考虑冻土效应的桥梁桩-土动力相互作用研究现状与展望

Study on dynamic interaction between bridge pile and soil with permafrost effect:status and review

冻土和地震是我国西部高寒高烈度地区桥梁工程建设中主要面临的两大挑战。冻土区线路工程广泛采用桩基础桥梁,土体冻结后会显著影响地震作用下桩-土动力相互作用过程,给桩基础桥梁抗震分析带来困难。首先系统总结和分析了冻土对桥梁结构地震响应的影响、桩-冻土相互作用效应及其计算模型等方面的研究现状,进而对相关成果进行了科学分析。研究表明:冻土的存在对桥梁结构地震反应的影响是显著的,桩基础桥梁抗震设计中不考虑冻土效应是不合理的。目前还存在的问题包括:冻土区桥梁结构地震反应的研究中,未充分考虑冻土效应;现有桩-土相互作用模型无法有效应用于冻土领域;地震作用下桩-冻土体系相互作用机理及其破坏特征不明确。在此基础上,提出了考虑冻土效应后桥梁桩-土动力相互作用为今后需要重点研究的方向。

permafrost(frozen soil)and earthquake are two major challenges for the bridge construction in cold regions with high earthquake intensity in western China.Especially to the widely applied bridges with pile-foundation,the permafrost will significantly affect the pile-soil dynamic interaction process under the earthquake action,and bring difficulties to the seismic analysis.Previous studies have shown that the presence of permafrost had a significant impact on the seismic response of bridge structures,and it was unreasonable without considering the effect of permafrost in the seismic design of pile foundation bridges.It is reviewed that the effect on seismic response of bridges,frozen soil-pile interaction effect and its calculation model and so on.It is unreasonable that not to consider permafrost effect on seismic design of bridge with pile foundation.The problems in current researches are:(1)soil freezing effect has not been fully considered in the research of the bridge seismic response in frozen regions;(2)the existing pile-soil interaction model is rarely applied in permafrost;(3)the interaction mechanism and destroy characteristics of pile-soil system under earthquake are not clear.Based on these situations,some proposals are put forward for future researches.