A possible mechanism of earthquake-induced landslides focusing on pulse-like ground motions
A possible mechanism of earthquake-induced landslides focusing on pulse-like ground motions
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DOI：
10.1007/s10346-020-01597-y
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发表时间：
2021-01
期刊：
影响因子：
6.7
通讯作者：
Guang-qi Chen;Ming-yao Xia;D. T. Thuy;Ying-bin Zhang
中科院分区：
文献类型：
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作者：
Guang-qi Chen;Ming-yao Xia;D. T. Thuy;Ying-bin Zhang
本文基于非连续变形分析（DDA）方法，提出了脉动型地震动（PLGM）诱发地震滑坡的机理。在最近的近断层地震诱发的滑坡中，有两种现象使滑坡研究人员感到困惑。一是PGA小的地区发生大规模滑坡，而PGA大的地区没有滑坡，如2016年熊本地震时发生的滑坡。另一种是一侧边坡坍塌，而另一侧边坡背靠背保持稳定。例如，在2018年北海道地震中，大多数西侧斜坡坍塌，而东侧斜坡背靠背保持稳定。为了用PLGM解释近断层地震诱发滑坡的两种现象，采用DDA方法对两种地震中不同地震动作用下的对称边坡模型进行了分析和讨论。分析结果表明，PLGM可能是近断裂带同震滑坡的主要触发因素，而PGA可能不是地震诱发滑坡的正确参数。同时，边坡的崩塌方向与PLGM的速度脉冲和边坡的强度参数都有关系。本文提出的PLGM近断裂带地震诱发滑坡的机制考虑了边坡的抗拉强度和抗剪强度，可以很好地解释2016年熊本地震和2018年北海道地震的滑坡起爆现象。结合两个地震实例，研究了PLGM与正向方向性效应的关系，更准确地阐明了近断裂带同震滑坡的起爆机制。
This paper proposes a mechanism of earthquake-induced landslides with pulse-like ground motion (PLGM) based on the discontinuous deformation analysis (DDA) method. In recent near-fault earthquake-induced landslides, the two phenomena confusing landslide researchers are observed. One is that large-scale landslides occurred in the area with small PGA but no landslide in the area with large PGA, for example, the landslides occurred during the 2016 Kumamoto earthquake. The other is that one side slopes collapsed while the opposite side slopes back to back remain stable. For example, most west-faced slopes collapsed while the east-faced slopes back to back remain stable in the 2018 Hokkaido earthquake. To explain the two phenomena in near-fault earthquake-induced landslides with PLGM, a symmetrical slope model subjected to different ground motions during these two earthquakes are analyzed and discussed by using the DDA method. The analysis results show that PLGM may be a major triggering factor for co-seismic landslides in the near-fault region, while PGA may not be the right parameter for the initiation of the earthquake-induced landslides. Meanwhile, the aspect of collapsed slope is related to both the velocity pulse of PLGM and strength parameters of the slope. The proposed mechanism for the earthquake-induced landslides in the near-fault region with PLGM considers both tensile and shear strengths of the slope, which can well explain the landslide initiation phenomena in the 2016 Kumamoto earthquake and the 2018 Hokkaido earthquake. The relationship between PLGM and forward directivity effect is also studied in combination with two earthquake cases to more accurately clarify the mechanism of the initiation of co-seismic landslides in the near-fault region.