隧道钢纤维喷射混凝土性能试验及其工程应用

PERFORMANCE EXAMINATION OF STEEL FIBER REINFORCED SHOTCRETE IN TUNNEL AND ITS ENGINEERING APPLICATION

根据钢纤维喷射混凝土结构力学原理,为了研究钢纤维混凝土喷层在隧道单层永久衬砌支护中适用性,先分析钢纤维在混凝土中的增强力学作用机制,然后完成钢纤维喷射混凝土合理配比、抗拉、抗压、抗折及抗折初裂强度和弯曲性能等指标的室内试验;并结合具体的隧道现场喷射试验,以及围岩应力、钢纤维混凝土喷层应力及洞周附加水平收敛等监测数据进行分析。研究结果表明,钢纤维喷混凝土抗拉、抗折强度高,韧性好,喷层中的应力分布较均匀,具有较好的让压能力,喷射作业回弹损失量减少,说明钢纤维喷射混凝土是一种理想的单层衬砌支护材料,具有较好的推广应用价值。

According to the mechanical analysis of principle of steel fiber reinforced shotcrete structure,the applicability of steel fiber reinforced shotcrete in the tunnel of single-layer permanent lining is researched.The mechanics function mechanism of steel fiber reinforced concrete is analyzed firstly,and then the reasonable proportion,tension,resistance of compression,flexural strength,first-crack strength and index of flexural toughness of steel fiber reinforced shotcrete are completed by laboratory test.Moreover,combined with the typical spraying test in tunnel engineering,the measured data of stress in wall rock,spray stress of steel fiber concrete and level convergence in tunnel are analyzed.The spotting spraying experiment in tunnel shows that the tensile strength and toughness of the steel fiber reinforced shotcrete are higher than those of general one,the stress distribution is more homogeneous,the yield capacity is better,and the rebound of the steel fiber reinforced shotcrete is reduced.The results show that steel fiber reinforced shotcrete is perfect timbering material for single-layer permanent tunnel lining and it has wider application.