We are estimating settlement under a very heavily loaded large mat. The subsurface conditions at the site consists of over-consolidated multy layers of sandy and silty materials. Using the Plaxix, the settlement is very excessive compared to conventional method(order of magnitude of three times). Plaxix calculates both elastic and consolidated settlements of cohesive materials and then add up. Should we consider both types of the settlement under the mat or not. Any case history experience on plaxix settlement analysis.