Abstract:

The excess pore water pressure and ground surface settlement would be induced by rectangular pipe jacking tunnel construction. In this paper, the ground surface settlement induced by rectangular pipe jacking during construction phase is calculated by Peck formula. The calculation formula for excess pore water pressure of surrounding rocks is derived by stress releasing theory and stress transmission theory. The postconstruction ground surface settlement induced by dissipation of initial excess pore water pressure is calculated by layerwise summation method. The calculation method for total ground surface settlement after consolidation is proposed; and the relationship between ground surface settlement and time and that between ground surface settlement velocity and time are studied. The calculation results in case study show that: 1) The ground surface settlement velocity reaches peak after 3 months of construction, and then decreases rapidly. 2） The curves of horizontal ground surface settlement and total ground surface show normal distribution.

Key words: rectangular pipe jacking, initial excess pore water pressure, postconstruction ground surface settlement, soft soil stratum