| Honghe is located in the south of Yunnan Province,is high geo-hazards susceptibility area in Yunnan Province.The county town of Honghe is the center of economic and cultural of Honghe,mostly located at the top of Yisha ridge between the Honghe Rvier basin and the Menglonghe Rvier basin.The area had complex geological structure,intense neotectonic movement,greatly undulate terrain,developed gulches,steep bank slopes,Intense cutting and retrogressive erosion,widely distributed soft rock,strong human engineering activities,developed geological disaster at the moment,which constituted the complex geological environment of study area.In recent years,in order to break the situation of "Urban development" and "Geological disaster",carried out a series of comprehensive management of geological disasters at the county town of Honghe,which achieved remarkable results.However,the impact of human activities on the geological environment is strong,geological disaster is still grim,so timely development the risk assessment of study area,can provide scientific basis for urban planning,disaster prevention and mitigation.Based on the detailed investigation and Research on the development of geological hazards in Honghe County,taken the geological hazard factors,constructed the risk assessment model for geo-hazards,used Arcgis' s powerful spatial analysis and data processing functions,carried out the the risk assessment of geol-hazards in the study area.The main results are as followed:(1)The county town of Honghe has developed geo-hazards,mainly with landslide and debris flow,intensive developed at the top of Yisha ridge and the southern slope belt,but the collapse was weak developed.The area of weak rock which consist of semi-binder breccia and conglomerate widely distributed,with slope section from 40 to 60,with strong human engineering activities,and the high steep slope zone of debris flow gully and gully,were the high landslide susceptibility area.(2)Taken Analytic hierarchy process,combined with geological environment.Established the geol-hazards assessment model and index system of geo-hazards.Selected four influence factor of slope,elevation,engineering geological rock group and intensity of human engineering activity,combined with the Arcgis software,completed the geol-hazards assessment before the treatment.The geo-hazards before the treatment is mainly small-scale,and Among them large,relatively large,medium,small,very small area accounted for 2.9%,4.6%,15.5%,46.0%,31%.(3)Used qualitative and quantitative methods to establish the evaluation system of geol-hazards treatment.Slected three indexs of standardization of project implementation,effectiveness of control the geo-hazards,benefit of the control engineering to complete the effect evaluation of treatment engineering.taken the control effect as a reduction factor to multiple the index of geo-hazards before the treatment,geted the geo-hazards after treatment.The grades of geo-hazards after the treatment is mainly very small-scale.and Among them large,relatively large,medium,small,very small area accounted for 0.16%,1.76%,5.79%,23.59% and 58.7%.Indicated the effect evaluation of treatment engineering is Significant,the risk index decreased significantly,but the geo-hazards still existed.(4)Taken the indexs of population density and land cover to complete vulnerability assessment of geo-hazards.The results show that the vulnerability of geo-hazards is medium-scale.Among them large,relatively large,medium,small area accounted for 6.39%,20.85%,53.2%,19.56%.(5)Taken the product of the idex of geo-hazards after treatment and vulnerability of geo-hazards as the conclusion idex of risk assessment of geol-hazards.The results show that the risk of geo-hazards is very small-scale.Among the grades large,relatively large,medium,small area accounted for 0.58%,5.94%,15.47%,28.26%,49.75%.The areas which the risk of geol-hazards are large and relatively large are mainly distributed in platform margin of county town of Honghe where have Strong human engineering activities and source of channel where have strong erosion tracing and steep slope area of county center,the monitor and treatment of geo-hazards should be strengthen. |
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