钢纤维混凝土背管结构模型试验研究

结合三峡电站厂房背管结构的优化设计,对背管结构进行模型试验研究。在进行材料试验的基础上，分别进行了常规混凝土、钢纤维混凝土和少筋混凝土试验，重点研究了背管结构的初裂荷载、极限荷载、混凝土应变、钢筋和钢衬应力，比较了背管结构采用钢纤维混凝土与常规混凝土的特性，分析了钢纤维混凝土与钢筋相互作用机理。试验结果表明：在同等条件下，采用钢纤维混凝土可以明显提高混凝土结构的抗裂能力，但混凝土结构的限裂作用仍然主要依靠钢筋，两者结合使背管结构工作特性更好。

Model test of steel fiber concrete in back tube structure

Structural model tests of back tube were performed to optimize the design of back tube of powerhouse of the Three Gorges Project. On the basis of model material tests, steel fiber concrete, conventional concrete and lack bar concrete tests were respectively conducted. Studying key points were initial loads, limit loads, concrete strains, and stresses of reinforcement bar and steel lining. The characteristics of back tube structures made of fiber concrete and conventional concrete are compared. Interaction between fiber concrete and reinforcement bar are analyzed. The results of test indicate that under same condition employing steel fiber concrete can obviously increase capacity of resistance crack, but capacity of limiting crack of concrete structure still mainly depends on reinforcement bar. Coalescence of both steal fiber and bar in concrete can obtain better structure performances.