The sound wave probe tube is the passage through which the probe enters the interior of a cast-in-place pile during ultrasonic testing. It is an essential component of the ultrasonic testing system for cast-in-place piles. The way it is embedded within the pile and its arrangement across the pile's cross-section directly impact the testing results. Therefore, the layout and embedding method of the sound wave probe tube should be marked on the design drawings, and the quality of embedding should be strictly controlled during construction to ensure the smooth progress of the testing.

The selection of spiral acoustic sound tube materials is based on principles of high sound transmission rate, ease of installation, and low cost. Sound pulses are emitted from the transmitter transducer, passing through the coupling water to the interface between the water and the acoustic sound tube wall, then through the tube wall to the interface between the sound tube wall and concrete. After passing through the concrete, they must cross another sound tube's two interfaces to reach the receiver transducer.