Study On Site Type Division And Vegetation Allocation Of Highway Slope In Chengde Area

Highway construction inevitably forms a large number of exposed slopes,which leads to serious ecological and environmental problems such as vegetation damage,soil erosion and debris flow.Vegetation restoration is one of the important countermeasures to achieve sustainable development of highway construction.Taking the slope of the trunk highway and their surrounding mountain in Chengde area as the research object,basing on the field conditions and vegetation survey,the highway slope type and vegetation restoration species are classified by the principal component analysis and analytic hierarchy process(AHP).It will form a vegetation restoration system for highway slopes in Chengde area.The analysis results are as follows:(1)Selecting 57 slope samples to conduct site surveys and soil sampling for laboratory tests analysis in airport connecting line,Pingquan-Liaoheyuan tourist highway,Kuanbang line,Xingjian line,Jinxing line,National Highway 101 and Yuda line in the Chengde area.The filling method,topography and geomorphology,and slope composition chosen as the qualitative factors for highway slope division.The highway slope is divided into 7 site type groups,including Mountain stone highway slope,Hilly stone highway slope,Plain stonehighway slope,Mountain soil and Stone mixed roadside slope,Hilly soil and stone mixed roadside slope,Plateau soil and stone mixed roadside slope and Mountainous soil mixed stone embankment slope.On this foundation,22 site types are obtained by selecting the dominant factors of each site type group based on the principal component analysis.(2)Analyze the growth,ecology and distribution characteristics of shrubs and herbaceous plants in Chengde area through the investigation of mountain plants along the slopes and trunk roads.There are 35 primary plants species in the area of vegetation restoration on the highway slope of the region,according to the calculation results of important values to remove common weeds and invasive plants.And the primary plants species included 11 shrubs and 24 herbaceous plants.(3)Following the basic principles of ecological restoration and suitable tree adaptation,the AHP is used to construct a plant selection system for vegetation restoration on highway slopes.After expert scoring and qualitative analysis,the optimization and sequencing of the vegetation restoration species of highway slope in Chengde area is obtained.Finally,the optimal vegetation allocation for vegetation restoration for different site types is determined,following the allocation principles of species diversity,shrub and grass blending,people-oriented,and landscape coordination.