Spatial Characteristics Analysis And Regionalization Of Debris Flow Induced By Rainfall In Liaoning Province

Debris flow disaster is a common natural disaster in Liaoning Province.For many years,it has brought great troubles and economic losses to local residents' production and life.In the past,research on debris flow disasters in the region focused on independent disasters,specific regions,or independent investigations on a single inducing factor.This paper makes full use of the powerful spatial superposition analysis module provided by GIS to statistically analyze the series of debris flow events induced by historical rainfall,and uses cluster analysis methods,combined with rainfall data,to study the environmental characteristics of mudslide occurrences and geologic features of frequently occurring areas.The correlation between natural-artificial binary combination and debris flow,such as topography,geology,rainfall,human activities,etc.,reveals the geographic characteristics and artificial characteristics of frequent and frequent occurrences of mudslides in Liaoning Province,with a view to scientifically and accurately predicting mudslides for related departments.The occurrence of an important theoretical support.Liaoning Province is a prone and disaster-prone province of debris flows.Most of the disasters are mainly distributed in the mountains in the southeast and areas with large undulations and abundant rainfall.Debris flow disasters in Liaoning Province are mostly caused by rainstorms.To cater for the “13th Five-Year Plan” proposed by the National Comprehensive Disaster Prevention and Mitigation Plan(2016-2020),we must shift from focusing on post-disaster relief to pre-disaster prevention and reducing disasters.The loss is transformed to the risk of disaster reduction,and the major shift from crisis management to comprehensive risk management.Based on the data of years of meteorological and hydrological data and historical mudslides in Liaoning Province,this paper based on the ArcGIS operating platform for the frequent occurrence of mudslides and frequent terrain.The overlay analysis of geomorphology,geological conditions,soil types,and land use conditions was conducted to study the natural geographical features of the debris flow area and to conduct zoning studies,with a view to providing scientific guidance for comprehensive management and reasonable control of regional geological disasters.The main findings of this paper are as follows:The characteristics of natural features of the debris flow prone areas in Liaoning Province are distinctive: the elevations are distributed in 150~1000m,and the distribution is more concentrated in about 500m;the slope is generally in the range of20°~40°;the types of soil are saturated and soils,Transitional red sandy soil,ordinary gray earth,dark-colored shallow earth,soft soft soil,latent leaching soil,artificial accumulation soil,and calcareous soil;various types of land use,including paddyfield,dry land,irrigation land,and Forest land,other wooded land,open forest land,medium-coverage grassland,bare rocky gravel land,and rural settlements,etc.,indicate that the intrinsic link between the debris flow prone areas in Liaoning Province and the surface cover conditions is not prominent;in addition,the dry land and medium coverage There are more outbreaks of mudslides at grasslands,woodlands,etc.,and some mudflats also occur in bare rocks and gravel lands.The average annual rainfall was 1331.15 mm from 1980 to 2016 in Liaoning Province,and the change rate was 0.2233mm/a.In the period from 1980 to 2008,the province had a total of 3 heavy gongs and 4 big gongs.In the mid-80 s to the end of the 1990 s,abundant rainfall caused more flooding disasters in Liaoning Province.This is in comparison with the time of the mudslides that have occurred.More consistent.The distribution of heavy rain and heavy rain in all regions of Liaoning Province is basically consistent with the distribution trend of multi-year average rainfall,that is,more southeast,less northwest,and decreasing from southeast to northwest.(3)Through the cluster analysis of historical debris flow disasters,it was found that the rainfall of the first type of debris flow disaster was not less than 50 mm on the day,the accumulated rainfall was no less than 50 mm in a single day,and the cumulative rainfall was not less than 65 mm in the first 7 days;the second type of debris flow disaster was induced.The rainfall on that day is not less than 70 mm,and the accumulated rainfall is no less than 70 mm in the past days,and the accumulated rainfall in the first 7 days is not less than 96mm;the rainfall on the day of the third type of debris flow disaster is not smallAt 25 mm,the cumulative rainfall every day is not less than 100 mm,and the accumulated rainfall in the first 7 days is not less than160 mm.The annual rainfall of the historical debris flow disaster,the cumulative rainfall in the first three days,and the cumulative rainfall in the first seven days were analyzed by inverse model,power model,and S model.The experience curve of debris flow in Liaoning Province was obtained: the amount of rainfall on that day and the previous 3rd and 7th days.The cumulative rainfall is better and the best three-day cumulative rainfall curve is best.The forecast is best for three days,and the first seven days can be used as a reference.