Construction methods for cross passage in soft ground tunnels in China

In recent years, lots of soft ground tunnels, including metro tunnels and road tunnels, have been constructed in many cities in the east of China. Nearly all tunnels have cross passages between two tubes. In soft ground area, cross passages could be built in many kinds of methods, such as, cut-and-cover, mining methods, and combined method. Mining methods with help of ground improvement include grouting method, deep-mixing, high pressure jet grouting and ground freezing method. This thesis summarizes cross passage construction methods for soft ground conditions in China, in which the most successful and popular one, mining method with ground improved by artificial ground freezing and its risk prevention and safety protection measures, are introduced in detail.