A novel semi-analytical solution to ground reactions of deeply buried tunnels considering the nonlinear behavior of rocks
A novel semi-analytical solution to ground reactions of deeply buried tunnels considering the nonlinear behavior of rocks
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DOI：
10.1016/j.compgeo.2023.105429
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发表时间：
2023-07
影响因子：
5.3
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中科院分区：
文献类型：
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随着隧道埋深的增加，围岩的非线性变得更加显著，从而改变了隧道开挖过程中的应力重分布和变形模式。在这项研究中，一个新提出的UHS模型（统一的应变硬化和应变软化本构模型）和有限差分法，以获得一个新的半解析解，用于调查的非线性特性，如应变硬化和应变软化对地面反应的影响。计算节点的屈服面与塑性内变量一致，并通过迭代求解。解微分方程是不必要的。因此，建议的解决方案可以用来准确地计算塑性内变量和塑性区的应力状态，而不会出现以前的解决方案中经常观察到的应变硬化区的应力振动。通过与经典解和数值结果的比较，验证了所提出模型的有效性。然后，应变硬化，应变软化，和预应力对地基反力的影响突出。随着峰后延性的增大，塑性区半径和洞壁位移逐渐减小。考虑应变硬化特性会增大塑性区半径。此外，预应力显着降低塑性区半径和隧道壁位移深埋隧道。
The nonlinearity of rock becomes more significant as the buried depth increases, which changes the stress redistribution and deformation patterns during tunneling. In this study, a newly proposed UHS model (unified strain-hardening and strain-softening constitutive model) and the finite difference method are applied to obtain a novel semi-analytic solution that is used to investigate the effects of nonlinear characteristics such as strain-hardening and strain-softening on the ground reaction. The yield surface and the plastic internal variable of the calculated node are consistent and are solved by iteration. The solution of differential equations is unnecessary. Therefore, the proposed solution can be used to accurately calculate the plastic internal variable and the stress state in the plastic zone without stress vibration in the strain-hardening zone that was often observed in previous solutions. The proposed model is validated via comparison to the classical solution and numerical results. Then, the influences of strain-hardening, strain-softening, and prestress on ground reactions are highlighted. The radius of the plastic zone and the displacement of the tunnel wall gradually decrease with increasing post-peak ductility. Considering strain-hardening characteristics would increase the radius of the plastic zone. Moreover, prestressing significantly reduces the plastic zone radius and tunnel wall displacement in deeply buried tunnels.