湿陷性黄土地层地铁基坑围护结构变形机理与稳定性控制研究OA

In view of the increasingly prominent problem of the stability of deep foundation pit engineering in col-lapsible loess stratum,based on the ultra-deep foundation pit of Yingze East Street Station of Taiyuan Rail Transit Line 1,the deformation mechanism and stability control measures of the surrounding structure of subway foundation pit in collapsible loess stratum are studied by the combination of field monitoring and theoretical analysis.The re-sults show that the retaining structure presents a typical"bulging"deformation characteristic during the excavation process.The maximum horizontal displacement occurs in the middle and lower part of the pile;The coupling effect of water and soil significantly aggravates the collapsibility of soil and the lateral displacement of retaining structure;Both the cooperative work and pre-stress control of the supporting system play a key role in suppressing deformation.Based on the field monitoring and theoretical analysis,control measures such as strengthening the bending resis-tance of retaining piles,optimizing the stiffness configuration of support system,setting water-proof curtain and soil improvement are put forward to ensure the safety and stability of foundation pit and surrounding environment.The research findings can provide a theoretical basis and practical reference for the design and construction of subway foundation pit engineering under similar geological conditions of collapsible loess strata.