盾构下穿掘进施工对建筑物影响分析

以合肥地铁1号线葛望区间下穿三层框架结构为工程背景,运用MIDAS/GTS软件建立数值分析模型,模拟盾构掘进对上覆建筑物的影响。结果表明:横断面最大累计沉降值发生在两隧道对称轴线上,沉降槽基本呈正太分布曲线;纵向沉降曲线所呈现的规律与上部无结构荷载影响时基本一致;上部建筑结构沉降曲线包括3个平稳和2个剧变阶段,且二次沉降规律明显;上部建筑物荷载对沉降槽宽度及反弯点的位置影响不大,最终沉降会明显增大;地表最大沉降随偏心比e₀的增大逐渐降低,当e₀=1.5时,隧道的最大沉降与上部无结构荷载影响时基本一致,但沉降槽宽度相比而言有所增大;先掘进建筑物下伏隧道、增大注浆压力有利于控制上部建筑物的沉降变形。

Analysis on the Impact of Shield Tunneling on Overlying Buildings

Taking the three-story frame structure under the Gewang section of Hefei Metro Line 1 as the engineering background,a numerical analysis model was established using MIDAS/GTS software to simulate the impact of shield tunneling on overlying buildings.The simulation results show that the cross section is the largest.The accumulated settlement value occurs on the symmetry axis of the two tunnels,and the settlement trough basically presents a normal distribution curve;the longitudinal settlement curve is basically the same as when there is no superstructure load;the building settlement process consists of 3 stable sections and 2 drastic changes,and there is an obvious secondary settlement deformation law;the upper building load has little effect on the width of the settlement trough and the position of the inverted point,and the final settlement will increase significantly;the maximum surface settlement will gradually decrease with the increase of eccentricity ratio e₀.When e₀=1.5,the maximum settlement of the tunnel is basically the same as when there is no upper building,but the width of the settlement trough is increased relatively;it is beneficial to control the settlement of the overlying building by first digging the tunnel underneath the building and increasing the grouting pressure.