JPH10122915A - Monitoring method and monitoring facility for ground displacement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a monitoring method and monitoring facilities for ground displacement, which are capable of being executed by simple configuration in relation to the measurement of the ground surface, and reducing the burden of cost and work compared with conventional method, and capable of realizing high precision measurement by simple configuration in relation to the measure ment of the inside of the ground. SOLUTION: In relation of the measurement of the ground surface, pulse signals are inputted to conductor wires 13, 14 laid near the ground surface through piles 12, and from the pulse signals and the reflected waves obtained by the pulse signals, impedances at the respective positions on the conductor wires 13, 14 are measured. In relation to the measurement of the inside of the ground, pulse signals are inputted to a first conductor wire arranged in a boring hole drilled in the ground, and from the pulse signals and the reflected waves obtained by the pulse signals, impedances at the respective positions on the conductor wire, are measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground displacement monitoring method and a monitoring facility for monitoring ground displacement.

[0002]

2. Description of the Related Art Conventionally, when measuring the displacement of the ground, a method of installing an inclinometer in the ground or measuring the displacement between several fixed points provided on the ground surface has been used. Was.

FIG. 6 illustrates a situation where a slope is monitored. In the figure, reference numeral 1 denotes a slope formed on the ground 2. The ground 2 includes a permeable layer 2a made of sand or the like,
It is formed by laminating an impermeable layer 2b made of clay or the like, through which water is difficult to pass. Further, it is assumed that a slip surface as indicated by reference numeral 4 occurs near the slope 1 in the permeable layer 2a.

When measuring displacement due to slip on the surface of the slope 1, as shown in the figure, fixed stakes 5, 5,... From these fixed piles 5, a piano wire 7, 7, ... is erected to an elongation measuring device 6 installed on the ground 2c above the slope 1. When displacement occurs on the slope 1, the displacement of the interval between the fixed piles 5 is obtained by measuring the elongation of each of the piano wires 7, 7,. Identify the area where slippage occurs.

If it is necessary to specify the slip surface 4, a boring hole 8 should be excavated in the slope 1 at the same time as the above measurement, and the displacement in the ground in the boring hole 8 should be measured. Is performed. In this case, specifically, an inclinometer is installed in the boring hole, thereby capturing the displacement of the ground 2, and a pipe having a strain gauge attached at an interval of 2 to 3 m is inserted into the boring hole 8. Thus, a rapid change in the ground generated on the slide surface 4 is captured.

Further, groundwater staying near the boundary 2d between the permeable layer 2a and the impermeable layer 2b tends to cause the ground 2 to slip. A water pressure gauge is inserted in 8 to observe changes in the groundwater level.

[0007]

However, when measuring the slope as described above, it is necessary to install a large number of piano wires 7, and for each of these piano wires 7, an elongation measuring device 6 is provided. Because of the necessity, there were problems in terms of cost and workability.

[0008] In addition, in order to measure the inside of the ground 2 in order to specify the slip surface 4, if an inclinometer is used, many expensive devices must be installed, and the ground is not necessarily required. There is a problem that it cannot always be installed at a location that coincides with the location of the occurrence of the sliding surface 4 in 2. Also,
Even when a method of inserting a pipe or the like into a borehole is used, it is difficult to accurately specify a sliding surface.

In view of the above, according to the present invention, the measurement of the ground surface can be performed with a simple configuration, and the burden on the cost and work can be reduced as compared with the related art. An object of the present invention is to provide a monitoring method and a monitoring facility for ground displacement that enable accurate measurement with a simple configuration to be performed inside the ground.

[0010]

Means for Solving the Problems In the present invention, the following means are employed in order to solve the above problems. That is, the ground displacement monitoring method according to claim 1 is a ground displacement monitoring method for monitoring ground displacement, wherein a lead wire is connected to a ground exposed portion of a pile arranged and placed on the ground. Erection, a pulse signal is input to the end of the conductor, a reflected wave from the conductor due to the input signal is detected, and an impedance at each position on the conductor is detected based on the input signal and the reflected wave. The displacement of the ground is monitored by measuring and observing the measurement result.

According to a second aspect of the present invention, there is provided a ground displacement monitoring method for monitoring ground displacement, wherein a conductive wire is disposed in a boring hole in the ground, and a ground side of the conductive wire is provided. A pulse signal is inputted from the end of the input signal, a reflected wave generated from the conductor caused by the input signal is detected, and an impedance at each position on the conductor is measured based on the input signal and the reflected wave. By observing the ground, the displacement of the ground is monitored.

A ground displacement monitoring facility according to a third aspect of the present invention is a ground displacement monitoring facility for monitoring a ground displacement, the pile being arranged at an interval with respect to the ground, A conducting wire erected on the ground exposed portion of the pile, pulse transmitting means for inputting a pulse signal to one end of the conducting wire, reflected wave detecting means for detecting a reflected wave from the conducting wire from one end of the conducting wire, and the pulse An impedance measuring unit is connected to the transmitting unit and the reflected wave detecting unit, and measures impedance at each position on the conductor.

A ground displacement monitoring facility according to a fourth aspect of the present invention is a ground displacement monitoring facility for monitoring ground displacement, wherein a boring hole excavated in the ground and a boring hole are disposed in the boring hole. A first conductor, a pulse transmitting means for inputting a pulse signal to a ground end of the first conductor, and a reflected wave from the first conductor from a ground end of the first conductor. A reflected wave detecting means for detecting, and an impedance measuring means connected to the pulse transmitting means and the reflected wave detecting means for measuring impedance at each position on the first conductor. .

A ground displacement monitoring facility according to a fifth aspect is the ground displacement monitoring facility according to the fourth aspect, wherein a second conductor is provided in the boring hole with an insulating material relative to the first conductor. The first conductor and the second conductor are inserted in parallel into groundwater stagnating in the borehole, and at the ground-side end of the second conductor, Receiving means for detecting a received signal obtained when a pulse signal is input to the first conductor is connected, and the receiving means is connected to the impedance measuring means.

According to the method for monitoring ground displacement according to the first aspect and the facility for monitoring ground displacement according to the third aspect, a conductor is erected on a pile driven into the ground, and a pulse signal is input to the conductor. By doing so, it is possible to measure the impedance at each position on the conductor. Further, when the conductive wire is extended, a change in impedance occurs, so that it is possible to detect the change. Therefore, when this is applied, for example, when slippage occurs on a slope, the slippage causes the distance between the piles to change at the same time, and the wire laid between these piles also extends. If attention is paid to the impedance of the conducting wire between them, it is possible to detect how the ground has been displaced.

In the ground displacement monitoring method according to the second aspect and the ground displacement monitoring facility according to the fourth aspect, a pulse signal is input to a conductor installed in a borehole, so that a pulse signal is input to the conductor. Since the impedance at each position can be measured, when a change such as the occurrence of slip occurs in the ground, the change can be detected as a change in impedance on the conductor.

Further, in the ground displacement monitoring facility according to the fifth aspect, one ends of the first conductor and the second conductor are inserted into groundwater, and the first conductor and the second conductor are inserted between the first conductor and the second conductor. Since the impedance can be measured, it is possible to detect a change in the groundwater level by focusing on the change in the impedance.

[0018]

An embodiment of the present invention will be described below with reference to the drawings. FIG.
FIG. 9 shows a diagram when applied to monitoring of behavior of “0”.
In the figure, reference numeral 11 denotes a ground displacement monitoring facility. The ground displacement monitoring facility 11 is a lead wire installed at the tip of a ground-exposed portion of piles 12, 12,. 1
3, 14, a measuring instrument 15 connected to each end of the conductive wires 13, 14, and a boring hole 16 provided in the middle of the slope 10.

The conductors 13 and 14 are each made of a conductive wire. The conductor 13 is parallel to the slope direction of the slope 10, and the conductor 14 is orthogonal to the slope direction of the slope 10. It is arranged.

FIG. 2 shows the details of the measuring instrument 15. As shown in FIG. 2, the measuring device 15 includes a pulse transmitting unit 17 and a reflected wave detecting unit 18 connected to the conductor 13 or 14, and an impedance measuring unit connected to the pulse transmitting unit 17 and the reflected wave detecting unit 18. 19 are provided.

The pulse transmitting means 17 can input a pulse signal to the conductive wire 13 or the conductive wire 14, and the reflected wave detecting means 18 can input the pulse signal to the conductive wire 13 or the conductive wire 13. The reflected wave generated in the conductor 14 can be detected. Further, according to the impedance measuring means 19, the impedance on the conductor 13 or the conductor 14 can be measured based on the input signal and the reflected wave.

FIG. 3 shows a situation in the vicinity of the boring hole 16. As shown in FIG.
6, a first conductor 21 and a second conductor 22 arranged in parallel via an insulating material 20 include an underground end 2 thereof.
1a and 22a are arranged in a state inserted into the groundwater 23. In addition, the first conductor 21 and the second conductor 2
2 is connected to the measuring device 24.

As shown in the figure, the measuring instrument 24 includes a pulse transmitting means 25, a reflected wave detecting means 26, and a receiving means 27.
And impedance measuring means 28. Among them, the pulse transmission means 25 is connected to the ground-side end 21 b of the first conductor 21, and can input a pulse signal to the first conductor 21. Further, a reflected wave detecting means 26 is connected to the first conductor 21 so that a reflected wave from the first conductor 21 accompanying the transmission of the pulse signal by the pulse transmitter 25 can be detected. . Furthermore, these pulse transmitting means 25
The reflected wave detecting means 26 is connected to the impedance measuring means 28 and is configured to be able to measure the impedance at each position on the first conductor 21 based on the input signal and the reflected wave. .

On the other hand, the insulating material 20
The receiving means 27 is connected to the second conducting wire 22 arranged in parallel via the second conducting wire 22, and receives an input signal to the first conducting wire 21 from the pulse transmitting means 25 from the second conducting wire 22. It is possible to do. Further, the receiving means 27 is connected to the impedance measuring means 28, and based on the input signal from the pulse transmitting means 25 and the received signal received by the receiving means 27, the first conducting wire 21 and the second conducting wire 22 It is possible to measure the impedance between them.

FIG. 4 shows a first conductor 21 and a second conductor 2.
2 is a diagram showing a cross-sectional structure of an insulating material 20. FIG. Thus, the first conductive wire 21 and the second conductive wire 22 are arranged on both side edges 20a of the insulating material 20 which is a long plate-like member. The first conductor 21 and the second conductor 22 are in a state where the coating is removed.

The main configuration of the ground displacement monitoring facility 11 according to the present embodiment has been described above. Next, occurrence of a landslide on the slip surface 30 in the ground 29 constituting the slope 10 is assumed. In this case, how the ground displacement is detected in the ground displacement monitoring facility 11 will be described.

When a landslide occurs on the slope 10 at a position represented by the slide surface 30, the position of the piles 12, 12,... Is displaced together with the slope 10 due to the landslide. However, since the installation position of the measuring device 15 is out of the range of the sliding surface 30 above the slope 10, the position of the measuring device 15 is not affected by the landslide.
Therefore, the conductive wire 13 installed between the measuring instrument 15 and the piles 12, 12,...

If a portion of the conductive wire 13 is stretched, the conductive wire 13 becomes difficult to conduct electricity, so that the impedance of the portion increases. Therefore, if a pulse signal is input to the conductor 13 by the pulse transmitting means 17 and a reflected wave generated by the pulse signal is detected and the impedance at each position on the conductor 13 is measured from the pulse signal and the reflected wave, the conductor 13 It can be determined at which position above the impedance has increased, that is, whether the extension has occurred.

Further, by using the pulse signal for the measurement of the impedance as described above, it is possible to accurately know at which position on the conductor 13 the elongation has occurred. In addition, each lead wire 1 between the piles 12, 12,...
By focusing on the elongation of No. 3, the position of the sliding surface 30 appearing on the slope 10 can be specified.

Further, by observing the impedance on the conductor 14 erected in a direction perpendicular to the direction in which the conductor 13 is erected, not only the inclination direction of the slope 10 but also the location where the slip surface 30 occurs in two dimensions can be determined. It becomes possible to specify. In addition, by arranging the conductors 13 and 14 in this manner, it is possible to observe a wide area of slip, and the observation range is widened as compared with a case where only one conductor is arranged. In the case where a partial collapse has occurred, there is a high possibility that this can be detected. Further, when a falling object is generated due to a partial collapse of the slope, if the falling object comes into contact with the conducting wire 14, the measured value of the impedance at the contact point increases, so that the position can be detected.

The action relating to the impedance as described above is also used when specifying the sliding surface 30 inside the ground 29. Sliding surface 3 inside ground 29
When a landslide occurs at 0, the first conductive wire 21 disposed in the borehole 16 is supposed to receive a strong shearing force in the vicinity of the sliding surface 30 to cause elongation or disconnection. As a result, at a position near the sliding surface 30 in the first conductor 21, the impedance rises. Therefore, based on the pulse signal from the pulse transmission unit 25 and the reflected wave from the first conductor 21 due to this pulse signal, the second impedance is increased. If the impedance at each position on one conductive wire 21 is measured, it can be easily detected that the sliding surface 30 has caused the slip at the place where the impedance has increased. Also, according to this method,
The position of the sliding surface 30 can be specified with extremely high accuracy (on the order of several centimeters).

Further, in the present embodiment, not only the position of the sliding surface 30 in the ground 29 can be specified as described above, but also the impedance between the first conductor 21 and the second conductor 22 is reduced. By being measured, it is often possible to ascertain groundwater fluctuations that cause slippage in the ground.

For example, in FIG. 3, when the water surface 23a of the groundwater 23 rises, the section of the first conductor 21 and the second conductor 22 buried in the groundwater 23 increases, and thus the first conductor 21 Since the electric capacity between the second conductor 22 and the second conductor 22 decreases, the impedance between them also decreases. Conversely, groundwater 23
When the water surface 23a of the first conductor 21 descends, the impedance between the first conductor 21 and the second conductor 22 rises.

Therefore, the pulse transmission means 25
When a pulse signal is input to the first conductor 21, the input signal is received from the second conductor 22, and the impedance between the first conductor 21 and the second conductor 22 is determined based on the input signal and the received signal. By observing the measurement result over time, it is possible to grasp a change in the position of the water surface 23a of the groundwater 23.

As described above, according to the ground displacement observation facility 11 of the present embodiment, the position of the sliding surface 30 appearing on the slope 10 is determined by moving the conductor 13 in the inclination direction of the slope 10. It becomes possible by laying one. Conventionally, in order to measure a sliding surface on a slope, many piano wires had to be installed on the slope, and measuring instruments corresponding to each piano wire had to be installed, In the present embodiment, since the above-described measurement can be performed with such a simple configuration, the observation of the slip on the slope can be reduced in cost and work load as compared with the conventional method. Can be planned.

Further, in the above embodiment, since the conductor 14 is laid in a direction perpendicular to the conductor 13 and the elongation of the conductor 14 is also measured, the two-dimensional and wide area sliding on the slope 10 is performed. The position of the surface 30 can be specified. In addition, by installing a plurality of conductors on the slope 10 in this manner, the observation range can be widened. In particular, as in the present embodiment, the conductors 14 extend in a direction orthogonal to the inclination direction of the slope. Is laid, it is possible to detect the position of a falling object caused by a partial collapse of the slope.

Further, the ground displacement monitoring facility 11 of the present embodiment performs the above-described high-precision identification of the position of the sliding surface 30 in the ground and monitoring of the level of groundwater that causes slippage as described above. There is an advantage that it is possible with a simple configuration.

The above is an example of the embodiment of the present invention, but the present invention is not limited to the above embodiment.

For example, the present invention can be used not only for measuring a slip surface on a slope as in the above embodiment, but also for measuring displacement on an arbitrary ground.

As shown in FIG. 5, the first conductive wire 21, the second conductive wire 22, and the insulating material 20 have a cross-sectional shape of the first conductive wire 21 formed in a tubular shape. The inside is filled with an insulating material 20 formed of a porous material, and a second conductive wire 22 is provided at the center of the insulating material 20.
May be arranged.

[0041]

As described above, according to the method for monitoring ground displacement according to the first aspect, a pulse signal is input to a conductor laid through a pile near the ground surface, and the pulse signal is obtained. By measuring the impedance at each position on the conducting wire from the reflected wave, when the distance between the piles is displaced, this can be detected from a change in the impedance. Therefore, unlike the conventional measuring method, there is no need to install a measuring device on the surface of the ground, and it is possible to detect the displacement of the ground with a simple configuration and a simple method. Furthermore, by arranging a plurality of such conductors, it is possible to detect displacement of the ground surface over a wide area, and it is possible to identify the position of a falling object on the ground surface depending on the arrangement of the conductors.

According to the method for monitoring ground displacement according to the second aspect, a pulse signal is input to a conductor disposed in a boring hole excavated in the ground, and the reflected wave is
By measuring the impedance at each position on the conductor, it is possible to detect displacement in the ground from a change in impedance. This method is particularly suitable for detecting the occurrence of a shear surface in the ground, and in that case, its position can be specified with extremely high accuracy.

According to the ground displacement monitoring facility of the third aspect, a pulse signal is input from the pulse transmitting means to the conductor laid on the ground via a pile, and a reflected wave accompanying the pulse signal is detected by the reflected wave detecting means. Since the impedance at each position on the conductor is measured from the input signal and the received signal, when the ground is displaced, the range is specified by focusing on the impedance of the conductor between the piles. It is possible. According to this facility, unlike conventional facilities, it is not necessary to install many measuring devices on the ground surface, and depending on the installation method of conductors, the location of a wide range of ground displacement and partial ground collapse can be determined. Accordingly, it is possible to specify the position of a falling object, and it is possible to easily reduce the cost of the measurement, reduce the work, increase the scale of the measurement, and increase the accuracy compared to the conventional facility.

According to the ground displacement monitoring facility of the fourth aspect, a pulse signal is input to the first conductor installed in the borehole in the ground by the pulse transmitting means, and the reflected wave is reflected by the pulse wave. Since the impedance at each position on the conductor is detected from the input signal and the received signal by the detection means, when the displacement occurs in the ground, the position can be specified with high accuracy. In particular, when a shear surface occurs in the ground, its position can be grasped more accurately than in conventional facilities, and therefore, the accuracy of detecting displacement in the ground and identifying the position is improved. Be improved.

According to the ground displacement monitoring facility according to the fifth aspect, the second conductor is disposed via the insulating material with respect to the first conductor, and the impedance between them is measured. By focusing on the change in impedance, it is possible to grasp the change in groundwater that causes landslide in the ground. Thus, according to this facility, it is possible to grasp the situation of the change in the groundwater level with a simple configuration.

[Brief description of the drawings]

FIG. 1 is a perspective view of a ground displacement monitoring facility according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a measuring instrument in the ground displacement monitoring facility shown in FIG.

FIG. 3 is an enlarged view showing the vicinity of a boring hole in the ground displacement monitoring facility shown in FIG. 1;

FIG. 4 is an enlarged sectional view of a first conductive wire, a second conductive wire, and an insulating material shown in FIG. 3;

5 is an enlarged cross-sectional view showing another embodiment of the first conductive wire, the second conductive wire, and the insulating material shown in FIG. 3, which is different from FIG.

FIG. 6 is a cross-sectional view of a slope showing a conventional technique of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Slope 11 Monitoring facility of ground displacement 12 Piles 13 and 14 Conductor 16 Boring hole 17 Pulse transmitting means 18 Reflected wave detecting means 19 Impedance measuring means 20 Insulating material 21 First conducting wire 21a Underground end 21b Ground end Reference Signs List 22 Second conductive wire 22a Underground end 22b Above ground end 23 Groundwater 25 Pulse transmitting means 26 Reflected wave detecting means 28 Impedance measuring means 29 Ground 30 Sliding surface

Claims (5)

[Claims] 1. A method of monitoring ground displacement for monitoring the displacement of the ground, comprising: laying a lead wire on an exposed portion of the ground of a pile arranged and laid on the ground, and attaching the lead wire to an end of the lead wire. A pulse signal is input to the input signal, a reflected wave from the lead wire due to the input signal is detected, and the impedance at each position on the lead wire is measured based on the input signal and the reflected wave, and the measurement result is observed. Monitoring the ground displacement by monitoring the ground displacement. 2. A ground displacement monitoring method for monitoring ground displacement, wherein a boring hole is excavated in the ground, a conductor is disposed in the boring hole, and a ground-side end of the conductor is provided. , A reflected wave from the conductor caused by the input signal is detected, and based on the input signal and the reflected wave, the impedance at each position on the conductor is measured, and the measurement result is observed. Monitoring the ground displacement by monitoring the ground displacement. 3. A ground displacement monitoring facility for monitoring ground displacement, comprising: piles arranged in a row at an interval with respect to the ground; and a lead wire laid on a ground exposed portion of the pile. A pulse transmitting means for inputting a pulse signal to one end of the conductor,
Reflected wave detecting means for detecting a reflected wave from the conducting wire from one end of the conducting wire, and an impedance measuring means connected to the pulse transmitting means and the reflected wave detecting means for measuring impedance at each position on the conducting wire; A ground displacement monitoring facility equipped with: 4. A ground displacement monitoring facility for monitoring ground displacement, comprising: a boring hole excavated in the ground; a first conductive wire disposed in the boring hole; Pulse transmitting means for inputting a pulse signal to a ground end of the conductor, reflected wave detecting means for detecting a reflected wave from the first conductor from a ground end of the first conductor, and the pulse A ground displacement monitoring facility comprising: impedance measuring means connected to transmitting means and the reflected wave detecting means for measuring impedance at each position on the first conductor. 5. The ground displacement monitoring facility according to claim 4, wherein a second conductor is disposed in the boring hole in parallel with the first conductor via an insulating material. One end of each of the first conductor and the second conductor is inserted into groundwater stagnating in the borehole, and a pulse signal is input to the first conductor at a ground-side end of the second conductor. A receiving means for detecting a reception signal obtained when the monitoring is performed, wherein the receiving means is connected to the impedance measuring means.