长江漫滩非对称荷载下基坑围护结构变形特性研究

Study on Deformation Behavior of Retaining Wall with Asymmetric Load in the Yangtze River Floodplain

以长江漫滩地层中某紧邻道路的明挖隧道深基坑为背景,通过现场测试与有限元分析,研究了非对称荷载对基坑开挖变形特性的影响规律。实测结果表明:由于临时道路路堤荷载与车辆动荷载作用,偏压一侧基坑围护墙体的侧向变形明显较大,同时另一侧基坑围护侧墙顶部有向基坑外偏移的趋势;两侧变形不对称程度相对较小,这与偏压荷载大小及其与坑壁的距离等有关;由于长江漫滩相软土具有显著的蠕变特性,故侧墙变形具有显著的时间效应。有限元计算表明,随着不对称荷载的增加及其与坑壁距离的减小,偏压侧墙体位移模式不变,但侧移量增加,非偏压侧顶部向坑外的偏移量亦增加,基坑两侧围护结构变形的不对称程度不断增大。

Based on a tunnel excavation close to a road in Yangtze River floodplain,the influence of asymmetric load on the retaining walls of two sides are studied by methods of field monitoring and finite element.The field results show that the lateral displacement of the retaining wall at the side with asymmetric load is larger than the other side,and the top of retaining wall of the other side move outwards.The deformation asymmetry on both sides is relatively small,which can be ascribed to the factors of the asymmetric load and the distance between the load and the retaining wall.The effects of time-space characteristics are found remarkable due to the creep characteristics of soft clay in Yangtze River floodplain.The results of finite element method indicate that the lateral displacement of the side with asymmetric load increases with the increase of the asymmetric load and the decrease of the distance,the extent of asymmetry of two sides increase as well.