ON APPLICATION OF SOIL-WATER CHARACTERISTIC CURVES TO LANDSLIDE FORECAST
LIN Hungchou1，2，YU Yuzhen3，LI Guangxin3，PENG Jianbing1
(1. Key Laboratory of Western Geological Resources and Geological Engineering of Ministry of Education，Chang¢an University，Xi¢an，Shaanxi 710054，China；2. State Key Laboratory of Geohazard Prevention and Geoenvironment Protection，Chengdu University of Technology，Chengdu，Sichuan 610059，China；3. State Key Laboratory of Hydroscience and Engineering， Tsinghua University，Beijing 100084，China)
Abstract：The determination and application of soil-water characteristic curves(SWCCs) are key issures for unsaturated soil mechanics in geotechnical engineering practice. Unfortunately，it is hard to use in practice owing to the complexity of SWCCs. Hence，the landslide model tests for soil slope under artificial rainfall and numerical analyses are used to study the practicability of main drying and wetting curves in SWCCs. In the numerical analyses，the pore water pressure in slopes is calculated by the finite element analysis of water flow through unsaturated-saturated soils；and the slope stability is evaluated by finite element method in consideration of shear strength reduction technique. The results show that the actual occurrence time of landslide is between the evaluated time of main drying curve and main wetting curve in general condition；and the occurrence time of landslide which is evaluated by main drying curve is shorter than main wetting curve. It is implied that the main drying curve and main wetting curve can be used to build rainfall warning criteria for rainfall-induced landslide hazards. Consequently，the main drying and wetting curves of SWCCs are the most significant simplified hysteresis model for unsaturated soil slope seepage numerical analysis. Because the main drying and wetting curves represent the two boundaries of soil state path；it is appropriate for using these two boundary curves to build up rainfall warning criteria of landslide hazards for specific mitigation purpose such as emergency response.
