 GG02GG06 GG11 GG20 GG39 GG51 GG56 GG58 GG64 HH02 JJ02 JJ19 JJ25 MM04 MM11 MM17 PP04 QQ05 2F076 BB09 BD02 BD10 BD11 BD17

Claims (1)

[Claims] In order to three-dimensionally measure the relative change between two rocks sandwiching a discontinuous surface such as a crack by being installed in a small well in a rock, the front structures fixed to one rock well are mutually connected. In a displacement measurement device including three orthogonal measurement surfaces and a displacement sensor that measures displacement in three directions orthogonal to the measurement surface in a rear structure fixed to the other rock well, the displacement sensor includes: A pressure sensor, a loading rod that abuts the pressure sensor, a crimp terminal that abuts the measurement surface, and an elastic member that holds the crimp terminal at one end and the load rod at the other end. Displacement measuring device.