Abstract
Ultimate bearing capacity of ground is an important subject in practical engineering, but the accuracy of Terzaghi's formula, which is widely employed in design, has not been clarified sufficiently. The problem of the formula is to employ a simple linear strength model into soils. The size effect in ultimate bearing capacity can't be evaluated in the formula properly. This paper develops a rigid plastic constitutive equation for soils the strength of which is non-linear against confining pressure. Higher order non-linear yield function is introduced into to express stress dependent soil strength adequately. The dilatancy property of soil is introduced into the constitutive equation by a penalty method to solve the boundary value problem explicitly with kinematical property. The applicability of proposed method has been examined through some case studies on ultimate bearing capacity analysis against vertical and inclined loads.
