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洪秋阳, 来弘鹏, 周阳. 循环加卸载作用下大断面黄土隧道衬砌结构受力试验研究[J]. 岩土工程学报. DOI: 10.11779/CJGE20240871
引用本文: 洪秋阳, 来弘鹏, 周阳. 循环加卸载作用下大断面黄土隧道衬砌结构受力试验研究[J]. 岩土工程学报. DOI: 10.11779/CJGE20240871
Experimental study on the stress of loess tunnel lining structure under cyclic loading and unloading[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20240871
Citation: Experimental study on the stress of loess tunnel lining structure under cyclic loading and unloading[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20240871

循环加卸载作用下大断面黄土隧道衬砌结构受力试验研究

Experimental study on the stress of loess tunnel lining structure under cyclic loading and unloading

  • 摘要: 浅埋大断面黄土隧道修建后极易出现地表裂缝,在季节性降雨或农业灌溉的周期性入渗作用下,衬砌结构经历反复加卸载作用,引发严重结构病害。鉴于此,本文探究了循环加卸载作用下大断面黄土隧道衬砌结构受力规律,分析了不同荷载峰值、不同循环加载次数下衬砌结构力学响应特征和破坏机制。研究结果表明:循环加卸载作用下隧道衬砌结构呈现弹性变形、渐进开裂、裂缝扩展3种响应模式,对应外荷载分别为小于53.2%、79.8%~100%之间以及大于开裂值。弹性变形模式中衬砌结构内力值稳定,轴力在-932 kN以内,弯矩在-233 kN•m ~ 230 kN•m之间;渐进开裂模式中结构经历多次加卸载后表面出现裂缝,最小安全系数由0.34~0.42下降至0.23以下;裂缝扩展模式中结构已开裂部位在加卸载过程中出现应力集中,裂缝迅速扩大,未损伤部位内力值保持稳定。

     

    Abstract: Surface cracks are prone to occur in shallow buried large cross-section loess tunnels. The lining structure undergoes repeated loading and unloading actions under the periodic infiltration of seasonal rainfall or agricultural irrigation. It leads to serious structural diseases. In view of this, the stress law of the lining structure of large-section loess tunnels under cyclic loading-unloading is explored in this article. And the mechanical response characteristics and failure mechanism of the lining structure under different load peaks and cyclic loading times is analyzed. The research results indicate that the lining structure exhibits three response modes under cyclic loading and unloading: elastic deformation, progressive failure, and direct cracking. The external loads are between less than 53.2%, 79.8%~100%, and greater than the loading failure value, respectively. Under the elastic deformation mode, the internal force value is stable. The axial force ranges below -932 kN, and the bending moment ranges from -233 kN•m to 230 kN•m. During the progressive failure stage, cracks appear on the surface after multiple loading and unloading cycles. The minimum safety factor decreases from 0.34 to 0.42 to below 0.23. In the crack propagation mode, stress concentration occurs in the cracked parts of the structure during loading and unloading, and the cracks rapidly expand. The internal force value of the un-cracked area remains stable.

     

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