Regional Rainfall Landslide Hazard Assessment Based On SCOOPS3D And TRIGRS Models

Rainfall is one of the main factors that induce landslides.The quantitative evaluation of regional rainfall landslide risk with different models is one of the hot topics in the study of landslide geological hazards at home and abroad.TRIGRS is one of the most widely used models for evaluating the risk of shallow rainfall landslide at home and abroad,SCOOPS3D model is one of the latest models for quantitatively evaluating the risk of large deep landslides.Wudu district of south Gansu province is one of the most intensive areas of landslide development in Gansu province and even the China.In this paper Dujiagou drainage area of accumulation layer landslide in Wudu district and Haojiagou drainage area where loess landslide is most developed are taken as the research area.SCOOPS3D and TRIGRS models are adopted to conduct quantitative evaluation of rainfall landslides in the two drainage areas.The research results are as follows:(1)When the maximum single-day rainfall in Dujiagou basin exceeds 59.2mm once every 10 years,67.6mm once every 20 years,78mm once every 50 years and 82.2mm once every 100 years,the landslide area of shallow accumulation layer increases respectively by 0.047km~2,0.11km~2,0.23km~2,0.26km~2,the landslide area of deep accumulation layer increased respectively by 0.14km~2,0.18km~2,0.28km~2,0.42km~2.(2)When the maximum single-day rainfall in Haojiagou basin exceeds 68.85mm once every 10 years,80.1mm once every 20 years,93.6mm once every 50 years and 103.95mm once every 100 years,the landslide area of shallow accumulation layer increases respectively by0.114km~2,0.175km~2,0.25km~2,0.275km~2,the landslide area of deep accumulation layer increased respectively by 0.076km~2,0.08km~2,0.15km~2,0.16km~2.(3)Under the same conditions,the percentage of high-danger area of shallow landslide in Haojiagou basin is higher than that in Dujiagou basin,and the percentage of high-danger area of deep landslide in Dujiagou basin is higher than that in Haojiagou basin.The reason for the difference is that the Dujiagou basin is loess,the loess surface is sensitive to rainfall,and easily occur many shallow small landslides.The accumulation layer in Dujiagou basin is the residual sediments of phyllite with high permeability..After long-term rainfall infiltration,the physical parameters of soil are reduced,resulting in the increase of underground water level above the sliding surface of the accumulation layer landslide and the increase of pore water pressure.Therefore,deep landslides often occur.