Developments of phenomenological approach on dynamic landslides movemnts

以2011年日本东北大地震时发生在加宽填土中的绿丘4号滑坡为例，计划并实施了地震时滑坡动态运动的现场观测。最大的倾斜地震反应被发现在软弱层，在顶部的土壤的基础上的填料和脆弱的褐煤层的岩石。这些结果表明，在地面结构的薄弱层自卸。自倾效应随软弱层厚度和地震周期特征的不同而不同。超静孔隙水压力与水平峰值速度的关系表明，滑坡是在强震作用下滑带土抗剪强度完全丧失而引发的。滑坡在强震动作用下的表现，还没有根据观测事实进行讨论。对地震过程中滑坡运动进行精确的现场观测，对减轻城市地区滑坡灾害具有重要意义。

Field observations of landslide dynamic movements during earthquakes were planed and conducted in the landslides, the Midorigaoka #4 landslide, occurred in the widening fills by 2011 Tohoku earthquake. The largest seismic response of inclination was found at the weak layers, at the top soils of the base of fills and at the fragile lignite layer of bedrocks. These results indicate the self-dumping at the weak layers in ground structure. The effects of self-dumping varied depend on the thickness of weak layers and period characteristics of earthquakes. The relation between excess pore water pressure and horizontal peak ground velocity suggests that the landslide was initiated by the fully loss of shear strength of slip layer during the strong seismic motion. The performance of landslide during strong motion has not been discussed based on observed facts. Precise field observation on landslide movement during earthquake should be significant to mitigate the landslide risk in urban region.