Analysis of relationship on critical-pile lengths of pile groups with similar settlement

To provide a reference for the basic optimization design of pile groups and the existing pile foundation reuse with the design of pile length for new pile, based on shear displacement method, a model of load and displacement on single pile head was established. A similar settlement principle of pile-group was proposed for the analysis of the relationship of the critical-pile length of pile group, and the calculation model for settlement of pile group by considering pile group effect was established. The validity of its pile-length relationship was verified by pattern function optimization method and the influences of different soil Poisson's ratios, pile spacing and pile elastic modulus on critical length of a pile group were analyzed. The results show that with the increase of long pile length, the length of short pile increases to a peak value and then decreases; as parameter values of soil Poisson's ratio, pile spacing and pile elastic moduli increase, the peak value of short pile length increases with different growth amounts. The cases show a significant decrease in relative error of slenderness between foundation piles in an unequal-length pile group compared to an equal-length pile group with the same total pile length. © 2016, Editorial Department of China Journal of Highway and Transport. All right reserved.