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以野外实际调查资料为依据,总结分析甘肃陇西黄土高原滑坡类型及特征的基础上,从降水(主要指强降雨)改变地形地貌、改变滑坡土的成分构成、改变滑坡的土体结构、改变滑坡的力学强度4个方面阐述了大气降水对黄土滑坡形成的机理。大气降水对黄土滑坡的时空分布存在着较大影响和控制,年际上,同一区域滑坡发生的频次与多年降水的强弱过程呈现良好的相关性,存在丰水年滑坡次数多、规模大而枯水年滑坡次数少、规模小的规律;年内滑坡集中出现于3月份和6～9月份,前者是季节性冻结—融化作用所致,后者是降水在时间上的集中决定了滑坡发生时间的集中性;不同区域,在地形地貌、地层岩性基本相同和植被覆盖率相差不大的条件下,降水量越大,滑坡发生频率越高,反之,亦然。
Based on the actual field survey data, the types and features of landslides in Longxi Loess Plateau are summarized and analyzed. The topography of the landslides is changed by precipitation (mainly heavy rainfall), the composition of the landslide soil is changed, the soil structure of the landslide is changed, The mechanical strength of the four aspects elaborated the mechanism of atmospheric precipitation on the formation of loess landslides. Atmospheric precipitation has a great influence and control on the spatial and temporal distribution of loess landslides. In the interannual period, the occurrence frequency of landslides in the same area shows a good correlation with the intensity of many years of precipitation. There are many landslides with large scale In the dry years, there are few landslides with small scale and small landslides. Landslides occurred in March and June ~ September, the former was caused by seasonal freezing-thawing. The latter was caused by the concentration of precipitation in time, which determined the landslide occurrence time . In different regions, under the conditions of the same landform, lithology and similar vegetation coverage, the greater the precipitation, the higher the frequency of landslides, and vice versa.