Research On Route Technical Standard Of Highway Upgrading And Reconstruction In Grassland Area

China has a lot of grassland in Western Minority Area. To speed up Western Minority Area economy development, our country has carried out the policy of developing Western Minority Area economy and implementing Western Development. The highway construction investment has increased to develop Western Minority Area economy. As the area of the most grassland characteristic, highway construction of Inner Mongolia Autonomous Region developed fast and obtained unprecedented achievements. There are about 2000 kilometer first grade highway demanding upgraded to expressway, according to expressway net development planning of Inner Mongolia Autonomous and our country. We will face many technical problems that are important and desiderate to be solved during the upgrade process in grassland areas. This paper researches route technical standard encountered during upgrading first grade highway to expressway in order to guide projects of upgrading first grade highway to expressway in grassland areas.The background of this paper is the more than 1300 kilometers first grade highway in Inner Mongolia. Through investigation and analysis, this thesis systematically summarizes route alignment, construction standard, project scale, natural attribute along the roads, alignment technical standards, subgrade width and composition of cross section, traffic condition on operation and traffic accident of inter-province highway in the Inner Mongolia Autonomous Region. The article summarizes characteristics of first grade highway in grassland by studying physical geography and economic characteristics of grassland, and puts forward a technique of evaluating upgraded first grade highway alignment index adaptability using fuzzy mathematics theory based on current highway alignment standard and criterion of our country. The paper has systematically analyzed upgraded highway's traffic capacity and service level using modern traffic theory.Through analysis of the causes and control factors of upgrading first grade highway to expressway in grassland areas, the paper also researches the major factors that decide upgrade transformation form and standard choice, thus puts forward the upgrade transformation form in grassland area and adaptive technical standards. According to China's highway design motto of promoting the "safety, environmental protection, comfort, harmony" new ideas, the article researches overall design, grade separation, auxiliary road, toll mode, service area layout, emergency vehicle road and safety design principles in grassland first grade highway upgrade to expressway. Combining the specificity and complexity in grassland first grade highway upgrade to expressway, the need and requirements of flexible design and dynamic design are proposed. The paper also summarized the management methods and notable points in survey and design.The paper analyses domestic and international research results about highway project safety evaluation researches the evaluation model and evaluation criteria in grassland first grade highway upgrading and rebuilding using the method of operating speed in "Highway Project Safety Evaluation Guide", and proposed speed correction model considering changes in cross-sectional sections and the long-bending-slope sections of road, so that the evaluation methods of the operating speed can be applied in the upgrading of roads, to ensure the continuity and consistency of highway alignment design.With practical engineering examples, the article studies the procedures and methods for the implementation of first grade highway upgrading and rebuilding in grassland areas, and verifies the feasibility of the results, namely issues such as adoptable forms and technical standards for Inner Mongolia grassland first grade highway upgrading into express way, and evaluates safety of sample projects, gives out evaluation conclusions, recommendations and comprehensive measures.