坡脚型与偏转型地震滑坡运动距离及地形因素作用

运动距离作为滑坡防灾减灾的主要评价指标之一，不仅受到滑坡体积和落差的控制，还与滑坡的下垫面场地的地形作用相关。通过分析坡脚型和偏转型两类典型的地震滑坡运动特征，研究了滑坡体积V、落差 、坡度差 和偏转角度 对最大垂直运动距离H、水平运动距离L以及坡脚以下或偏转后的水平运动距离 的作用。由于偏转型滑坡受偏转前、后坡度和偏转角度对运动距离的共同影响，导致 指标小于坡脚型滑坡，而两类滑坡的 的均值较为一致，表明地形因素对不同类型滑坡的水平运动参数的作用具有一致性特征。分别建立了体积、落差与地形参数的坡脚型和偏转型滑坡运动距离拟合方程。拟合方程的参数指标表明：体积对H的作用指数较小，体现了高位滑坡的运动特征； 对 的影响指数较小；坡脚型滑坡的坡度 对运动距离的影响指数都较为显著，偏转角度 对偏转型滑坡的 的影响较为显著。研究结果为滑坡运动距离的预测和地形因素控制提供了参考，并且对于坡脚型和偏转型滑坡运动距离的模拟和机制研究而言，不应忽略坡脚坡度差和偏转角度的作用。

Influence of topographical factors on movement distances of toe-type and turning-type landslides triggered by earthquake

The movement distance of seismic-triggered landslide is one of the important assessment indexes for prevention and mitigation of landslides disaster, and it is not only controlled by landslide volume and drop, but also related to the topographical factor. Here the slope toe-type and turning-type landslides are analyzed and the influence of sliding volume V, drop , slope gradient and turning direction angle is studied on the maximum vertical movement distance H, transitional movement distance L, and transitional movement distance under the slope toe or after the turning . The results indicate that the apparent friction coefficient H/L of the turning-type landslide is jointly controlled by the gradient and turning direction, and less than that of slope toe-type landslide. The average value of of the toe-type landslide is equal to that of the turning landslide, showing that the influence of topography factor on the transitional movement distances of different types of landslides is similar. Analytical formulations for movement distances of the two types of landslide are developed with respect to the volume, drop and topographical factor of the slides. According to the formulations, it is found that the landslide volume affects trivially the maximum vertical movement distance H, showing the movement characteristics of the high slope-landslide; the drop is not the main factor influencing the horizontal distances under the slope toe or after the turning ; gradient significantly influences the movement distances , and of slope toe-type landslide; and turning direction angle is an important factor controlling the of turning-type landslide. These results can provide references for predicting landslide movement distance and controlling topographical factors, highlighting the importance of the slope gradient and the turning directional angle.