考虑流变效应的泥岩隧道仰拱变形特征研究

Study on Deformation Characteristics of Tunnel Inverts in Mudstone Considering Rheological Effects

  • 摘要: 为探讨泥岩流变效应对隧道结构长期受力变形规律的影响,采用Burgers模型进行流变数值计算,将计算结果与国内外类似情况的隧道长期监测数据进行对比讨论,以验证其合理性和正确性。结果表明,流变效应下,运营期内围岩有整体向内“流动”变形的趋势,其中基底隆起最为明显,且仰拱变形呈现出中间大两端小的“枣核状”,仰拱及填充层位移均随时间呈增长趋势,50 a后基本保持稳定;填充层处于受拉状态,各部位最大主应力随时间持续增长,在距拱脚1/4洞径处出现峰值,接近C25混凝土抗拉强度;实际工程中,仰拱底鼓特征表现为长时效、难收敛,因此,对泥岩类隧道设计施工时要考虑泥岩流变特性及其对隧道结构长期变形受力的影响。

     

    Abstract: In this paper, to explore the influence of mudstone rheological effect on the long-term stress deformation law of tunnel structures, the Burgers model is used for rheological numerical calculation. The calculation results are compared and discussed with long-term monitoring data of tunnels in similar situations at home and abroad to verify its rationality and correctness. The results show that under the rheological effect, the surrounding rock shows a trend of overall inward "flow" deformation during operation stage, the base uplift is the most obvious, and the deformation of the invert presents a "jujube pit" shape with a large middle and two small ends. The displacement of the invert and the filling layer shows an increasing trend over time, and remains basically stable after 50 years. The filling layer is in a tensile state, and the maximum principal stress in each part continues to increase over time, reaching a peak at 1/4 of the tunnel diameter away from the arch floor, and approaching the tensile strength of C25 concrete. In the practical project, the characteristics of invert floor heave are characterized by long time effect and difficulty in convergence. Therefore, when designing and constructing tunnels in mudstone, it is necessary to consider their rheological characteristics and their impact on the long-term deformation and stress of the tunnel structure.

     

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