ABSTRACT
Because of their many merits such as low disturbance to surroundings, high advance rate and safety, pressurized-face tunnel boring machines (TBMs) are widely used to excavate metro tunnels in urban areas throughout the world. TBM launching is a challenging work especially in crowded area where ground reinforcement isn’t allowed or only partially fulfilled. To solve the problem, machines were launched under the protection of a closed steel sleeve, and the launches won success in the cities such as Guangzhou and Shenzhen of China. Based on an earth pressure balance TBM launch in Shangmeilin metro station site in Shenzhen, the launch under the protection of a closed steel sleeve is presented and explained. With the subsurface instrumentation, the earth pressure and pore water pressure was monitored over the whole period of TBM launching. The ground response is investigated with the recorded results. The findings can provide valuable references for similar projects.
