This document provides information about experience and results of geotechnical modelling of the influence of reconstruction of the building of Perm Opera Theater which includes large extension of existing building with extensive underground part. These work is complicated by different problems like close location to existing buildings with historical value, need for using of underground space during the reconstruction, presence of the soft soils at the base of the existing building and high water table. Paper presents information about engineering solutions which enabled the successful fit into the strict requirements for additional settlements of historic buildings. Also paper presents conclusions which are made on basis of experience of this numerical modeling