地铁盾构管片用钢纤维混凝土性能特征研究

Performance Characteristics of Steel Fiber Reinforced Concrete for Shield Segments Used in Subway Tunnel

盾构施工使我国隧道建设得到迅猛发展,目前盾构隧道支护主要采用的是钢筋混凝土管片,其在运输及施工等过程中易发生破损或开裂。改善混凝土的性能是控制管片质量的关键措施之一,纤维是一类有望对混凝土进行有效增强、增韧的材料。基于此,该研究将钢纤维引入到混凝土体系中,重点分析了拟用于预制地铁盾构管片的钢纤维混凝土性能特征,主要包括流动性、抗压强度和抗拉强度。结果表明,钢纤维对混凝土的流动性影响明显,为使混凝土具有较好的流动性,混凝土中钢纤维的体积掺量定为2%。在2%钢纤维掺量下,相比普通混凝土,钢纤维混凝土的28 d抗压强度和抗拉强度分别提高了27%和38%。因此,钢纤维混凝土可有效弥补传统钢筋混凝土管片存在的不足。

The shield construction technique has promoted the rapid development of tunnel construction in China.The shield tunnel supporting mainly depends on the use of reinforced concrete segment.The transportation and construction process of reinforced concrete segment may result in damage or cracking.Improving the performance of concrete is one of the key measures to control the quality of segment.Fiber is one of the materials that can effectively strengthen and toughen the concrete.Based on it,steel fiber was introduced into concrete system in this research,and the liquidity,compressive strength and tensile strength of steel fiber reinforced concrete were fully investigated.Results showed that,the liquidity of concrete was obviously influenced by steel fiber.The volume content of steel fiber was determined to be 2%of mixture when designing concrete in order to make the concrete has good liquidity.Compared with ordinary concrete,the compressive strength and tensile strength of steel fiber reinforced concrete after curing 28 d were 27%and 38%larger,respectively.Therefore,the steel fiber can effectively make up for the shortfall of traditional reinforced concrete subway shield segment.