Stress and deformation mechanism of jacking prestressed concrete cylinder pipe under axial jacking force

Strengthening interconnection and interoperability between water supply groups and reservoirs in super mountainous cities, a large number of water conveyance tunnels need to be built. Jacking prestressed concrete cylinder pipe (JPCCP) has been applied to pipe jacking construction in soil stratum. A new type of JPCCP was proposed to meet the needs of long-distance pipe jacking construction of water conveyance tunnels in rock stratum. However, the frictional resistance of the rock mass-pipe interface is very complicated in engineering practice. It is common for pipe sections to become stuck due to the excessive friction. The mechanical response and deformation characteristics of the new JPCCP when pipe sticking problem occurred have attracted more and more attention. In this paper, the characteristics of concrete strain, steel stress, crack propagation and axial stress transfer under axial jacking force were studied by the combined method of fullscale test and numerical simulation. The full-scale tests results showed that the concrete internal strain and surface strain of the pipe increased with the increase of the axial jacking force. The spigot end was the weakest area, where cracks appeared first and then developed along the circumferential direction in the full-scale tests. The potential causes of pipe cracking in full-scale tests were carefully discussed. It is suggested to improve the mechanical performance of the spigot end. Finally, the numerical simulations further revealed the axial stress transfer characteristics of the new JPCCP.