严寒地区高速铁路多跨简支梁桥下部结构变位试验研究

Experimental Study on Substructure Displacement of High Speed Railway Multi-span Simply Supported Girder Bridge in Frigid Area

对一座严寒地区高速铁路多跨简支梁桥在一个完整冻融循环周期的变位情况进行了定期测试和实时监测,分析了桥梁下部结构横向、纵向变位随季节性冻融循环的变化规律。分析结果表明:墩顶变位是由桥墩基础两侧含水率差异导致的,墩顶横向、纵向变位在冻融阶段内均表现出单向发展趋势,并于融化回落后期恢复至变位初始值附近,且土体冻结发展期及融化初期是墩顶变位发展及变化的主要时期;在墩高不大于20 m的情况下,墩顶横向、纵向变位幅值一般不会超过10 mm。

A periodic testing and long term monitoring were carried out on a whole freeze thaw cycle of high speed railway multi span simply supported bridge in frigid area,and the change laws of transverse and longitudinal displacements of piers with seasonal freeze thaw cycles were analyzed.The analysis results show that the displacement of pier top is caused by the water content difference at the two sides of foundation.The transverse and longitudinal displacements of pier top show unidirectional trends in a freeze thaw period and revert back to the initial value at the later stage of melting.The frozen soil development period and the initial period of melting are the main periods of development and change of displacement of pier top.The transverse displacement and longitudinal displacement amplitudes of pier top will not exceed10mm if the pier height is not more than20m.