水平受荷桩1g模型试验变形特性的相似分析

林海¹，雷国辉¹，徐林²，雷国刚²

(1. 河海大学 岩土力学与堤坝工程教育部重点实验室/岩土工程科学研究所，江苏 南京，210098；
2. 南京市水利建筑工程总公司一公司，江苏 南京，210036)

摘 要：针对水平受荷桩在不同的长径比和桩土刚度比条件下可以表现出刚性桩、半刚性桩或柔性桩变形特性的特点，运用刚性桩和柔性桩的临界桩长计算公式，结合相似原理，推导了重力加速度为1g条件下缩尺模型桩与原型桩的临界桩长相似比，与几何相似比进行对比，评判模型桩和原型桩的变形特性，分析桩身材料模量相似比与几何相似比对模型桩和原型桩变形特性相似性的影响，并通过有限元方法进行数值模拟验证。研究结果表明：桩身材料模量是控制模型桩与原型桩满足变形特性相似的主要参数；直接采用原型桩材和原型土开展的模型试验与原型桩的变形特性不具有相似性，但通过选择模量相似比接近于几何相似比的模型桩材可以使得模型试验结果与原型相似。

关键词：水平受荷桩；缩尺模型；刚性桩；柔性桩；相似性

Similarity analysis of deflection behavior of laterally loaded piles in 1g model tests

LIN Hai¹, LEI Guo-hui¹, XU Lin², LEI Guo-gang²

(1. Key Laboratory of Geomechanics and Embankment Engineering of Ministry of Education,
Geotechnical Research Institute, Hohai University, Nanjing 210098, China;
2. First Branch of Nanjing Water Conservancy Construction Corporation, Nanjing 210036, China)

Abstract:Under the condition of different length to diameter ratios and pile-soil rigidity ratios, laterally loaded piles can exhibit deflection characteristics of rigid piles, semi-rigid piles or flexible piles. These characteristics can be distinguished by using the computational formulae for the critical pile lengths of rigid and flexible piles. With the similarity principle, the similarity ratio of the critical pile lengths between reduced-scale model piles under 1g condition and prototype piles was derived. By comparing it with the geometry similarity ratio, the deflection behavior of model and prototype piles was estimated. On this basis, the influence of pile modulus similarity ratio and geometry similarity ratio on the similarity of deflection behavior between model piles and prototype piles was analyzed. In addition, numerical simulations with the finite element method were performed to verify the analyzed results. The results show that pile modulus is the major parameter controlling the similarity of deflection behavior between model piles and prototype piles. If prototype pile and soil materials are directly used in the model testing, the similarity of deflection behavior does not exist between the model and prototype piles. However, it can be approximately achieved by selecting a model pile material having a modulus similarity ratio close to the geometry similarity ratio.

Key words:laterally loaded pile; reduced-scale model; rigid pile; flexible pile; similarity