地震作用下含软弱夹层顺层岩质斜坡动力响应的试验研究  

An experimental study of dynamic response of bedding rock slope with weak interlayer under earthquake

作　　者：王志颖 郭明珠[1] 曾金艳[2] 王晨[1] 刘晃 WANG Zhi-ying;GUO Ming-zhu;ZENG Jin-yan;WANG Chen;LIU Huang(Department of Urban Construction,Beijing University of Technology,Beijing 100124,China;Earthquake Administration of Shanxi Province,Taiyuan,Shanxi 030021,China)

机构地区：[1]北京工业大学城市建设学部,北京100124 [2]山西省地震局,山西太原030021

出　　处：《岩土力学》2023年第9期2566-2578,2592,共14页Rock and Soil Mechanics

基　　金：国家重点研发计划资助项目(No.2018YFC1505001)。

摘　　要：以青藏高原金沙江流域下归洼滑坡为原型,开展了含软弱夹层的顺层岩质斜坡振动台模型试验,基于斜坡峰值加速度PGA的放大系数和Hibert-Huang变换(Hibert-Huangtransform,简称HHT)时频特征分析地震作用下含软弱夹层顺层岩质斜坡动力响应规律。试验结果表明:斜坡在地震作用下表现出明显“高程效应”和“趋表效应”,PGA在坡表距离坡底1/4高度处、坡顶、软弱夹层处较大。随着输入地震动强度的增加,斜坡刚度逐渐降低,自振频率逐渐减小。当输入波幅值达到0.7g之后,斜坡发生开裂和结构变形。输入波幅值相同的情况下,PGA放大系数与高程呈正相关,同一测点随着输入波幅值增加,放大系数逐渐下降,不同输入波的类型和时间压缩比对斜坡动力响应影响差异较大。Hilbert谱显示,高程和软弱夹层对地震波能量有放大作用,高频部分的能量放大尤其明显。Hilbert边际谱表明,软夹层作用下高频部分的累积能量放大明显,在坡表距离坡底1/4高度处的测点能量突然增大,与加速度放大效应部分的结论类似;Hilbert边际谱显示,随着输入地震波幅值增加,高频部分和代表斜坡自振频率部分的累积能量逐渐降低,输入地震波主频部分的累积能量逐渐占据主导地位,表明斜坡逐渐损伤破坏,斜坡的模态特性逐渐消失。Taking the“Xiaguiwa”landslide in Jinsha River Basin of Qinghai-Tibet Plateau as prototype,the shaking table model test of bedding rock slope with weak interlayer was designed and carried out.The dynamic response of bedding rock slope with weak interlayer under earthquake is studied from the aspects of PGA amplification factor and HHT time-frequency characteristics.The results show that the slope exhibits obvious"elevation effect"and"surface effect"under the action of input seismic waves.The peak value of PGA was larger at the 1/4 height of the slope surface from the bottom of the slope,the top of the slope,and the weak interlayer.With the increase of the intensity of the input seismic waves,the slope stiffness and natural vibration frequency decrease gradually.When the input wave amplitude reaches 0.7 g,the slope cracks and structural deformation occur.When the input amplitudes are the same,the PGA amplification coefficient is positively correlated with the elevation,and the amplification coefficient decreases gradually with the increase of the input amplitudes at the same measurement point.The influence of different input wave types and time compression ratios on the slope dynamic response is significantly different.The Hilbert spectrum shows that elevation and weak interlayer amplify the energy of seismic waves,especially the high-frequency part.The Hilbert marginal spectrum showed that the weak interlayer could amplify the energy of the high-frequency part.Hilbert marginal spectrum indicates that the cumulative energy of the high-frequency part was significantly amplified under the influence of soft interlayer,and the energy of the measuring point at the 1/4 height of the slope surface from the bottom of the slope suddenly increased,which was similar to the conclusion of the acceleration amplification effect.The results of Hilbert marginal spectrum shows that with the increase of the amplitude of the input seismic wave,the accumulated energy of the high-frequency part and the part representing the natural

关 键 词：振动台试验 边坡工程 顺层岩质斜坡 软弱夹层 动力响应 HHT时频分析 

分 类 号：TU435[建筑科学—岩土工程]