Research On Critical Buried Depth Of Loess Tunnel And The Structure Behavior Of Section Geomorphological

Tunnel buried deep and shallow boundaries’ problems are concerned by Academicand Engineering, the standard in boundaries of the nature judgment surrounding rockpressure on self-supporting capacity of the tunnel lining is essential.By finite elementsimulation, and the tunnel depth of buried lateral pressure coefficient of variation ofjudgment at different depths, different span, different construction methods, different levelsof surrounding rock, and different tunnel spacing of the tunnel depth buried boundaries.People has found that the location prone to landslides, cave-tunnel face advancing to thered valley. For the lack of impact study of the section of the landforms on the constructionof the tunnel, three-dimensional numerical simulation of the different angles of slope,different excavation directions and the impact of flooding on the gully at the tunnelconstruction.Paper’s main conclusions as follows:1.Coefficient of lateral pressure with the change of tunnel depth is characterized bythe buried boundaries of the standard to reflect the tunnel depth. When the coefficient oflateral pressure near the surface does not appear to increase the phenomenon, a value closeto the initial lateral pressure coefficient is buried, contrary to shallow.2.By numerical simulation and combined with the dome side of the pressurecoefficient curves, come to the tunnel depth definition of buried and tunnel depth, span,hole type, wall rock, construction methods, tunnel spacing and other factors have a directrelationship.3.Numerical simulation and comparative analysis of different terrain slope drawn tothe ditch, two-way excavation, slope the greater the stress and displacement are larger;when the excavation of the ditch back slope the greater the smaller the top of the hill belowthe stress, shift the greater.4. Numerical simulation and comparative analysis of different excavation direction,draw a two-way excavation vault stress and displacement is significantly less than theexcavation to the ditch and back ditch, and the change is relatively stable, easy to monitor to prevent the sudden collapse of the tunnel.5. Tunnel excavation simulation comparison by flooding and not flooding the stateobtained after immersion in water tunnel excavation vault stress changes is much largerthan the not flooded condition, but after initial excavation impact the vault stress value isless than the non-flooded condition.