考虑层间效应的钢纤维混凝土隧道单层衬砌#br# 受力特征模型试验研究

为探究考虑层间接触效应的钢纤维混凝土隧道单层衬砌内力分布规律，自行设计考虑层间效应的单层衬砌模型并研制竖向油压5MPa和侧向压力1.5MPa作为逐级施加的卧式加载试验台架，开展不同荷载作用下的钢纤维混凝土隧道单层衬砌受力特征模型试验。研究结果表明：不考虑层间接触特征的单层衬砌与考虑接触特征的单层衬砌在拱腰和墙角处的安全系数均为最低，最容易出现弯矩和轴力突变；考虑层间接触特征的单层衬砌最大弯矩与最大轴力均出现在拱脚处，层间接触面存在明显黏结力，结构的轴力增加和弯矩减小，内力变得均衡，结构的整体安全性高于不考虑层间接触面，相对不考虑层间效应，受力最不利的左右拱脚处的安全系数分别增加143.7%、149.4%；当竖向油压达到3MPa、侧向油压值达到0.9MPa时，仰拱周围层间接触面压力增长速度显著加快，仰拱处混凝土由线弹性转变为塑性，竖向油压达到4MPa，侧向油压值达到1.2MPa时，仰拱、拱角与拱顶层间接触面应力值有减小或反向增长的趋势，仰拱、墙角等界面发生破坏；钢纤维在单层衬砌裂缝扩展在30%~70%之间阻裂效果最好。

Experimental study on mechanical behavior of single-layer lining of steel fiber reinforced concrete tunnel considering interlayer effect

 In order to investigate the influence of interlayer contact on the internal force distribution of single-layer lining of steel fiber reinforced concrete tunnel, a single-layer lining model is designed, a horizontal loading test bench with the vertical oil pressure of 5MPa and the lateral pressure of 1.5MPa is developed, and the mechanical characteristic model test of single-layer lining of steel fiber reinforced concrete tunnel under different loads is carried out. The results show that both the single-layer linings with and without considering the contact characteristics between the two sides of the arch and the corner have the lowest safety factors, and the sudden changes in bending moment and the axial force are most likely to occur; For the case of the single-layer lining with the contact characteristics of interlayer considered, the maximum bending moment and axial force occur at the arch foot, obvious adhesion exists at the contact surface of interlayer, the axial force increases and bending moment of structure decreases, the internal force becomes balanced, and the overall safety of structure is higher than that without considering the contact surface; compared to the case without considering the interlayer effect, the safety factors at the most dangerous left and right arch feet were increased by 143.7% and 149.4%, respectively; When the vertical oil pressure reaches 3MPa and the lateral oil pressure reaches 0.9MPa, the interlayer contact pressure for the inverted arch increases significantly faster, and the concrete of the inverted arch changes from linear elastic state to plastic state; when the vertical oil pressure reaches 4MPa and the lateral oil pressure reaches 1.2MPa, the contact stress of inverted arch, arch foot and vault tends to be smaller or to increase reversely, so that the interfaces at the inverted arch and wall corner fail; steel fiber in single-layer lining with crack propagation between 30%~70% has the best crack resistant effect.