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隧道衬砌发生的局部破坏主要由轴向压力和弯矩控制,因此其承载能力极限状态设计重点在于结构在偏心受压作用下的验算。为了研究钢纤维混凝土(SFRC)应用于隧道衬砌时的受力特征,确定承载能力极限状态时的衬砌断面应力分布,参考国内外相关试验标准和分析方法,对32个钢纤维混凝土压弯梁进行了韧性试验,并得到了32个试件的荷载-张口位移(CMOD)曲线。通过分析试验结果,确定了特定水泥基体、钢纤维类型和掺量等情况下钢纤维混凝土应力-应变本构关系简化模型中受拉区强度指标,并提出了在考虑轴力及附加偏心时,与梁高有关的尺寸效应经验公式。
The local damage of tunnel lining is mainly controlled by the axial pressure and bending moment. Therefore, the ultimate design of bearing capacity of the tunnel lining lies in the checking of the structure under the eccentric compression. In order to study the stress characteristics of steel fiber reinforced concrete (SFRC) used in tunnel lining and to determine the stress distribution of lining section under ultimate load carrying capacity, reference is made to relevant test standards and analytical methods both at home and abroad. 32 steel fiber reinforced concrete bending beams The ductility test was carried out and the load-mouth displacement (CMOD) curve of 32 specimens was obtained. By analyzing the test results, the strength index of tension zone in the simplified model of stress-strain constitutive relationship of steel fiber reinforced concrete under certain cement matrix, steel fiber type and dosage is determined. When axial force and additional eccentricity are considered, The empirical formula of size effect related to beam height.