Evaluation Of Geological Hazards Under Territory Development Plan System In Lanzhou City

Territorial development plan is a guide for national spatial development and a spatial blueprint for sustainable development.It is the basic basis for all kinds of development,protection and construction activities.It is also a major deployment made by the Party Central Committee and the State Council.Territory development plan is based on the evaluation of resource and environment carrying capacity and suitability of territory development(short name: dual-evaluation),disaster evaluation under dualevaluation is one of the important components,completion of the evaluation of geological hazards in the function of urban construction can support the improvement of dual-evaluation,it also can provide scientific basis for the compilation of territory development plan.Based on a lot of work done by the predecessors,this paper collects relevant data and evaluation of geological hazards in Lanzhou City by AHP,and has drawn the following conclusions:(1)Lanzhou City is located in the northwest of the Longxi Loess Plateau,with complex geological conditions,a total of 2470 potential geological hazards were developed in the city,including 335 landslides,205 collapses,1661 unstable slopes,257 debris flows,and 12 ground collapses.(2)This paper has classified statistics on geological hazards in Lanzhou,the characteristics of geological hazards in Lanzhou are as follows: Geological hazards in the city are very widespread and extremely unevenly distributed.Under the influence of heavy rainfall,irrational irrigation,and human engineering activities,the geological disasters in the area show the characteristics of repeated activities to varying degrees.At the same time,it exhibits typical sudden and mass characteristics.(3)Based on field investigations and previous studies,this paper constructs an evaluation system for the susceptibility to geological disasters in Lanzhou city.This paper selects these 14 evaluation factors as the evaluation index of susceptibility and quantify them: vulnerability to geological hazards,hazard point density,terrain slopes,cutting depth,gully density,geomorphic type,rock soil mass types,geological structure,vegetation coverage,1-h precipitation,3-h precipitation,24-h precipitation,seismic intensity,human engineering activities.Then,establish an evaluation model by using AHP weighted superposition,Finally,this paper divides the study area into four levels of low-prone,medium-prone,high-prone and very high-prone.(4)According to the safe distance of the active fault and the peak acceleration of the ground motion in Lanzhou,this paper completed seismic risk evaluation in Lanzhou city.Combined with the evaluation results of the susceptibility to geological hazards in the city,this paper completed the hazards evaluation of urban construction in Lanzhou city.In the end,this paper divided the research area into four grades: medium danger zone,higher danger zone,high danger zone,and very high danger zone.