摘要
为探明盾构隧道管片衬砌的局部破坏特性,定量评价结构的安全状态,选取考虑前后环错缝拼装组合的原型管片结构局部构件进行加载试验研究。详述结构裂缝的发展、主应力的分布、螺栓的受力与管片内力、变形以及接缝张开、错台的关系,揭示结构的破坏机理,并采用数值计算对试验结果进行验证。研究结果表明:结构初始裂缝出现在中间环内弧面靠近相邻环接缝处,并发展成为最终破坏的主裂缝。在恒定截面轴压比、增大偏心距的加载方式下,结构中部为压弯破坏,两侧为压剪破坏。试件接缝并未发生破坏,张开量较小,错台量较大,手孔附近应力集中较为严重。错缝构件的破坏机理可归纳为:结构刚度较大的区域首先开裂,导致整体刚度重分布,之后刚度较大的区域继续开裂,如此循环,直至结构变形过大发生破坏。可将裂缝宽度、接缝错台量与控制截面竖向位移作为结构安全的评价指标。
In order to investigate the local failure characteristics of segmental lining for shield tunnel and quantitatively evaluate the safety state of the structure,a local prototype test was carried out on a staggered assembled segmental lining.The relationships between crack development,stress distribution and bolt internal force to structural internal force and deformation,joint opening and dislocation were described in detail.The failure mechanism of the structure was thus analyzed and the test results were verified by the numerical calculated ones.The results show that the initial crack in the structure appears at the middle ring close to the longitudinal joint of the adjacent ring,and develops into the main crack at final damage.The compression-flexure failure occurs in the middle of the structure and the compressive shear failure occurs at both ends of the structure when the axial compression ratio of control section remains constant and bending moment increases.There is no damage to the joints,the joint opening is smaller but the dislocation is larger.The stress concentrations near the hand hole are serious.The failure mechanism is found to be caused by cracking in the region where the stiffness is relatively larger.In addition,the cracking results in the redistribution of the overall stiffness of the structure,and subsequently the region with the greatest stiffness continues to crack,repeating the cycle until the structure is damaged with excessive deformation.Moreover,the crack width,joint dislocation and vertical displacement of control section can be taken as the evaluation indexes of structural safety.
作者
邱月
封坤
何川
苏昂
梁坤
Qiu Yue;Feng Kun;He Chuan;Su Ang;Liang Kun(Key Laboratory of Transportation Tunnel Engineering of the Ministry of Education,Southwest Jiaotong University,Chengdu 610031,China;China-Japan RSC Structure Research Center,Southwest Jiaotong University,Chengdu 610031,China)
出处
《土木工程学报》
EI
CSCD
北大核心
2019年第4期98-108,共11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)
中国铁路总公司科技开发计划重点课题(2014G004-0)
关键词
盾构隧道
局部原型试验
破坏特征
破坏机理
错缝拼装
shield tunnel
local prototype test
failure characteristic
failure mechanism
staggered assembling
