The design load of a loessal tunnel is usually calculated using the conventional Mohr-Coulomb strength criterion, which ignores the structural strength of loess and provides inaccurate calculation results. The present paper therefore proposes a bilinear strength criterion considering the structural strength characteristics of loess determined in a triaxial shear experiment. Then, using the new strength criterion, a new theoretical solution is derived for the stress and displacement of loess in each region separately; the solution is validated by numerical simulation. Lastly, the ground reaction curve and the design load of a tunnel are obtained using the proposed method considering the structural strength of loess. The results obtained using the new method are more reasonable and accurate than the results calculated using the conventional method. The proposed strength criterion and theoretical solution expand the knowledge base of loess engineering and provide guidelines for the design and construction of underground structures in loess ground.

黄土隧道的设计荷载通常是使用常规的Mohr-Coulomb强度准则计算的，该准则忽略了黄土的结构强度并提供了不准确的计算结果。因此，考虑到在三轴剪切试验中确定的黄土的结构强度特征，本文提出了一种双线性强度准则。然后，使用新的强度准则，分别为每个区域的黄土应力和位移推导了新的理论解。通过数值模拟验证了该解决方案。最后，考虑了黄土的结构强度，利用所提出的方法获得了隧道的地基反应曲线和设计荷载。与使用传统方法计算的结果相比，使用新方法获得的结果更加合理和准确。