Risk Evaluation Of Seiemic Landslides Based On Analysis Of Seiemic Landslides Information

Recently,the earth has entered the active period of earthquakes,and the frequency and disaster scope of earthquakes are increasing year by year.Landslides induced by earthquakes have caused a lot of casualties and property losses.China is one of the countries with active seismicity in the world,especially in the southwest area.With the further implementation of the western development strategy,the economic development of southwest China is very rapid,and the economic shock cannot be separated from the construction of infrastructure,especially the construction of expressways.However,at the same time of rapid construction,engineering construction is also facing the risk of earthquake and geological disasters,therefore,it is also very important to evaluate the risk of seismic landslides effectively.Based on the earthquake catalogue,strong earthquake station records and earthquake landslides data,this paper takes the influence area of Dayang high-expressway Chenghai fault zone in Yunnan Province as the research object,uses statistics,machine learning and other methods to carry out survey of unfavorable geological bodies,regional earthquake risk analysis,seismic landslides risk assessment and other work,and achieves the following main results:1.An earthquake of Ms6.5 occurred in Ludian County,Yunnan Province in 2014.The epicenter of the earthquake was 300 km away from Chenghai area.In this paper,720 landslides data of Ludian earthquake were taken as samples,and statistical analysis and support vector machine model were used to establish regional landslide risk assessment model.In order to ensure the accuracy of non-landslide samples in support vector machine model,firstly,the statistical method is used to analyze the characteristic relationship between landslide and each influencing factor,then the fractal theory and landslide distribution density are used to calculate the landslide risk index of each influencing factor interval,and 720 non-landslide samples are determined from the influencing factor interval with low landslide risk index.Finally,based on the support vector machine,the regional landslide risk assessment model can be established.The optimal parameter ? is calculated as 0.1 and the penalty factor C is 0.2.At this time,the highest classification accuracy is 81.25%.The results show that 68.1% of the actual landslide points fall in the area where the landslide risk is more than 60%,which verifies the accuracy of the model.2.Based on the G-R model,the upper limit model of regional potential magnitude is established by using the earthquake catalogue of Chenghai area in recent ten years,and the maximum magnitude of Chenghai area is Ms 6.6.Then we select 45 groups of strong earthquake station record data of Ludian Ms6.5 earthquake,and establish the logarithmic correction model between the theoretical value of attenuation formula and the observation value of the station.Based on the modified model and the attenuation formula of ground motion,the peak acceleration distribution of Chenghai potential Ms6.6 earthquake is evaluated.3.The possible unfavorable geological bodies in the influence area of Dayang high-expressway Chenghai fault zone were evaluated in the field by the methods of UAV and high-density surface wave.Based on the analysis of the topography and geology of the slope,it is preliminarily evaluated that there is the possibility of reactivation of the ancient landslide in the damieju area of Chenghai,the risk of gully collapse and boulder collapse in the eighth generation area,and the possibility of broken rock collapse in the Taoyuan area.And the bad geological body causes the hidden danger to the project of Dayong high expressway,which makes clear the necessity of risk assessment of regional earthquake landslide.4.The landslide risk assessment model is applied on the seismic landslide risk assessment of the area affected by the high-expressway Chenghai fault zone.The evaluation results show that 7.2% of the area of 6050 km 2 around the Dayong expressway has a very high landslide risk with a probability of more than 80%,and48.2% has no landslide risk.However,there are 3.2km of Dayong expressway which is126 km has a very high landslide risk,and other areas are located in low-risk or nondangerous areas.At the same time,according to the evaluation results,there is a high risk of landslide in the area with bad geological body distribution.Considering the impact of landslide on the project of Dayong expressway,corresponding engineering prevention measures are proposed respectively.