| Road erosion is widespread in the loess hilly-gully region,which has become the main source of sediment production in the region,restricting the construction of regional ecological civilization and sustainable development.In this paper,the response of different types of road pavement to rainfall and underlying surface characteristics was studied in Fangta watershed of Ansai District,northern Shaanxi Province,and the hotspot pavement types of road erosion were identified.The physical connectivity between roads and the catchment above them and the response of hydrological connectivity strength of different paths to rainfall were investigated,and the aggravating effect of hydrological connectivity in the catchment above them on road erosion was revealed.This study provides a scientific basis for the prevention and control of water and soil loss on the road in the watershed.The main conclusions are as follows:(1)Roads in the basin are mainly concentrated in the sub-basins with frequent human activities,and agricultural roads are the main road type,accounting for 70% of the total road length.The average branch ratio of the road is 3.73,the bending index is concentrated between1.1 and 1.6,and the average slope is concentrated between 10° and 15°.(2)The pattern of erosion rate of different types of road surfaces is as follows: petroleum transportation road > agricultural road > abandoned road,soil road > soil-rock mixed road >plant road,inner turning road > outer turning road > straight section,newly built road > newly renovated road > unrenovated road.Road surface erosion was positively correlated with rainfall and rainfall duration(P < 0.05).(3)There was a significant positive correlation between pavement erosion and its length,area and slope factor(P < 0.05),and a significant negative correlation between pavement soil bulk density(P < 0.05),but no significant correlation between pavement erosion and road width(P > 0.05).Slope types also has great influence on pavement erosion.Convex slope has higher erosion risk.Pavement covered with vegetation or drainage measures can effectively reduce pavement erosion.(4)When the land use type of the catchment area above the road is terraced,the erosion amount of the road below is smaller.Road surface erosion was negatively correlated with the vegetation coverage of the catchment above the road(P < 0.05),and positively correlated with the catchment area(P < 0.05),but the average slope of the catchment had no significant effect on road surface erosion(P > 0.05).(5)The hydrological connectivity between the road and the catchment above it presents the order of heavy rainfall event with long duration and high intensity > heavy rainfall event with long duration and high intensity > small rainfall event with short duration and high intensity > small rainfall event with long duration and low intensity.The rank of road erosion degree under different hydrological connectivity was strong and medium connectivity > weak connectivity > no connectivity. |
