Spatial　effects　and　enclosure　structure　are　ignored　in　the　design　process　of　the　circular　excavation.　And　in　order　to　solve　this　problem,　based　on　the　circular　arc　sliding　model　of　limit　equilibrium　method,　a　three-dimensional　axisymmetric　arc　sliding　method　(TAASM),　in　which　the　stiffness　of　the　enclosure　structure　was　considered,　was　proposed.　The　spatial　effects　also　was　considered　by　including　the　circumferential　stress,　which　was　deduced　in　terms　of　the　elastic　foundation　beam　method　and　the　circular　ring　axisymmetric　method,　action　on　the　sliding　surface　in　TAASM.　Furthermore,　the　TAASM　was　applied　to　check　a　practical　engineering　and　its　result　was　compared　with　other　method　results.　Also,　the　effects　of　certain　factors　or　parameters,　including　the　maximum　lateral　displacement,　radius　of　excavation,　excavation　depth,　embedded　depth　and　parameters　of　soil　were　analyzed.　Results　show　that:　the　TAASM　considers　not　only　the　effects　of　the　enclosure　structure　stiffness　and　deformation　but　also　the　spatial　effects　of　circular　excavations　on　the　sliding　surface　and　its　result　is　relatively　reasonable;　in　circular　excavations,　the　ability　of　mutual　constraints　between　the　sliding　body　and　adjacent　soil,　the　spatial　effects　of　self-stability　and　the　calculated　basal　heave　stability　safety　factor　obtained　by　TAASM　decrease　simultaneously　with　the　increase　of　the　maximum　lateral　displacement　of　enclosure　structure;　by　TAASM,　the　calculated　safety　factor　of　basal　heave　stability　for　circular　excavations　is　larger　than　that　by　any　other　existing　plane　algorithm,　so　the　embedded　depth　of　enclosure　structure　may　be　optimized　to　lower　the　enclosure　structure　cost.　©　2018,　Editorial　Department　of　Journal　of　Beijing　University　of　Technology.　All　right　reserved.