A Sonic Pipe, also known as a Crosshole Sonic Logging (CSL) access tube, is a hollow steel or PVC tube installed inside bored concrete piles or diaphragm walls before concreting. Its main purpose is to provide an internal passage for sonic testing equipment to detect voids, cracks, or structural defects within the concrete.

In use, ultrasonic transmitters and receivers are lowered into the tubes to transmit sound waves through the concrete. Variations in wave speed and strength indicate inconsistencies or potential flaws in the pile integrity.

✅ Key Attributes:

• Smooth inner surface to optimize ultrasonic signal transmission

• Typically made of steel for durability and to withstand concrete pressure

• Installed in multiples along the pile cage, then filled with water before testing