Effect of rock nonlinear mechanical behavior on plastic zone around deeply buried tunnel: a numerical investigation
Effect of rock nonlinear mechanical behavior on plastic zone around deeply buried tunnel: a numerical investigation
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DOI：
10.1016/j.compgeo.2023.105532
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发表时间：
2023-09
影响因子：
5.3
通讯作者：
Y. Qiao;Ying-chao Xiao;W. Ding;M. He
中科院分区：
文献类型：
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作者：
Y. Qiao;Ying-chao Xiao;W. Ding;M. He
深埋隧道围岩表现出明显的非线性力学行为，它会影响隧道周围的应力重分布和塑性区大小。因此，进行了一系列的数值模拟，突出岩石非线性行为的影响PZ与实施一个新的建议统一的应变硬化和应变软化（UHS）本构模型。UHS模型能很好地描述应力-应变曲线、峰值强度和剩余强度的非线性。首先通过模型试验结果对数值模型进行了验证，然后对UHS模型和初始应力场的参数敏感性进行了分析。讨论了应变硬化、应变软化、岩石峰值强度和剩余强度的非线性、隧道埋深和侧压力系数等因素的影响。最后提出了考虑岩石非线性的PZ的详细描述方法。结果表明：PZ可分为残余区、应变软化区和应变硬化区;最大切向应力位于应变硬化区;初始应力状态可改变PZ的形状。另外，对于深埋隧道，预应力措施具有较好的控制PZ的潜力，应尽早进行支护，以减少初始应力的释放。
Rock shows a significant nonlinear mechanical behavior in the deeply buried tunnel, and it could affect the stress redistribution and the magnitude of the plastic zone (PZ) around the tunnel. Therefore, a series of numerical simulations were performed to highlight the effect of rock nonlinear behavior on PZ with the implementation of a novel proposed unified strain-hardening and strain-softening (UHS) constitutive model. UHS model can well describe the nonlinearity of stress–strain curves, peak strength and residual strength. The numerical model was first validated via the experimental results of one model test, followed by the parameter sensitivity of UHS model and initial stress field. The effect of strain-hardening, strain-softening, the nonlinearity of peak and residual strengths of rock, buried depth of tunnel and the lateral pressure coefficient were discussed. A detailed description method of the PZ was finally proposed considering the nonlinearity of rock. The results reveal that (i) PZ can be divided into the residual zone, strain-softening zone and strain-hardening zone; (ii) the maximum tangential stress stays in the strain-hardening zone; (iii) the initial stress state can change the shape of PZ. Moreover, for the deeply buried tunnel, the pre-stressing measures show a good potential to control PZ, and the support should be applied as early as possible to reduce the relief of initial stress.