Optimizing a prediction model for engineering disturbance hazard susceptibility along the China-Nepal highway in the Qinghai-Tibet plateau

The China-Nepal transportation corridor, a vital link, includes the western route of the China-Nepal Highway from Lhasa to the Jilong Border. This route has faced persistent engineering disturbance hazards since its construction in 1965, significantly compromising its safety. The planned China-Nepal Railway is set to be built largely in parallel to the existing highway. Therefore, a systematic study of the existing types, characteristics, triggering factors, and susceptibility zones of engineering disturbance hazards along the China-Nepal Highway can provide valuable insights for mitigating such hazards in future railway construction. Field investigation along the highway have cataloged over 160 hazard sites, classified into six main types: earth slides (14 cases), debris-bedrock binary slides (20 cases), earth-rock mixture slides (37 cases), earth-rock mixture falls (31 cases), rock falls (46 cases), and rock topples (13 cases). The susceptibility prediction model has been refined by applying the First Law of Geography to the hazards identified in field investigations. A comparison with ANN and Simple CNN models demonstrates that the proposed sample optimization strategy effectively enhances model performance. This strategy addresses the limitation in susceptibility prediction where point-format hazards fail to adequately represent the environmental characteristics of the entire hazard body. Results indicate two areas of extremely high susceptibility to engineering disturbance hazards along the China-Nepal Highway. The first area features rocky slopes with unloading fractures in broad river valleys, particularly where slate is exposed. The second area includes slopes of Quaternary loose deposits that have been disturbed by slope excavation in alpine valleys with heavy rainfall.