PISA is an acronym for Program for Incremental Stress Analysis. A computer program developed for analyzing the deformation of geotechnical structures, PISA offers advanced modeling features which can simulate geotechnical structures such as dams, excavations, tunnels, retaining walls, etc. As well, PISA operates within the Windows environment, allowing the engineer to input necessary information with the aid of dialog boxes and the mouse. Source: http://www.pisa.ab.ca/