Analysis Influence Of Shield Tunnel Construction On The Neighboring Piles Foundation

For the shield excavation method, which is commonly used in subway, numerical simulation and empirical formula are both used to study the influence of shield excavation on ground deformation and piles foundation nearby in this thesis. On the basis of study results, influence factors on adjacent pile foundation are also researched, such as the ground loss rate, the pressure of soil chamber and the pile head constraints.The main conclusions of this thesis are:1. In the direction of tunnel axis, the ground subsidence area caused by shield excavation is achieved by the simulation calculation for construction process taking into account the disturbance of the excavation face, the pressure of soil chamber, the friction and grouting layer between the shield and the soil.2. The influence on the pile subsidence and bending moment caused by shield excavation are researched. The results indicate that the subsidence rate of pile reaches its peak and the bending moment achieves the maximum in the direction of the tunnel transverse when excavates to the pile position.3. The impact of ground loss rate and pressure of soil chamber on the pile subsidence is comparatively analyzed. These results show that the pile subsidence increases with the increasing of ground loss rate, but it increases with the decrease of the pressure of soil chamber.4. The influence of shield excavation on adjacent pile foundation is also researched based on the different pile constraints. The results show that the different pile constraints only have a greater impact on the upper pile deformation and bending moments, but have little effect on subsidence, additional axial force and lateral friction resistance.