The theoretical concepts used in the PYWALL software extend beyond the conventional method of analysis and design of flexible retaining walls based on limit-equilibrium theory. As a difference to conventional pratice, the PYWALL method includes the effects of soil-structure interaction.

Modern methods of analyses of the behavior of reatining structures consider realistic soil conditions and relevant details of the structural system. Therefore, a rational method of analysis and design must include the nonlinear soil-resistance-displacement relationships, pile spacings, penetration depths and structural properties. PYWALL considers soil-structure interaction by using a beam-column model and can analyze the behavior of a flexible retaining wall or soldier-pile wall with or without tiebacks or bracing systems.