摘   要：为了客观评价自然干燥状态使用环境下单层衬砌湿喷混凝土的抗弯性能，参考ASTM C1609，采用0.05mm/min的加载速率对在温度（20±2）℃、相对湿度（60±5）%的条件下分别放置0、16h、24h及72h三种湿喷混凝土试件进行了抗弯性能试验。结果表明，自然干燥条件下钢纤维较粗合成纤维更容易散失混凝土中的水分；湿喷混凝土的抗弯强度随含水率的降低近乎呈线性递减，且含水率降低2.0%～2.4%和3.1%～3.9%，抗弯强度分别降低了25%～40%和38%～50%。干燥初期（16～24h）0.5mm、1.0mm和2.0mm挠度处的残余抗弯强度和2.0mm挠度处的抗弯断裂能分别降低了5%～39%和10%～32%。

Abstract: For the objective evaluation of flexural behavior of wet shotcrete(WSC) used in single shell lining under natural drying conditions, the flexural behavior of the specimens located in the environment of (20±2)℃ and (60±5)% relative humidity for 0, 16, 24 and 72 hours were tested at a loading rate of 0.05mm/min referring to ASTM C1609. The results indicate that, under natural drying conditions, steel fiber reinforced WSC is easier to dissipate moisture than that of synthetic macro-fiber; flexural strength of WSC almost linearly decreased with lowering of the moisture content of concrete, and the moisture content is reduced by 2.0% to 2.4% and 3.1% to 3.9%, the flexural strength is respectively decreased by 25% to 40% and 38% to 50%. During initial drying period (16～24h), the residual flexural strength of WSC at 0.5mm, 1.0mm and 2.0mm deflection and flexural fracture energy at 2.0mm deflection are respectively decreased by 5% to 39% and 10% to 32%.