Analysis on performance of large diameter concrete jacking pipe

The load model and its design method of a pipe are to be improved. Based on the South Line project of sewage treatment in Shanghai, the performance of inner diameter of 4 m jacking pipe was studied by numerical simulation. The variation of contact pressure between pipe and soil during construction was analyzed, and the influence of covering soil depth was then discussed. The differences of the load model from the technical specification for pipe jacking of water supply and sewerage engineering were researched, and the differences of the internal forces were compared. The results show that soil arch effect is strengthened with increasing of cover soil depth, while the distribution of contact pressure is more uniform than the codes. Therefore, the active earth pressure is conservative to calculate lateral pressure, and the subgrade reaction could be also more uniformed. The bending moment of pipe will decrease while the axis force increase if the load model is improved, which would optimize the design method of pipe.