Investigation of dynamic response and deformation characteristics of loess landslide under near and far earthquakes: A case study of Liping landslide in Tianshui earthquake area, Gansu Province

Seismic landslides in the loess plateau of China have severe disastrous effects and high potential risks.The response and deformation mechanism of seismic landslides is one of the hot topics of research.Taking the large-scale loess landslide in Liping Village in the Tianshui earthquake area as an example, the authors used the standard sine wave to explore the characteristics of the dynamic response influence on the landslide from local and remote earthquake ground motion elements, and inverted the actual Wenchuan remote earthquake and the local earthquake in Minxian County.According to the results obtained, the variation of PGA amplification factor at the measuring point with amplitude is related to the position of monitoring point:when the height of monitoring point is greater than 0.75 times overall height of the slope, the PGA amplification factor of monitoring point basically decreases with the increase of amplitude; when the height of monitoring point is less than 0.75 times overall height of the slope, the PGA amplification factor of monitoring point increases significantly with the increase of amplitude; the PGA amplification factor at the measuring point is negatively correlated with the frequency.Slope deformation is positively correlated with amplitude and duration:when the amplitude and duration increase, the maximum horizontal and vertical displacement of monitoring points shows an increasing trend, the critical amplitude of the slope body's sharp deformation is about 0.05 g; when slope deformation is negatively correlated with frequency, the frequency increases, the maximum horizontal and vertical displacement of monitoring points decreases, the critical frequency of rapid deformation is about 5 Hz; the impact of amplitude on slope instability is greater than that of frequency on slope instability.Compared with the local earthquake in Minxian, the movement of main sliding body is inseparable from the high amplitude, low frequency, and long-lasting seismic waves generated by the Wenchuan earthquake.If the strong far earthquakes is ignored in the study of earthquake landslide stability Impact, significant safety risks may occur.In this paper, the research method about dynamic response and deformation difference of landslides caused by near and far earthquakes has certain reference significance for the research on earthquake landslide stability.