盾构法施工荷载对小半径曲线隧道管片防水性能的影响研究

Influence of Shield Tunneling Construction Load on Waterproofing Performance of Small Radius Curved Tunnel Segments

为探究小半径曲线盾构隧道施工过程中施工荷载对管片防水性能的影响,依托深圳国际会展中心配套市政项目盾构段,选取油缸推力和螺栓预紧力作为主要施工荷载,采用ANSYS建立管片结构模型和弹性密封垫模型,对施工荷载下管片的张开量以及相应张开量下的管片防水性能进行研究,得到施工荷载对管片防水性能的影响。研究结果表明:1)油缸推力对环缝影响较大,会加大环缝张开量,但对纵缝影响较小;2)管片间弹性密封垫的防水性能随管片张开量的增加先增大后减小,在张开量为2mm以及大于6mm时存在渗水风险;3)以张开量2mm为计算控制标准,油缸推力使直线段管片防水性能下降8%,曲线段下降15%;4)增大螺栓预紧力能略微提高直线段管片的防水性能,但对曲线段管片的防水性能无影响,曲线段整体防水性能较差。

The cylinder thrust force and bolt pre-tightening force are selected as the main research construction loads, the structure model and rubber seal model are established by ANSYS, and the segment opening amount under construction load and the waterproofing performance under the corresponding segment opening amount are studied by taking the shield section of municipal project of Shenzhen Metro International Exhibition Center for example. The relationship between construction load and waterproofing performance of segment is obtained. The research shows that:(1) The cylinder thrust force has great influence on the circumferential joint and little influence on the longitudinal joint and it will increase the opening amount of circumferential joint.(2) The waterproof performance of rubber seal gasket between segments increases first, and then decreases with the increase of segment opening amount;the risk of seepage exists when the opening amount is 2 mm or more than 6 mm.(3) By taking 2 mm opening amount as calculation control standard, the cylinder thrust force reduces the waterproofing performance of the segment in the straight line section by 8% and the curved section by 15%.(4) The increase of the pre-tightening force of the bolt can slightly improve the waterproofing performance of the segment in the straight line section, but has no effect on the waterproof performance of the segment in the curved section. The waterproofing performance of segments in curved section is worse than that in straight under the same construction form.