Abstract: To study the change in the segment load of largediameter pipe jacking under deepburied and high water pressure conditions, a case study is conducted on the pipejacking project of a power tunnel in Foshan, China. Further, the segment load and pore water pressure of the segment during pipejacking construction are measured and analyzed, and the results are compared with the theoretical calculation results in the current specifications. Then, the calculation method of segment load under grouting condition is deduced. The monitoring data and calculation results show the following. (1) The joint load of the segment is evenly distributed around the pipe wall, the top load is less affected by the grouting pressure, the bottom load accords with the grouting pressure, and the change of the bottom load is greater than that of the grouting pressure. (2) The state of pipesoil contact accords with the tunnel stability assumption during grouting jacking, and it fully accords with the pipesoil interaction assumption when grouting stops at the end of jacking. (3) Under the grouting condition, the segment load calculated by each specification is smaller than the measured values, and the pipe load calculation model by Terzaghi passive soil arch model is more reasonable.

Key words: largediameter pipe jacking, soil pressure, pore water pressure, pipesoil contact