ABSTRACT: The capacity of laterally loaded group piles are conventionally analyzed by simply reducing the lateral subgrade reaction of the soil, kh. The lateral subgrade reaction is reduced to 0.35 kh, when the piles center to center distance is at 3 pile diameter and linearly increases up to 1.0 kh when the piles center to center distance is equal or higher than 8 pile diameter. It seems there is no consideration to the thickness of the pile cap and magnitude of lateral movement of the piles on this conventional approach. By using 3D finite element geotechnical software, the effect of these two factors can now be investigated. This paper presents the study on the impact of those two factors on lateral capacity of group piles. The study reveals that when base friction of the pile cap and the passive pressure acting against the pile cap is neglected, the effects of the pile cap thickness against group lateral efficiency is marginal and can be safely neglected. The center to center pile spacing and the lateral movement of the piles do play important roles in the capacity of the laterally loaded piles. The greater the pile spacing the greater the lateral group efficiency, so does the lateral movement.

link to download full paper: http://www.ejge.com/2015/Ppr2015.1320ma.pdf