考虑不同程度竖向加速度影响的边坡位移分析

Displacement Analysis of Slope Stability Considering the Different Degrees of Vertical Acceleration

在地震诱发边坡失稳的稳定性分析中,为展示边坡动态破坏过程,常常使用永久位移的量化指标,而竖向地震动的影响一直是分析坡体永久位移时一个存在争议的问题。基于经典的Newmark法,采用竖向地震系数λ表示竖向地震惯性力作用程度,输入台站实测到的经典三大地震波形,对比不同程度竖向地震动对于边坡永久位移的影响,研究结果显示:考虑竖向地震荷载的存在对于边坡的影响尤为显著,考虑竖向地震系数λ为正时,最高可以达到不考虑竖向加速度永久位移的两倍之多;而分析不同大小坡度对于永久位移影响时,坡角较小的边坡容易产生更大的位移增长率。因此在抗震设计时,不可忽略竖向加速度对于边坡的影响。

In the stability analysis of earthquake-induced slope instability,in order to demonstrate the dynamic failure mode of slopes,quantitative indicators of the permanent displacement are often used.The influence of vertical ground motion on slope stability has always been a controversial issue when studying the permanent displacement of slopes.Based on the classical Newmark method,this paper uses the vertical seismic coefficientλto indicate the degree of vertical seismic inertial force,the classic three major seismic waveforms measured by the input station,and compare the effects of different degrees of vertical acceleration on the slope stability.It shows that the existence of vertical acceleration is particularly significant for the slope.Considering the vertical acceleration coefficientλis positive,it will have a significant impact on the stability of the slope,and the highest can be achieved without considering the permanent displacement of the vertical acceleration.When comparing the effects of different angles on slope stability,it is found that slopes with slower slopes are prone to greater displacement growth rates.Many times,so in the design of seismic slopes,the influence of vertical acceleration on the slope cannot be ignored.