隧道下穿施工诱发框架结构建筑物变形规律研究

Simulation study of deformation of frame structure caused by construction of under-crossing tunnels

隧道下穿既有高大建筑物越来越多的出现在城市地铁建设中,有必要对建筑物受地铁隧道下穿影响发生变形的规律进行研究。采用FLAC3D软件,考虑建筑物–土体–隧道共同作用,模拟了双线暗挖隧道先后穿越独立基础框架结构建筑物的工况。模拟结果表明框架结构的存在对隧道开挖引发的沉降位移曲线形状有明显影响,沉降槽深度明显减小,宽度有所增加。在垂直于隧道方向,上部结构的存在减小了柱间沉降差,使框架结构柱间基础沉降趋于平缓。最终柱间沉降差较大值出现在沉降槽曲线拐点两侧框架柱间。在平行于隧道方向,建筑物柱间沉降差与隧道掌子面位置密切相关,掌子面位置前后两柱间沉降差较大。隧道通过后,该方向上最终柱间沉降差将很小。

Considering the interaction of building-soil-tunnel,the case of frame building with independent foundation undercrossed by double-line parallel shallow embedded tunnel is simulated by FLAC3 D. The results show that the stiffness of frame structure has a remarkable effect on foundation settling tank of the upper building. In the direction of perpendicular to the tunnel axis, the largest differential settlement between two frame columns usually happens around the inflection point of settlement curve, and the existence of the upper structure reduces the differential settlement between columns. The differential settlement relates to the relative position of tunnel face in the direction of parallel to tunnel axis, while it will be a very small value when the tunnel face is far away enough.