Lateral load distributions on grouped piles from dynamic pile‐to‐pile interaction factors

Abstract

SUMMARYThe load distributions of the grouped piles under lateral loads acting from one side of the pile cap could be approximately modeled using the elasticity equations with the assumptions that the underground structure is rigid enough to sustain the loads, and only small deformations of the soils are yielded. Variations of the soil-pile interactions along the depths are therefore negligible for simplicity. This paper presents the analytical modeling using the dynamic pile-to-pile interaction factors for 2×2 and 2×3 grouped piles. The results were found comparative with the experimental and numerical results of other studies. Similar to others' findings, it was shown that the leading pile could carry more static loads than the trailing pile does. For the piles in the perpendicular direction with the static load, the loads would distribute symmetrically with the centerline whereas the middle pile always sustains the smallest load. For steady-state loads with operating frequencies up to 30 Hz, the pile load distributions would vary significantly with the frequencies. It is interesting to know that designing the pile foundation needs to be cautioned for steady-state vibrations as they are a problem of machine foundation. However, for transient loads or any harmonic loads acting upon relatively higher frequencies, the pile loads could be regarded as uniformly distributed. It is hoped that the numerical results of this paper will be helpful in the design practice of pile foundation.

Test study on thickness of soil layer at top of plate affecting uplift failure of the NT-CEPP

“…When NT-CEPP is under horizontal load at home and abroad, the bearing mechanism of NT-CEPP has not been put forward reasonably [11] . At the same time, if the group effect of the pile will occur when the space of the NT-CEPP is closer [12] . How much the minimum space is in order to avoid the group effect of the pile; when the pile group effect is unavoidable under the external objective conditions, what number of reduction factor should be used for calculating the ultimate bearing capacity of the pile, all of above problems are not fully demonstrated from the current theoretical achievements.…”