JP2012088144A - Landslide observation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a landslide observation system capable of measuring a shear displacement in the ground and its direction without deriving a wire on the ground.SOLUTION: A landslide observation system includes: a cylindrical case body 11 to be embedded over a landslide clod C to be moved by the landslide, etc., and a foundation ground G not to be moved, i.e., over the shallower and deeper parts from a landslide surface; strain meters 20a, 20b arranged in the shallower part from the landslide surface in the cylindrical case body; strain meters 20c, 20d arranged in the deeper part from the landslide surface in the cylindrical case body; a landslide amount detector 25; an upper data output part for processing data of the strain meters 20a, 20b and transmitting the data to the ground; a lower data output part for processing data of the strain meters 20c, 20d and the landslide amount detector 25 and transmitting the data to the ground; and a data recorder 1 for receiving the data output from the respective output parts on the ground. At least the lower data output part includes: a transmission part for performing radio communication of measurement data by low-frequency electromagnetic wave; and a battery for power supply.

Description

  The present invention relates to a landslide survey for measuring shear deformation and the like in the ground using a borehole.

  For measuring the amount of movement of the landslide mass on the slip surface, a movement meter is used to derive a wire fixed at a certain depth in the ground and measure the amount of elongation of the wire (Non-patent Document 1).

  In addition, a pipe strain gauge that detects the bending strain of a strain gauge attached to a pipe is used for the purpose of determining the depth of the slip surface and the initial behavior of the landslide (Non-Patent Document 2).

"Landslide Observation Manual", pages 164 to 167, issued by the Japan Landslide Countermeasure Technology Association, October 1996 "Landslide Observation Manual", pages 135 to 145, issued by the Japan Landslide Countermeasure Technology Association, October 1996

  However, in the above movement meter, (a) the moving direction is unknown, (b) there is a period of dead zone immediately after the start of measurement, (c) the retaining tube is pulled up, (d ) When a wire is led out on the ground and the detection part of the displacement meter is placed on the ground surface, there is a problem that an error occurs due to contact between the hole wall and the wire due to hole bending or crushing outside the observation range shallower than the slip surface. . In addition, the above pipe strain gauge has the following problems: (a) the direction of movement is unknown, (b) the lead wire of the pipe strain gauge deeper than the slip plane is disconnected due to hole bending or crushing, making measurement impossible. there were.

  In order to solve the above problems, a landslide detection device according to the present invention includes a landslide amount detector that measures the amount of movement of a lump by a landslide without leading a wire to the ground, and a strain meter that senses the initial movement of a landslide on a landslide surface A cylindrical housing equipped with a means for recording the data of the landslide movement detector and strain gauge and transmitting it to the ground wirelessly is buried in the ground to be observed, and the amount and direction of landslide movement are measured.

  A landslide observation system according to an aspect of the present invention includes a landslide mass that is moved by a landslide and a non-moving basic ground, that is, a cylindrical housing that is embedded so as to cover a shallow portion of the landslide surface and a deep portion of the landslide surface, and the cylindrical housing. The data of the upper landslide detecting means arranged in the portion corresponding to the shallower portion than the landslide surface, the ground slip detecting means arranged in the portion corresponding to the deeper portion of the cylindrical housing than the landslide surface, and the data of the upper landslide detecting means. In order to process and send data to the ground, the upper data output unit arranged in the cylindrical casing and the data of the ground slip detection means to process and send data to the ground And a data recorder that receives data output from the upper data output unit and the lower data output unit on the ground. A monitoring system, the lower the data output unit, at least the lower data output section of the upper data output unit, a transmission unit for wirelessly communicating measurement data with a low frequency electromagnetic waves, comprising a battery for power supply.

  In the landslide observation system according to the aspect of the present invention, the upper landslide detection means and the ground slip detection means each include a plurality of strain gauges arranged at intervals in the circumferential direction of the cylindrical housing, and the upper data output Each of the unit and the lower data output unit detects the moving direction of the landslide from the position of the strain gauge in response to the deformation of the cylindrical housing caused by the landslide.

  In the landslide observation system according to the aspect of the present invention, the ground slip detection means further includes a landslide amount detector, and the landslide amount detector includes a displacement meter disposed deeper than the slip surface in the cylindrical housing. A wire having one end fixed to the shallower portion of the sliding surface in the cylindrical housing and the other end connected to the displacement meter, wherein the lower data output unit is a shear of the cylindrical housing detected by the displacement meter. The displacement is measured as the amount of landslide mass movement. Alternatively, the above-mentioned landslide detection means may further include a landslide amount detector. In this case, the landslide amount detector includes a displacement meter disposed in a portion shallower than the slip surface in the cylindrical housing, and one end fixed to a portion deeper than the slip surface in the cylindrical housing and the other end serving as the displacement meter. The upper data output unit includes a connected wire, and is configured to measure a shear displacement amount of the cylindrical housing detected by the displacement meter as a movement amount of the landslide mass.

  According to the present invention, it is possible to measure the shear displacement in the ground without leading the wire to the ground, and without making the measurement impossible due to breakage or crushing of the lead wire of the strain gauge deeper than the slip surface. It is possible to provide a landslide observation system that can measure the direction.

It is sectional drawing for demonstrating schematic structure of the landslide observation system by this invention. It is sectional drawing for demonstrating the detailed structure of the landslide observation system by this invention. FIG. 3 is a cross-sectional view taken along line AA in FIG. 2. FIG. 3 is a block diagram of an upper (or lower) detector shown in FIG. 2. It is a block block diagram of the measurement part shown by FIG. It is the figure which showed the example of data stored in the distortion amount table shown by FIG. It is the figure which showed the example of data stored in the slip amount table shown by FIG. It is sectional drawing for demonstrating the landslide detection operation | movement of the landslide observation system by this invention.

  Embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic sectional view showing an embodiment of a landslide observation system according to the present invention. In order to embed the landslide detection device 10 according to the present invention in the ground, drilling is performed by boring or the like, and the landslide detection device 10 is inserted from the ground and fixed at a predetermined depth. A grout such as cement bentonite is used for fixing the landslide detection device 10 and filling the hole. Data measured by the landslide detection device 10 is wirelessly transmitted to the ground and received by a data recorder (data receiving device) 1 disposed on the ground. Wireless data transmission preferably uses a low frequency magnetic field of less than 10 kHz, but is not limited thereto.

  In FIG. 1, a landslide observation system measures a landslide moving direction and a landslide amount, and wirelessly transmits these measurement data to the outside, and a data record for receiving a signal transmitted from the landslide detector 10. (Data receiving device) 1. The landslide detection device 10 is embedded in the ground where a landslide is to be observed, and the receiving device 1 is installed on the ground.

  The landslide detection apparatus 10 includes elements necessary for detection inside and outside a cylindrical housing, and the cylindrical housing is embedded so as to cover both a landslide mass C that moves due to a landslide and a non-movable foundation ground G. . That is, when the cylindrical casing is embedded, a boundary surface S between the landslide block C that moves due to landslide by boring or the like and the base ground G that does not move is found, and the intermediate portion of the cylindrical casing has the boundary surface S described above. It is buried to be located in. Therefore, in the landslide detection apparatus 10, the detection portion above the boundary surface S may be referred to as an upper landslide detection portion, and the detection portion below the boundary surface S may be referred to as a ground slip detection portion. Further, the underground above the boundary surface S can be referred to as a shallow part below the slip surface, and the underground below the boundary surface S can be referred to as a deep part beyond the slip surface.

  Referring also to FIG. 2, the landslide detection apparatus 10 includes a cylindrical housing 11 that is embedded with the long axis direction being directed toward the depth direction in the ground. The landslide detection apparatus 10 has the following configuration as means for detecting the landslide movement direction. A plurality of strain gauges 20 a, 20 b, 20 c, and 20 d are attached to the outer peripheral surface of the cylindrical housing 11 in the circumferential direction and in four steps. The inside of the cylindrical casing 10 above the middle portion in the long axis direction (that is, the portion corresponding to the boundary surface S) is connected to the strain gauges 20a and 20b above the middle portion in the long axis direction. An upper landslide detector 30a for detecting the direction of the landslide by processing the output from the strain gauge is installed. On the other hand, the inside of the cylindrical casing 10 below the middle portion in the long axis direction is connected to strain gauges 20c and 20d below the middle portion in the long axis direction, and processes the output from each strain gauge. A ground slip detector 30c for detecting the direction of the landslide is installed. In order to make the installation space of the upper landslide detector 30a and the lower landslide detector 30c a sealing space, an upper partition wall 13 and a lower partition wall 15 are respectively installed at the upper and lower portions in the cylindrical housing 11. As will be described in detail later, each of the upper landslide detector 30a and the lower landslide detector 30c has a function of wirelessly transmitting information indicating the detected landslide direction to the ground. The upper strain gauges 20a and 20b and the upper landslide detector 30a can be called an upper landslide detector and an upper data output unit, respectively, and the lower strain gauges 20c and 20d are displacements in the landslide detector 25 described later. Together with the total 26 and the wire 27, it can be called a base slip detecting means. On the other hand, the base slip detector 30c can be called a lower data output unit together with a measurement unit 40 described later.

  The landslide detection device 10 also has a landslide amount detector 25 built in the cylindrical housing 11. The landslide detector 25 includes a wire 27 having one end 27 a fixed to the upper partition wall 13, a displacement meter 26 that is connected to the other end of the wire 27 and detects the amount of extension as an extension, and an extension detected by the displacement meter 26. It has the measurement part 40 which transmits the information to show on the ground by radio. The wire 27 is stretched so as to have a constant tension between the displacement meter 26 provided in the upper partition wall 13 and the lower partition wall 15.

  An upper battery 50a for supplying operating power to the upper landslide detector 30a is built in the sealed space of the upper landslide detector 30a, and the lower landslide detector is located in the sealed space of the lower landslide detector 30c. 30c, and a lower battery 50c for supplying operating power to the measuring unit 40 is incorporated. The upper battery 50a and the lower battery 50c are disposed outside the upper landslide detector 30a and the ground slip detector 30c for convenience, but are included in the top landslide detector 30a and the ground slip detector 30c. May be.

  The cylindrical housing 11 is formed of, for example, a vinyl chloride pipe or the like, and both ends in the major axis direction are closed. The estimated landslide position 17 of the landslide detection device 10 is the length of the cylindrical housing 11 corresponding to the boundary surface S between the foundation ground G and the landslide mass C above it when the cylindrical housing 11 is buried in the ground. It is an intermediate position in the axial direction.

  On one end side of the cylindrical housing 11, that is, on the upper end when the cylindrical housing 11 is embedded, an upper sealing space 12 that houses the landslide detector 30a and the upper battery 50a is provided by the upper partition wall 13. The bottom slip detector 30c, the measuring unit 40, and the lower battery 50c are formed by the lower partition wall 15 on the other end side of the cylindrical casing 11, that is, the lower end when the cylindrical casing 11 is embedded. A housed lower sealing space 14 is formed. Between the upper sealing space 12 and the lower sealing space 14, a detection space 16 for forming a wire 27 of the landslide amount detector 25 is formed.

  The plurality of strain gauges 20a, 20b, 20c, and 20d are arranged at equal intervals in the circumferential direction on the outer peripheral surface below the upper sealing base 12 of the cylindrical housing 11 and above the assumed landslide position 17. A plurality of strain gauges 20a pasted and a plurality of strain gauges 20b pasted at equal intervals in the circumferential direction on the outer peripheral surface below and above the landslide device position 17, and a landslide assumption A plurality of strain gauges 20c attached to the outer peripheral surface below the position 17 at equal intervals in the circumferential direction, and further circumferentially on the outer peripheral surface below and above the lower sealing space 14 There are a plurality of strain gauges 20d attached at equal intervals. Here, the uppermost strain gauges 20a are upper group A strain gauges, the lower strain gauges 20b are upper group B strain gauges, and the lower strain gauges 20c are lower. A group C strain gauge is used, and the lowermost strain gauges 20d are called a lower group D strain gauge. In addition, in the following description, when it is not necessary to limit the group of a strain gauge, the code | symbol of a strain gauge may be set to 20 for convenience.

  As shown in FIG. 3, each group of strain gauges is composed of eight strain gauges arranged at equal intervals in the circumferential direction. Among the circumferential positions on the outer peripheral surface of the cylindrical casing 11, a specific circumferential position is set as the reference position 18. In the present embodiment, the reference position 18 is, for example, a position facing the “north” side when the cylindrical casing 11 is embedded in the ground, among the circumferential positions of the outer peripheral surface of the cylindrical casing 11. . One of the eight strain gauges is attached to the reference position 18 on the outer peripheral surface of the cylindrical housing 11. The remaining seven strain gauges are affixed on the outer peripheral surface of the cylindrical housing 11 in a line from the reference position 18 at equal intervals in the circumferential direction. In this embodiment, the number of the strain gauges 20 attached to the reference position 18 is 1, and the numbers of the strain gauges are 2, 3, 4,. Each strain gauge 20 is managed. Each strain gauge is a uniaxial strain gauge, and is affixed to the cylindrical casing 11 so that its detection axis is parallel to the long axis direction of the cylindrical casing 11.

  As described above, the landslide amount detector 25 includes the wire 27 and the displacement meter 26 to which the other end of the wire 27 is attached. The displacement meter 26 is fixed to the lower partition 15 on the lower sealing space 14 side of the cylindrical housing 11, and one end of a wire 27 extending from the displacement meter 26 to the upper sealing space 12 side is an upper partition wall on the upper sealing space 12 side. 13, the relative displacement amount of the end portion of the wire 27 with respect to the displacement meter 26 is measured.

  As shown in FIG. 4, the landslide detector 30a includes a computer 31, a communication device 36, a drive circuit 37 for the upper strain gauges 20a and 20b, a PC drive circuit 38 for supplying power to the computer 31 and driving it. It has a communication device drive circuit 39 for supplying power to the communication device 36 and driving it. The strain gauge drive circuit 37, the PC drive circuit 38, and the communication device drive circuit 39 are each connected to the battery 50a. Since the ground slip detector 30c has the same configuration, the description thereof is omitted. Here, it is assumed that the communication device 36 is of a type that wirelessly transmits data using a low-frequency magnetic field and includes a transmission antenna coil in both the upper-slip detector 30a and the lower-slip detector 30c. The low frequency magnetic field is used because the propagation state in the ground is preferable. In this case, the data recorder 1 also includes a receiving antenna coil that receives a low-frequency magnetic field signal, and has a function of extracting data from the received signal. However, the communication device 36 of the one closer to the ground, that is, the landslide detector 30a is not limited to wireless communication using a low-frequency magnetic field, and may be wired or batteryless.

  The computer 31 includes a CPU 32 that executes various processes, a ROM (Read Only Memory) 33 that stores programs executed by the CPU 32, a RAM (Random Access Memory) 34 that serves as a work area of the CPU 32, and the like. It has an interface circuit 35 for inputting / outputting data. In the RAM 34, a strain amount table 60 in which output values from the strain gauges 20a and 20b are stored is set.

  The slip amount table 60 of the background slip detector 30c will be described with reference to FIG. As shown in FIG. 6, the strain amount table 60 includes a strain gauge number area 61 in which the numbers or identifiers of the strain gauges 20c and 20d under the control of the base slip detector 30c are stored in advance, and an output from the strain gauge. It has a date and time area 62 in which the input date and time of values are stored, and a strain amount area 63 in which the output value for each strain gauge is stored as a strain amount for each input date and time.

  When the strain amount table 60 is the strain amount table in the ground slip detector 30c, the strain amount table managed by the strain amount table 60 is the strain gauges 20c and 20d of the lower groups C and D. In the strain gauge number area 61 of 60, the group identifier “C” or “D” added with the strain gauge number in the group is stored. That is, C1, C2, C3,..., C8, D1, D2, D3,..., D8 are stored in the strain gauge number area 61 of the strain amount table 60.

  Returning to FIG. 4, the strain gauge drive circuit 37 is a circuit that sends a current to the strain gauges 20 a and 20 b and acquires a change in the electrical resistance value accompanying the deformation of the strain gauges 20 a and 20 b. For this reason, the strain gauge drive circuit 37 includes a bridge circuit and an amplifier. Since the strain gauge drive circuit 37 of the upper landslide detector 30a acquires the change in the electric resistance value accompanying the deformation of all the strain gauges 20a and 20b constituting the upper groups A and B, all the strain gauges 20a and 20b are obtained. And a lead wire 21. Similarly, the strain gauge drive circuit 37 of the base slip detector 30 c is connected to all the strain gauges 20 c and 20 d constituting the lower groups C and D by the lead wires 21.

  Referring to FIG. 5, a measurement unit 40 includes a computer 41, a communication device 46, a displacement meter drive circuit 47 that drives the displacement meter 26, a PC drive circuit 48 that supplies power to the computer 41 and drives it, and a communication device. 46 has a communication device drive circuit 49 for supplying electric power to 46 and driving it.

  The computer 41 includes a CPU 42 that executes various processes, a ROM 43 that stores programs executed by the CPU 42, a RAM 44 that serves as a work area of the CPU 42, and an interface circuit 45 that inputs and outputs data to and from the outside. Yes. In the RAM 44, a slip amount table 70 in which an output value from the displacement meter 26 is stored as a landslide amount is set.

  As shown in FIG. 7, the slip amount table 70 stores a date / time area 71 in which the input date / time of the output value from the displacement meter 26 is stored, and a slip for storing the output value from the displacement meter 26 for each input date / time as a landslide amount. A quantity region 72.

  The displacement meter 26 and the displacement meter drive circuit 47 are connected by a lead wire 28. In addition, each drive circuit of the measurement unit 40 is connected to the lower battery 50c.

  Next, the installation procedure of the landslide detection apparatus 10 will be described.

  First, as shown in FIG. 1, a landslide detection point is bored, and a hole 8 having a diameter capable of embedding the cylindrical casing 11 is formed in the soil block C on the ground surface and the foundation ground G below the block C. Next, the landslide detection device 10 is inserted into the hole 8 so that the lower sealing space 14 side of the cylindrical housing 11 is located downward. Then, the orientation of the landslide detection device 10 and the reference position 18 (FIG. 3) of the cylindrical housing 11 are directed to “north”, and the expected landslide position 17 of the cylindrical housing 11 is located on the landslide surface S. After adjusting the depth, a grout 9 such as cement bentonite is filled in the gap between the inner surface of the hole 8 and the outer surface of the landslide detector 10. Thus, the installation of the landslide detection device 10 is completed.

  In the present embodiment, the output means to the outside, that is, the data recorder 1 is the communication device 36. The driving means for supplying power to the strain gauge 20 to drive them is a strain gauge driving circuit 37, and the driving means for supplying power to the output means to drive it is a communication device driving circuit 39. . The displacement output means for outputting the amount of displacement detected by the displacement meter 26 to the outside is the communication device 46. The displacement meter drive means for supplying power to the displacement meter 26 and driving it is the displacement meter drive circuit 47. The displacement meter drive means for supplying power to the displacement output means and driving it is driven by the communication device. Circuit 49.

  Next, the operation of the landslide observation system will be described.

  The output from each strain gauge 20 and the output from the displacement gauge 26 are always input to any one of the computers 31 and 41 of the upper slide detector 30a, the lower slide detector 30c, and the measuring unit 40. The CPUs 32 and 42 of the computers 31 and 41 have tables 60 and 70 in which output values (strain amounts) from the strain gauges and output values (slip amounts) from the displacement gauges 26 are set in the RAMs 34 and 44 at regular intervals. To store. Further, the CPU 32 stores the output value from each strain gauge 20 in the strain amount table 60 even when the output value from any one of the strain gauges 20 exceeds a predetermined deviation from the previous output value. To do. The CPU 42 also stores the output value from the displacement meter 26 in the slip amount table 70 even when the output value from the displacement meter 26 exceeds a predetermined deviation from the previous output value.

  The upper landslide detector 30a, the lower landslide detector 30c, and the computers 31 and 41 of the measuring unit 40 are configured to have a predetermined time after the data of the tables 60 and 70 are transmitted wirelessly last time, or the tables 60 and 70, respectively. When the number of records exceeds the predetermined quantity, the communication devices 36 and 46 are caused to transmit the data in the tables 60 and 70 managed by the computers 31 and 41 to the data recorder 1 on the ground side.

  Here, it is assumed that a landslide in which the soil mass C on the foundation ground G shifts to the “south” side occurs on the foundation ground G as shown in FIG. 8 from 01:13 to 22 minutes on August 16.

  In this case, in this embodiment, the outputs from the strain gauges 20 and the displacement gauges 26 before 01:13 on August 16 at the landslide start time are stored in the tables 60 and 70 at regular time intervals as described above. Is done. Specifically, as shown in FIG. 6 and FIG. 7, before 01:13 on August 16, each table 60, 70 has August 00 00: 00, August 16, 01:00. The output value from each strain meter 20 and displacement meter 26 for every hour is stored. However, the output values from the strain gauges 20 and the displacement gauges 26 at these times are almost zero because they are before the landslide start time.

  When the landslide begins, the output value from any one of the many strain gauges is more than a predetermined deviation from the previous output value at 01:14 on August 16 immediately after that. Therefore, in the strain amount table 60, as shown in FIG. 6, output values from each strain gauge are stored as strain amounts at 01:14 on August 16. After that, every time the output value from one of the strain gauges 20 exceeds a predetermined deviation from the previous output value between August 16 and 01:22 of the landslide end time, the amount of strain The table 60 stores output values from each strain gauge.

  When the soil mass C above the foundation ground G shifts to “south”, the output value from the strain gauge located above and below the landslide surface S that is the boundary between the foundation ground G and the soil mass C is It changes a lot. Specifically, the output values from the strain gauge 20b in the upper groove B and the strain gauge 20c in the lower group C vary greatly. For this reason, referring to the data in the strain amount table 60, the position between the upper group B strain gauge 20b and the lower group C strain gauge 20c, which is assumed to be the landslide surface S, is almost August 16 01. It can be grasped that a landslide occurred at 14 minutes.

  Further, as shown in FIG. 8, in the portion of the outer peripheral surface of the cylindrical housing 11, the portion above the landslide surface S and facing north is shrunk in the depth direction, and the portion above the landslide surface S and facing south Extends in the depth direction. On the other hand, in the part of the outer peripheral surface of the cylindrical casing 11, the part below the landslide surface S and facing north extends in the depth direction, and the part below the landslide surface S and facing south faces shrinks in the depth direction. For this reason, as shown in FIG. 6, among the total strain gauges 20 c constituting the lower group C below the landslide surface S, the strain gauges attached to the north-facing portion on the outer peripheral surface of the cylindrical housing 11. The output from “C1” 20c has a value of “+”, and the output from the strain gauge “C5” 20c attached to the south-facing portion of the outer peripheral surface of the cylindrical casing 11 is “−”. Value. Therefore, it is possible to grasp in which direction the landslide has occurred by referring to the strain amount table 60 and considering the positive / negative of the output from all the strain gauges constituting the group.

  By the way, even if the landslide starts, the output value from the displacement meter 26 does not immediately exceed a predetermined deviation from the previous output value, so the output value from the displacement meter 26 immediately after the start of the landslide is the slip amount table. 70 is not stored. For this reason, as shown in FIG. 7, here, the output value from the displacement meter 26 is the slip amount at 8:01:19 on August 16, 6 minutes after 01:13 on August 16, which is the landslide start time. Is stored in the slip amount table 70. Thereafter, every time the output value from the displacement meter 26 becomes a predetermined deviation or more with respect to the previous output value between August 16 and 01:22 on the landslide end time, An output value from the displacement meter 26 is stored.

  Thus, since there is a relatively large time lag between the landslide start time and the timing at which the output value from the displacement meter 26 is stored, the landslide start time with reference to the slip amount table 70 can be accurately grasped. I can't. In the present embodiment, this time lag occurs because the landslide amount detector 25 using the wire 27 that cannot detect the initial movement of the landslide is used as a detector for detecting the amount of landslide.

  Suppose that the upper part moves relative to the lower part of the cylindrical casing 11 in a horizontal direction by a dimension equal to or smaller than the diameter of the cylindrical casing 1 due to a landslide. In this case, in the landslide amount detector 25 using the wire 27, the wire 27, which extends in a straight line in the vertical direction within the detection stub 16 in the cylindrical housing 11, is merely inclined while maintaining linearity. There is no bending. For this reason, even if the upper part moves relative to the lower part of the cylindrical casing 11 in the horizontal direction, if the movement amount is equal to or smaller than the diameter of the cylindrical casing 11, the extension amount of the wire 27 is substantially equal. Does not change. When the landslide further progresses and the amount of horizontal movement of the upper part relative to the lower part of the cylindrical casing 11 exceeds the diameter of the cylindrical casing 11, the wire 27 is connected to the cylindrical casing 11 as shown in FIG. Since the sensor space 16 bends and extends in the detection space 16, the output value from the displacement meter 26 begins to change.

  As described above, since the landslide amount detector 25 using the wire 27 cannot detect the initial movement of the landslide and there is a dead zone period, the landslide start time and the output value from the displacement meter 26 are stored. A relatively large time lag occurs between the two. For this reason, as described above, the landslide start time cannot be accurately grasped even by referring to the slip amount table 70.

  Therefore, in this embodiment, a strain gauge sensitive to deformation of the cylindrical casing 11 is used, and the output value from this strain gauge is stored in the strain amount table 60 so that the landslide start time can be accurately grasped. ing.

  In the slip amount detection by the landslide amount detector 25 using the wire 27, the extension amount of the wire 27, that is, the output value from the displacement meter 26 is handled as the slip amount. However, when one end of the wire is fixed to the ground foundation G in the ground and the other end of the wire is attached to a displacement meter installed on the ground, if the ground surface rises or is buried due to a landslide, the displacement meter is mainly horizontal In addition to the amount of landslide, the amount of elevation of the ground surface, which is mainly a displacement in the vertical direction, or the amount of burial is output together, making it impossible to accurately grasp the amount of landslide.

  Therefore, in the present embodiment, one end of the wire 27 is fixed to the upper partition wall 13 of the cylindrical housing 11 while the other end of the wire 27 is fixed to the displacement meter 26 fixed to the lower partition wall 15 of the cylindrical housing 11. By attaching, the wire 27 does not stretch even when the ground surface is raised or buried, so that the amount of landslide can be grasped more accurately.

  Further, in the landslide detection apparatus 10 according to the present embodiment, the constituent elements for the upper landslide detector 30a are installed above the assumed landslide position 17 of the cylindrical housing 11, and the constituent elements for the base landslide detector 30c. In addition, main components for the landslide detector 25 are installed below the assumed landslide position 17.

  For this reason, in this embodiment, even if a landslide occurs at the landslide assumed position 17 where the probability of occurrence of a landslide is high, the lead wires 21 and 28 connecting the strain gauge and its drive circuit are not broken, The output value from the meter can be reliably output to the outside. Further, even if a landslide occurs at a position deviated from the assumed landslide position 17, specifically, for example, a landslide occurs at a position between the strain gauge 20c of the lower group C and the strain gauge 20d of the lower group D. Even if it occurs, there is a risk that the strain gauge existing between the actual landslide occurrence position and the assumed landslide position 17, that is, the lead wire 21 connecting the lower group C strain gauge 20c and its drive circuit may break. The other leads 21 and 28 are not broken only by being exposed. For this reason, in this embodiment, the breakage of the lead wires 21 and 28 can be minimized, and output values from more strain gauges can be output to the outside.

  As described above, the landslide detection apparatus 10 according to the present embodiment can detect a landslide direction, an accurate landslide amount, an accurate start time of landslide, and a landslide depth. Furthermore, in the landslide detection apparatus 10 of the present embodiment, it is possible to output the data from each strain gauge to the outside as reliably as possible by avoiding breakage of the lead wire connecting the strain gauge and its drive circuit. .

  In the present embodiment, one group is composed of eight strain gauges 20, but the present invention is not limited to this, and if three or more strain gauges are arranged at equal intervals. Any number of strain gauges may constitute one group.

  Moreover, in this embodiment, although the output value from eight strain gauges which comprise each group is output outside, computer 31 calculates | requires the landslide direction from each output value from eight strain gauges, Only this direction may be output to the outside, or this direction may be output to the outside together with each output value. As a method of obtaining the landslide direction from the output values from the eight strain gauges, for example, a strain gauge that outputs a positive maximum strain amount and a strain gauge that outputs a negative maximum strain amount are connected by a straight line. There are various methods, such as a method in which the vertical direction is the direction of the landslide.

  In this embodiment, output values from the strain gauge 20 and the measurement unit 40 are periodically stored in the tables 60 and 70. However, these output values are not stored in the tables 60 and 70 periodically. The output value may be stored only when the output value is greater than or equal to a predetermined deviation from the previous output value. Further, the output values may be stored in the tables 60 and 70 only periodically. In this case, since the time is not stored in the table 60 together with the output value immediately after the start of the landslide, the landslide start time cannot be accurately grasped, but the CPUs 32 and 42 have the output values from the strain gauge and the measurement unit. Since it is not always necessary to determine whether or not the deviation is greater than a predetermined deviation with respect to the previous output value, the load on the CPUs 32 and 42 is lightened, and the strain gauge and displacement gauge are always driven. Therefore, the power consumption of the upper landslide detector 30a, the lower landslide detector 30c, and the measuring unit 40 can be suppressed.

  In this embodiment, the output values from the strain gauge and the measurement unit are temporarily stored in the tables 60 and 70, and then the data stored in the tables 60 and 70 are output to the outside. The output value may be periodically output to the outside without being stored in the table.

  In the present embodiment, the measurement unit 40 and the background slip detector 30c are provided with computers 41 and 31, PC drive circuits 38 and 48, communication devices 45 and 36, and communication device drive circuits 49 and 39, respectively. These may be shared and used as the lower data output unit.

  In the landslide detection device according to the present invention, since both the wire and the displacement meter are arranged in the cylindrical housing, even if the landslide has a bulge or burial of the ground surface, the wire does not extend due to the bulge or burial of the ground surface. , Can accurately grasp the amount of landslide.

  In addition, it is possible to accurately grasp the landslide displacement direction without causing the strain gauge lead wire deeper than the slip surface to be broken due to bending or crushing of the hole and making measurement impossible. In this embodiment, a strain gauge and a displacement gauge are used as landslide detection means, and a technique for avoiding breakage of the lead wire is described. However, other landslide detection means such as a groundwater level gauge, a pore water pressure gauge, and an inclinometer are used. Needless to say, there are similar effects.

  Here, in the landslide detection apparatus, the output unit and the drive unit may be arranged in the cylindrical casing and above the displacement meter.

  Further, in the above embodiment, the landslide amount detector is configured at a deeper portion than the landslide surface of the cylindrical housing, but may be configured at a shallower portion than the landslide surface. In this case, the displacement meter 26 is installed in the upper partition 13 on the detection space 16 side, and the measuring unit 40 is installed in the upper sealing space 12. One end of the wire 27 is fixed to the lower partition 15, and the other end is connected to a displacement meter 26 installed in the upper partition 13. In this case, the upper strain gauges 20a and 20b are also referred to as a landslide detecting means together with the displacement gauge 26 and the wire 27, and the landslide detector 30a and the measuring unit 40 installed in the upper sealing space 12 are used as the upper data. Called the output section. On the other hand, the lower strain gauges 20c and 20d are called ground slip detectors, and the ground slip detector 30c is called a lower data output unit.

DESCRIPTION OF SYMBOLS 1 Data recorder 10 Landslide detection apparatus 11 Cylindrical housing 17 Landslide assumption position 18 Reference position 20, 20a, 20b, 20c, 20d Strain meter 25 Landslide amount detector 26 Displacement meter 27 Wire 30a, 30c Landslide detector

Claims (3)

A landslide mass that is moved by a landslide, etc., and a non-moving foundation ground, that is, a cylindrical housing that is buried so as to cover a shallow part of the landslide surface and a deep part of the landslide surface;
An upper landslide detection means arranged in a portion corresponding to a shallower portion than the landslide surface of the cylindrical housing;
A ground slip detection means disposed in a portion corresponding to a deeper portion than the landslide surface of the cylindrical housing;
In order to process the data of the above-mentioned landslide detection means and send the data to the ground, an upper data output unit arranged in the cylindrical housing,
In order to process the data of the base slip detection means and send the data to the ground, a lower data output unit arranged in the cylindrical casing,
A landslide observation system comprising a data recorder for receiving data output from the upper data output unit and the lower data output unit on the ground,
Of the lower data output unit and the upper data output unit, at least the lower data output unit is:
A transmitter that wirelessly communicates measurement data with low-frequency electromagnetic waves;
A landslide observation system comprising a battery for power supply. In the landslide observation system according to claim 1,
Each of the above-mentioned landslide detection means and the foundation slip detection means includes a plurality of strain gauges arranged at intervals in the circumferential direction of the cylindrical housing,
The landslide observation system, wherein each of the upper data output unit and the lower data output unit detects a moving direction of the landslide from the position of the strain gauge in response to the deformation of the cylindrical casing caused by the landslide. In the landslide observation system according to claim 1 or 2,
The above-mentioned landslide detection means or the above-mentioned base slip detection means further includes a landslide amount detector,
The landslide amount detector is
A displacement meter disposed at one end of the cylindrical housing;
Including a wire connected to the other end of the cylindrical housing and the displacement meter;
A landslide observation system that measures the amount of shear displacement of the cylindrical housing detected by the displacement meter as the amount of landslide mass movement.

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