Numerical Simulation And Monitoring Measurement For Construction Of Highway Tunnel With Small Spacing Entrance

The Highway tunnel with small spacing entrance to cave a term of stratum thinner, belonging to strong effloresce band, wall rock generally more broken, and usually clipping soil layer, for this kind of disadvantage condition in soil arch, how reasonable exploitation every kind of construction method, while insuring the safe premise, lower the engineering cost, increasing work efficiency. meanwhile, the broken mechanism that enhance to the rock strata is studied in this paper, the influence of vary construction methods to wall rock have a detail research, these problems need to solve urgently. But obtains accurate data and so on geological, surrounding rock and design-load parameter is extremely difficult, in the quite long historical period, the tunnel design based on the experience primarily.This paper which based on the monitoring measurement design and implementation during construction of the Highway tunnel with small spacing entrance, gained in the construction process the monitoring measurement information; according to the information and the laws gained through experience and theory analyzing to estimate the rock stability of ground-support system and adjust the support time and the support parameter appropriately. Adopting FEM to carry out 2D numerical analysis on the construction process. At those cases such as different depth and different spacing, to confirm the influence to the rock stability at the entrance of the small spacing tunnel. And contrast the advantage with different construction methods. Using 3D FEM model to simulate the vary character of surrounding rock stress, support bearing, and ground surface settlement on the construction process.This paper mainly includes contents as follows:1. Through the investigation research and numerical simulation, this paper confirms the appropriate support method and excavation method at the entrance of the Highway small spacing tunnel.2. According to the information gained at the site test, the stability of the ground-support system is analyzed and estimated.3. Adopting 2D FEM to analyze the mechanical character and the stability of the small spacing tunnel. Establish the interaction of the small spacing tunnel during the construction process. According to the analysis to the plastic zone of the center pile, establish the condition to strengthen the center pile.4. According to the 3D FEM numerical simulation, this paper analyzes the surrounding rock stress, convergence of tunnel inner perimeter, support bearing, and ground surface settlement, establish the safety and the justification of the construction.