JP3403954B2 - Rockfall detection device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting a dangerous area for predicting and warning a landslide disaster.

[0002]

2. Description of the Related Art The following system is well known as a conventional rock fall detection device. (A) Detection line type rockfall detection device: An alarm is issued when a rockfall cuts an electric wire that is energized. (B) Removable rockfall detection device: An alarm is issued when the wire connecting the fixed point and the boulder is stretched or pulled out. (C) G-sensor type rockfall detection device: A G-sensor is set at an expected rockfall location, and an alarm is issued by the vibration when the rockfall falls.

[0003]

The problems of the detecting device having such a structure are as follows: (A) and (B): (1) Since it is a wire type, the span of use is relatively narrow. (2) Once there is a rockfall, it is necessary to reline for the next detection. (3) Since the measurement ends with one detection, continuous occurrence cannot be supported. (4) Detects even when contacted by animals. (5) The size and size of rockfall cannot be measured quantitatively. (6) Rockfalls that cannot be detected over time cannot be detected.

Regarding method (C): (1) The size and size of rockfall cannot be measured quantitatively. (2) The signal size varies depending on the distance. (3) Detect the next bound signal.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rock fall detection device that solves such problems. The first structural feature of the present invention comprises a microwave transmitting means and a microwave beam receiving means from the transmitting means, and the reflected wave of the microwave beam applied to the rockfall to be detected is described above. It is provided with a monitor means arranged to be received by the receiving means, and a signal processing means for detecting the occurrence of the rockfall based on the level change of the received signal of the microwave beam in the receiving means.

The second feature is that it comprises a microwave transmitting means and a microwave beam receiving means from this transmitting means, and the receiving means receives the reflected wave of the microwave beam irradiated on the rockfall to be detected. The monitor means is arranged to receive the signal, and the signal processing means for detecting the occurrence of the rockfall based on the level change of the received signal of the microwave beam in the receiving means, the signal processing means comprising the received signal. Is divided into two or more sections, and the size and the number of rockfalls detected are detected based on the number of received signals captured in each divided section.

A third characteristic is that it comprises a microwave transmitting means and a microwave beam receiving means from the transmitting means, and the receiving means receives the reflected wave of the microwave beam irradiated on the rock fall to be detected. It comprises monitor means arranged to receive the signal, and signal processing means for detecting the occurrence of the rockfall based on the level change of the microwave beam in the receiving means, and the signal processing means measures the area of the received signal. The point is to detect the size of the rockfall and / or the amount of rockfall accumulated within a predetermined period based on the calculated area size.

A fourth characteristic is that the transmitting means has a modulating means for amplitude-modulating the microwave beam at a predetermined frequency, and the receiving means extracts an envelope of the modulated signal at the predetermined frequency from a received signal. There is a means to do.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an overall conceptual diagram showing an example of a situation where a rockfall detection device according to the present invention is installed on site. 1 is a steep mountain slope, 2 is a rockfall danger area on a steep slope, and 3 is a rockfall falling on this slope. Reference numeral 4 is a microwave transmitting means, and 5 is a receiving means of the reflected microwave beam MB from the rockfall 3. The monitor means is constituted by these.

The transmitting means 4 and the receiving means 5 are arranged in parallel at a position where the reflected wave of the microwave beam MB from the transmitting means due to the rockfall 3 can be received. The presence or absence and the size of rockfall are detected by the signal processing of the received signal level change in the receiving means 5 which receives the reflected wave of the microwave beam MB by the rockfall 3.

A transmitting means 4 constituting the present invention according to FIG.
An embodiment of the receiving means 5 and the signal processing means 6 will be described. 4a
Is a microwave transmitting antenna 5a in the transmitting means 4.
It is a receiving antenna for the microwave beam MB in the receiving means 5, and the level of the received signal changes depending on the amount of reflection of the microwave beam MB due to the falling rock 3.

In the transmitting means 4, 7 is a microwave oscillating section, which oscillates a microwave having a predetermined frequency F (for example, 10 GHz), a buffer amplifier 8 and a power amplifier 9.
The microwave is supplied to the antenna 4a via. Reference numeral 10 is a modulation circuit, which applies amplitude modulation to the output of the microwave oscillating unit 7 with a signal fm of 10 kHz, for example. Therefore, the transmission wave from the transmission antenna 4a becomes a microwave beam amplitude-modulated at 10 KHZ.

In the receiving means 5, the amplitude-modulated microwave received by the receiving antenna 5a is detected by the linear element 11 such as a diode, and the AC component is amplified by the high frequency amplifier 13 via the DC component cut capacitor 12. Reference numeral 14 is a bandpass filter having a center frequency of the modulated AC signal fm, and extracts an envelope output of a signal of the AC signal that is modulated at the frequency of the modulated AC signal fm.

Reference numeral 15 is a rectifying / smoothing circuit for the envelope output, which is a DC signal Ve proportional to the amplitude of the envelope output.
Convert to. The level change of the signal Ve is equivalent to the level change of the received microwave. Therefore, when the microwave beam MB is reflected and the increase in the received signal level is increased by Ve.
The presence and size of rockfall can be detected by monitoring the change in the level.

FIG. 3 shows an example of a change in the level of Ve due to the detection of rockfall during a predetermined period T. Reflection of rockfall causes pulse signals P1 to P7 that increase above the steady level Vs to detect seven rockfalls. . The increase level of each pulse signal is approximately proportional to the amount of reflection of the microwave beam MB, that is, the size of rockfall. In this example, P3 and P4 are large rockfalls, P2, P6 and P7 are medium rockfalls, and P1 and P5 are small rockfalls.

The DC signal Ve proportional to the amplitude of the envelope output is further processed by the signal processing circuit 16 and the filter circuit 17.
By this, level shift and noise processing are performed, and as shown in FIG. 4, it is converted into an output signal V0 of the receiving means 5 which gives normalized pulse signals P1 to P7 having a peak value according to the size of the rock fall.

Next, the signal processing means 6 for inputting the output signal V0 of the receiving means 5 will be described. 18a, 18b, 1
Reference numeral 8c is a level determination circuit for detecting rock fall sizes of three categories, large, medium and small, and is realized by a comparison function having level set values of Va, Vb and Vc (Va>Vb> Vc) for the input signal V0. To be done.

FIG. 4 shows the relationship between the normalized pulse signals P1 to P7 and the level setting values Va, Vb, and Vc. The signals P3 and P4 having peaks above the setting value Va are classified into the a category (Oishi). ), And the signals P2, P6, and P7 having a peak between the set values Va and Vb are captured in the b section (middle stone), and the signal P has a peak between the set values Vb and Vc.
1 and P5 indicate that they are captured in the c section (pebbles).

Reference numerals 19a, 19b and 19c are counter circuits for counting the capture pulses of the level judging circuits 18a, 18b and 18c, respectively. In this example, the counter 19a has 2 counters.
The number of pulses P3 and P4 is counted, the counter 19b counts five pulses P2, P3, P4, P6 and P7, and 19c counts seven pulses P1 to P7. In this embodiment, the determination of three divisions is performed. However, if the capture division is further subdivided, the level determination circuit 18
n and the counter circuit 19n may be added as necessary.

Reference numeral 20 denotes a memory circuit, which is a time base 2
With the clock CL from 1, the contents of the counters 19a, 19b, 19c in a predetermined period are read and stored. Reference numeral 21 is a signal processing circuit, which is also a time base 2
Controlled by a clock CL from 1, the classification, the number, and the time of occurrence of rockfalls are calculated based on the count value of the memory circuit, and an alarm, a display, an external transmission (symbol Q), etc. are performed.

An example of classification and number of rockfalls will be described with reference to FIG. The rockfall count values captured in the section a shown in FIG. 5A are only two, P3 and P4, and it is determined that there are two large rocks. Further, the rockfall count values captured in the b section shown in FIG. 5B are five pieces P2, P3, P4, P6, and P7, but the rockfall count value 2 of the a section is subtracted to obtain three medium stones. To be judged. Further, the rockfall count values captured in the c section shown in FIG. 5C are seven P1 to P7, but a
Rockfall count value of category 2 and rockfall count value of category b 3
It is judged as two pebbles by subtracting.

The embodiment described with reference to FIGS. 4 and 5 is
We classified the size of rockfall and the number of rockfalls based on the setting value of the microwave reception level.Since the area value of the received signal is almost proportional to the size of the rockfall, the size and the accumulated amount of all rockfalls within the specified period. Can be calculated. In FIG. 2, 23 is an area calculation means, 24 is an area calculation circuit for inputting the output signal V0 of the receiving means 5 and the clock CL, and outputs the area calculation result S to the signal processing circuit 22.

FIG. 6 is a conceptual diagram of the area calculation of each pulse signal, which is the time t given by the clock in the predetermined period T.
The size of the stone can be estimated by calculating the areas S1, S2, S3 for each pulse by the total of the rod-shaped rectangular areas as shown by hatching according to the level value of the output signal V0 corresponding to 1, t2 ... Tn. Furthermore, the accumulated amount of all the rockfalls within the predetermined period can be calculated from the total area value in the predetermined period T. The area calculation means 23 can be additionally provided to the signal processing means 6 as necessary, or the signal processing means 6 can be configured by only the area calculation means 23.

In the embodiment described above, the microwave beam uses an amplitude modulation wave having a predetermined frequency for facilitating signal processing. However, in principle, an amplitude modulation means is not provided and a microwave reception signal is received. It is possible to practice the invention by directly monitoring the level changes.

Further, in the above description, the transmitting means 4 and the receiving means 5 constituting the monitor means are realized by independent unit configurations, but it is known in a radar device or the like in which a transmitting antenna and a receiving antenna are shared by a single antenna. It is also possible to adopt a configuration of the transmission and reception integrated type.

[0026]

As described above, in the device of the present invention, the following effects can be expected as compared with the conventional system. (1) Since microwave is used as a medium for rockfall detection,
Unlike the line method, once set, it can continuously detect each rock fall. (2) By providing a time base, it is possible to record the time of occurrence. (3) The size and number of rockfalls can be classified by classifying the level of the received signal. (4) The volume (accumulation amount) of rockfall can be estimated by totaling the areas of the detected signals. (5) The measuring distance can be expanded up to about 100m,
Monitoring means can be placed in a safe area. (6) It is known that landslide occurs when the amount of rockfall per hour exceeds a certain value. According to the present invention, since the increasing pitch of the amount of rock fall can be continuously and accurately monitored, it is possible to issue a landslide warning in advance, which can contribute to clarifying the safety index of the area.

[Brief description of drawings]

FIG. 1 is an overall conceptual diagram showing an example of an on-site installation situation of a rock fall detection device according to the present invention.

FIG. 2 is a block diagram illustrating an embodiment of a transmitting means 4, a receiving means 5, and a signal processing means 6 which constitute the present invention.

FIG. 3 is a characteristic diagram showing an example of a level change due to rockfall detection during a predetermined period T.

FIG. 4 is a characteristic diagram showing a relationship between normalized pulse signals P1 to P7 and level setting values Va, Vb, and Vc.

FIG. 5 is an explanatory diagram of a processing example of classification and number of rockfalls.

FIG. 6 is a conceptual diagram of area calculation of each pulse signal.

[Explanation of symbols]

1 mountain steep slope 2 Rockfall danger area 3 falling rocks 4 Transmission means 5 Receiving means 6 Signal processing means 23 Area calculation means MB microwave beam

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takayuki Shibuya 500 Soya, Hadano City, Kanagawa Yokogawa Electronic Equipment Co., Ltd. (56) References Japanese Patent Laid-Open No. 56-157862 (JP, A) Patent 2735069 (JP, JP, B2) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01D 21/00 G01S 13/52 G06M 7/00 311

Claims (4)

(57) [Claims] 1. A monitor comprising a transmitting means and a receiving means for receiving a microwave beam from the transmitting means, the monitor being arranged so that the receiving means receives the reflected wave of the microwave beam applied to the rockfall to be detected. Means and signal processing means for detecting the occurrence of the rockfall based on the level change of the reception signal of the microwave beam in the receiving means , wherein the transmitting means has a predetermined frequency with respect to the microwave beam.
The receiving means has a modulation means for amplitude-modulating the wave number, and the receiving means is a modulation signal of the predetermined frequency from the received signal.
Rockfall detection device having means for extracting the envelope of the No. 2. A monitor comprising a transmitting means and a receiving means for receiving a microwave beam from the transmitting means, the monitor being arranged so that the receiving means receives a reflected wave of the microwave beam applied to the rockfall to be detected. Means and signal processing means for detecting the occurrence of the rockfall based on the level change of the reception signal of the microwave beam in the reception means, the signal processing means dividing the level of the reception signal into two or more sections. A rockfall detection device characterized by detecting the size and the number of rockfalls detected based on the number of received signals captured in each divided section. 3. A monitor comprising a transmitting means and a receiving means for receiving a microwave beam from the transmitting means, the monitor being arranged so that the receiving means receives a reflected wave of the microwave beam applied to a rock fall to be detected. Means and signal processing means for detecting the occurrence of the rockfall based on the level change of the microwave beam in the receiving means, the signal processing means calculating the area of the received signal and determining the area size. The rockfall detection device is characterized in that the size of the rockfall and / or the amount of rockfall accumulated within a predetermined period is detected by the method. 4. The transmitting means has a modulating means for subjecting the microwave beam to amplitude modulation of a predetermined frequency,
3. The receiving means comprises means for extracting the envelope of the modulated signal of the predetermined frequency from the received signal.
The rockfall detection device described in 3 .