Rain-triggered landslide hazards and mitigation measures in Thailand: From research to practice

Recently, the frequency of rain-triggered landslides in Thailand has been on the increase and has gained momentum, coincident with the effects of climate change. In this regards, the impact of landslide on roads and highways in the hilly and mountainous terrains has also increased. Non-structural landslide mitigation measures, including early warning and hazard mapping, as well as structural mitigation measures with the application of geosynthetics, have been exploited in localities where rain-triggered landslides are a potential threat to human life and property. For early warning, the use of critical Antecedent Precipitation Index (API) is proposed to be most appropriate. Furthermore, deterministic hazard mapping technique incorporating the modern day geospatial technologies can also provide a useful platform to analyze a number of scenarios including rainfall and land cover/land use variations. Finally, a parametric study on a designed and constructed reinforced soil slope with polyester polymer geogrids revealed that the stiffness of backfill is very sensitive to moisture contents or wetting due to rainfall which can influence the performance of reinforced slope structure.