Shield Construction In Complex Formation And Its Impact On The Surrounding Environment

So many subway tunnel will be built in composite floor of complex geological conditions, because large number of urban underground space was been developed. And the formation had great different, so the construction of the shield had higher requirements: tunnel shield was able to adapt to construction in a variety of complex formation, the choice of construction parameters compatible with the formation characteristics, tunnel construction should minimize the impact on the surrounding environment (ground and building). Study of shield construction in complex formation and its impact on the surrounding environment had great significance to ensure the safety of construction when shield was in a complex environment and the protection of the surrounding environment.In this paper, range between Cha Lu Kou and Nanjing South Station in the southern extension of Nanjing metro one line was as engineering background, analyzed the composite shield technology and its adaptability to complex formation respectively; studied shield parameters by complex formation and props wear; researched implication of ground and building when shield through a variety of complex formation through on-site monitoring; simulation studied heterotaxy when shield construction was in composite ground, and analyzed the impact on the surrounding soil of advancing in various composite formation using finite element software.(1) Studied adaptability of composite shield and ground, through analyzing related geological conditions in this range.(2) Got parameter setting principles and rules of shield tunneling in the complex formation through statistical analysis of parameters in actual construction process.(3) Measured by on-site analysis obtained that composite stratigraphic sections of the combination of different forms of face formation, the surface displacement showing different settlement rules.(4) Simulation of shield composite construction by finite element software, we got: top soil conditions was the main factor that affect surrounding soil disturbance level of shield in the soft strata under the hard composite. When the upper soil was softer the surface subsidence was greater, and the scope of the settlement was greater.