In this paper, the lateral limiting pressure on square pile groups in undrained soil is explored using two-dimensional finite-element modelling. A parametric study is conducted to assess the role of pile–soil adhesion, group size and pile spacing on group capacity and corresponding failure mechanisms. Results from the finite-element output show that large groups of closely spaced piles exhibit significant reductions in lateral capacity compared to equivalent single pile values. Significant variations in the load sharing across the group are also observed, with the corner piles experiencing loads up to 162% above the group average for a 25-pile group. A simplified closed-form design approach is developed using a modified Ramberg–Osgood formulation to predict the lateral group capacity. The proposed approach is shown to provide excellent agreement with the numerical results and a rigorous upper-bound prediction of a selection of field data and predictions determined using existing design guidelines.

中文翻译：

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不排水土壤中方形桩群的侧向极限压力

本文利用二维有限元模型研究了不排水土方桩群的侧向极限压力。进行了一项参数研究，以评估桩-土粘附力，桩组大小和桩间距对桩组承载力和相应破坏机制的作用。有限元输出的结果表明，与等效的单桩值相比，大群紧密排列的桩的侧向承载力显着降低。还观察到整个组的荷载分配有显着变化，对于25桩组，角桩承受的荷载比组平均水平高出162％。使用改进的Ramberg–Osgood公式开发了一种简化的封闭形式设计方法，以预测侧向承载能力。