Prediction of Ultimate Bearing Capacity of Long-Term Loaded Piles

Abstract

To predict the ultimate bearing capacity of long-term loaded piles, the shortcomings of current empirical formulas of pile bearing capacity considering time effect are discussed. Based on the current research of the bearing capacity of static bearing piles in natural saturated clay, factors for the bearing capacity of long-term loaded old piles are analyzed. Then, based on analysis of the data from pile foundation bearing tests, the formula for calculating the ultimate bearing capacity of jacked piles considering the time effect and the current pile foundation technical code is proposed, in which the pile side resistance aging coefficient of pile side resistance is proposed, and some factors for the aging coefficient are discussed. Based on the experimental data, a method for calculating the parameters in the formula by using soil properties is proposed. The accuracy of the proposed method is verified by a field test. The results show that this pile side resistance aging coefficient can predict the bearing capacity of single pile under current code, increase the design value of the bearing capacity of old piles while ensuring safety. By using the undrained shear strength and plasticity index, the pile side resistance aging coefficient can be predicted.

Keywords

• old pile
• ultimate bearing capacity
• aging coefficient
• undrained shear strength
• field test