水平与竖向加速度-时程曲线叠加效应下边坡永久位移计算的极限上限分析

实际边坡动力稳定性受地震竖向与水平方向效应共同作用,传统边坡地震永久位移计算方法较少考虑竖向地震波影响,采用实际地震的竖向与水平方向加速度-时程曲线共同效应更符合工程实际。基于极限分析上限法和Newmark刚塑性滑块模型,提出一种基于实际水平向与竖向地震加速度-时程曲线的边坡永久位移计算改进方法,以3个工程边坡为例,探讨了两组具有代表性实测典型水平和竖向地震地面运动记录对边坡地震永久位移计算的影响。研究结果表明:不考虑竖向地震加速度时程曲线时,本文方法可蜕化为与前人方法兼容;不同地震波的竖向与水平地震动时程曲线的叠加效应不同,竖向地震对边坡永久位移的影响不可忽略。

Upper bound analysis of seismic permanent displacement of soil slopes based on horizontal and vertical acceleration time-history curves

The dynamic stability of slopes is influenced by the horizontal and vertical earthquake forces. The traditional method of calculating the seismic permanent displacement does not take enough consideration about the vertical seismic effect. However, considering the combined effect of horizontal and vertical accelerations is more accord with the engineering practice. Based on the upper bound limit analysis and the model of Newmark''s rigid-plastic block, an approach for evaluating the permanent displacement of slopes based on the actual horizontal and vertical earthquake acceleration time-history curves is proposed. Three types of engineering slopes are studied to discuss the impact of two typical earthquake ground motions on seismic permanent displacement. The results show that: this method is compatible with the previous method without considering the vertical acceleration; the combined effect of horizontal and vertical accelerations is different for various earthquake records, and the influence of vertical acceleration on the permanent slope displacement cannot be ignored.