In order to explore the influence of the new subsurface tunnel between Dongdaqiao Station and Jingguangqiao Station of Beijing Metro Line 28 on the settlement of the existing pipeline under different working conditions and to optimize its construction scheme,numerical calculation and optimization analysis are carried out using FLAC3D finite-difference program.The results show that the settlement of the existing pipeline caused by the construction of the new line decreases with the increase of the cyclic footage of excavation,the strength and thickness of the initial support,and the index of grouting reinforcement,and increases with the increase of the height of the upper step,and it shows a significant trend of increasing due to the excavation of the upper step without reserving the core soil or the abolition of the locking footing anchor support.The following optimisation options were derived and it was recommen-ded to excavate the upper step without reserving the core soil,or to increase the excavation cycle feed to 1.0 m,or to reduce the thickness of the initial support to 200 mm.The conclusions of the study can be used as a reference for the subsurface underground tunnel crossing project in Beijing.
关键词
地铁隧道/平行穿越/既有市政管线/数值模拟/优化分析
Key words
Subway tunnel/Parallel crossing/Existing municipal pipeline/Numerical simulation/Optimiza-tion analysis
维普
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