Basic Principle of ultrasonic transmission method for detecting pile structure integrity

The basic principle of the ultrasonic transmission method for detecting the structural integrity of the pile body is: high-frequency Elastic Pulse Wave is triggered by the ultrasonic pulse emission source in the concrete, A high-precision receiving system is used to record the fluctuation characteristics of the pulse wave in the Process of concrete propagation. When a non-continuous or damaged interface exists in the concrete, the defective surface forms a wave impedance interface. When the wave arrives at the interface, the reflection, transmission, and refraction of the wave are generated, reducing the transmission energy. When serious defects such as loose, honeycomb, and holes exist in the concrete, the scattering and diffraction of waves are generated.

According to the characteristics of initial arrival time and wave energy attenuation, frequency variation and waveform distortion, the density parameters of concrete in the measurement area can be obtained. The test records the ultrasonic characteristics of different sections and heights. After processing and analysis, it can determine the nature, size, and spatial location of the internal defects of the concrete in the test area.

A certain number of acoustic tubes are embedded in the foundation pile as the channel of the transducer. During the test, each two acoustic tubes are in one group. The transmitter emits an ultrasonic pulse in one acoustic tube and receives the ultrasonic signal from the other acoustic tube. The two transducer must be horizontal. The instrument records the acoustic time, amplitude, and other acoustic parameters to determine whether the concrete between two acoustic measurement tubes is normal at this position. The receiving and transmitting transducer moves up from the bottom of the pile at the same time and detects the concrete integrity of the whole section point by point. The integrity of each section and even the whole pile can be obtained by testing all sections.