Study on shear performance of new ring joint with sleeve and bolt for shield tunnel
In order to optimize the shear capacity and locate function of the joint in large-diameter shield tunnels,a hollow sleeve was designed to be installed at the bolt hole of the ring joint. To investigate the shear performance of the new "straight bolt+sleeve" ring joint,a three-dimensional numerical model of the ring joint was established using Chengdu Jinxiu Tunnel as a reference. Full-scale experiments were conducted to validate the accuracy of this numerical model. The results indicate that during shearing,the new ring joint underwent three stress processes:friction section,shear section,and failure section,with its shear stiffness nonlinearly evolving during each stage. The sleeve significantly enhanced the shear performance of the joint,and smoothly transferred excessive shear loads to the bolt,thereby preventing abrupt segment slippage and providing protection for segments. The force coordination mechanism between sleeve and bolt was as follows:when small misalignment occurs,sleeve deforms elastically and primarily sustains the shear force;as displacement increases,sleeve gradually entered plastic state while the bolt bears main shear force. The addition of the sleeve can significantly enhance the control capability of the ring joint during micro-misalignment stage. Furthermore,due to its inherent orientation and positioning function,it can effectively reduce both the occurrence rate and quantity of the misalignment in segment assembly stage. The full-scale tests demonstrate that the failure modes of the new ring joint are as follows:the sleeve and bolt failed when they entered the plastic state,while symmetrical shear failure took place within the segment with the bolt hole as the center at an angle of 30°～45° from the horizontal direction. Moreover,it is worth noting that the concrete near the bolt hole on the inner arc side of the segment represents a weak area. These research findings could potentially serve as valuable references for future engineering applications involving this type of joint.
shield tunnelring jointnumerical simulationshearing resistancefull-scale test of ring joint
万方数据
维普
