The Simulation Of Mud Flow Susceptibility Based On TRIGRS Model In Fu County,Shannxi Province

In July 2013,there was a heavy rainstorm in yan'an city,and fu county was at the center of the rainstorm.The heavy and prolonged rainfall led to the loess mudflow disaster at the exit of yanmaigou tunnel,which nearly paralyzed the expressway.This shows that mudflow is one of the most important geological disasters on the loess plateau in northern shaanxi,and the degree of damage cannot be underestimated.Based on this,this article refer to the related literature at home and abroad,on the basis of predecessors'research,comprehensive mud flow disaster investigation,choose county,shaanxi province rich wheat export 5.8 km~2 around the tunnel as the study area,using the laboratory test to obtain the mechanical properties of soil and hydrological parameters,finally using TRIGRS model and ArcGIS software making evaluation of mud flow is used in the study area,and get the following conclusions.(1)The TRIGRS calculation results are as follows:when the working condition is 7.5mm/h rainfall intensity and 12h rainfall duration,the number of grids in the unstable slope area of the study area is 254,accounting for 0.417%of the total area of the study area.When the working condition is rainfall intensity 10mm/h and rainfall duration 12h,the number of grids in the unstable slope area of the study area is 604,accounting for 1%of the total area of the study area.When the working condition is rainfall intensity 15mm/h and rainfall duration 12h,the number of grids in the unstable slope area of the study area is 939,accounting for 1.54%of the total area of the study area.(2)Analytic hierarchy process(AHP)is used to calculate slope in the study area of mud flow effect value of the liability,and the results are as follows:to define the study area of 30°~50°slope gradient of mud flow liability influence of 1.<8°and>50°area affect the value of 40.2,8°~15°area affect the value of 8.7,15°to 30°area affect the value of 2.7,the greater the numerical show that mud flow is not likely to happen.(3)On the basis of previous studies on the starting conditions of mudflow in the study area,the runoff depth at the start of mudflow in the study area was calculated to be at least 47.96mm/h.ArcGIS software was used to calculate the runoff on the slopes in the study area,and the influence of rainfall intensity on the susceptibility of mudflow was obtained.(4)In ArcGIS using raster calculator,TRIGRS model to calculate the rainfall induced slope stability results in the study area and weight after the classification and assignment is multiplied by the slope,flow results in the study area,result of calculation is the mud flow in the study area liability as a result,when the condition of rainfall intensity 7.5 mm/h,12 h,rainfall duration mud flow is used in the study area regional grid number is 82,accounting for0.134%of the total area of the study area;When the working conditions are rainfall intensity10mm/h and rainfall duration 12h,the number of grids in the mudflow prone areas in the study area is 126,accounting for 0.206%of the total area of the study area.When the working condition is rainfall intensity 15mm/h and rainfall duration 12h,the number of grids in the mudflow prone areas in the study area is 401,accounting for 0.658%of the total area of the study area.