Method for non-destructive measurement and calculation of casting length of anchor bolt

Abstract

The invention discloses a method for the non-destructive measurement and calculation of the casting length of an anchor bolt, and particularly provides a method for achieving the non-destructive measurement and calculation of the casting length of an anchor bolt by calculating the functional relation between amplitudes and attenuation coefficients during the propagation of ultrasonic guided wavesin the anchor bolt in order to overcome the defects that the method for the non-destructive testing method based on the ultrasonic guided wave in the prior art is incapable of acquiring reliable results and the method itself is of no repeatability. The method comprises the following steps: using an anchor bolt which is completely identical with the anchor bolt to be measured and calculated as a reference basis; acquiring the characteristic indexes of the propagation of the guided waves in the casting part of the anchor bolt through the frequency scanning test and wave packet analysis of the ultrasonic guided waves under the preset testing conditions; and further carrying out the frequency scanning test on the anchor bolt to be measured and calculated under the same testing conditions, andcalculating according to the result of the wave packet analysis and the acquired characteristic index values to acquire the casting length of the anchor bolt. The invention further provides a method for the non-destructive measurement and calculation of the total length of an anchor bolt on the basis of the method. The method of the invention has the advantages of reliable principle, scientific and convenient calculation, simple implementing instruments, convenient installation and high accuracy of the measurement and calculation result. Therefore, the invention is particularly applicable in the field of engineering.

Description

technical field [0001] The invention relates to a method for non-destructive measurement and calculation of the pouring length of a bolt realized by using ultrasonic guided waves, and belongs to the field of non-destructive testing. Background technique [0002] Bolt pouring technology is widely used in mining and geotechnical engineering, and the construction quality of bolts directly affects the safety and stability of caverns or slopes. The length of the bolt, the length of the pouring section, and the length of the free section are important indicators in the evaluation of the construction quality of the bolt. However, the construction of the bolt is a concealed project. Conventional methods such as pulling tests and taking rock cores not only damage the components, but also cause damage to the components. It is difficult to effectively detect it, so the high-precision non-destructive testing of the quality of bolt pouring has become a hot issue in the design and constru...

AI Technical Summary

Problems solved by technology

There are at least five deficiencies in this method: one, the method uses a guided wave with a frequency greater than 2MHz

Guided waves at this frequency are very complex, and pattern recognition is extremely difficult, which has a great impact on the implementation of the method. Second, the method uses the wave velocity in the free anchor as a reference value, but the wave velocity in the grouted anchor is different from that in the free anchor. The wave speed in the method is not the same, and its reference value is not high; third, the method does not take into account the fact that the wave speed will change significantly with the change of the medium characteristics; fourth, the method does not describe the specific part of the bolt to be detected Whether it is the free section, the grouting section or the entire length of the bolt, the technical solution is not clear; 5. This method does not explain the contact surface effect caused by the contact between the sensor and the bolt, and does not even consider its effect on the detection of the bolt at all. influences

To sum up, the non-destructive testing of anchor bolts implemented according to this method cannot obtain reliable results, and even the method itself may not necessarily be reproducible

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