隧道聚丙烯纤维混凝土抗渗性能分析及试验比较

作为一种新型隧道防水衬砌材料，聚丙烯纤维混凝土的抗渗研究大多还仅局限于抗渗机理的定性解释上。为进一步揭示其抗渗性能，结合断裂力学原理和细观结构的力学分析，推导出了混凝土内部裂纹处的纤维闭合力及其应力强度因子，提出了纤维对张开型裂纹扩展的阻碍效应解析式，并在此基础上，通过数值计算，对聚丙烯纤维混凝土的抗渗性能给出了合理解释；另一方面，为将其与传统的微膨胀混凝土的抗渗性能进行比较，开展了4组不同类型混凝土的抗渗性能试验，通过比较发现，工程中常用掺量的聚丙烯纤维混凝土的抗渗性能优于微膨胀混凝土，而合理双掺（聚丙烯纤维和微膨胀剂）可使混凝土的抗渗性能达到最佳。

Analysis of Impervious Performance about Tunnel Polypropylene Fiber Concrete and the Experimental Comparison

Recently, most impermeability seudies of polypropylene fiber concrete, as a new sort of tunnel lining waterproof material, are limited to the impervious mechanism and unable to be satisfied with the engineering need. On the basis of fracture mechanics and the micro-structure mechanics, the resistance of fiber to the crack extension inside concrete and it＇s SIF were deduced, the analytical formula of fiber resistance effect to the opening mode crack extension was presented as well. Meanwhile, the impervious performance of polypropylene fiber concrete was explained reasonably by the numerical calculation of the resistance effect. On the other hand, for comparing the impervious performance of polypropylene fiber concrete with that of UEA concrete, the impervious performance experiments of four groups of different types of concrete were carried out, it is presented that the former is superior to the latter. More than that, adding double polypropylene fiber and UEA to the concrete with proper proportion will make the impervious performance much better.