隧道施工技术台阶开挖法TunnelConstructionTechnologyBenchExcavationMethod
台阶开挖法目录BenchExcavationMethodTableofContents台阶开挖法的基本概念1长台阶法2短台阶法3超短台阶法45课程小结SettingandApplicableConditionsofCanopyTubeSelectionofSupportParametersforCanopyTubeConstructionProcessofCanopyTubeQualityStandardsandInspectionMethodsofCanopyTubeSummary
台阶开挖法的基本概念01BasicConceptofBenchExcavationMethod
台阶开挖法台阶开挖法的基本概念BenchExcavationMethodBasicConceptofBenchExcavationMethod台阶开挖法，简称“台阶法”，是将设计断面分上半断面和下半断面两次开挖成型。Benchexcavationmethod,alsoknownas“benchcutmethod”,istodividethedesignsectionintoanupperhalfsectionandalowerhalfsection,whichareexcavatedandformedintwotimes.
台阶开挖法台阶开挖法的基本概念BenchExcavationMethodBasicConceptofBenchExcavationMethod台阶开挖法，简称“台阶法”，是将设计断面分上半断面和下半断面两次开挖成型。Benchexcavationmethod,alsoknownas“benchcutmethod”,istodividethedesignsectionintoanupperhalfsectionandalowerhalfsection,whichareexcavatedandformedintwotimes.
台阶开挖法台阶开挖法的基本概念BenchExcavationMethodBasicConceptofBenchExcavationMethod台阶开挖法，简称“台阶法”，是将设计断面分上半断面和下半断面两次开挖成型。Benchexcavationmethod,alsoknownas“benchcutmethod”,istodividethedesignsectionintoanupperhalfsectionandalowerhalfsection,whichareexcavatedandformedintwotimes.
台阶法BenchCutMethod台阶长度Benchlength长台阶法LongBenchCutMethod短台阶法ShortBenchCutMethod超短台阶法Ultra-shortBenchCutMethod台阶开挖法台阶法的分类BenchExcavationMethodClassificationofthestepmethod
长台阶法02LongBenchCutMethod
长台阶法的定义DefinitionofLongBenchCutMethod台阶开挖法长台阶法BenchExcavationMethodLongBenchCutMethod上、下断面相距较远，一般上台阶超前50m以上或大于5倍洞跨。Theupperbenchisgenerallymorethan50maheadormorethan5timesthetunnelspanastheupperandlowersectionsarefarapart.
台阶开挖法长台阶法的施工要点BenchExcavationMethodKeyPointsofConstructionwithLongBenchCutMethod根据支护结构形成闭合断面的时间要求，必要时在开挖上半断面后，可修筑临时底拱，形成上半断面的临时闭合结构，然后在开挖下半断面时再将临时底拱挖掉。上半断面Upperhal