The Type Selection Of Shield For Nanjing Metro

Shield machine, as the large comprehensive hi-tech construction equipment especially for tunneling, posses the advantages of quick heading, excellent quality, safety, economy, being beneficial to the environment protection and reducing the labor strength, which can be applied from the loose soft ground, silt to the hard rock. While the construction of tunnel works is frequently restrained by many factors especially in the cities. It is the optimum option for using shield machine to build tunnels or metros concerning of the forest of ground buildings and busy traffic in the city.The type selection and allocation of shield machine, as a comprehensive work, is one of the key links in the tunneling for adopting the shield construction method. For the type selection of shield machine, the engineering geology, hydrography, construction period, economic factor, environment protection and safety shall be put into whole consideration, so as to select the appropriate machine type and allocate the reasonable auxiliary equipment to ensure the smooth completion of the tunnel works. There are many successful examples for the type selection of shield machine in China as well as much experiences and lessons. This paper put forwards the method and procedure for machine type selection based on the engineering condition, geology and progress requirement of the section tunnel in Nanjing Metro. At present, the selected shield machine has smoothly completed one section tunnel. Through the actual performance, the shield machine is in good condition verified that the selected machine is very successful.