The low strain PIT testing is to use a hammer to hit the top of the pile, and receive the stress wave signal from the pile through a sensor attached to the top of the pile. The stress wave theory is used to study the dynamic response of the pile-soil system, demonstrate and analyze the measured speed signal and frequency signal, so as to obtain the integrity of the pile. This method is easy to test, and the testing speed is faster, but how to obtain a good signal and how to better analyze the integrity of the pile is the key to the detection work.
The sampling process is the key to obtaining the signal, and you should pay attention to the following during the test:
① Selection of test points. The number of test points is different depending on the pile diameter and test signal conditions. Generally, the pile diameter is required to be above 120cm and 3 to 4 points are tested.
②The choice of hammering point. The hammering point should be 20-30 cm away from the sensor, regardless of the pile diameter.
③Sensor installation. The sensor is installed according to the location of the selected test point. Pay attention to choosing the pasting method. Generally, choose paraffin wax, butter, plasticine and ensure that the pile head is dry and there is no water.
