Abstract: Extensively developed in the high and cold mountainous areas in west China, granular soil slopes give rise to disaster chains accompanied with collapses and debris flows. The scale of such disaster chain is closely related with the debris yield rate of granular soil slope. With the Sino-Pakistan highway and the Tianshan highway as case study, we investigated the debris yield rate by comparing the point-cloud data in different time periods via 3D laser scanning approach, and further built a monitoring and results of early-warning model to obtain the cleaning time intervals and the criteria of early-warning levels. By comparing the predicted early-warning levels of five granular soil slopes, we found that the predicted results are in general consistent with in situ survey results. The research findings can be taken as reference for estimating the cleaning time duration and the design of prevention and control of granular soil slopes.

Key words: granular soil slope, debris yield rate, three-dimensional laser scanning, early warning and monitoring model, time intervals of cleaning