不同地质条件下隧道洞口仰坡地震破坏特性研究

发布时间：2019-03-05 08:29

【摘要】：针对洞口段均质围岩仰坡、含软弱夹层仰坡和桁架梁加固仰坡围岩3种工况,开展大型振动台模型试验,分析隧道洞口段仰坡模型土破坏形态。试验结果表明,均质边坡洞口段模型土在动力作用下坡肩土体先出现张拉裂缝,随着激振加速度增加,坡肩土体局部出现倾倒崩塌,最后沿坡面滑落堆积;含软弱夹层边坡在地震力作用下,仰坡坡脚部位土体挤压破碎,坡顶表面沿软弱夹层位置出现张拉裂缝,上覆土体沿软弱夹层滑动,最后土体大规模崩塌、滑落;洞口段加固边坡在动力作用下基本保持整体稳定,只部分梁格出现了局部的掉块,模型土顶部出现沿隧道轴向的细微裂缝。分析了隧道洞口段衬砌结构破坏形态,试验结果表明均质边坡洞口段AB两段衬砌模型裂缝分布较CD段复杂,认为洞口段地震影响深度为AB两段衬砌的长度,对应于实际工程中40 m;受软弱夹层影响,跨软弱夹层部衬砌模型裂缝形态较复杂;仰坡加固后,洞口段衬砌模型受力改善。研究结果可为山岭隧道洞口段边坡抗减震研究和设计提供参考。
[Abstract]:In this paper, the large-scale shaking table model test is carried out to analyze the soil failure pattern of the tunnel entrance elevation model, aiming at the homogeneous surrounding rock slope of the tunnel entrance, the soft sandwich slope and the truss beam strengthening the surrounding rock of the elevation slope under the conditions of three kinds of conditions, the large-scale shaking table test. The experimental results show that under the dynamic action of the model soil at the entrance section of homogeneous slope, tension cracks first appear in the slope shoulder soil, and with the increase of the acceleration of excitation, the slope shoulder soil collapses and collapses locally, and finally falls and accumulates along the slope surface. Under the action of earthquake force on the slope with soft interlayer, the soil at the foot of the slope is crushed, the surface of the slope appears tension cracks along the position of the weak interlayer, the overlying soil slides along the weak interlayer, and the soil collapses and falls on a large scale at the end of the slope. Under the dynamic action, the slope under the dynamic action basically keeps the whole stability, only part of the beam appears partial drop block, and the top of the model soil appears fine cracks along the tunnel axis. The failure pattern of lining structure in tunnel entrance section is analyzed. The experimental results show that the crack distribution of AB two-segment lining model is more complicated than that of CD section in homogeneous slope. It is considered that the depth of seismic influence of tunnel entrance section is the length of AB two-segment lining, and the distribution of cracks is more complicated than that of CD section. Corresponding to the actual engineering 40 m; Under the influence of weak interlayer, the shape of cracks in the lining model across the soft sandwich is more complicated, and the stress of the lining model in the opening section is improved after the reinforcement of the upward slope. The results can be used as reference for the study and design of slope anti-vibration in the entrance section of mountain tunnel.
【作者单位】：西南交通大学交通隧道工程教育部重点实验室;
【基金】：国家自然科学基金资助(No.51178398)
【分类号】：U452.28

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