不同形式桥墩基础的动静刚度模型试验研究

Model Test Study on Dynamic and Static Stiffness of Bridge Pier with Different Type of Foundations

桥梁检测是保证既有桥梁安全运营的重要手段,但不同于桥梁的上部结构,既有桥梁的桥墩基础一般埋置于地下,目前仍难以准确地对其病害及承载能力进行测试和评估。本文基于机械阻抗法及静载试验方法,分别开展了桥墩基础的静、动刚度的缩尺模型试验研究。试验测试了扩大基础、沉井基础、群桩-承台基础3种基础形式,根据每种基础形式的承载力设计了对比模型。对比桥墩基础静、动刚度试验结果可知,对于不同的基础形式,在低频范围内动刚度均能够较好地反映其承载能力特性。因此,使用动刚度法测试并评价既有桥梁基础的承载能力具有较好的适用性。

Bridge Inspection is important to ensure safe operation of existing bridges. Unlike the bridge superstructure,t he bridge foundation is embedded underground; therefore, it is difficult to accurately detect the defects and assess the health.Based on the mechanical impedance method and the static loading test,a scale model experimental study on thedynamic and static stiffness of bridge foundation was carried out. Three types of foundations, including spread footing foundation,caisson foundation and pile foundation,were designed and tested according to their bearing capacities.Through the comparison of the experimental results of the static and dynamic stiffness,the dynamic stiffness at low frequencies indicates the bearing capacity for different types of foundations.Therefore,the dynamic stiffness method is recommended to apply in testing and evaluating the bearing capacity of the existing bridge foundation.