摘要
为研究反倾岩质边坡在强震作用下的动力响应规律,以西藏自治区芒康县贡扎滑前边坡为原型,开展大型振动台模型试验。提出基于频率相似的动力相似设计理念。通过分析PGA放大系数研究强震作用下反倾岩质边坡动力响应的基本特征。根据试验宏观现象,揭示边坡的破坏过程,并结合Hilbert-Huang变换进行时频域分析。结果表明:(1)PGA放大系数在边坡坡表及内部表现出“高程效应”,在1/2高程以上的水平方向上表现出“趋表效应”,边坡表面外凸处的动力响应最强烈。(2)地震波幅值对边坡动力响应有明显影响,随输入波幅值增大,PGA放大系数呈递增趋势。在输入波幅值为0.2g时,边坡出现损伤,PGA放大系数下降。(3)地震波频率对边坡动力响应规律的影响与坡体自振频率相关,地震波频率越接近边坡自振频率,边坡PGA放大效应越显著。从坡内水平方向来看,PGA放大效应对高频率地震波激励更敏感。(4)Hilbert谱表明高程对能量有放大效果。随高程增加,边际谱累积能量的频率分量变丰富,累积损伤增加。本试验揭示典型反倾岩质边坡动力响应规律,为类似边坡的防治提供科学依据。
To study the dynamic response of anti-dip rock slope under strong earthquake,a large-scale shaking table model test was carried out using the Gongzha pre-slide slope in Mangkang County,Xizang Autonomous Region as the prototype.A dynamic similarity design concept based on frequency similarity was proposed.By analyzing the PGA amplification the prototype,the basic characteristics of the dynamic response of anti-dip rock slope under strong earthquake were studied.According to the macroscopic phenomenon of the test,the failure process of the slope was revealed,and time-frequency domain analysis was carried out using the Hilbert-Huang transform method.The results showed that:(1)the PGA amplification factor exhibited an"elevation effect"on both the surface and inside of the slope,and a"surface-trending effect"in the horizontal direction above 1/2 elevation.The dynamic response was the strongest at the convex part of the slope surface.(2)The amplitude of seismic wave had a significant influence on the slope's dynamic response.As the input wave amplitude increased,the PGA amplification factor showed an increasing trend.When the input amplitude reached 0.2g,the slope was damaged and the PGA amplification factor decreased.(3)The influence of seismic wave frequency on the dynamic response of the slope was related to the slope's natural vibration frequency.The closer the seismic wave frequency was to the slope's natural vibration frequency,the more significant the PGA amplification effect.Horizontally inside the slope,the PGA amplification effect was more sensitive to high-frequency seismic excitation.(4)The Hilbert spectrum indicated that elevation had an amplifying effect on seismic energy.As elevation increased,the frequency components of the cumulative energy in the marginal spectrum became richer,and cumulative damage increased.This experiment reveals the dynamic response characteristics of typical anti-dip rock slope and provides a scientific basis for the prevention and treatment of similar slopes.
作者
陈旭东
唐学武
王晨
郭明珠
李鹏飞
CHEN Xudong;TANG Xuewu;WANG Chen;GUO Mingzhu;LI Pengfei(Department of Urban Construction,Beijing University of Technology,Beijing 100124,China;Hunan Earthquake Agency,Changsha 410004,China;Institute of Geophysics,China Earthquake Administration,Beijing 100081,China)
出处
《防灾减灾工程学报》
北大核心
2025年第4期906-917,共12页
Journal of Disaster Prevention and Mitigation Engineering
基金
国家重点研发计划基金项目(2018YFC1505001)
湖南省地震局防震减灾科研课题(202408)资助。
