Road Tunnel Portal Selection Based On Environmental Protection

The economy has developed fast in recent years ,the expressway network which as the main body of the highway has got a remarkable progress .The highway tunnels in the mountain areas are the most important part in the Transport facilities systems .Because of its special geographical position ,the environment effect, economic effect ,and the social effect of the highway tunnels has become the focus problems. In the paper ,we take the Environment protection of the tunnel portals as a key problems , also we consider the safety of the portal , and the economy of the portal at the same time .We make a preliminary discussion in this paper on how to choose a appropriate tunnel portal in the different conditions ,such as terrain, landform, geological condition, and ecological environment influence.There are six chapters in this paper. The main content include three parts. In part I:The outline of the highway tunnel construction in mountainous areas, introduced the environmental protection situation in present and the existence questions in portal construction. In part II:The classification and the trait of the portals, introduced the development of the tunnel portal, a new way in classification and the factors should be considered in the selection of the portal structure; In part III, the Analytical Hierarchy Process is applied to constructing a model of Portal evaluation, and with the help of this evaluation model ,an appropriate tunnel portal can be chosen easily and highly effective.The Analytical Hierarchy Process (AHP) is applied to appraising the portal model in the paper , and the classification of the portals ,the influence factors of the portal selection , and the characters of the different portal structure are all service for the method .On the base of the model , in order to realizes the intellectualization in portal selection, a system of portal selection is developed in the paper .With the help of the computer , we can make the project design,compare easy and useful. The conclusion may provide the reference for the engineering design.