Selection and distribution of ground loss ratio induced by shield tunnel construction

The observed data of surface settlement caused by construction of Qingchun Road River-Crossing Tunnel in Hangzhou are collected, and a method to select surface settlement values during the construction stage is put forward. Based on the data of ground loss ratio induced by shield tunnel construction in Beijing, Shanghai, Nanjing, Guangzhou, Wuhan, Tianjin and Shenzhen, seventy-one groups of data are statistically analyzed. The results show that the ground loss ratio ranges from 0.2% to 3.01%. About 95.77% of the ground loss ratio is 0.20%～2.0%, and about 43.66% of the ground loss ratio is 0.5% ~1%. The ground loss ratio is 0.20%~2.0% for the cohesive soil area. The ground loss ratio is dependent on the construction level, soil properties and buried depth of the tunnel. With the increase of the tunnel buried depth, the ground loss ratio overall decreases, especially when the buried depth is more than 25 m. The relationship between the ground loss ratio and the tunnel buried depth can be approximately expressed by power functions.