格宾加筋土挡墙抗震性能及数值分析

基于有限差分程序FLAC3D动力分析模块,建立水平地震作用下格宾加筋土挡墙足尺数值模型,通过抗震模型试验结果验证数值模型的可靠性,分析不同强度地震波作用、不同竖向加筋间距时,格宾加筋土挡墙的水平位移响应、震陷、加速度响应及破坏模式,在此基础上,提出格宾加筋土挡墙抗震设计相关措施与建议。结果表明:在不同峰值加速度作用下,格宾加筋土挡墙没有出现倒塌破坏,在较大的水平位移及沉降发生后仍能继续承载,表现出良好的抗震性能;在地震波频率特性基本不变的情况下增长加速度峰值,墙面加速度放大系数有减小的趋势;格宾加筋土挡墙建造于7度及以下、8度、9度及以上抗震设防区时,格宾网竖向间距分别不宜大于1.0m、0.75m、0.5m;水平地震作用下挡墙潜在破裂面为双线段组合形式;提出格宾加筋土挡墙抗震设计位移控制标准。

Numerical analysis of seismic behaviour of gabion-reinforced soil retaining wall

Numerical simulation using the dynamic analysis module of the finite difference software,FLAC3D,was conducted for a full-scale gabion-reinforced soil retaining wall subjected to horizontal seismic wave.The numerical model was validated by comparison between the numerical and the measured seismic experimental results.The dynamical responses of the retaining wall,such as horizontal and vertical displacement,acceleration and failure mode,were analyzed when the wall was subjected to seismic waves with different amplitudes and was reinforced with different vertical spacing reinforcements.On the basis of the above analysis,some measures and suggestions were proposed for the seismic design of gabion-reinforced soil retaining wall.The results show that no collapse occurs when the wall is excited by seismic wave with different peak value accelerations.The wall can continue to bear load even though large seismic-induced horizontal displacement and settlement have appeared.Therefore,the gabion-reinforced soil retaining wall may have good seismic performance.The acceleration amplification factor trends decrease with increase of the peak value acceleration when the frequency characteristics of input seismic time-history is almost unchanged.The vertical spacing of the gabion mesh reinforcement should not exceed 1.0m,0.75m,0.5m,when the wall is constructed in seismic regions of earthquake intensity less than 7 degree,equal to 8 degree,no less than 9 degree,respectively.The potential sliding surface is bilinear when the wall is under horizontal seismic wave.The seismic-induced displacement control standard is suggested for gabion-reinforced soil retaining walls.