Research On The Relationship Between The Spatial Pattern Of Ancient Villages And The Risk Of Geological Hazards In Tangdan Town

The geological structure of the multi-disaster mountainous area is complex,and the topography and landform are quite different.It is a frequent occurrence area of geological disasters such as landslides and mudslides.However,under the influence of the disaster environment,many ancient villages have survived and their spatial layout has been continuously adjusted to adapt to the disaster environment.These remaining ancient villages are closely related to the local geographical and ecological environment and natural disasters in terms of spatial pattern.The study of the correlation between the spatial pattern of ancient villages in the mountainous region with multiple disasters and the risk of geological disasters is of great significance to the safety of rural construction in China,and also provides a scientific basis for the national revitalization of rural strategic development.Taking Tangdan Town ancient village in Dongchuan District as the research object,this paper explores the mechanism and mechanism of the impact of geographical environment and natural disasters on the spatial pattern of ancient villages by using grey theory,GIS technology,ENVI technology and fractal theory.Firstly,the risk assessment system of geological hazards is constructed based on GIS technology and grey relational method,and the hazard classification maps of Tangdan Town and the hazard classification maps of each index are obtained.Secondly,the proportion and distribution rule of spatial pattern elements(roads and buildings)of ancient villages in Tangdan Town in geological hazard risk classification maps and risk classification maps of various indicators are analyzed by using GIS,and to explore the correlation and mechanism between the geographical environment,natural disasters and the spatial pattern elements(roads and buildings)of ancient villages.Finally,the grid dimension is used to measure the spatial distribution of buildings and roads,and the law of spontaneously benefiting and avoiding the residents of ancient villages under the dual effects of environmental disasters is explored.Finally,the grid dimension is used to calculate the spatial distribution characteristics of buildings and roads,which proves the natural law of the ancient village residents'spontaneous pursuit of benefits and avoidance of hazards under the dual effects of environmental disasters.The results show that:(1)Based on the coupling model of grey correlation method and GIS technology,the establishment of geological hazard risk assessment system overcomes the subjective discrimination in determining the weight of evaluation index,and achieves the continuity of research units in research space.The weights of each evaluation index are:slope(0.1161),relative height difference(0.1158),annual average rainfall(0.1153),peak acceleration of ground motion(0.1146),vegetation coverage(0.1132),elevation(0.1122),hidden danger point distance(0.1091),river distance(0.1023),fault zone distance(0.1014).(2)In addition to vegetation,slope and earthquake peak acceleration,the proportion of road and building in low,middle-low and middle risk areas is more than 80%,and that of low,middle-low risk areas is about 70%.Comparing the proportion of road,building risk classification and geological hazard risk classification,it can be seen that there are three indicators with negative difference,and the difference is very small.It shows that in 66.7%of the indicators,the proportion of road and building in low risk,medium-low risk is greater than the sum of the proportion of low risk,medium-low risk in geological hazard.(3)Comparing and analyzing the proportion of dangerous roads and buildings in Tangdan Town and the proportion of dangerous roads and buildings in Tangdan Town,the changing trend of the two indexes is basically the same in numerical value.It shows that the roads and buildings in Tangdan Town are highly identical with the advantages and disadvantages of human settlements in spatial layout,and decrease along the high-risk environment in main body.(4)The roads and buildings in Tangdan Town have obvious fractal characteristics in morphology,showing a balanced and compact spatial distribution.This indicates that under the dual effects of disasters and environment,the spatial pattern of ancient villages has changed from the primitive Geographic Resources aggregation type to the balanced distribution type.It also proves the natural law of Tangdan Town's ancient villages'spontaneous pursuit of benefits and avoidance of disasters from the side.The wisdom of disaster prevention in spatial pattern.