EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Spatiotemporal characteristics of discontinuous slope failures

Yong Li
Yong Li
  • Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, 610041, China

Slope failures are important material supplies for debris flows, and field observations have indicated that failures are random and discontinuous. However, few studies focus on the nature of failures in succession. This study reports groups of field experiments of soil failures under artificial rainfall on slopes in two debris flow valleys, the Jiangjia Gully (JJG) in Yunnan Province, and the Niujuan Gully (NJG) in Sichuan Province, in southwest China (Fig.1).

Fig.1 Experimental sites of the study (upper, NJG; lower, JJG)

It is found that failures occur separately and intermittently on slopes; a slope process is composed of a failure sequence (Fig.2), which presents similar properties under different rainfalls and slope conditions: 1) the sequence is primarily random, with weak autocorrelation and small correlation to time progress and less dependence on rainfall; 2) the time interval between failures satisfies the exponential distribution, and the average interval decreasing with rainfall intensity, implying the frequency increases with rainfall intensity; 3) the magnitude of failure fluctuates up to three orders, from several to hundreds of volume unit (10-3m3); and the distribution follows the power law, with total amount increasing with rainfall intensity.