摘要
采用1∶1带预制裂缝的隧道衬砌试件开展套拱加固衬砌荷载结构试验,原衬砌预制裂缝深度分别为衬砌厚度的1/3和2/3,原结构和新增套拱之间充分粘结,试验得到叠合式套拱加固带裂缝衬砌的变形破坏规律和影响因素。叠合套拱加固试件受弯过程为"加载—套拱开裂—叠合面产生裂缝—破坏",共3个阶段。叠合面裂缝的出现将使衬砌刚度急剧降低,预制裂缝高度为1/3衬砌厚度的试件,其开裂弯矩、短期刚度和受弯承载力比按照完整钢筋混凝土梁计算的短期刚度减少3.19%、23.58%,19.35%,预制裂缝为竖向扩展,破坏模式为延性破坏;预制裂缝高度为2/3衬砌厚度的试件,其开裂弯矩、短期刚度和受弯承载力比理论值减少14.39%、54.37%、37.78%,预制裂缝为斜向扩展,破坏模式为脆性破坏。根据试验结果提出叠合式套拱的开裂弯矩、短期刚度和受弯承载力计算方法。
Loading tests on two 1：1 tunnel lining specimens reinforced by umbrella arch with 1/3 and 2/3 crack depth/ lining thickness ratios were conducted. The specimens were tested to obtain the cracking patterns within the arch reinforcement area and the causes of such damages. The deformation of the specimens reinforced by stacked umbrella arch can be separated into three stages, namely, load-specimen crack stage, ＂specimen crack-adjoining plane crack＂ and ＂adjoining plane crack-specimen fail＂. Occurrence of adjoining plane crack may significantly decrease the lining stiffness. Specimen with prefabricated 1/3 crack depth/lining thickness ratio was 3.19% , 23.58%, 19.35% less than damaged member in bending moment of cracking, short-term stiffness and bending bearing capacity, respectively. While the specimen with prefabricated 2/3 crack depth/lining thickness ratio was 14.39% , 54.37% and 37.78% less than the theoretical value, respectively, and it was observed that prefabricated crack extended diagonally in fragile failure mode. Finally, based on test results, computational methods are proposed for the cracking-moment, short-term stiffness and bending capacity of stacked umbrella arch.
出处
《土木工程学报》
EI
CSCD
北大核心
2013年第10期127-134,共8页
China Civil Engineering Journal
关键词
叠合式套拱
隧道加固
承载力计算
足尺试验
衬砌裂缝
stacked umbrella arch
tunnel reinforcement
bearing capacity calculation
full-scale test
lining crack
