The Exploration Of Route Design Tactics In Steep Topography Mountainous And Disaster-prone Areas

Route design in Dangerous mountainous and disaster-prone areas is a complex engineering.On the one hand,route design is a multidisciplinary system.On the other hand,the high mountains,deep valleys,the steep topography and the disaster-prone situation are the characteristics of China’s western mountain area and it brings further difficulty to route design.According to the plan of the’’mid-long term railway network plan”,The railway network in China will continue to extend to the West of China in the future,and because of the demand by” The Belt and Road traffic” infrastructure construction,the transportation corridor from West China to South Asia will also be included in the construction plan.These are difficult problems that have never been encountered in the history of engineering construction in China and even in the world.In today’s mountainous area route design process,the judgement of the merits and faults of the route plan is still based on experience.There are only a few principles in the existing design codes for disaster reduction and route selection,and the systematic theoretical system is insufficient.Therefore,this paper selects several typical cases of the route design and scheme decision of the existing mountain alignments,analyzes and summarizes the main points of the disaster reduction tactics,striving to propose a more scientific guiding ideology for route design in disaster prone mountainous area.The paper is divided into four themes.The tactics of route design in disaster prone mountainous areas and steep topography areas is discussed respectively.Subject one is the tactics of railway design for disaster reduction in debris flow area.First of all,the paper takes the Dongchuan branch railway as an example to analyse the disaster of the existing railway and its reason.By means of Contrast the existing and new railway,the paper comes to a conclusion that railway should first consider elevation avoidance in strong branche and weak mainstream area.Secondly we propose that railway can use Moraine platform on piedmont of mountain to avoid glacial mud-rock flow disaster in Parlung Zangbo basin,and Its feasibility is also demonstrated.Subject two is the tactics that move the tunnel inwards to avoid large disaster point.The paper takes the 102 tunnel in No.318 National Road as an example to analyse the disaster of the existing road and its reason.Then the paper comes to a conclusion that the route along the river should use tunnel to avoid disaster when pass through large disaster point.Subject three is the tactics that how to overall planning the length of tunnel and route development in disaster-prone mountain areas.The paper takes the tunnel of ErLang mountain in No.318 National Road and the Medog tunnel as an example to analyse the advantage of long tunnel scheme in construction,operation and diaster-reduction.Subject four is the tactics of railway design for pass through extremely large elevation difference obstacle such as Himalaya mountains.The paper use the example of China-Nepail Railway as an example.Firstly,we analyse the formation reason of Bangxing platform besides the Gyirong Zangbo,and demonstrate its stability to be a station.Then we put forward a suggestion that railway can use Parallel river system in southern slope of Himalaya mountans to design a “U-shaped” route development which spans across different basins.Finally,a comprehensive evaluation is made for the route scheme and the significance of railway construction is also analyzed.