The Loess Landslide Hazard Analysis Of The South Bank Of Jinghe River In Jingyang District Using Copula Model

Due to the frequent occurrence of landslide geological hazard in Loess area in C hina, the assessment of landslide hazard has an important theoretical and practical significance in search for risk prediction, disasters prevention and mitigation. The current probabilistic landslide hazard analyses are performed under a hypothesis that the hazard evaluation elements are independent. However, these elements possess a definite relationship when delving into the landslide emergency. Therefore the traditional method of calculating hazard analysis by multiplying the hazard evaluation elements is no longer suitable for the research. Based on the previous studies, field investigation data and laboratory soil test, this thesis takes account of the case that the hazard factors have correlation, chooses the loess landslides of the south bank of Jinghe River in Jingyang District as the study object, evaluates the landslide hazard by using the method of half-qualitatively and half-quantitatively and Copula function model. The main research results are as follows:(1)A landslide hazard assessment system for the study area is proposed. Based on the theory and principle of the system, landslide distribution and developing characters, and geological environment conditions, Jiangliucun village to Fujiacun village region is chose to make the hazard zoning by dividing the line segment. Taking the mean posterior wall width as subsection length, 350 m is suitable for medium- scale landslide while 140 m for small scale. At last, confirm the effect scope by analyzing the investigation data.(2)Quantify and determine the hazard evaluation elements. Based on the field investigation data and empirical formula, the landslide magnitude(M) is calculated. According to the burst time of landslide and Poisson model, the frequency(T) is determined. And the slope stability factor is calculated by the GEO-SLOPE. Figure out the effects caused by the topography, hydrologic conditions, land-use and historical landslides events on susceptibility(S). Finally, use marking method to calculate the susceptibility.(3)Base on the landslide hazard model(traditional multiplication-based model), the correlation of landslide magnitude, frequency and susceptibility is analyzed. The results of the analysis M and S have significant correlation. Marginal distribution function of M and S is made and bivariate Cop ula function model is built as copulas of marginal distribution and joint distribution. Therefore, mathematical model of landslide hazard assessment is identified on the premise that hazard elements are correlated.(4)Considering the slope stability and landslide deformation data, the result of the prediction of landslide hazard, effects of human engineering activities, the potential sliding types, sliding distance and the influenced scope of landslide events, the hazard degree of landslide disaster in Jiangliucun village to Fujiacun village is divided to low hazard region, middle hazard region, high hazard region and extremely high hazard region, and hazard zoning map is made.