盾构隧道下穿引起砌体结构建筑沉降损伤实例研究
Case study of tunneling-induced settlement and damage of masonry buildings
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摘要: 盾构掘进引起地层变形过大极易导致上方沉降敏感结构物变形开裂。对某地铁盾构隧道正交下穿砌体结构建筑物进行研究。通过对建筑物沉降进行系统监测和对建筑物进行全面巡查,获得了双线盾构隧道施工过程引起建筑物沉降及裂缝开展状况。通过三维有限元模型研究了建筑物-地层变形相互作用规律,对比分析了墙体主拉应变云图与实测裂缝分布规律,发现当隧道下穿引起的主拉应变超过0.05%的墙体区域会产生裂缝,且墙体裂缝的发展角度与该处的主拉应变方向垂直。最后根据墙体最大主拉应变讨论了建筑物损伤程度和损伤等级。盾构掘进引起上方砌体建筑物损伤案例,对地铁施工过程中砌体建筑保护具有一定的指导作用和参考价值。Abstract: The excessive deformation caused by shield tunneling can easily lead to deformation and cracking of the above sensitive structures. A masonry building orthogonally under-passed by metro shield tunnels is studied. Through systematic settlement monitoring and comprehensive inspection of the building, the tunneling-induced settlements and crack development of the building are obtained. A finite element model is established to study the interaction of the building and the soils. By comparing the principal tensile strain and the measured crack distribution of the wall, it is found that when the principal tensile strain exceeds 0.05%, cracks will occur in the wall area and the development angle of the wall crack is perpendicular to the direction of the principal tensile strain there. Finally, the damage degree and level of the building are discussed according to the maximum principal tensile strain of the wall. The case study of masonry building damage caused by shield tunneling is of certain guiding and reference values for protection of masonry buildings during subway construction.