The Kangjiapo landslide in Wanzhou district, Chongqing city: reactivation of a deep-seated colluvial landslide in the Three Gorges Reservoir

Abstract How to reduce landslide risk economically and effectively is a very meaningful and challenging research topic. In particular, it is difficult and expensive to completely control deep-seated colluvial landslides. Taking the Kangjiapo landslide in Wanzhou district, Chongqing city, China as a case, this study focuses on measures to prevent and control the risks of deep-seated colluvial landslides through detailed investigation and monitoring. The Kangjiapo landslide is located in the Three Gorges Reservoir area, and it is part of a famous ancient landslide named the Pipaping landslide. The steep sliding surface in the rear was not found during the first treatment, the Kangjiapo landslide has been reactivated since 2015. Field investigations, monitoring, borehole and related test were conduct to identify the landslide characteristics and mechanisms. The landslide deformation was not spatially or temporally uniform according to monitoring data analysis. The landslide is less likely to fail in general because the sliding surface in the front is very gentle. The reasons for Kangjiapo landslide reactivation could include the decline of the reservoir water level, a steep sliding surface in the rear, the existence of a sliding zone with low strength due to a long period of reservoir immersion. Landslide risk mitigation measures are proposed for the deep-seated landslide, including stabilizing piles nearby the road, and a BeiDou Navigation Satellite System and MEMS inclinometers in the platform.