考虑气压效应的浅埋隧道开挖影响解析解答

发布时间：2019-05-17 08:43

【摘要】：基于隧道开挖椭圆化变形模式,针对盾构施工分别考虑气压效应与无气压效应2种工况,提出饱和土中浅埋隧道开挖引起的地层长、短期变形和隧道衬砌内力位移的计算方法。结果表明:椭圆化变形模式下得到的位移曲线与实测值吻合较好,考虑气压效应条件下隧道开挖施工引起的土体变形大于非气压工况,长期影响解大于短期影响解。通过参数调整研究衬砌洞周处位移分布规律时,发现衬砌径向负位移在90°拱顶处达到最大值,在270°拱底处取得最小值,反映了衬砌明显的椭圆化和整体下沉变形趋势,并且随着半径增大以及土体模量减小,椭圆化变形趋势越明显;切向位移值基本以90°/270°隧道中轴线为分界轴,正值取在隧道左半圆,负值取在隧道右半圆,增大半径以及减小土体模量提高了切向位移值的整体水平。通过参数调整研究衬砌内力分布规律时,发现硬土质和大间隙时隧道轴力更容易表现出明显的椭圆化分布趋势,弯矩值随着隧道埋深、隧道半径以及土体重度减小而减小,随着土体侧压力系数k的减小而增大。盾构气压水平的提升,使衬砌轴力受压区范围增幅明显,并使衬砌的正、负弯矩值均增大。分析成果可为正确预估复杂工况下盾构开挖变形提供一定的理论依据。
[Abstract]:Based on the elliptical deformation mode of tunnel excavation, the calculation methods of long, short-term deformation of strata and internal force and displacement of tunnel lining caused by shallow tunnel excavation in saturated soil are put forward according to the consideration of air pressure effect and no air pressure effect in shield construction. The results show that the displacement curve obtained under the elliptical deformation mode is in good agreement with the measured values. The soil deformation caused by tunnel excavation under the condition of air pressure effect is larger than that under non-air pressure condition, and the long-term influence solution is larger than the short-term influence solution. When the displacement distribution around the lining hole is studied by parameter adjustment, it is found that the radial negative displacement of the lining reaches the maximum at the 90 掳arch roof and the minimum value at the bottom of the 270 掳arch, which reflects the obvious elliptical and overall subsidence and deformation trend of the lining. With the increase of radius and the decrease of soil modulus, the trend of elliptical deformation is more obvious. The tangential displacement value is basically 90 掳/ 270 掳tunnel axis as the dividing axis, the positive value is taken from the left half circle of the tunnel, and the negative value is taken from the right half circle of the tunnel. The overall level of the tangential displacement value is improved by increasing the radius and reducing the soil modulus. When the internal force distribution of lining is studied by parameter adjustment, it is found that the axial force of tunnel tends to show obvious elliptical distribution trend when hard soil and large clearance are used, and the bending moment decreases with the decrease of tunnel depth, tunnel radius and soil weight. It increases with the decrease of lateral pressure coefficient k. With the increase of shield air pressure level, the range of axial force compression zone of lining increases obviously, and the positive and negative bending moments of lining increase obviously. The analysis results can provide a certain theoretical basis for correctly predicting the excavation deformation of shield under complex working conditions.
【作者单位】：国土资源部丘陵山地地质灾害防治重点实验室;上海理工大学环境与建筑学院;成都理工大学地质灾害防治与地质环境保护国家重点实验室;华东建筑设计研究院有限公司;
【基金】：上海自然科学基金项目(15ZR1429400) 国土资源部丘陵山地地质灾害防治重点实验室课题(2015k005) 成都理工大学地质灾害防治与地质环境保护国家重点实验室基金项目(SKLGP2015K015)~~
【分类号】：U455.43

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