水平地震作用下双级加筋土挡墙损伤识别研究

Damage identification of two⁃tiered reinforced soil retaining wall under horizontal seismic loading

因对台阶式加筋土挡墙损伤识别的研究不足,开展了双级加筋土挡墙的大型振动台试验。采用时域识别方法分析了水平地震作用下模型的动力响应特征,阐述了上、下级挡墙自振频率、阻尼比的分布规律,探究了结构损伤程度与自振频率、阻尼比间的对应关系。研究结果表明:加载前上、下级挡墙的自振频率基本一致,阻尼比随墙高的增加而减小;随着加载工况的累积,自振频率逐渐减小,阻尼比逐渐增大。采用数学方法对自振频率和阻尼比分布曲线进行多项式拟合,对比分析可得:当自振频率减小0~15.41%、阻尼比增大0~299.35%时,结构处于基本完好阶段;当自振频率减小15.41%~18.92%、阻尼比增大299.35%~360.07%时,结构处于轻微破坏阶段;当自振频率减小18.92%~21.29%、阻尼比增大360.07%~398.21%时,结构处于中等破坏阶段;当自振频率减小21.29%~29.60%、阻尼比增大398.21%~532.99%时,结构处于毁坏状态。

In allusion to inadequate research on damage identification of multi-tiered reinforced soil retaining wall,a large shaking table test of two-tiered reinforced soil retaining wall was carried out.The time domain identification method was used to analyze the dynamic response characteristics of the model under horizontal seismic loading,and the distribution laws of the natural frequency and damping ratio of the upper and lower retaining walls were expounded.The corresponding relationship between the structural damage degree and the natural frequency and damping ratio was explored.The results show that the natural frequencies of the upper and lower retaining walls are basically the same before loading,and the damping ratio decreases with the increase of wall height.With the accumulation of loading conditions,the natural frequency gradually decreases and the damping ratio gradually increases.The distribution curves of natural frequency and damping ratio are fitted by polynomial method.The comparative analysis shows that when the natural frequency decreases by 0~15.41%and the damping ratio increases by 0~299.35%,the structure is basically intact.When the natural frequency decreases 15.41%~18.92%and the damping ratio increases 299.35%~360.07%,the structure is slight damage.When the natural frequency decreases by 18.92%~21.29%and the damping ratio increases by 360.07%~398.21%,the structure is in the middle damage stage;when the natural frequency decreases by 21.29%~29.60%and the damping ratio increases by 398.21%~532.99%,the structure is destroyed.