双面加筋路堤的地震动力响应分析

Seismic response analysis of back-to-back mechanically stabilized earth(MSE) walls

双面加筋路堤作为加筋土挡土墙的一种衍生结构,沿袭了加筋土挡土墙优良的抗震性能,被广泛应用于道路建设工程,然而国内外关于双面加筋路堤的抗震设计还不够完善,采用的基于极限平衡法的抗震设计仍存在诸多问题。采用基于PLAXIS软件的有限元分析方法,对双面加筋路堤进行了较为全面的动力特性分析,结果表明,地震作用下双面加筋路堤的各层筋材最大内力分布、单侧面板侧移形式及路面沉降形式同单一的加筋土挡土墙表现形式相似;通过对不同宽高比结构筋材内力的分析得出,在地震作用下,加筋区及非加筋区之间存在第二潜在破裂面发育的可能。基于单自由度强迫振动理论及数值分析结果,建立了整体最大筋材内力与地震动及结构参数的关系。

The back-to-back mechanically stabilized earth(MSE)walls belong to a special type of geosynthetic-reinforced soil retaining walls.This type of walls are widely used in road construction projects that inherit the good seismic performance of GRS retaining walls,however,their seismic design methods at present are still not adequate.In this study,based on the calibrated PLAXIS finite element procedure,numerical simulations are carried out to investigate the seismic response of the back-to-back MSE walls.It is found that the back-to-back MSE walls show many similar dynamic characteristics with the GRS retaining walls when subjected to the earthquake loadings,including the maximum reinforcement loads,the residual lateral facing displacements and the settlements of backfill surface.There might exist a second failure surface from the analysis of the distribution of the reinforcement load in each layer.By fitting the numerical simulation results,it is also found that there exist good correlations among the maximum reinforcement loads,the input characteristics of earthquakes,and the frequency characteristics of structures.