Abstract:

In order to study the ground settlement law and the interaction between jacking pipes during smallspacing circumferential group pipe jacking, the ground settlement caused by pipejacking is analyzed, and the value of ground loss ratio and the empirical formula of settlement trough width coefficient during smallspacing circumferential group pipe jacking are put forward by taking the piperoofing project of Gongbei Tunnel of Zhuhai Connection Line of Hong KongZhuhaiMacau Bridge for example. And then the influence of fore pipejacking group on strata loss and maximum ground settlement induced by followed pipejacking group is analyzed by numerical simulation. The analytical results show that: (1) The ground settlement caused by the pipe jacking of Gongbei Tunnel is within the control requirements. (2) With the increase of buried depth of the pipe, the settlement trough width coefficient caused by the single pipe increases, while the maximum ground settlement decreases; the initial ground loss ratio during pipe jacking is 1.5%. (3) Due to the promotion of technical proficiency and the reinforcement effect of fore pipejacking group, the average ground loss ratio after jacking of all 37 pipes is ultimately controlled to 0.8%, and the ground settlement has been effectively controlled.

Key words: Gongbei Tunnel, pipe roof, pipe jacking, ground settlement, ground loss ratio, settlement trough