Research on Engineering Characteristics of Negative Friction Resistance for Large-Diameter Caisson Pile

The negative frictional resistance for large-diameter caisson pile is very important to the stability of pile foundation. Lots of engineering projects speak volume for the signal influence of negative frictional resistance on foundation pile. Therefore, it is very necessary to analyze the generation mechanism of the negative frictional resistance on the large-diameter caisson pile and the mechanics characteristics for pile-soil in the coastal under consolidated soil environment. Base on the generation conditions and basic characteristics of negative frictional resistance, the generation conditions and generation mechanisms of negative frictional resistance for large-diameter caisson pile are analyzed on condition of under consolidation for saturated soft clay. Based on the linear softening model for the pile lateral face and hardening model for the tip of the pile, the analytical solution for negative frictional resistance based on the elastic theory was proposed. According to the one-dimensional consolidation theory, the analytical equations are attained when the pile-surrounding soil and pile-end soil is in different conditions. At last, the rationality of analysis process is verified by an engineering case.