张敏, 黄润秋, 巨能攀. 2008: 浅埋偏压隧道出口变形机理及稳定性分析. 工程地质学报, 16(4): 482-488.
    引用本文: 张敏, 黄润秋, 巨能攀. 2008: 浅埋偏压隧道出口变形机理及稳定性分析. 工程地质学报, 16(4): 482-488.
    ZHANG Min, HUANG Runqiu, JU Nengpan. 2008: DEFORMATION MECHANISM AND STABILITY ANALYSIS OF A HIGH SLOPE AT PORTAL OF COMPRESSED TUNNELAT SHALLOW DEPTH. JOURNAL OF ENGINEERING GEOLOGY, 16(4): 482-488.
    Citation: ZHANG Min, HUANG Runqiu, JU Nengpan. 2008: DEFORMATION MECHANISM AND STABILITY ANALYSIS OF A HIGH SLOPE AT PORTAL OF COMPRESSED TUNNELAT SHALLOW DEPTH. JOURNAL OF ENGINEERING GEOLOGY, 16(4): 482-488.

    浅埋偏压隧道出口变形机理及稳定性分析

    DEFORMATION MECHANISM AND STABILITY ANALYSIS OF A HIGH SLOPE AT PORTAL OF COMPRESSED TUNNELAT SHALLOW DEPTH

    • 摘要: 以皖南某公路浅埋偏压隧道出口段高边坡为研究对象,提出了零开挖进洞的施工方案,并结合洞口的工程地质条件,采取必要的加固措施。通过对该边坡现场工程地质条件的系统调查,首先对边坡的岩体结构类型及其成因机制、结构面与坡面组合特征进行细致研究,在此基础上通过FLAC3D数值模拟,结合工程地质条件分析,对其变形破坏机制进行深入探讨。研究结果表明,边坡的变形首先以隧道内侧存在的软弱岩体(挤压错动带、断层)的不均匀压缩为先导,进而引起上部岩体产生由NE向陡缓结构面构成的阶梯状滑动,这将会使隧道构筑物及隧道外壁承受较大的压应力,当压应力超过隧道构筑物及外壁的极限强度时将产生破坏,从而诱发上部岩体产生更大规模的地质灾害。基于此,隧道进洞开挖前首先应对上部岩体进行加固处理,避免隧道构筑物及隧道外壁产生应力集中现象。

       

      Abstract: This paper examines a high slope at the portal of a compressed highway tunnel with shallow depth in south Anhui province. The construction design of zero excavation is proposed to maximally protect the geological environment and prevent the large-scale geological disasters. The necessary reinforcement measures are used by taking intco consideration of the site engineering geological conditions. The site engineering geological conditions are investigated systematically. Then the types and causes of rock mass structures and the combination between structural planes and slope surface are studied in detail so as to analyze the slope deformation mechanism. A geological model of this high slope is described with engineering geological profile. The detailed descriptions of the geological sketches are conducted. It is demonstrated that the slope deformation is always initiated by the non-uniform compression of the unconsolidated rock mass, leading to ladder sliding along the combination between structure planes with high dip angles and structure planes with low dip angles paralleling with slope. The ladder sliding makes greater stress to the structures and surrounding rocks of the tunnel. Failures can occur when the supplementary pressure exceeds their strengths, which will induce great geohazards. The result of FLAC3D numerical modeling indicates that the stress concentration distributes along the unconsolidated rock mass near the inside of this tunnel. The tensile stress zone can occur in the upper rock mass. Based on the analysis, before tunnel excavation, reinforcement measures should to be implemented to avoid stress concentrations on the tunnel structure and surrounding rocks.

       

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