The Transient Dynamic Response method is probably the most advanced method of assessing the integrity of piled foundations. The system measures both the input force to a pile as well as the resulting velocity responses and operates in the time and frequency domain. This allows pile shaft properties to be evaluated in 3 dimensions.
The TDR2 system comprises two main elements, the data acquisition hardware and sophisticated windows based software package, purpose designed for ease of interpretation and reporting.
The acquisition unit is lightweight, portable and waterproof. It can operate up to 2 days on a single charge and can store over 700 results. Basic analysis can be carried out with the unit on site, including measurement of length, mobility and dynamic stiffness.
The TPAP software is used to transfer data from the TDR2 to a pc, carry out analysis of results and produce reports. The software includes two advanced interpretation modules:
The SIMUL simulation module is used both for predicting the expected TDR test result based on knowledge of the pile geometry and the soil conditions and for iteratively matching with real test results. The potential influence of geotechnical conditions on individual pile shafts can be assessed and the program is also a very useful tool for interpreting real results obtained on site. Theoretical and site response curves are presented together with details of soil parameters and pile dimensions.
The IMPRO impedance profiling module takes the simulation a step further, and by analysing pile shaft impedance responses from the real result with depth is able to produce a pile shaft cross section profile. The result obtained are easy to interpret and explain to the client. The impedance profile is presented together with cross section profile and details of soil parameters used.
