Preliminary Design Research On The Scheme Of Second-grade Highway Of National Road 327 From Tuji In Luochuan To Huangling

The National Road 327 is the east-west national road in the southern part of Yan'an City.The National Road 327 passes from Shanxi into the Hancheng city in Shaanxi,then passes through Huanglong and Huangling in the west,and at the place of Shuanglong Town,it turns into the territory of Xunyi in Xianyang.The line connects searals of economic core areas such as Huangling County,Tianzhuang Town,Diantou Town and Shuanglong Town.The completion of this project will completely solve the vehicle transit problem and play an important role in relieving the traffic pressure in Huangling County.The paper first introduced the role of National Road 327 in the road network of Shaanxi Province and its connection with surrounding roads and discussed the function of the construction of this contract tenders to improve the transportation network of Huangling County and promote its regional economic development.Afterwards,based on the engineering feasibility report,approval opinions,actual conditions and the opinions of the owners and experts,the direction of the route and control points wre clarified and two schemes for the Mashan-Jade section were proposed.Through the analysis of the horizontal and vertical indicators,engineering geology,environmental impact and other factors,the recommended scheme was determined.And the operation speed was analyzed to ensure safety.Then the construction conditions of the recommended scheme were discussed,and along the route,the geological structure,stratigraphic lithology,meteorology,hydrology,and some major engineering geology issues were evaluated.Finally,to verify the feasibility and rationality of the recommended scheme further,detailed descriptions were given on the subgrade,pavement,drainage,bridges and culverts,route crossings,safety facilities and environmental protection and some other professional engineerings.The conclusion was drawn that during the preliminary design of mountain roads,various control factors and constraints must be comprehensively considered.Not only should comparisons be made on the route indicators,but they must be selected in many ways,especially in the case of engineering geological conditions,and its impact will run through the entire process of the project,including later safety operations,which needs to focus on analysis and demonstration.