预筑拱控制软弱围岩变形机理的研究

发布时间：2019-05-30 06:34

【摘要】：软弱围岩变形主要发生在掌子面前方,控制软弱围岩变形的关键环节是控制掌子面前方变形,即预收敛。预筑拱以其横向连续性好、施工速度快等特点在控制软弱围岩预收敛方面具有良好效果。文章通过FLAC3D建立三维数值模型,分析研究了预筑拱控制软弱围岩变形的机理。研究发现:(1)预筑拱能有效地控制隧道预收敛变形、收敛变形以及隧道上方围岩变形,围岩条件变差时预筑拱作用效果更加明显;(2)预筑拱能够有效地控制掌子面前方围岩的应力释放,从而有效地控制隧道上方坍落拱的发展范围,限制拱顶区坍落拱的分布区域,减少开挖对围岩的扰动,限制围岩应力重分布程度;(3)由于限制围岩应力释放,预筑拱所受围岩荷载比传统支护所受围岩荷载大。
[Abstract]:The deformation of weak surrounding rock mainly occurs in front of the palm face, and the key link to control the deformation of the weak surrounding rock is to control the deformation in front of the palm surface, that is, pre-convergence. The prebuilt arch has a good effect on controlling the pre-convergence of weak surrounding rock because of its good transverse continuity and fast construction speed. In this paper, a three-dimensional numerical model is established by FLAC3D, and the mechanism of controlling the deformation of weak surrounding rock by pre-built arch is analyzed and studied. It is found that: (1) the pre-built arch can effectively control the pre-convergence deformation of the tunnel, the convergence deformation and the deformation of the surrounding rock above the tunnel, and the effect of the pre-arch is more obvious when the surrounding rock conditions become worse; (2) the pre-built arch can effectively control the stress release of the surrounding rock in front of the palm surface, thus effectively control the development range of the collapse arch above the tunnel, limit the distribution area of the collapse arch in the arch roof area, and reduce the disturbance of excavation to the surrounding rock. Limit the degree of stress redistribution of surrounding rock; (3) due to the limitation of stress release of surrounding rock, the surrounding rock load of pre-built arch is larger than that of traditional support.
【作者单位】：北京交通大学土木建筑工程学院;
【基金】：国家自然科学基金(51178026)
【分类号】：U451.2

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