【作者】 李华明；

【导师】 潘绍伟；

【作者基本信息】 西南交通大学 ， 桥梁与隧道工程， 2005， 硕士

【摘要】 近年来,混凝土的裂缝问题在工程实践中越来越突出,尤其是在隧道工程中更是如此,对结构的安全性、耐久性提出了考验。 隧道混凝土衬砌开裂是发生几率较多的隧道病害之一,如何从根本上解决该问题是广大隧道工程技术人员非常关心的项目。采用聚丙烯纤维混凝土作为隧道混凝土衬砌来解决混凝土开裂的问题是近年来广泛研究和应用的一种新的途径。其原理主要在于,混凝土中水泥作为胶凝材料来握裹纤维,这些纤维起到微细配筋作用,消耗混凝土变形开裂能量、提高韧性、撑托骨料和减少混凝土离析泌水,从而控制水泥基体内部微细裂缝的生成和扩展,提高混凝土的抗裂性能。 本文介绍了纤维混凝土增强机理的两种理论,即复合材料理论和纤维间距理论,推导出了复合材料的抗拉初裂强度公式和极限强度公式。同时,通过对纤维混凝土和普通混凝土在工作性能、抗压、抗拉、弹性模量、干缩、抗裂、耐久性、韧性及抗高温性能等方面的对比试验研究,对纤维混凝土的性能进行了综合分析,得出了纤维混凝土在物理力学性能上的优势。 另外,本文还结合实际工程项目,进行了现场喷射纤维混凝土试验,也证明了纤维混凝土能有效提高喷射混凝土的强度稳定性,降低回弹率,明显改善施工条件,提高工程质量,延长结构使用寿命。更多还原

【Abstract】 In recent years,the crack problem of the concrete is more and more outstanding in engineering practice and also such in the tunnel engineering particularly,it puts forward the test to the safety and durability of the structure.The tunnel concrete lining cracking is one of several tunnel diseases to take place with more rate,how to resolve that problem by the root is the special regardful item for the large number of technical personnel of the tunnel engineering.That adopting the polypropylene fiber concrete to be the tunnel concrete lining and resolving the problem of the concrete appearing crack is a kind of new extensively studies and applications path in recent years. Its principle mainly lies in: the cement in the concrete is the gelatinization material to bone to the fibers, These fibers are similar to very small distributed reinforcing steel bar in function, consuming the energy of the concrete cracking,raising the concrete toughness,bracketing aggregates and reducing the concrete segregation and bleeding,thus they control the generation and expansion of the internal microscopic checks of the cement,and raise the concrete crack resitance.This thesis introduces two kinds of the fiber-reinforced concrete mechanism, namely the composite material theories and the fiber-spacing interval theories, and deduces the formula of the first-crack strength of extension and the ultimate strength of extension of the composite materical.At the same time, through these check experiments between the fiber concrete and the common concrete,such as working performance,compression strength,strength of extension,elastic radio,dry shrink-age,crack resistance,durability,toughness and high temperate endurance, the paper analyzes synthetically the performance of the fiber concrete,and gets the knowledges of the predominance of the fiber concrete on the physical and mechanical properties.Moreover,according to the actual engineering item,we still make the experiments of the sprayed fiber concrete on the spot, also prove that the fiber concrete can raise the strength stability of sprayed concrete, reduce its rebound elasticity, improve obviously the construction conditions, raise the construction quantity, prolong the service life of structure.更多还原