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为分析交错新建隧道施工对既有隧道的影响,采用公路隧道结构与围岩综合试验系统对交错隧道进行三维物理模型试验。测试的内容包括新建隧道开挖引起既有隧道围岩内部压应力、围岩内部位移及支护结构内力的变化规律。试验结果表明,既有隧道拱顶径向压应力和拱腰切向压应力具有增加趋势,拱顶切向压应力和拱腰径向压应力具有减小趋势;拱顶围岩内部位移表现为压缩变形,拱腰围岩内部位移为拉伸变形;既有隧道支护结构的轴力和弯矩全为增加,右拱腰的弯矩受到的影响最大;新建隧道施工对既有隧道L8截面的影响较小,对L1和L4截面的影响非常明显,当间距小于L8截面情况时应采取加固措施。
In order to analyze the influence of staggered new tunnel construction on the existing tunnels, a three-dimensional physical model test was conducted on the staggered tunnel by using the comprehensive test system of highway tunnel structure and surrounding rock. The contents of the tests include the changes of internal compressive stress in the surrounding rock of existing tunnels, the displacement of the surrounding rock and the internal forces of the support structure caused by the new tunnel excavation. The test results show that the radial compressive stress and the arch-tangential compressive stress of the existing tunnel arch have an increasing trend, and the tangential compressive stress of the arch and the radial compressive stress of the arch waist have a decreasing trend. The displacement of the surrounding rock dome shows Compressive deformation and internal displacement of arch waist and surrounding rock are tensile deformation; the axial force and bending moment of the existing tunnel support structure are all increased and the bending moment of right arch waist is the most affected; the construction of new tunnel on the existing tunnel L8 section Of the impact of the L1 and L4 cross-section of the impact is very obvious, when the spacing is smaller than the L8 cross-section should take reinforcement measures.