摘要
长距离输气盾构隧道常需穿越复杂地层,接缝作为衬砌结构的薄弱环节,构造复杂,在大弯压荷载下变形易超出设计要求而导致破损。为探明接缝的压弯力学特性和破坏机理,选取原型弧形接缝结构进行加载试验。详述接缝影响范围内管片受力、变形、破坏的全过程,定量分析破坏程度与结构内力、形变的关联。结果表明:偏心距可影响接缝变形的挤压、隆起趋势从而影响结构的弯矩分布。在压弯作用下,接缝经历了螺栓屈服前缓慢变形阶段、屈服时突变阶段和屈服后快速变形破坏阶段。接缝破坏时变形量较小,两侧被压溃的混凝土范围约等于管片厚度。破坏机理可归纳为:螺栓屈服导致接缝张开,致使弹性密封垫下部接触受压区面积减小、压强增大造成混凝土压溃,进而外弧边沿嵌缝槽处混凝土受压接触并最终压溃,导致接缝破坏。
Long gas transmission shield tunnels often run through complex strata.Joint, as vulnerable location of segmental lining,is complex in its detail and configuration, and its deformation may easily exceed the design requirements under large bending-compression load causing the damage of segmental linings.In order to investigate the mechanical properties and failure mechanism of the joint under large bending-compression load, a series of prototype tests of the curve-shaped joint were carried out.A detailed description was given to highlight the complete mechanical behaviors, such as stress, deformation and failure, of the segmental disturbed region affected by the joint.Then the relationships between the damage degree and internal force/deformation of the structure were quantitatively analyzed.The results show that the eccentricity can lead to the extrusion or uplift of the structure, and affect the distribution of segmental bending moment along the circumferential direction.Under large bending-compression load, the failure process can be divided into three stages, namely the slow deformation stage before yielding of bolt, the sudden deformation stage due to yielding of bolt, and the rapid deformation and failure stage after yielding of bolt.When the joint is damaged, the deformation amount is small, and the range of crushed concrete on both sides of the joint is approximately equal to the thickness of the segment.The failure mechanism can be described as follows: the joint open due to the yielding of bolt, resulting in the decrease of the contact area of compressive zone under the elastic sealing gasket the increase of concrete pressure and the collapse of concrete.Subsequently, the concrete at the outer edge of the caulking groove is pressed and finally crushed, leading to the final damage of the joint.
作者
邱月
何聪
何川
封坤
胡熠
郑立宁
Qiu Yue;He Cong;He Chuan;Feng Kun;Hu Yi;Zheng Lining(China Southwest Geotechnical Investigation&Design Institude Co.,Ltd.,Chengdu 610052,China;China Railway Eryuan Engineering Group Co.,Ltd.,Chengdu 610031,China;Key Laboratory of Transportation Tunnel Engineering,Ministry of Education,Southwest Jiaotong University,Chengdu 610031,China)
出处
《土木工程学报》
EI
CSCD
北大核心
2020年第7期108-115,128,共9页
China Civil Engineering Journal
基金
国家重点研发计划课题(2016YFC0802205)
国家自然科学基金(51878569,51578462)
四川省科技计划项目(2019YFS0070)。
关键词
输气盾构隧道
管片接缝
原型试验
压弯特性
破坏机理
gas transmission shield tunnel
segmental joint
prototype test
bending-compressive behavior
failure mechanism
