Analysis of the mechanical response of an axially-loaded pile is a fundamental problem in geotechnical engineering. For relatively long piles (i.e., piles sufficiently long that base resistance may be neglected), pile load-settlement behavior is dominated by the relationship between soil-pile relative displacement and pile skin friction, generally referred to as the t-z curve. Previous investigators have performed analyses of pile load-displacement behavior using relatively simple numerical tools. However, due to assumptions of elastic pile behavior (which does not allow for yielding), smallstrain formulations, iterative solution schemes (which may fail to converge for large displacement levels), and other practical shortcomings, these methods may not be applicable for analysis of large-displacement problems. This paper discusses two approaches for implementation of the American Petroleum Institute (API)-recommended soil-pile interaction model (i.e., t-z curve) in FLAC. This software package has a robust formulation, which is suitable for analysis of large-strain problems with non-linear material behavior. Consequently, the numerical implementations described in this paper are able to overcome the difficulties encountered by other existing pile analysis methods. Additionally, this paper presents verification of each of the two implementations against the API-recommended t-z curve.