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大量的工程现场监测结果表明,城市中强支护隧道施工过程中其周围大部分土体仍处于小应变状态,小应变情况下土体具有显著的高模量和非线性特性。土体小应变刚度特征和应力路径相关性是准确分析土与隧道相互作用的重要因素。虽然采用双刚度的硬化土模型(hardening soil model)能够基本反映应力路径的影响,但其卸载再加载模量并没有与应力-应变水平相关,不能模拟小应变情况下土体模量的高度非线性。为此,结合小应变刚度理论对硬化土模型的卸载再加载模量进行了改进,使之与应力-应变水平相关,并且考虑了土体卸载抗剪强度指标的变化以及侧向卸荷应力路径下不同的模量。通过与土体的应力路径试验结果进行对比,证明了模型的合理性。
A large number of engineering site monitoring results show that most of the surrounding soil around the medium-sized strong support tunnel in city is still in a small strain state, and the soil has remarkable high modulus and nonlinear characteristics under small strain. The correlation between small-strain stiffness characteristics of soil and stress path is an important factor to accurately analyze the interaction between soil and tunnel. Although the hardening soil model with double stiffness can basically reflect the influence of stress path, its unloading and reloading modulus is not related to the stress-strain level, so it can not simulate the height of soil mass under small strain Linear. Therefore, combined with the theory of small strain stiffness, the unloading and reloading modulus of hardened soil model is improved to correlate with the stress-strain level. The change of unloading shear strength index and the lateral unloading stress path Under different modulus. By comparing with the soil stress path test results, the rationality of the model is proved.