JP2007155550A - System for detecting collapse of sloping land - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sloping-land collapse detection system for detecting a landslide, a mudslide, etc. in a sloping land, so-called phenomenon of sloping land collapse. <P>SOLUTION: Into the slope of a sloping land, a plurality of poles having predetermined curvature portions are driven, and an optical fiber is arranged along the poles. From the optical fiber, signal light in accordance with external force is outputted with respect to inputted reference light. The optical fiber bends locally since the poles move, when a collapse phenomenon occurs in the sloping land, and the output of the signal light to be outputted changes. A detection part connected to the optical fiber judges that a collapse occurs in the sloping land, when the variation width of the output from the optical fiber exceeds a preset threshold. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sensor system that detects collapse of slopes, so-called landslides and landslides.

  Conventionally, as a system for detecting the collapse of an inclined land, a system that monitors the state of the slope by installing an electric sensor such as an inclinometer on the slope has been widely used. Recently, however, a system using an optical fiber as a sensor has been proposed. Unlike an electrical sensor, the optical fiber is not energized, so there is no need to take excessive waterproofing measures when used outdoors, it is easy to handle, and the dielectric current of other electronic devices This is because there is an advantage that it is not affected by the cause of electromagnetic noise. For example, Patent Document 1 discloses a system that uses such an optical fiber as a sensor to detect the collapse of an inclined land.

  In Patent Document 1, an optical fiber cable is fixed to a mesh-shaped pressure receiving body whose roughness is changed depending on the location so that the pressure receiving condition varies when subjected to earth and sand pressure, and this is embedded in an inclined land to be monitored. . When the slope is collapsed, the pressure receiving body that has been subjected to earth and sand pressure has a part that deforms greatly and a part that does not deform so much due to the difference in the roughness of the eyes. Due to the difference in deformation, distortion occurs in the optical fiber fixed to the pressure receiving body, and the frequency of the backscattered light with respect to the input optical pulse signal is shifted. Then, by measuring the amount of frequency shift and the return time of the backscattered light, the amount of distortion of the optical fiber cable and the location where the distortion has occurred can be grasped.

JP 2001-304822 A

  In the detection system described in Patent Document 1, it is necessary to embed an optical fiber cable and a pressure receiving body in an inclined ground. Therefore, it is necessary to dig up the inclined surface over a wide range, and a very large man-hour is required. In particular, when the inclined surface is almost vertical, it is almost impossible to embed the optical fiber cable and the pressure receiving body in the brushed portion. In addition, by changing the roughness of the mesh-shaped pressure receiving body, a difference in the degree of occurrence of deformation is caused to cause distortion in the optical fiber cable. However, the optical fiber cable and the pressure receiving body are embedded. For example, if the part landslides over a wide range, the optical fiber moves in the entire area where the optical fiber is buried, so there is no significant difference in the deformation of the pressure receiving body, and the landslide cannot be detected or detected. There is a problem that sensitivity is lowered.

  In order to solve the above problems, the present invention is an inclined landslide detection system for detecting landslides such as landslides and landslides on a slope, and includes a light source that outputs a reference light, and at least a portion embedded to detect the landslide In order to detect the presence or absence of the movement of the column, the column is placed along the column to detect the presence or absence of movement of the column, and the signal light corresponding to the external force due to the movement of the column with respect to the input reference light An external force detecting means for detecting the presence or absence of an external force on the optical fiber based on the signal light, and an inclined landslide detection means for detecting an inclined landslide based on a detection result by the external force detecting means. A feature of the slope failure detection system is provided.

  Further, according to the present invention, in the above solution, a side surface of the support along which the optical fiber is partly has a curvature surface having a predetermined curvature, and when the support is moved, the optical fiber receives a tension to be brought into close contact with the curvature surface. The present invention provides a slope failure detection system characterized by bending of an optical fiber with a predetermined curvature.

  The present invention also provides an inclined land collapse detection system characterized in that, in the above solution, a plurality of support columns are provided, and each part of the optical fiber path is arranged along the plurality of support columns.

  Furthermore, the present invention is a slope landslide detection system for detecting slope landslides such as landslides and landslides on slopes, and includes a light source that outputs a reference light, and at least a portion embedded in the slope in order to detect slope landslides. The support is installed and has a groove on the upper surface, and a part of the support is arranged along the groove to detect the presence or absence of the movement of the support. An optical fiber that outputs signal light, an external force detection unit that detects the presence or absence of an external force on the optical fiber based on the signal light, and an inclined land collapse detection unit that detects an inclined land collapse based on a detection result by the external force detection unit. The present invention provides a slope failure detection system characterized by this.

  According to the present invention, in the above solution, the inner surface of the groove portion along which the optical fiber is partly has a curvature surface having a predetermined curvature, and when the support column moves, the optical fiber receives a tension to closely contact the curvature surface. In addition, the present invention provides an inclined landslide detection system characterized in that bending of a predetermined curvature occurs in an optical fiber.

  Further, the present invention provides a slope landslide detection system characterized in that, in the above solution, a plurality of support columns are provided, and each part of the optical fiber path is arranged along the grooves of the plurality of support columns. is there.

  Further, the present invention provides the above solution, comprising: an O / E converter that converts the signal light output from the optical fiber into an electrical signal; and a high-pass filter that outputs a high-frequency component of the electrical signal. The present invention provides a slope failure detection system having a reference value and comprising means for detecting the presence or absence of an external force on an optical fiber based on a comparison result between a high frequency component and a reference value.

  In the above solution, the external force detection means determines that there is an external force to the optical fiber when the high frequency component fluctuates in a range exceeding the reference value, and the slope failure detection means determines that the external force detection means has an external force. It is intended to provide an inclined land collapse detection system characterized in that it is determined that an inclined land collapse has occurred.

  Furthermore, the present invention is a slope landslide detection system for detecting slope landslides such as landslides and landslides on slopes, in order to detect slope landslides, and at least a part of the pillars installed on the slopes, An optical fiber partially disposed along the support for detecting the presence or absence of movement, and a deformation detection means connected to one end of the optical fiber to detect a deformation value and a deformation position of the optical fiber due to the movement of the support; The present invention provides a slope landslide detection system comprising slope landslide detection means for detecting slope landslide based on the detection result of the deformation detection means and specifying the position thereof.

  Further, according to the present invention, in the above solution, a side surface of the support along which the optical fiber is partly has a curvature surface having a predetermined curvature, and when the support is moved, the optical fiber receives a tension to be brought into close contact with the curvature surface. The present invention provides a slope failure detection system characterized by bending of an optical fiber with a predetermined curvature.

  The present invention also provides an inclined land collapse detection system characterized in that, in the above solution, a plurality of support columns are provided, and each part of the optical fiber path is arranged along the plurality of support columns.

  Furthermore, the present invention is a slope landslide detection system for detecting slope landslides such as landslides and landslides on slopes, and is installed on slopes with at least a part embedded in order to detect slope landslides, and grooves on the upper surface. The provided struts, an optical fiber arranged partially along the groove provided on the top surface of the struts to detect the presence or absence of the struts, and the light due to the movement of the struts connected to one end of the optical fiber. An inclined landslide detection comprising: a deformation detecting means for detecting a deformation value and a deformation position of the fiber; and an inclined landslide detecting means for detecting an inclined landslide based on a detection result by the deformation detecting means and identifying the position thereof. A system is provided.

  According to the present invention, in the above solution, the inner surface of the groove portion along which the optical fiber is partly has a curvature surface having a predetermined curvature, and when the support column moves, the optical fiber receives a tension to closely contact the curvature surface. In addition, the present invention provides an inclined landslide detection system characterized in that bending of a predetermined curvature occurs in an optical fiber.

  Further, the present invention provides a slope landslide detection system characterized in that, in the above solution, a plurality of support columns are provided, and each part of the optical fiber path is arranged along the grooves of the plurality of support columns. is there.

  According to the present invention, in the above solution means, the slope landslide detection means has a reference value, and it is determined that slope landslide has occurred based on a comparison result between the deformation value and the reference value, and the position is calculated. An inclined land collapse detection system characterized by the above is provided.

  According to the present invention, in the above solution, the deformation detecting means is an OTDR that outputs reference pulse light to the optical fiber and receives backscattered light generated from the reference pulse light and output from the optical fiber. An inclined landslide detection system is provided.

  The present invention also provides the slope failure detection system according to the above solution, wherein the wavelength of the reference light is 1480 nm or more.

  The present invention also provides the slope failure detection system according to the above solution, wherein the wavelength of the reference pulse light is 1480 nm or more.

  Further, the present invention provides the slope failure detection system according to the above solution, wherein the support column has a shape with a curvature of 10 mm or more and 60 mm or less when subjected to tension in the optical fiber along the support column. is there.

  The present invention also provides the slope failure detection system according to the above solution, wherein the optical fiber is a single mode optical fiber having a cutoff wavelength of 1260 nm or less.

  According to the first embodiment of the present invention, it is possible to reliably detect only the occurrence of a collapse such as a landslide or a landslide without erroneous detection even when an animal or a person for monitoring enters a slope. Can do. Moreover, it is not necessary to embed the sensor part in the ground, and it is only possible to fix the column to the inclined ground, so that the installation can be performed easily. In addition, since an optical fiber that does not require electrical conductivity is used for the sensor portion, when an electric sensor is used, handling is easy even outdoors where water-tightness measures are required.

  Further, according to the second embodiment of the present invention, in addition to the first embodiment, it is possible to reliably detect the place where the collapse of the inclined land has occurred.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, about the component which has the substantially same function, duplication description is abbreviate | omitted by using the same code | symbol.

  The configuration of the slope failure detection system according to the present invention will be described with reference to FIGS. Here, FIG. 1 shows an outline of the usage status of the system, and FIG. 2 shows the configuration of the slope failure detection system.

  Reference numeral 101 denotes an inclined land to be monitored, which is formed from earth or sand or concrete. 102 is a support | pillar installed in the sloping ground 101, for example, a pile corresponds to this. And the lower part is embedded in the slope so that the support | pillar 102 may not move easily with a wind and rain. Moreover, the support | pillar 102 is a pillar body which has a curvature surface which consists of predetermined curvature in a part of side surface, for example, a cylinder, an elliptical cylinder, a triangular prism, a square pillar etc. are used. However, the tip of the support column 102 may have a conical shape so as to be easily embedded in an inclined ground.

  An optical fiber, which will be described later, is provided along the support column 102. When the optical fiber is subjected to tension, bending with a predetermined curvature occurs along the curvature surface of the support column 102. In addition, when an optical fiber is along the support | pillar 102, as long as a part becomes a predetermined curvature when an optical fiber receives tension | tensile_strength, what kind of alignment method may be used. For example, as in the present embodiment, it may be along or wound around the side surface of the support column 102, or a groove portion having a predetermined curvature may be provided on the upper surface of the support column 102, and the optical fiber may be provided there. Further, the predetermined curvature on the curvature surface is in the range of 10 mm to 60 mm depending on the wavelength of the signal light transmitted through the optical fiber.

  Reference numeral 21 denotes a light source device, which outputs reference light having a wavelength of 1480 nm or more and comprising continuous light with a predetermined power. As the light source of the light source device 21, for example, an infrared LED having a short wavelength, a laser diode having a short wavelength, a dot matrix LED, or the like is used.

  Reference numeral 22 denotes an optical fiber having one end connected to the light source device 21 and outputs a signal light corresponding to an external force applied to the optical fiber 22 with respect to the input reference light. In the state where the external force is not applied to the optical fiber 22, that is, in the state where the bending below the predetermined curvature is not generated, only the transmission loss based on the material of the optical fiber is generated with respect to the input reference light. Is output. On the other hand, when an external force is applied to the optical fiber 22 to cause local bending below a predetermined curvature, a loss occurs in the reference light input by this portion. Therefore, signal light whose power is reduced or fluctuated with respect to the inputted reference light is output.

  The optical fiber 22 used in this embodiment is a single mode optical fiber having a cut-off wavelength of 1260 nm or less. Here, regarding the relationship between the bending diameter (diameter) of the optical fiber 22 and the loss, a theory for obtaining the bending loss. This will be described with reference to Expression 1 which is an expression and FIG. 3 showing the calculation result according to Expression 1.

Each count is
Pa: Bending loss [dB / m]
a: Core radius (= 5um)
R: Bending radius [m]
Δ: relative refractive index difference (= 0.2)
V: Normalized frequency (= 2)
W: Normalized propagation constant in the cladding (= 1.2)
U: Normalized propagation constant in the core (= 1.5)
Represents. Note that a value of a general single mode optical fiber is used as the relative refractive index difference Δ. The normalized frequency V, the normalized propagation constant W in the cladding, and the normalized propagation constant U in the core are values obtained when light having a wavelength of 1550 nm is passed through a single mode optical fiber.

  FIG. 3 shows the relationship between the bending diameter (diameter) and the loss calculated from the above equation when the wavelength of the input light is 1550 nm in a single mode optical fiber having a cutoff wavelength of 1260 nm. In the figure, the horizontal axis represents the bending diameter and the vertical axis represents the loss. As shown in the figure, almost no loss occurs when the bending diameter is large, but loss starts to occur when the bending diameter becomes 60 mm or less and increases in a quadratic curve. Therefore, if the optical fiber 22 is normally in a state where the bending diameter exceeds 60 mm and the bending diameter is set to 60 mm or smaller when an abnormality occurs, the presence or absence of the abnormality is detected from the optical fiber. It is possible to detect the loss of the output signal.

  FIG. 4 shows the relationship between the bending diameter and loss when the wavelength of input light is 1300 nm, 1480 nm, and 1550 nm. As shown in the figure, the loss generated per unit length increases as the wavelength of light increases.

  In this embodiment, as shown in FIGS. 1 and 2, an optical fiber 22 is run along a support column 102 installed on an inclined land 101, thereby forming a sensor unit 23. Here, as a method of running along the optical fiber 22, not only the optical fiber 22 is in contact with the support column 102 only in a limited range on the side surface, but the optical fiber 22 is wound around the entire side surface of the support column 102. And a method of providing a groove on the upper surface of the support column 102 and extending the optical fiber 22 there, although not shown. In addition, there is a certain amount of slack when moving along, and in normal times the optical fiber 22 is not in close contact with the support column 102 and is provided with a slight gap. This gap may not be so large that a clear gap is formed between the support column 102 and the optical fiber 22, and it is not necessary to apply a tension enough to stretch the optical fiber 22 in a straight line. Hereinafter, arranging the optical fiber 22 on the side surface or the upper surface of the support column 102 in such a state will be described as a general term.

  When a collapse such as a landslide occurs on the sloping land (hereinafter referred to as a sloping land collapse), the support 102 is moved, so that the optical fiber 22 receives a tension and comes into close contact with the curvature surface, and the optical fiber 22 has a predetermined portion of the support 102. Bends with the same curvature as Therefore, signal light whose power is reduced or fluctuated with respect to the reference light input to the optical fiber 22 is output, and by monitoring this signal light, it is possible to detect the occurrence of slope failure. .

  As described with reference to FIG. 4, if the wavelength of the signal light input to the optical fiber 22 is shortened, the bending diameter at which loss occurs in the optical fiber can be reduced. Therefore, signal light having a low wavelength is used. As a result, the column 102 itself can be made smaller, the curvature of the predetermined portion can be made smaller, and the sensor 23 can be made smaller. However, if the curvature of the optical fiber 22 along the curvature surface of the support column 102 is too small, the optical fiber 22 may be broken, and the optical fiber may be bent when an abnormality occurs on an inclined ground. Therefore, there is a possibility that the loss generated on the measuring instrument side cannot be detected. Therefore, in actual use, when the tension is generated in the optical fiber 22, the curvature of the curvature surface of the support column 102 is determined so that the curvature is in the range of 10 mm to 60 mm, and the curvature is about 10 mm and small. When it is about half a circle and 60 mm, it is preferable to wrap around the plurality of optical fibers 22. Correspondingly, the wavelength of light input to the optical fiber 22 is preferably 1480 nm or more.

  The loss of the optical fiber 22 occurs not only when the slope 101 collapses but also when a person, an animal, or the like who regularly monitors the slope 101 touches the optical fiber between the columns 102. However, the amount of bending that occurs is small and the loss due to this is not significant. On the other hand, the amount of bending generated in the optical fiber 22 due to the slope landslide is large, and the loss due to this is large. For this reason, it is possible to determine whether the loss is caused by slope collapse or the other such as an animal depending on the magnitude of the generated loss.

  As a method of fixing the optical fiber 22 to the support column 102, for example, a method of fixing a part with a binding band, an adhesive, or the like, or fixing a predetermined part of the optical fiber 22 to the sheet with an adhesive or the like in advance. A method of fixing a part to the column 102 with a binding band or the like can be mentioned. In the figure, the optical fiber 22 is wound around the support 102 for one turn. However, as described above, the number of windings is set according to the curvature of the support post to be wound and the wavelength of the signal light to be used.

  Reference numeral 24 denotes a detection device that detects whether or not an inclined land collapse has occurred in the inclined land 101 based on the signal light output from the optical fiber 22. Hereinafter, the internal configuration of the detection device 24 will be described. An O / E converter 25 is connected to the other end of the optical fiber 22. When signal light is input from the optical fiber 22, it is converted into an electrical signal and output. Reference numeral 26 denotes a high pass filter (hereinafter referred to as HPF), which outputs a high frequency component (1 Hz or more in this embodiment) of an output value from the O / E converter 25. Reference numeral 27 denotes a calculation unit that determines whether or not the sloped land collapse has occurred in the sloped land 101 based on the output from the HPF 26 and outputs the result. Here, how the slope failure is determined will be described with reference to FIG.

FIG. 5 shows the output value from the HPF 26, and the high frequency component is calculated for the output from the optical fiber 22. The solid line indicates the time waveform of the HPF output value, and the horizontal broken line indicates the reference voltage V _THD for determining whether or not the slope 101 is collapsed. When the optical fiber 22 is bent by a human being or an animal, a slight loss occurs. However, since it does not exceed the reference voltage V _THD , it is determined that there is no abnormality in the inclined land 101. On the other hand, when the support column 102 is caused to flow along with the earth and sand due to the landslide of the inclined land 101, the optical fiber 22 is tensioned to bend with the same curvature as the curvature surface of the support column 102, and the time waveform of the HPF output value is the reference voltage V. Fluctuates with a width exceeding _THD . For this reason, it is determined that the slope 101 has collapsed.

  Although the detection device 24 has been described above, the detection device 24 is provided with an operation unit (not shown), and is used for starting the entire system, setting a reference voltage, and the like.

  Reference numeral 28 a denotes an alarm device A, which issues an alarm based on the output from the detection device 24. Specifically, an alarm is issued when a determination result indicating that the slope 101 has collapsed is input.

Next, the operation will be described with reference to FIG. When the monitor (user of the system in the present embodiment) performs a monitoring start operation on an operation unit (not shown) of the detection device 24, the reference voltage V _THD is set (S1). Setting is performed according to the following procedure. The detection device 24 monitors the high-frequency component output value from the HPF 26 before the monitoring start operation is performed, and calculates an average value immediately before the start operation is performed and the value does not vary. Then, a preset value is added to this average value, and a reference voltage V _THD is calculated.

When the setting of the reference voltage V _THD is completed, monitoring is started, the reference light output from the light source device 21 is input to the optical fiber 22, and the signal light transmitted through the optical fiber 22 is O / E converted. It is converted into an electric signal by the device 25 (S2). Subsequently, the high frequency component of the electrical signal output from the O / E converter 25 is calculated by the HPF 26 (S3). The high frequency component value output from the HPF 26 is input to the calculation unit 27 and compared with the reference voltage V _THD (S4). Here, if the value does not exceed the reference voltage V _THD , it is determined that the optical fiber 22 is not bent with the same curvature as that of the local curvature portion of the support column 102, and monitoring is continued after returning to S2. When the fluctuation continues with a width exceeding the reference voltage V _THD , it is determined that the optical fiber 22 is bent with the same curvature as the local curvature portion of the support column 102 and the slope 101 is collapsed as the cause. (S5). When it is determined that the slope 101 has collapsed, the alarm device A28a issues an alarm notifying the occurrence of the collapse by color or sound (S6).

  As described above, according to the first embodiment of the present invention, only the occurrence of a collapse such as a landslide or a landslide has occurred without erroneous detection when an animal or a person for monitoring enters the sloped land 101. It can be detected reliably. In addition, it is not necessary to embed the sensor portion in the ground, and only the column 102 is fixed to the inclined ground 101, so that the installation can be performed easily. In addition, since an optical fiber that does not require electrical conductivity is used for the sensor portion, when an electric sensor is used, handling is easy even outdoors where water-tightness measures are required.

  Subsequently, the configuration of the second embodiment will be described with reference to FIGS. 7 and 8. FIG. 7 shows an outline of the usage status of the system of the second embodiment, and FIG. 8 shows the configuration of the system of the second embodiment.

  The inclined ground 101 and the support 102 have the same configuration as that of the first embodiment, and the support 102 is provided with a curvature surface in which a part of the optical fiber has a predetermined curvature when the optical fiber described later is placed. Further, the curvature is in the range of 10 mm to 60 mm as in the first embodiment. The optical fiber 22 is also a single mode optical fiber having a cutoff wavelength of 1260 nm or less similar to that of the first embodiment, but one end is connected to an OTDR described later and the other end is a free end. Note that the free end is preferably cut obliquely with respect to the core so that unnecessary reflected light is not generated by the light transmitted through the optical fiber 22.

  Reference numeral 31 denotes an OTDR (Optical Time Domain Reflectometer) to which one end of the optical fiber 22 is connected. The OTDR 31 outputs pulse light to the optical fiber 22 and also reflects reflected light generated by transmitting the pulse light through the optical fiber 22 ( By measuring backscattered light, it is possible to detect whether an external force is applied to the optical fiber 22 and to which position of the optical fiber 22 the external force is applied.

  The main part of the OTDR 31 includes a light source 32, an optical circulator 33, and a light receiving device 34. When pulsed reference light (hereinafter referred to as reference pulse light) is output from the light source 32, the reference pulse light is input to the optical fiber 22 via the optical circulator 33 that outputs the input light only in a specific direction. . While the reference pulse light is transmitted through the optical fiber 22, reflected light by so-called Fresnel reflection generated from the reference pulse light, that is, so-called backscattered light, is transmitted opposite to the transmission direction of the reference pulse light. The backscattered light is transmitted through the optical fiber 22 and then input to the light receiving device 34 via the optical circulator 33. Here, the relationship between the distance from the OTDR 31 and the output of the backscattered light is calculated.

  In addition, since the curvature of the curvature surface of the support | pillar 102 around which the optical fiber 22 is wound is 10 mm to 60 mm, the wavelength of the reference pulse light from the light source 32 is preferably 1480 nm or more as in the first embodiment.

  FIG. 9 shows the relationship of the output of the reflected light with respect to the distance from the OTDR 31 output from the light receiving device 34. Here, 41 indicates the relationship between the distance and output when no external force is applied to the optical fiber 22, that is, when the optical fiber is not wound around the support column 102, and the loss increases at a constant rate with respect to the distance. That is, the output is reduced. Reference numeral 42 denotes a relationship between the distance and the output when the optical fiber 22 is wound around the support column 102 and disposed on the inclined land 101 as an inclined land collapse detection sensor. In the figure, for the sake of explanation, the outputs of 41 and 42 are displayed so as to be different from each other. However, in reality, the initial values of the outputs are the same, and 41 and 42 overlap until point A. Here, each point of 43 (point A), 44 (point B), 45 (point C), 46 (point D), 47 (point E) has the optical fiber 22 run along the support column 102 or is wound. Since the optical fiber 22 is bent by being wound, the output is rapidly reduced (loss is rapidly increased). In this state, since the optical fiber 22 does not receive a large tension, the curvature of the generated bending is not as small as the curvature of the curvature surface of the support column 102. A broken line 48 indicates the relationship between the distance and the output when the slope 101 is collapsed. Here, the output at 44 and 45 is much lower than that at 42. At this point, the optical fiber 22 is subjected to a large tension, and the bending with the same curvature as the curvature surface occurs, that is, the slope is collapsed. It can be confirmed that there is.

  Reference numeral 35 denotes an arithmetic unit. From the relationship between the distance output from the light receiving device 34 of the OTDR 31 and the output, the optical fiber 22 has not been bent with the same curvature as the curvature surface, that is, the slope 101 has collapsed. Determine if there is any. In addition, it has a position information correspondence table in which information on the position where the initial loss is generated in the optical fiber 22, that is, the position where the sensor unit is installed on the inclined land to be monitored is recorded. And when collapse occurs, the position is specified from the place where the output newly decreased (loss increased). The operation device 35 is provided with an operation unit (not shown), and is used for starting up the entire system, various settings, and the like.

  Reference numeral 28b denotes an alarm device B, which notifies the information of the position where the collapse has occurred in addition to the function of the alarm device A 28a.

  Next, the operation will be described with reference to FIG. When a monitor (user of the system in the present embodiment) performs a monitoring start operation on an operation unit (not shown) of the detection device 31, the reference pulse light is input from the light source device 21 to the optical fiber 22, and the rear of this. Using the signal light output from the optical fiber 22 as the scattered light as the OTDR initial output, the point where the loss has occurred and the loss value are calculated and registered (S11). When the registration is completed, the output of the signal light with respect to the distance from the OTDR is measured in the OTDR (S12). Subsequently, the output of the signal light at the point where there is a loss in S11 and the output registered as the reference value in S11 are compared, and the increase in loss is calculated (S13).

  The increase amount calculated in S13 is compared with a preset threshold value (S14). If the threshold value is not exceeded, the process returns to S12 and measurement is continued again. . If it is determined in S14 that the threshold value has been exceeded, it is determined that an abnormality in slope landslide has occurred (S15). Next, with reference to the position information correspondence table provided in the arithmetic unit 35, it is calculated where the slope collapse occurred (S16). Then, the alarm device B28b issues an alarm notifying the occurrence of collapse by color or sound, and displays the location where the slope collapse occurred on the display unit (S17).

  As described above, according to the second embodiment of the present invention, in addition to the effects of the first embodiment, it is possible to easily calculate where the slope collapse occurred.

System usage situation diagram of Example 1 System configuration diagram of Embodiment 1 Illustration of relationship between bending diameter and loss Illustration of relationship between bending diameter and loss with wavelength as parameter HPF output explanatory diagram Operation flow of Example 1 System usage situation diagram of Example 2 System configuration diagram of embodiment 2 Explanation of OTDR output Example 2 Operation Flow

Explanation of symbols

102: support 21: light source device 22: optical fiber 23: sensor unit 24: detection device 25: O / E converter 26: HPF
27: Calculation unit 31: OTDR
35: Arithmetic unit

Claims (20)

An inclined landslide detection system that detects landslides such as landslides and landslides on slopes,
A light source that outputs a reference light;
Pillars installed on the slope in a state where at least a part thereof is buried in order to detect slope failure,
A part of the optical fiber for detecting the presence or absence of the movement of the column, and an optical fiber that outputs signal light corresponding to an external force generated by the movement of the column with respect to the input reference light;
An external force detecting means for detecting the presence or absence of an external force to the optical fiber based on the signal light;
Inclined landslide detection means for detecting landslide collapse based on the detection result by the external force detection means,
An inclined land collapse detection system comprising: The slope landslide detection system according to claim 1,
A side surface of the support along which the optical fiber is formed has a curvature surface having a predetermined curvature in part, and when the support moves, the optical fiber is in close contact with the curvature surface by receiving tension. An inclined landslide detection system characterized in that a bend with the predetermined curvature is generated. The slope failure detection system according to claim 1 or 2,
The slope landslide detection system, wherein a plurality of the columns are provided, and each part on the path of the optical fiber is arranged along the columns. An inclined landslide detection system that detects landslides such as landslides and landslides on slopes,
A light source that outputs a reference light;
A strut that is installed on the slope and is provided with a groove on the upper surface in a state where at least a portion thereof is buried in order to detect sloped land collapse,
A part of the optical fiber that is arranged along the groove to detect the presence or absence of movement of the support, and outputs an optical signal corresponding to an external force generated by the movement of the support with respect to the input reference light;
An external force detecting means for detecting the presence or absence of an external force to the optical fiber based on the signal light;
Inclined landslide detection means for detecting landslide collapse based on the detection result by the external force detection means,
An inclined land collapse detection system comprising: The slope failure detection system according to claim 4,
The inner side surface of the groove along which the optical fiber extends has a curved surface having a predetermined curvature, and when the support column moves, the optical fiber receives tension and comes into close contact with the curved surface. An inclined landslide detection system, wherein the fiber is bent with the predetermined curvature. An inclined land collapse detection system according to claim 4,
A slope landslide detection system, wherein a plurality of the columns are provided, and each part on the path of the optical fiber is arranged along a groove of the columns. The slope landslide detection system according to claim 1,
An O / E converter for converting signal light output from the optical fiber into an electrical signal;
A high-pass filter that outputs a high-frequency component of the electrical signal;
With
In addition, the external force detection means has a reference value, and includes a means for detecting the presence or absence of an external force on the optical fiber based on a comparison result between the high frequency component and the reference value. . The slope landslide detection system according to claim 7,
The external force detection means determines that there is an external force to the optical fiber when the high-frequency component fluctuates in a width exceeding the reference value,
The slope failure detection system according to claim 1, wherein the slope failure detection means determines that a slope failure has occurred when the external force detection means determines that there is an external force. An inclined landslide detection system that detects landslides such as landslides and landslides on slopes,
Pillars installed on the slope in a state where at least a part thereof is buried in order to detect slope failure,
An optical fiber partially disposed along the column to detect the presence or absence of movement of the column;
Deformation detecting means connected to one end of the optical fiber and detecting a deformation value and a deformation position of the optical fiber due to the movement of the support;
Inclined landslide detecting means for detecting an inclined landslide based on the detection result by the deformation detecting means and specifying the position thereof;
An inclined land collapse detection system comprising: The slope failure detection system according to claim 9,
A side surface of the support along which the optical fiber is formed has a curvature surface having a predetermined curvature in part, and when the support moves, the optical fiber is in close contact with the curvature surface by receiving tension. An inclined land collapse detection system characterized in that the bending of the predetermined curvature occurs. The slope failure detection system according to claim 9 to 10,
The slope landslide detection system, wherein a plurality of the columns are provided, and each part on the path of the optical fiber is arranged along the columns. An inclined landslide detection system that detects landslides such as landslides and landslides on slopes,
A strut that is installed on the slope and is provided with a groove on the upper surface in a state where at least a portion thereof is buried in order to detect sloped land collapse,
An optical fiber disposed so that a part thereof is along a groove provided on the upper surface of the support in order to detect the presence or absence of movement of the support;
Deformation detecting means connected to one end of the optical fiber and detecting a deformation value and a deformation position of the optical fiber due to the movement of the support;
Inclined landslide detecting means for detecting an inclined landslide based on the detection result by the deformation detecting means and specifying the position thereof;
An inclined land collapse detection system comprising: The slope failure detection system according to claim 12,
The inner side surface of the groove along which the optical fiber extends has a curved surface having a predetermined curvature, and when the support column moves, the optical fiber receives tension and comes into close contact with the curved surface. An inclined landslide detection system, wherein the fiber is bent with the predetermined curvature. The slope landslide detection system according to any one of claims 12 to 13,
A slope landslide detection system, wherein a plurality of the columns are provided, and each part on the path of the optical fiber is arranged along a groove of the columns. The slope failure detection system according to claim 9 to 14,
The slope landslide detection means has a reference value, determines that slope landslide has occurred based on a comparison result between the deformation value and the reference value, and further calculates the position thereof. Detection system. The slope failure detection system according to claim 9 to 15,
The deformation detection means is an OTDR detecting system for outputting a reference pulse light to the optical fiber and receiving backscattered light generated based on the reference pulse light and output from the optical fiber. . A slope failure detection system according to claim 1 to 15,
The slope failure detection system according to claim 1, wherein the wavelength of the reference light is 1480 nm or more. The slope failure detection system according to claim 16,
The slope failure detection system according to claim 1, wherein a wavelength of the reference pulse light is 1480 nm or more. The slope failure detection system according to claim 1 to 18,
The inclined column collapse detection system, wherein the column has a shape with a curvature of 10 mm or more and 60 mm or less when tension is applied to the optical fiber along the column. The slope failure detection system according to claim 1 to 19,
The optical fiber is a single-mode optical fiber having a cutoff wavelength of 1260 nm or less, and an inclined land collapse detection system.

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