This work analyses the effect of the change in the initial stiffness on the behaviour of two geotechnical structures performed on/in overconsolidated clays: an embankment built on Boston blue clay and a tunnel dug in London clay. The numerical predictions are performed with the MIT-E3 model, which reproduces the small strain nonlinearity and hysteretic stress–strain response observed in unload-reload cycles. Firstly, the performance of the constitutive model to replicate an unload-reload cycle of a consolidation test is validated. The initial stiffness is varied by changing the κ_o parameter of the MIT-E3 model. Thus, several numerical predictions of the two geotechnical structures, performed for different κ_o values are compared with each other and field measurements, in terms of settlement and horizontal displacements. The results show that the variation in initial stiffness has a greater effect on the behaviour of the tunnel than the embankment. In fact, in the case of the tunnel, the majority of the stress paths occur inside the yield surface, where the stiffness is the key parameter. On the other hand, for the embankment, the yield occurs in the major part of the domain, therefore the stiffness effect is less significant.

这项工作分析了初始刚度变化对在超固结黏土上/内部进行的两个岩土结构行为的影响：建在波士顿蓝色黏土上的路堤和在伦敦黏土上挖出的隧道。数值预测是使用MIT-E3模型执行的，该模型再现了在卸载-再加载循环中观察到的小应变非线性和滞后应力-应变响应。首先，验证了本构模型复制固结测试的卸载-重新加载循环的性能。初始刚度是通过改变κ变化_Ô该MIT-E3模型的参数。因此，两个岩土结构的若干数字预测，对于不同的κ进行_ö分别比较沉降值和水平位移的实地测量值。结果表明，初始刚度的变化比路堤对隧道的行为影响更大。实际上，在隧道的情况下，大部分应力路径都发生在屈服面内部，其中刚度是关键参数。另一方面，对于路堤，屈服发生在区域的主要部分，因此刚度效应不太明显。