Cross hole sonic logging

Crosshole Sonic Logging (CSL, also known as Crosshole Acoustical Testing) checks the integrity of drilled shafts.

 

It normally requires steel or PVC access tubes installed during the construction of the drilled shafts. These tubes are usually attached to the reinforcement cage along the full length of the shafts. The cage is then lowered into the hole and the concrete is poured.

 

In CSL, the tubes are filled with water as an intermediate medium. The sound source and the receiver are lowered. The sound source–a transmitter emits an ultrasonic signal in one tube and the signal is sensed some time later by the receiver in another tube. Poor concrete between the tubes will delay or disrupt the signal. The engineer interprets data in the field and later reprocesses it.