Analysis of Negative Skin Friction on a Single Pile Based on the Effective Stress Method and the Finite Element Method

Negative skin friction (NSF) of piles in recent filling or soft area is an important effect factor pile bearing capacity. Since field experiments on NSF are time consuming and it difficult to large surcharge loads experimental research, a unified calculation method positive/negative was established based the effective stress for investigation. The closed-form analytical solutions calculating corresponding plastic elastic state were derived respectively. Meanwhile, axial load single under different distribution forms deduced. verified by comparing with in-situ test. Furthermore, computer model, which finite element method, used study coefficient, consolidation time, pressure, drainage condition, pressure ratio location neutral point. results show that significant. coefficient increased from 0.05 0.4, position point rose 22%, drag shaft obviously increased. conditions relatively less, but they had great influence magnitude NSF. pressures, normalized maximum load, Fmax/p, good linear relationship ratio, n, slopes same.