Undrained bearing capacity of irregular T-bar by the lower bound method in clay

Abstract

The lower bound method is employed to investigate the ultimate bearing capacity of the irregular T-bar in uniform soil. The stress field is constructed to illustrate the evolution of the soil flow mechanisms and considering the frictional influence. Simultaneously finite element analyses and two special conditions are also employed to verify the reasonability of the lower bound model. The general expressions of the bearing capacity factors for two types of irregular T-bars are presented, which have reference value for similar ocean structures. The main results are shown as follows: ①The friction coefficients significantly influence the bearing capacity factor with increasing aspect ratio. ② The rigid zones are presented at the front and rear of the elliptical probe and progressively decrease with increasing ξ (probe aspect ratios) and reducing ω (friction factor), until disappearing at a larger aspect ratio following a smooth interface. ③ For ξ > 1, the degree of streamlining of the elliptical probe easily results in an attached flow mechanism to the probe surface and a decreasing rigid zone with increasing ξ in the high strength soil. ④ Compared with the CPT test, the advantage of the diamond T-bar is without the need for overburden stress correction in the full flow mechanism. ⑤ The large aspect ratio of the irregular T-bar tries to determine the interface friction factor based on the bearing factor equation.