Response of Single Piles in Marine Deposits to Negative Skin Friction from Long-term Field Monitoring

Abstract

The behavior of single piles subjected to negative skin friction in soft soil was conducted by analyzing the results from full-scale long-term field measurements and three-dimensional (3D) numerical analyses. A skin friction coefficient (α and β coefficients) of the instrumented piles is back-calculated at different degrees of consolidation (U) of soft marine clay. Back-calculated β-values ranged from 0.15 to 0.35 for clay, and from 0.30 to 0.55 for sand, respectively. In addition, back-calculated α-values ranged from 0.1 to 0.3 for coated pile, and from 0.2 to 0.8 for uncoated pile when undrained shear strength of the soft clay was about 30–60 kPa, respectively. Moreover, this study describes behavior of a pile based on full-coupled 3D finite element (FE) analysis. The appropriate parametric studies needed for verifying the pile-soil interaction with consolidation are presented in this paper. Compared to the results from the measurements, it is shown that the computed results are capable of predicting the pile-soil behavior under consolidation. The major parameters that influence the pile behavior are discussed for different soil-pile conditions.

Keywords:

• 3D FE analysis
• α and β coefficient
• degree of consolidation
• long-term and short-term analysis
• negative skin friction

Notes

Note. M.C. is Mohr-Coulomb model and S.S.C. is Soft soil creep model.

Note. M.C. is Mohr-Coulomb model and S.S.C. is Soft soil creep model.

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