JP2004045158A - Ground movement measuring system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ground movement measuring system for selecting a plurality of methods for positioning ground surface displacement based on ground movement information acquired from a GPS positioning instrument and other ground movement observing instruments installed on a ground surface in a landslide area. <P>SOLUTION: The ground displacement at each install point is analyzed by using GPS positioning based on positioning data acquired from a plurality of the GPS positioning instruments installed at a landslide ground A of an observed object. When landslide movement is small, accuracy is enhanced. When the landslide movement is large, a processing time is reduced. The landslide movement is surely and accurately observed by selecting a static GPS positioning method and a real-time kinematic GPS positioning method and implementing a GPS positioning analysis process according to the ground movement information acquired from one or a plurality of a ground clinometer, an extensometer, a strain indicator, a well clinometer, a well water level indicator and a hyetometer. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a ground deformation measurement system for detecting a landslide, and in particular, a plurality of positioning methods for a ground surface displacement based on ground change information obtained from a GPS receiver and a ground change observation device installed on a ground surface in a landslide area. The present invention relates to a ground deformation measurement system for selecting a method.
[0002]
[Prior art]
2. Description of the Related Art In recent years, in order to monitor the activity of a dangerous area where a disaster, for example, a large-scale landslide is likely to occur, various observation equipments are installed and a system for constantly observing is adopted.
[0003]
In view of the above, in the related art, a situation where a ground deformation observation device is installed in such a landslide-hazardous area is shown as an example in FIG. FIG. 2A is a plan view of the landslide ground A when the landslide danger area is viewed from above, and the landslide ground A is modeled and represented. FIG. 2B shows a vertical cross section of the landslide ground A. As shown in FIG. 1 (b), the landslide ground A to be observed has a slip surface B with respect to the surface of the landslide ground, and the upper area of the landslide ground A is a normal extension area. And the area below it is a compression area.
[0004]
In general, by measuring the ground deformation in the extension area and the compression area of the ground, the state of the landslide of the ground can be observed. Extensometers E1 and E2 are installed at the lower part, and inclinometers D1 and D2 are also installed. In the extensometer E1, a wire is stretched in the direction of the landslide between the landslide ground A and the landslide peripheral ground, and the expansion and contraction between two points on the ground surface of each lands is measured to grasp the state of the upper part of the landslide ground A. In the extensometer E2, a wire is stretched in the landslide direction between two points on the lower ground surface of the landslide ground A, and the state of expansion and contraction of the lower part of the landslide ground A is grasped. Furthermore, since the slope of the ground surface of the ground changes when a landslide occurs, inclinometers D1 and D2 are installed on the upper and lower sides of the landslide ground A, respectively. These instruments measure the movement of the ground surface of the landslide ground A.
[0005]
Further, when a landslide occurs, a slip occurs on the slip surface B of the landslide ground A with the immovable ground that supported the landslide ground A. Therefore, as shown in FIG. 1 (b), a plurality of boring holes H1, H2, H3 penetrating through the ground A at the time of landslide are provided, and the degree of bending of each boring hole is determined by an inclinometer or strain gauge. Measure the deviation. The number of the boring holes is appropriately selected according to the scale of the landslide. These instruments measure the movement of the landslide ground A using the slip surface B.
[0006]
In the landslide phenomenon, since the amount of rainfall is an important factor, the rainfall gauge R is installed on the surrounding ground to measure the rainfall. Further, depending on the ground, the degree of permeation of rainwater differs, so that a borehole water level gauge is installed in the boreholes H1 to H3 to measure the groundwater level of the landslide ground A. These instruments measure the trigger of the landslide, not the movement of the landslide surface A.
[0007]
By the way, an extensometer that observes the movement of a landslide surface is a high-precision one that can detect fluctuations of 0.1 mm or less. For example, when two points where measurement wires are stretched are displaced in parallel. Cannot measure the variation. For this reason, recently, a positioning method based on a global positioning system (GPS) has been used to measure the displacement of the ground at the installation location.
[0008]
Since displacements caused by crustal deformation, landslides, and the like are usually small, when GPS-based positioning is used to observe these ground deformations, an interference positioning method is exclusively used to obtain necessary positioning accuracy.
[0009]
The interference positioning method uses a phase difference of a carrier wave in a GPS reception radio wave, and can obtain a high accuracy of about 1 to 3 cm. The interference positioning method further includes two methods, a static method and a real-time kinematic method. Here, the static (hereinafter, referred to as ST) method performs GPS signal reception continuously for several tens of minutes to several hours at an observation point, and performs network average calculation between a plurality of observation points to achieve high accuracy ( The positioning result can be obtained (approximately 5 mm in continuous reception for about 4 hours).
[0010]
The real-time kinematic (hereinafter referred to as RTK) method receives GPS radio waves at a reference point and an observation point whose coordinates are known, and performs positioning of the observation point based on the base line length between the reference point and the observation point. Although it falls (about 2 to 3 cm), radio wave reception at the observation point can be completed in a short time (about 10 seconds).
[0011]
[Problems to be solved by the invention]
As described above, as a measuring instrument for measuring ground deformation, there is a measuring instrument that measures each of various types of physical phenomena. Each of these instruments has their strengths and weaknesses, so in order to detect landslide phenomena early, it is necessary to use several instruments in combination and judge the results of those instruments comprehensively. At present, humans make comprehensive assessments based on the individual observations obtained to determine whether there is a risk of landslides.
[0012]
On the other hand, as a method of measuring ground fluctuation by GPS, there are GPS positioning by ST method and GPS positioning by RTK method. When the ST method is applied to landslide observation, it can detect very small displacements with high accuracy, making it suitable for detecting initial ground movements. Since the radio wave needs to be received for a time, when the ground changes become active, the detection of the changes cannot be made in time. On the other hand, when the RTK positioning method is applied, the detection can be performed on the order of seconds, but the detection accuracy of the displacement is on the order of cm, and the occurrence of an initial minute displacement cannot be detected.
[0013]
Ground fluctuation phenomena such as landslides continue to be minute in the early stages of the landslide, and after a certain period of time, large fluctuations occur rapidly. Therefore, as a countermeasure against disasters, it is necessary to take steps such as detecting early minute fluctuations at an early stage and taking an alert state, and taking a protective action when the fluctuations become large. Therefore, as a countermeasure against landslide, accurate ground change information that can be measured with an accuracy suitable for a state of change due to landslide is required.
[0014]
In addition, since the movement of the landslide ground surface can be measured by the GPS, the movement of the slip surface cannot be known. Furthermore, when there is a sign that landslides become active due to a rise in the groundwater level, it is necessary to be alert beforehand even if the landslide surface does not change.
[0015]
Therefore, in consideration of the above situation, the present invention takes advantage of the characteristics of each measuring instrument used to observe the landslide ground, and appropriately selects a positioning analysis by a different method according to the state of the ground deformation. It is an object of the present invention to provide a system capable of comprehensively judging a change in a landslide ground and observing a change in the ground reliably and accurately in any change state.
[0016]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides a ground deformation measurement system for observing ground deformation in a landslide area, in which a ground displacement amount is determined based on positioning information obtained from a GPS receiver installed on the ground surface. There are provided processing means for performing positioning analysis processing, and control means for selecting positioning analysis by a different method included in the processing means in accordance with ground deformation information.
[0017]
Here, the processing means is based on the static GPS positioning method and the real-time kinematic GPS positioning method.
[0018]
The ground deformation information includes a ground displacement amount analyzed and processed by the processing unit, and further, any one of a ground inclinometer, an extensometer, a strain gauge, an inclinometer in a hole, a water level gauge in a hole, a rain gauge or It includes the measured values of the ground deformation observing instruments obtained from a plurality.
[0019]
The control means selects a static GPS positioning method for the analysis process when the displacement amount or the measured value of the ground deformation observation device included in the ground deformation information is equal to or less than a specified value, and When the measured value exceeds the specified value, the real-time kinematic GPS positioning method is selected for the analysis processing. This specified value is set to a value indicating that the ground deformation has entered the landslide risk area.
[0020]
Note that the GPS receiver and the ground deformation observation device are installed at a location away from the processing means.
[0021]
With the above configuration, the ground deformation observation system of the present invention can accurately and reliably grasp the ground deformation such as a landslide.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of a ground deformation measurement system according to the present invention will be described with reference to FIG.
[0023]
In the present embodiment, an accurate method of measuring the ground displacement by GPS is employed as one of the instruments for measuring the ground deformation. Two analysis processing methods are adopted as GPS analysis processing methods for ground displacement, and the characteristics of each analysis method and the characteristics of ground deformation are selected and used so as to match. In addition, conventional observation instruments are also used to select this analysis processing method, and the system is a comprehensive ground deformation measurement system.
[0024]
FIG. 2 shows an example of the overall configuration of the ground deformation measurement system according to the present embodiment.
[0025]
In one landslide ground A in the observation target area 1, a GPS antenna 5 and a GPS receiver 17 for GPS positioning are provided at each of at least three observation points to form an observation network required for ST positioning. Install. As this observation point, a place where the movement of the mass in the landslide ground A is active is selected. Further, in the vicinity of each observation point, a detector of a conventional ground observation instrument for physically detecting ground deformation, for example, a ground inclinometer 7, an extensometer 8, a strain gauge 9, an inclinometer 10, and a hole Some of the inner water level gauge 11, the detector of the rain gauge 12, and the like are installed as necessary.
[0026]
The signals from these GPS receivers 17 and the detection signals from the detectors of the ground deformation observation instruments are collected by the ground observation station 2 installed near these observation points, and the measured values measured here are: The data is transmitted to a remote ground monitoring station 4 by a data transmitter 6 using a radio or the like.
[0027]
A GPS reference station 3 used for RTK positioning is provided in a fixed place not affected by landslides. The GPS reference station 3 contains an antenna 13 for GPS positioning, a GPS receiver 18, and a data transmitter 14 for transmitting received data to the monitoring station 4.
[0028]
If the observation target area 1 is large, the ground observation stations 2 are installed as appropriate, 2-1 to 2-N.
[0029]
The ground monitoring station 4 includes a receiver 15 that receives measurement data from each of the observation stations 2-1 to 2-N and the reference station 3, and an analysis processing device that uses an electronic computer or the like that analyzes the measurement results and outputs the results. 16 are stored.
[0030]
FIG. 3 shows the configuration of the functions performed by the analysis processing device 16 of the ground monitoring station 4.
[0031]
The analysis processing device 16 includes a GPS analysis processing method selection unit 32, an ST analysis processing unit 33, an RTK analysis processing unit 34, and an observation result storage / output unit 35. The input from the positioning method specifying unit 36 is taken in.
[0032]
The ground deformation observation data acquisition unit 31 performs a process of acquiring GPS reception data from each of the ground observation stations 2-1 to 2-N and the GPS reference station 3 and measurement data from the ground deformation observation device. This acquired data is divided into data for GPS positioning and measurement data from observation devices such as an extensometer, a ground inclinometer, a strain gauge, a borehole inclinometer, a borehole water gauge, and a rain gauge.
[0033]
The ST analysis processing unit 33 and the RTK analysis processing unit 34 calculate the ground displacement from the acquired GPS reception data.
[0034]
In the GPS analysis processing method selection 32, the GPS analysis processing is selected in accordance with a selection procedure described below from the positioning value by GPS and the observation value of the observation instrument.
[0035]
The procedure for selecting the GPS analysis processing performed here is as follows.
[0036]
As described above, the processing of the ST analysis processing unit 33 takes a long time (about 4 hours) until a result is obtained, but the measurement accuracy is high (about 5 mm), and the processing of the RTK analysis processing unit 34 is slightly measured. It is characterized in that the accuracy is reduced (about 2 to 3 cm), but the time to obtain the result is short (about 10 seconds). Therefore, in a state where there is no particular abnormality, since the ground fluctuation is small, the ST analysis processing is performed. Then, when the ground displacement value exceeds a specified range determined as a dangerous range, it is selected for an RTK analysis process in order to be able to respond immediately to the change. This is in order to deal with the fact that, in general, ground deformation has a feature in which a small displacement appears slowly in the initial stage, but suddenly changes to a large displacement when the ground starts to move.
[0037]
On the other hand, when the measured value from the observation instrument is determined to be in the dangerous range, it can be estimated that the ground deformation has started. At this time, the GPS positioning method switches the selection from the processing of the ST analysis processing unit 33 to the processing of the RTK analysis processing unit 34 so as to immediately respond to the displacement that will occur. Among the ground movement observation instruments, the extensometer and the ground inclinometer, the strain gauge and the inclinometer in the hole, the water level gauge in the hole and the rain gauge are the same types of phenomena, and may be any one of them.
[0038]
When any abnormality of the ground deformation has subsided and the state returns to the stable state, the GPS positioning calculation is automatically returned from the processing of the RTK analysis processing unit 34 to the processing of the ST analysis processing unit 33. That is, when the displacement due to the GPS positioning becomes smaller than the specified value and the values of other measuring instruments also return to the safe range, the positioning analysis is returned to the processing of the ST analysis processing unit 33.
[0039]
Further, when the positioning is specified by the positioning specifying unit 36, the GPS analysis method can be selected in preference to the automatic switching.
[0040]
The result storage and output unit 35 stores these GPS positioning results and other observation results in a storage unit, and outputs the results to a display, a printer, a communication line, or the like periodically or upon request. At the time of output, in order to make the behavior of the ground deformation easy to understand, visualization such as graph display may be performed.
[0041]
FIG. 4 is a flow chart showing a method for switching the GPS analysis processing.
[0042]
The GPS reception data is acquired in the GPS reception data acquisition step S1, and the process proceeds to the positioning analysis step S2. In this step S2, the position of each observation point is analyzed by normal ST analysis processing. Here, since the received data used by the GPS positioning method is the same regardless of whether it is ST or RTK, both processes may be executed inside the system. In this case, from step S2, there is only a difference that the positioning analysis result with the identification of which analysis process is performed is output approximately every 4 hours in ST and approximately every 10 seconds in RTK. .
[0043]
Further, there is an effect that, when the ground deformation is activated, the displacement amount with higher accuracy can be acquired at the time when the ST positioning analysis result is output, while acquiring the result of the RTK positioning analysis in real time.
[0044]
After continuing this analysis at a specified time interval, the displacement amount of the positioning analysis result is obtained in step S3. When it is determined that the displacement amount of the positioning is smaller than a specified value at which there is a danger of ground deformation, a request for selecting ST analysis processing is issued, and it is determined that the displacement amount of the positioning is larger than the specified value. At this time, a request for selecting the RTK analysis processing priority is issued, and the process proceeds to step 6 for determining the next positioning method.
[0045]
On the other hand, acquisition of ground deformation observation data is performed in step S5, and if this observation data indicates a dangerous range, the displacement of the ground surface may increase rapidly, so that the responsiveness of positioning is improved. In step S4, a request for selecting the RTK analysis process is given, and if it indicates a safe range, a request for selecting the ST analysis process is given. The request is sent to step S6 for determining the positioning method.
[0046]
Also, a request to select a GPS analysis processing unit at the discretion of the user is accepted in step S7, and this request is also sent to step S6 for determining a positioning method.
[0047]
In step S6, the positioning method is determined to be the one with the highest priority from among these positioning method selection requests, and the process returns to step S2 to perform analysis using the determined positioning method.
[0048]
As a criterion for the selection request of the positioning method in step S6, for the purpose of early warning, the displacement amount by the GPS positioning exceeds the specified value, or the ground deformation observation value exceeds the specified value, or the user selects one of the following. When there is a request for RTK analysis processing, the RTK analysis processing is selected, and when both the displacement amount by GPS positioning and the ground deformation observation value return to normal values, the ST analysis processing is selected. .
[0049]
As described above, the procedure of steps S2 to S7 is periodically repeated at a cycle determined in a cycle.
[0050]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, it can be set as the system which can continuously monitor from a small ground change to a rapid ground change by a GPS positioning method, and can perform early warning and evacuation judgment. In addition, as an analysis processing method for GPS positioning, an appropriate GPS analysis processing method can be selected according to the characteristics of a landslide where signs of change appear slowly at an initial stage and collapse at a stretch when the change expands. Of the ground can be accurately and reliably grasped. In particular, it is a system that enables more comprehensive monitoring by linking it to the initial minute fluctuations that cannot be captured even by static positioning, the movement of the slip surface, and the measured value of the landslide trigger.
[Brief description of the drawings]
FIG. 1 is a diagram showing a state of installation of a conventional ground deformation observation device.
FIG. 2 is a diagram showing an overall configuration of one embodiment of the present invention.
FIG. 3 is a diagram showing a configuration of a function implemented in the analysis processing device.
FIG. 4 is a flowchart showing a method for selecting a GPS analysis process.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Observation target area 2 ... Ground observation station 3 ... GPS reference station 4 ... Ground monitoring station 5, 13 ... GPS antenna 6, 14 ... Data transmitter 7, D1, D2 ... Ground inclinometer 8, E1, E2 ... Extensometer 9 ... Strain gauge 10 ... In-hole inclinometer 11 ... In-hole water level meter 12, R ... Rain gauge 15 ... Data receiver 16 ... Analysis processor 17,18 ... GPS receiver A ... Landslide ground surface B ... Landslide ground slide surface H1 , H2, H3 ... boring holes 31 to 36 ... processing blocks S1 to S8 ... processing steps

Claims (8)

Processing means for performing GPS positioning analysis processing on the amount of ground displacement based on positioning information obtained from a GPS receiver installed on the ground surface;
A ground deformation measurement system including a control unit that is included in the processing unit and selects a positioning analysis by a different method in accordance with ground deformation information. 2. The ground deformation measurement system according to claim 1, wherein the processing unit includes a unit based on a static GPS positioning method and a unit based on a real-time kinematic GPS positioning method. The ground deformation measurement system according to claim 1, wherein the ground deformation information includes the ground displacement amount analyzed by the processing unit. The ground deformation measurement system according to any one of claims 1 to 3, wherein it is determined whether the ground displacement amount is based on a static GPS positioning analysis process or a real-time kinematic GPS positioning analysis process. . The ground deformation information may further include a measured value of a ground deformation observing instrument obtained from one or more of a ground inclinometer, an extensometer, a strain gauge, a borehole inclinometer, a borehole water gauge, and a rain gauge. The ground deformation measurement system according to claim 1, wherein: The control means selects the static GPS positioning method for the analysis processing when the displacement amount included in the ground deformation information and the measurement value of the ground deformation observation device are equal to or less than a specified value, and the displacement amount or The ground deformation measurement according to any one of claims 3 to 5, wherein the real-time kinematic GPS positioning method is selected for the analysis processing when the measured value of the ground deformation observation device exceeds a prescribed value. system. The ground deformation measurement system according to claim 6, wherein the specified value is set to a value indicating that the ground deformation has become active or active. The ground deformation measurement system according to any one of claims 1 to 7, wherein the GPS receiver and the ground deformation observation device are installed at a location separated from the processing unit and the control unit.

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