Abstract Tunnel excavation in squeezing ground is very challenging due to the difficulty in making reliable predictions at the preliminary design stage. Tunnel response in squeezing ground is made possible by employing creep constitutive models. However, literature outlines the limitations of the conventional creep constitutive models in estimating delayed deformations due to the squeezing mechanism. Hence this paper presents, a fractional-order derivative viscoelastic viscoplastic (FDVP) constitutive model capable of estimating delayed deformations characterized by squeezing. The FDVP constitutive equations are derived as an extension to the Burgers model and adjusted Perzyna overstress function with an associated viscoplastic flow rule. The constitutive model validation and verification are conducted by using the experimental data obtained from literature and monitored tunnel convergence data, respectively. Thereafter, the constitutive equations are implemented in FLAC3D and applied to simulate deformations responsible for squeezing within a tunnel employing in-built constitutive models for verification purposes. The constitutive model shows very good agreement with experimental data and yields close results with monitored tunnel convergence data. The model can be successfully used in numerical code for tunnel stability analysis in squeezing ground.

中文翻译：

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考虑超应力理论的蠕变本构模型与关联粘塑性流动规则

摘要 由于在初步设计阶段难以做出可靠的预测，挤压地层的隧道开挖非常具有挑战性。通过采用蠕变本构模型，使挤压地层中的隧道响应成为可能。然而，文献概述了传统蠕变本构模型在估计由于挤压机制引起的延迟变形方面的局限性。因此，本文提出了一种分数阶导数粘弹性粘塑性 (FDVP) 本构模型，该模型能够估计以挤压为特征的延迟变形。FDVP 本构方程是作为 Burgers 模型的扩展导出的，并使用相关的粘塑性流动规则调整 Perzyna 过应力函数。本构模型的验证和验证分别使用从文献中获得的实验数据和监测的隧道收敛数据进行。此后，本构方程在 FLAC3D 中实现，并应用于模拟隧道内的挤压变形，采用内置本构模型进行验证。本构模型与实验数据显示出非常好的一致性，并与监测的隧道收敛数据产生了接近的结果。该模型可成功用于挤压地层隧道稳定性分析的数值编码。本构方程在 FLAC3D 中实现，并应用于模拟隧道内的挤压变形，采用内置本构模型进行验证。本构模型与实验数据显示出非常好的一致性，并与监测的隧道收敛数据产生了接近的结果。该模型可成功用于挤压地层隧道稳定性分析的数值编码。本构方程在 FLAC3D 中实现，并应用于模拟隧道内的挤压变形，采用内置本构模型进行验证。本构模型与实验数据显示出非常好的一致性，并与监测的隧道收敛数据产生了接近的结果。该模型可成功用于挤压地层隧道稳定性分析的数值编码。