高速铁路桥梁桩基础竖向动荷载测试

Field Measurement of High-speed Train-induced Vertical Loads on Bridge Pile Foundations

高速列车在桥梁墩台基础上产生的动荷载是计算桩基础累积沉降的重要参数。系统地测试了不同车速和车型在桥墩不同部位引起的动位移、加速度及墩身动应变,得到了不同跨度桥梁基础的动荷载参数。结果表明:桥墩动力响应(动位移和加速度)从梁端、墩顶到承台顶衰减显著。动位移与轴重、基础与地基土的整体刚度密切相关。桥梁支座具有降低加速度的作用。桥跨长度越长,动荷载越大,动荷载幅值约为动荷载峰值的20%~30%。动荷载可以用正弦函数模拟,频率与列车行驶速度和车厢长度有关。上述结论可为高速铁路桥墩基础的设计和计算作为参考。

The high-speed train-induced dynamic loads on bridge pile foundations are very important parameters to compute the cumulative settlements of pile foundations.Dynamic displacements,accelerations and strains on piers induced by different speeds and typies trains were measured in field to obtain the dynamic loading parame-ters.The results indicate that：the dynamic response of piers （dynamic displacements and accelerations）de-crease from beam ends,pier tops to pile caps.Vertical dynamic displacements are related to the axle loads and the whole stiffness of pile foundations and soils.Supports have important function in decreasing the accelera-tions.The longer the bridge spans are,the larger the dynamic loads are.The amplitudes of dynamic loads are a-bout 20%-30% of the peaks of dynamic loads.The train-induced dynamic loads can be simulated by sine func-tions.Frequencies are related to the speed of train and the length of carriages.The results can provide reference for designing the pile foundations supporting high-speed railway.