A method for non-destructive determination of anchoring position of coal mine anchor cable

Abstract

The present invention relates to a method for nondestructive testing of anchoring engineering quality, and in particular to a method for nondestructively determining the anchoring position of coal mine anchor cables. Ultrasonic detection technology is used, and the transmission of ultrasonic waves in the anchor cable is considered to be a simple harmonic wave. A model is established using a simple harmonic wave equation. During detection, ultrasonic waves are emitted at the free end of the anchor cable. By deriving and recording waveform images from a signal acquisition analyzer for comparative analysis, a more intuitive understanding of the anchoring effect of the middle section of the anchor cable can be obtained. In addition, the rock mass in the deep part of the coal mine is relatively hard and the boreholes in the surrounding rock wall are relatively small. This method does not destroy the original anchoring structure itself or affect its working performance. It is important to accurately grasp the position of the anchoring agent in the borehole of the surrounding rock wall where the anchoring effect is played. Since there may be gas outbursts in the coal mine, the acoustic wave detection of this method can play an explosion-proof role, which is of great significance for improving the anchoring quality of the tunnel surrounding rock.

Description

Technical Field

[0001] The invention relates to a method for nondestructive testing of anchoring engineering quality, in particular to a method for nondestructive testing of the anchoring position of a coal mine anchor cable. Background Art

[0002] As the mining depth of coal mines continues to increase, the support of tunnels becomes increasingly difficult. Anchor cables are a very important support tool in tunnel surrounding rock support projects. The safe and efficient mining of coal mines depends to a large extent on the anchoring function and anchoring effect of anchor cables.

[0003] Usually, the anchoring method of anchor cables in tunnel support is end anchoring. Since the rock mass in the deep part of coal mines is relatively hard, when anchor cables are anchored to the surrounding rock, the anchor cable end pushes the anchoring agent to the bottom of the surrounding rock borehole. In this process, due to the influence of the drilling quality and the extremely small borehole diameter, the anchoring agent roll is easily affected by the broken rock in the borehole during the pushing process and breaks, causing the anchoring agent to be unable to accurately anchor the end of the anchor cable, thereby shortening the effective length of the anchor cable, thereby affecting the support effect of the anchor cable. At the same time, it is currently impossible to intuitively grasp the actual anchoring position of the anchor cable during the anchoring process. Therefore, seeking a method to detect the anchor cable anchoring position to prevent the anchor cable anchoring position from deviating and affecting its support performance is of great significance to controlling the construction quality and safety of coal mine tunnel anchoring projects. Summary of the invention

[0004] The purpose of the present invention is to provide a method for non-destructively measuring the anchoring position of a coal mine anchor cable.

[0005] The object of the present invention is achieved by the following approach: a method for non-destructively determining the anchoring position of a coal mine anchor cable, the method comprising the following steps:

[0006] ① Connect the anchor cable as the detected component to the acoustic wave transmitter, and record the waveform image of the ultrasonic wave in the non-anchored state of the anchor cable in the signal acquisition analyzer by transmitting the acoustic wave to the detected component;

[0007] ② By transmitting sound waves to the anchor cable in the anchored state, the waveform image of the ultrasonic wave in the anchor cable anchored state is recorded in the signal acquisition analyzer;

[0008] ③ Export the recorded waveform image from the signal acquisition analyzer, and compare the change in waveform image amplitude when the ultrasonic wave propagates in the two media of anchor cable and anchor agent in the non-anchored state and the anchored state according to the two-dimensional coordinate system with the distance to the free end of the anchor cable as the horizontal coordinate and the relative displacement as the vertical coordinate. In the anchored state, the waveform amplitude will be significantly smaller than the waveform amplitude in the non-anchored state. The position of this band from the origin of the X-axis in the two-dimensional coordinate system is the anchoring position from the exposed end of the anchor cable.

[0009] Furthermore, in step ③, the anchor position is determined by considering the transmission of ultrasonic waves in the anchor cable as a plane simple harmonic wave, and the functional relationship of the two-dimensional coordinate system is based on the vibration equation Where x is the distance to the free end of the anchor cable, t is the time, u is the ultrasonic transmission speed, A is the amplitude, is a natural constant.

[0010] The present invention discloses a method for non-destructively measuring the anchoring position of coal mine anchor cables, which adopts ultrasonic detection technology, and considers the transmission of ultrasonic waves in the anchor cables as simple harmonic waves. A model is established using simple harmonic wave equations, and ultrasonic waves are emitted at the free end of the anchor cables during detection. By deriving and recording waveform images from a signal acquisition analyzer for comparative analysis, a more intuitive understanding of the anchoring effect of the middle section of the anchor cables can be obtained. In addition, the rock mass in the deep part of the coal mine is relatively hard and the boreholes in the surrounding rock walls are relatively small. This method does not destroy the original anchoring structure itself or affect its working performance. It is important to accurately grasp the position of the anchoring agent in the boreholes in the surrounding rock walls where the anchoring agent plays an anchoring role. Since there may be gas outbursts in coal mines, the acoustic wave detection of this method can play an explosion-proof role, which is of great significance for improving the anchoring quality of the tunnel surrounding rock. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0012] Figure 1 This is a schematic diagram of the installation of the device in the method of the present invention;

[0013] Figure 2 This is a waveform diagram of ultrasonic detection of the anchor cable in a non-anchored state in an embodiment of the present invention;

[0014] Figure 3 This is a waveform diagram of ultrasonic detection in the anchor cable anchored state in an embodiment of the present invention;

[0015] In the figure, there are signal acquisition and analysis instrument 1, acoustic wave transmitter 2, receiving sensor 3, signal line 4, and anchor cable 5. DETAILED DESCRIPTION

[0016] Example:

[0017] A method for non-destructively measuring the anchoring position of a coal mine anchor cable, the method comprising the following steps:

[0018] ① Such as Figure 1 As shown, the anchor cable 5 is connected to the acoustic wave transmitter 2 as the detected component, and the waveform image of the ultrasonic wave in the non-anchored state of the anchor cable 5 is recorded in the signal acquisition analyzer 1 by emitting acoustic waves to the detected component, as shown in FIG. Figure 2 As shown;

[0019] ② By transmitting sound waves to the anchor cable 5 in the anchored state, the waveform image of the ultrasonic wave in the anchor cable 5 in the anchored state is recorded in the signal acquisition analyzer 1, such as Figure 3 As shown;

[0020] ③ Export the recorded waveform image from the signal acquisition analyzer 1, and compare the change in the waveform image amplitude when the ultrasonic wave propagates in the two media of the anchor cable and the anchor agent in the non-anchored state and the anchor cable anchored state according to the two-dimensional coordinate system with the distance to the free end of the anchor cable as the horizontal coordinate and the relative displacement as the vertical coordinate. In the anchored state, the waveform amplitude will have a band that is significantly smaller than the waveform amplitude in the non-anchored state. The position of this band from the origin of the X-axis in the two-dimensional coordinate system is the anchoring position from the exposed end of the anchor cable.

[0021] The working principle of the present invention is that since the ultrasonic wave is transmitted by the anchor cable in the two states of anchoring and non-anchoring, the ultrasonic wave in the anchoring state will be transmitted from one medium to another during the transmission process, and the amplitude of the sound wave will change in this process. After one round trip, i.e. one cycle, the anchor position of the anchor cable can be determined by the changes in the waveform images in the two states.

[0022] In step ③, the anchor position is determined by considering the transmission of ultrasonic waves in the anchor cable as a plane simple harmonic wave. The functional relationship of the two-dimensional coordinate system is based on the vibration equation Where x is the distance to the free end of the anchor cable, t is the time, u is the ultrasonic transmission speed, A is the amplitude, is a natural constant.

[0023] For anchor cable detection in the anchored state, since the frequency and period of the ultrasonic wave are not affected by the propagation medium, the wave velocity and amplitude are affected. Therefore, after the sound wave propagates to the anchoring section, the amplitude and wave velocity of the sound wave will change. By comparing the waveform diagrams in the two output states, it can be seen that the amplitude of the waveform diagram within 3-4m from the exposed end of the anchor cable in the anchored state is significantly smaller than the waveform amplitude in the non-anchored state. After the ultrasonic wave propagates from the anchor cable to the anchoring section, the amplitude of the sound wave will decrease, thereby judging that the position where the anchoring agent takes effect on the anchor cable is 3-4m away from the exposed end of the anchor cable.

[0024] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be thought of by a person skilled in the art within the technical scope disclosed by the present invention without creative work should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope defined in the claims.

Claims

1. A method for non-destructively determining the anchoring position of a coal mine anchor cable, characterized in that: The method comprises the following steps: ① Connect the anchor cable as the detected component to the acoustic wave transmitter, and record the waveform image of the ultrasonic wave in the non-anchored state of the anchor cable in the signal acquisition analyzer by transmitting the acoustic wave to the detected component; ② By transmitting sound waves to the anchor cable in the anchored state, the waveform image of the ultrasonic wave in the anchor cable anchored state is recorded in the signal acquisition analyzer; ③ The recorded waveform image is exported from the signal acquisition analyzer. According to the two-dimensional coordinate system with the distance to the free end of the anchor cable as the horizontal coordinate and the relative displacement as the vertical coordinate, the change of the waveform image amplitude when the ultrasonic wave propagates in the two media of the anchor cable and the anchoring agent in the two conditions of the anchor cable non-anchored state and the anchor cable anchored state is compared. In the anchored state, the waveform amplitude will be significantly smaller than the waveform amplitude in the non-anchored state. The position of this band from the origin of the X-axis in the two-dimensional coordinate system is the anchoring position from the exposed end of the anchor cable; In step ③, the anchor position is determined by considering the transmission of ultrasonic waves in the anchor cable as a plane simple harmonic wave. The functional relationship of the two-dimensional coordinate system is based on the vibration equation Where x is the distance to the free end of the anchor cable, t is the time, u is the ultrasonic transmission speed, A is the amplitude, is a natural constant.

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