JPH02190520A - Setting of degradation position of ground - Google Patents

Abstract

PURPOSE:To set up the degradation position of ground by a method in which AE sensors are set on both ends of a bar waves guide to transmit sound and buried in the ground to detect AE phenomenon. CONSTITUTION:AE sensors 2 are set on both ends of a waves guide made of aluminium bar, etc., having good sound transmittivity. The sensors 2 are connected to a micro computer D through an AE processor A. The guide 1 is penetrated into a pit 6 excavated to an estimated slide face C into the ground B, and the pit 6 is filled with sand 7, where acoustic emission generated from cracking or deformation in the ground is detected by the sensors 2 and a degradation position is estimated by arithmetic processing of arrival time difference of signals and sound speeds in the guide 1. The degradation position of the ground can thus be exactly estimated at low cost in a short time.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is designed to accurately locate the collapse position of a rock in civil engineering work where collapse of another mountain is expected, and to effectively carry out countermeasure work against rock collapse. This relates to a method for locating the location of ground failure to ensure safe construction and safe work.

(Prior art) Conventionally, the location of collapse of the ground has been determined using an insertable underground inclinometer,
Alternatively, a fixed underground inclinometer was used to measure the inclination of a pipe installed on another mountain, and the location of the collapse of another mountain was estimated based on the magnitude of this inclination.

(Problems to be Solved by the Invention) When measuring with an insertion type underground inclinometer, the pipe installed on the other mountain is deformed due to distortion of the other mountain, making it impossible to insert the inclinometer, making continuous measurement difficult.

In addition, fixed underground inclinometers are installed with the pitch of the slope determined with the precision required for measurement, which increases the number of slope needles to be installed and increases measurement costs.

The present invention has been proposed in view of the problems of the prior art, and its purpose is to quickly and accurately locate the location of rock collapse, and to The object of the present invention is to provide a method for locating the position of a ground failure, which allows a measuring device to be installed at a lower cost than a conventional meter.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the ground failure position locating method according to the present invention uses a wave made of a rod-shaped material with good sound transmission and having AE sensors attached to each end. A guide is buried in the ground where collapse is expected, and the collapse position is located by measuring the time difference between when an AE phenomenon is detected by the pair of AE sensors and the speed of sound traveling through the waveguide. It is composed of

(Function) According to the present invention, the acoustic emission phenomenon (AE phenomenon) in which sound energy is released due to cracks and displacements that occur inside the earth, can be suppressed by the acoustic emission phenomenon (AE phenomenon), which is a method for improving sound transmission buried underground. By detecting with each AE sensor attached to both ends of a waveguide made of rod-shaped material, the location of the collapse of the ground is determined from the difference in arrival time of AE, the speed of sound traveling through the waveguide, and the length of the waveguide. It is something.

(Example) The present invention will be described below with reference to the illustrated embodiments.

(1) is a waveguide made of a rod-shaped material with good sound transmission properties such as aluminum, iron, ceramic, glass fiber, etc. Both end surfaces are finished with flat surfaces, and the AF and sensor ( 2) are attached with screws (3), etc., and each AH sensor (2) is attached with a cable (4).
It is connected to the AE processing unit via.

Since the AE sensor (2) is installed underground and used, the sensor body, the attachment part of the cable (4), the connector of the cable (4), etc. are waterproofed. In the figure, (5) is the sensor protection tube.

Then, in the cutting work of another mountain (Bl), a hole is drilled until it reaches the slip surface C1 estimated from the results of a polling survey, etc., and the wave guide (]) is inserted into the drilled hole (6). , Mortar and sand (7) in the drilled hole (6)
etc., fill it sufficiently.

Therefore, acoustic emissions (AE) generated by cracks and displacements occurring inside the ground are detected by the AE sensors (2) installed at both ends of the waveguide (1).
(2), and each detection signal is sent to the E processing device.

Then, the E sensor (2) was connected to both of the above in the same AE processing unit.
(2) The arrival time difference of the detection signal and the waveguide (1
) is measured, and the length of the waveguide (1) is calculated using a microcomputer.
The collapse position of Bl can be assumed.

(Effects of the Invention) According to the present invention, as described above, AE sensors are attached to both ends of a waveguide made of a rod-shaped material with good sound transmission, and the waveguide is buried underground where collapse is expected. By detecting acoustic emissions (AI) caused by cracks and displacement inside the ground using the AE sensors at both ends of the waveguide, we can calculate the time difference between when the AH phenomenon is detected by the E sensors at both ends of the waveguide, and the By measuring and calculating the speed of sound traveling through the waveguide, the location of the collapse of the ground can be located, and construction work to prevent collapse of the rock can be carried out effectively and construction safety can be ensured.

Since the AE phenomenon occurs at a stage when the strain of the other mountain is small, the method of locating the collapse position of the other mountain using AE measurement according to the present invention can detect the slippage of the other mountain at an early stage compared to displacement measurement using an inclinometer or the like. The location can be determined.

Furthermore, according to the method of the present invention, the sensors used for locating the collapse position of the board are only 2WA AE sensors attached to both ends of the waveguide, which is different from the conventional fixed type sensor. It can be installed at a lower cost than underground inclinometers.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing the implementation status of one embodiment of the ground failure position locating method according to the present invention, FIG. 2 is a front view of a ground failure position locating device used in the method, and FIG. The figure is a partially enlarged view. Prisoner-AE processing device, (Bl-other mountain, (0-・estimated slip surface, (+)-waveguide, (2)...A
E-sensor agent Patent attorney Shige Okamoto 2 people Figure 3

Claims (1)

[Claims] A waveguide made of a rod-shaped material with good sound transmission, each with an AE sensor attached to each end, is buried in the ground where collapse is expected, and the pair of AE sensors detect the AE.
A method for locating a collapse position of a ground, characterized in that the collapse position is located by measuring the time difference between the times when the E phenomenon is detected and the speed of sound transmitted through the waveguide.