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广州珠江新城核心区市政交通项目金穗路以北地下空间基坑位于地铁隧道正上方,基坑开挖、工程(人工挖孔)桩及上盖荷载施工对地铁隧道结构的影响为该工程的关键问题。为此,利用MIDAS/GTS建立有限元模型,对实际的施工工况进行模拟。研究结果表明:隧道结构处于中风化地层的变形量仅为强风化地层的1/3;近距离人工挖孔桩、隧道上方上盖荷载施工及增大转换梁的刚度均能在一定程度上约束隧道的水平和竖向变形;土体偏压开挖对隧道结构水平方向变形影响较大。根据研究结果,提出对下方既有隧道的保护措施,以确保地铁结构安全和正常运营,为设计和施工提供指导意见。
The foundation pit of underground space in north of Jinsui Road, the core area of the Pearl River New City core area in Guangzhou, is located right above the subway tunnel. The influence of excavation, engineering (manual digging holes) pile and superstructure load construction on the subway tunnel structure is as follows The key issue. To this end, the use of MIDAS / GTS established finite element model, the actual construction conditions were simulated. The results show that the deformation of the tunnel structure in the moderately weathered layer is only 1/3 of that in the strongly weathered layer. The construction of the close-hole manual digging pile, the load-bearing construction of the superstructure above the tunnel and the increase of the rigidity of the conversion beam can be restrained to a certain degree The horizontal and vertical deformation of the tunnel; excavation of soil under pressure has a greater impact on the horizontal deformation of the tunnel structure. According to the research results, the protection measures for the existing tunnel underneath are proposed to ensure the safety and normal operation of the subway structure and provide guidance for the design and construction.