不同方位溶洞对盾构施工隧道位移影响研究

Analysis of effects of different azimuth caves on displacement of shield construction tunnels

为探究溶洞方位及尺寸对隧道围岩稳定性的影响,以昆明地铁4号线岩溶区段为依托,通过Midas软件进行数值模拟,对盾构掘进工程中围岩位移及应力响应进行分析,并以实际监测进行验证.结果表明,盾构开挖时,隧道拱顶沉降3.31 mm,拱底隆起3.58 mm,拱腰收敛1.62 mm;溶洞对溶隧形心方向上位移起屏蔽作用,位移随尺寸增大显著减少,与溶隧方向正交的位移则因围岩刚度的削弱而增加;侧部溶洞对施工过程中围岩稳定性影响最大,下部次之,上部最小,工程中应优先对侧部、底部溶洞进行处置.

In order to explore the influence of cave orientation and size on the stability of tunnel surrounding rock,this paper relied on the karst section of Kunming Metro Line 4,carried on numerical simulation through Midas software,analyzed the displacement and stress response of the surrounding rock in the shield excavation project,and verified it with actual monitoring.The results showed that when the shield was excavated,the tunnel vault sank 3.31 mm,the arch edill up 3.58 mm,the arch waist convergence 1.62 mm,and the cave shielded the upper displacement in the direction of the dissolved tunnel heart,and the displacement increased significantly with the size.Reduced,and the direction of the tunnel orthogonal displacement was increased by the weakening of the rigidity of the surrounding rock,the side cave on the construction process of the most impact on the stability of the surrounding rock,the lower part of the second,the upper smallest,the project should be priority to the side,bottom cave disposal.