海水侵蚀作用下盾构隧道管片劣化特征研究  

Research on the Deterioration Characteristics of Shield Tunnel Segments under the Action of Seawater Erosion

作　　者：徐冲[1] 郭佳奇[2] 徐亚峰 林晋海[1] 薛丹丹 赵秋林[1] XU Cheng;GUO Jiaqi;XU Yafeng;LIN Jinhai;XUE Dandan;ZHAO Qiulin(China Railway First Survey and Design Institute Group Co.Ltd,Xi'an,Shaanxi 710043,China;Henan Polytechnic University,Jiaozuo,Henan 454000,China)

机构地区：[1]中铁第一勘察设计院集团有限公司,西安710043 [2]河南理工大学,焦作454000

出　　处：《铁道工程学报》2021年第6期58-63,共6页Journal of Railway Engineering Society

基　　金：陕西省重点科技创新团队计划项目(2015KCT-01);中铁一院软件开发项目(17-22)。

摘　　要：研究目的:为揭示在海水荷载与离子侵蚀加持作用下盾构管片混凝土强度损失和钢筋锈胀的劣化特征演化规律,基于能量耗散理论和扩展有限元方法(XFEM)分析研究管片混凝土分别在无水土荷载和有水土荷载作用下,管片裂缝随服役时间的发育过程。研究结论:(1)侵蚀后的混凝土在海水压力作用下裂纹萌生、和塑性变形加剧,其峰值强度和弹性模量分别降低至未侵蚀混凝土的57.3%和53.9%;(2)在氯离子侵蚀作用下,管片外层混凝土锈胀裂纹具有早开裂、传播慢、后贯通的特点;而管片内层混凝土无氯离子侵蚀,锈胀裂纹具有晚开裂、传播快、先贯通的特点;(3)海水压力与侵蚀耦合作用下,钢筋孔裂纹扩展方向将垂直于最大主应力方向,管片受压区的裂纹扩展速率降低,受拉区的裂纹扩展速率提高;(4)本研究成果对揭示盾构隧道管片性能劣化机制,以及服役性能评价和维修具有一定的参考价值。Research purposes: To reveal the evolution of the deterioration characteristics of the concrete segment under the condition of concrete strength loss and reinforcement rusting and swelling under the influence of seawater loading and ion erosion, the development process of cracks with service time was analyzed based on energy dissipation theory and extended finite element method(XFEM) numerical simulation for concrete segment without and with soil and water loading.Research conclusions:(1)The crack initiation, diffusion and plastic deformation of eroded concrete under seawater pressure increased, and its peak strength and elastic modulus decreased to 57.3% and 53.9% respectively.(2)Under the action of chloride ion erosion, the rust expansion crack of outer layer concrete has the characteristics of early cracking, slow propagation and backward penetration. In contrast, the inner layer concrete without chloride ion erosion has the characteristics of late cracking, fast propagation and first penetration.(3)Under the coupling of seawater pressure and erosion, the crack growth direction of steel bar hole will be perpendicular to the maximum principal stress direction, the crack growth rate in the compression zone of the segment will decrease, and the crack growth rate in the tensile zone will increase.(4)This research result has certain reference value for revealing the deterioration mechanism of underwater shield tunnel segment and their service performance evaluation and repair.

关 键 词：混凝土管片 强度损失 离子侵蚀 锈胀开裂 

分 类 号：U451.5[建筑科学—桥梁与隧道工程]