地震荷载下唐家山滑坡动力响应特征及破坏机理研究
Research on dynamic response characteristics and failure mechanism of Tangjiashan landslide under seismic load
侯玮华 1董杉 1张奇华 1彭宇林 1张恒1
作者信息
- 1. 中国地质大学(武汉)湖北巴东地质灾害国家野外科学观测研究站,湖北武汉 430074
- 折叠
摘要
为分析北川唐家山滑坡地震动力响应特征和变形破坏机理,通过振动台模型试验和FLAC3D数值模拟开展研究.研究表明:地震作用下,中缓倾角顺层岩质边坡加速度响应表现出"高程效应"和"趋表效应".地震波加载频率达20～30 Hz时,坡面各测点加速度响应峰值和坡脚监测点加速度峰值的比值即PGA放大系数呈现显著递增趋势;加载不同振幅地震波,坡面各测点PGA放大系数均呈现递增趋势.坡体失稳表现出明显时间和空间上的差异性,具有多次滑动现象,出现层间错动的多个滑动面.地震作用下该类边坡的破坏模式主要为"拉裂-剪切-滑移"型,破坏过程主要分为层间结构面拉裂、松弛阶段,竖向拉裂缝形成阶段,结构面剪切阶段和整体滑移阶段.研究成果对进一步认识此类边坡动力稳定性影响规律具有一定参考意义,可为防灾减灾和抗震设计提供科学依据.
Abstract
In order to analyze the seismic dynamic response characteristics and deformation failure mecha-nism of Tangjiashan landslide in Beichuan county,the research was carried out through the shaking table test and FLAC3D numerical simulation.The findings suggest that the acceleration response of the bedding rock slope with low to middle inclination angles shows"the elevation effect"and"the surface effect"under seismic load.While seismic waves loaded at 20 to 30 Hz,the ratio of the peak ground acceleration(PGA)of each measurement point on the slope face to that at the slope foot reflects a noticeable growth.When seis-mic waves of different amplitudes are set,it could see a mounting trend in the PGA amplification factor for each monitoring point on the slope.The slope failure exhibits significant temporal and spatial differences.It produces with multiple slip failures and causes several sliding surfaces with staggered interlayer move-ments.It is concluded that the failure mode of this rocky slope under seismic load is mainly"tension-shear-slip",and that the failure process could be classified into several stages of tensile failure and relaxation failure of interlayer faces,vertical tension cracking,interlayer face shearing,and slid-ing of the entire slope along weak interlayers.The results are hoped to provide some inspiration for further research on the effect law of dynamic stability for such rock slopes and offer a scientific basis for disaster prevention and mitigation as well as earthquake-resistant design.
关键词
顺层岩质边坡/振动台试验/数值模拟/动力响应特征/变形破坏机理Key words
Bedding rock slope/Shaking table test/Numerical simulation/Dynamic response characteris-tics/Deformation failure mechanism引用本文复制引用
基金项目
国家自然科学基金面上项目(52079129)
出版年
2024
NETL
NSTL
万方数据