地震边坡超低摩擦效应启滑机理分析

Analysis of Open-slip with Anomalously Low Friction Effect of Slope under Earthquake

为研究地震作用下含结构面边坡的超低摩擦效应及启滑机制,将含单一结构面边坡简化为等效质量-粘弹性模型,采用理论分析与数值模拟相结合,以结构面法向应力状态及滑体与基岩的相对法向速度和位移为研究对象,得到了地震作用下基岩-滑体相对法向速度和位移以及结构面法向应力变化规律,揭示了含单一结构面边坡系统超低摩擦效应的实质。结果表明:地震载荷的波动造成滑体与基岩法向相对位移正负交替,结构面法向动应力正负变换,当结构面法向动应力为负时,系统出现超低摩擦效应,坡体发生累进性变形破坏。

In order to investigate the anomalously low friction effect and the mechanism of opening slide of slope with structural plane under earthquake,the slope with single structural plane was simplified to equivalent mass-viscoelasticity model.Combined theoretical analysis with numerical simulation,the normal stress state of structure plane and the relative normal velocity and normal displacement of fundamental rock and landslide was taken as a research object,the evolution law of normal stress state of structural plane and the relative normal velocity and displacement between fundamental rock and landslide under seismic load were obtained.The essence of anomalously low friction effect in the system of slope including single structural plane was revealed.The results of theoretical analysis and numerical simulation show that the fluctuation of the seismic load leads to the negative and positive alternating of relative normal displacement between fundamental rock and landslide,the increase and decrease of normal dynamic stress occur alternately,when the normal dynamic stress is positive and the anomalous low friction phenomenon occurs in the dynamic system,and the slope will deform with progressive failure.