Loess Geological Disaster Risk Assessment And The Comprehensive Countermeasure

ShannXi province plays a strategic role in West Development, especially with the fast construction of the energy source and chemical industry foundation, the northern region of ShaanXi province becomes the emphases of the strengthening the dominant industry and cultivating the economical increase. But the ecological environment of the loess area is quite vulnerable, the land is crisscrossed by ditches and streams, geological hazards struck the area frequently, which result in great losses of man's life and property and the society. Thus, investigating the geological hazards and strengthening the research on evaluating the risk of the geological hazard, as well as the compositive countermeasures play an important role in decreasing loss,quickening economical development and realizing the sustainable development of society , economic and environment.Based on studying of the geological and geographical environment, including nature geographical conditions, geology geomorphic features, hydrological conditions, loess stratum structure features and so on, at the northern region of ShaanXi province. Firstly, the author studies the features and the development characteristics of major geological hazards, such as landslip, landslide ,debris flow, surface subsidence and ground fissures; Secondly, the risk of the geological hazard evaluation system and the evaluation model were established which was based on the 18 first level factors including the scale, density, frequencies of historical hazard, the engineering geological conditions of the soil, the gradient of the landform, the number of the hazardous whether days each year, the ratio of the vegetation cover, the activity of economical engineering, the density of the population, the density of the villages and town, the rate of population aged from 20~40,the rate of population accepted high school education, the density of the buildings, the distributing of important energy source base, the density of main line communication, the importance of using land, the dependence among the first, second and the third industry, the dependence of the economical development to the outside, the 5 second level factors including the intensity of historical hazard, the form of hazard environment, the degree of society destroy facility , the degree of substance destroy facility ,the degree of economy destroy facility ,the 2 third level factors including the fatalness of the geological hazard and the destroy facility degree of objects threatened by hazard, the risk of the geological hazard in northern region was evaluated by using the multiple fuzzy compositive assessment method; Finally, the countermeasures to the geological hazard were promoted from three aspects: controlling and governing, engineering treatment, biological protection and treatment.