Mechanism of the November 2018 landslide at the Kunming landfill and the geotechnical engineering risk control in the process of urbanization

This article presents the findings of a landslide that occurred on 18 November 2018 at the Huadili landfill site in Kunming, Yunnan Province, China, which caused the burial and destruction of nine houses and blocked roads along the route. The volume of the landslide sliding was approximately 9.1 × 105m3 and the maximum sliding distance of the leading edge was 180 m. The investigation of this disaster, which combined information gathered on landfill operations and multi-period satellite imagery, reveal the increase in the volume of soil discarded from the landfill and the changes in the disposal site over the last four years before the landslide occurred. As a result of altered hydrogeological conditions, the mechanical strength of the waste soil deposition decreases under the effect of long-term rainfall infiltration and softening by leaching, eventually inducing landslides. The basic characteristics and information on landslide deformation and movement, as well as the physical and mechanical parameters of the landslide mass and slip zone, were obtained through site investigation, borehole survey and indoor direct shear tests. To improve the accuracy of landslide risk assessment for similar types of potential disposal sites, we simulated the kinematic and kinetic processes of the Huadili landslide using a friction model in the numerical software DAN-W. Finally, how to better manage the geotechnical risks associated with urbanisation is discussed from the perspective of landslide genesis and triggering mechanisms.