Sprayed concrete linings (SCLs) used in tunnels generally develop secondary deformations over time, even in the presence of constant stress levels within the lining. These deformations influence the loading process on the lining and therefore also the stress levels within the support structure. The behaviour of a SCL in a tunnel was investigated under different operating conditions in order to evaluate the effect of secondary deformations on the evolution of stability conditions (safety margins with respect to the possible concrete failure) over time, after completion of the tunnel construction. A parametric analysis was performed to study eight different types of tunnels, with variable geometry and rock quality, and eight different types of sprayed concrete. The 64 cases of the parametric analysis covered the vast range of variability of influential parameters and yielded useful information concerning the effects of secondary deformations over time on the static behaviour of the lining and on the safety factor with reference to the possible failure of the sprayed concrete.

中文翻译：

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蠕变阶段喷射混凝土衬砌安全系数的评估

即使在衬砌内存在恒定应力水平的情况下，隧道中使用的喷涂混凝土衬砌（SCL）通常也会随时间推移产生二次变形。这些变形会影响衬砌上的加载过程，进而影响支撑结构内的应力水平。在隧道施工完成后，研究了SCL在不同操作条件下的行为，以评估二次变形对稳定性条件（关于可能发生的混凝土破坏的安全裕度）随时间演变的影响。进行了参数分析，研究了八种不同类型，具有可变几何形状和岩石质量的隧道以及八种不同类型的喷射混凝土。