JPS6010245B2 - Tilt and vibration meter for rock measurement - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tilt/vibration meter for rock measurement, which is capable of measuring the inclination of a rock mass and the vibration of a rock mass caused by an earthquake in two directions using a single pendulum.

Conventionally, convenient inclinometers for rock measurement that are equipped with a single pendulum and detect one component have been developed. must be used. However, with these conventional methods, it is extremely difficult to install two inclinometers in different directions in a long and narrow rock measurement well in order to measure rock slope. become difficult or
There is a problem that the arrangement becomes impossible. Therefore, a single pendulum that could measure the two components of the inclination was planned, but with a single pendulum equipped with a moving coil, the pendulum actually oscillates in accordance with the inclination, so it can be used in two directions. When attempting to measure the components of , there is a problem in that mutual interference occurs and errors increase. The present invention solves these problems in the two-component detection type bedrock measuring inclination meter, and also provides a bedrock measuring tilt/vibration meter that can measure rock vibrations caused by earthquakes in 20,000 directions. The purpose is to

For this reason, the convenient inclination and vibration meter for rock measurement of the present invention is equipped with a single columnar pendulum whose upper end is supported in a cylindrical body casing with a gimbal. It has a pair of permanent magnets and a single movable electrode facing the same direction, and fixed electrodes in two directions facing each other with a small gap along the sides of the movable electrode to form a capacitor with the movable electrode. is attached to the inner wall of the main body casing, and includes a pair of detection lines for passing an alternating current to each gap according to the amount of change in capacitance of each gap that changes with relative movement of the pendulum with respect to the main body casing; A pair of output lines that rectify and amplify each alternating current and guide it to the output end, and a feedback line branched from each output line are connected via a differentiating circuit to cancel out the relative movement of the pendulum with respect to the main body casing. A pair of electromagnetic coils are provided facing each of the permanent magnets and fixed to the inner wall of the main body casing, and the permanent magnets are embedded in the pendulum so that the pendulum has a gap for forming a magnetic field, and the magnetic field is It is characterized in that an end opening of the forming gap is closed to the wall of the pendulum, and the electromagnetic coil is inserted into the magnetic field forming gap through the opening □ at the end.

Embodiments of the present invention will be explained below with reference to the drawings. Figures 1 to 3 show an inclination and vibration meter for rock measurement as the first embodiment, and Figure 1 shows the internal structure of the main body casing with the main body casing cut away. A perspective view showing this, FIG. 2 is a horizontal sectional view thereof,
FIG. 3 is a horizontal sectional view of the lower end of the pendulum.

As shown in these figures, a vertically elongated columnar pendulum 1 is supported within a cylindrical main body casing 3 by a gimbal 2 at the upper end of its upper end folding part la, and is provided so as to be able to swing freely. The gimbal 2 has four cross springs 2a.
, 2b, 2c, 2d and an intermediate ring 2r.

Further, the pendulum 1 has a pair of permanent magnets 4a and 4b oriented in two directions perpendicular to each other, and has a movable electrode 5 formed in the shape of a regular square prism at the reduced diameter portion at the lower end thereof. Opposed to each permanent magnet 4a, 4b, pendulum return electromagnetic coils 17a, 17b are fixed to the inner wall of the main body casing 3, and their arrangement structure is as shown in FIG. Each permanent magnet 4a, 4b has a gap 4a for forming a magnetic field.
', 4b' are embedded in the pendulum 1 so that the gaps 4a', 4b' have end openings closed at the arms of the pendulum 1.

And through these end closures, the electromagnetic coils 17a,
17b is inserted into each magnetic field forming gap 4a', 4b'.

Further, along the side surface of the movable electrode 5, fixed electrodes 6, 6', 7, and 7' are arranged in two directions x and y perpendicular to each other, facing each other with gaps P, Q, R, and S of 4 mm, respectively. , is attached to the inner wall of the main body casing 3, so that a total of four capacitors Cx, Cx', Cy, Cy' are formed by each side of the movable electrode 5 and the four fixed electrodes 6, 6'7, 7'. .

The main body casing 3 is fixedly installed on the bedrock at the bottom of a long and narrow measurement well, and the center axis of the pendulum 1 is along the vertical direction, and the movable electrode 5 and each fixed electrode 6, 6'7, 7' The gaps P, Q, R, and S are all set to the same predetermined amount, that is, they are all set to have the same capacitance. In such a state, when the main body casing 3 inclines with the inclination of the rock, the pendulum 1 tries to maintain its vertical direction, so each gap P, Q, R , S are about to change.

By the way, an electric circuit as shown in FIG. 4 is provided between the movable electrode 5 and the fixed electrodes 6, 6', that is, at both ends of the capacitors Cx, Cx', and a high-frequency oscillator 8' serving as an alternating current oscillator is connected. A detection line 10 (
In other words, this detection line 1 has capacitors Cx, Cx
') and the amount of change in capacitance of each gap P, Q (this corresponds to the amount of change in capacitance of each capacitor Cx, Cx'). An output line 14 is provided that rectifies the signal with a rectifier 11, amplifies it with an amplifier circuit 12, and leads it to an output end 13.

An electromagnetic coil 17a is connected to a feedback line 15 branched from this output line 14 via a differential circuit 16 as a damper, and the x-direction component of the relative movement of the pendulum 1 with respect to the main body casing 3 is determined by the electromagnetic coil 17a. The excitation current is fed back and is canceled out by driving the permanent magnet 4a that is integrated with the pendulum 1.

In this way, the pendulum 1 follows the tilted slope of the main body casing 3 and maintains the tilted state, and a corresponding output is taken out from the output end 13 and applied to the fixed electrodes 6, 6' on recording paper etc. is continuously recorded as a tilt component in the direction x.

Regarding the tilt component of the fixed electrodes 7 and 7' in the direction y, a detection line that connects the fixed electrodes and the movable electrode 5 (that is, this detection line has capacitors Cy and Cy')
, an output line connected thereto, and a feedback line as a branch line thereof are provided in the same way as in the case described above, so that the y-direction component of the relative movement of the pendulum 1 with respect to the main body casing 3 is determined by the excitation current of the electromagnetic coil 17b. Permanent magnet 4 integrated with pendulum 1
This is canceled out by driving b.

Then, the tilt component in the y direction is detected from the output taken out from the output end of the output line.

In the above explanation, the case of detecting the inclination of the bedrock has been described, but by properly adjusting the differential circuit 16 as a damper described above, the vibration of the bedrock due to an earthquake can also be detected in two directions perpendicular to each other. In addition, when measuring both tilt and vibration, the pendulum 1 follows the main body casing 3 so that it takes the same attitude, so it does not swing significantly, so it is possible to detect two components. The values include almost no errors due to mutual interference between the detection systems, and accurate measurements can be made.

In addition, as can be seen from the above configuration, the entire device can be made elongated, which allows it to be smoothly inserted into long and narrow rock measurement wells, creating a tilt vibrometer suitable for rock measurement. It is possible.

Furthermore, since the entire device can be made elongated in this way, it is only necessary to dig a measurement well with a small inner diameter, and the cost for drilling the measurement well can also be reduced.

5, 6, and 7 show a second embodiment of the present invention corresponding to FIGS. 1, 2, and 3, respectively, and corresponding same reference numerals indicate substantially similar parts. In this second embodiment,
A pair of permanent magnets are arranged as a lower safe permanent magnet 4a and an upper safe permanent magnet 4b, and a non-magnetic metal plate (not shown) is interposed between them. The lower electromagnetic coil 1 faces the lower and upper permanent magnets 4a and 4b.
7a and an upper electromagnetic coil 17b.

In this case as well, as shown in FIG. 6, the lower and upper permanent magnets 4a, 4b are connected to magnetic field forming gaps 4a', 4b'
is embedded in the pendulum 1 so as to have a gap 4b' in the pendulum 1, and the end of each gap 4b' is connected to the wall of the pendulum 1.

Then, the lower electromagnetic coil 1 is connected through these end gates.
7a and the upper electromagnetic coil 17b are inserted into the magnetic field forming gaps 4a' and 4b' of the lower permanent magnet 4a and the upper permanent magnet 4b, respectively.

Furthermore, the movable electrode 5 provided at the lower end of the pendulum 1 has a side surface as a cylindrical surface with a central axis in the vertical direction, and along this side surface, x,
Curved facing type fixed electrodes 6, 6', 7, 7' in two directions of y are provided.

As a result, in this second embodiment as well, a total of four capacitors Cx, Cx', Cy, Cy' are formed by the movable electrode 5 and the four fixed electrodes 6, 6'7, 7'. This second
According to the embodiment, in addition to being able to accurately measure the inclination of the rock or the two components of vibration as in the case of the first embodiment,
By arranging the permanent magnets 4a and 4b in two stages, upper and lower, it is possible to construct the entire instrument to be more elongated so that it can be easily inserted into the elongated measurement well, and the side surface of the movable electrode 5 at the lower end of the pendulum can be made into a cylindrical surface. This has the advantage that processing is greatly simplified. As detailed above,
According to the convenient inclination and vibration meter for rock measurement of the present invention, it is possible to simultaneously measure two components of inclination and earthquake with one instrument, and the structure is simple, with the gimbal at the top of the pendulum consisting of a cross spring. This has the advantage of increasing the strength compared to a simple leaf spring and preventing damage during transportation and installation.

Further, according to the convenient inclination and vibration meter for rock measurement of the present invention, a columnar pendulum is built in the cylindrical main body casing, and the permanent magnet is arranged such that the pendulum has a gap for forming a magnetic field within the pendulum. An end port of the magnetic field forming gap opens in the wall of the pendulum, and the electromagnetic coil is inserted into the magnetic field forming gap through the end port. Therefore, the entire structure can be made elongated and compact, and this tilt-cum-vibration meter can be smoothly inserted into a long and narrow rock measurement well, making it possible to create a tilt-cum-vibration meter suitable for rock measurement. It is possible.

[Brief explanation of the drawing]

Figures 1 to 3 show a tilt/vibration meter for rock measurement as the first embodiment of the present invention. Figure 1 is a perspective view of the main body casing broken away to show the internal structure, and Figure 2 is the same. 3 is a horizontal sectional view of the lower end of the pendulum, FIG. 4 is an electric circuit diagram of the detection system of one component in the inclination and vibration meter, and FIGS. A second embodiment of the present invention is shown in correspondence with FIG. 3, in which FIG. 5 is a perspective view showing the internal structure of the main casing, FIG. 6 is a horizontal sectional view thereof, and FIG. 7 is a cross-sectional view thereof. FIG. 3 is a horizontal cross-sectional view of the lower end of the pendulum. 1...Pendulum, la...Twilight part of the upper end of the pendulum, 2...Gimbal, 2a, 2b, 2c, 2d.
...Cross spring, 2r...Middle ring, 3
...Body casing, 4a, 4b...Permanent magnet, 4a', 4b'...Gap for magnetic field forming, 5...Movable electrode, 6, 6', 7, 7' ...Fixed electrode, 8 ... High frequency oscillator, 9 ... Transformer, 10 ... Detection line, 11 ... Rectifier, 12 ... Amplifier circuit , 13... Output end, 14... Output line, 15... Feedback line, 16... Differential circuit 17a,
17b... Electromagnetic coil, Cx, Cx', Cy,
Cy'... Capacitor, P, Q, R, S...
gap. Hair Figure 1 Figure 2 Figure 3 Hair Mu Figure Hair 5 Figure 5 Hair Figure 7

Claims (1)

[Claims] 1. A single columnar pendulum is supported in a cylindrical main body casing with a gimbal at the upper end reduced diameter part, and this pendulum has a pair of permanent magnets oriented in two directions perpendicular to each other and a single movable electrode. At the same time, fixed electrodes in two directions facing each other with a small gap are attached to the inner wall of the main body casing along the sides of the movable electrode to form a capacitor with the movable electrode, and the pendulum is attached to the inner wall of the main body casing. A pair of detection lines that pass an alternating current to the gap according to the amount of capacitance change of each gap that changes with relative movement, and a pair of output lines that rectify and amplify each of the above alternating currents and lead them to the output end. is connected to a feedback line branched from each output line via a differential circuit, and is fixed to the inner wall of the main body casing facing each of the above permanent magnets in order to offset the relative movement of the pendulum with respect to the main body casing. A pair of electromagnetic coils are provided, the permanent magnet is embedded in the pendulum so that the gap for forming a magnetic field has a gap in the pendulum, and a terminal opening of the gap for forming the magnetic field is opened in a wall of the pendulum. An inclination and vibration meter for rock measurement, characterized in that the electromagnetic coil is inserted into the magnetic field forming gap through the opening at the same end.