| The Southern of Gansu province,where was widely distributed thick loess,and the Loess vertical joints and fissures are developing wide-spreadly.In this area,the new tectonic activity is active,the earthquakes are active and strong,the rainfall is concentrated and heavy,with all these objective factors,making the natural geological conditions in the region extremely fragile and is a geological hazard prone area of China.Luoyugou Basin,which lies in the northern suburbs of Tianshui,is just located in the interactive zone of hilly and gully region on Longxi Loess Plateau and the Longnan Mountain,and its climate,geomorphology and landslide development provide with particularity and representative on the Loess Plateau of Longxi.The simulation research on the loess shallow landslide susceptibility distribution pattern for the basin,which helpful in understanding the dynamic process and physical mechanism of loess shallow landslides and providing technical support for the loess shallow landslide monitoring,early warning and prevention in the future,meanwhile,it can provide scientific basis to the local government for rationally using and planning the land.Therefore,taken the Luoyugou Basin as the study area,basedon the GIS platform,this research adopts CRESLIDE model to simulate the landslide stability of Luoyugou basin,and explores the impact of hydrological processes on the stability of the loess shallow landslide.Further,the paper realizes loess shallow landslide susceptibility zoning mapping through the zoning classification towards potential prone area,hoping to provide valuable reference for the local land-use planning so that the landslide disaster losses can be reduced to minimum.The main conclusions are as follows:1、By the means of adaptive random search method(ARS)(automatic cycle)to adjust the global parameters of the CRESLIDE model,the optimal parameter set is obtained.Based on the optimal parameter set,the CRESLIDE model is used to simulate the hydrological process of the study area until the simulated flow curve and the actual observed flow curve trend provide good consistency,which prove the CRESLIDE model is suitable for the study area for hydrological process analysis.2、By comparing the stable zone results achieved by the CRESLIDE model and the SBAS-InSAR technology,it can be found that most unstable regions are located on slope,and the spatial distribution patterns results are also consistent for both methods,which can explain that the CRESLIDE model is suitable for loess shallow landslide stability study in the study area.3、Based on the CRESLIDE model,the spatial data of the rainfall-surface runoff-landslide stability spatial distribution is constructed,and the temporal and spatial evolution pattern of rainfall-runoff-slope stability is studied.When continuous rainfall occurs,the amount of infiltration will increase,slope stability will be reduced,except for the vegetation cover-better area4、Based on the CRESLIDE model(the rainstorm survey data obtained from Tianshui Hydrology Bureau),the stability coefficient of the whole landslide decreases along with the increase of daily rainfall.When the daily rainfall reaches 94.43 mm,the increasing rate reduced,that the stability coefficient of the landslide decreases with the increase of the daily rainfall,is slower.5、By developing the loess shallow landslide susceptibility zoning simulation using the CRESLIDE model,it can be discovered that the extremely high prone area and high prone area accounts for more than 50% of the whole area,followed by low prone area and lower prone area,and the least is medium prone area.Further,the extremely high prone area and high prone area lie mostly on the right bank,since loess cover is thicker in the right bank,the vegetation cover on the right bank is not good as the left and the farmland land accounts for the majority,when the rain occurs,rainwater infiltrates into the soil,change the soil water content,weaken the soil shear strength,which easy to cause landslide instability. |
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