To provide firstly a method for assuming consolidation yield strength based on the result of subsurface sounding tests (if consolidation yield stress can be determined here, consolidation deformation is determinable using the existing calculation formula), in substitution for consolidation tests, and secondly the allowable bearing force of ground if it consists of various different soil layers influenced by multiple soil layers below the bottom of foundation and upper and lower underground water surface layers.

For analyzing the degree of allowable ground stress, allowable bearing force is first of all calculated by a ground strength analysis method. In a ground deformation analysis method provided by this invention, settlement due to consolidation is calculated, assuming allowable bearing forces to be an external force, and the allowable bearing force in which soil deformation is below allowable settlement due to consolidation is adopted as an allowable degree of stress. If an allowable bearing force may cause deformation beyond the allowable settlement due to consolidation, this allowable bearing force is reduced and used as an external force to calculate settlement due to consolidation. The calculations are repeated until the value becomes lower than the allowable settlement due to consolidation, and thus the allowable degree of stress is determined.