Abstract The large horizontal deformation of lining rings caused by adjacent unloading has a serious impact on the security and normal operation of a tunnel structure, so an efficient and highly accurate method must be developed to simulate the whole process from unloading to failure. A numerical simulation of the internal force and deformation of the lining ring for different joint stiffnesses indicates that joint stiffness has little effect on the axial force distribution and magnitude of the lining ring, so the axial force of the segment joint is calculated using the equivalent stiffness ring method, which is used to determine the bending stiffness curve of the bend-resistant spring. A fine analysis is performed using the three-dimensional straight beam solid element method and a bending stiffness model for the segment joint under different axial forces is obtained. Parameters for the bending-stiffness model are used as the pa? rameters for the spring of the two-dimensional beam-spring model, and the internal force and deformation of the lining structure under different load levels is calculated by the two-dimensional beam-spring method, with results that are consistent with those of the experiment. A whole-process numerical analysis shows that the bending moment increases and the axial force decreases continuously at the joint section with the bending stiffness of the joints during the unloading process, with the bending stiffness at the joint decreasing rapidly and the structure reaching a state of failure.
Abstract：
The large horizontal deformation of lining rings caused by adjacent unloading has a serious impact on the security and normal operation of a tunnel structure, so an efficient and highly accurate method must be developed to simulate the whole process from unloading to failure. A numerical simulation of the internal force and deformation of the lining ring for different joint stiffnesses indicates that joint stiffness has little effect on the axial force distribution and magnitude of the lining ring, so the axial force of the segment joint is calculated using the equivalent stiffness ring method, which is used to determine the bending stiffness curve of the bend-resistant spring. A fine analysis is performed using the three-dimensional straight beam solid element method and a bending stiffness model for the segment joint under different axial forces is obtained. Parameters for the bending-stiffness model are used as the pa? rameters for the spring of the two-dimensional beam-spring model, and the internal force and deformation of the lining structure under different load levels is calculated by the two-dimensional beam-spring method, with results that are consistent with those of the experiment. A whole-process numerical analysis shows that the bending moment increases and the axial force decreases continuously at the joint section with the bending stiffness of the joints during the unloading process, with the bending stiffness at the joint decreasing rapidly and the structure reaching a state of failure.
.Numerical Simulation of the Bearing Capacity of a Shield Tunnel Structure in Unloading Conditions[J] MODERN TUNNELLING TECHNOLOGY, 2017,V54(6): 143-180
2017, Vol. 54 