Factors Controlling Kinematic Behaviour of a Huge Slow-Moving Landslide in China

Abstract

Xieliupo landslide, located in the Zhouqu County of northwest China and with volume of 72 × 10⁶ m³, is a slow-moving landslide for more than 100 years. Several violent slide events have been recorded during its active history. However there has been an argument among professionals about mechanism of the landslide, particularly factors controlling its kinematic behaviour. A detailed investigation found that kinematic behaviour of the landslide may be affected by either an active fault with strike displacement rate of 1.4 mm/a, or river incision at its toe or a combination of those above, apart from its gravity and soft nature of its materials. To understand roles of these factors in slow-moving behaviour of the landslide, a numerical modelling was carried out. Results of the modelling show that gravity of the landslide and visco-plastic nature of its materials may play predominant roles in activity of the landslide followed by the active fault and river incision. The active fault accelerates the landslide velocity by 20–30 %, whereas the lateral incision by the river water may just locally intensify activity of the landslide, mainly in the zone behind the river bank 50–70 m.