Abstract:At about 11:00 a.m. on July 10, 2024, a shallow soil landslide triggered by heavy rainfall occurred in Sanxingdian Village, Shazhenxi Town, Zigui County, Yichang City, Hubei Province. The landslide volume was approximately 30×10? m3. Thanks to the timely detection by community-based monitoring and prevention staff, 206 individuals from 74 households were successfully evacuated. To investigate the formation process and disaster-inducing mechanism of Zhangjiahongwuchang Landslide, this study explored its dynamic processes and genesis mechanisms through field surveys, borehole data analysis, rainfall data, and numerical simulations. The results of field surveys and borehole data analysis showed that the landslide material consisted of Quaternary gravelly soil with a soil-torock ratio of 6: 4. The sliding surface was characterized by a "smooth" bedrock-overburden interface, and the catchment area at the rear edge of the slope was 27 545 m2. Numerical simulation results demonstrated that 16 hours of cumulative rainfall from July 3rd to July 4th led to a significant decrease in landslide stability, and the heavy rainfall on July 9th directly triggered landslide failure. Preliminary research suggested that the landslide was located on a unilateral slope on the western flank of the Zigui Syncline. Loose Quaternary gravelly soil and a "smooth" bedrock-overburden interface were internal factors triggering this landslide. External factors included cumulative rainfall of 212 mm from July 3rd to July 4th and heavy rainfall of 170 mm on July 9th, surface runoff from rainfall on the extensive slope outside the landslide that converged into the landslide mass, and abandoned drainage systems on the slope surface of the landslide mass.
