环缝直螺栓复拧对盾构隧道接头力学性能影响试验研究OA

To improve the effectiveness of differential settlement remediation for subway shield tunnels and clarify the influence of circumferential straight bolts retightening,the test device was designed and the full-scale tensile test on the circumferential joint of shield tunnel segments with straight bolts was conducted based on an actual subway shield tunnel.Based on data such as segment strain-load curves and circumferential joint opening-load curves,the variation patterns of segment strain and the tensile stiffness of circumferential joint before and after retightening straight bolts were analyzed,and the enhancement effect of retightening on the longitudinal stiffness of the shield tunnel after differential settlement remediation was quantified.The results indicate that under the same tensile loading condition,different geometric configurations of the joint interface between adjacent segments result in differences in strain distribution and variations in the location of the maximum strain value.After retightening,the contact area between the segments and bolts increases,and the strain at various measurement points on the joint interface of segments shows a slight increase,while the strain trend remains essentially unchanged compared with that before retightening.When the retightening torque is set to 486.00 N·m,the tensile stiffness of the joint increases by approximately 23％after retightening,and the longitudinal stiffness of the shield tunnel increases by approximately 18.3％,indicating a significant improvement in the longitudinal stiffness of the shield tunnel due to retightening.For tunnels where differential settlement remediation has been completed,it is recommended to remove the handhole mortar and retighten the tunnel circumferential joint bolts to enhance the longitudinal stiffness of the shield tunnel.The test results can provide an experimental basis for optimizing differential settlement remediation measures.