Numerical Simulation Study on Three-Step Method Construction for Neighborhood Tunnel

When crossing difficult terrain or extreme regional geological conditions encountered, there are difficulties in laying road routes, the spacing between two adjacent tunnels is limited. Neighborhood tunnel is a form of tunnel structure between separate and arch ones, less affected by the topography. It is more conveniently and easier to control the cost. Surrounding rock deformation mechanism with construction of three-step method is more complex, and therefore a reasonable means of construction technology and support is essential. Taking a certain neighborhood tunnel highway engineering background, aimed to provide guidance for follow-up monitoring and support, we use numerical simulation software FLAC3D on three-step method excavation construction. Rational creep analysis of geotechnical model and calculation parameters is selected. It helps to calculation and analysis the mechanical response of tunnel surrounding rock characteristics and clarify the tendency of displacement and stress fields.