Hazard evaluation of the slope in Shenzhen based on airborne LiDAR data

Objectives: With the development of Shenzhen, land renovation is frequent. At the same time, affected by the subtropical monsoon climate, the area under the jurisdiction has abundant rainfall and dense vegetation coverage, making it difficult to identify the hidden dangers of geological hazards widely distributed on artificial slopes and natural slopes. Therefore, it is necessary to develop a set of hazard evaluation system of geological disaster that can solve the unique terrain and climate conditions in Shenzhen, so as to achieve the purpose of preventing disasters in advance and reducing casualties. Methods: (1) we use the high-precision DEM of Shenzhen city obtained by airborne LiDAR as the data source, and Obtained about 3500 slope disaster prone points in Shenzhen through data collection, remote sensing interpretation, and field verification. The sample library expanded to 330% after proofreading;(2) Comprehensive consideration of three major factors (8 factors) of terrain, geological structure and human engineering activities, and based on the rainfall-induced disaster mechanism, a rainfall collection factor RCF (Rainfall collection factor) is proposed, and the weight of evidence method is used to complete the geological disaster hazard evaluation under rainfall-induced conditions.;(3) The threshold determination method of "key point control" under the actual background of single disaster is proposed, and the classification of the risk assessment model is completed. Results: The AUC value of ROC model test reached 0.903, indicating that the model has a good effect on disaster forecasting. LiDAR technology can improve the identification accuracy of geological hazards in cities under dense vegetation coverage. Conclusions: Based on airborne LiDAR data, through a series of means such as expansion of disaster database, analysis of disaster distribution law, establishment of disaster evaluation factors, and classification of risk levels, it can form a refined evaluation system for the hazard evaluation of the slope in densely vegetated areas under the influence of the subtropical monsoon climate in the southeast.