Study On Highway Engineering Zoning And Zoning Index System In Loess Area

Loess plateau locates in inland China,and distributes in Gansu,Shaanxi,Shanxi,Henanand the other provinces.It is the largest region in the world which piles up loess.The loesshas great thickness,complete loess strata and clear fossil soil in the area.Loess plateau isfamous for its obvious regional characteristics such as broken terrain,loose soil,crisscrossgullies,complicated soil properties and special climate.With highway construction rapidlyentering the economic underdeveloped regions of western provinces,especially in the loessplateau areas,not only the project quality should be ensured,the cost and highway diseasesshould be reduced,but also the coordination between the highway construction and naturalenvironment should be achieved from the aspect of the sustainable development.Withartificial works constructed in different natural environment,highways pass various naturalgeographical areas.Highways are affected by natural environment factors,at the same timethey will affect the natural environment.This interaction is more obvious in the fragileecological environment of loess plateau.The differentiation law of natural factors and internalmechanism of interaction between highway construction and natural environment factors arerevealed.And then a reasonable nature zoning is achieved.Those are the fundamental basisfor highway network planning,designing,construction,maintenance and operationmanagement.And also a reasonable nature zoning indicates practical significance forhighway construction in loess area.Firstly,summarizing and analyzing the related research results of engineering zoning athome and abroad,combining with the actual situation of highway construction in the loessarea,it is determined that surface configuration index,erosion intensity index,slopestability index and loess collapsibility should be considered when road engineering zoning iscarried out in loess plateau.Secondly,the calculation elements of zoning indexes are defined.The calculation commensurability platform and calculation formula are established.Singleclassification maps of surface configuration index,erosion intensity index,and slope stabilityindex are obtained after quantitative calculating of zoning index.Referring to thecharacteristics of highway construction,the zoning maps of loess collapsibility is drawn by analyzing and summarizing research results of different fields.Thirdly,referring to thecharacteristics of highway construction,comprehensive zoning of highway is made on thebasis of zoning index calculation and classification.The loess plateau is divided into threezones and twelve subregions,and the corresponding highway zoning maps are drawn.Thezoning conclusion will provide theoretical guidance and reference in practice for highwayplanning,designing,and constructing.At last,GIS technique is used in highway engineeringzoning.It digitalizes the whole process of engineering zoning.The quality and accuracy ofzoning is improved by using GIS,and it is a good attempt for zoning work.