海相地层地铁盾构隧道钢筋钢纤维混凝土管片可靠度研究

Study on Reliability of Steel Fiber Reinforced Concrete Segments of Metro in Marine Strata

地铁盾构隧道管片材料的选取决定了管片性能与结构的整体安全度与可靠度,钢纤维混凝土材料在抗裂、抗震、抗疲劳、抗冲击等方面具有比普通混凝土更好的力学特性。为此,文章针对深圳地区海相地层地铁盾构隧道管片衬砌,基于可靠度理论,在混凝土材料中加入钢纤维,优化配合比设计,并通过系列试验开展了钢筋钢纤维混凝土管片可靠度研究。结果表明:(1)在盾构隧道不出现大变形的前提下,以少配筋加钢纤维混凝土管片为最佳选择方案;(2)在配筋率相同时,少筋加钢纤维混凝土管片比原配筋混凝土管片具有更高的可靠度,且受钢纤维的掺量、品种、形状和长径比等因素综合影响;(3)钢筋钢纤维混凝土管片能极大提高盾构隧道管片衬砌结构的可靠度指标,满足海相地层地铁隧道结构耐久性的安全标准。

The selection of segment materials determines the segment performance and the overall safety and reli⁃ability of the structure.Steel fiber reinforced concrete materials have better mechanical properties than that of nor⁃mal concrete in terms of crack resistance,earthquake resistance,fatigue resistance and impact resistance.Therefore,based on the reliability theory,steel fiber is added into the concrete material to optimize the mix design,and a series of tests are carried out to study the reliability of steel fiber reinforced concrete segment aiming at the segment lining of the Shenzhen shield tunnel in marine strata.The results show that:(1)in the case without large deformation,the best scheme is to use steel fiber reinforced concrete segments with less reinforcement;(2)under the same reinforce⁃ment ratio,the steel fiber concrete segment with less reinforcement has higher reliability than that of the original steel reinforced concrete segment,and it is affected by amounts of steel fiber admixture,varieties,shapes and aspect ratios;(3)steel fiber reinforced concrete segment can greatly improve the reliability of lining structure and meet the safety standard of metro tunnel structure durability in marine strata.