中文摘要：

软土地基对外部环境的变化非常敏感,附近堆载对高速铁路既有桥墩基础可能产生重大影响,必须加以控制。以某高速铁路典型桥墩为例,建立三维有限元模型,分析了实际情况下堆载对桥墩变位的影响,其结果与实测数据吻合良好;然后变化堆载与桥墩之间的距离,详细地分析了不同距离下堆载对桥墩群桩基础的内力和变位的影响。结果表明：堆载与既有桥墩的距离越远,堆载对桥墩桩基础的内力和变位的影响越小。当堆载距离d小于软土层厚度h的4倍时,随d/h的增加,桥墩水平变位下降迅速;当d/h〉4时,随d/h的增加,桥墩水平变位下降缓慢。堆载与桥墩之间的控制距离取决于堆载规模、软土厚度和埋深、桥梁上部结构正常工作条件下所能容许的最大水平变位。

英文摘要：

The distance between surcharge load and existing bridged pile foundation is an important factor affecting the internal forces and displacements in piles. 3-D finite element models are set up to implore the behaviors of a pile foundation in a bridge of a high-speed railway line in China due to surcharge load. The calculated results are in good agreement with the field results. The distances between surcharge load and existing bridged pile foundation are varied to study the internal forces and horizontal displacements in piles. The results indicate that the larger the distance is, the smaller the internal forces and horizontal displacements in piles are. When the distance d is less than 4 times the depth of soft clay h, the horizontal displacements of pile groups decrease linearly quickly with an increase in d/h; while d is larger than 4 times h, the horizontal displacements of pile groups decrease slowly with an increase in d/h. The suitable distance between surcharge load and existing pile foundation is determined with the maximum permissible displacement of the upper structures under normal operating conditions.