Study On Rock Soil Mass And Ground Conditions Influence On Characteristics Of Debris Flow Deposit

The danger range of debris flow accumulation area is the basis for risk assessment,the maximum accumulative length,width and area is the important characteristic parameters of the dangerous range of debris flow.This paper takes the typical debris flow in Jiuzhaigou area as the research object,research on debris flow accumulation characteristics by means of on-site investigation,strength test and model test.Analysis of debris flow accumulation characteristics under the volume,bulk density,accumulation area slope and surface roughness coefficient contidion.Analye the sensitivity of the stacking process and Reveal the characteristic law of debris flow in this process,got the following conclusions:(1)volume is the main factor affecting the accumulation characteristics,followed by the density.In addition,the maximum accumulative length and width are more sensitive to the slope of the accumulation area and the roughness of the surface.The sequence of sensitivity analysis about accumulative length is:volume(Q)>bulk density(y)>area slope(?)>roughness((gc);The sequence by the accumulative width is:volume((Q)>bulk density(y)>roughness(<gc)>area slope(?).(2)The fluid property of turbulent debris flow are close to the Water-rock debris flow,the accumulation process is divided into three stages:initial deceleration,secondary acceleration and accumulation stop.Vertical bedding structure of debris flow deposit is positive sequence,planar structure is positive particale size.Mild~viscous debris flow's accumulation process are similar to turbulent debris flow,but the effect is lower,the vertical bedding structure of it is reverse sequence,planar structure is reverse particale size;Highly viscous debris flow is approximate retarded motion in stacking,no obvious segmentation,the deposits are irregular in both vertical and horizontal states.(3)Establish a predictive mathematical model of the maximum accumulative length,width and accumulation area,and select the typical debris flow in the study area and the Wenchuan earthquake area to test the model.The mathematical model in this paper has a high calculation accuracy in the prediction of the debris flow danger zone in the study area,and the calculated value of the debris flow in the Wenchuan earthquake area is small.Compared with the standard calculation formula for the single-ditch debris flow hazard range and the Wenchuan earthquake zone improvement formula,the mathematical model is more convenient.Replace the reserve of the deposit with the volume in the rainfall intensity,reduce calculation time.