FORMATION MECHANISM, DEPOSITS AND MOTION CHARACTERISTICS OF THE TYPICAL LOESS LANDSLIDE IN SOUTH JINGYANG PLATFORM

Loess landslides occurred frequently due to continued diversion irrigation in South Jingyang Platform, Shanxi Province. A loess landslide occurred near Miaodian Village on May 26, 2015, which destroyed several acres of farmland. In this paper, we regarded "5.26" landslide as a typical case study. Through detailed field investigation, mapping, investigation and so on, analysing its triggering factors, motion and accumulation characteristics. The results showed that:(1)The sliding distance was 278 m, the width of scarp is 222 m with a difference of 40 m in elevation, and the main sliding direction is 45°. (2)The landslide belongs to the phased landslide, which had been sliding for four times. The area of deposits is about 6.2×10⁴ m² and the total volume is about 50×10⁴ m³. The average deposit thickness is about 10 m. (3)The main triggering factor of the landslide is continued irrigation, but the surface visible cracks and deep cracks plays an important role in the advantage infiltration, which leads to the continuous uplift of the groundwater level. And the width and sliding direction of the landslide are controlled by the joints of the edge scarp. Finally, based on the certain relevance between the frequency of the landslide and rainfall, the influence of rainfall on the landslide event and the possibility of landslide recurrence are discussed.