Comparison Of Construcion Mehtods Of Loess Highway Tunnel

This thesis is combined tightly with Gu-Lang loess highway tunnel which is under construction. By data collections,field tests and the finite element program ANSYS,the author alylises the general problems existing in the design and construction of the loess highway tunnel. The author summarizes some ideas about how to improve the key construction techniques of the advanced rock structure and the arches.By sumarizing the monitoring technology of the loess highway tunnel construction in site and analysing the stability ,the author discovers some key construction techniques for the portal section of theâ…¤grade rock. Some reasonable guidances about how to carry out the excavation of the hole body are provided.Three-dimensional mechanical performance of primary support under different constructional conditions is analyzed by using numerical modeling method. By adopting three different excavation methods, which are named as full-face excavation method, benching cut method and double side heading method, respectively, the consecutive forces variations of the structures and the surrounding rock masses during the tunnel excavation is analysed ,and the quality of three methods are assessed.The author introduces the construction methods of highway tunnel and studies the main points of construction .Through construction simulation of the gradeâ…¤surrounding rock of highway tunnel and revalation of the application process of the finite element numerical simulation, the author shows the importance of the finite element method in the design of loess highway tunnels .With an engineering example,the author proposes key construction technical points of excavation and support of highway tunnel.