基于全盾壳模型的类矩形盾尾力学性能数值模拟研究OA北大核心

Shield shell is an important barrier to protect the safety of personnel and equipment inside the shield machine.As the area for segment assembly in the shield shell structure,the shield tail cannot be equipped with large baffles,ribs and other reinforcement measures,making it the weakest position of the shield shell.Besides,the stress performance of the quasi-rectangular shield tail is significantly different from the traditional circular shield tail.In order to truly reflect the stress performance of the quasi-rectangular shield tail,verify the safety of the quasi-rectangular shield tail under various construction loads,and guide subsequent optimization design,a full shield shell model including front shell 1,front shell 2,rear shell,and shield tail was established using finite element software.In the model,the influence of the load of the shield tail brush and the shield tail grease cavity was taken into consideration,and a simulation study was conducted on the mechanical performance of the shield tail under straight tunneling conditions.The results are drawn as follows.The maximum deformation and stress of the quasi-rectangular shield tail in the background project are both located at the vault of the free end of the shield tail.Under the straight tunneling condition at a depth of 18 m,the maximum stress was 48.58 MPa,the maximum horizontal deformation is 5.88 mm,and the maximum vertical deformation is 16.66 mm,indicating sufficient stiffness and strength reserves to meet construction safety requirements.Compared to the calculation model that only considers the shield tail,the full shield shell calculation model can provide results closer to the actual engineering measurement data.Therefore,it can be considered that the full shield shell model can more accurately reflect the mechanical properties of the shield tail.The load of the shield tail grease cavity significantly affects the calculation results of the deformation and stress of the shield tail.The influence of this load should be considered in the study of the mechanical properties of the shield tail.However,due to its low stiffness,the shield tail brush has no significant effect on the overall mechanical performance of the shield tail.Through parameter analysis,the influence of formation properties,burial depth,and shield tail thickness on the mechanical properties of the shield tail is clarified,while the thrust force has little effect on the mechanical properties of the shield tail.