TZPILE implements the well-known method of soil-structure interaction, commonly called the t-z method, where t-z and Q-w curves are used respectively for load transfers in side resistance and end bearing. The t-z and Q-w curves can be internally-generated for both driven piles and drilled shafts with the input of information on the supporting soil and on the geometry of the pile.
Curves of short-term settlement as a function of applied loads are essential for some engineering computations; for example, when refined input is needed for the analysis of piles in a group. If a field-load test is performed, the computed curves can be "calibrated" by modifying input information to TZPILE to reach agreement with the experimental curves. The calibrated, site-specific curves can then be used with TZPILE to design the production piles, which may vary from the test piles in geometry and stiffness.