The Theory And Numerical Analysis On Plastic Zone And Ground Arch Due To Tunnel Excavating In Bearing Soil

The construction of tunnel in the urban environment, because of urban space constraints, is often forced to bulk nearby some building foundations. Construction of the tunnel will have an impact on the surrounding environment, disturbing soil and causing uneven settlement of building foundation,which,if excessive,would not only effect the aesthetic of architecture,but also do harm to the structure safety. At the same time, the foundation load will change the plastic zone surrounding the tunnel and the form of ground arch. An Analysis on the impact of foundation load on the plastic zone surrounding the tunnel will help determine the impact of tunnel and building foundations. To determine the form of ground arch will help determine the load on the tunnel lining. Therefore, the main works of this paper are listed as follows;1. Use of analytical solution for predicting the ground settlement induced by tunneling in free soil and Plasticity Yield Criterion get the calculation process of analytical solution for predicting the plastic zone induced by tunneling in free soil. Then study the influence on plastic zone due to tunnel depth, tunnel diameter and soil parameter. Comparison between analytical solution and numerical solution is made to verify the applicability of analytical solution.2. to get the calculation process of analytical solution for predicting the plastic zone induced by tunneling in bearing soil, by superposing Boussinesq or Mindlin solution and the solution for predicting the ground settlement induced by tunneling in free soil. Then study the influence on plastic zone due to different load, giving the region, in which load can easily cause plastic zone around tunnel.3. to get calculation process of analytical solution for predicting the shape of ground arch in bearing soil by studying the theoretical solution for Calculating the shape of ground arch in free soil and Considering the effect of load. Then study the influence on ground arch due to load.