漫滩地层小尺寸方形深基坑内支撑方案研究
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中图分类号：TU318.1;TQ178
文献标志码：A 文章编号：1001-5922（2025）10-0207-04
Research on internal support scheme ofsmall size square deep foundation pit in floodplain stratum
FAN Yongge1， CHEN Dong²， WANG Zhide³ （1.Kunming Xinzhi Investment Development Co.，Ltd.，Kunming 650599，China; 2. Yunnan Vocational and Technical College of Transportation，Kunming 65o5O4，China; 3.Wuhan Universityof Technology，Wuhan 43oo70，China）
Abstract：The internal supportof thedeep foundation pitofasmall-sized square interval airshaft inthe Yellow River floodplain stratum adopts the diagonal bracing design scheme.The supporting structure adopts the calculation and designof the Lizheng deep foundationpit.Thehorizontal displacementof theretaining pile inthe excavation constructionof the foundation pit exceedsthe limit risk.In this paper，the problems existing in theconstructionof foundation pit and the measured results are analyzed，and the horizontal displacement deformation law of retaining pileunder diferent internal supportschemes iscalculatedby three-dimensional finite element method.Theresults show that the calculation results of Lizheng deep foundation pit show that the third support adopts steel support or concrete support scheme，and the horizontal deformationvalue of foundation pit retaining pile meets the requirements of thecode.The field measurement results show thatthe horizontal displacementof the foundationpitretaining pile exceeds the standard limit of 32.36% ，and the maximum deformation is located at the third steel support. The axial force value of the support is only 24% of the theoretical calculation value，and the steel support does not play an efective supporting role.Combined with the problems existing in the construction of steel waist beam and stel support，itisconsidered thatthere isdisspation between horizontalsoil pressureand inclinedsupport，which leads tothe failure of inclined steel support to effectively restrain the horizontal deformation ofretaining pile.
Key words：square air shaft;deep foundation pit;Internal support;field monitoring
地铁区间风井常设置于线路纵坡的最低点兼作联络通道使用，该类风井基坑平面尺寸小，基坑开挖深度大，为便于施工作业，内支撑多数采用斜支撑设计，支护结构受力与狭长型车站基坑存在一定差异。（剩余4811字）
