Mechanical Properties Resaearch on the Recyclable Anchor Cable of Dry Dock Foundation Pit in Immersed Tunnel

To clarify the mechanical properties of recyclable anchor cable of dry dock foundation pit in immersed tunnel during excavation and operation process, the action mechanism of recyclable anchor cable of dry dock foundation pit was analyzed based on a typical engineering example. The fine simulation model of recyclable anchor cable was established by numerical method. The stress and deformation characteristics of the pit supporting system were calculated and revealed. The mechanical properties of anchor cable were compared with that of ordinary anchor cable, and revised design ideas of recyclable anchor cable were proposed. The results show that the displacement of supporting structure and the axial force of anchor cable are both less than the standard limit, so the foundation pit is in a safe and stable state. The recyclable anchor cable axial force presents a uniform "rectangular" distribution, rather than the monotone decreasing curve distribution proposed by existing researches. In the process of storage and drainage in the dry dock, the effect of the reciprocating water pressure on mechanical properties of soil and anchor cable is significant, which should be fully considered in actual engineering. The deformation induced by storage and drainage is recoverable elastic deformation, and the amplitude of the internal force of the anchor cable increases gradually from top to bottom. Compared with the ordinary anchor cable, the recyclable anchor cable has weaker ability to restrain the lateral movement of foundation pit and meanwhile internal force is greater than that of ordinary anchor cables as well as the distribution law of the axial force is different. The axial force in the anchorage section of ordinary anchor cable distributes in the form of "ladder". In practical engineering, the internal force design of recyclable anchor cable can refer to the conventional design idea, and then meet the bearing requirements through modification.