สำนักเกษตร โรงเรียนชุมชนเกษตร

http://www.sensorcraft.com.sg/others/ndtpile.html

Sonic Pile Testing Method

Commonly known as Echo test, Pulse test, hammer test, Pulse-Echo Method (PEM), Pile Integrity Test (PIT), Impulse Response, etc. In the Sonic test, the top of the pile top is tapped with a lightweight plastic hammer and the reflected wave are recorded by a suitable computerized equipment. From the resulting signal, or reflectogram, one can determine both length and continuity of the pile. In its most basic form, the sonic test measures the time between the hammer trigger, and the reflected wave, to indicate the pile's length. this is very similar to the famous Newton's cradle "executive toy". The PET (Pile Echo Tester) from Piletest.com uses the Pulse-Echo method (PEM) for quick quality control of a large number of piles. The pile top is struck with a lightweight handheld hammer. The reflected wave is captured and analyzed by the PET's digital accelerometer to provide information regarding the length and shape of the pile. The PET is fully compliant to ASTM Sonic standard D5882.