The Effect On Tunnel Support Structure And Ground Settlement By Stress Release And Excavation Method

With the rapid development of road transportation, tunnel constructions have been widely used. As the same time, more and more problems existing in tunnel construction appear to our face, how to control the ground settlement effectively and make the loading distribute reasonably on the support structure become to be an urgent problem that needs to be solved. Modern tunnel construction technology is based on the New Austrian Tunneling Method, which thinks the rocks have a certain self-supporting capacity, that are parts of tunnel support structure system. Therefore, it is very important to make full use of the rock self-supporting ability to maintain the stability of surrounding rock. The paper simulates the response mechanism of buried tunnel under the different surrounding rock stress release and different excavation methods through the ANSYS software, the main content is as following:(1) Sum up the rock stress calculation methods in tunnel excavation step and support step, introduce the characteristics and the application conditions of different tunnel excavation methods which usually be used.(2) Use the parametric design language APDL to write the order"free surface nodal extracted and reverse-graded to impose"to achieve the rock stress progressive release in the tunnel excavation process; get the force characteristics of support structure and the ground settlement distribution regular.(3) Use the order for element life and death to simulate the different tunnel excavation methods, obtain the different tunnel excavation effect characteristics on support structure and ground settlement.(4) Establish finite element models with different excavation methods based on LiuYang River tunnel, analyze and contrast the actual measurement data and the simulation data, make use of peck formula to compute the unit ground loss.