有限空间新建设施基坑开挖沉降特征及小变形控制.docx
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1、有限空间新建设施基坑开挖沉降特征及小变形控制仇安兵区北京科技大学基建管理处,北京100O83区1通信作者,E-mail:qiu-anbing摘要针对有限空间新建基坑变形控制难题,采用理论分析、数值推演和工程实践相结合的研究方法,建立了考虑应力释放的有限空间夹持力学模型,推导了夹持应力与地层损伤因子的函数关系,研究了应力释压孔对有限空间地层应力的影响特征,提出了变形支挡-应力阻隔一体结构控制方法,并通过北京科技大学工程实践基地(二期)验证该方法的有效性.结果表明,地层损伤因子与夹持应力呈线性负相关关系,随开挖深度逐渐增大,布设释压孔可有效降低有限空间夹持应力,释压孔有利于调整地层夹持应力和控制地
2、层变形,变形控制率为3348%5872%,且变形支挡-应力阻隔一体结构控制方法的水平变形控制率为2857%3791%,地层沉降变形控制率为36.86%5426%,与数值模型计算结果趋势相同,论证了理论分析和数值推演结果有效性,为有限空间基坑稳定性控制提供数据支撑.关键词有限空间;建筑基坑:释压孔;小变形控制;智能动态监测分类号TU473StudyonsettlementcharacteristicsandmicrodefbrmationcontroloffoundationpitexcavationinnewfacilitieswithlimitedspaceQIUAnhingInfrastr
3、uctureManagementOffice,UniversityofScienceandTechnologyBeijing.Beijing100083.China国Correspondingauthor.E-mail:qiu-anbingABSTRACTToaddresstheproblemofdeformationcontrolofanewfoundationpitinfinitespace,amechanicalmodelofstrongmutualclampinginfinitespaceconsideringstressreleaseisdevelopedbasedontheplan
4、estrainmethodofelasticmechanicsbycombiningtheoreticalanalysis,numericaldeduction,andengineeringpractice.Theformationdamagefactorisintroducedtodistinguishthestructuralfailurestateoftheformation,andthefunctionalrelationshipbetweentheclampingstressandtheformationdamagefactorisobtained.Anumericaldeducti
5、onmodelofthestressbarrierinfinitespaceisconstructed.Theinfluenceofstressreleaseholesonthestressstructureofnitespaceisexamined,andanintegratedstructuralcontrolmethodfordeformationsupportandstressbarrierisproposed.TheeAectivenessofthemethodwasvalidatedbytheengineeringpracticebaseprojectoftheUniversity
6、ofScienceandTechnologyBeijing.Thefindingsrevealthatunderthestrongmutualclampingeffectbetweenthelateralearthpressureoftheexistingbuildingandthesupportingreactionforceofthefoundationpit,theformationdamagefactorhasalinearnegativecorrelationwithclampingstress.Theverticalstressintheshallowpartofthemodelw
7、ithoutapressurereliefholeincreasesgraduallyandthendecreasesandsetsnear21.2-22.5kPa.Theverticalstresslevelofthemodelwithapressurereliefholeis40kPalowerthanthatofthemodelwithoutapressurereliefhole.Thehorizontalstressoftheshallowlayerwithoutthepressurereliefholefirstincreases,thendecreases,andgradually
8、increasestoamaximumvalueof94.72kPaintheearlystageoffoundationpitexcavation.Thepeakvalueofhorizontalstressisloweredby65.51%,andtheeflectivereleaseofformationstressis43.55%-65.51%.Thesettlementofthefoundationpitincreasesgraduallywithincreasingexcavationtime.Themaximumhorizontaldefbnationofthemodelwith
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- 关 键 词:
- 有限 空间 新建 设施 基坑 开挖 沉降 特征 变形 控制