Sensitivity Analysis Of Grid Size To Risk Index In Geological Assessment Factors

Geological disasters,as a kind of disasters,in recent years,its frequent occurrence not only caused great harm to the stability and development of society,but also have a great threat to the natural environment and human life safety.More and more experts and scholars have conducted more in-depth research in geological disaster prevention and risk assessment.In the process of geological disaster risk assessment in the study area,how to carry out geological disaster risk assessment in the study area based on the geological hazards in the study area and its specific natural geological conditions,how to assess the geological hazard risk of the study area based on the geological disaster hazards in the study area and its specific natural geological conditions,and how to determine the influence of the grid size on the risk sensitivity of risk factors of geological disaster risk assessment in the evaluation process,has very important research value and practical significance.This paper summarizes and elaborates the research status and progress of the related evaluation methods and model division methods by studying the literatures of a large number of geological hazard risk assessments at home and abroad.Based on this,taking the Linfen City of Shanxi Province as an example,a systematic survey and analysis of the geological disasters that occurred in the city’s history was conducted.The geological hazard points,annual precipitation,landform type,geotechnical engineering,and terrain slope,ground motion peak acceleration were selected as evaluation factors,in the process of geological disaster risk assessment,the size of the grid to assess the sensitivity of factor risk index was analyzed.Thesis mainly includes the following contents:(1)For the uncertainty in the research process of the collapse landslide and debris flow,it applies the deterministic coefficient method to calculate the CF value corresponding to each evaluation factor sub-layer.By adding,deleting,modifying,topology,and corresponding spatial analysis of the attribute table of the original data,the ultimate evaluation factor thematic layer and hidden danger layer will be obtained,the related parameter values will be statistically calculated according to the formula,and the evaluation factor sublayer will be finally obtained through calculation CF_i.(2)Different sizes of regular grids were divided in the study area(the grid scales were 200m,300m,400m,500m,and 600m,respectively),and the sensitivities of the grids to the risk factors of each evaluation factor were analyzed..Firstly,each evaluation factor is compared with grids with different scales,and then the grid is assigned according to the percentage of area,that is the grid is uniformly processed.According to the corresponding weights of the evaluation factors given in the paper,the weighted average calculation of the grid makes a grid finally correspond to a unique risk index value(F value)under different grid scales.SPSS is used to count each grid scale.The distribution characteristics of the lower F-values are analyzed.Connect the F-value calculated in each grid scale with the corresponding grid point layer,and based on this value,Kriging interpolation of the grid point layer is used to plot the geological hazard zoning map of Linfen collapse-slip flow at different scales.Taking the 1:50 million Linfen City collapse-risk flow hazard map as a benchmark,the hazard area map on a single grid scale is compared with the reference map and other results on the scale.The analysis showed that the sensitivity index of the risk factor of the evaluation factor was weak under the three grid scales of 300m,400m and 500m.(3)Counting and analyzing the area error of the vector planar layer evaluation factors under different grid scales,the results are that the I,IV type of geotechnical engineering and I and II types of slope are available at the three grid scales of 300m,400m,and 500m,the I and II types of slope has a significant increase or decrease trend.This result is consistent with the result described in step(2).That is,under the three grid scales,the risk index of the geological hazard assessment factor risk index is the least.