Sounding pipe bending phenomenon recognition method for foundation pile detection acoustic transmission method

Abstract

The invention belongs to the field of engineering measurement, and discloses a sounding pipe bending phenomenon recognition method for a foundation pile detection acoustic transmission method. The sounding pipe bending phenomenon recognition method comprises the following steps: by using a low-pass acquisition and broadband response and receiving technique, sequentially measuring real-time acoustic signals of different points of a longitudinal cross section so as to obtain a full cross section wave velocity variation diagram; performing Fourier transform on the acoustic signals so as to obtain a full cross section acoustic signal frequency domain diagram; calculating estimated characteristic frequencies of different points according to the wave velocity variation diagram and designed pile diameters; finding actual characteristic frequencies near the estimated characteristic frequencies of different points to the measured in the full cross section acoustic signal frequency domain diagram; and if the actual wave velocity of one area in the wave velocity variation diagram is remarkably deviated from a normal value, and the characteristic frequencies in the acoustic signal frequency domain diagram are still approximate to the estimated characteristic frequencies, determining that the area belongs to sounding pipe bending and is unrelated to foundation pipe quality. By adopting the sounding pipe bending phenomenon recognition method, problems which are hard to solve by using a conventional acoustic transmission method and are caused by pipe bending effects can be effectively solved, and engineering loss which can be caused by incorrect judgment and mal-judgment can be avoided.

Description

technical field [0001] The invention belongs to the field of engineering measurement, and more specifically relates to a method for identifying the bending phenomenon of an acoustic measuring tube used in the acoustic wave transmission method for foundation pile detection. Background technique [0002] During the process of ultrasonic waves passing through the concrete medium, the performance and structure of the medium itself will affect various acoustic parameters of the acoustic signal. At this stage, the acoustic parameters generally investigated in concrete quality testing include wave velocity, amplitude, frequency and waveform. [0003] Changes in the speed of sound waves: Sound waves travel at different speeds in concrete with different materials. In general, the denser the internal structure of the concrete medium, the higher the elastic modulus, and the lower the porosity, the higher the wave velocity of the sound wave and the strength of the concrete; , necking,...

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Problems solved by technology

[0008] In view of the above defects or improvement needs of the prior art, the present invention provides a method for identifying the bending phenomenon of the acoustic tube based on the pile detection acoustic transmission method, thereby solving the problem that the bending phenomenon of the acoustic tube cannot be identified in the prior art

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